ALEXANDRA VAN DER GEER

Publications

Vertebrate Palaeontology, Indology, Languages

publications



Research interests: mammalian palaeontology, island biogeography, extinctions, comparative morphology, mammalian systematics and phylogeny, ethnobiology, geomythology.

A number of publications can be downloaded from this site, others can be requested (geeraae@geol.uoa.gr) or downloaded from ResearchGate (see below). My Dutch books can be lend at the Koninklijke Bibliotheek (KB) at The Hague, the Netherlands (printversion search results). Note that conference abstracts, posters and editorials are not included here.

[ResearcherID (Thomson Reuter Web of Knowledge)]
[Scopus ID]
[Research Gate]
[Dutch Studies (Indology)]

Disclaimer: Any PDF files provided below are for personal use only and may not be reproduced. The files reflect the holdings of the various publishers and only contain the relevant pages, and may not be complete. Users are obliged to follow all copyright restrictions.




  • 2021 van der Geer A, Lyras G, de Vos J. Evolution of Island Mammals: Adaptation and Extinction of Placental Mammals on Island.
    Wiley-Blackwell, UK, 576 pages; ISBN 139781119675730, eISBN 9781119675716.

    Evolution on islands differs essentially from evolution on mainlands. Especially islands of the past are uniquely intriguing. Due to millions of years of isolation, exceptional and sometimes bizarre mammals evolved, such as pig-sized elephants and hippos, giant rats and gorilla-sized lemurs, formidable to their mainland ancestors. This Second Edition provides an updated and expanded overview of the current knowledge on fossil island mammals worldwide, ranging from the Oligocene to the onset of the Holocene, with examples of the fragmentary Cretaceous record. The book addresses evolutionary processes and key aspects of insular mammal biology, exemplified by a variety of fossil species. Readers familiar with the first edition will find here a host of updated and enhanced material, including: An entirely new chapter on the island rule, Updated and expanded theoretical chapters, Updated and improved taxonomic information, Extensive coverage of new discoveries, Body masses or body size indices for most extinct island mammals, New figures visualizing the richness of the fossil record This accessible and richly illustrated textbook is written for graduate level students and professional researchers in evolutionary biology, palaeontology, biogeography, zoology, and ecology.
    [Publisher site]


  • in review van der Geer AAE, Claessens LPAM, Rijsdijk KF, Lyras GA. The changing face of the dodo (Aves: Columbidae: Raphus cucullatus): iconography of the Walghvogel of Mauritiu.
    Historical Biology


  • 2021 Louys J, Braje TJ, Chang C-H, Cosgrove R, Fitzpatrick SM, Fujita M, Hawkins S, Ingicco T, Kawamura A, MacPhee RDE, McDowell MC, Meijer HJM, Piper PJ, Roberts P, Simmons AH, van den Bergh G, van der Geer A, Kealy S, O’Connor S. No evidence for widespread island extinctions after Pleistocene hominin arrival.
    Proceedings of the National Academy of Sciences of the USA 118(20), e2023005118; DOI: 10.1073/pnas.2023005118.

    We provide global assessment of the possible link between Pleistocene hominin arrival and island extinction. The existing records on islands around the world do not support a significant and detrimental impact on island biotas following island colonization prior to the Holocene. This suggests that models using island extinctions as evidence in support of anthropogenic megafaunal overhunting, or as extensions of continental-level extinctions, need to be reconsidered
    [Open Access]


  • 2020 van der Geer AAE. Size matters: micro-evolution in Polynesian rats highlights body size changes as initial stage in evolution. PeerJ 8, e9076. doi:10.7717/peerj.9076

  • 2019 Athanassios A, van der Geer AAE, Lyras GA. Pleistocene insular Proboscidea of the Eastern Mediterranean: a review and update. Quaternary Science Reviews 218, 306-321. doi: 10.1016/j.quascirev.2019.06.028

  • 2019 Volmer R, van der Geer AAE, Cabera PA, Unggul W Prasetyo, Kurniawan I. When did Cuon reach Java? - Reinvestigation of canid fossils from Homo erectus faunas. Geobios 55, 89-102. doi: 10.1016/j.geobios.2019.06.004 [ScienceDirect]

  • 2019 Van der Geer AAE. Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific. PeerJ article 32784.

    Populations of vertebrate species introduced onto islands regularly develop similar phenotypic changes, e.g. larger or smaller body size, shortened limbs, duller coats, as well as behavioural changes such as increased tameness and reduced flight-initiation distance. These changes overlap in part with those associated with the domestication syndrome, especially tameness and changes in coat patterns, and might indicate a similar neural crest involvement in the concurrent development of multiple phenotypic traits. I examined long-term data on free-living populations of wild Polynesian rats from seven mainland countries and 117 islands (n=3034), covering the species native and introduced range. Mainland populations showed no aberrant coat patterns, with the exception of one albino, whereas aberrant coat patterns were found in 12 island populations. Observed coat colour polymorphisms consisted of leucistic (including singular white patches), melanistic (darkly pigmented) and piebald (mixed) coat patterns. After isolation for at least seven centuries, wild Polynesian rat populations on islands seem to exhibit a trend towards a higher incidence of aberrant coat patterns. These phenotypic changes are here explained as a neutral, non-adaptive process, likely part of the domestication syndrome (via the commensal pathway of domestication), in combination with genetic drift, little or no gene flow between the islands and/or the mainland and a relaxed selection (as a result of the weakening or removal of competitor / predator pressure) under commensality

  • 2019 Kouvari M, van der Geer AAE. Corrigendum to Biogeography of Extinction: the demise of insular mammals from the Late Pleistocene till today” [PALAEO 505 (15 September 2018) pages 295-304]. Palaeogeography, Palaeoclimatology, Palaeoecology 518, 232-233; DOI: 10.1016/j.palaeo.2019.01.024 [ScienceDirect]


  • 2019 Lyras GA, Giannakopoulou A, Lillis T, van der Geer AAE. Paradise lost: Evidence for a devastating metabolic bone disease in an insular Pleistocene deer. International journal of paleopathology 524, 213-226; DOI: 10.1016/j.ijpp.2018.12.003

    This is the first evidence of a metabolic bone disease causing an extreme level of destructive pathology in an insular fossil deer. We analysed skeletal pathologies in a Late Pleistocene endemic deer from the Mavromouri caves of Crete. The bones were evaluated macroscopically, and measurements were made of morphometric characteristics of limb long bones. Representative bone specimens were examined radiographically and histologically. We found macroscopic hallmarks of severe loss of bone mass and increased porosity. The long bones were brittle, some of them having thin cortices, and others reduction of medullary cavities that contain dense Haversian tissue. The flat bones were spongy and fragile. Erosions of the metaphyses and articular surfaces were noted. Histological findings included: sub-periosteal resorption; loss of lamellar bone; enlargement of vascular canals; and remodeling of cortical bone. Two types of fibrous osteodystrophy were recognized in skeletal remains, subostotic and hyperostotic. We conclude that the deer populations of Mavromouri caves were affected by severe metabolic bone disease, likely nutritional secondary hyperparathyroidism. We hypothesize a multifactorial cause, including overgrazing, flora senescence, soil mineral deficiencies, and a prolonged period of climate extremes, degrading the Cretan deer habitat. Unfortunately, the lack of absolute chronometric dates for the site limits potential linking with the prevailing environmental conditions.
    Key words: bone remodeling, Candiacervus, Mavromouri, Nutritional Secondary Hyperparathyroidism, osteophagia, palaeohistology
    [ScienceDirect]


  • 2018 van der Geer AAE. Uniformity in variety: antler morphology and evolution in a predator-free environment.
    Palaeontologia Electronica 21.1.9A 1-31; DOI: 10.26879/834

    The Late Pleistocene mammal fauna of Crete was impoverished, as typical for oceanic islands, and consisted only of deer, dwarf elephants, an otter, a shrew and giant mice. Dwarf deer (Candiacervus spp.) were the dominant endemic herbivorous species. Here, I describe the adult antler morphology of this deer. Antler variety appears to be remarkably large, yet a few concise morphological groups without intermediate forms can be recognized, likely representing separate species. Antler variety is not a product of random variation induced by ecological release in a predator-free environment. Three new species are described here (Candiacervus spp. nov.), differing in antler and skull morphology, and the diagnosis of existing species (C. ropalophorus, C. rethymnensis) is emended based on new material. Antler variation can be explained by two evolutionary trends: showiness versus a classic fighting type. Divergence is driven and accelerated by intra-specific competition among males. The classic type is best explained as a result of allometric down-scaling during dwarfism. The display type is best explained as a result of restructuring of antler bauplan (simplification and extreme elongation of the main beam). Under predator-free scenarios, deer have the potential to evolve antler morphologies and behavioural changes unknown on the mainland.
    Key words: Candiacervus, endemic deer, new species, adaptive radiation
    [Palaeontologia Electronica Free Access]


  • 2018 Kouvari M, van der Geer AAE. Biogeography of extinction: the demise of insular mammals from the Late Pleistocene till today.
    Palaeogeography, Palaeoclimatology, Palaeoecology 505, 295-304; DOI: 10.1016/j.palaeo.2018.06.008

    Extinction, speciation and immigration are the main factors shaping patterns of biodiversity on islands. In particular, the impact of the Late Pleistocene-Holocene extinction wave had a strong impact on the megafauna. Here we investigate the relationship between extinctions of insular endemic mammal species and their body mass, the size of the island and the first human arrival to the archipelago. Our data on islands worldwide show that megafauna was hit hard indeed. All islands lost their heaviest mammal species, whereas maximum surviving mammalian body size differs per archipelago, ranging from heavier than 100 kg (Philippines) to below 100 g (Canaries) and no surviving native mammals on the Galapagos. Although the number of extinctions is highest on larger islands, in line with predictions following from the species-area relationship, the percentage in relation to total number of endemic species is the lowest. Major part (almost 80 percent) of extinctions of insular endemics took place after the first human arrival, with the highest percentages during the Late Pleistocene (34.5 percent) and the Modern Era (31 percent). This indicates an increased rate of extinctions in the Modern Era, considering the substantially longer time span of the former period. Increased globalisation with introductions of alien species in combination with substantial anthropogenic habitat alteration likely underlies this pattern. Whether these extinction waves follow a fast or slow scenario (also known as blitzkrieg versus sitzkrieg scenarios) remains unclear, but the gradual increase in extinctions through the Holocene, with a peak (31 percent) in the last 500 years, is suggestive of a slow scenario.
    Key words: Holocene, human impact, island extinctions, megafaunal extinction
    [ScienceDirect]


  • 2018 van der Geer AAE, Lyras GA, Mitteroecker P, MacPhee RDE. From Jumbo to Dumbo: cranial shape changes in elephants and hippos during phyletic dwarfing.
    Evolutionary Biology 45 (3), 303-317; DOI: 10.1007/s11692-018-9451-1

    extinct dwarf species that display up to 98 percent decrease in body size compared to probable ancestral sources. In addition to differences in body mass, skulls of these species consistently display distinctive morphological changes, including major reduction of pneumatised areas in dwarf elephants and shortened muzzles in dwarf hippos. Here we build on previous studies of island dwarf species by conducting a geometric morphometric analysis of skull morphology and allometry in target taxa, living and extinct, and elaborate on the relation between skull size and body size. Our analysis indicates that skull size and body size within terrestrial placental mammals scale almost isometrically (PGLS major axis slope 0.906). Furthermore, skull shape in dwarf species differed from both their ancestors and the juveniles of extant species. In insular dwarf hippos, the skull was subject to considerable anatomical reorganisation in response to distinct selection pressures affecting early ontogeny. By contrast, skull shape in adult insular dwarf elephants can be explained well by allometric effects; selection on size may thus have been the main driver of skull shape in dwarf elephants. We suggest that a tightly constrained growth trajectory, without major anatomical reorganization of the skull, allowed for flexible adaptations to changing environments and was one of the factors underlying the evolutionary success of insular dwarf elephants.
    Key words: evolution, geometric morphometrics, insular dwarf species, pedomorphism, Pleistocene
    [SpringerLink]


  • 2018 van der Geer AAE, Lyras GA, Volmer R Insular dwarfism in canids on Java (Indonesia) and its implication for the environment of Homo erectus during the Early and earliest Middle Pleistocene.
    Palaeogeography, Palaeoclimatology, Palaeoecology early view; DOI: 10.1016/j.palaeo.2018.07.009

    Several canid fossils, which were originally discovered and described in the early 20th century, are known from Early and earliest Middle Pleistocene of Java (Indonesia), and are often described as forms of Cuon, the dhole or red dog of Asia. In this paper we revised the taxonomy and relative age of these Javanese canid fossils in light of recent developments in the taxonomy and phylogeny of Canidae, and new insights in the evolution of island mammals. We show that Cuon was absent during the Early and earliest Middle Pleistocene while the large-sized Xenocyon (previously described for Java as Megacyon), a large and hypercarnivorous wolf-like canid, was present in the Early Pleistocene and replaced by the small-sized Xenocyon (previously Mececyon) during the earliest Middle Pleistocene. The latter is probably a dwarf form that in due time evolved on the island from the larger form of the preceding period. The change in body size of Xenocyon on Java over time is likely the effect of increased competition within the carnivore guild within the restricted boundaries of the island. Simultaneously with a pronounced body size shift, a dietary shift from large-sized prey to much smaller prey must have taken place in order to meet energetic constraints (in plain language: large wolfs cannot survive eating only small rats). The degree of endemism of terrestrial mammals of the earliest Middle Pleistocene horizon of the site Trinil, which has also yielded Homo erectus fossils (the famous Pithecanthropus fossils), indicates that during this period, Java was marginally isolated which allowed for a corridor dispersal to the island with subsequent vicariance. The nature and degree of isolation may have been similar to that of Late Pleistocene Sicily, but of a longer duration, given the higher degree of dwarfism of the stegodon, antilope and canid. The following continentalisation enabled the invasion by mainland terrestrial mammals, as is seen in younger layers at Trinil, and eventually by Homo sapiens and Cuon in the Late Pleistocene / Holocene of Java.
    Key words: carnivore guild, island dwarfism, Mececyon, Megacyon, Trinil H.K., Xenocyon
    [Science Direct]


  • 2018 Strasser TF, Murray SC, van der Geer A, Kolb C, Ruprecht LA Jr Palaeolithic cave art from Crete, Greece.
    Journal of Archaeological Science: Reports 18, 100-108; DOI: 10.1016/j.jasrep.2017.12.041

    The earliest figural art known from Greece is dated to the Neolithic period (ca. 8,5 to 5 thousand years ago). A recent study of the petroglyphs at Asphendou Cave on the island of Crete, however, suggests that such art has a much longer history in the Aegean basin. First published over forty years ago, the debate concerning the petroglyphs' age has lain dormant for decades. In light of technological advances in digital imaging and recent archaeological and palaeontological discoveries on the island we re-assess the dating of the petroglyphs and prove that some were made in the Late Pleistocene, or Upper Palaeolithic. Comparison of the iconography to fossil data demonstrates that an extinct endemic deer (Candiacervus) is represented at Asphendou Cave. This is the earliest figural art yet discovered in Greece
    Key words: Palaeolithic cave art, petroglyphs, photogrammetry, extinct island fauna
    [Science Direct Open Access]


  • 2018 van der Geer AAE, Lomolino MV, Lyras G 'On being the right size' - Do aliens follow the rules?
    Journal of Biogeography 45 (3), 515-529; DOI: 10.1111/jbi.13159

    Aim: To assess whether mammalian species introduced onto islands across the globe have evolved to exhibit body size patterns consistent with the island rule, and to test an ecological explanation for body size evolution of insular mammals.
    Location: Islands worldwide.
    Methods: We assembled data on body mass, geographical characteristics (latitude, maximum elevation) and ecological communities (number of mammalian competitors, predators and prey) for 385 introduced populations across 285 islands, comprising 56 species of extant, non-volant mammals. We used linear regression, ANCOVA and regression tree analyses to test whether introduced populations of mammals exhibit the island rule pattern, whether the degree of body size change increased with time in isolation and whether residual variation about the general trend can be attributed to the geographical and ecological characteristics of the islands.
    Results: Introduced populations follow the predicted island rule trend, with body size shifts more pronounced for populations with greater residence times on the islands. Small mammals evolved to larger body sizes in lower latitudes and on islands with limited topographic relief. Consistent with our hypothesis on the ecology of evolution, body size of insular introduced populations was influenced by co-occurring species of mammalian competitors, predators and prey.
    Conclusion: The island rule is a pervasive pattern, exhibited across a broad span of geographical regions, taxa, time periods and, as evidenced here, for introduced as well as native mammals. Time in isolation impacts body size evolution profoundly. Body size shift of introduced mammals was much more pronounced with increasing residence times, yet far less than that exhibited by native, palaeo-insular mammals (residence times > 10,000 years). Given the antiquity of many species introductions, it appears that much of what we view as the natural character and ecological dynamics of recent insular communities may have been rendered artefacts of ancient colonizations by humans and commensals.
    Key words: Anthropocene, body size evolution, competition, Holocene, introduced species, invasive species, island biogeography, island rule, meta-analysis
    [Wiley Online Library, Open Access]


  • 2018 van der Geer AAE Changing invaders: trends of gigantism in insular introduced rats.
    Environmental Conservation 45, 203-211; DOI: 10.1017/S0376892918000085

    The degree and direction of morphological change in invasive species with a long history of introduction are insufficiently known for a larger scale than the archipelago or island group. Here, I analyse data for 105 island populations of Polynesian rats, Rattus exulans, covering the entirety of Oceania and Wallacea to test whether body size differs in insular populations and, if so, what biotic and abiotic features are correlated with it. All insular populations of this rat, except one, exhibit body sizes up to twice the size of their mainland conspecifics. Body size of insular populations is positively correlated with latitude, consistent with thermoregulatory predictions based on the rule of Bergmann, according to which individuals in colder regions are larger and heavier than individuals of the same species in warmer regions. Body size is negatively correlated with number of co-occurring mammalian species, confirming an ecological hypothesis of the island rule.The largest rats are found in the temperate zone of NewZealand, as well as on mammalian species-poor islands of Polynesia and the Solomon Islands. Carnivory in the form of predation on nesting seabird colonies seems to promote 1.4- to 1.9-fold body size increases.
    Key words: body size evolution, invasive species, islands, island rule, kiore, Rattus exulans, Polynesia
    [Cambridge University Press]


  • 2017 van den Hoek Ostende LW, van der Geer AAE, Wijngaarden CL Why are there no giants at the dwarves feet? Insular micromammals in the eastern Mediterranean.
    Quaternary International 445, 269-278; DOI: 10.1016/j.quatint.2016.05.007

    The eastern Mediterranean has yielded some textbook examples of insular evolution among large mammals such as the world's smallest hippopotamus and mammoth. By contrast, gigantism among small mammals is limited, with the exception of the early Pleistocene murid Kritimys from Crete. The large body size of insular rodents can be related to an energetically advantageous position at the slow end of the mammalian fast-slow continuum. In order to test the hypothesis that the development of gigantism was hampered by the harsher climatic conditions of the middle and late Pleistocene, we constructed a dataset of endemic murids and cricetids from islands all over the world. Upto the middle Pleistocene, giant rodents can be found all over the world. However, in the later part of the Pleistocene and Holocene, these are only found at lower latitudes, suggesting that indeed the harsher conditions of the north no longer allowed insular rodents to develop the slow life-strategy that previously could still be achieved at these latitudes.
    Key words: Island evolution, Crete, life strategies, gigantism, Pleistocene, paleontology
    [ScienceDirect]


  • 2017 Van der Geer AAE, Lomolino M, Lyras GA 'Island Life' before man: biogeography of palaeo-insular mammals.
    Journal of Biogeography 44, 995-1006; DOI: 10.1111/jbi.12857.

    Our aim is to assess the relative contributions of colonization, speciation and human activities on species richness (S) of mammalian communities among oceanic islands world-wide. To this aim, we compiled species lists and compared species-area and species-isolation relationships for mammalian taxa of 36 islands over three stages of community development during the late Pleistocene and Holocene: at colonization, or founding (Sf); after in situ speciation, but before colonization by humans (Ss); and during the Anthropocene (SA), that is, following human colonization and subsequent extinctions and species introductions. We used regression and correlation analyses to compare Sf and Ss patterns to assess the impact of speciation on the native assemblages, and compared these patterns to those expected by island biogeography theory (largely based on patterns for extant insular faunas). We then compared patterns for Ss and SA to assess impacts of human activities on insular community structure. Although patterns for Sf were consistent with those expected based on island biogeography theory (Sf increasing with area and decreasing with isolation), patterns for Ss were quite anomalous, with uncharacteristically steep loglog slopes (high z-values) of the species-area relationship, and no significant influence of isolation on Ss. Analyses based on contemporary assemblages (SA)indicated that human activities have rendered native assemblages highly depauperate, while anthropogenic introductions have inflated richness far above Ss on all but the largest islands. Long-standing models of island biogeography may prove inadequate unless their conceptual domains are expanded to include the effects of all three fundamental, biogeographical processes (immigration, extinction and speciation), the impact of human activities on each of these processes, and the likelihood that, at least for very large and isolated islands, a long-term equilibrium among these processes is seldom achieved.
    Key words: Anthropocene, extinction, island biogeography, mammals, palaeobiology, Pleistocene, speciation, species-area relationship (SAR), species-isolation relationship (SIR)
    [Wiley Online Library]


  • 2017 Van der Geer AAE, Galis F. High incidence of cervical ribs indicates vulnerable condition in Late Pleistocene woolly rhinoceroses.
    PeeerJ 5(8):e3684; DOI: 10.7717/peerj.3684

    Mammals as a rule have seven cervical vertebrae, a number that remains remarkably constant. Changes of this number are associated with major congenital abnormalities (pleiotropic effects) that are, at least in humans, strongly selected against. Recently, it was found that Late Pleistocene mammoths (Mammuthus primigenius) from the North Sea have an unusually high incidence of abnormal cervical vertebral numbers, approximately ten times higher than that of extant elephants. Abnormal numbers were due to the presence of large cervical ribs on the seventh vertebra, indicating a homeotic change from a cervical rib-less vertebra into a thoracic rib-bearing vertebra. The high incidence of cervical ribs indicates a vulnerable condition and is thought to be due to inbreeding and adverse conditions that may have impacted early pregnancies in declining populations. In this study we investigated the incidence of cervical ribs in another extinct Late Pleistocene megaherbivore from the North Sea and the Netherlands, the woolly rhinoceros (Coelodonta antiquitatis). We show that the incidence of abnormal cervical vertebral numbers in the woolly rhinoceros is unusually high for mammals (15,6 percent, n = 32) and much higher than in extant Rhinoceratidae (0 percent, n = 56). This indicates that woolly rhinoceros lived under vulnerable conditions, just like woolly mammoths. The vulnerable condition may well have contributed to their eventual extinction.
    [PeerJ Open Access]


  • 2017 Van der Geer AAE Reply to Mazza, P. et al.: Observations on the postcranial anatomy of Hoplitomeryx (Mammalia, Ruminantia, Hoplitomerycidae) from the Miocene of the Apulia Platform (Italy).
    Palaeontographica Abteilung A 310 (1-2), 1-4; DOI: 10.1127/pala/2017/0074

    In 2014, I revised the taxonomy of the Late Miocene ruminants of the Apulia Platform (central and southeastern Italy), based on the morphology of the postcranial material (size, shape, congruency of joint surfaces), and that of cranial and dental remains of material ascribed to the genus Hoplitomeryx. The material originates from two widely separated sites: Scontrone (Abruzzo, central Italy) and Gargano (Apulia, southern Italy), with a geological age difference of about 2 to 3 million years. Originally, the genus Hoplitomeryx was defined for Gargano with one species, H. matthei, and several morphotypes (Leinders 1984). Later, Mazza & rustioni (2011) recognized the latter species also at Scontrone based on the presence of orbital appendages and described five additional new Hoplitomeryx species for Scontrone, which they extrapolated to Gargano. However, I attributed the ruminant material from Scontrone to a new genus, Scontromeryx, whereas I retained the material from Gargano in Hoplitomeryx. I further described a new species for Scontromeryx(S. mazzai) to accommodate the material previously ascribed to H. matthei, and three new species for Hoplitomeryx (H. devosi, H. macpheei, H. kriegsmani) for Gargano. I retained all five species described for Scontrone (Mazza & rustioni 2011) but moved them to Scontromeryx. My revision thus recognizes four species of Hoplitomeryx for Gargano and six species of Scontromeryx for Scontrone. I further argued that the two localities need not have been connected at any time in geological history. Mazza et al. (2016) disagree with my revision and I hereby took the opportunity to reply to some of their arguments.
    Key words: Gargano, Scontrone
    [Schweizerbart publishing]


  • 2016 Van der Geer AAE, van den Bergh G, Lyras GA, Prasetyo UW, Due RA, Setiyabudi E, Drinia H. The effect of area and isolation on insular dwarf proboscideans.
    Journal of Biogeography 43, 1656-1666; DOI: 10.1111/jbi.12743

    We investigated the hypothesis that insular body size of fossil elephants is directly related to isolation and surface area of islands worldwide. To this aim, we assembled data on the geographical characteristics (area and isolation) of islands and body size evolution of palaeo-insular species for 22 insular species of fossil elephants across 17 islands. Our results support the generality of the island rule in the sense that all but one of the elephants experienced dwarfism on islands. The smallest islands generally harbour the smallest elephants. We found no support for the hypothesis that body size of elephants declines with island isolation. Body size is weakly and positively correlated with island area for proboscideans as a whole, but more strongly correlated for Stegodontidae when considered separately. Average body size decrease is much higher when competitors are present. Body size in insular elephants is not significantly correlated with the isolation of an island. Surface area, however, is a significant predictor of body size. The correlation is positive but relatively weak; c. 23% of the variation is explained by surface area. Body size variation seems most strongly influenced by ecological interactions with competitors, possibly followed by time in isolation. Elephants exhibited far more extreme cases of dwarfism than extant insular mammals, which is consistent with the substantially more extended period of deep geological time that the selective pressures could act on these insular populations.
    Key words: Elephas, fossil record, insularity, island biogeography, island rule
    [PDF]


  • 2016 Volmer R, Hertler C, van der Geer AAE. Niche overlap and competition potential among tigers (Panthera tigris), sabertoothed cats (Homotherium ultimum, Hemimachairodus zwierzyckii) and Merriam's Dog (Megacyon merriami) in the Pleistocene of Java.
    Palaeogeography, Palaeoclimatology, Palaeoecology 441, 901-911. DOI: 10.1016/j.palaeo.2015.10.039.

    Highlights: Late Pleistocene tigers of Java belong to the largest known tigers; Shifts in body masses of tigers are probably caused by competition; Tigers on Java had highest competition potential with Merriam's Dog; Homotherium ultimum had the lowest competition protential with tigers; New regressions for body mass and prey mass reconstruction for large carnivores were calculated.
    Key words: carnivores, body mass, ecological character displacement, prey mass spectrum, Sangiran, Southeast Asia
    [ScienceDirect]


  • 2015 Kolb C, Scheyer TM, Veitschegger K, Forasiepi AM, Amson E, van der Geer AAE, van den Hoek Ostende LW, Hayashi S, Sanchez-Villagra MR. Mammalian bone palaeohistology: a survey and new data with emphasis on island forms.
    PeerJ; DOI 10.7717/peerj.1358

    Bone tissue and vascularisation types correlate with several biological variables such as ontogenetic stage, growth rate, and ecology. Mammalian bone displays a large variety of bone tissues and vascularisation patterns ranging from lamellar or parallel-fibred to fibrolamellar or woven-fibred bone, depending on taxon and individual age. Here we systematically review the knowledge and methods on cynodont and mammalian bone microstructure as well as palaeohistology. We present new data on the bone microstructure of two extant marsupial species and of several extinct continental and island placental mammals.
    Key words: Mammals, palaeohistology, island evolution, bone tissue, Mikrotia, Paraceratherium, Hippopotamus minor, Leithia, Sinomegaceros, Prolagus
    [PDF Open Access]


  • 2015 Van der Geer AAE, Anastasakis G, Lyras GA. If hippopotamuses cannot swim, how did they colonize islands: a reply to Mazza.
    Leithaia 48, 147-150. DOI: 10.1111/let.12095

    How hippopotamuses managed to cross tens or even hundreds of kilometres of open sea to islands and why they did so are, as Mazza (2014) formulates it, challenging problems. The formidable body mass, barrel-shaped build and the relatively stocky, short limbs do not look as those of an apt swimmer. Furthermore, hippopotamuses have been described as bottom-walkers rather than surface swimmers (for details see below). Yet, the fossil record proves their existence on six islands during the Pleistocene.Mazza (2014, p. 2) suggests they were on ‘probably most other Mediterranean islands’, but there is no evidence to support this claim, despite the abundant fossil record from Sardinia, Corsica, the Balearics, Tilos, Rhodes and Karpathos. Arguing that hippopotamuses cannot swim in open sea, Mazza postulates that in all of these cases the only remaining option for colonization is by land bridge, either fully exposed or only one or two metres deep. If Mazza is right, and hippopotamuses cannot survive overseas dispersal, the available geological evidence should be reconsidered or an alternative explanation has to be looked for. There are some inconsistencies in Mazza’s reasoning, which we address below in light of effective collaboration among biologists, palaeontologists, geologist and biogeographers as recommended by Mazza (2014).
    Key words: dwarf hippos, Crete, Cyprus, Madagascar, land bridges, overseas dispersal, Pleistocene, swimming
    [Wiley Online Library] [PDF on Academia ] [PDF on ResearchGate]


  • 2014 Van der Geer AAE, Lyras GA, MacPhee RDE, Lomolino M, Drina H. Mortality in a predator-free insular environment: the extinct dwarf deer from Crete.
    American Museum Novitates 3807, 29 pp. DOI: 10.1206/3807.1

    Age-graded fossils of Pleistocene endemic Cretan deer (Candiacervus spp.) reveal unexpectedly high juvenile mortality similar to that reported for extant mainland ruminants, despite the fact that these deer lived in a predator-free environment and became extinct before any plausible date for human arrival. Age profiles show that deer surviving past the fawn stage were relatively long-lived for ruminants, indicating that high juvenile mortality was not an expression of their living a 'fast life'. Although the effects on survivorship of such variables as fatal accidents, starvation, and disease are difficult to gauge in extinct taxa, the presence of extreme morphological variability within nominal species/ecomorphs of Candiacervus is consistent with the view that high juvenile mortality can function as a key innovation permitting rapid adaptation in insular contexts.
    Key words: Candiacervus, juvenile mortality, Pleistocene, life history tables, longevity, survivorship curves
    [PDF AMNH Digital Repository]


  • 2014 Van der Geer AAE. Systematic revision of the family Hoplitomerycidae Leinders, 1984 (Artiodactyla: Cervoidea), with the description of a new genus and four new species.
    Zootaxa 3847 (1), 1-32. DOI: 10.11646/zootaxa.3847.1.1

    Six species of the cervoid genus Hoplitomeryx are currently recognized from the Late Miocene sites of Gargano and Scontrone, in Italy: H. matthei Leinders, 1984, H. apruthiensis Mazza & Rustioni, 2011, H. apulicus Mazza & Rustioni, 2011, H. falcidens Mazza & Rustioni, 2011, H. magnus Mazza & Rustioni, 2011, and H. minutus Mazza & Rustioni, 2011. These species are interpreted as members of an anagenetic series in these two localities, which are considered as part of the same bioprovince but with different geological ages. Comparative analysis of postcranial, dental, and cranial material from Hoplitomerycidae resulted in the reinterpretation of this current taxonomic arrangement. Two distinct genera can be distinguished. The new genus Scontromeryx is restricted to Scontrone (Early Tortonian) and is characterised by the presence of second upper and lower premolars and the absence of a nasal (median) horn. Hoplitomeryx is restricted to Gargano (Middle and/or Late Tortonian), and is characterized by the loss of the second premolar and presence of a nasal horn. Both genera are characterized by orbital appendages in some species, but the morphology of these appendages differs between the genera. Six species can be recognized for Scontromeryx gen. n.: S. minutus (type species), S. falcidens, S. apulicus, S. apruthiensis, S. magnus (new combinations) and the newly described S. mazzai sp. n. Hoplitomeryx is represented by the H. matthei (type species) and 3 newly described species H. devosi sp. n., H. macpheei sp. n. and H. kriegsmani sp. n.. These two multispecies assemblages are best explained as independent adaptive radiations with the two genera as sister taxa. There is no evidence that the two localities were connected during the Late Miocene.
    Key words: Gargano, Hoplitomeryx, insularity, Late Miocene, Scontrone, Scontromeryx
    [Publisher preview]


  • 2014 Van der Geer AAE. The impact of isolation: Evolutionary processes in Hoplitomeryx.
    Ph.D. thesis, Rijksuniversiteit Utrecht.

    Hoplitomeryx is an example of island evolution under extremely long isolation. Its evolutionary history agrees with that of other insular species. This includes both the pattern of its body size evolution (adaptive radiation) as well as the evolution of some of its characteristic traits. Hoplitomeryx lived on the Late Miocene palaeo-island of Gargano, today part of mainland southern Italy. The genus Hoplitomeryx is mainly characterised by four orbital horns, a nasal (median) horn, sabre-like upper canines and a closed metatarsal gully.
    Insular mammals typically grow larger or smaller depending on a combination of factors. The trend is not only much more pronounced in the fossil record, related to time in isolation, but may also show fluctuations through time when factors change. on the other hand displays both smaller and larger species in a multispecies assemblage (adaptive radiation). Body size does not converge here towards a hypothetical optimal body size but diverges instead, driven by ecological release, character displacement and niche partitioning. The largest species have a suboptimal build with their very slender, fragile long limb bones with narrow articulation areas, very unlike the massive limb bones with broad articulation areas of mainland large deer of similar wither's height. Such vulnerable species likely would not survive under high-predation regimes. Its extraordinary long limb bones suggest a dietary niche of otherwise unreachable branches and leaves.
    Key words: adaptive radiation, body mass evolution, cladogenesis, insularity, Late Miocene, Mediterranean Islands, Neogene
    [PDF Igitur Repository]


  • 2014 Van der Geer AAE, Lyras GA, van den Hoek Ostende LW, de Vos J, Drina H. A dwarf elephant and a rock mouse on Naxos (Cyclades, Greece) with a revision of the palaeozoogeography of the Cycladic Islands during the Pleistocene.
    Palaeogeography, Palaeoclimatology, Palaeoecology 404: 133-144. DOI: 10.1016/j.palaeo.2014.04.003

    During the Late Pleistocene, Naxos and adjacent areas, including Delos and Paros, constituted a mega-island, here referred to as palaeo-Cyclades. The extensive low-lying plainswith lakes and rivers provided a suitable habitat for elephants. Due to long-term isolation from the mainland and mainland populations, these elephants evolved miniature size. The species found on Naxos had a body size of about ten percent of that of the mainland ancestor, Palaeoloxodon antiquus. During the glacial periods of the Late Pleistocene, P. antiquus may have migrated eastwards and southwards in search of better conditions and reached the islands. The dwarf species of the various Southern Aegean islands (e.g. Crete, Tilos, Rhodos, palaeo-Cyclades) are each the result of independent colonisation events. The very small size of the Naxos species respective to the dwarf elephants from Crete is explained as due to the lack of competitors. The only other elements of the contemporaneous fauna were a rock mouse (Apodemus cf. mystacinus) and a shrew (Crocidura sp.). Submergence of the area, climate change, volcanism, hunting by humans or a combination of these factors during the terminal Pleistocene may have caused the extinction of this endemic fauna.
    Key words: Mediterranean, Naxos, Palaeoloxodon lomolinoi
    [PDF at Publisher site] [PDF at ResearchGate (for members only)]


  • 2014 Van der Geer AAE. Parallel patterns and trends in functional structures in island mammals.
    Integrative Zoology 9: 167-182. DOI: 10.1111/1749-4877.12066

    Endemic mammalian species on islands are generally known to have followed a different evolutionary pathway than their mainland relatives. General patterns, such as body size trends, have been described regularly. However, most island mammal species are unique and each of them is adapted to a specific local niche as part of an equally specific ecological assemblage. Therefore, comparing island species across taxa, islands and time is inherently dangerous without understanding the adaptational value of the studied feature in the compared taxa and without taking the ecological setting of the taxa into account. In this contribution, general and recurring patterns are described per taxon. Some features, like body mass change and sturdy limbs, are relatively general, whereas most features, like bone fusions and change of orbital axis, occur only in a very few taxa. Some features are even contradictory, such as brain size and degree of hypsodonty, with each taxon having its own particular design. In conclusion, general patterns are more often than not just trends and need to be applied with caution.
    Key words: body proportions, fossil record, insularity, island rule, paleo -insular mammals, Pleistocene
    [Wiley Online Library] [PDF (for Academia members only]


  • 2013 Van der Geer AAE, Dermitzakis M. Caves and fossils: Palaeontology in Greek caves and fissures.
    In: Mavridis F, Jensen JT (eds.) Stable Places and Changing Perceptions: Cave Archaeology in Greece, Chapter 3, pp.83-98. BAR International Series 2558. Archaeopress, Publishers of British Archaeological Reports, Oxford. ISBN 9781407311791.

    Caves constitute one of the most important sources for fossilized remains of life of the past in Greece and adjacent karstic areas. The reason is that caves provide a uniquely favorable environment for the preservation of fossil animal and plant remains. First of all, caves have a uniform and stable temperature and humidity. They are essentially closed environments, buffered within a huge mass of isolating rock. Therefore, they can preserve remains of past life for thousands of years, as if in a natural refrigerator. Secondly, they are often sealed off for extensive periods of time, due to collapse of an entrance or because of complete filling with sediments. The preserved remains are thus undisturbed and safeguarded against damage from outside, as if in a natural safe or treasure box. The fact that caves often have a time limit (a beginning when they are first formed and an end when they are filled with sediment or collapsed) makes caves even more important for palaeontology as they provide a snapshot of geological time, undisturbed by previous or following life forms.
    [Link to the book]


  • 2013 Van der Geer AAE, Lyras GA, Lomolino M, Palombo MR, Sax D. Body size evolution of palaeo-insular mammals: temporal variations and interspecific interactions.
    Journal of Biogeography 40: 1440-1450. DOI: 10.1111/jbi.120462.

    We investigated the hypothesis that body size evolution of mammals is strongly influenced by ecological interactions, resulting in evolutionary divergence in body size in species-rich (e.g., mainland) biotas, and convergence on the size of intermediate but absent species in species-poor (e.g., insular) biotas. In order to do so, we assembled data on temporal variation in body size of palaeo-insular mammals and associated variation in ecological characteristics (colonization or extirpation of mammalian competitors and predators) for 19 species of fossil, non-volant mammals across 4 large (>3640 km2) islands ranging between the Late Miocene and Holocene in the Mediterranean area. These are the only fossil species for which fine-detailed time series are available at present. Our results are consistent with predictions based on an ecological interactions hypothesis of body size evolution. Following colonization (or first appearance in the insular fossil record) small mammals (such as mice, shrews, and pikas) tended to increase in body size. These trends, however, ceased or were reversed following colonization of the focal islands by mammalian predators or competitors. Thus, While body size evolution is likely influenced by a variety of characteristics of the focal islands (e.g., climate, area, isolation and habitat diversity) and species (e.g., diet, resource requirements and dispersal abilities), temporal trends for palaeo-insular mammals indicated that the observed trends for any particular species, island and climatic regime may be strongly influenced by interactions among species. Ultimately, invasion of a competitor often leads to the extinction of the native, insular species.
    Key words: biological invasions, body size fluctuations, competition, extinct species, fossil record, island evolution, island rule, mammals, Mediterranean palaeo-islands, predation.
    [Wiley Online Library] [full PDF]


  • 2013 Lomolino MV, van der Geer AAE, Lyras G, Palombo MR, Sax D, ROzzi R. Of mice and mammoths: generality and antiquity of the island rule.
    Journal of Biogeography 40: 1427-1439. DOI: 10.1111/jbi.12096.

    We assessed the generality of the island rule in a database comprising 1593 populations of insular mammals (439 species, including 63 species of fossil mammals), and tested whether observed patterns differed among taxonomic and functional groups. To do do, we measured museum specimens (fossil mammals) and reviewed the literature to compile a database of insular animal body size (Si = mean mass of individuals from an insular population divided by that of individuals from an ancestral or mainland population, M). Then used linear regressions to investigate the relationship between Si and M, and ANCOVA to compare trends among taxonomic and functional groups. We found that this Si was significantly and negatively related to the mass of the ancestral or mainland population across all mammals and within all orders of extant mammals analysed, and across palaeo-insular (considered separately) mammals as well. Insular body size was significantly smaller for bats and insectivores than for the other orders studied here, but significantly larger for mammals that utilized aquatic prey than for those restricted to terrestrial prey. Our main conclusions are that the island rule appears to be a pervasive pattern, exhibited by mammals from a broad range of orders, functional groups and time periods. There remains, however, much scatter about the general trend; this residual variation may be highly informative as it appears consistent with differences among species, islands and environmental characteristics hypothesized to influence body size evolution in general. The more pronounced gigantism and dwarfism of palaeo-insular mammals, in particular, is consistent with a hypothesis that emphasizes the importance of ecological interactions (time in isolation from mammalian predators and competitors was 0.1 to > 1.0 Myr for palaeo-insular mammals, but < 0.01 Myr for extant populations of insular mammals). While ecological displacement may be a major force driving diversification in body size in high-diversity biotas, ecological release in species-poor biotas often results in the convergence of insular mammals on the size of intermediate but absent species.
    Key words: body size, dwarfism, evolution, fossils, gigantism, island rule, islands, mammals
    [Wiley Online Library Free Access]


  • 2012 Lomolino MV, Sax DF, Palombo MR, van der Geer AAE. Of mice and mammoths: evaluations of causal explanations for body size evolution in insular mammals.
    Journal of Biogeography 39: 842-854.

    We investigated the hypothesis that insular body size of mammals results from selective forces whose influence varies with characteristics of the focal islands and the focal species, and with interactions among species (ecological displacement and release) on islands world-wide. Our results, based on regression tree analyses, support the hypothesis that body size evolution of insular mammals is influenced by a combination of selective forces whose relative importance and nature of influence are contextual. While there may exist a theoretical optimal body size for mammals, in general, the optimum for a particular insular population varies in a predictable manner with characteristics of the islands and the species, and with interactions among species. This study did, however, produce some unanticipated results that merit further study - patterns associated with Bergmanns rule are amplified on islands, and body size of small mammals appears to peak at intermediate and not maximum values of latitude and island isolation.
    Key words: area, body size, climate, evolution, island rule, islands, isolation, latitude, mammals, regression trees
    [Wiley Online Library] [PDF]


  • 2011 Van der Geer AAE. Seventeen capsules and sidebars on various themes within Era 1 (Beginnings of Human Society).
    In: World History Encyclopedia, 20 vols plus intro vol, general editor Alfred J.Andrea. Santa Barbara, ABC-Clio, ISBN 978-1-851-09929-0.

    The human family lineage: 8 million years ago to 20,000 years ago (pp 38-41, main capsule, overview), The Late Miocene climate and environments of central, eastern, and southern Africa (page 44, main capsule), Ardipithecus ramidus (page NA), The footprints at Laetoli and the significance of walking upright (page 50, main capsule), Australopithecus afarensis (pp 51-53, main capsule), The importance of Hadar: the discovery of 'Lucy' (page 52, sidebox), Australopithecus africanus (pp 54-55, main capsule), Swartkrans and the Taung child (page 54, sidebox), The robust australopithecines: aethiopocus, robustus and boisei (pp 56-57, main capsule), Homo erectus in Asia (pp 66-68, main capsule), The odyssey of the Zhoukoudien fossils (page 67, sidebox), Homo antecessor at Atapuerca, Spain (page 68, sidebox), The lifeways of Homo erectus (pp 110-111, main capsule), The adaptive radiation of Homo erectus (pp 192-193, main capsule), What happened to Homo erectus in Asia? (pp 201-201, main capsule), Molecular biology and the Eve Hypothesis (page 79, sidebox), Tool making by our closest primate relatives (page 331, main capsule).

    This Encyclopedia is an unprecedented academic undertaking reflecting an extraordinary new vision of world history, this landmark multivolume encyclopedia focuses on specific themes of human development across cultures era by era, providing the most in-depth, expansive presentation available of the development of humanity from a global perspective. Well-known and widely respected historians worked together to create and guide the project in order to offer the most up-to-date visions available. In the fields of history and history education, there is a growing trend toward focusing on the big picture, a history unlimited by borders focusing less on dates and countries and more on the defining themes of modern life. [Publisher's site]


  • 2011 Van der Geer AAE. Ten capsules and sidebars on South Asia within Era 3 (Classical Traditions 1000 B.C.E.-300 C.E.), Era 4 (Expanding Regional Civilizations 300-1000) and Era 5 (Intensified Hemispheric Interactions 1000-1500).
    In: World History Encyclopedia, 20 vols plus intro vol, general editor Alfred J.Andrea. Santa Barbara, ABC-Clio, ISBN 978-1-851-09929-0.

    Early popular literature in India, The origin of drama, The Pala dynasty, The Pala School of Art, The export of Pala art, Early medieval South Asian art, The Rajputs, warriors by caste, Rajput origins, Early medieval industries, Gujarat, a centre of commerce.
    [Publisher's site]


  • 2011 Van der Geer AAE, Lyras GA, Van der Geer SB. Letter to the Editor: Microcephaly in ancient Greece, the Minoan microcephalus of Zakros.
    Child's Nervous System 27 (7): 1035. doi: 10.1007/s00381-011-1465-2
    [PDF at Publisher]


  • 2011 Van der Geer AAE, Lyras GA.Field Trip Guidebook. 9th Annual Meeting of the European Association of Vertebrate Palaeontologists. 32 pp.
    [Go to the EAVP site and Download the Field Trip Guidebook]


  • 2011 Van der Geer AAE Wilde Beesten Boek, in Dutch.
    Illustraties door Sudha Devi. Den Haag, Fairbooks.

    Toegankelijk (voor)leesboekje over wilde dieren in India met prachtige illustraties van Sudha Devi en met amusante wetenswaardigheden over de afgebeelde dieren, bijvoorbeeld over de strepen van de Bengaalse tijger, het moederschap van de zeekrokodil en het modderbad van de pantserneushoorn. Fairbooks draagt bij aan eerlijke handel in traditionele kunstuitingen en helpt achtergestelde traditionele kunstenaars zich verder te ontwikkelen. Voor het drukwerk wordt FSC papier gebruikt. Fairbooks boeken zijn verkrijgbaar in de Wereldwinkel. [Meer informatie hier]


  • 2010 Van der Geer A, Lyras G, De Vos J., Dermitzakis M. Evolution of Island Mammals: Adaptation and Extinction of Placental Mammals on Islands.
    Oxford, Wiley-Blackwell (ISBN-13 978-1-4051-9009-1), 479 pp., index, figs, 26 full-colour plates.

    With this richly illustrated book, the first of its kind, the authors offer a much-needed synthesis of recent advances in the exciting field of the evolution and extinction of fossil insular placental mammals. Extinct insular mammals were as diverse and successful as mainland mammals, represented by a wide range of species of dwarf elephants, dwarf hippos, dwarf deer and other 'mini-macromammals' and giant rats, giant insectivores, giant pikas and other 'mega-micromammas', plus a variety of truly bizarre forms. In the recent years, a tremendous amount of research has been conducted on this important subject. The Evolution and Extinction of Placental Island Mammals synthesizes this research into a single, comprehensive volume. Here I, in collaboration with George Lyras, John de Vos and Michael Dermitzakis, explore a variety of topics, including the history of island rules, common patterns and trends, ways of dispersal, speciation and extinction events. A team of distinguished international experts reviewed the separate chapters and provided updated insights in their field. A landmark reference, The Evolution and Extinction of Island Mammals belongs in the library of every paleontologist, mammalogist, and evolutionary biologist. [See Insular Mammals] [Order with price reduction]


  • 2010 Van der Geer A. Dierportretten in steen in Zuid-Azie door de eeuwen heen, in Dutch.
    Aziatische Kunst 40 (3): 2-16.

    Afgaand op de overgeleverde beeldhouwwerken uit het hele subcontinent blijkt maar een handvol wilde dieren uitgebeeld te zijn door de eeuwen heen. Deze alom bekende wilde dieren zijn leeuwen, herten, beren, apen, katten, muizen en ratten, schildpadden, hagedissen, krokodillen, ganzen en pauwen. De rest is eenvoudigweg blijkbaar onbekend en/of onbemind en wordt vaak maar op een enkele sculptuur aangetroffen. Afbeeldingen van Indiase bizons, nilgai, steenbokken, wilde geiten en schapen, antilopen en gazelles, tapirs, eekhoorns, jakhalzen, rode honden, hazen, otters, luipaarden, tijgers, neushoorns en vossen zijn buitengewoon zeldzaam, vooral in relatie tot de overweldigende totale hoeveelheid sculpturen in Zuid-Azië. Rivierdolfijnen zijn met moeite te herkennen in een handvol makaras (watermonsters) en zeekoeien zijn al helemaal nergens te vinden.
    Het grootste aandeel van afgebeelde dieren betreft de grote huisdieren en de olifant. Vooral de dieren met een bijzondere status, hetzij in de maatschappij, hetzij in religie, zijn prominent aanwezig in heel Zuid-Azie, met de olifant als absolute topper, gevolgd door zeboestieren. De waterbuffel komt veelvuldig voor vanwege zijn rol als demon die door de godin Durga gedood wordt en zijn connectie met Yama, de god van de dood. De enige uitzondering is de dromedaris, die ondanks zijn grote economisch belang maar mondjesmaat in beeldhouwwerk vereeuwigd is, iets wat geheel verklaard kan worden door zijn beperkte voorkomen: de halfwoestijnen van het noordwesten en sporadisch in 12e-14e-eeuwse Zuid-Indiase hoofdsteden als geimporteerde strijddieren.
    De kleinere en minder in aanzien staande huisdieren zoals honden, katten, geiten, schapen, mangoesten en varkens komen bijna niet voor in steensculpturen. Als dat al het geval is, dan in associatie met een godheid, meestal een mythe duidend, zoals de hond met Shiva, de kat met de zesde moedergodin Shasthi, de ram met de vruchtbaarheidsgod Naigamesha, de god van het vuur Agni en met de schoolgaande Boeddha, de mangoest met de god van de rijkdom Kubera en het varken met Vishnu's derde avatar; honden en katten figureren daarnaast nog in een paar volksverhalen.


  • 2010 Van der Geer AAE, Lyras GA, Rook L. Body size of insular carnivores: evidence from the fossil record.
    Journal of Biogeography 37: 1007-1021.

    Aim: to (1) assess the generality of one aspect of the island rule—the progressive trend towards size decrease in larger species—for fossil carnivores on islands, (2) offer causal explanations for this pattern and deviations thereof, both as far as fossil carnivores are concerned, and (2) estimate the speed of this trend.Results: Dwarfism is observed in two canid species. Moderate body mass decrease is observed in one hyena species. Gigantism is observed in one otter species. Moderate body-mass increase is observed in two otter species, one galictine mustelid and perhaps one canid. Negligible or no body-mass change at all is observed in five otter species, three galictine mustelids and one genet. Size changes in teeth do not to lag behind in comparison to skeletal elements in the dwarfed canids. The evolutionary speed of dwarfism in a canid lineage is low.


  • 2010 Van der Geer AAE, Dermitzakis M. Fossils in pharmacy: from snake eggs to Saints bones; an overview.
    Hellenic Journal of Geosciences 45: 323-331. This article is the paper version with photographs of the article published in the electronic journal Calicut Medical Journal 2008; 6 (1): e8. [PDF]


  • 2009 Hoek Ostende LW, Meijer HJM, van der Geer AAE. A bridge too far, reply to "Processes of island colonization by Oligo-Miocene land mammals in the central Mediterranean: New data from Scontrone (Abruzzo, Central Italy) and Gargano (Apulia, Southern Italy)" by Mazza P.P.A and Rustioni, M. 2008, Palaeogeography, Palaeoclimatology, Palaeoecology 267, 208-215.
    Palaeogeography, Palaeoclimatology, Palaeoecology 279 (1-2): 128-130, doi:10.1016/j.palaeo.2009.02.029.

    The recent attempt of Mazza and Rustioni (2008) to revive land bridges as a means of colonization of oceanic islands is potentially highly interesting. They suggest that land bridges played an important role in the colonization of the Abruzzo-Apulian bioprovince, as shown by the fossil vertebrates from Scontrone and Gargano. Their evidence however falls short, and even though their paper provides new insights in the history of the insular faunas of the Apulia platform, there is no reason to assume that land bridges played any role in the colonization of these islands. The bizarre insular Apulian fauna is better explained by evolution in isolation by mammals that reached the island through sweepstake dispersal. The new age estimate provided by the Scontrone site places the faunas in the Late Miocene rather than in the Pliocene, and thus in the same time frame as other Italian insular fauna sites such as the Baccinello-Cinigiano fauna of Tuscany and the Fiume Santo fauna of Sardinia (Rook et al., 2006; Abbazzi et al., 2008). [Science Direct]


  • 2009 Van der Geer AAE, De Vos J, Dermitzakis M, Lyras G. Hoe dieren op eilanden evolueren. Majorca, Ibiza, Kreta, Sardinie, Sicilie, Japan, Madagaskar, Malta.
    Utrecht: Veen Magazines, 229pp. ISBN 978 908571 169 8 / NUR 949.

    Op afgelegen eilanden ontwikkelen dieren zich anders. Soms worden ze groter, soms kleiner dan soortgelijke dieren op het vaste land. Dat heeft alles te maken met de uitzonderlijke condities op de eilanden. Dieren die zich het best weten aan te passen aan een dergelijke omgeving, overleven. De aanpassing leidt vaak tot nieuwe varianten. Zo kennen we de miniolifanten, minineushoorn, de kleine vos en de kleine mens op Flores. Dit boek laat zien hoe nieuwe varianten of zelfs nieuwe soorten op de eilanden ontstaan. Ontdek de verdwenen wereld van de reuzenratten, vijfhoornige herten en miniatuurolifanten en lees de spannende verhalen over hun ontdekkingen!
    [See folio (in Dutch), pages 18 and 19] [On-line bestellen bij Bruna (NL)] [On-line bestellen bij Azur (BE)] [Related PowerPoint Presentation (in Italian; Why Paul Sondaar went to Sardinia)]


  • 2009 Van der Geer. Digging into the past.
    In: MI Papagrigorakis, K Dermitzaki, T. Doxanaki, D. Staboliadi (eds.) Geological and Palaeontological Heritage: Retrieval, Conservation, Management and Display. Summer School Professional Development Program, Postgraduate Course of Museum Studies pp.43-48. [PDF download: 201 KB] [Related PowerPoint Presentation (How To Excavate)]


  • 2008 Van der Geer AAE, Dermitzakis DM. Dental eruption sequence in the Pliocene Papionini Paradolichopithecus arvernensis (Mammalia: Primates) from Greece.
    Journal of Vertebrate Paleontology 28 (4): 1238-1244.

    The chronology of tooth emergence can be used to infer life history patterns for extinct species. Comparative studies of extinct primates are hindered by a lack of data on dental development for most species. Here we describe a mandible of the Pliocene papionin Paradolichopithecus arvernensis at an incomplete stage of dental eruption and compare it with published sequences as for living cercopithecoids. The order of tooth eruption is similar to those observed for living papionins. Occlusal ward rotation of developing molars occurs only in the m3, as in other papionins. Age at the time of death is estimated at between 5.0 and 5.3 years. The studied individual died during puberty, which is a stressful period for papionin males. The high percentage of Paradolichopithecus juveniles which died at this stage can be either explained as taphonomic bias or as due to a high rate of mortality during puberty. [BioOne full text]


  • 2008 Van der Geer AAE. Animals in Stone. Indian mammals sculptured through time. Handbook of Oriental Studies, Section 2 South Asia (ed. J. Bronkhorst).
    Leiden: Brill. lxxii, 814 pp, c. 700 ill, index. Hardback. ISBN 978 90 04 16819 0, ISSN 0169-9377, e-ISBN: 9789047443568.

    This magnificently illustrated study of a vast amount of South Asian animal stone sculptures provides an art history covering almost four and a half thousand years, analyzing the art historical, archeological and cultural context of animals in society. [See Animals in Art] [Go to publisher and ordering] [Go to e-Book] [Download Plates (PDF)] [Read the Introduction (PDF c. 7 Mb)]


  • 2008 Lyras GA, Dermitzakis DM, Van Der Geer AAE, Van der Geer SB, De Vos J.The origin of Homo floresiensis and its relation to evolutionary processes under isolation.
    Anthropological Science 117, 33-43.

    Since its publication in 2004, Homo floresiensis has been attributed to a species ofn its own, a descendant of H. erectus or another early hominid, a pathological form of H. sapiens, or a dwarfed modern human related to the Neolithic inhabitants of Flores. In this contribution, we apply a geometric morphometric analysis to the skull of H. floresiensis (LB1) and compare it with skulls of normal H. sapiens, insular H. sapiens (Minatogawa Man and Neolithic skulls from Flores), pathological H. sapiens (microcephalics), Asian H. erectus (Sangiran 17), H. habilis (KNM ER 1813) and Australopithecus africanus (STS?Sts 5). Our analysis includes specimens that were brought to the fore by other authors to prove their conclusions. The geometric morphometric analysis separates H. floresiensis from all H. sapiens, including the pathological and the insular forms. It is not possible to separate H. floresiensis from H. erectus. Australopithecus falls apart from all other skulls. The Neolithic skulls from Flores fall within the range of modern humans and are not related to LB1. The microcephalic skulls fall within the range of modern humans, as well as the skulls of the Neolithic small people of Flores. The cranial shape of H. floresiensis is close to that of H. erectus and not to that of any H. sapiens. Apart from cranial shape, some features of H. floresiensis are not unique but shared with other insular taxa, such as the relatively large teeth (shared with Neolithic humans of Sardinia), and changed limb proportions (shared with Minatogawa Man). [PDF] [Go to publisher]


  • 2008 Van Der Geer AAE. The effect of insularity on the Eastern Mediterranean early cervoid Hoplitomeryx: the study of the forelimb.
    Quaternary International 182, 1: 145-159. doi:10.1016/j.quaint.2007.09.021.

    On the Tertiary paleo-island Gargano a highly endemic, unbalanced vertebrate fauna evolved including the five-horned deer Hoplitomeryx. Its post-cranial material contains four size groups.The question whether the morphotypes are chronomorphs or ecomorphs is addressed. Sexual dimorphism is ruled out as the underlying principle of size separation in this case, based upon body mass estimations and data from living deer. Chronomorphs is the best explanation for the Megaloceros cazioti lineage (Pleistocene, Sardinia) and the Myotragus balearicus lineage (Pliocene–Holocene, Mallorca). Ecomorphs are a better explanation for the size groups of Candiacervus (Pleistocene, Crete) and Cervus astylodon (Pleistocene, Ryukyu Islands). An adaptive radiation into several trophic types took place, promoted by the ecological meltdown of the ancestral niche. The drive behind this speciation is increased interspecific competition. For Hoplitomeryx, although the hypothesis of chronomorphs cannot be discarded, that of ecomorphs seems most likely, based upon the coexistence of two or more size groups per fissure, and upon the presence of a huge morphotype, larger than mainland species, in the younger fissures. [PDF download] [Science Direct full text and pdf]


  • 2008 Van der Geer AAE, Dermitzakis MD. Fossil medicines from snake eggs to Saint s bones; an overview
    Special article. Calicut Medical Journal 2008; 6 (1): e8.

    During the centuries, fossil remains of invertebrate and vertebrate animals have been widely used as medicines to cure a disease or relieve a symptom, or as amulet to prevent a disease or symptom. The most common medicinal fossils are the invertebrate remains (sea urchins, ammonites, belemnites, trilobites), followed by shark teeth and palatal teeth of bony fishes. More rare, but surviving on a large scale till the present day, is the use of fossil mammals, known as “dragons”. Knowledge of the use of fossil medicines broadens the view of especially medical practitioners in remote or tribal regions. These people hold strong beliefs in the working principles of the fossils and this should not be dismissed too easily. The working area of fossil medicines have a wide range including poisoning, sore throats, internal pains and cramps, infertility and obstetrical problems, bladder and kidney diseases, eye infections and diftheria. [PDF] [Related PowerPoint Presentation "Fossils as Medicines in Past and Present"]


  • 2008 Van der Geer AAE, Dermitzakis MD, De Vos J. Fossil Folklore from India: The Siwalik Hills and the Mahabharata.
    Folkore 119: 71-92. London: The Folklore Society.

    The Siwalik Hills, below the Himalayas, are strewn with impressive Plio-Pleistocene vertebrate fossils. We suggest that the region was seen as the historical stage for the legendary battle as described in the Indian epic Mahabharata, during which hundreds of mighty and sometimes gigantic heroes, horses, and war elephants died. Their remains are seen in the fossil bones, skulls, jaws and tusks of hippopotamuses (Hexaprotodon), proboscideans (Stegodon, Archidiskodon), four-horned giraffes (Sivatherium, Giraffokeryx), giant tortoises (Geochelone), sabre-toothed tigers (Paramachairodus), camels (Camelus), and other species. Moreover, thousands of ancient bronze javelins and spears are found on the surface in the same region. These archaeological artifacts along with the paleontological remains appear to have influenced the setting and context of the great battle in the Indian epic. [Abstract][Go to Publisher] [PDF via Informaworld] [PDF] [Related PowerPoint Presentation]


  • 2007 Dermitzakis M., Iliopoulos G., Van Der Geer A, Lyras G.A. The Rise and Fall of the Cretan Deer. XVII INQUA Congress, July 28 – August 3 2007, Cairns, Australia. Quaternary International. [PDF] doi:10.1016/j.quatint.2007.03.000


  • 2007 Lyras GA, Van Der Geer AAE. The Late Pliocene vertebrate fauna of Vatera (Lesvos Island, Greece). Cranium 24 (2): 11-24. [PDF]


  • 2007 De vos J, Van Der Geer AAE. Fossiele faunas van de eilanden van de Middellandse Zee.
    GEA 2007 (3): 87-90.

    De Galapagos eilanden hebben bij Charles Darwin een belangrijke rol gespeeld omtrent het denken over evolutie. Hier ontdekte hij dat, hoewel de dieren op deze eilanden overeenkomsten vertonen met die van Patagonie (de zuidelijke punt van Zuid-Amerika), ze toch verschillend zijn. Ten tweede realiseerde hij zich dat de soorten van eiland tot eiland verschillen, ook al liggen de eilanden minder dan 100 km van elkaar. Op deze gedachte was hij gebracht door mr Lawson, een Engelsman die gouverneur was van de Galapagos eilanden. Deze vertelde DArwin dat hij onmiddellijk kon zien van welk eiland een bepaalde schildpad kwam. Elk eiland heeft blijkbaar zijn eigen evolutionaire geschiedenis. Van recente eilanden is bekend dat ze vreemde faunas kunnen hebben, denk aan de Darwinvinken van de Galapagos eilanden, maar dat dit ook opgaat voor fossiele faunas is minder bekend. Dit artikel laat zien wat voor vreemde faunas er in het verleden op de eilanden van de Middellandse Zee hebben geleefd.


  • 2006 Van Der Geer AAE, Dermitzakis M, De Vos J. Crete before the Cretans: the reign of dwarfs.
    Pharos 13: 121-132. Athens: Netherlands Institute.

    When archaeologists speak of prehistory, they have epochs in mind as bronze age, stone age: epochs that are revealed to us by means of artefacts, left overs of a human culture from a time before the emergence of written or pictographical sources. However, there is far more prehistory than history, and major part lies well before the archaeological prehistory. This is the domain of the palaeontology, where geological epochs are revealed by means of fossils in the broad sense. The island of Crete as we know, yielded a vast amount of cultural remains, among which those of the Minoan culture became world famous. But Crete also appeared to be a treasure box of much older remains, and 63 localities with fossils have been reported. From the 1970’s on, Dutch researchers (University of Utrecht) started excavations on Crete, in close collaboration with the University of Athens. Based upon the hitherto described fossils, the pre-prehistory of Crete and its early inhabitants can be reconstructed. In this article, we focus on that part of the Cretan history between the time of its emergence as we know it and the first arrival of humans on the island. [PDF] [Go to Pharos 13] [Go to the Netherlands Institute at Athens (Palaeontology)]


  • 2006 Van der Geer AAE, De Vos J, Lyras G, Dermitzakis M. New data on the Pleistocene Cretan deer Candiacervus sp. II (Mammalia, Cervinae).
    In: Kahlke R-D, Maul LC, Mazza P (eds). Late Neogene and Quaternary biodiversity and evolution: Regional developments and interregional correlations. Proceedings of the 18th International Senckenberg Conference (VI International Palaeontological Colloquium in Weimar) vol. I. Courier Forschungsinstitut Senckenberg 256: 131-137.

    A composite skeleton of Candiacervus species II revealed new features that were not detected in the isolated elements. The species differs from all known recent and extinct mainland deer, mainly in its body proportions and considerably shortened distal limb elements. The species had a more or less normal vertebral column length relative to continental large deer, and moderately upwards curved lumbar section, both features reminding us more of the insular dwarf bovid Myotragus than of mainland small deer like Axis axis. Combined with an increased massivity of all bones and pronounced muscle scars, this change in body proportions appears to indicate that the species evolved towards the niche of goat-like bovids in rocky environments. Other additional diagnostic features are the horizontally directed transversal processus of the vertebras, fusion of the lateral metacarpal to the main metacarpal, a tail length of ten vertebras, a more pronounced difference between anterior and posterior hooves, and the presence of lateral toes upto the third phalanx, anterior as well as posterior. [go to CFS] [request a PDF: 2.964 ]


  • 2006 Lyras GA, Van Der Geer AAE. Adaptations of the Pleistocene island canid Cynotherium sardous (Sardinia, Italy) for hunting small prey.
    Cranium 23 (1): 51-60.
    [go to Cranium] [Abstract] [PDF download: 681 KB]


  • 2006 Lyras GA, Van Der Geer AAE, Dermitzakis MD, De Vos J. 2006. Cynotherium sardous, an insular canid (Mammalia: Carnivora) from the Pleistocene of Sardinia, and its origin.
    Journal of Vertebrate Paleontology 26(3): 735-745.

    The phylogenetic position of Cynotherium sardous remained unsolved for more than five decades, mainly because inherited ancestral characters and acquired adaptations to different ecological pressures could not be separated. In this study the problem is approached again, with the use of morphological features that were either overlooked or could not be explained properly, in combination with results from recent major revisions of canid phylogeny. Xenocyon is the most parsimonious ancestor of Cynotherium. This large hypercarnivorous canid, once on the island, faced a rather different menu consisting of small and swift prey only. The subsequent necessary adaptation resulted in a small-sized dog which carried its head much in the way foxes do and was able to hold its body low to the ground and move its head laterally better than any living canid. Its dentition and brain morphology remained much the same, whereas its skull lost the typical fortifications seen in the other hypercarnivorous canids. [view to publisher] [Abstract] [request a PDF: 1.631 KB] doi:10.1671/0272-463(2006)26[735:CSAICM]2.0.CO;2


  • 2006 Dermitzakis MD, Van Der Geer AAE, Lyras GA. 2006. Paleopathological observations on a population of fossil deer from the Late Pleistocene of Crete.
    In: A Kalofourtis, N Papadopoulos, C Spiliopoulou, K Maravelias, A Chatziioannou (eds) Volume in honuor of Professor Andonis Koutselinis. pp.43-51. Athens. [IN GREEK] [Abstract] [PDF download: 2.376 KB]


  • 2006 Van der Geer A, Dermitzakis M, De Vos J. Fossils and myths in North India: is there a connection between the Siwalik Hills and the Mahabharata?.
    The 19th European Conference of Modern South Asian Studies, 27-30 June 2006, Leiden the Netherlands. Abstracts: p 124. Leiden: IIAS.

    All over the world, people have explained fossil findings as the proof for the historical value of legends, stories, myths, or used them as a basis for a new legend. North India does not differ in this respect. In Nepal and northernmost India, fossil ammonites (shalagramas) are worshipped as cakras, be it the disc of Vishnu or the Buddhist wheel, or seen as links to the divine snake Kundalini. Offered to the mountain gods, they yield protection. Fossil sea urchins were found in neolithical graves in the Salt Range of Pakistan; most likely they had some magical function, as elsewhere in the world. In Kashmir, Jurassic fossil brachiopods were copied in wood and painted. They probably were worshipped as the sacred tortoises known in Buddhism. In this contribution, we investigate the possibility of a link between the famous fossil bone beds of the Siwaliks and the plain of Kurukshetra, the historical stage for the legendary battle as described in the epic Mahabharata, during which hundreds of mighty and sometimes gigantic heroes, horses and elephants died. Their remains, added with those of their huge, wrecked chariots, and thousands of javelins and spears, may very well be seen in the fossil bones, skulls, jaws and tusks of long extinct hippopotamuses (Hexaprotodon), proboscideans (Stegodon, Archidiskodon), giant giraffs (Sivatherium, Giraffokeryx), giant tortoises (Geochelone), sabre-toothed tigers (Paramachairodus), camels (Camelus), and so on. [Abstract]


  • 2006 Dermitzakis M, Roussiakis S., Van der Geer AAE. Sto Mouseio - Mosasaurus. In Greek and English.
    National and Kapodistrian University of Athens, Museum of Palaeontology and Geology, Athens; 55 pp. Educational material (not for sale) for students. Partly based on information and plates from The Oceans of Kansas by Michael Everhart.

  • 2006 Sondaar PY, Van Der Geer AAE, Dermitzakis M The unique postcranial of the Old World monkey Paradolichopithecus: more similar to Australopithecus than to baboons.
    Hellenic Journal of Geosciences 41, 1: 19-28. Special volume in the memory of Paul Yves Sondaar.

    This article deals with the unique postcranial of Paradolichopithecus arvernensis and its possible way of locomotion insofar this can be inferred from the present material. The postcranial material is described and compared with that of its living close relatives Papio, Macaca, and Theropithecus. As some unique features were found in Paradolichopithecus, the comparison was extended to Australopithecus anamensis, A. afarensis (AL 288-1) and Pan troglodytes. The features that discriminates Australopithecus from the African apes, also set Paradolichopithecus apart from baboons. This parallel was unexpected in the light of the general morphological differences between monkeys and apes. The study of Paradolichopithecus might help us understanding the locomotion of Australopithecus, which differed from that of chimpanzees by an increased frequency of an energetically expensive bipedal mode with bent knees, certainly different from that of Homo as can be inferred from the totally different talar bone architecture. Paradolichopithecus was more terrestrial than baboons and likewise Australopithecus was more terrestrial than chimpanzees (of today), but not in the same way as us. [PDF download: 868 KB]


  • 2006 Van Der Geer AAE, Dermitzakis M. Relative growth of the metapodals in a juvenile island deer: Candiacervus (Mammalia, Cervidae) from the Pleistocene of Crete.
    Hellenic Journal of Geosciences 41, 1: 119-125. Special volume in the memory of Paul Yves Sondaar.

    One of the diagnostic features of Candiacervus are its apparently shortened and more massive metapodals in comparison to its ancestor. The question is whether this shortening and increased massivity are already present at birth or arises during postnatal ontogeny due to differences in relative growth speed. From this study it appears that the shortening is already present at birth but increases further during postnatal ontogeny due to a relative slower growth speed. The same holds for the increased massivity. [PDF download: 746 KB]


  • 2005 Van Der Geer AAE, De Vos J, Lyras GA, Dermitzakis MD. 2005. The mounting of a skeleton of the fossil species Candiacervus sp.II from Liko Cave, Crete, Greece.
    Proceedings of the International Symposium Insular Vertebrate Evolution: The Palaeontological Approach. Monogafies de la Societat d Historia Natural de les Balears 12:337-346.
    [Abstract][PDF download: 423 KB]


  • 2005 Van Der Geer AAE. Island ruminants and the evolution of parallel functional structures. In: Cregut E (ed.): Les ongules holarctiques du Pliocene et du Pleistocene. Actes Colloque International, Avignon, 19-22 septembre. Quaternair 2005 hors-serie 2: 231-240. [PDF download: 886 KB]


  • 2005 Sondaar PY, Van der Geer AAE. Evolution and Extinction of Plio-Pleistocene Island Ungulates.
    In: Cregut E (ed.): Les ongules holarctiques du Pliocene et du Pleistocene. Actes Colloque International, Avignon, 19-22 septembre. Quaternair 2005 hors-serie 2: 241-256.

    The pattern of faunal evolution on islands differs fundamentally from that on the mainland. Major faunal turnovers on the mainland are mainly triggered by global climatological changes but mainly by changes in paleogeography and the new arrival of predators on islands. Three types of Pleistocene islands are studied here: continental islands (Sardinia, Corsica), oceanic-like islands (Crete, Cyprus, Central Ryukyu Islands, Japan) and filter-bridge islands (Late Pleistocene Sicily and Japan). The origin of the founder population of the first type is a mainland fauna, while the second type is colonized by overseas sweepstake dispersal. The third type is characterized by filter dispersal from the continent. The lack of transitional faunas between the founder population and the endemic population shows that the evolutionary scenario in the ungulate fauna on islands of the first and second type is characterised by rapid major evolutionary changes in the founder poulation, explained as adaptation to the island environment, followed by a relatively static period, which in some cases ends abruptly with a dramatic faunal turnover. The duration of this equilibrium differs from island to island, but as a rule comes to an end after new arrivals. Again there is no transitional fauna between the original endemic fauna and the newer endemic fauna. Neolithization of islands causes extinction of the endemic impoverished island fauna, which is replaced by domestic live stock they brought in. The third type of island is less predictable in its faunal content, as the effect of a filter bridge is highly dependent on the nature of the filter. In the case of Sicily, the ungulate fauna is characterized by a gradually replacement, where the smaller endemics of the previous period coexist with the newly arrived mainland taxa. [PDF download: 225 KB]


  • 2005 Van Der Geer AAE. The postcranial of the deer Hoplitomeryx (Mio-Pliocene; Italy): another example of adaptive radiation on Eastern Mediterranean Islands.
    Monografies de la Societat d'Historia Natural de les Balears 12: 325-336. [PDF download: 384 KB]


  • 2004 Dermitzakis MD, Van Der Geer AAE, Lyras GA. 2004. The phylogenetic position of raccoon dogs: implications of their neuroanatomy.
    Proccedings of the 5th International Symposium on Eastern Mediterranean Geology, 14 to 20 April, 2004, Thessaloniki, Greece, p. 307-310. [PDF download: 312 KB]


  • 2003 Lyras GA, Van Der Geer AAE. 2003. External brain anatomy in relation to phylogeny of Caninae (Carnivora: Canidae).
    Zoological Journal of the Linnean Society 138:505-522.doi:10.1046/j.1096-3642.2003.00067.x

    Caninae is one of the most studied mammalian groups, nevertheless there are relatively few comparative studies on their neuroanatomy. This work contributes to a better knowledge of this subfamily since it describes the external cerebrum anatomy of 29 out of the 35 living Caninae species, 11 of which are described for the first time. Information about their frontal region appears to be a welcome supplement in the study of the phylogeny. Two distinctive features are recognized, that can be traced back in the fossil record: the sulcal pattern medial to the coronal sulci, and the shape and relative size of the proreal gyrus. Four types are described for the first feature, (1) orthogonal: Canis, Lycaon, Cuon, Atelocynus, Speothos, (2) pentagonal: Vulpes, Alopex, Otocyon, Eucyon (extinct), (3) parenthesis-like: Dusicyon (extinct), Pseudalopex, Chrysocyon, (4) heart-shaped: Urocyon, Cerdocyon, Pseudalopex culpaeus, Nyctereutes. Three types are described for the second feature, (1) elongated and bilaterally compressed: Canis, Cuon, Lycaon, Atelocynus, Speothos, Cerdocyon, Dusicyon (extinct), Chrysocyon, Pseudalopex, Nyctereutes sinensis (extinct), N. tingi (extinct), (2) small: Vulpes, Otocyon, Urocyon, Alopex, (3) wide and low: Nyctereutes procyonoides. On the basis of these features some phylogenetic interpretations are presented: the fossil Asian Nyctereutes is close to Cerdocyon, Speothos is close to Atelocynus, Chrysocyon is not related to Canis, Urocyon differs from Vulpes and Pseudalopex culpaeus differs from the rest of the Pseudalopex species. [view to publisher] [Abstract] [request a PDF: 756 KB]


  • 2002 De Vos J, Van Der Geer AAE. Major patterns and processes in biodiversity: taxonomic diversity on islands explained in terms of sympatric speciation.
    In: Waldren & Ensenyat (eds). World Islands in Prehistory, International Insular Investigations, V Deia International Conference of Prehistory. Bar International Series 1095: 395-405.

    Pandemic biodiversity is due to evolutionary processes in which every species evolves from another species through natural selection in a broad sense. Selection is mainly initiated and directed by availability and character of ecological niches. Radiation within a taxon takes place as soon as a new, free ecological niche is entered successfully, in other words, after an innovation of this taxon or after a mass extinction of other, competitive taxa. For example, the development of jaws (innovation), and later fins, in the agnatha was followed by a large-scale, long-term radiation into numerous groups of fishes during the Devonian. A similar pattern is seen in amphibians in the Carbonian (innovation: land dwelling), the amniota in the Trias (innovation: egg with membranes), sauriers in the Mesozoic (survivors of mass extinction), and mammals in the Kenozoic (survivors of mass extinction; innovation: versatile dentition). The same is seen in lower phylogenetic levels, resulting in medium-scale, medium-term radiations, e.g. ungulates (innovation: stilt-like limbs to run the plains), mainly in the Miocene. Each newly evolved taxon displays a minor change from the innovative ancestor, and as a specialist occupies a part of the total newly entered niche. Thus, after each innovation, sympatric speciation events take place, later followed by dispersals and allopatric speciation events. The speciation leads to homochronuous specialists, each adapted to a subniche of the main niche that was originally occupied by the innovative pioneer or colonizer.
    This explains the small-scale, short term radiation seen in endemic insular taxa. On islands, biodiversity within one taxon is the rule, and the most parsimonious explanation is to consider this diversity, too, as determined by availability and character of ecological niches, as on the mainland. The colonizers have no competitors, so have the unique possibility to radiate beyond the degree seen on the mainland, where close niches are always already occupied. Island species, depending on plasticity of functional structures, will enter all possible niches, and adapt to all available niches. Clear examples are the large continental islands: the carnivorous marsupials and herbivorous mammals of South America during the Tertiair, and the marsupials of Australia during the Kaenozoic were able to radiate into a huge variety of taxa after colonization. The biodiversity as seen in endemic insular monophyletic genera in the form of adaptive radiation is in complete accordance with the major patterns and processes that gave rise to the long-term, large-scale and the medium-term, medium-scale biodiversity on the mainland. [PDF download: 110 KB]


  • 2002 Sondaar PY, Van Der Geer AAE. Plio-Pleistocene terrestrial vertebrate faunal evolution on Mediterranean islands, compared to that of the Palearctic mainland.
    Proc. of the 1st Int. Workshop "On Late Plio/Pleistocene extinction and evolution in the Palearctic. The Vatera site." Annales Geologiques des Pays Helleniques 1e Serie 39, A: 165-180. [PDF download: 134 KB]


  • 2002 Sondaar PY, Van der Geer AAE. Arboreal and terrestrial traits as revealed by the primate ankle joint..
    Proc. of the 1st International Workshop "On Late Plio/Pleistocene extinction and evolution in the Palearctic. The Vatera site." Annales Geologiques des Pays Helleniques 1e Serie 39, A: 87-98.

    The tarsal bones are important in the study of primate locomotion and posture, as it is here that the body weight is transferred to the ground in standing, walking and running, each with its particular demands. Though there are systematic differences in general morphology between cercopithecoids and African hominoids, for example the shape of the talar trochlea and the groove for the large toe flexor, there are clear parallels in function. In the proximal talar joint, movement is restricted to dorsal and plantar flexion, whereas in the distal talar joint also rotation and medio-lateral movement are possible. Especially the distal talar joint is useful to discriminate between arboreal and terrestrial ways of life, for example, rotation is typical for arboreal primates. The proximal talar joint is useful to specify the type of terrestrial locomotion. The degree of possible flexion differs between species, furthermore, in a number of species there is no medial rotation during maximal plantar flexion at all, whereas in most species at least a minimal degree occurs. In the species without medial rotation, such as Paradolichopithecus, the ridges of the trochlea tali tend to run more parallel than in other terrestrial species, like Papio, resulting in minimal trochlear wedging.
    A functional analysis of the newly discovered ankle joint of Paradolichopithecus arvernensis leads to the conclusion that this monkey had not only a terrestrial way of life, but has also a gait similar to that of Australopithecus afarensis, revealing thus a parallel evolution between cercopithecoids and hominoids in this respect. This puts question marks to the degree and type of bipedalism in Australopithecus [PDF download: 311 KB]


  • 2002 Van der Geer AAE, Sondaar PY. The postcranial elements of Paradolichopithecus arvernensis (Primates, Cercopithecidae, Papionini) from Lesvos, Greece..
    Proc. of the 1st International Workshop "On Late Plio/Pleistocene extinction and evolution in the Palearctic. The Vatera site." Annales Geologiques des Pays Helleniques 1e Serie 39, A: 71-86.

    The morphological features that are unique for Paradolichopithecus amongst the monkeys are described for the talus, distal tibia and the humerus, and are as follows. The talus is discriminated by its almost parallel trochlea, the large flap-like, protruding fibular suspensory facet, and a slightly deeper facet for the spring ligament on the talar head. These features are suggestive for a baboon-like ankle joint with the body weight more evenly distributed over the talar trochlea, a greater proportion of the weight transfer through the lateral (fibular) side, and with approximate the same stability in maximal dorsiflexion as in maximal plantar flexion. The distal tibia is discriminated by a more massive, square and blunt malleolus that lacks the typically pronounced ball-shaped area, a wider groove (sulcus malleolaris) for the tendon of the M. tibialis posterior, a more square cross-section, clear scars for the fibula, and a double tendon groove on the dorsal surface (either for a bifurcated tendon for the M. flexorum tibialis posterior or a pronounced groove for the long toe flexor), which follows the parasagittal plane. The combination indicates a maintainance of the close-packed situation from dorsiflexion to plantar flexion, an increased importance of the fibula in weight transfer, a stronger plantar flexion, and possibly a slightly abducted foot. The humerus is discriminated by an increased articulation area on the head compared to Papio, a wide and deep groove for the biceps tendon, a gradually descending capitulum, and an oblique axis for flexion-extension through the elbow joint. During flexion, the ulna deviates from the parasagittal plane, and ends in a position medially to the humerus instead of parallel above it, due to the trochlear shape and axis. This unique feature yields a significant increased mobility.
    [PDF download: 670 KB]


  • 2001 Lyras GA, Van Der Geer AAE, Dermitzakis MD. 2001. Evolution of the brain of Plio-Pleistocene wolves.
    Cranium 18(2):30-40. [go to Cranium] [Abstract]


  • 2001 Van der Geer B, Van der Geer AAE. Dagboek van een opgraving: Corbeddu, zaal IV. Cranium 18, 2: 3-14. In Dutch with English summary.


  • 2000 Sondaar PY, Van der Geer S Mesolithic environment and animal exploitation on Cyprus and Sardinia/Corsica. In: Mashkour, M., A. Choyke & M. Buitenhuis (eds). Proceedings of the IVth ASWA Symposium, IVA: 67-73. Paris. [PDF download: 116 KB]


  • 1999 Van der Geer AAE On the astragalus of the Miocene endemic deer Hoplitomeryx from the Gargano (Italy). Deinsea 7: 325-336. Rotterdam: Natuurmuseum. This report compares the astragalus of the insular deer Hoplitomeryx with that of a number of recent and fossil ruminants. It appears that the profile of the dorsal border deviates from the expected situation. In addition, in many astragali the axis through the cranial and the caudal half meet each other at an angle, yielding an oblique appearance. This situation resembles that of Myotragus balearicus, another endemic ruminant from the Mediterranean. A probable explanation is the decrease of muscular power needed, and the increase of stability, in relation to the convergence of the upper legs, due to a larger abdomen. Hoplitomeryx certainly was neither a runner nor a jumper. [PDF download: 696 KB]


  • 1998 Van Der Geer AAE. The Bhasa Problem. A statistical research into its solution. PhD Thesis. Rijksuniversiteit Leiden; 243 pp. [go to my PhD]


  • 1998 Van der Geer AAE. De reuzen, dwergen en rariteiten van de Gargano and Over hoorns gesproken. Cranium 15, 2: 75-83 and 111-123. Both in Dutch with English summary.


  • 1996 Van Der Geer AAE. Samskrtabhasa B1, cursus Sanskrit voor beginners and Samskrtabhasa B2, cursus Sanskrit voor gevorderden. Leiden: Talen Instituut Console; 366 and 233 pp resp. Both in Dutch. [go to my Sanskrit course (in Dutch)]


  • 1996 Van Der Geer AAE. Sardinie and Saksen. Klein Duimpje Reisgidsen. Leiden: Uitgeverij Console. Both in Dutch. [go to my travel guides Sardinia and Saxonia (in Dutch)]


  • 1995 Van Der Geer AAE. Isco sa limba mea. Sardijns in 10 lessen and Woordenboek Nederlands-Sardijns. Ditzionariu Sardu-Olandesu and Ittesisiat, Sardijns voor op vakantie. Leiden: Talen Instituut Console; 229 pp, 240 pp and 15 pp. All three in Dutch and Sardinian. [go to my Sardinian language course (in Dutch)]


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