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.
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may not be reproduced. The files reflect the holdings of the various
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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 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.
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)]
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)]
