VARIATION OF U-MICRODISTRIBUTION IN FOSSIL HIPPARION TEETH AS A COMPLICATING FACTOR IN DATING STUDIES

Five Upper Miocene fossil Hipparion molars were studied for U-distribution by Fission Track. U-uptake has reached the whoie mass of the teeth and no saturation fronts seem to occiir in the interior layers. Mean U-concentration in dentine, cement and enamel was 157, 139 and 78 ppm, respectively. Uenamel/Uderltinr -0.5 is considerably higher than 0.1 reported in the past for Upper-Quaternary mammoth teeth. These features are disadvantageous for ESR-dafing in Hipparion enamel, although a long-lived signal (g=2.0018) is apparent. Leaching phenomena occur in the outer regions of these teeth. Inner enamel folding seems to have hindered a more uniform U-distribution in the teeth

Convergence and divergence in the evolution of cat skulls: temporal and spatial patterns of morphological diversity

Background: Studies of biological shape evolution are greatly enhanced when framed in a phylogenetic perspective. Inclusion of fossils amplifies the scope of macroevolutionary research, offers a deep-time perspective on tempo and mode of radiations, and elucidates life-trait changes. We explore the evolution of skull shape in felids (cats) through morphometric analyses of linear variables, phylogenetic comparative methods, and a new cladistic study of saber-toothed cats. Methodology/Principal Findings: A new phylogenetic analysis supports the monophyly of saber-toothed cats (Machairodontinae) exclusive of Felinae and some basal felids, but does not support the monophyly of various sabertoothed tribes and genera. We quantified skull shape variation in 34 extant and 18 extinct species using size-adjusted linear variables. These distinguish taxonomic group membership with high accuracy. Patterns of morphospace occupation are consistent with previous analyses, for example, in showing a size gradient along the primary axis of shape variation and a separation between large and small-medium cats. By combining the new phylogeny with a molecular tree of extant Felinae, we built a chronophylomorphospace (a phylogeny superimposed onto a two-dimensional morphospace through time). The evolutionary history of cats was characterized by two major episodes of morphological divergence, one marking the separation between saber-toothed and modern cats, the other marking the split between large and small-medium cats. Conclusions/Significance: Ancestors of large cats in the ‘Panthera’ lineage tend to occupy, at a much later stage, morphospace regions previously occupied by saber-toothed cats. The latter radiated out into new morphospace regions peripheral to those of extant large cats. The separation between large and small-medium cats was marked by considerable morphologically divergent trajectories early in feline evolution. A chronophylomorphospace has wider applications in reconstructing temporal transitions across two-dimensional trait spaces, can be used in ecophenotypical and functional diversity studies, and may reveal novel patterns of morphospace occupation

First occurrence of carnivore footprint with hyaenid affinities from the Late Miocene of Crete (Greece)

Nine terrestrial mammal localities of Miocene age based on body fossils have been reported from the island of Crete to date. A new locality where footprints of terrestrial mammals were exposed has recently been discovered in western Crete. Platýlakkos, the locality, is situated near the village Voúves, west of the city of Chaniá. The ichnofossils come from lacustrine deposits that belong to the Chátzi Formation. The most impressive finding is a clearly defined footprint that might be referred to a large-sized hyaenid. The footprint impression, a convex hyporelief on a sandstone slab, is a natural cast of a left manus where the traces of the interdigital pad and all four digital pads, as well as their respective claw marks-are clearly visible. Based on nearby marine deposits of the Chátzi Formation, the age of the fossiliferous layer with the footprints can be considered to be early to middle Turolian (MN11-MN12) in terms of mammalian biochronology. To date, there is no certain record of Miocene large-sized hyaenid footprints worldwide, and thus this isolated footprint might belong to a new ichnotaxon. However, in the absence of a trackway, the erection of a new ichnotaxon is avoided. The Platýlakkos findings are the first recorded case of fossil land mammal footprints from the Neogene of Crete, and Greece in general. They further the evidence for the presence of well-established terrestrial environments and faunas in the area of Crete during the Late Miocene. © Senckenberg Gesellschaft für Naturforschung and Springer 2012

Population dynamics on Aetokremnos hippos of Cyprus or have Cypriots ever tasted hippo meat?

The use of life tables in age-graded mandibles of the endemic pygmy hippopotamus Hippopotamus minor from Aetokremnos Cyprus suggests that death occurred by natural causes such as accidents, genetic abnormalities and endemic diseases rather than catastrophic causes. Comparison of H. minor and modern Hippopotamus amphibius life tables suggests the birth of one offspring per female per year and the occurrence of mating and birth seasons. Hunting by prehistoric humans whose tools were found in proximity with the hippopotamus bones is not justified by the life tables that have been produced. The use of the wet rockshelter of Aetokremnos as a living area during the day, in the same way that extant H. amphibius use lake water, is instead proposed as a probable explanation for the extensive accumulation of bones. © 2020 Elsevier Ltd and INQU

Frontal bone pneumatisation in Tragoportax and Miotragocerus (Mammalia, Bovidae) from the Late Miocene of Greece

Bovidae display a distinctive cranial architecture, characterised by multifarious frontal sinuses varying in size and shape. These features are usually considered to be of phylogenetic importance and their functional importance still remains elusive. Pneumatisation is the process in which cranial sinuses result from the resorption and deposition of the bone in response to biomechanical stress. In this study, we use high resolution computed tomography (CT-scanning) to identify these internal cranial structures on 12 bovid cranial specimens from Upper Miocene Greek localities. The present study focuses on two genera, Tragoportax and Miotragocerus, so as to explore the variance inside this group in terms of frontal sinuses. The non-destructive nature of this method allows 3D digital representation of cranial internal features of fossilised material in high resolution, providing also volumetric data of the sinuses. We demonstrate the unique internal morphology that these species possess. This morphology is comprised by wide frontal sinuses conforming closely to the shape of the frontal bone and that extend up to the base of their horn cores. The volume of the sinuses was strongly correlated to the frontal bone size and cranial volume. © 2021 Informa UK Limited, trading as Taylor & Francis Group

A new Late Miocene ovibovine-like bovid (Bovidae, Mammalia) from the Kassandra Peninsula (Chalkidiki, Northern Greece) and implications to the phylogeography of the group

A new Late Miocene bovid, Urmiatherium kassandriensis sp. nov., from Northern Greece is described. The material comes from the Fourka locality in the Kassandra Peninsula (Chalkidiki), and the included fauna is estimated to be of Vallesian age. The two preserved crania represent a medium-sized taxon with short, conical horn cores, a flat cranial roof (consisting of the posterior part of the frontals, parietal and occipital), thick and porous frontals and pneumatized short parietals, an extremely thick basioccipital with voluminous posterior tuberosities and accessory articular facets for the atlas. The specialized atlanto-occipital joint recalls Pleistocene and extant ovibovines, but the braincase structure as a whole and the horn core features closely match Late Miocene ovibovine-like taxa, especially Plesiaddax and even more Urmiatherium. Nevertheless, the Kassandra bovid differs from representatives of both genera in the simpler horn core morphology and external brain anatomy. Urmiatherium is known to appear first in China and Iran at about 7.8 Ma, whereas its westernmost appearance on Samos Island (Greece) is dated much later. The presence of Urmiatherium kassandriensis sp. nov. in N. Greece suggests a farther west and earlier (Vallesian at least) first appearance of the genus. This would justify a basic geographic and phylogenetic split of Urmiatherium into two main Turolian lineages: a central-eastern Asian one leading to the sister species U. polaki and U. intermedium and a western one leading to U. rugosifrons. © 2017, Paläontologische Gesellschaft

Variation of U-microdistribution in fossil Hipparion teeth as a complicating factor in dating studies

Five Upper Miocene fossil Hipparion molars were studied for U-distribution by Fission Track. U uptake has reached the whole mass of the teeth and no saturation fronts seem to occur in the interior layers. Mean U-concentration in dentine, cement and enamel was 157, 139 and 78 ppm, respectively. Uenamel/Udentine ≈ 0.5 is considerably higher than 0.1 reported in the past for Upper-Quaternary mammoth teeth. These features are disadvantageous for ESR-dating in Hipparion enamel, although a long-lived signal (g=2.0018) is apparent. Leaching phenomena occur in the outer regions of these teeth. Inner enamel folding seems to have hindered a more uniform U-distribution in the teeth. © 1992 Akadémiai Kiadó

Morphological analysis of Cricetodon aliveriensis (Rodentia, Mammalia) from the locality of Karydia (Rhodope, Northern Greece)

Cricetodon is present in the early Miocene of Greece in six assemblages, Cricetodon aliveriensis Klein Hofmeijer and de Bruijn, 1988 in Aliveri and Karydia (both MN4) and Cricetodon meini Freudenthal, 1963 in the MN5 localities of Thymiana A and C, Antonios and Komotini. The two MN4 small mammal assemblages in Aliveri (Euboea island) and Karydia (Northern Greece) have several species in common and Cricetodon aliveriensis is one of them. The aim of this paper is to record and describe this species, the most abundant rodent in the Karydia assemblage, to compare the morphological variation and to discuss the differences in size between the material of Karydia and Aliveri. The results of this study indicate that we deal with one Cricetodon species in Karydia, although more advanced than Cricetodon aliveriensis from Aliveri. This study highlights the importance of a detailed morphological description to the size range of a species. The Karydia material shows a large range in length and width measurements that may indicate heterogeneity of samples. However, the morphological similarity and the normal distribution of the Cricetodon values support the assignment to only one species.Naturali

Morphological analysis of Cricetodon aliveriensis (Rodentia, Mammalia) from the locality of Karydia (Rhodope, Northern Greece)

Cricetodon is present in the early Miocene of Greece in six assemblages, Cricetodon aliveriensis Klein Hofmeijer and de Bruijn, 1988 in Aliveri and Karydia (both MN4) and Cricetodon meini Freudenthal, 1963 in the MN5 localities of Thymiana A and C, Antonios and Komotini. The two MN4 small mammal assemblages in Aliveri (Euboea island) and Karydia (Northern Greece) have several species in common and Cricetodon aliveriensis is one of them. The aim of this paper is to record and describe this species, the most abundant rodent in the Karydia assemblage, to compare the morphological variation and to discuss the differences in size between the material of Karydia and Aliveri. The results of this study indicate that we deal with one Cricetodon species in Karydia, although more advanced than Cricetodon aliveriensis from Aliveri. This study highlights the importance of a detailed morphological description to the size range of a species. The Karydia material shows a large range in length and width measurements that may indicate heterogeneity of samples. However, the morphological similarity and the normal distribution of the Cricetodon values support the assignment to only one species