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New early Eocene vertebrate assemblage from western India reveals a mixed fauna of European and Gondwana affinities
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Abstract The Ypresian Cambay Shale Formation at Vastan and Mangrol lignite mines in Gujarat, western India, has yielded a rich vertebrate fauna with numerous taxa of European affinities. Here we report a new, approximately contemporary vertebrate assemblage from two fossiliferous layers in the nearby mine of Tadkeshwar. These layers have yielded a similar mammal fauna with the co-occurrence of the perissodactyl-like cambaytheriid Cambaytherium thewissi, the adapoid primates Marcgodinotius indicus and cf. Asiadapis cambayensis, and the hyaenodontid Indohyaenodon raoi. The presence of these species in both Vastan and Tadkeshwar mines and at different levels suggests that the deposits between the two major lignite seams represent a single land mammal age. Apart from the aforementioned species there is a new, smaller species of Cambaytherium, and a new genus and species of esthonychid tillodont. This fauna also contains the first large early Eocene vertebrates from India, including an unidentified Coryphodon-like pantodont, a dyrosaurid crocodyliform and a new giant madtsoiid snake. Among the Tadkeshwar vertebrates several taxa are of Gondwana affinities, such as Pelomedusoides turtles, dyrosaurids, and large madtsoiids, attesting that the early Eocene was a crucial period in India during which Laurasian taxa of European affinities co-existed with relict taxa from Gondwana before the India-Asia collision. Our results suggest that terrestrial faunas could have dispersed to or from Europe during episodes of contact between the Indian subcontinent and different island blocks along the northern margin of the Neotethys, such as the Kohistan–Ladakh island-arc system. Gondwana taxa might represent remnants of ghost lineages shared with Madagascar, which reached the Indian subcontinent during the late Cretaceous; alternatively they might have come from North Africa and passed along the southern margin of the Neotethys to reach the Indian subcontinent. These dispersals would have been possible as a result of favourable paleogeographic conditions such as the particular Neotethys conformation during the beginning of the early Eocene.
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RBINS Staff Publications 2016
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New equations for the size reconstruction of sturgeon from isolated cranial and pectoral girdle bones
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Measurements on cranial and pectoral girdle bones of 56 museum specimens of modern sturgeon (Acipenser sturio and A. oxyrinchus) were used for the establishment of regression equations allowing back-calculation of size from isolated sturgeon remains. Different curve fittings (power, linear, logarithmic and exponential fit) were modeled to retain the most accurate regression. These were then applied to archaeological sturgeon remains (A. sturio/A. oxyrinchus) from Vlaardingen, a Dutch late Neolithic settlement. The back-calculated lengths ob- tained on the archaeological remains all stayed within the known size ranges of the two species and allowed making inferences on the possible place of capture of the fish. Copyright © 2014 John Wiley & Sons, Ltd. Key words: Acipenser oxyrinchus; Acipenser sturio; archaeozoology; body length estimations; osteometry; Sturgeon
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New euprimate postcrania from the early Eocene of Gujarat, India, and the strepsirrhineehaplorhine divergence
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The oldest primates of modern aspect (euprimates) appear abruptly on the Holarctic continents during a brief episode of global warming known as the Paleocene-Eocene Thermal Maximum, at the beginning of the Eocene (~56 Ma). When they first appear in the fossil record, they are already divided into two distinct clades, Adapoidea (basal members of Strepsirrhini, which includes extant lemurs, lorises, and bushbabies) and Omomyidae (basal Haplorhini, which comprises living tarsiers, monkeys, and apes). Both groups have recently been discovered in the early Eocene Cambay Shale Formation of Vastan lignite mine, Gujarat, India, where they are known mainly from teeth and jaws. The Vastan fossils are dated at ~54.5 Myr based on associated dinoflagellates and isotope stratigraphy. Here, we describe new, exquisitely preserved limb bones of these Indian primates that reveal more primitive postcranial characteristics than have been previously documented for either clade, and differences between them are so minor that in many cases we cannot be certain to which group they belong. Nevertheless, the small distinctions observed in some elements foreshadow postcranial traits that distinguish the groups by the middle Eocene, suggesting that the Vastan primatesdthough slightly younger than the oldest known euprimatesdmay represent the most primitive known remnants of the divergence between the two great primate clades.
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RBINS Staff Publications 2016
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New evidence from a Roman context in Belgium for fish sauce locally produced in northern Gaul
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Fish remains from a mid-2nd century AD context at Tienen (Belgium) are believed to represent the remains of a fish sauce produced in northern Gaul. The observed species spectrum, the reconstructed sizes of the fish, and modern data on the abundance, geographical distribution and size of fish in the surf zone of the Belgian coast and in the estuary of the Scheldt basin, together indicate that the species present in the sauce were captured in the upper reaches of an estuary. Using similar reference data it was also possible to establish that the fish were caught during spring or early summer. After a discussion of the possible fish catching methods used in estuaries during Roman times, the assemblage from Tienen is compared to other Roman finds of locally produced fish sauce that have been reported thus far from sites in Great Britain and Belgium.
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New evidence of the emergence of the East Asian monsoon in the early Palaeogene
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Previous palaeoenvironmental reconstructions have implied that East Asia was dominated by a zonal climate pattern during the Eocene, with an almost latitudinal arid/semiarid band at ~ 30° N. However, this long-standing model has recently been challenged by growing body of multidisciplinary evidence. Some studies indicated that central China was characterized by climatic fluctuations between humid and drier conditions during the Early Eocene, akin to the present East Asian monsoon (EAM) regime. Using palynological assemblages in the Tantou Basin, central China, we quantitatively reconstructed climate changes from the Late Palaeocene to Early Eocene to better understand climate change in central China. Palynological assemblages revealed that the coniferous and broad-leaved mixed forest in this area received no less than 800 mm of annual precipitation and experienced a climate change from warm and wet to relatively cool and dry. According to palaeoclimate curves, a sudden climate change occurred in the Early Eocene, with the mean annual temperature and precipitation decreasing by 5.1 °C and 214.8 mm, respectively, and the climate became very similar to the present climate, which is controlled by the monsoon. Therefore, this significant climate change during the Early Eocene may signal the emergence of the EAM in East Asia.
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RBINS Staff Publications 2022 OA
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New exceptionally well-preserved specimens of “Zangerlia”neimongolensis from Bayan Mandahu, Inner Mongolia, andtheir taxonomic significance
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Two exceptionally well-preserved specimens of “Zangerlia” neimongolensis provide addi-tional information on the structure of the skull, shell and limbs of this taxon. Thesespecimens show that the carapace is more similar to that of Hanbogdemys than was previ-ously recognized. A PAUP analysis results in a single most parsimonious cladogram in whichthe type species of Zangerlia, Zangerlia testudinimorpha is separated from other speciesthat have been included in that genus while “Z.” neimongolensis, “Zangerlia” ukaachelysand “Zangerlia” dzamynchondi and Jiangxichelys are grouped together. Both specimens areexceptional in being preserved in a life-like position: one is preserved with the skull ina retracted position; the other with the head and left forelimb both protracted and in araised position. These positions suggest that they were entombed while still alive. Thusthese specimens provide additional examples of rapid burial of vertebrates in the BayanMandahu locality, most likely from either by sand storms that dumped massive amountsof sand over a short period of time or by collapse of individuals in burrows.
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New extralimital record of a narwhal (Monodon monoceros) in Europe
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RBINS Staff Publications 2018
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New fossils from Tadkeshwar Mine (Gujarat, India) increase primate diversity from the early Eocene Cambay Shale
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Several new fossil specimens from the Cambay Shale Formation at Tadkeshwar Lignite Mine in Gujarat document the presence of two previously unknown early Eocene primate species from India. A new species of Asiadapis is named based on a jaw fragment preserving premolars similar in morphology to those of A. cambayensis but substantially larger. Also described is an exceptionally preserved edentulous dentary (designated cf. Asiadapis, unnamed sp. nov.) that is slightly larger and much more robust than previously known Cambay Shale primates. Its anatomy most closely resembles that of Eocene adapoids, and the dental formula is the same as in A. cambayensis. A femur and calcaneus are tentatively allocated to the same taxon. Although the dentition is unknown, exquisite preservation of the dentary of cf. Asiadapis sp. nov. enables an assessment of masticatory musculature, function, and gape adaptations, as well as comparison with an equally well-preserved dentary of the asiadapid Marcgodinotius indicus, also from Tadkeshwar. The new M. indicus specimen shows significant gape adaptations but was probably capable of only weak bite force, whereas cf. Asiadapis sp. nov. probably used relatively smaller gapes but could generate relatively greater bite forces.
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RBINS Staff Publications 2018
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New fossils of Hyaenodonta (Mammalia) from the Eocene localities of Chambi (Tunisia) and Bir el Ater (Algeria), and the evolution of the earliest African hyaenodonts
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We present and describe new fossils from the Eocene North African localities of Chambi (Tunisia; late Ypresian or early Lutetian) and Bir el Ater (Algeria; latest Bartonian or earliest Priabonian). The specimens from Chambi allow recognizing two recently described hyainailourines: Furodon crocheti and Parvavorodon gheerbranti; these taxa were previously known from the Gour Lazib area (Algeria; late Ypresian or early Lutetian). The new material from Tunisia includes a fragmentary dentary of Parvavorodon that substantially supports the hyainailourine status of this genus and represents the oldest dentary fragment presently known for a juvenile of Hyaenodonta in Africa. The presence of Furodon and Parvavorodon in Chambi strengthens support for the hypothesis of contemporaneity of the Eocene Gour Lazib and Chambi mammalbearing localities. In addition, the find of a typical teratodontine fourth premolar in Chambi testifies to the presence of a small representative of this group. The fossil record in Bir el Ater is scarcer than in Chambi. However, we recognize specimens attributable to a hyainailourine and a teratodontine. The latter is referred as Masrasector cf. ligabuei, and is the oldest record for this genus. We tentatively identify a modification of the hyaenodont fauna in the Maghreb after the “Early Eocene Climatic Optimum” (EECO). This faunal change might be related to the decrease of the global temperature after the EECO event. It appears contemporaneous of a drastic replacement in the composition of the mammal faunas in Africa. Finally, the end of the Eocene (Priabonian) shows an increase in the subfamilial richness amongst hyaenodonts.
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RBINS Staff Publications 2016
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New fossils of paroxyclaenids (Placentalia, Mammalia) from the early Eocene of France shed light on the origin and evolution of these endemic European mammals
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Paroxyclaenidae is an enigmatic archaic group of middle size placental mammals. They are known only from Europe, and are recorded from the early Eocene (Ypresian) to the middle Eocene (Bartonian). Paroxyclaenids are divided into two distinct subfamilies: Paroxyclaeninae and Merialinae. They have been variously placed by different authors in Carnivora, Creodonta, ‘Condylarthra’, and Insectivora, but are considered since 1970’s as members of Pantolesta. The dentition of paroxyclaenids is complete (4 premolars, 3 molars); it is highly specialized, with relatively enlarged posterior premolars, spaced out cheek teeth, but primitive, for instance, in the absence of hypocone on upper molars. The molars decrease in size from M1/m1 to M3/m3; the M3 and m3 are sometimes well reduced. A particularity of the dentition of some paroxyclaenids is the tendency to enlargement and molarisation of the third and fourth upper and lower premolars, generally exceeding the succeeding molars in size. We recently studied unpublished fossils from the first half of the Ypresian: these fossils originate from the French localities of Le Lien (Hérault), Pourcy, Mutigny, Avenay (Marne), and Condé-en-Brie (Aisne). They allow to describe new specimens of Merialus martinae (the oldest paroxyclaenid) and three new species – the oldest paroxyclaenine and two merialines. Their study is the opportunity to review the evolution of this family – the last extensive and comprehensive review of the paroxyclaenids has been published in 1988. The two paroxyclaenid subfamilies – Paroxyclaeninae and Merialinae – are rarely recorded together: this case only occurs in the Paris Basin during the early Eocene (Mutigny, Avenay, Condé-en-Brie). Half of the merialines are present in the Southern European Province, while the paroxyclaenines are only recorded in Northern European Province. The two subfamilies reach their maximum size (+/- 3-4 kg) (e.g., Spaniella, Kopidodon) around the early/middle Eocene boundary (47.8 Myr). However, some smaller paroxyclaenids (body mass around 1 kg) have co-existed together with the larger ones. The small middle Eocene paroxyclaenids, which are as small as the taxa found in the early Eocene, have been the last representatives of the group (Bartonian). The maximum of diversity of the Paroxyclaenids occurred during the Lutetian (middle Eocene). Finally, because the new fossils provide information on the morphology of the earliest paroxyclaenids, their study is the opportunity to question the origin of this group and its relationships among Placentalia. Grant Information: This abstract is a contribution to the project BR/121/A3/PALEURAFRICA funded by the Belgian Science Policy Office.
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RBINS Staff Publications 2017
