Significance of primate petrosal from Middle Eocene fissure-fillings at Shanghuang, Jiangsu Province, People's Republic of China

An isolated petrosal bone belonging to a diminutive primate is reported from Middle Eocene fissure-fills near Shanghuang (southern Jiangsu Province, People's Republic of China), the type locality of several newly described primates (Eosimias sinensis, a basal anthropoid; Adapoides troglodytes, a basal adapinan; Tarsius eocaenus, a congener of extant tarsiers; and Macrotarsius macrorhysis, the first Asian representative of an otherwise exclusively North American genus). Because of its fragmentary condition and unique combination of characters, the Shanghuang petrosal cannot be assigned unambiguously to any of the Shanghuang primate taxa known from dental remains. However, the possibility that the petrosal represents either an adapid or a tarsiid can be dismissed because it lacks defining basicranial apomorphines of these groups. By contrast, the element does present arterial features consistent with its being haplorhine. Deciding between the likeliest candidates for its allocation—Omomyidae and Eosimiidae—is difficult, in part because it is not known what (or even whether) basicranial characters can be used to distinguish these clades. If the Shanghuang petrosal is that of an cosimiid, as both direct and indirect evidence appears to indicate, the following implications emerge: (1) as long suspected on other grounds, anthropoids share a closer evolutionary history with Omomyidae (and Tarsiiformes) than they do with Adapidae (and Strepsirhini); (2) the specialised basicranial anatomy of extant anthropoids and their immediate cladistic relatives is derived from a primitive precursor whose otic morphology was like that of omomyids in most known respects; (3) the evolution of the defining dental and basicranial apomorphies of extant Anthropoidea has been distinctly mosaic in pattern.     

Middle Triassic Xingyi Fauna: Showing turnover of marine reptiles from coastal to oceanic environments

The late Ladinian (Middle Triassic) Xingyi Fauna from the Zhuganpo Member of the Falang Formation yields abundant and well-preserved marine reptiles. Bed-by-bed excavation at Wusha in Xingyi of Guizhou Province reveals two marine vertebrate assemblages in a fossiliferous horizons that span 5.1 m in total thickness. The lower assemblage is marked by the near-shore sauropterygians, including the pachypleurosaur Keichousaurus, the nothosaurians Nothosaurus and Lariosaurus, with a strong paleobiogeographic affinity to western Tethys. The upper assemblage consists of oceanic ichthyosaurs and pistosaurs, including the large shastasaurid ichthyosaur Guizhouichthyosaurus, the euichthyosaur Qianichthyosaurus, pistosaurs Yunguisaurus and Wangosaurus, and the thalattosaur Xinpusaurus, with a closer paleobiogeographic affinity to North America. The coastal pachypleurosaur and nothosaurid sauropterygians disappeared in the upper assemblage, suggesting that they were replaced by an oceanic marine reptile community that emerged. The reptilian composition of the upper assemblage is similar to that of the Guanling Biota, which is of the Early Carnian (Late Triassic) in age and thus somewhat younger than the Xingyi Fauna. The ecological turnover of marine reptiles from near-shore to the open ocean community corresponds to the paleoenvironmental changes indicated by lithofacies analysis, δ¹³C and the global sea level changes.     

Early Eocene lagomorph (Mammalia) from Western India and the early diversification of Lagomorpha

We report the oldest known record of Lagomorpha, based on distinctive, small ankle bones (calcaneus and talus) from Early Eocene deposits (Middle Ypresian equivalent, ca 53 Myr ago) of Gujarat, west-central India. The fossils predate the oldest previously known crown lagomorphs by several million years and extend the record of lagomorphs on the Indian subcontinent by 35 Myr. The bones show a mosaic of derived cursorial adaptations found in gracile Leporidae (rabbits and hares) and primitive traits characteristic of extant Ochotonidae (pikas) and more robust leporids. Together with gracile and robust calcanei from the Middle Eocene of Shanghuang, China, also reported here, the Indian fossils suggest that diversification within crown Lagomorpha and possibly divergence of the family Leporidae were already underway in the Early Eocene.     

A new genus and species of triggerfish from the Middle Eocene of the Northern Caucasus,the earliest member of the Balistidae (Tetraodontiformes)

Until now, the earliest known members of the triggerfish family Balistidae have been two genera from the Oligocene. Herein is described the new balistid Gornylistes prodigiosus gen. et sp. nov. from the uppermost Middle Eocene (Kuma Horizon) of the Northern Caucasus (Gorny Luch locality); it is as thoroughly modern in its bauplan as the taxa of balistids from the Oligocene and more recent periods, and far more advanced morphologically than the several stem taxa of the balistoid + ostracioid clade known from earlier in the Middle and Lower Eocene and from the Upper Paleocene.     

Paleoecology of early middle Eocene bats from Messel,FRG. aspects of flight,feeding and echolocation

By their diversified flight apparatus Messel bats occupied specific flight niches similar to those of extant tropical bats. The small Palaeochiropteryx tupaiodon is considered to be most specialized for hunting close to the ground and for hovering inside dense vegetation. Contrarily, Hassianycteris spp. most likely were high and fast flyers in the open space.

The analysis of gut contents proves that Palaeochiropteryx spp. exclusively fed on small moths and caddis flies, i.e. slow and low flying insects. For P. tupaiodon this confirms the foraging strategy independently from wing morphology. Hassianycteris spp. preyed mainly on beetles or other insects with thick cuticules.

Inner ears of Messel microbats are less specialized compared to those of recent species. Especially P. tupaiodon shows no acoustical specialization with regard to its hunting habitat. Thus, we assume that during the early evolution of bats the development of different flight styles and wing shapes preceded acoustical refinements of the echolocation system.     

Isopollen maps as a tool for the reconstruction of a coastal swamp from the Middle Eocene at Helmstedt (Northern Germany)

Summary In the Middle Eocene lignite bearing succession at Helmstedt, isopollen maps have been constructed from a thin, highly carbonaceous horizon in the interbed between two seams of the Wulfersdorf member. During mining progress this carbonaceous band could be traced in the mine high wall over an area of 2 km by 0.5 km and is considered to represent an isochronous horizon. 28 samples were collected and analyzed. On the basis of the isopollen maps it is possible, to distinguish between allochthonous and autochthonous elements. Ultimately, by comparison of the maps individual plant associations and environmental conditions may be recognized. In case of the carbonaceous horizon of the Wulfersdorf seam group a coastal swamp succession can be traced from a mangrove fringe through a brackish marsh and a freshwater marsh to a mire forest. The distribution of mangrove elements likeRhizophora, Avicennia andNypa in this horizon clearly shows that the shoreline was to the northwest and advanced from there inland to the southeast. A fourth element,Psilodiporites iszkaszentgyoergyi, is restricted in distribution and closely associated with the other known mangrove types and therefore considered here to be a part of the mangrove fringe. Behind the mangrove zone, pollen of Restionaceae and Sparganiaceae as well as fern spores are more abundant than elsewhere in the Wulfersdorf seam section suggesting that a reed-like vegetation with fern and aquatic herbs developed here under rather wet conditions. A hammocky distribution of corresponding plants is indicated by the isopollen map of palms likeArecipites spp. and other elements. The main peat forming vegetation, however, was a mire forest dominated by Fagaceae alternating with a Betulaceae dominated forest including Myricaceae and Juglandaceae.     

豫鼠化石在我国阿尔金地区的发现

记述了在新疆巴音郭楞蒙古族自治州若羌县阿尔金山地区彩虹沟首次发现的豫鼠一新种:阿尔金豫鼠(Yuomys altunensis sp.nov.).其主要特征是臼齿的尺寸较大,比例上较宽,齿冠较高,臼齿的后小尖与后尖明显分开,后脊相对较长,但不完全,次尖明显小于原尖,舌侧内凹伸达臼齿齿冠基部,后齿带与后尖舌侧连;M3后尖为新月形,后齿带较短等.根据豫鼠臼齿的进化趋势和新种臼齿的尺寸较大、齿冠较高和舌侧内凹伸达齿冠基部的特征与Y.cavioides,Y.eleganes和Y.huangzhuangensis相近,但颊齿比例较宽判断,Y.altunensis可能与该3种处于同样的进化阶段或稍进步.其产出的地层时代很可能与它们相近或稍晚,即为晚中始新世或稍晚.     

Eocene fossil rodent assemblages from the Erlian Basin (Inner Mongolia,China): Biochronological implications

Rodents from the Nuhetingboerhe-Huheboerhe area in the Erlian Basin, Inner Mongolia, differ stratigraphically: primitive ctenodactyloids such as Chenomys and Yuanomys are dominant in the upper part of the Nomogen Formation; Tamquammys dominates in the Arshanto Formation; Asiomys, Pappocricetodon, and Yuomys appear in the lower part of the Irdin Manha Formation and Tamquammys is rarer in this formation than in the Arshanto Formation. The assemblage of the upper part of the Nomogen Formation is similar to that of the Lingcha Formation of Hunan, the Wutu Formation of Shandong, the Yuhuangding Formation of Hubei, and the Bumban Member of the Nara-Bulak Formation of Mongolia. The assemblage in the upper part of the Arshanto Formation is correlated with that from the locality Andarak 2 in Kyrgyzstan. The assemblage from the lower part of the Irdin Manha Formation resembles that of the lower part of the Hetaoyuan Formation of Henan.On the basis of the comparison of the rodent assemblages, I consider that the age of upper part of the Nomogen Formation corresponds to the Bumbanian land mammal age. The Bumbanian, Arshantan, and Irdinmanhan land mammal ages are correlated respectively to the early Ypresian, the middle–late Ypresian, and the early Lutetian of the Geological Time Scale. The Bumbanian and Irdinmanhan land mammal ages are also correlated to the early Wasatchian and the early Uintan (or the later Bridgerian) of the North American Land Mammal Ages.     

The laminated lake sediments of the Eckfeld maar (Middle Eocene, Germany): Types of stratification and role of organic matter

Summary The Middle Eocene lake sediments of the Eckfeld maar are situated on the southwestern margin of the Tertiary High-Eifel volcanic field (Germany) and are well known for excellently preserved fossil remains. During a driling campaign in 1996 six well sections were cored at three different locations. Three cores (E1/96, E2/96 and E3/96) penetrated deposition of the central lake facies, which is dominated by laminated organic-rich pelites within the uppermost 40 m. It is the aim of this paper to present a brief survey over the main types of stratification observed within the organic-rich portions of the Eckfeld lake sediments. Based on the varying distribution of mineral and organic matter three sediment sequences are distinguished representing different phases of lake development. The “minerogenic laminites” represent the purely clastic mineral sedimentation in a lake, which was surrounded during this early phase by a tephra rim barren of vegetation. The gradual overgrowth of the tephra rim by vegetation is reflected by the predominance of land plant detritus in the sediments of the “transtion beds”, though the siliciclastic input is still significant. In contrast, the succeeding sequence of the “biogenic laminites” is characterised by the frequent occurrence of centric diatoms (mainly of the planktonic speciesAulacoseira cf.granulata) and Chlorophyceae (mainlyBotryococcus andTetraedron) documenting the increase in autochthonous organic sedimentation in a meromictic lake.     

The oldest representative of Entelodontoidea (Artiodactyla,Suiformes) from the Middle Eocene of Khaichin Ula II,Mongolia, and some evolutionary features of this superfamily

The oldest representative of the family Entelodontidae (suborder Suiformes), Proentelodon minutus gen. et sp. nov, is described from the Middle Eocene Khaichin Ula II Fauna in Mongolia. In addition to the genus Proentelodon, the new subfamily Proentelodontinae includes the genus Eoentelodon from the Middle-Upper Eocene of China, Mongolia, and Kazakhstan. The new data bring clues to the origin and systematic position of Entelodontidae, features of their evolution, dispersal, and changes in taxonomic diversity. They also elucidate the early evolutionary stages of Suiformes.     

The skeleton of early Eocene Cantius, oldest lemuriform primate

A recently discovered partial skeleton of the adapid Cantius trigonodus from the early Eocene Willwood Formation of the Bighorn Basin, Wyoming, documents substantial new information about the anatomy of the oldest lemuriform primates. It is very similar in all features to its descendant, middle Eocene Notharctus, and both exhibit numerous resemblances to certain extant Malagasy lemurs, particularly Lepilemur, Propithecus, Lemur, and Hapalemur griseus. Like these forms, Cantius had relatively long hind limbs and short forelimbs. Forelimb traits (prominent brachialis flange of the humerus, well-developed olecranon process of the ulna, and strong shafts of the ulna and radius) suggest active use of the forelimbs in progression. Specializations in the hind limb (e.g., expanded articular surface of the femoral head, narrow and elevated patellar trochlea and prominent lateral trochlear ridge, posteriorly oriented femoral and tibial condyles, narrow and elongate talus, and hallucal metatarsal with prominent peroneal tubercle) indicate capabilities for leaping and for powerful grasping with an opposable hallux. Cantius was presumably primitive in having a relatively long ischium and much more distal inferior tibial tuberosity than most extant lemurs--traits suggesting that powerful extension of the thigh and flexion at the knee were important in its locomotion and posture. We interpret Cantius as an active arboreal quadruped with a propensity for leaping. The existence of this skeletal structure in one of the oldest primates of modern aspect suggests that it represents the primitive lemuriform morphology.     

First substantial Middle Eocene record of the Lithornithidae (Aves): A postcranial skeleton from Messel (Germany)

A postcranial skeleton of a representative of the palaeognathous Lithornithidae (Aves) is described from the Middle Eocene of Messel in Germany. The specimen is slightly smaller than Lithornis plebius from which it, however, differs in limb bone proportions. It constitutes the latest fossil record of the Lithornithidae in Europe, whose only other Middle Eocene record is a fragmentary tibiotarsus from North America.     

Sedimentology and taphonomy of sirenian remains from the Middle Eocene of the Pamplona Basin (Navarre, western Pyrenees)

Sirenian vertebrae and ribs have been recently discovered from two Middle Eocene localities of the Pamplona Basin, Navarre (western Pyrenees). These outcrops correspond to different lower Bartonian lithostratigraphic units: the lower part of the Pamplona Marl Formation (Uztarrotz site) and the upper part of the Ardanatz Sandstone (Ardanatz site). The former represents a deep and low-energy sea floor far away from a deltaic slope; the Ardanatz environment probably corresponds to a semi-closed deltaic bay periodically affected by catastrophic floods (i.e., fluvial hyperpycnal flows). The presence of epibiontic activity suggests that the bones were exposed for a while prior to the burial. The histological structures are well preserved except in the peripheral region, where tubular-like microstructures filled by pyrite and iron oxides probably correspond to microbial bioerosion. The major mineral component of the fossil bones is francolite (carbonate fluorapatite). In the Ardanatz samples there is evidence of secondary francolite due to the late replacement of original carbonate fluorapatite through internal fractures. The Ardanatz and Uztarrotz sirenian fossils do not show any evidence of reelaboration. They have similar sum of rare earth elements (REE) concentrations relative to the host rock, but comparatively lower than in other vertebrate fossil bones. This feature may be due to the dense compact structure of pachyosteosclerotic sirenian bones.     

Mammalian cortical granules: Contents,fate, and function

Recent studies have extended our knowledge regarding the contents of mammalian cortical granules (CG) and their function in postfertilization events. Cytochemical staining has demonstrated the presence of carbohydrates within mammalian CG, and lectin-binding studies have shown that these carbohydrates include α-Dmannose, α-D-GalNAc, and galactose residues in the hamster, α-D-mannose in the mouse and cat, and β-D-Gal(1,3)-D-GalNAc in the pig. Following fertilization and artificial activation, mannosylated material is released from CG and can be found on the oolemma and within the perivitelline space (PVS) of hamster oocytes. Fertilized or artificially activated rabbit, mouse, and human oocytes also release mannosylated, fucosylated and sialylated, and fucosylated material, respectively, which localizes to the oolemma. These glycosylated materials are probably of CG origin, although they have not been directly localized to the CG in rabbit, mice, and humans. The function(s) of the glycosylated material released from mammalian oocytes is not known, although it may participate in blocking polyspermy at the level of the plasma membrane, PVS, and/or zona pellucida (ZP), or it may facilitate preimplantation embryonic development. Proteinases, including tissue plasminogen activator, are also released from mammalian oocytes following fertilization and artificial activation, suggesting that they are of CG origin. These proteinases modify the ZP such that it is no longer receptive to sperm, and some proteinases have been suggested to bring about ZP hardening (an increased resistance to denaturing agents) by an unknown mechanism. Mouse ZP may also be hardened by an ovoperoxidase (cross-links tyrosine residues) cytochemically identified in mouse CG and CG exudate. The phenomena of ZP hardening in mammalian zygotes is not well understood but is likely to function in blocking polyspermic penetration of the ZP and/or in protecting embryos during preimplantation development. Recently, a 75 kD protein (p75) has been immunocytochemically localized to mouse CG and to the PVS of fertilized oocytes and two-cell embryos. The identity and function of p75 remains to be determined. Heparin binding placental protein may also be a CG component, since it is released from hamster oocytes following fertilization. It has not, however, been directly demonstrated to be a CG component, and its functions in fertilization and/or early embryonic development have yet to be defined. © 1994 Wiley-Liss, Inc.     

Zhailimeryx, A New Lophiomerycid Artiodactyl (Mammalia) from the Late Middle Eocene of Central China and the Early Evolution of Ruminants

A new genus and species of primitive selenodont artiodactyl, Zhailimeryx jingweni, occurs in the late middle Eocene Zhaili Member of the Heti Formation, Yuanqu Basin, Shanxi Province, China. A phylogenetic analysis of dental characters suggests that Zhailimeryx is closely related to Lophiomeryx and other lophiomerycid ruminants of Asia and Europe. Zhailimeryx and other Eocene records of Lophiomerycidae from Asia support an Asian origin for this family, followed by dispersal into Europe both before and after the Grande Coupure. Morphological evidence from Zhailimeryx suggests that ruminant artiodactyls had already undergone substantial diversification prior to the late middle Eocene, and it reopens the issue of whether the higher taxa Tragulina and Pecora are valid expressions of ruminant phylogeny.     

Reassessment of the Early–Middle Eocene biomagnetochronology based on evidence from the Gorrondatxe section (Basque Country, western Pyrenees)

Thirteen Lower–Middle Eocene (Ypresian–Lutetian) successions, including the Gorrondatxe section in the western Pyrenees, show biomagnetostratigraphic correlation schemes that do not agree with the current standard framework. The main discrepancy concerns the position of the boundary between planktonic foraminiferal Zones P9 (=E7, approximately) and P10 (=E8, approximately), which was thought to occur within calcareous nannofossil Subzone CP12a and at the boundary between magnetic polarity Chrons C22n and C21r. However, in the differing correlation scheme the boundary between Zones P9 (=E7) and P10 (=E8) occurs close to the base of Subzone CP13a and to the boundary between Chrons C21n and C20r. An attempt at a new Ypresian–Lutetian boundary biomagnetochronology is made based on data from the Gorrondatxe section, which shows that the boundary between Zones P9 (=E7) and P10 (=E8) is 3.1 Myr younger than hitherto considered. Therefore, the duration of the Early Eocene, most commonly defined according to this planktonic foraminiferal zonal boundary, has generally been underestimated over the last four decades.     

A Probable Diatryma Track from the Eocene of Washington: An Intriguing Case of Controversy and Skepticism

A large tridactyl track from the Franklin Series of the Eocene Puget Group has been named Ornithoformipes controversus ichnogen et ichnosp. nov. and is attributed to a large ground-dwelling Diatryma or a Diatryma-like bird. The isolated footprint clearly shows that the trackmaker had broad semi-circular unguals and feet that show several correspondences with the foot morphology inferred for Diatryma and related forms. The age of the footprint is estimated at about 45 million years, which is about 5 million years younger than known Diatryma body fossils. The sedimentary geology context of the track is consistent with an interpretation of the trackmaker as a large herbivore that lived in well-vegetated areas.     

A Rich and Highly Endemic Decapod Crustacean Fauna from the Middle Jurassic of North-east France

Decapod crustaceans are relatively widespread in Jurassic deposits of Europe and a small number have been collected from the north-east of France. A new fossil of a macrurous decapod assigned to Eryma burgundiaca sp. nov., an erymid lobster, is described from this area and comparisons are made with closely allied species from Europe. Probable pagurid anomurous decapods are represented by Orhomalus magnificus sp. nov., Palaeopagurus acutus sp. nov. and Palaeopagurus neraudeaui sp. nov. No brachyurous decapods are presently known from the fauna. Based on the associated ammonites, the material is considered to be Callovian in age.