Paleogene Of Asia Research Articles

First recognition of the extinct eudicot genus Palibinia in North America: Leaves and fruits of Palibinia comptonifolia (R.W.Br.) comb. nov. from the Eocene of Utah and Colorado, USA

AbstractNewly investigated leafy twigs bearing axillary fruits from the Eocene Parachute Creek Member of the Green River Formation in eastern Utah, USA, have provided more information on the species previously attributed to the Proteaceae as Banksia comptonifolia R.W.Br. The leaves are simple, estipulate with short petioles, and elongate laminae with prominent angular nonglandular teeth. The laminae have a thick midvein and pinnate craspedodromous secondaries, and are distinctive in the presence of a thick, often coalified, marginal rim. Vegetative and reproductive buds occur in the axils of the leaves. These features indicate that the species belongs to Palibinia Korovin—an extinct Eudicot genus previously known only from the Paleogene of Asia and Europe. Small pedicellate ovoid fruits 1.5–2.2 mm wide are borne in fascicles of three and are seen to be capsules with four apical valves. Despite the specific epithet referring to similarity of the foliage to that of Comptonia (Myricaceae), the fasciculate inflorescence organization with axillary flowers is quite distinct from the catkins characteristic of that family. Assignment to Banksia or other Proteaceae with complex inflorescences and follicular fruits is also problematic. Additionally, MacGinitie′s transfer of the species to Vauquelinia of the Rosaceae is contradicted by the lack of stipule scars on the twig and by differences in leaf venation and floral morphology. We transfer the species to Palibinia comptonifolia (R.W.Br.) comb. nov., but its familial affinity within the Pentapetalae remains uncertain. This new occurrence augments records from the Paleogene of Turkmenistan, Kazakhstan, China, England, and Germany.

Fossil infructescence from southwestern China reveals Paleogene establishment of Cladrastis in Asia

While a recent molecular phylogeographical study shows that, Cladrastis, a small woody genus in the bean family (Leguminosae), may have been established in Asia after the middle to late Eocene, fossils of the genus have not been previously documented in the Paleogene of Asia. Here we report an infructescence and four fossil fruits of Cladrastis from the Paleogene of southeastern Yunnan, China, which we described as a new species, C. haominiae, and this represents the first Paleogene record of Cladrastis in Asia. These fossils are characterized by a long stipe, an acuminate or acute proximal/distal end, wide sutures, and elliptical seed(s) nearly parallel or forming a small angle to the long axis of the fruit. Our finding supports the Paleogene establishment of Cladrastis in Asia and provides new significant evidence for the Paleogene origin of Yunnan biodiversity.

A swan-sized anseriform bird from the late Paleocene of Mongolia

ABSTRACTThe early evolutionary history of waterfowl (Anseriformes) is poorly understood. Aside from the morphologically aberrant Presbyornithidae, the only other known early Paleogene anseriform taxon is Anatalavis oxfordi from the early Eocene of England. Here, I describe two bones from the late Paleocene of southern Mongolia (localities Naran-Bulag and Tsagaan-Khushuu), which belong to a very large swan-sized swimming waterfowl (Anseriformes) and are described as Naranbulagornis khun, gen. et sp. nov. This is the first non-presbyornithid anseriform bird found in the early Paleogene (Paleocene through early Eocene) of Asia and one of the few currently known Paleocene birds from Central Asia. It is also the largest volant bird from the Paleogene of Asia. Naranbulagornis khun documents a mosaic of autapomorphic and plesiomorphic features that are otherwise present in modern Anhimidae, Anseranatidae, and Anatidae, indicating a greater morphological diversity of early Cenozoic anseriforms than previously thought. The new taxon is morphologically closer to Anatoidea than to Presbyornithidae and represents the earliest global evidence of a spatial coexistence between presbyornithids and other basal waterfowl during the early Paleogene.

A large mimotonid from the middle Eocene of China sheds light on the evolution of lagomorphs and their kin.

Mimotonids share their closest affinity with lagomorphs and were a rare and endemic faunal element of Paleogene mammal assemblages of central Asia. Here we describe a new species, Mimolagus aurorae from the Middle Eocene of Nei Mongol (China). This species belongs to one of the most enigmatic genera of fossil Glires, previously known only from the type and only specimen from the early Oligocene of Gansu (China). Our finding extends the earliest occurrence of the genus by at least 10 million years in the Paleogene of Asia, which closes the gap between Mimolagus and other mimotonids that are known thus far from middle Eocene or older deposits. The new species is one of the largest known pre-Oligocene Glires. As regards duplicidentates, Mimolagus is comparable with the largest Neogene continental leporids, namely hares of the genus Lepus. Our results suggest that ecomorphology of this species was convergent on that of small perissodactyls that dominated faunas of the Mongolian Plateau in the Eocene, and probably a result of competitive pressure from other Glires, including a co-occurring mimotonid, Gomphos.

Systematics and Phylogeny of Paleocene-Eocene Nyctitheriidae (Mammalia, Eulipotyphla?) with Description of a new Species from the Late Paleocene of the Clarks Fork Basin, Wyoming, USA

Nyctitheriidae is a diverse group of small, insectivorous mammals from the Paleogene of Asia, North America, and Europe that have alternately been linked to Eulipotyphla (shrews, moles, hedgehogs, solenodons), Euarchonta (primates, tree shrews, dermopterans), or Chiroptera (bats). Even intrafamilial relationships are poorly understood, resulting in ambiguity regarding morphological character polarity critical for evaluating supraordinal relationships and paleobiogeographic patterns. To help address this issue, we performed a cladistic analysis of 51 North American, European, and Asian nyctitheriid species, including a new nyctitheriid, Plagioctenodon thewisseni sp. nov. from the late Paleocene of Wyoming, using 66 characters derived from dental morphology. Although the oldest nyctitheriids are found in North America, the resulting most-parsimonious cladograms support an Asian origin of the family with dispersal into North America by the early Paleocene. Among North American and European groups, the subfamilies Nyctitheriinae and Amphidozotheriinae, and the genera Leptacodon and Saturninia are not monophyletic and require future study and revision. The multi-species genera Nyctitherium, Plagioctenodon (including P. thewisseni), Plagioctenoides, Cryptotopos, and Euronyctia are found to be monophyletic, whereas Wyonycteris is paraphyletic, having Pontifactor bestiola nested within it. The earliest known European nyctitheriids (Leptacodon nascimentoi, Placentidens lotus, Plagioctenodon dormaalensis, Wyonycteris richardi) appear in the early Eocene and are each found in an otherwise strictly North American clade consisting of either solely Paleocene or a combination of Paleocene and Eocene taxa, suggesting at least four earliest Eocene dispersals between North America and Europe.

The first ‘true’ Adocus (Testudines, Adocidae) from the Paleogene of Asia

ABSTRACT This paper describes a new species of the genus Adocus (A. inexpectatus, sp. nov.), based on an almost complete shell from the upper Eocene Youganwo (= Youkanwo) Formation of the Maoming Basin, China. The inclusion of A. inexpectatus in a phylogenetic analysis of Adocusia resulted in a polytomy with Adocus aksary and A. amtgai (both from the Upper Cretaceous of Asia). This clade formed a polytomy with the North American species of Adocus. Like other ‘true’ Adocus, A. inexpectatus has overlapping of the marginals onto the costals in the middle and posterior parts of the carapace and sculpturing of the shell surface with small grooves and pits. Thus, A. inexpectatus represents the first ‘true’ Adocus from the Paleogene of Asia. Other specimens from the Paleogene of Asia that have been referred to Adocus, characterized by shell sculpturing with small dots and unknown condition of the marginal/costal overlapping, are distinct from ‘true’ Adocus and herein referred to as ‘Adocus’ spp. Here we also report the presence of ‘Adocus’ from the Paleocene of North America. Our study indicates that the evolutionary and biogeographic history of the Adocidae was more complicated than considered previously, including previously unrecognized dispersal events between Asia and North America. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

The first fossil owls (Aves: Strigiformes) from the Paleogene of Asia and a review of the fossil record of Strigiformes

The fossil record of owls (Strigiformes) is one of the most extensive among the neornithine birds, yet at the same time largely restricted geographically to Europe and North America. Various fossil owls are known from the Paleocene (ca. 60 Ma) to Recent. Here we present the first taxonomic description of new species of Paleogene owls from Asia, two new taxa from the Eocene and Oligocene of Mongolia. The anatomy of Heterostrix tatsinensis gen. et sp. nov., represented by a complete Early Oligocene tarsometatarsus, sheds light on the evolution of perching adaptations in these birds and expands the family diversity of this order. Eostrix tsaganica sp. nov. from the Early Eocene extend the known range of the protostrigid genus Eostrix into Asia (the other known species come from Europe and western North America). The paper also provides a review of the fossil record of owls, which gives evidence for the Late Cretaceous evolutionary radiation of this lineage. In spite of the absence of specimens from the Mesozoic, fossil owl collector-effort (since the 1860s) suggests that, in contrast to many other avian clades, the fossil record of these birds is complete enough for biological signal to be extracted.

SYSTEMATIC STATUS OF ASIAN “PTERODON” AND EARLY EVOLUTION OF HYAENAELURINE HYAENODONTID CREODONTS

We establish a new genus of a hyaenaelurine hyaenodontid (Creodonta: Mammalia), Orienspterodon for “Pterodon” dahkoensis, which is known from three late middle Eocene localities in central and southern China and Myanmar. This paper provides a full description of the species and a comment on the early evolution of Hyaenaelurinae. Some features of Orienspterodon (p2–p3 without an anterior accessory cuspulid, lesser reduction of the m3 talonid relative to m1–m2 talonids, double-rooted P3, and better fusion of the paracone and metacone on M1) confirm that O. dahkoensis is distinct from Pterodon. Orienspterodon differs from the other specialized hyaenodontids from the Paleogene of Asia in being a hyaenaelurine, in being unrelated to Hyaenodon, and in having a geographical distribution in the southern part of the continent. Orienspterodon represents the earliest fossil records of Hyaenaelurinae, and some features (small metaconid on m3, basined talonid on all lower molars, a short and more diagonally oriented metastyle, large size, better fused paracone and metacone) indicate an early branching of this genus from the other hyaenaelurines.

New primates from the late Eocene of Thailand: a contribution to primate diversity in the Paleogene of Asia

We report the discovery of two new primates from the late Eocene Krabi Basin, southern Thailand. One isolated upper molar displays morphological features (protocone united with hypocone by the prehypocrista, postprotocrista extended distobuccally) suggesting possible phylogenetic relationships with Amphipithecidae, while an isolated lower molar is tentatively referred to as a new tarsiiform, mainly on the basis of its paraconid and entoconid morphology. Although very scarce, these remains expand the record of Paleogene primates in Southeast Asia, and testify to their successful radiation in that area.

The occurrence of bothriodontines (Artiodactyla, Mammalia) in the Paleogene of Asia with special reference to Elomeryx: Paleobiogeographical implications

Anthracotheriid remains from several Paleogene localities of central and eastern Asia have been re-examined. Several fossil remains attributed to the genera Bothriodon, Brachyodus and Hyoboops can be referred to Elomeryx which extends the geographical distribution of the genus to the whole area of Asia. These results demonstrate the role that Asia played in the biogeographical history of mammals and further support the proposed origin of North American Elomeryx from an Asian ancestor.

Cenozoic Mammals of North America: Geochronology and Biostratigraphy, Michael O. Woodburne, ed.; The Paleogene of Asia: Mammals and Stratigraphy, Donald E. Russell and Zhai Ren-jie. [Reviews

Cenozoic Mammals of North America: Geochronology and Biostratigraphy, Michael O. Woodburne, ed.; The Paleogene of Asia: Mammals and Stratigraphy, Donald E. Russell and Zhai Ren-jie. [Reviews