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1. chinaXiv:202004.00001 [pdf]

Reappraisal of Serridentinus gobiensis Osborn & Granger?and Miomastodon tongxinensis Chen:the validity of Miomastodon

WANG Shi-Qi; ZHANG Xiao-Xiao; LI Chun-Xiao?
Subjects: Biology >> Zoology

The elephantimorph proboscideans, Serridentinus gobiensis Osborn & Granger, 1932, and Miomastodon tongxinensis Chen, 1978, from the Middle Miocene of northern China, were revised as Zygolophodon gobiensis (Osborn & Granger, 1932). However, their phylogenetic positions are still being debated because of their intermediate morphology between the typical bunodont (Gomphotheriidae) and zygodont (Mammutidae) elephantimorphs. In the present paper, we compare their dental and mandibular morphology with that of the Eurasian Z. turicensis, Gomphotherium subtapiroideum, and G. tassyi, as well as the North American Mio. merriami and G. productum. It appears that S. gobiensis and Mio. tongxinensis share with Mio. merriami the slightly more bunodont molar morphology than that of Z. turicensis, e.g., the thicker enamel, thicker pretrite crescentoids, higher interlophid enamel pillars in buccal view, and the narrower contour majorly caused by the narrower posttrite half loph(id)s. S. gobiensis and Mio. merriami also possess an “erected oval cross-sectioned mandibular tusk”, in which the cross-section is mediolaterally compressed (dorsoventral diameter being larger than the mediolateral one). Whereas, in Z. turicensis and G. productum, the mandibular tusk is “laid oval cross-sectioned”, in which the cross-section is dorsoventrally compressed (dorsoventral diameter is smaller than the mediolateral one). Therefore, it is reasonable to revive the genus Miomastodon Osborn, 1922, which contains the species that were previously attributed to Zygolophodon, but they have relatively bunodont molar morphology (i.e., the robust type of the Z. turicensis group). The mandibular tusk with erected?oval cross-section seems to be a synapomorphy of Miomastodon species. Furthermore, the molar morphology of G. subtapiroideum and G. tassyi also exhibits intermediate status between the typical bunodonts and zygodonts. However, the mandibular symphysis of G. subtapiroideum and G. tassyi is stronger than that of Miomastodon, and the mandibular tusk is pyriform cross-sectioned. The validity of Miomastodon and G. subtapiroideum/tassyi obscures the boundary between the Gomphotheriidae and Mammutidae, and suggests that the evolutions of the Gomphotheriidae and?Mammutidae are deeply involved in with each other, rather than straightforwardly detached. This phenomenon has been revealed by a collagen sequence analysis among Notiomastodon, Mammut, and extant elephants, which should be further studied.

submitted time 2020-03-31 From cooperative journals:《古脊椎动物学报》 Hits4559Downloads528 Comment 0

2. chinaXiv:202004.00002 [pdf]

New material of Cervidae (Artiodactyla, Mammalia) from?Xinyaozi Ravine in Shanxi, North China

DONG Wei; BAI Wei-Peng; PAN Yue; LIU Wen-Hui
Subjects: Biology >> Zoology

Many cervid specimens were uncovered during the field exploration for Nihewan beds?at the beginning of the 1980s from Taijiaping, Shuichongkou and Dazhuangke localities along?Xinyaozi Ravine at Nangaoya Township of Tianzhen County, Shanxi Province in North China.?Recent studies on the cervid material identified seven species of Cervidae in total: Muntiacus?bohlini, Cervavitus cf. C. huadeensis, Axis shansius, Nipponicervus elegans, Elaphurus?davidianus predavidianus, E. bifurcatus from the Early Pleistocene deposits at Taijiaping and?Shuichongkou localities, and Cervus (Elaphus) elaphus from uncertain horizon at Dazhuangke. At?least the previous six species of cervids were from Nihewan Formation (Nihewanian or equivalent?to European middle and late Villafranchian), i.e. the Early Pleistocene, in Sangganhe Basin area.Cervavitus cf. C. huadeensis and A. shansius were survivors from the Late Neogene; M. bohlini,N. elegans, E. davidianus predavidianus and E. bifurcatus are new forms of the Early Pleistocene.If Dazhuangke horizon can be dated as those of Shuichongkou and Taijiaping localities, the appearance of elaphoid cervids could be traced back to the Early Pleistocene, and the evolution of?elaphoid antler would start from absence to presence of bez tine. The presence of Elaphurus and?Nipponicervus in mainland China and Japanese archipelago implies further that the sea level was?dropped down that these cervids could migrate from the mainland to the islands. The abundance?of folivorous cervid specimens in the Xinyaozi Ravine area indicates the existence of a certain?scale of forested environment in Sangganhe Basin area during the Early Pleistocene.

submitted time 2020-03-31 From cooperative journals:《古脊椎动物学报》 Hits4076Downloads458 Comment 0

3. chinaXiv:202004.00003 [pdf]

A new species of Amynodontopsis (Perissodactyla:?Amynodontidae) from the Middle Eocene of Jiyuan,?Henan, China

WANG Xiao-Yang; WANG Yuan-Qing; ZHANG Rui; ZHANG Zhong-Hui; ?LIU Xiao-Ling; REN Li-Ping
Subjects: Biology >> Zoology

An adult amynodont skull, collected from the Middle Eocene Niezhuang Formation of Jiyuan Basin (Henan, China), is recognized as a new species Amynodontopsis jiyuanensis sp. nov. The specimen possesses the typical features of the genus Amynodontopsis, such as a dolichocephalic skull with elevated roof, premaxilla-nasal contact, large preorbital fossa extending posteriorly medial to the orbit, inner surface of anterior orbital bar concave in continuation with the preorbital fossa, antecrochet usually presented on M1, and metastyle of M3 strongly deflected labially. A. jiyuanensis is diagnosed by a combination of the following characters: long nasals, nasal process of premaxilla extending far back laterally below the nasal and excluding the maxilla from the border of external nares, nasal notch above the post-canine diastema, more transverse and proportionally longer protoloph and metaloph on upper molars. Comparison with known species of Amynodontopsis indicates that it is the most primitive one in the genus, due to the possession of primitive characters. Associated fossil mammals support a correlation of the strata bearing A. jiyuanensis with the Shara Murun Formation of the Erlian Basin, Nei Mongol, China, namely the Middle Eocene Sharamurunian Asian Land Mammal Age (ALMA), prior to all other known Amynodontopsis species. The earlier geologic age and primitive morphological features of A. jiyuanensis suggest that Amynodontopsis has an Asian origin in the Middle Eocene and later immigrated into North America.

submitted time 2020-03-31 From cooperative journals:《古脊椎动物学报》 Hits4284Downloads469 Comment 0

4. chinaXiv:201908.00095 [pdf]

First report of immature feathers in juvenile?enantiornithines from the Early Cretaceous Jehol avifauna

Jingmai K. O’CONNOR; Amanda FALK; WANG Min; ZHENG Xiao-Ting
Subjects: Biology >> Zoology

Molting—the process replacing one plumage with another—is a critically important?biological function in Aves. This process annually replaces the feather coat, damaged by normal?wear and tear, produces ontogenetic changes in feathering, and produces alternate breeding?plumages associated with reproductive activity in adults. Immature, growing feathers are?encased in a keratinous sheath, giving them a narrow, tubular, and featureless appearance. The?complete loss of the sheath indicates the feather is mature. Despite the wealth of integumentary?data published from the Jehol Biota, immature feathers have never been definitively reported,?although they may potentially be preserved in a juvenile specimen of the non-avian oviraptorosaur?theropod dinosaur Similicaudipteryx from the 120 Ma Jiufotang Formation. A developing?feather has been reported in a 99 Ma enantiornithine neonate preserved in Burmese amber, in?which three-dimensional preservation makes interpretations of integumentary structures more?straightforward. Here we report on probable immature feathers in four juvenile enantiornithines?(Aves: Ornithothoraces) from the Jehol Group. As observed in developing feathers in extant?birds, the purported immature fossil feathers appear proximally narrow and featureless with?barbs protruding only distally. Based on our observations, we suggest that similar-appearing?feather structures preserved on the manus and tibiotarsus in the holotype of the enantiornithine?Cruralispennia multidonta may alternatively be interpreted as immature feathers. The presence?of immature feathers in combination with sexually dimorphic ornamental feathers in juvenile?enantiornithines suggests the complex molting patterns of Neornithes, in which such ornaments?only appear after several years (following several molts) when reproductive activity is achieved,?are limited to a subset of crownward avians.

submitted time 2019-08-27 From cooperative journals:《古脊椎动物学报》 Hits6144Downloads493 Comment 0

5. chinaXiv:201908.00118 [pdf]

Five new species of Arvicolinae and Myospalacinae from the?Late Pliocene?Early Pleistocene of Nihewan Basin

ZHENG Shao-Hua; ZHANG Ying-Qi; ?CUI Ning
Subjects: Biology >> Zoology

The Nihewan Basin has been well known for its Cezonoic fossiliferous fluviolacustrine deposits and paleolithic sites for almost a century. There have been considerable research efforts devoted to the understanding of the geology, chronology, and stratigraphy of this?complex of sedimentary body. The current fundamental problem lies in the chronological aspect?of the Nihewan Beds. Arvicolinae and Myospalacinae are two groups of rodents characterized?by rapid evolutionary rates and quantifiable evolutionary trends, and hence particularly helpful?in Late Cenozoic biostratigraphic correlations. Therefore, we briefly describe three new species?of Arvicolinae and two new species of Myospalacinae that mainly came from the selected?sections in the Nihewan Basin. Hopefully, they would contribute towards the establishment of the?biostratigraphic framework of the Nihewan Basin and provide new evidence on the chronological?understanding of the Nihewan Beds from an evolutionary point of view.

submitted time 2019-08-26 From cooperative journals:《古脊椎动物学报》 Hits6779Downloads544 Comment 0

6. chinaXiv:201908.00119 [pdf]

New gobiconodontid (Eutriconodonta, Mammalia) from?the Lower Cretaceous Shahai and Fuxin formations,?Liaoning, China

KUSUHASHI Nao; WANG Yuan-Qing; ?LI Chuan-Kui; JIN Xun
Subjects: Biology >> Zoology

Eutriconodontans are one of the key members of mammals to our understanding of the evolution and transition of mammalian fauna in Asia during the Cretaceous. Two gobiconodontid?and two triconodontid species have previously been reported from the upper Lower Cretaceous?Shahai and Fuxin formations. Here we describe two additional eutriconodontans from the?formations, Fuxinoconodon changi gen. et sp. nov. and ?Gobiconodontidae gen. et sp. indet.?This new species is attributed to the Gobiconodontidae, characterized by having an enlarged?first lower incisor, reduction in the number of incisors and premolariforms, proportionally large?cusps b and c being well distant from cusp a on the molariforms, presence of a labial cingulid,?and a unique mixed combination of molariform characters seen on either the first or the second,?but not both, generations of molariforms in Gobiconodon. Together with the four known species,?eutriconodontans remained diverse to some extent in the late Early Cretaceous in Asia, although?their family-level and generic level diversity appears to have been already reduced at that time.

submitted time 2019-08-26 From cooperative journals:《古脊椎动物学报》 Hits7039Downloads554 Comment 0

7. chinaXiv:201908.00120 [pdf]

New gobiconodontid (Eutriconodonta, Mammalia) from?the Lower Cretaceous Shahai and Fuxin formations,?Liaoning, China

KUSUHASHI Nao; WANG Yuan-Qing; ?LI Chuan-Kui; JIN Xun
Subjects: Biology >> Zoology

Eutriconodontans are one of the key members of mammals to our understanding of the evolution and transition of mammalian fauna in Asia during the Cretaceous. Two gobiconodontid?and two triconodontid species have previously been reported from the upper Lower Cretaceous?Shahai and Fuxin formations. Here we describe two additional eutriconodontans from the?formations, Fuxinoconodon changi gen. et sp. nov. and ?Gobiconodontidae gen. et sp. indet.?This new species is attributed to the Gobiconodontidae, characterized by having an enlarged?first lower incisor, reduction in the number of incisors and premolariforms, proportionally large?cusps b and c being well distant from cusp a on the molariforms, presence of a labial cingulid,?and a unique mixed combination of molariform characters seen on either the first or the second,?but not both, generations of molariforms in Gobiconodon. Together with the four known species,?eutriconodontans remained diverse to some extent in the late Early Cretaceous in Asia, although?their family-level and generic level diversity appears to have been already reduced at that time.

submitted time 2019-08-26 From cooperative journals:《古脊椎动物学报》 Hits7176Downloads531 Comment 0

8. chinaXiv:201906.00053 [pdf]

New material of thelodonts from Lochkovian(Lower Devonian) of Qujing, Yunnan, China

CUI Xin-Dong(1,2,3); LI Qiang(4); QIAO Tuo(1,2); ZHU Min(1,2,3)
Subjects: Biology >> Zoology

We reconstructed a wealth of three-dimensional virtual models of vertebrate microremains from the Xitun Formation and lower part of the Xishancun Formation (Lochkovian,Lower Devonian) of Qujing, Yunnan by means of high-resolution computed tomography. One genus (Parathelodus) and seven species (P. trilobatus, P. asiaticus, P. cornuformis, P. scitulus, P. xitunensis sp. nov., P. wangi sp. nov. and P. liaokuoensis sp. nov.) of thelodonts are described. The new discovery extends the stratigraphic distribution of Parathelodus from the Xitun Formation and the upper part of the Xishancun Formation to the lower part of the Xishancun Formation, the horizon close to the Silurian-Devonian boundary. The three new species, P. xitunensis, P. wangi and P. liaokuoensis, enhance our knowledge of the thelodont diversity from the Early Devonian of China.

submitted time 2019-06-17 From cooperative journals:《古脊椎动物学报》 Hits6533Downloads402 Comment 0

9. chinaXiv:201906.00025 [pdf]

The tetrapod fauna of the upper Permian Naobaogou?Formation of China— 4. the diversity of dicynodonts

LIU Jun
Subjects: Biology >> Zoology

The Permian dicynodont records were previously rare in North China, but many?dicynodont specimens have been collected from the Naobaogou Formation in Daqingshan area,?Nei Mongol since 2009. Among these specimens, seven morphotypes have been identified, and?they may represent seven different species: two of them are closely related to Daqingshanodon?limbus, three or four are closely related to Jimusaria sinkianensis, and one may be closely related?to Turfanodon. This study shows the dicynodonts also have a high diversity at the species level in?North China.

submitted time 2019-06-11 From cooperative journals:《古脊椎动物学报》 Hits6636Downloads483 Comment 0

10. chinaXiv:201906.00026 [pdf]

Molecular clock dating using MrBayes

ZHANG Chi
Subjects: Biology >> Zoology

This paper provides an overview and a protocol of molecular clock dating using?MrBayes. Two modern approaches, total-evidence dating and node dating, are demonstrated using?a truncated dataset of Hymenoptera with molecular sequences and morphological characters. The?similarity and difference of the two methods are compared and discussed. Besides, a non-clock?analysis is performed on the same dataset to compare with the molecular clock dating analyses.

submitted time 2019-06-11 From cooperative journals:《古脊椎动物学报》 Hits2319Downloads462 Comment 0

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