Table of Content

15 December 2018, Volume 56 Issue 4

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A new species of Saurichthys from the Middle Triassic (Anisian) of southwestern China

WU Fei-Xiang, SUN Yuan-Lin, FANG Geng-Yu

2018, 56(4):  273-294. 

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The saurichthyiform fishes were effective predators and hence the significant consumers in the aquatic ecosystems during the Early Mesozoic. They showed a notable diversification in the Anisian (Middle Triassic)Lagerst？tten of southwestern China. In this contribution, we report a new species of Saurichthys from the Anisian of Yunnan, China, that displays some peculiar modifications of the axial skeleton and the longate body of the group. This new species, Saurichthys spinosa is a small-sized saurichthyid fish characterized by a very narrow interorbital region of the skull roof, an anteriorly expansive and ventrally arched cleithrum, proportionally large abdominal vertebrae lacking neural spines and alternately bearing laterally-stretching paraneural plates, few fin rays in the median fins, and two paralleling rows of needle-like flank scales with strong thorns. This fish hasslimmed down the body by reducing the depth of the head and the epaxial part of the trunk. The elongate paraneural plates inserted in the horizontal septum and the rigid interlocking of the flank scales render the fish a very stiff body, which is compatible with the functional consequence of the obvious decrease of the body (vertebral) segments. This discovery reveals the variability of the axial skeleton and the hydrodynamic properties of the saurichthyiform fishes. These factors, together with the innovations in the locomotion and feeding habit, might have intrinsically effected the evolutionary burst of the eastern Tethyan saurichthyiform fishes during the Anisian, a marked signature of the rapid radiation stage of the biotic recovery after the end-Permian extinction. 

New materials of Choerolophodon (Proboscidea) from Dhok Pathan Formation of Siwaliks, Pakistan

Sayyed Ghyour ABBAS, Muhammad Akbar KHAN, Muhammad Adeeb BABAR, Muhammad HANIF,Muhammad AKHTAR　

2018, 56(4):  295-305. 

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Choerolophodon corrugatus is the only species of the genus Choerolophodon found in the Siwalik Group. Its first appearance is in the Kamlial Formation (Middle Miocene) of the Lower Siwalik Subgroup and it is most abundant in the Dhok Pathan Formation of the Middle Siwalik Subgroup (Late Miocene to Early Pliocene). New remains of Choerolophodon corrugatus have been recovered from the Dhok Pathan type locality and its adjacent areas. The specimens include tusks, mandible and maxillary fragments, and deciduous premolars and permanent molars. The Siwalik species shows great affinity with the European species Ch. pentelici in dentition and differs in the cranial and mandibular characteristics.    

Late Pleistocene proboscideans from Yangjiawan caves in Pingxiang of Jiangxi: with discussions on theStegodon orientalis–Elephas maximus assemblage

TONG Hao-Wen, DENG Li, CHEN Xi, ZHANG Bei ,WEN Jun

2018, 56(4):  306-326. 

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The mammalian fauna from the Yangjiawan Caves in Jiangxi contains more than 40 species, including Stegodon and Elephas, whose age is Late Pleistocene. The 40 pieces of Stegodon fossils include such elements as DP2, DP3, DP4, M1, M3, dp3, m2 and m3, which can be included in the species S. orientalis according to their morphological characters and their dimensions; but with the following specialities: the teeth are relatively small, with thin but wrinkled enamel layer, the mammillae are lesser in number but well defined and equally developed, DP3 and dp3 with larger W/L ratios, and the cement is not well developed. The fossils of Elephas are few, only 2 isolated lamellae whose thickness and size correspond with those of Elephas maximus. In addition, a fragment of tusk (upper incisor) of elephant was also recovered, whose Schreger outer angle is 136°, which falls within the ranges of both Stegodon and Elephas. Therefore, it is difficult to refer it to eitherStegodon or Elephas. This is the first sample of fossil elephant tusk with Schreger outer angle examined in China. The range of S. orientalis covered almost all of the period of Pleistocene in southern China, but the situation forE. maximus is far from clear because of the taxonomic uncertainty of the Early-Middle Pleistocene Elephas (Palaeoloxodon). It is sure that E. maximusbecame popular since Late Pleistocene. According to the study on the origin of the modern species of Asian elephant, the Stegodon-Elephas assemblage in southern China probably has a late Middle-Late Pleistocene age, and definitely with a Late Pleistocene age. The fossils of Stegodon were recovered throughout all the period of Quaternary in southern China, and even appeared in some localities in northern China during the Early Pleistocene. Whereas the elephantid species, including Palaeoloxodon and Elephas, were absent in southern China during the Early Pleistocene epoche, but widely spreaded during the Middle-Late Pleistocene. What should be emphasized is that it isStegodon which used to dominate the proboscidean fauna during the whole period of Pleistocene in southern China, but the last survivor is Elephas even though it was poorly documented in the fossil records, and Stegodon got extinct around the Pleistocene/Holocene boundary.  

New progress on the correlation of Chinese terrestrial Permo-Triassic strata

LIU Jun

2018, 56(4):  327-342. 

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Implications for Late Miocene diet from Diceros gansuensis: starch granules in tooth calculus

CHEN He, WANG Shi-Qi, TAO Da-Wei, XIA Xiu-Min, CHEN Shan-Qin,WU Yan

2018, 56(4):  343-353. 

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Reconstructing the diet of extinct species is a fundamental goal in vertebrate paleobiology. Dental calculus is the calcium phosphate deposits on teeth, which captures a large number of food particles and contains the food information of ancient animal. It is possible to explore ancient animal dietary and investigate the environmental information from dental calculus. A large number of starch granules were found in dental calculus of Dicros gansuensisexcavated from the earliest Late Miocene Guonigou fauna of the Linxia Basin, Gansu Province. It is the first time that starch granules from Late Miocene were found. We classified the ancient starch granules by its morphological characteristics and also analyzed the starch granules of leaves of modern plants around the living environment of D. gansuensis to find modern starch granules and compare them with ancient ones. The results indicate that D. gansuensismay eat not only shrubs leaves, such as the plant from Caprifoliaceae, but also some tree leaves from Juglandaceae (walnut), and maybe some herbs from Ranunculaceae and Polygonaceae. It is consistent with the results of previous morphological studies, and it also provides more information. Our study extends the range of time and object for dental calculus research, and offers more possibilities for research on feeding habits of ancient mammals.