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    20 June 2022, Volume 60 Issue 3
    Xitunaspis, a new eugaleaspid fish (Eugaleaspiformes, Galeaspida) from the Lower Devonian of Qujing, Yunnan
    SUN Hao-Ran, GAI Zhi-Kun, CAI Jia-Chen, LI Qiang, ZHU Min, ZHAO Wen-Jin
    2022, 60(3):  169-183.  DOI: 10.19615/j.cnki.2096-9899.220412
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    A new genus and species of the family Eugaleaspidae (Eugaleaspiformes, Galeaspida), Xitunaspis magnus gen. et sp. nov., is described from the Lower Devonian Xitun Formation in Qujing, Yunnan Province, China. The new genus displays the diagnostic characters of the Eugaleaspidae, including a slit-like median dorsal opening, no inner cornual process, developed median dorsal canals, and only three pairs of lateral transverse canals extending from lateral dorsal canals. Different from the other eugaleaspids, X. magnus possesses a large headshield with thick dermal bone and a more plesiomorphic sensory canal system. The phylogenetic analysis of the Galeaspida reveals that Xitunaspis clusters with Dunyu and Eugaleaspis to form a monophyletic clade Eugaleaspidae Liu, 1965, and has a closer relationship with Dunyu than Eugaleaspis by sharing the thick dermal bone of the headshield. The new finding represents the first convincing fossil record of the Eugaleaspiformes in the middle Lochkovian Xitun Formation and adds to our knowledge about the morphology of eugaleaspiforms and the evolutionary pattern of the sensory canal system in the Eugaleaspiformes and even Galeaspida.

    First Middle Devonian galeaspid from the Haikou Formation in Yunnan Province
    MENG Xin-Yuan, Zhu Min, WANG Jun-Qing, PAN Zhao-Hui, GAI Zhi-Kun
    2022, 60(3):  184-196.  DOI: 10.19615/j.cnki.2096-9899.220613
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    The Early Emsian Event (E’Em Event), the most significant bio-event for Chinese Devonian vertebrates, has significantly impacted on the diversity of galeaspids. The endemic Galeaspida almost became extinct after the Mid-Emsian Event (M’Em Event). Only few galeaspid taxa survived from these events, such as Clarorbis apponomedianus from the Eifelian of Guangxi, South China, and an indeterminate galeaspid from the Frasnian of Ningxia, Northwest China. Here, we report the first Middle Devonian galeaspid, Dongfangaspis sp., from the Haikou Formation in Wuding, Yunnan Province. The new material is more suggestive of the type species of Dongfangaspis, D. major, than Laxaspis and Polybranchiaspis in its suborbicular headshield with small inner cornual process, broad and nearly aequilate ventral rim, and about 45 pairs of branchial fossae. Dongfangaspis bears the largest number of branchial fossae ever recorded in galeaspids, which probably play an important role in Dongfangaspis surviving from the E’Em and M’Em events. The new finding represents the second Middle Devonian fossil record of galeaspids, and extends the chronological range of Dongfangaspis from the Pragian (Early Devonian) to the Eifelian (Middle Devonian).

    Reappraisal of the largest ctenochasmatid Moganopterus zhuiana Lü et al., 2012
    GAO Dian-Song, JIANG Shun-Xing, XU Li, CHENG Xin, YANG Li-Li, JIA Song-Hai, WANG Xiao-Lin
    2022, 60(3):  197-211.  DOI: 10.19615/j.cnki.2096-9899.220111
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    Moganopterus zhuiana Lü et al., 2012 was erected as a member of the Boreopteridae, which was questioned by different researchers shortly after the publication. Although the new assignment to the Ctenochasmatidae is widely accepted by pterosaur researchers, some characteristics still require a detailed description. Here, the holotype of this taxon is restudied, and some ambiguous characteristics are re-identified. The diagnosis of this taxon has been revised as the following: a large ctenochasmatid pterosaur, which can be distinguished from other members of this clade by a single autapomorphy: an elongated rod-like parietal crest that extends posterodorsally, forming an angle of about 15° with the ventral margin of the skull. This taxon can be further distinguished from other ctenochasmatids on the basis of the following combination of characteristics: straight occlusal surfaces of the upper and low jaws; presence of a low premaxillary crest confined anterior to the nasoantorbital fenestra; rostrum about two thirds of the skull length; nasoantorbital fenestra occupying slightly more than 20% of the skull length; about 100 slender teeth; and a mid-cervical length/width ratio of about 7. The wingspan of M. zhuiana has been re-estimated according to a simple regression equation for wingspan versus skull length in ctenochasmatids. It confirms that M. zhuiana, although smaller than previous thought, is still the largest known ctenochasmatid. When comparing the sizes of ctenochasmatids in the Jurassic and Cretaceous, ctenochasmatids showed a rough tendency to increase their sizes.

    On kannemeyeriiform dicynodonts from the Shaanbeikannemeyeria Assemblage Zone of the Ordos Basin, China
    LIU Jun
    2022, 60(3):  212-248.  DOI: 10.19615/j.cnki.2096-9899.220601
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    Shaanbeikannemeyeria is a common tetrapod from the lower part of the Ermaying Formation of the Ordos Basin, China. There are taxonomical questions surrounding this genus, such as the validity of the genus, and how many species are included within it. Several specimens have been collected since 1978. Shaanbeikannemeyeria first appeared from the top of the Heshanggou Formation. These specimens are described to clarify the diagnostic characters, the individual variations and the phylogenetic position of Shaanbeikannemeyeria. Only one species, S. xilougouensis, is recognized. It is characterized by the following autapomorphies: occiput strongly inclined relative to the palate such that the skull is much shorter basally than dorsally, sword tip-like premaxillary posterodorsal processes, tall and dorsally-convex cutting blade on the medial edge of the dorsal surface of the dentary, reflected lamina with a separated posteroventral process, and 15 dorsal vertebrae. This species shows variations on the cranial morphology, such as the occiput height relative to the width, the snout tip (sharp or obtuse), the shape of the orbital portion of the zygomatic arch, and the shape of caniniform process. Some variations could be ontogenetically related, such as the development of the caniniform process and tusk, the posterior extension of the maxilla on the zygomatic arch, the distance between the frontal and the premaxilla, the intertemporal bar width, and the exposing degree of the parietals. Based on postcranial bones, the second dicynodont genus (possibly Parakannemeyeria) is present in the lower Ermaying Formation.