Niutoushania Liao, 1984

Chen, Zhong-Qiang, Campi, Monica J., Shi, Guang R. & Kaiho, Kunio, 2005, Post-extinction brachiopod faunas from the Late Permian Wuchiapingian coal series of South China, Acta Palaeontologica Polonica 50 (2), pp. 343-363 : 355

Genus Niutoushania Liao, 1984

Type species: Niutoushania niutoushanensis Liao, 1984 ; Wuchiapingian (Late Permian), Anhui, South China .

Emended diagnosis.—Medium to large, suboval to subquadrate shell, geniculate anteriorly; corpus cavity moderately deep; sulcus and fold indistinct; fine spines on dense ventral ribs; rugae absent or weakly developed on umbo. Ventral interior adductor scars elongate, ridge−shaped; diductor scars broad, flabellate, deeply grooved ( Fig. 12A ). Cardinal process bilobate, supported by a thin median septum; cardinal ridges extending along hinge margins; anterior adductor scars elongate, highly raised, tear−shaped; posterior adductor scars strongly dendritic; brachial ridges hook−shaped, nearly horizontally given off; inner surfaces strongly tuberculate ( Fig. 12B ). The redefined Niutoushania shares similar size, shell outline and general ornamentation with both Tyloplecta Muir−Wood and Cooper, 1960 and Tarimoplecta Chen and Shi, 2000 , but it differs clearly from the latter two in lacking a much deeper corpus cavity and fine capillae, which are diagnostic of both Tyloplecta and Tarimoplecta (Chen and Shi 2000; Shi and Chen 2003). Moreover, the conspicuous nodes characterize the ventral umbo of Tyloplecta , and the costae of Tarimoplecta broaden abruptly at the start of the geniculation. None of these characteristics is present in Niutoushania .

Remarks.—Generic diagnosis is emended here based on re−examining the type specimens of the type species housed in Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences. These type specimens, like the Daijiagou materials, were also collected from the Lungtan coal series in Changxing, South China; both bear some similarities. However, our new materials provide more detailed ventral internal features. Niutoushania can be separated from other dictyoclostines by its indistinct reticulations, a lower, thinner dorsal median septum, and more pronounced brachial scars, which are perpendicular to the median septum.

Figures

Fig. 12. Interiors of Niutoushania chongqingensis Chen sp. nov. (based on specimen NMV P309641); ventral valve (A) and dorsal valve (B).