Eokosovopeltis sp.

Lee, Dong-Chan, 2013, Late Ordovician trilobites from the Xiazhen Formation in Zhuzhai, Jiangxi Province, China, Acta Palaeontologica Polonica 58 (4), pp. 855-882 : 864

Eokosovopeltis sp.

Fig. 6G .

Material.—One pygidium (repository number NIGP−152001).

Remarks.—This pygidium bears morphologic features of Eokosovopeltis . Compared with pygidia of other Late Ordovician Eokosovopeltis species such as E. romanovskii (= Bronteus romanovskii ) ( Weber 1948: pl. 7: 20–23), E. atavus (= Heptabronteus atavus ) ( Webby 1974: pl. 28: 15–18), E. grandicurvatus ( Edgecombe et al. 2004: fig. 5A–F), E. currajongensis ( Edgecombe and Webby 2007: fig. 4C, D, F–I), the pygidium differs in having an inverted trapezoidal axis with a pair of longitudinal furrows, concave anterior part of the postaxial region, and slightly convex posterior part of the postaxial region with faintly impressed longitudinal furrow. Of the species, the pygidial morphology of E. currajongensis is most similar to this pygidium, but the former differs in having a sagittally much wider articulating half ring, faintly−defined anterior limit of postaxial region, and obliquely−directed anterior margin. To confidently erect a new Eokosovopeltis species to which this pygidium is assigned requires discovery of cranidial materials.

This pygidium might be associated with the styginid cranidia assigned to Meitanillaenus ? sp. ( Fig. 6A–E ). However, the pygidium occurs in locality 2, whereas the cranidia occur in locality 3. Since the mudstone of each locality is not stratigraphically contemporaneous (see above), the association is considered less likely.

Figures

Fig. 6. Late Ordovician trilobites from Xiazhen Formation near Zhuzhai, Yushan County, China. A–E. Meitanillaenus? sp. A. NIGP−151995, cranidium from locality 3; dorsal (A1) and anterior (A2) views. B. NIGP−151996, cranidium from locality 3; dorsal (B1) and lateral (B2) views. C. NIGP−151997, cranidium from locality 3, dorsal view. D. NIGP−151998, cranidium from locality 3, dorsal view. E. NIGP−151999, cranidium from locality 3, dorsal view. F. Amphilichas sp., NIGP−152000, cranidium from locality 3; dorsal (F1), oblique posterior (F2), anterior (F3), and lateral (F4) views. G. Eokosovopeltis sp., NIGP−152001, pygidium from locality 2, dorsal view. H. Eokosovopeltis cf. currajongensis (Edgecombe and Webby, 2007), NIGP− 152002, pygidium from a limestone layer overlying the mudstone at locality 1, dorsal view. I. Styginidae indet. sp. B, NIGP−152003, hypostome from locality 3, ventral view. J. Styginidae indet. sp. A, NIGP−152004, incomplete thoraco−pygidium with four thoracic segments from locality 3, dorsal view. K, M. Asaphidae indet. K. NIGP−152005, free cheek from locality 2, dorsal view. M. NIGP−152006, pygidium from locality 3, dorsal view. L. Nileus sp., NIGP−152007, articulated specimen minus free cheeks from locality 2; posterior (L1), anterior (L2), lateral (L3), and dorsal (L4) views. Scale bars 2.5 mm, except E, F, I 1 mm; G, H, K 5 mm.