Eokosovopeltis cf. currajongensis ( Edgecombe and Webby, 2007 )

Lee, Dong-Chan, 2013, Late Ordovician trilobites from the Xiazhen Formation in Zhuzhai, Jiangxi Province, China, Acta Palaeontologica Polonica 58 (4), pp. 855-882 : 864-866

Eokosovopeltis cf. currajongensis ( Edgecombe and Webby, 2007)

Fig. 6H .

Material.—One pygidium from a limestone layer above the mudstone at locality 1 (repository number NIGP−152002).

Remarks.—This pygidium differs from Eokosovopeltis sp. in having much narrower pleural furrows and a narrower (tr.) axial region. It is similar to pygidia of Eokosovopeltis currahttp ://dx.doi.org/10.4202/app.2010.0036

jongensis Edgecombe and Webby (2007: fig. 4C, D, F–I); both have seven pairs of pleural ribs. Due to poor preservation, the specific identification as E. currajongensis is provisional.

Styginidae indet. sp. A

Fig. 6J .

Material.—Two thoraco−pygidia (repository number NIGP−152004).

Remarks.—The sub−circular outline and absence of pygidial pleural furrows resemble Bumastus (see Chatterton and Ludvigsen 1976: pl. 5: 12, 37). However, the presence of distinct ridge along inner margin of marginal border is not present in Bumastus . These specimens may be associated with co−occurring Meitanillaenus ? sp., since they resemble the thoraco−pygidium of Meitanillaenus binodosus Chang (1974 : pl. 81: 6). However, they have much less distinct axial furrows and lack the antero−most pair of pleural furrows.

Styginidae indet. sp. B

Fig. 6I

Material.—Two hypostomes (repository number NIGP−152003).

Remarks.—The hypostomes are of styginid (e.g., see Whittington 1988: fig. 9 for Bumastus ). They are characterized by a more pentagonal outline and a pair of short, closely−spaced spines along posterior margin. The hypostomes may be associated with co−occurring Meitanillaenus ? sp.

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.