Rugosochonetes sp.

Sun, Yuanlin & Baliński, Andrzej, 2008, Silicified Mississippian brachiopods from Muhua, southern China: Lingulids, craniids, strophomenids, productids, orthotetids, and orthids, Acta Palaeontologica Polonica 53 (3), pp. 485-524 : 504-506

Rugosochonetes sp.

Fig. 13A, C, D.

Material.—One complete dorsal valve.

Remarks.—This single dorsal valve from sample M2−8 ( Fig. 13A) is 7.4 mm wide and 5 mm long with subquadrate outline. It is flat to slightly concave anteriorly, and covered with radial capillae. There are 6 capillae per mm at 3 mm distance from dorsal beak. Internally the inner socket ridges are relatively short, anteriorly divergent from the hinge line at angle about 30 °. Anderidia divergent anteriorly at about 65 °. A rudimentary median septum can be seen slightly anterior to the anderidia. Prominent endospines are concentrated on the anterior median portion. It differs from R. cf. celticus described above in having a dorsal valve with flat lateral profile, a slightly finer radial ornament, more anteriorly directed inner socket ridges, more posteriorly located rudimentary median septum, and more strongly developed endospines.

A few incomplete specimens found in sample MH1 also represent Rugosochonetes (see Fig. 13C, D) but differ from R. cf. celticus described above in having slightly finer radial capillae.

Stratigraphic and geographic range.—The single specimen referred here to the genus Rugosochonetes was recovered from M2−8, about 3.5 m above base of the Muhua Formation. Another form representing the genus was found in sample MH1.