Schizophoria 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 : 521

Schizophoria sp.

Fig. 27A–E .

Material.—30 fragmentary single valves.

Remarks.— Although the described material is fragmentary it likely represents the genus Schizophoria based on the characteristic ventral muscle platform. This form, however, cannot be assigned to the species described above because it is distinguished by having a clearly parvicostellate shell ornamentation. There are usually about 8–9 stronger costae which appear near the beak and continue to the anterior margin of valves. Some additional stronger costellae may appear later during growth. At 5 mm from beak there are 4–8 weaker costellae between each pair of stronger ones. Aditicules are very rare or not observed. Valves are thin−shelled and densely punctate. In lateral profile the ventral valves are weakly convex posteriorly but concave in the middle region. Most probably this form represents a new species but it is not possible to define it more precisely due to insufficient material.

Stratigraphic and geographic range.—This species occurs in sample GB, MH1, and D2.

Figures

Fig. 27. Schizophoriid brachiopods from the Muhua Formation, sample MH1. A–E. Schizophoria sp. A, B. Incomplete ventral valves, PKUM02−0345 (A) and PKUM02−0346 (B), in exterior (A1, B1) and interior (A2, B2) views. C. Incomplete ventral valve, PKUM02−0347, in exterior view. D. Incomplete ventral valve, PKUM02−0349, in interior view. E. Ventral valve, PKUM02−0348, in exterior view. F–L. Schizophoria (Schizophoria) resupinata (Martin, 1809). F. Ventral valve, PKUM02−0350, in exterior view. G, H. Dorsal valves, PKUM02−0351 (G) and PKUM02−0352 (H), in exterior (G1, H1) and interior (G2, H2) views. I. Ventral valve, PKUM02−0353, in interior view. J. SEM micrograph of juvenile shell, PKUM02−0354, in dorsal (J1) and posterior (J2) views. K. SEM micrographs of incomplete valve, PKUM02−0355, showing external costellae, nearly filled with shell substance openings of aditicules, and shell punctation; specimen in general (K1) and enlarged (K2) views. L. SEM micrograph, PKUM02−0356, showing external ornamentation, large openings of aditicules, and shell punctation.