Pyramidaspirifer Ma and Day, 2000

Ma, Xue-Ping, Becker, Ralph Thomas, Li, Hua & Sun, Yuan-Yuan, 2006, Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf, Acta Palaeontologica Polonica 51 (4), pp. 789-812 : 806-807

Genus Pyramidaspirifer Ma and Day, 2000 Pyramidaspirifer cf. helenae ( Fenton, 1918)

Fig. 11H .

1918 cf. Spirifer cyrtinaformis helenae nov. var.; Fenton 1918: 216, pl. 6: 11–17.

1982 cf. Tenticospirifer cf. T. cyrtinaformis ( Hall and Whitfield, 1872) ; Cooper and Dutro 1982: 112, pl. 33: 9–15.

Material.—One poorly preserved, distorted specimen (sample QZQ4) from the basal part of the Qilijiang Formation in the Qiziqiao section.

Description.—Flank plications simple, with about 17 on each flank, diminishing in strength laterally; sinal plications also simple, except for the central one, which bifurcates and is slightly weaker, totally 8 in number anteriorly; sinus shallow but distinct, originating near posterior end, without primary plications; fold only appearing at mid−length, with weaker plications centrally, transitions between fold and flanks gradual, without a distinct delimiting furrow on each side. Discussion.—The nature of the fold and sinus (no primary plications in the sinus and no delimiting furrow on each side of fold) excludes it from the Cyrtospiriferidae (e.g., Tenticospirifer ). The shell is similar to North American Late Frasnian Pyramidaspirifer helenae ( Fenton, 1918) except that the Qiziqiao specimen has a more swollen ventral valve.

MA ET AL.—FRASNIAN BRACHIOPODS FROM SOUTH CHINA SHELF 807

5 mm

Pyramidaspirifer has only been recognized in the Late Frasnian of North America, and this extends its geographic distribution to South China.

Occurrence.—The present species occurs in Bed 20 of the Qiziqiao section of central Hunan, correlated with the lower part of the Early Palmatolepis rhenana Zone.

Figures

Fig. 11. Plicate spiriferid brachiopods from the Frasnian of the Qiziqiao and Qifengzhen sections. A. Theodossia? sp. PUM05027, sample QZQ4, Qiziqiao section, probably early Late Frasnian (cardinal extremities somewhat broken), ventral (A1), area (A2), and lateral (A3) views of a ventral valve. B–D. Cyrtospirifer? sp. B. PUM05028, sample QZQ3, Qiziqiao section, Middle Frasnian, dorsal (B1), posterior (B2), ventral (B3), lateral (B4), and anterior (B5) views of a juvenile.C. PUM05029, sample QZQ1, Qiziqiao section, Middle Frasnian, posterior (C1), lateral (C2), anterior (C3), dorsal (C4), and ventral (C5) views, note the thick shell material. D. PUM05030, sample QZQ1–3, Qiziqiao section, Middle Frasnian, ventral interior (D1), lateral (D2), and ventral exterior (D3) views, note thickened ventral posterior. E, F. Cyrtospirifer cf. sichuanensis Chen in Xu et al. (1978). E. PUM05031, dorsal view of a heavily exfoliated specimen of sample GQ6 of the Qifengzhen section in the vicinity of Guilin, about 17 m above the base of the “Gubi Formation” (Zhong et al. 1992). F. PUM05032, sample QZQ1, Qiziqiao section, Middle Frasnian, ventral view of an entirely exfoliated specimen. G. Cyrtospirifer cf. extensa Ching et Liu in Wang et al. 1982; PUM05033, sample QZQ1, Qiziqiao section, Middle Frasnian (cardinal extremities somewhat broken), anterior (G1), dorsal (G2), ventral (G3), lateral (G4), and posterior (G5) views. H. Pyramidaspirifer cf. helenae (Fenton, 1918); PUM05034, sample QZQ4, Qiziqiao section, probably early Late Frasnian, dorsal (H1), ventral (H2), lateral (H3), area (H4), and anterior (H5) views of a slightly distorted shell.