Phlogoiderhynchus squamosus ( Wang, 1956 )

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 : 794-795

Phlogoiderhynchus squamosus ( Wang, 1956)

Fig. 4B .

1956 Paurorhyncha squamosa Wang (sp. nov.); Wang 1956: 171–172, pl. 4: D1–D5.

Material.—One almost complete, exfoliated specimen, sample PY3 (see Fig. 2 ).

Discussion.—Major features include: surface with about 35 plications, including 8 on fold; flank plications rarely bifurcating or intercalating; plications low and flat topped, with narrow interspaces; with 0–1 parietal plication; internally, dorsal median septum long, extending to about midlength.

Differences between the studied specimen and the type specimen from the same section are in slightly fewer and coarser plications on the fold. The species is assigned to Phlogoiderhynchus by its external morphology (e.g., large size: 37.4 mm wide, ± 29.4 mm long, and 20.7 mm thick for the figured specimen; wider than long, incurved or adpressed ventral beak, fold and sinus morphology, and biconvex profile). No detailed internal structures are available. It differs from the type species— Phlogoiderhynchus arefactus ( Veevers, 1959a) in its larger size, more convex dorsal valve, and stronger and more numerous flank plications. Calvinaria simplex Chen in Xu et al. (1978) from the Tuqiaozi Formation of the Longmenshan section was assigned to Phlogoiderhynchus by Sartenaer (1985: 314), which is almost smooth, and smaller.

Occurrence.—This species is only found in the Panxi section of eastern Yunnan Province; middle part of the Yidade Formation (Early Frasnian).

Figures

Fig. 4. Strophomenid and rhynchonellid brachiopods from the Early and Middle Frasnian of the Panxi and Caiziyan sections. A. Sulcatostrophia? bunapica Veevers, 1959a, PUM05001, sample PY5, Panxi section, Middle Frasnian, dorsal (A1), ventral (A2), area (A3) views, and enlargement of framed area in image A1 (A4). B. Phlogoiderhynchus squamosus (Wang, 1956), PUM05002, sample PY3, Panxi section, Early Frasnian, dorsal (B1), lateral (B2), and posterior (B3) views. C. Phlogoiderhynchus depressus (Wang, 1956), PUM05003, sample PY2, Panxi section, Early Frasnian, dorsal view. D. Pugnax cf. triplicata (Chen in Xu et al. 1978), PUM05004, sample GC20, Caiziyan section, Early Frasnian, lateral (D1: ventral beak broken), dorsal (D2), and anterior (D3: left anterior broken, right lateral anterior slightly broken) views. E. Coeloterorhynchus sp., PUM05005, sample GC21−24, Caiziyan section, Early Frasnian, dorsal (E1: right anterior and right lateral broken), posterior (E2), and lateral (E3) views.

Fig. 2. Stratigraphy and distribution of Early and Middle Frasnian brachiopods in South China. Most but not all known brachiopods are described and illustrated in this paper. For the distribution of atrypids in the Dushan section, for example, see Ma et al. (2005). The stratigraphy of Panxi and the occurrence of Cyrtospirifer sp. are based on Yunnan compiling group (1978) and the occurrence of Stringocephalus in the lower part of the Yidade Formation is as in Xian et al. (1988: 148). The stratigraphy of Dushan and the occurrence of Stringocephalus sp. are as in Liao et al. (1979); the Caiziyan section was re−measured by Long−Ming Wei, Xue−Ping Ma, and Hua Li (personal communication 2005), with coral identifications by Wei−Hua Liao. The stratigraphy of Qiziqiao is based on data of Z.−X. Hu and Z.−Q. Deng in Tan et al. (1987), and the occurrence of Yunnanella sp. is based on Zu−Han Liu (personal communication 2001). Abbreviations: calc., calcareous; argill., argillaceous; C., Cyrtospirifer; Pa., Palmatolepis; Po., Polygnathus; S., Spinatrypina.