Verneuiliidae Schuchert, 1929

Sun, Yuanlin, Baliński, Andrzej, Ma, Xueping & Zhang, Yubo, 2004, New bizarre micro-spiriferid brachiopod from the Early Carboniferous of China, Acta Palaeontologica Polonica 49 (2), pp. 267-274 : 269

Family Verneuiliidae Schuchert, 1929

[nom. transl. Brunton, 1984: 101 (ex Verneuiliinae Schuchert, in Schuchert and LeVene, 1929: 21)]

Type genus: Verneuilia Hall and Clarke, 1893 .

Emended diagnosis.—Transverse to subcircular, biconvex, with opposed folding forming lobate to metacarinate anterior margins; ventral interarea narrow to full width of valves, apsacline to procline, with open delthyrium or restricted by the apical pseudodeltidium; hinge line commonly denticulate; growth lines without capillae; dental plates or dental adminicula absent.

Discussion.—Four genera are assigned to this family: Verneuilia Hall and Clarke, 1893 , Minythyra Brunton, 1984 , Nuguschella Tjazheva, 1960 , and the new genus Changshunella described herein. Previously, some researchers placed verneuiliids under a different family or superfamilies, such as Cyrtinidae Frederiks, 1911 ( Wang et al. 1966: 590; Zhang et al. 1983: 374), Reticulariacea Waagen, 1883 ( Brunton 1984), Ambocoelioidea George, 1931 ( Blodgett and Johnson 1994; Carter et al. 1994), and Spiriferacea ? King, 1846 ( Gourvennec 1994).

Although some members of the verneuiliids possess a cyrtiniform shell reminiscent of the Cyrtinidae , none of the verneuiliids is known with a punctate shell structure. According to Carter et al. (1994), the impunctate and punctate spiriferid brachiopods are placed in different orders. The presence of a denticulate hinge line in both Verneuilia ( Brunton 1984; Gourvennec 1994) and the new genus Changshunella strongly suggests that the verneuiliids neither belong to the Reticulariacea nor Ambocoelioidea ; they may have close affinity with spiriferids having a denticulate hinge line. According to the recently revised classification of the spiriferid brachiopods ( Carter et al. 1994), all denticulate spiriferids are grouped into the three superfamilies, Spiriferoidea King, 1846, Paeckelmanelloidea Ivanova, 1972, and Brachythyridoidea Frederiks, 1924. Gourvennec (1994) considered assigning Verneuiliidae to the superfamily Spiriferacea (= Spiriferoidea proposed in Carter et al. 1994), however, the lack of dental plates or dental adminicula in verneuiliids does not support this viewpoint, although the condition exceptionally can also be observed in spiriferoids. Internally the verneuiliids might fit into the Brachythyridoidea but the latter generally have a narrow hinge line and rounded cardinal extremities. Furthermore, none of spiriferoids, paeckelmanelloids or brachythyridoids is known to have opposite folding. In the current paper we maintain verneuiliids as a separate family of the suborder Spiriferidina and are reluctant to assign them to any of the three superfamilies characterized by denticulation unless they are regrouped in one superfamily. Alternatively, verneuiliids could have their own superfamily, namely Verneuilioidea, derived from an offshoot of the same stock that produced the superfamilies of Spiriferoidea, Paeckelmanelloidea and Brachythyridoidea by developing opposite folding and loss of dental plates or dental adminicula.