Squamulariina, Frederiks, 1916

Baliński, Andrzej, 2006, Brachiopods and their response to the Early-Middle Frasnian biogeochemical perturbations on the South Polish carbonate shelf, Acta Palaeontologica Polonica 51 (4), pp. 647-678 : 674

Squamulariina ? sp.

Fig. 20E .

Material.—One slightly damaged ventral valve from Wietrznia Id−W section (bed 4g).

Remarks.—A single ventral valve is referred to the genus on the basis of its hemipyramidal shape, smooth external surface, very high and flat interarea, presence of trichorinum in the apical part of the delthyrium and punctate shell substance. The valve is widest along hinge line where it attains 7.4 mm; interarea is 5.9 mm high. Flanks of the valve are almost flat and triangular, sulcus is shallow and quite narrow. The specimen differs from the type species of the genus Squamulariina parva ( Gürich, 1896) described from the Middle Devonian of the Holy Cross Mountains, by having much wider and flat, not concave interarea.

Occurrence.—The genus Squamulariina is known from the Middle Devonian of Europe, Russia, and China ( Gürich 1896; Biernat 1966; Ivanova 1962; Zhang 1989). In Poland it was recovered from the Late Eifelian–Early Givetian strata of Łysogóry region ( Halamski 2004). A single specimen described here was found in Palmatolepis transitans Zone and may thus represent the youngest occurrence of the genus. However, better collection is needed to acknowledge the upper (Early Frasnian) range of Squamulariina .

Figures

Fig. 20. Spiriferid and spiriferinid brachiopods from the Frasnian of Wietrznia and Dębnik. A. Emanuella sp., ZPAL Bp 60/20, damaged shell from the middle Wietrznia Beds of Wietrznia Ie in dorsal (A1), ventral (A2), lateral (A3), posterior (A4), and anterior (A5) views. B. Eleutherokomma zarecznyi (Gürich, 1903), ZPAL Bp 60/9, incomplete shell from the Nodular Limestone (Pa. hassi Zone) of Dębnik in dorsal (B1), ventral (B2), lateral (B3), posterior (B4), and anterior (B5) views. C, D. Tenticospirifer? sp. from the middle Wietrznia Beds of Wietrznia Ie. C. Damaged ventral valve ZPAL Bp 60/24 in ventral (C1) and posterior (C2) views. D. Exterior of incomplete dorsal valve ZPAL Bp 60/25. E. Squamulariina? sp., GIUS 4−273 Wt/IM−6, ventral valve from the middle Wietrznia Beds of Wietrznia Id−W in posterior (E1) and ventral (E2) views. F, G. Cyrtospirifer bisellatus (Gürich, 1903) from the Nodular Limestone (Palmatolepis hassi Zone) of Dębnik. F. Shell ZPAL Bp 60/14 in dorsal (F1), ventral (F2), lateral (F3), posterior (F4), and anterior (F5) views. G. Exterior of large ventral valve ZPAL Bp 60/22.