Chlupacina sp.

Baliński, Andrzej, 2012, The brachiopod succession through the Silurian-Devonian boundary beds at Dnistrove, Podolia, Ukraine, Acta Palaeontologica Polonica 57 (4), pp. 897-924 : 906

Chlupacina sp.

Fig. 5K, L .

Material.—11 mostly incomplete specimens embedded in rock was found at 5.5 m above the S–D boundary (beds 47–48).

Remarks.—The collection is small and poorly preserved. The specimens show radial ornament which is weak to absent posteriorly and better developed peripherally. The characteristic stronger median costa is usually well developed and reaches the anterior margin. On one specimen a 2.8 mm long (117% of the valve length), proximally cyrtomorph intraverse and distally gently arched spine is well preserved ( Fig. 5L ). Although preservation of spines on the studied specimens is rare, it seems that they are developed on the right side of the ventral valve only.

The present specimens differ from all chonetoid species known from the Siluro–Devonian of Podolia. The former resembles externally Pseudostrophochonetes mediocostalis ( Kozłowski, 1929) from the lower Chortkiv Horizon (former Bogdanovka Beds) in having distinct median costa, but differs mainly in thicker shell ribbing and a much older stratigraphic range. Small shell dimensions, presence of distinct median costa, and long spine developed on one side of the hinge line only suggest that the specimens from the studied section may be Chlupacina . Unfortunately, the paucity of the material and unknown internal shell structure does not allow for a more detailed determination.

Figures

Fig. 5. Strophomenide Plectodonta (Plectodonta) mariae pantherae subsp.nov. (A–J, M–O) and chonetoid Chlupacina sp. (K, L) from the Silurian–Devonian boundary beds at Dnistrove (Podolia, Ukraine). A. Holotype ZPAL Bp. 56/99 in dorsal (A1), ventral (A2), lateral (A3), posterior (A4), and anterior (A5) views, and ventral view of an uncoated shell (A6) to show colour pattern. B. Complete shell ZPAL Bp. 56/108 in dorsal (B1), ventral (B2), lateral (B3), posterior (B4), and anterior (B5) views. C, F, G, I. Four specimens, ZPAL Bp. 56/102 (C), ZPAL Bp. 56/93 (F), ZPAL Bp. 56/103 (G), and ZPAL Bp. 56/104 (I), in ventral exterior view. D. Ventral valve ZPAL Bp. 56/94 in exterior (D1; same as Baliński 2010: fig. 1C2), lateral (D2), and posterior (D3) views. E. Slightly incomplete ventral valve ZPAL Bp. 56/106 in interior view. H, J, N. Three dorsal valves, ZPAL Bp. 56/107 (H), ZPAL Bp. 56/98 (J), and ZPAL Bp. 56/95 (N), in exterior view (N, same as Baliński 2010: fig. 1D2). M. Interior of dorsal valve ZPAL Bp. 56/105 in general (M1) and oblique lateral (M2) views. O. Ventral valve ZPAL Bp. 56/91 in external view showing well preserved ornamentation; two other small shells in dorsal view visible near upper left and lower right corner of the photograph. P. Large ventral valve ZPAL Bp. 56/101 in exterior view. K, L. Chlupacina sp. K. Shell ZPAL Bp. 56/151 in ventral exterior view. L. Slightly damaged shell ZPAL Bp. 56/152 in ventral view. Beds 47–48.