Cymostrophia (Protocymostrophia) costatula ( Barrande, 1847 )

Baliński, Andrzej, 2012, The brachiopod succession through the Silurian-Devonian boundary beds at Dnistrove, Podolia, Ukraine, Acta Palaeontologica Polonica 57 (4), pp. 897-924 : 904

Cymostrophia (Protocymostrophia) costatula ( Barrande, 1847)

Fig. 4K, N–P .

1847 Leptaena costatula Barrande ; Barrande 1847: 65, pl. 21: 17.

1929 Stropheodonta (Brachyprion) cf. costatula (Barrande) ; Kozłowski 1929: 100, pl. 3: 33.

1967 Mesodouvillina costatula (Barrande, 1848) ; Havlíček 1967: 170– 171, pl. 34: 7, 9–12; fig. 69.

1968 Mesodouvillina costatula (Barrande) ; Modzalevskaya 1968: pl. 27: 2, 3.

1985 Mesodouvillina costatula (Barrande) ; Nikiforova et al. 1985: 22.

Material.— 47 specimens, mostly fragmentary, embedded in rock. The species occurs scarcely at 1.5 m (bed 7) above the S–D boundary, but becomes much more common at 5.5 m (beds 47–48) above the S–D boundary.

Remarks.—Specimens from the studied interval at Dnistrove appear to be conspecific with Stropheodonta (Brachyprion) cf. costatula from the Khudykivtsi Beds of Myszkowce as illustrated by Kozłowski (1929: pl. 3: 33). More recently, Podolian collections from the same stratigraphic interval were attributed to Mesodouvillina costatula ( Modzalevskaya 1968; Nikiforova et al. 1985). The latter authors discussed the relationship of the Podolian material with the type specimens of C. (P.) costalula from the lower Devonian of Bohemia, as well as with C. (P.) costatuloides ( Johnson, Boucot, and Murphy, 1973) from the Pridoli of Nevada. According to Nikiforova et al. (1985), the specimens described by Nikiforova (1954) from the Malinovtsy and Skala horizons are probably more closely related to C. (P.) costatuloides , whereas specimens from the Khudykivtsi Beds are conspecific with C. (P.) costatula . This may also apply to two specimens reported (but not illustrated) by Kozłowski (1929) from the Dzwinogorod Beds of the Skala Horizon.

Stratigraphic and geographic range.—The species was originally described from the Kotýs limestone (Lochkov, Lower Devonian) of Bohemia ( Barrande 1847; Havlíček 1967). Recently Iordan (1999) found the species in the Silurian (Wenlock) of the Bătrânesti borehole, Romania. Similar form is listed as Mesodouvillina aff. costatula by Berdan et al. (1969) from the upper Silurian of Nevada. In Podolia the species occurs in the Khudykivtsi Beds of the Borshchiv Horizon.

Figures

Fig. 4. Strophomenide brachiopods from the Silurian–Devonian boundary beds at Dnistrove (Podolia, Ukraine). A–J, L. Leptaena (Leptaena) aff. altera Rybnikova, 1966. A, B. Two nearly complete shells, ZPAL Bp. 56/42 (A) and ZPAL Bp. 56/43 (B), in dorsal (A1, B1), ventral (A2, B2), lateral (A3, B3), posterior (A4, B4), and anterior (A5, B5) views. C. Shell ZPAL Bp. 56/46 in ventral view (C1) and enlargement showing the pedicle tube (C2). D. Enlargement of the posterior region of the ventral valve ZPAL Bp. 56/32d showing interarea, delthyrium, and well preserved teeth. E–G. Enlargement of the posterior region of three shells, ZPAL Bp. 56/32c (E), ZPAL Bp. 56/32b (F), and ZPAL Bp. 56/32a (G); ventral valves uppermost. H. Almost complete shell ZPAL Bp. 56/45 in ventral view. I. Enlargement of the interior of ventral valve ZPAL Bp. 56/32e. J. Ventral valve ZPAL Bp. 56/44 with partially shown interior in general (J1) and enlarged (J2) views. L. Interior of incomplete dorsal valve ZPAL Bp. 56/32f. K, N–O. Cymostrophia (Protocymostrophia) costatula (Barrande, 1847). K. Incomplete shell ZPAL Bp. 56/18 in dorsal (A1) and ventral (A2) views. N. Interior of dorsal valve ZPAL Bp. 56/21. O. Interior of an incomplete ventral valve ZPAL Bp. 56/19. P. Exterior of an incomplete ventral valve ZPAL Bp. 56/20. M.?Mesodouvillina sp.; exterior of ventral valve ZPAL Bp. 56/53. Beds 47–48 (A–L, N–P), 102 (M). Scale bars 2 mm.