Clorinda pseudolinguifera Kozłowski, 1929

Baliński, Andrzej, 2012, The brachiopod succession through the Silurian-Devonian boundary beds at Dnistrove, Podolia, Ukraine, Acta Palaeontologica Polonica 57 (4), pp. 897-924 : 910-911

Clorinda pseudolinguifera Kozłowski, 1929

Figs. 8 , 9 .

1929 Barrandella (Clorinda) pseudolinguifera sp. n.; Kozłowski 1929: 137, pl. 6: 4–13; fig. 37: IV, fig. 40.

1967 Clorinda pseudolinguifera Kozłowski ; Gratsianova 1967: 63–64; pl. 5: 3; fig. 18.

1985 Clorinda pseudolinguifera Kozłowski, 1929 ; Nikiforova et al. 1985: 33–34; pl. 9: 1, 2. [synonymy therein]

1990 Clorinda pseudolinguifera Kozłowski, 1929 ; Havlíček and Štorch 1990: 121; pl. 33: 8.

Material.—Six complete shells and more than 150 fragmentary valves and shells. Dimensions of the complete shells are given in Fig. 9 . In the studied section the oldest (although fragmentary) specimens were recovered at about 1.0– 1.7 m above the S–D boundary (beds 2, 5, 7, and 9). It becomes quite common at 5.5 m above the boundary (beds 47–48).

Remarks.—Contrary to the majority of species of the studied material from Dnistrove, Clorinda pseudolinguifera is mostly characterised by disjoined valves. This taphonomic characteristic can be explained by different mechanical resistance between cyrtomatodont and deltidiodont hinge teeth. The latter, characteristic for majority of Pentamerida (including Clorinda ), are much more susceptible to mechanical damage and disarticulation.

This species from the Borshchiv Horizon was described in great detail by Kozłowski (1929), including its internal shell structure and the variability of the external morphology, and Podolian material have been considered by Nikiforova (1954), Modzalevskaya (1968), Gauri and Boucot (1968), and Nikiforova et al. (1985). Nikiforova et al. (1985) selected the neotype from the Mitkov beds cropping out at the mouth of Tsyganka stream. The new material contains adult as well as young shells, which illustrate some growth changes in the external morphology of the species ( Figs. 8A–C , 9 ).

Stratigraphic and geographic range.—According to Nikiforova et al. (1985: 33), C. pseudolinguifera occurs through the Khudykivtsy Horizon, becoming common in the lower Mitkov Horizon where it sometimes forms shell banks up to 30–40 mm thick. Conspecific material has been reported from the early Devonian of the Urals ( Gauri and Boucot 1968) and Altai Mountains ( Gratsianova 1967) as well as from the top of Silurian and the lowest Lochkov of Bohemia ( Havlíček and Štorch 1990).

Figures

Fig. 8. Pentameride Clorinda pseudolinguifera Kozłowski, 1929 from the Silurian–Devonian boundary beds at Dnistrove (Podolia, Ukraine). A–C. Three shells, ZPAL Bp. 56/48 (A), ZPAL Bp. 56/49 (B), and ZPAL Bp. 56/50 (C), of different size in dorsal (A1, B1, C1), ventral (A2, B2, C2), lateral (A3, B3, C3), posterior (A4, B4, C4), and anterior (A5, B5, C5) views. D. Exterior view of extensively decorticated ventral valve ZPAL Bp. 56/51 showing cast of the internal morphology of the valve. Beds 47–48. Scale bars 5 mm.

Fig. 9. Scatter diagram of shell width, thickness, and length of tongue to shell length ratios in Clorinda pseudolinguifera Kozłowski, 1929. Dnistrove, beds 47–48.