Draborthis cf. caelebs Marek and Havlíček, 1967

Hints, Linda & Harper, David A. T., 2015, The Hirnantian (Late Ordovician) brachiopod fauna of the East Baltic: Taxonomy of the key species, Acta Palaeontologica Polonica 60 (2), pp. 395-420 : 413

Draborthis cf. caelebs Marek and Havlíček, 1967

Fig. 11C, E, F .

Material.— Six specimens embedded in rock. Porkuni Regional Stage , Kuldiga Formation , Hirnantian ( Upper Ordovician ); western Latvia. Drill core and depth (in meters) of brachiopod samples. Collection GIT 542 : Engure, 884.3; Mežmaļi-16, 913.2; Riekstinis-15, 857.5–858.6 .

Remarks.—Small, weakly sulcate suboval to subquadrate dorsal valves with the valve width 7.1 mm and length 4.8 mm. Brachiophores widely divergent ( Fig. 11C, F ), cardinal process with small nodule-like myophore on the floor of notothyrial cavity, narrow septum reaches the anterior half of the valve. Although the Baltic valves are small, in comparison with D. caelebs from Sweden ( Bergström 1968) and Bohemia ( Marek and Havlíček 1967), they are based on dorsal internal characters clearly related to that species and distinguish it from other small dalmanellidine brachiopods in the Baltic area.

Figures

Fig. 11. Dalmanellid brachiopods from the Kuldiga Formation of the Porkuni Regional Stage, Hirnantian (Upper Ordovician), East Baltic, western Latvia A–D, F–I) and southwestern Estonia (E). A, B, D, H, I. Onniella sp. A. Dorsal valve, GIT 542-66, Aispute-41, depth 1001.15 m, exterior view. B. Ventral valve, LDM 382-50, Dižrungi-17, 896.0 m, ventral view. D. Shell, GIT 542-471, Riekstini-15, 860.85, dorsal (D 1), ventral (D 2), and lateral (D 3) views. H. Dorsal valve, GIT 542-480, Krjukai, 968.6 m, dorsal exterior view. I. Shell, GIT 542-472, Kandava-26, 964.5 m, ventral (I 1) and dorsal (I 2) views. C, E, F. Draborthis cf. caelebs Marek and Havliček, 1967. C. Dorsal valve, GIT 542-392, Riekstini-15, 857.5, interior view. E. Dorsal valve, GIT 542- 67, Ruhnu-500, 914.0 m, exterior view. F. Dorsal valve, GIT 542-4393, Mežmali-16, 913.2 m, interior view.G. Drabovia sp., dorsal valve, GIT 542-473, Mežmali-16, 910.1 m, interior view. Scale bars 2 mm.