Homoeorhynchia cf. maninensis (Siblík, 1967)

Vörös, A., 2014, Early Jurassic brachiopods from diverse localities of northern Anatolia (Turkey), Fragmenta Palaeontologica Hungarica 31, pp. 7-49 : 23-24

Homoeorhynchia cf. maninensis (Siblík, 1967)

(Figs 30–32)

* 1967 b Slovenirhynchia maninensis sp. n. – SIBLÍK, Domerian, p. 161, text-figs 4–9, pl. X, figs 1–4, pl. XI, figs 1–3.

1967 b Slovenirhynchia slovenica sp. n. – SIBLÍK, Domerian, p. 165, text-figs 10–12, pl. XII, figs 2–4.

? 1989 Homoeorhynchia almaensis ( Moisseiev, 1934) – TCHOUMATCHENCO, Kotel I, p. 18 (pars), pl. II, figs 1–5 (non figs 6–9).

Material – One slightly damaged specimen from Beytepe (Ankara area), probably Pliensbachian.

Measurements –

L W T Ch INV 2014.100. 13.1 15.4 8.1 7.9

Remarks – Our specimen has laterally expanded subquadrangular outline, weak deflections on its lateral commissures and biplicate anterior margin with two, sharp, equidimensional (i.e. perfectly symmetrical) deflections. The characters of its beak also support its attribution to the genus Homoeorhynchia .

The Turkish specimen is extremely similar to those figured by SIBLÍK (1967 b) on pl. X, fig. 1, as Slovenirhynchia maninensis and on pl. XII, fig. 3, as S. slovenica (the junior synonym of maninensis ), therefore it was identified as maninensis . Siblík’s genus Slovenirhynchia was taken as synonymous with Homoeorhynchia ( SUČIĆ-PROTIĆ 1969; AGER 1983). This was also accepted by SIBLÍK (1999, and pers. comm.), who considered maninensis as a representative of a morphological group within Homoeorhynchia , which was characterized by less cynocephalous (i.e. somewhat depressed) shape and symmetrically developed biplication. This “ maninensis -group” differs from the examples mentioned by AGER (1983) in the “marginal populations” of H. acuta (J. Sowerby, 1816) , bearing two or three sharp deflexions in their anterior commissures. These specimens of the marginal population have always asymmetrically developed secondary riblets or weak deflexions on the sides of the high uniplication, as illustrated by MOISSEIEV (1934, pl. V, figs 10, 11), AGER (1959 a, text-fig. 1) and VÖRÖS (2014, pl. I, figs 7, 8) from Yakacik ( Turkey) and VÖRÖS (2009, pl. IX, fig. 5) from Hungary.

Some other species, as possible members of the “ maninensis -group”, e.g. H. steinmanni (Haas & Petri, 1882) and H. solitaria Siblík, 1999 were mentioned by SIBLÍK (1999), who discussed the differences between them as well. Further relat- ed forms were illustrated by SUČIĆ-PROTIĆ (1969) under the name Planirhynchia tantilla sp. nov. and by TCHOUMATCHENCO (1989) as Homoeorhynchia almaensis ( Moisseiev, 1934) . Especially some specimens figured by TCHOUMATCHENCO (1989, pl. II, figs 1–5) seem very similar to H. maninensis by their highly and sharply biplicate anterior commissure. It has to be mentioned, that the original specimen of „ Rhynchonella ” almaensis figured by MOISSEIEV (1934, pl. III, figs 51–54) is not biplicate, but shows three zig-zag deflections of different altitude. H. maninensis was recorded from the Upper Pliensbachian of the West Carpathians and the Balkans (Kotel) and now from northern Anatolia.