Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 73. (Budapest 1981)

Vörös, A.: A survey of the Rhaetian (Upper Triassic) Bivalvia from Borzavár (Bakony Mts., Hungary)

71861: Avicula gregaria STOPP.

—STOPPANI, Couches à Avicula, p. 70, pl. 11, fig. 6-10. 1870: Mytilus minutus GOLDF.

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FISCHER-OOSTER, Thun, p. 73, pl. II, fig. 31a-b. 71891: Mytilus minutus GOLDFUSS

—SIMONELLI, Cetona, p. 630, pl. I. fig. 5. vl912: Modiola aff. minutae GOLDF. sp. — BITTNER, Lamellibr. Bakonyer Wald., p. 104, pl. VIII, fig. 35. 71929: Modiola gregaria STOPPANI sp.

—DESIO, Albenza, p. 96, pl. I, fig. 6. vl964: Modiola minuta (GOLDFUSS), 1834. — VÉGH, Rhät. Südl. Bakonygeb., p. 36., 74., pl. III., fig. 7 [7], pl. IV., fig. 6. 1967: Modiulus minutus (GOLDFUSS, 1834) — KOCHANOVÁ, Rhaet-Hettang-Grenze, p. 70., pl. III., fig. 1. 71975: Falcimytilus minutus (GOLDFUSS, 1836) — SHOPOV, Hettang. Bulgaria, p. 59., pl. I., fig. 3. Material : 32 partly incomplete specimens. —-Locality : Borzavár, Rhaetian yellow, pink or grey limestones. D i m e n s i o n s (mm): length: 27.0 22.5 21.0 18.5 height: 16.0 13.9 13.4 12.8 Description : The shell is of small size for the genus, strongly inflated, modioliform, almost lanceolate; its obliquity varies between 25° and 30°. The ventral margin bulges strongly at its anterior end, becomes straight or very gently inflected in the middle portion and passes with a gradual curve into the posterior margin. The angle between the posterior and ventral margins is about 25° ; between the posterior and the straight dorsal margins is about 140°. The dorsal (hinge) margin occupies about one-half of the total length of the shell. The umbo is almost terminal. A straight diagonal ridge, which coincides with the maximum convexity of the shell, runs from the umbo to the posteroventral margin. This diagonal ridge is separated from the strongly inflated anteroventral region by a shallow depression. The surface is ornamented with fine, irregularly spaced growthlines. In some cases the median portion of the shell shows feather-like, diverging fibres; this is connected probably with the shell structure. Remarks : Much confusion exists in the literature about the interpretation of this species. There are at least three forms, described by different authors under the names: M. ervensis (STOPPANI, 1857); M. gregarius (STOPPANI, 1860) and M. stoppanii (DUMORTIER, 1864), which are different from M. minutusovXy in unimportant nuances, at least on the basis of the published figures. The study of the original material would be necessary to clear up the picture and perhaps unite these forms into a single species. In the present paper M. gregarius (whose name is preoccupied for a Tertiary form by ZIETEN) is included into the synonymy because the figures of STOPPANI (1. c.) and DESIO (1. c.) show strong similarity to the specimens from Borzavár. The bad figure of SHOPOV (1. c.) does not show any essential features but the fact that he placed his specimens into the very peculiar genus Falcimytilus Cox contradicts the specific assignement. Distribut ion: Rhaetian of South Germany, the "Préalpes", the Southern Alps, the NW Carpathians and the Bakony Mts (Hungary); Hettangian of South Germany and Bulgaria(?) Modiolus (Modiolus) faba (WINKLER, 1859) (Plate I: 5-6, 7a-b) * 1859: Myacitesfaba WINKLER, Schichten der Avicula, p. 19, pl. II, fig. 6a-b. 1861: Lithophagus ? faba WINK.

—STOPPANI, Couches à Avicula..., p. 67, pi. 10, fig. 12-14. 1919: Modiola Visgnolae, nov. sp. — MARIANI, Fauna retica Lomb., p. 123, pl. VII. fig. 8. 1929: Modiola Adrarae ANELLL—DESIO, Albenza, p. 98, pl. I, fig. 3. 71929: Modiola orbicularis sp. n. — Ibid., p. 98, pl. I, fig. 1-2. 1930: Modiola (non Myacites, non Lithodomus) faba WINKL.

—OSSWALD, Risserkogelgebiet, p. 742, pi. 53, fig. 14. vl964: Modiola faba (WINKLER), 1859. — VÉGH, Rhät. Südl. Bakonygeb., p. 36, 73, pl. III. fig. 4-6. non 1866: Myacites faba, WINK.

—CAPELLINI, Infralias. Spezia, p. 47, pl. Ill, fig. 13.