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)
Material : 4 specimens (an almost complete and 3 fragmentary shells). — Locality: Borzavár, Rhaetian yellow and grey limestones. Dimensions (mm): length: 12.0 — 7.8 height: 10.7 10.5 7.6 Description : The small shell is almost flat, only the umbonal part is gently inflated. The outline is subcircular. The umbo is not prominent, lies on or little below the dorsal margin. The growth rugae are irregular in strength and distribution ; radial capillation is barely visible. Some specimens show allomorphic sculpture in the form of irregular pits and swellings. Remarks: P. schafhaeutli was included by DITTMAR (1864, p. 156) into P. alpina as a juvenile form of the latter; this opinion is accepted here. Desio (1929, p.87.) tried to separate the two forms on the basis of their length/height ratio, however, this does not seem to be reasonable since: (1) the outline is very variable in all Placunopsis; (2) WINKLER (1959, p.5.) wrote about the original specimens of his P. alpina: „Die Objekte sind alle so ... eingewachsen, dass es schwierig ist, die wahre Form des Umrisses der einzelnen zu erkennen, ... ". According to DESIO (1929, p.87.) P. favrii is conspecific with P. alpina and this view is supported by the figure 14. in CAPELLINI (I.e.). The specimen figured on pl.36., fig.ll. by STOPPANI (I.e.) as Anomia revonii, seems to be a typical P. alpina. P. mort illeti (STOPPANI, 1863) differs from P. alpina by its more regularly spaced growth rugae and stronger radial riblets. Distribution : Rhaetian of England, the Northern and Southern Alps, the Northern Apennines, the Western Carpathians and the Bakony Mts. (Hungary). Genus LIMATULA WOOD, 1839 Limatula alpissordidae (WINKLER, 1864) (Plate II: 6) *1864: Lima alpis sordidae WINKLER, Beitr. Geol. bayer. Alpen, p. 299, pl. VI. fig. 5. 1917: Lima (?Ctenostreon) alpis sordidae WINKL. —GOETEL, Rhät. Stufe Tatra, p. 137, pl. VIII, fig. 8a-b. 1963: Lima (Ctenostreon? ) alpis sordidae WINKLER — ZAPFE, Nordalpinen Riffe, Adnet, p. 234, pl. 2, fig. 5-6. Material : 13 specimens (incomplete shells and internal casts). — Locality : Borzavár, Rhaetian grey limestones. Dimensions (mm): length: 16.0 15.5 15.0 12.5 10.7 height: 27.8 26.0 27.0 21.5 15.3 Description : The shell is of medium size for the genus; moderately inflated. The outline is high oval, slightly inequilateral. The anterior margin is nearly straight, the posterior one is moderately convex; they form an even curve with the ventral margin. The auricles are not well seen but they seem to be equal and small. A blunt diagonal ridge runs from the umbo to the anteroventral margin with steeper anterior flank. The shell is ornamented with 14 sharp radial ribs ; their interspaces are U-shaped in cross-section. A few, stronger growth lines gently break the course of the ribs. Remarks : WINKLER (I.e.) figured an incomplete specimen, but GOETEL (I.e.) and ZAPFE (I.e.) gave nice figures and exhaustive description of L. alpissordidae. The outline and ornamentation of this species seem to be more similar to the genus Limatula than to Ctenostreon, namely, the latter is suborbicular and has a very thick shell with scaly or spinose ribs. Distribution : Rhaetian of the Northern Limestone Alps, the Western Carpathians and the Bakony Mts. (Hungary).
