Eryma australe ( Secrétan, 1964 ), Tithonian

Charbonnier, Sylvain, Garassino, Alessandro & Pasini, Giovanni, 2012, Revision of Mesozoic decapod crustaceans from Madagascar, Geodiversitas 34 (2), pp. 313-357 : 313-357

? Eryma australe ( Secrétan, 1964) ( Fig. 11 )

Erymastacus australis Secrétan, 1964: 72-74 , pl. 1, fig. 2; pl. 2, figs 1-5.

Eryma australe – Schweitzer et al. 2010: 23.

HOLOTYPE. — MNHN.F. R 03972.

PARATYPES. — From Northern Analavelona Massif (Tulear Province): 2 specimens ( MNHN.F. R 03971, A31660, hillock southwest of Ankilivalo, gisement 1153) ; 1 specimen ( MNHN.F.A33207, gisement 1205, Marolalitra River , Befandriana south). High Sikily region , northern Analavelona Massif , Tulear Province , southern Morondava Basin, Tulear Province .

TYPE LOCALITY. — Northern Analavelona Massif (Tulear Province), southwest Ankilivalo (gisement 1153), Tulear Province.

TYPE AGE. — Early Tithonian ( Hildoglochiceras kobelli zone).

DISCUSSION

The type material comprises merely poorly preserved, fragmentary chelipeds and does not permit a detailed characterization of this species. The features that are recognizable include: very large and compressed propodus, with inner margin strongly tuberculate, outer margin smooth; index and dactylus curved; elongate and narrow index: outer margin smooth, occlusal margin with a single row of small, rounded teeth; dactylus fragmentary, with circular cross section, more thick-set than the index: two strong, basal tubercles, occlusal margin smooth; occlusal opening very broad and curved, with occlusal margins of dactylus and index not in contact. Comparing these specimens with the “classic type ” of cheliped of Eryma von Meyer, 1840 , we have doubts about the attribution of the Malagasy material to it. In Eryma , the cheliped usually shows a stouter, shorter propodus with smooth inner and outer margins; index and dactylus straight, shorter, with occlusal margins tuberculate; occlusal opening narrower, with occlusal margins of dactylus and index in contact. Only the discovery of more complete specimens can resolve the systematic position of these specimens.

Figures

FIG. 11. —?Eryma australe (Secrétan, 1964) from the lower Tithonian of the northern Analavelona Massif,southern Morondava Basin: A, B, holotype (MNHN.F.R03972, southwest of Ankilivalo, gisement 1153), fragmentary cheliped showing very large, compressed propodus with smooth outer margin (A), and strongly tuberculate inner margin (B); index and dactylus curved with occlusal opening very broad, note occlusal margin of index with one row of small rounded teeth and two strong basal tubercles of dactylus. Scale bars: 2 cm. Photographs by C. Lemzaouda (MNHN).