Eryma granuliferum Secrétan, 1964

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

Eryma granuliferum Secrétan, 1964 ( Fig. 10 )

Eryma granulifera Secrétan, 1964: 64-67 , pl. 1, fig. 1; pl. 3, fig. 1.

Eryma madagascariensis Secrétan, 1964: 61-64 , pl. 3, figs 2, 3. n. syn.

Eryma granulifera – Förster 1966: 125. — Feldmann & Titus 2006: 64.

Eryma granuliferum – Schweitzer et al. 2010: 24.

Eryma madagascariensis – Förster 1966: 116, 125, 162. — Feldmann & Titus 2006: 64. — Schweitzer et al. 2010: 24.

HOLOTYPE. — MNHN.F. R 03975.

TYPE LOCALITY. — Eastern Antsalova (gisement 236), south of the Maintirano region, northern Morondava Basin, Tulear Province.

TYPE AGE. — Middle Kimmeridgian (Hibononticeras hibonotum and Aspidoceras acanthicum zone).

ADDITIONAL MATERIAL EXAMINED. — Specimen MNHN.F. R 03974 (holotype of Eryma madagascariensis ), Antsalova, east of Mount Ambohidroa (gisement 233)

Aspidoceras longispinum and Torquatosphinctes alterneplicatus zone, Lower Kimmeridgian, north of the Manambolo River, south of the Maintirano region, northern Morondava Basin, Tulear Province.

STRATIGRAPHIC RANGE. — Early to Middle Kimmeridgian.

DIAGNOSIS. — Cephalothorax with deep cervical and antennal grooves; postcervical and branchiocardiac grooves parallel and slightly marked; branchiocardiac groove connected with deep hepatic groove; postcervical groove not joined to branchiocardiac groove and interrupted prior to the junction with the hepatic groove; inferior groove not well marked.

DESCRIPTION

Cephalothorax subcylindrical (CL = 25 mm, CH = 17 mm); very small rostrum (length c. 2 mm) with rounded distal extremity and smooth margins; ocular incision rather shallow; gastric and antennal region well delimited between cervical and antennal grooves; inflated antennal region; very narrow cardiac region; wide, rounded branchial region; cervical groove near-right with a weak depression at mid-height, slightly inclined intercepting dorsal margin at an angle of c. 65°; postcervical and branchiocardiac grooves strongly inclined intercepting dorsal margin at an angle of c. 40°; hepatic groove strongly rounded; inferior groove not well marked; posterior margin with small carina; ornament uniform with small tubercles.

Abdomen with subrectangular somites of uniform length; pleurae 1 and pleurae 4 and 5 with spiny ventral margin; tail fan not preserved; surface of somites smooth with sparse pits.

Pereiopods fragmentary (three different segments preserved, difficult to attribute to pereiopod).

DISCUSSION We concur with Förster’s (1966) diagnosis of Eryma as well as with Secrétan’s (1964) reference of the Malagasy material to this genus. Secrétan (1964)

differentiated Eryma granulifera from E. madagascariensis on the presence of an anterior branch of the postcervical groove interrupted prior to joining the hepatic groove. Our re-examination of the type specimen of E. granuliferum has clearly shown that the postcervical groove is not divided into two branches. Moreover, the branchiocardiac groove is connected with the hepatic groove and not with the postcervical groove, as assumed by Secrétan (1964). Finally, the postcervical and branchiocardiac grooves are parallel, not fused. This configuration is similar in both E. granuliferum and E. madagascariensis , which is why we consider them to be conspecific, the name E. granuliferum being chosen as the valid name, on the basis of the Principle of the First Reviser ( ICZN 1999: art. 24.2).

Figures

FIG. 10. — Eryma granuliferum Secrétan, 1964 from the lower to middle Kimmeridgian of Antsalova, south of the Maintirano region, northern Morondava Basin: A, holotype (MNHN.F.R03975, eastern Antsalova, gisement 236), complete cephalothorax in left lateral view; B, C, incomplete specimen (MNHN.F.R03974, holotype of Eryma madagascariensis, gisement 233, Antsalova, east of Mount Ambohidroa), right lateral view (B) and detail of cephalothorax (C); D, line drawings by F. Fogliazza in left lateral view. Abbreviations: a, branchiocardiac groove;b, antennal groove;b1, hepatic groove;c, postcervical groove;e1e, cervical groove;i, inferior groove.Scale bars: 2 cm. Photographs by C. Lemzaouda (MNHN).