Eryma ventrosum (Meyer, 1835)

(Fig. 12 E-I)

Glyphea ventrosa Meyer, 1835: 329 .

For detailed list of synonymy see Devillez & Charbonnier (2021: 32).

TYPE MATERIAL. — Holotype by monotypy, not located, cast MNHN.F.B12484.

TYPE LOCALITY. — Frétigney, Haute-Saône department, France.

TYPE AGE. — Late Jurassic, early Oxfordian (Terrain à Chailles Formation).

ADDITIONAL EXAMINED MATERIAL. — See Table 1.

DESCRIPTION

Carapace

Subcylindrical carapace; spineless rostrum; fusiform intercalated plate; carapace groove pattern: see diagnosis of Eryma; inflated ω area; flat χ area; carapace densely covered by small tubercles preceded by crescent-shaped depressions; cephalic region with an oblique row of tubercles ended by a strong orbital spine; antennal region with an oblique row of tubercles ended by a strong antennal spine.

DISCUSSION

After Devillez & Charbonnier (2021), the carapace groove pattern, and the carapace ornamentation are diagnostic characters of Eryma ventrosum . One specimen (MHNLM 2008.12.613.8) corresponds to an isolated carapace, which is dorsoventrally flattened (butterfly-shaped carapace) and split along the dorsal midline. This configuration is typical of a molted specimen but the sample is too small to produce a more detailed discussion.