Liocarcinus heintzi, Schweitzer & Feldmann, 2010

Schweitzer, Carrie E. & Feldmann, Rodney M., 2010, New fossil decapod crustaceans from the Remy Collection, Muséum national d’Histoire naturelle, Paris, Geodiversitas 32 (3), pp. 399-415 : 410

Liocarcinus heintzi n. sp. ( Fig. 2D )

TYPE MATERIAL. — Holotype (dorsal carapace; MNHN R03778, coll. Remy).

ETYMOLOGY. — Th e trivial name is that used by Jean- Marcel Remy on the museum label in honour of Émile Heintz of the MNHN, Paris , a specialist of fossil mammals, but that was never published. We honour both scientists by using Remy’s intended name.

TYPE LOCALITY. — Monségur, Gironde, Aquitaine, SW France, Rupelian (Stampian), Calcaire à Astéries Formation.

DIAGNOSIS. — Carapace with granular ornamentation on inflated areas of regions; lateral margins crispate; anterolateral spines curving anteriorly.

MEASUREMENTS. — Measurements (in mm) taken on the dorsal carapace: maximum carapace width = 8.4; maximum carapace length = 6.9; length to position of maximum width = 3.3; fronto-orbital width = 6.4; frontal width = 2.5.

DESCRIPTION

Carapace hexagonal, wider than long, length about 80% maximum width, widest at position of last anterolateral spine, about half the distance posteriorly on carapace; carapace weakly vaulted longitudinally and transversely; inflated areas granular; lateral margins crispate, upturned.

Front damaged, about 30% maximum carapace width. Orbits wide, apparently with two fissures, outer-orbital spine triangular, directed forward; fronto-orbital width 75% maximum carapace width.

Anterolateral margins with five spines including outer-orbital spine; second spine broad, triangular, directed forward; third spine smaller, triangular, directed forward; fourth spine about same size as third; fifth spine apparently directed anterolaterally. Posterolateral margin appearing to be weakly concave; posterolateral reentrant large, rimmed; posterior margin nearly straight, rimmed.

Epigastric region inflated, equant. Mesogastric region with long anterior process terminating at posterior end of epigastric regions, widened posteriorly, posterior portion pentagonal,posterior margin nearly straight. Protogastric regions hexagonal, weakly inflated.Urogastric region short, wide. Cardiac region wide, triangular, apex directed posteriorly, with two large, circular swellings anteriorly.Hepatic region depressed, small, flattened.Epibranchial region arcuate, extending from last anterolateral spine to near cardiac region, ornamented with granules. Mesobranchial region with longitudinal, granular swelling parallel and adjacent to axis, smooth laterally.Metabranchial region inflated parallel to posterior margin axially, disappearing laterally, granular.

Remainder of carapace and appendages unknown.

DISCUSSION

Liocarcinus heintzi n. sp. differs from all other species in the genus in possessing granular ornamentation on the most inflated portions of the carapace regions and in having crispate anterolateral margins terminating in upturned, forward directed anterolateral spines. The specimen is rather incomplete, with a broken front and damaged orbits so a complete description is not possible. However, it seems that Liocarcinus is the best generic placement for it at this time.

Figures

FIG. 2. — Fossil Brachyura from Monségur (Gironde, France): A, Planobranchia simplex (Remy, 1960) n. comb., cast of holotype, MNHN R03839,dorsal carapace;B,Planobranchia laevis (Lőrenthey,1909) n. comb.,cast of holotype,IMDASlf.Nr.25520/2005 (dorsal carapace); C, Branchioplax? ballingi Remy in Remy & Tessier, 1954, cast of holotype, MNHN R03793, fragmental dorsal carapace; D, Liocarcinus heintzi n. sp., holotype, R03778, dorsal carapace; E, F, Pleolobites erinaceous Remy, 1960, casts of holotype, MNHN R03782 (E), and MNHN R03781 (F). Scale bars: 1 cm.