Mursia sp.

Italy, Nw, Pasini, Giovanni, Garassino, Alessandro & Damarco, Piero, 2018, Short Communication Report of brachyuran crabs (Crustacea, Decapoda) from the Pliocene of Borgomanero, Novara (Piedmont, NW Italy), Natural History Sciences 5 (2), pp. 12437-12437 : 12437-

Mursia sp. ( Fig. 3 )

Material and measurements: One carapace in dorsal view ( MSNM i28549 – lcxp: 12 mm; wcxp: 15 mm).

Description: Carapace small, ovate distinctly vaulted transversely with five ridges of tubercles, wider than long, with maximum width in middle portion; convex anterolateral margins with several spaced tubercles or blunt teeth, arcuate anteriorly to the level of cardiac region; posterolateral margins strongly narrowed posteriorly, with straight narrow posterior margin; narrow frontal margin protruding anteriorly, poorly preserved; rounded small orbits forward directed; main dorsal regions marked by grooves; gastric regions defined by deep grooves, sepa- rated axially from branchial regions; grooves with some sparsely unequal tubercles; branchial regions with two additional shallow longitudinal grooves in each branchial region, the most lateral ones less deep; rounded tuberculate subparallel longitudinal ridges presents among the grooves; medial ridge stronger, bearing four-five large well-developed single tubercles arranged longitudinally and two pairs of transverse paired tubercles on the frontal region; similar arrangement of single less prominent tubercles decreasing posteriorly, present on the two shorter lateral branchial ridges.

Discussion. The studied specimen is herein referred to Mursia Leach in Desmarest, 1822 based upon the shape and ornamentation of the carapace, five dorsal ridges of tubercles, and narrow posterior margin. One peculiar difference with the majority of extant and fossil species of Mursia is the lack of one lateral spine (more or less developed) and reduced carapace ornamentation, though these characters are shared with M. aspina Schweitzer & Feldmann, 2000 from the late Eocene of Washington, USA ( Schweitzer & Feldmann, 2000: 236, 237, Figs. 5.3-6, 7). However, it is not possible to verify on the studied specimen if the lateral spine is really absent, broken or simply worn due to the badly preservation.

The presence of Mursia is herein reported for the first time from the Pliocene Mediterranean basin.

Figures

Fig. 3 - Mursia sp., MSNM i28549 (x 5).