Parahyas, Charbonnier & Garassino & Pasini & Chény, 2024

Parahyas n. gen.

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ETYMOLOGY. — A combination between Para (Latin: similar to) and the extant genus Hyas Leach, 1814 . The gender of the genus is masculine.

TYPE SPECIES. — Hyas oranensis Van Straelen, 1937 .

DIAGNOSIS. — Carapace pyriform; orbit composed of supraorbital rim and widely cup-shaped postorbital spine bearing marginal spines; inflated branchial regions with posterolateral margin bearing row of tubercles; intestinal region protruding distally beyond and under branchial regions; urogastric and cardiac regions limited by deep branchiocardiac groove.

DISCUSSION

Parahyas n. gen. is assigned to the Oregoniidae based upon the widely cup-shaped postorbital spine, which is well visible in several extant representatives such as Hyas coarctatus Leach, 1815 and H. ursinus Rathbun, 1924 . Parahyas n. gen. differs from Oregonia , Chionoecetes , Macroregonia by the presence of widely cup-shaped postorbital spine (absent in all these genera). Parahyas n. gen. differs from Hyas by the presence of a row of large tubercles extending along the entire length of the posterolateral margin ( versus sometimes scarce small tubercles along the margin in Hyas ), dorsal surface of carapace covered by small tubercles arranged uniformly ( versus scattered granules and tubercles of varying size in Hyas ), and gastric, urogastric, and cardiac regions without median raised tubercles ( versus above-mentioned regions with raised median tubercles in Hyas ).