Rhombipoma, Mclean, 2012

Mclean, James Hamilton, 2012, New species and genera of colloniids from Indo-Pacific coral reefs, with the definition of a new subfamily Liotipomatinae n. subfam. (Turbinoidea, Colloniidae), Zoosystema 34 (2), pp. 343-376 : 370

Genus Rhombipoma n. gen.

TYPE SPECIES. — Rhombipoma rowleyana n. sp.

DIAGNOSIS. — Whorl profile low, rounded; with whorl expansion to make final quarter whorl more projecting, sculpture of about 22 axial ribs; axial ribs absent in on final ∕₆ whorl, replaced by more prominent lamellae (lamellae not evident on earlier whorls); the final prominent lamellae continue to form the final lip; spiral sculpture of two beaded cords at periphery; lip very strongly projecting, of eight projecting axial lamellae.

DISTRIBUTION. — Known only from type species, from shallow sublittoral depths, Rowley Shoals, off northwestern Western Australia.

REMARKS

This genus is comparable to Depressipoma n. gen. in its small size and low profile, differing in having a rounded, rather than carinate periphery, and in having reduced spiral sculpture on the shoulder and base, compared to that of Depressipoma n. gen. and Liotipoma . Whorl expansion is most extreme for all members of the subfamily. The final lip is more projecting than in species of Liotipoma and Depressipoma n. gen., and the lamellae of the projecting lip are larger and fewer, matched in prominence by the lamellae that precede the final lip.