Parvamussium holmesii

(Dall, 1886)




figured syntype

Original name   Amusium (Propeamusium) holmesii Dall, 1886
Autoreference   Dall, 1886: 214, pl. 5, figs 5, 11.
Reference   Dall, W.H., 1886. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U.S. Coast Survey Steamer "Blake", [...]. XXIX. Report on the Mollusca. Part I. Brachiopoda and Pelecypoda. - Bulletin of the Museum of Comparative Zoology 12(6): 171-318, pls 1-9.
Type data

  Syntypes in the Smithsonian Institution, National Museum of Natural History, Washington DC (USNM 62660, 62661), and Museum of Comparative Zoology, Harvard University, Cambridge, USA (MCZ 7797, 7798). Type locality: Caribbean Sea, Barbados, 13*03'N, 59*36'W, 188 m, alive, 05.03.1879 ("Blake" stn 273) and Barbados, 183 m, dead ("Blake" stn ?).


  Shell up to ca. 12 mm high, fragile, opaque, weakly inflated, left valve slightly more convex than right valve, circular, somewhat oblique, inequivalve, inequilateral, anterior auricles larger than posterior, unequal in shape, internal ribs 11-14, umbonal angle ca. 95 degrees, brightly colour.

  Left valve with ca. 20-28 widely and irregularly spaced, radial riblets and intercalated secondary riblets. Weak overrunning commarginal lamellae near ventral margin.

  Right valve with numerous regularly spaced, delicate commarginal lirae. Byssal notch shallow, byssal fasciole very narrow and ctenolium lacking.



Florida, Gulf of Mexico, West Indies, Barbados (TL)

Habitat  Living bathyally on soft bottom assemblages.