Turbonilla acra

Turbonilla acra
Drawing of a shell of Turbonilla acra
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Heterobranchia clade Euthyneura clade Panpulmonata
Superfamily:	Pyramidelloidea
Family:	Pyramidellidae
Subfamily:	Turbonillinae
Genus:	Turbonilla
Species:	T. acra
Binomial name
Turbonilla acra Dall & Bartsch, 1909 [1]

Turbonilla acra is a species of sea snail, a marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies. ^{[2] [3]}

Description

The milk-white shell is very long and slender. Its length measures 10 mm. (The whorls of the protoconch are decollated.) The 17 whorls of the teleoconch are situated high between the sutures, varying in outline, the first to eleventh being flattened, almost cylindric, with very strongly shouldered summits; the rest moderately well rounded, with less strongly shouldered summits. The axial ribs are very strong on the first 11 whorls, less so and more rounded on the remaining. There are about 14 upon each of the first eleven turns, 22 upon the twelfth, 20 upon the thirteenth, fourteenth, and fifteenth, and about 30 much enfeebled and irregular ones upon the last turn, where they pass over the well-rounded periphery and base to the umbilical region. On the early turns the axial ribs terminate as strong, exserted cusps at the summit; on the last turns they are merely rounded. Early sutures are strongly marked, later ones well impressed. The aperture is ovate. The posterior angle is acute. The outer lip is thin. The slender columella is almost straight, and obliquely inserted. ^[1]

Distribution

The type specimen was found in the Pacific Ocean off Catalina Island, California.

References

1. Dall & Bartsch, A Monograph of West American Pyramidellid Mollusks, United States National Museum Bulletin 68, p. 32: 1909
2. Rosenberg, G. (2011). Turbonilla acra Dall & Bartsch, 1909. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=581297 on 2012-03-01
3. Turgeon, D.; Quinn, J.F.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.; Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. (1998). Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. American Fisheries Society Special Publication, 26. American Fisheries Society: Bethesda, MD (USA). ISBN   1-888569-01-8. IX, 526 + cd-rom pp.

External links

• To World Register of Marine Species