''Callogaza watsoni'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of sea snail, a marine gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Margaritidae Margaritidae is a family of small sea snails, marine gastropod mollusks in the superfamily Trochoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Margaritidae. Accessed through: World Register ...

Description

The slightly nacreous shell reaches a length of 15 mm. It contains 6¼ whorls having the same general form as in '' Gaza fischeri'', but with a more prominent nucleus. This nucleus is small, bulbous, and dark brown. The first 2½ whorls are glassy, brown spotted, smooth. Subsequently, the exterior two-thirds of the upper surface of the whorls are sculptured with four or five strong revolving threads. The space between them and the suture above contains strong, even, flexuously radiating, shining, rounded plications (about eight to a millimeter) which pass obliquely over the revolving threads and appear again on the base as strong regular plications in the umbilical region, extending from the umbilical carina one-third of the way toward the periphery. The base of the shell is covered with numerous revolving threads flattened until their interspaces appear like grooves. The umbilicus is similarly formed to '' Gaza fischeri'', but somewhat more turreted internally. The body whorl is less contracted behind the

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

, which is not produced forward above. The umbilical callus is not nacreous. It has a granular surface, white and covering less than half the umbilicus. The lip and the

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

oare only slightly nacreous. The base of the shell is waxy white. The top is the same, with cloudy radiating brown blotches near the suture and on the periphery. Some of the revolving threads are also continuously brown.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This species occurs in the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

and in the Atlantic Ocean off

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

References

Luiz Ricardo L. Simone & Carlo M. Cunha, ''Revision of genera Gaza and Callogaza (Vetigastropoda, Trochidae), with description of a new Brazilian species''; Zootaxa1318: 1–40 (2006)
* Rosenberg, G., F. Moretzsohn, and E. F. García. 2009. ''Gastropoda (Mollusca) of the Gulf of Mexico,'' Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas {{DEFAULTSORT:Callogaza Watsoni watsoni Gastropods described in 1881