Clappia umbilicata

This species was endemic to the State of Alabama in the United States.[1] The type locality is the Coosa River at Wetumpka, Alabama.[3]

The distribution of this species used to include: Coosa River at Duncan's Ripple, The Bar and Higgin's Ferry in Chilton County; and Butting Ram Shoals in Coosa County, Alabama.[5][7]

• 
  Chilton County, Alabama (marked red) where the species was found
• 
  Coosa County, Alabama (marked red) where the species was also found

This species was discovered and described under the name Somatogyrus umbilicatus by the American malacologist Bryant Walker in 1904.[3] Walker's type description reads as follows:

Drawing of selected radular teeth of Clappia umbilicata: central tooth, lateral tooth, inner marginal tooth and outer marginal tooth.

Somatogyrus umbilicatus n. sp. Pl. v, fig. 5.

Shell small, globosely depressed, umbilicate, light greenish-yellow, smooth, except for the fine, rather unequal, lines of growth. Spire short, obtusely elevated. Whorls 3½ those of the spire convex and separated by a well-impressed suture; body whorl large, gibbously convex. Aperture sub-circular, rather longer than broad, obtusely angled above and slightly flattened along the basal margin. Columella concave, narrowly reflected; columellar callus, moderately heavy, rounded, reflected over but not concealing the round, deep umbilicus, thin and transparent on the parietal wall. Alt. 3, diam. 3 mm.

Coosa river at Wetumpka, Ala. (type locality), also at Fort Williams Shoals above Farmer, Ala.

This species is remarkable for its depressed, valvata-like form and round, deep umbilicus, which readily differentiates it from all other known species of the genus. It does not appear to be very abundant at Wetumpka, and only a single example was collected at Fort Williams Shoals.

The color of Clappia umbilicata was black.[5] This presumably means that the whole animal including snout, nape, mantle and foot were black.[6] The black color of the mantle was verified by Thompson (1984).[6]

Clappia umbilicata has 56-59 rows of teeth on its radula.[6] Each row has 6-7 central basocones, 6-7 central ectocones, 18-21 lateral teeth, ca. 50 inner marginal teeth and ca. 35 outer marginal teeth.[6]

Jordan Dam on the Coosa River altered the habitat of Clappia umbilicata so much that the snail died out completely.

The natural habitat of this species was rivers.[1] Clappia umbilicata inhabited only the rapidly flowing sections of river shoals.[6] The snail died out because of silting of its habitat after the dam was constructed in 1928.[1] (Also see Jordan Dam and Jordan Lake).

Based on examination of the radula, Thompson (1984)[6] hypothesized that Clappia umbilicata grazed on fine particles of plants, specializing on finer-sized particles than those consumed by snails in the genus Somatogyrus.[6]

This article incorporates public domain text from reference[3][7]