Clappia umbilicata

Umbilicate pebblesnail
Drawing of apertural view of the shell and its operculum of Clappia umbilicata
Conservation status
Extinct (IUCN 2.3)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha
Superfamily:	Rissooidea
Family:	Lithoglyphidae
Genus:	Clappia
Species:	†C. umbilicata
Binomial name
Clappia umbilicata (Walker, 1904)[2]
Synonyms[1][4]
Somatogyrus umbilicatus Walker, 1904 Lithoglyphus umbilicata Walker, 1904 Clappia clappi Walker, 1909[3]

The umbilicate pebblesnail, scientific name Clappia umbilicata, is an extinct species of a small freshwater snails that had an operculum, aquatic gastropod mollusks in the family Lithoglyphidae.^[5]

Distribution

This species was endemic to the Alabama, United States.^[1] The type locality is Coosa River at Wetumpka, Alabama.^[2]

Its distribution included: Coosa River at Duncan's Ripple, The Bar and Higgin's Ferry in Chilton County; and Butting Ram Shoals in Coosa County, Alabama.^[3][6]

• 

  Chilton County, Alabama (marked red) where the species was found.

• 

  Coosa County, Alabama (marked red) where the species was found.

Description

This species has been discovered and described under the name Somatogyrus umbilicatus by American malacologist Bryant Walker in 1904.^[2] Walker's type description reads as follows:

Drawing of apertural view of the shell of Clappia umbilicata from its type description by Bryant Walker.

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 AVetumpka, and only a single example was collected at Fort Williams Shoals.

”

The color of Clappia umbilicata was black.^[3] It presumably mean the whole animal including snout, nape, mantle and foot.^[5] The black color of the mantle has been verified by Thompson (1984).^[5]

Clappia umbilicata has 56-59 rows of teeth on its radula.^[5] Each row has 6-7 central basocones, 6-7 central octocones, 18-21 lateral teeth, ca. 50 inner marginal teeth and ca. 35 outer marginal teeth.^[5]

Ecology

Jordan Dam altered the habitat of Clappia umbilicata at Coosa River so much, that it died out

Its natural habitat was rivers.^[1] Clappia umbilicata required rapid flowing sections of river shoals.^[5] It died out because of silting of its habitat after the dam was constructed^[1] (Jordan Dam and Jordan Lake).

Based on examination of radula, Thompson (1984)^[5] hypothesized, that Clappia umbilicata was grazing on fine particles of plants and it was specialized on more fine partiecles than the genus Somatogyrus.^[5]

References

This article incorporates public domain text from reference^[2][6]

1. ^ ^{a b c d e} Mollusc Specialist Group (2000). Clappia umbilicata. 2006 IUCN Red List of Threatened Species. Downloaded on 6 August 2007.
2. ^ ^{a b c d} Walker B. (1904). "New species of Somatogyrus". The Nautilus 17(12): 133-142. page 137. plate 5, figure 5.
3. ^ ^{a b c} Walker B. (1909). "New Amnicolidae from Alabama". The Nautilus 22(9): 85-90. page 89.
4. ^ Kabat A. R. & Hershler R. (1993). "The prosobranch snail family Hydrobiidae (Gastropoda: Rissooidea): review of classification and supraspecific taxa". Smithsonian Contributions to Zoology 547: 1-94. page 18. PDF.
5. ^ ^{a b c d e f g h} Thompson F. G. (1984). "North American freshwater snail genera of the hydrobiid subfamily Lithoglyphinae". Malacologia 25(1): 109-141.
6. ^ ^{a b} Clench W. J. (1965). "A new species of Clappia from Alabama". The Nautilus 79(1): 33-34. Figure 2.

External links