Gastrocopta sharae, Salvador, Rodrigo B., Cavallari, Daniel C. & Simone, Luiz R. L., 2017

Salvador, Rodrigo B., Cavallari, Daniel C. & Simone, Luiz R. L., 2017, Taxonomical study on a sample of land and freshwater snails from caves in central Brazil, with description of a new species, Zoosystematics and Evolution 93 (1), pp. 135-141 : 135-136

Gastrocopta sharae sp. n. Figs 2-6

Type material.

Holotype: MZSP 122725 (Figs 2-4). Paratype: MZSP 122726, from type locality (Figs 5-6).

Type locality.

BRAZIL, Goiás, Mambaí, Gruta Revolucionários (col. M.E. Bichuette, J.E. Gallão, D.M. Shimonsky, P.P. Rizzato, R. Borghezan; 29/iv/2013).

Distribution.

Known only from the type locality (Fig. 1).

Etymology.

The name refers to Shar, a fictional goddess of darkness, caverns, and secrets, from the Faerûnian pantheon of the Forgotten Realms campaign setting of the Dungeons and Dragons role-playing game.

Diagnosis.

Shell pupilloid-conical. Four apertural barriers: two lamellae and two teeth). Anguloparietal lamella shaped like narrow gutter, bent towards palatal region.

Description.

Shell minute (H <2 mm), pupilloid-conical; greatest width of shell on body whorl (D/H = 0.6); body whorl ca. 1/2H; spire angle 48°. Whorl profile greatly convex; suture well-marked. Protoconch (ca. 1½ whorl) round, smooth; transition to teleoconch clearly marked by change to teleoconch sculpture. Teleoconch sculptured by strongly prosocline faint axial riblets. Aperture rounded to lightly quadrangular (d/h = 0.8; h/H = 0.4); peristome reflexed; parietal callus distinctive. Apertural barriers totaling four (Fig. 3): upper palatal tooth, lower palatal tooth, columellar lamella, anguloparietal lamella. Anguloparietal lamella shaped like narrow gutter, bent towards palatal region. After the anguloparietal lamella, the strongest barriers are the lower palatal tooth and columellar lamella. Umbilicus narrow, deep.

Dimensions

(in mm). Holotype: 4¼ whorls; H = 1.9; D = 1.1; h = 0.7; d = 0.6. Paratype: 4¼ whorls; H = 1.9; D = 1.1; h = 0.7; d = 0.6.

Discussion.

The minute pupilloid shell and the pattern of apertural barriers, especially the presence of an anguloparietal lamella (formed by the fusion of the angular and parietal lamellae), place the present specimens in Gastrocopta . They are sufficiently different and easily diagnosable from all known Gastrocopta species in Brazil, which warrants the description of a new species: Gastrocopta sharae sp. n. Although each of the diagnostic features of Gastrocopta sharae can be found separately in congeners (e.g., Pilsbry 1916-1918), their occurrence together is unique for this species.

Gastrocopta sharae can be easily distinguished by its strongly conical shell (Figs 2, 3, 5, 6). Nearly all Brazilian species have more pupiform/cylindrical shells: Gastrocopta barbadensis (Pfeiffer, 1853) (Fig. 7), known from the Caribbean Islands, Venezuela, Fernando de Noronha Archipelago and Trindade Island ( Cunha et al. 2015); Gastrocopta iheringi (Suter, 1900) (Fig. 8), known only from Rio Grande do Sul state ( Simone 2006); Gastrocopta oblonga (Pfeiffer, 1852) (Fig. 9), known from Suriname to Argentina ( Simone 2006); and Gastrocopta servilis (Gould, 1843) (Fig. 10), known from Ceará and Rio de Janeiro states ( Simone 2006). Gastrocopta solitaria (Smith, 1890) (Fig. 11), from Fernando de Noronha Archipelago, is somewhat conical, but not nearly as much as Gastrocopta sharae .

Likewise, Gastrocopta sharae is easily diagnosable by its narrow gutter-like anguloparietal lamella (Fig. 4), slightly bent towards the palatal region of the aperture. All the Brazilian species present a bifid weak anguloparietal lamella, with the single exception of Gastrocopta iheringi (Fig. 8). The latter also has a gutter-like lamella, but it is much broader and straight (i.e., not bent towards the palatal region). Moreover, Gastrocopta iheringi is much taller than Gastrocopta sharae , reaching a shell length of 2.5 mm; this might not seem a large difference at first sight, but differences of this magnitude are usually considered to be interspecific in the family.