Gastrocopta caatinga, Lima & Abreu, 2024

Lima, Silvio Felipe Barbosa & Abreu, Evandro Cosmo Tomaz de, 2024, New land microsnails of the genus Gastrocopta (Eupulmonata: Gastrocoptidae) in the semiarid region of Brazil, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 64, pp. 1-8 : 5

Gastrocopta caatinga sp. nov.

( Fig. 3)

Type material: Holotype – UFPB.MOL-44075 ( Fig. 3); paratypes – UFPB.MOL-44076 (1 shell) and CMPHRM7522B (1 shell), all from type locality.

Type locality: Brazil, Paraíba, municipality of São José de Piranhas, EAEP,sampling area 17, 06°59′23″S, 38°27′28″W (404 m), litter (leaf and soil), 10.II.2018, Evandro C. T. Abreu collector.

Etymology: The specific name honors the phytogeographic domain of the Caatinga – from the Tupi-Guarani, meaning "white forest″ referring to the landscape consisting of leafless vegetation and whitish trunks typical of the dry season, or a large geographic area covering the greater part of northeastern Brazil characterized by the variety of vegetation cover, which is usually deciduous and hyperxerophilic.

Diagnosis: Apertural barriers with four teeth that do not obstruct the region (except for projection of parieto-angular tooth). Parieto-angular tooth longest of all teeth, slightly bifid, recurved to right, located at midpoint of parietal region. Upper palatal tooth minute. Lower palatal tooth rounded, second biggest tooth. Columellar tooth low, semicircular, slightly oblique (diagonal) to columellar axis, located at midpoint of columellar wall.

Description: Shell dextral, whitish to light cream, thin, minute (length about 1.2 mm), ovoid ( Figs. 3 A-C). Apex cap shape, apically subflattened. Protoconch worn, apparently smooth, with about 1.5 whorl;proto-teleoconch transition marked by faint edge and appearance of numerous, faint growth striations ( Fig. 3E). Spire moderately convex (about 60% of total length). Teleoconch with about 4 inflated, globose, moderately convex whorls, increasing moderately in size,sculptured by closely spaced, rather regular, faint, fine, prosocline axial riblets visible on unworn surface ( Figs. 3 A-C). Body whorl with about 40% of total length, expanded, strongly oval, width about 68 to 69% of total length of shell ( Figs. 3 A-C). Umbilicus large and rounded. Suture well impressed, moderately deep, slightly oblique (diagonal) to columellar axis ( Figs. 3 A-C). Peristome slightly reflexed (little more prominent on columellar area), rounded in columellar to lower palatal area, flattened in upper palatal area; suprapalatal region with distinct angulation. Lip moderately thickened, narrow. Aperture subsquare, about 37 to 38% of total length. Apertural barriers with four teeth that do not obstruct region (except for projection of parieto-angular tooth), not extending to lip margin. Parieto-angular tooth longest of all teeth slightly bifid, recurved to right located at midpoint of parietal region. Upper palatal tooth minute. Lower palatal tooth rounded, second larger tooth. Columellar tooth low, semicircular, slightly oblique (diagonal) to columellar axis, located at midpoint of columellar wall ( Figs. 3A, C-D).

Geographical distribution: Known only from the municipality of São José de Piranhas, Paraíba, Brazil.

Remarks: Gastrocopta caatinga sp. nov. differs substantially from native and invasive Brazilian congeners in having basically an ovoid shape ( Figs. 3 A-C) and apertural barriers with distinctive size,outline and/or inclination of the dentition ( Figs. 3A, D). In Brazilian phytogeographical domains, there is no species of Gastrocopta with shell morphology similar to G. caatinga sp. nov.

The new species superficially resembles G.barbadensis [ Cunha et al., 2015:fig. 2D], G.iheringi [ Simone, 2006: fig. 346], G. oblonga [ Simone, 2006: fig. 347] and G. solitaria [ Simone, 2006: fig. 349] in the outline of the teleoconch whorls; G. barbadensis in the distinct angulation of the suprapalatal region; G. oblonga in its subsquare aperture; and G. sharae [ Salvador et al., 2017: figs. 2-6] in the arrangement of teeth on the columellar and palatal areas.