Servatrina amazonica, Simone, 2024

Simone, Luiz Ricardo L., 2024, New species, misidentifications and problematic taxonomy of some Atlantic South American marine mollusks: a review, Papéis Avulsos de Zoologia 64, pp. 1-104 : 82-84

Genus Servatrina Iredale, 1939 Servatrina amazonica new species

( Fig. 55 ) https://zoobank.org/ 6E2EE385-EFB2-484B-86B3-395B1D1EDD4A

Types: Holotype MZSP 139952 , specimen . Paratype: MZSP 139953, 2 specimens near type locality, 3.80012°N 50.39266°W, 42.3 m (o.t., sta. 2, 01.viii.2017,Wagner César R. Santos leg.).

Type locality: BRAZIL. Pará ; off Rio Amazonas mouth, 3.94464°N 50.27423°W, 62.8 m [otter trawl, sta. 77, 25.v.2018, Wagner César R. Santos leg.] .

Diagnosis: N Brazilian species, with adult size ~ 160 mm; color light brown. Umbonal angle ~30°. Sculpture 20 radial narrow folds in dorsal half, ~40 similar, but narrow- er folds in ventral half, relatively uniform, lacking scales; folds similar since anterior region.

Description: Shell ~ 160 mm. Basic color uniform light brown, being paler close umbo; walls relatively thick, not translucent. Umbonal angle ~30°. Antero-posteriorly long, ~1.7 times longer than heigh; flattened, ~5.4 times longer than wide ( Fig. 55C ). Middle longitudinal weakly wanting. Sculpture growth lines, with weak concentric undulations in more posterior regions; lacking scales in adult form, some present in young specimen; ~20 radial (longitudinal) folds in dorsal half ( Fig. 55A, B ), all of them narrow, uniform, interspaces 3-4 times wider than folds, in some regions narrow and wide folds intercalated; ventral half with ~40 folds similar to those folds of dorsal region, but narrower and located much closer from each other, interspaces 1-2 times folds width; border between dorsal and ventral set of folds gradual. Dorsal edge straight to weakly convex; ventral edge concave ( Fig. 55A, B ); posterior edge ample, with perpendicular to rounded superior region. Hinge edentulous, with ligament all along it, from anterior beak, up to short region posterior to posterior edge. Posterior region only with opened gap ( Fig. 55C ).

Etymology: The specific epithet is derived from the region of occurrence,off the Amazon river mouth;the term "amazonica " is the Portuguese feminine adjective relative to Amazonian origins.

Distribution: So far known off the mouth of Amazon River, between the Brazilian States of Amapá and Pará.

Figures

Figure 55. Servatrinaamazonica Holotype MZSP 139952 (L 163 mm):(A) left view;(B) right view;(C) ventral view.