Vegrandinia trindadensis ( Breure and Coelho, 1976 ) Salvador & Cunha & Simone, 2013

Salvador, Rodrigo B., Cunha, Carlo M. & Simone, Luiz Ricardo L., 2013, Taxonomic revision of the orthalicid land snails (Pulmonata: Stylommatophora) from Trindade Island, Brazil, Journal of Natural History (J. Nat. Hist.) 47 (13 - 14), pp. 949-961 : 956-957

Vegrandinia trindadensis ( Breure and Coelho, 1976) comb. nov.

( Figure 2M–S )

Bulimulus trindadensis Breure and Coelho 1976: 3 (figs 1–4); Breure 1979; Salgado and Coelho 2003; Simone 2006: 120 (fig. 372).

Holotype

MNRJ 3711 (examined; Figure 2P–Q ).

Paratypes

MNRJ 3712 (many shells, examined) .

Type locality

Cabritos Beach ( Praia dos Cabritos ), Trindade Island: “found imbedded in the loose sediment on the terrace near the beach, away from the tideline” ( Breure and Coelho 1976).

Distribution

Endemic to Trindade Island.

Etymology

Related to the species type locality, Trindade Island .

Diagnosis

Shell an elongated oval; whorl profile flattened; protoconch sculptured by sinuous axial striae; presence of columellar fold reaching aperture and palatal fold beginning ∼ 5 mm away from aperture.

Redescription

Shell diminutive, elongated-oval tending towards conical; about seven whorls; shell width about two-fifths of shell length. Colour white. Spire angle ∼40 ◦. Suture weakly marked. Whorl profile flattened. Protoconch (∼ 11 / 2 whorl) rounded, large, sculptured by sinuous axial striae; transition to teleoconch unclear. Teleoconch smooth. Aperture elliptical, prosocline; callus on parietal region; about one-third shell length, about onehalf shell width. Lip thin, simple, non-reflected, with exception of upper columellar region (reflected and covering umbilicus). Columellar fold on median portion of aperture’s columellar region, beginning ∼ 1 mm inside aperture or reaching aperture. Palatal fold beginning ∼ 5 mm from aperture, on median portion of whorl’s palatal region. Umbilicus rimate.

Measures (in mm)

Holotype. H = 7.0; D = 2.8; S = 4.1; S′ = 3.6; h = 2.5; d = 1.7.

Mean (n = 7; types excluded). H = 4.8 ± 0.3 (max 5.0; min 4.5); D = 2.0 ± 0.1 (max 2.2; min 1.9); S = 3.1 ± 0.2 (max 3.4; min 2.8); S′ = 2.5 ± 0.3 (max 2.8; min 2.1); h = 1.7 ± 0.1 (max 1.8; min 1.6); d = 1.1 ± 0.8 (max 1.3; min 1.0).

Material analysed

BRAZIL. Southwest Trindade Island : MNHN (seven shells); MZSP 104742 (three shells), 104743 (one shell, metallized) . Cabritos Beach ( Praia dos Cabritos ): MNRJ 3711 (one shell, holotype), 3712 (many shells, paratypes) .

Remarks

The species is allocated here to the new monotypic genus Vegrandinia , under the new combination V. trindadensis . Unfortunately, no living specimen was found, so the species’ anatomical features remain unknown. Curiously, the shell length of the adult specimens analysed by Breure and Coelho (1976) averaged from 8 to 9 mm (which was an overestimation, our measures of the same specimens average 7 mm), while the ones collected by the MD-55 and later expeditions average 4.8 mm; the shell morphology, though, is the same. It is suspected that this reduction in size reflects inappropriate environmental conditions due to the Island’s much degraded environment (see Discussion below).

Figures

Figure 2. (A–C) Bulimulus brunoi (holotype, MNRJ 1128; H = 19.4 mm). (D) B. brunoi (MNRJ 1129; H = 20.7 mm). (E, F) B. brunoi, protoconch and teleoconch sculpture (MZSP 101245). (G) Naesiotus arnaldoi (holotype, MNRJ 3105; H = 9.5 mm). (H–J) N. arnaldoi (MZSP 104740; H = 10.8 mm). (K) N. arnaldoi (paratype, MNRJ 3105; H = 10 mm). (L) N. arnaldoi, protoconch sculpture (MZSP 101244). (M–O) Vegrandinia trindadensis (MZSP 104742; 5.2 mm). (P, Q) V. trindadensis (holotype, MNRJ 3711; H = 7 mm). (R, S) V. trindadensis (MZSP 104743), (R) protoconch sculpture, (S) broken aperture showing the lamellae.