Habeastrum parafusum, Simone, 2019

Simone, Luiz Ricardo L., 2019, The new genus Habeastrum, with two new species (Gastropoda, Diplommatinidae) in Mato Grosso do Sul caves, Brazil, Zootaxa 4543 (2), pp. 287-290 : 287-288

Habeastrum parafusum new species ( Figures 1 A–J)

urn:lsid:zoobank.org:act:6CA1A8C0-4891-4F7C-B1C1-489B9E1B89F7 .

Types. holotype MZSP 134301 ( Fig. 1A ). Paratypes : MZSP 135584 , 7 figured shells , MZSP 135585 , 15 shells , MNRJ, 2 shells, USNM, 2 shells all from type locality.

Type locality. BRAZIL. Mato Grosso do Sul, Bonito, Gruta Pitangueiras , 21°06’37”S 56°34’52”W (Trajano & Gnaspini col., 16.vii.1992) .

Diagnosis. Shell with about 7 whorls, 3–4 whorls preceding aperture increasing relatively less in diameter.

Description. Shell turriform, narrowly conical, almost cylindrical. First three whorls slightly sharper pointed,

profile angle ~40°; gradually becoming more cylindrical in 4–5 remaining whorls, with inflation relatively small, outline angle ~20° ( Figs 1 A–G). Total of about 7 whorls. Protoconch 0.39 mm wide, smooth, except for minute radial wrinkles, translucent ( Figs 1H , 10); occupying about 43% of shell width, about 15% of shell length. Teleoconch up to 6 whorls, sometimes with narrow profile ( Figs 1B, F ), sometimes slightly wider ( Figs 1A, C ), sometimes intermediate ( Figs 1D, E, G ). Teleoconch sculpture as for genus (Fig. H), with about 65 axial cords on penultimate whorl. Suture deep, whorl profile rounded. Aperture rounded, not deviating from whorl profile, slightly prosocline ( Figs 1D, G, I ); minimally deformed by penultimate whorl; occupying about 44% of shell width, about 25% of shell length. Umbilicus deep, narrow, occupying about 12% of inferior shell area ( Fig. 1I ).

Distribution. Known only from the type locality, possibly endemic.

Habitat. In soil in caves (no living specimen found).

Measurements (length and width in mm): Holotype 1.4 mm by 0.8 mm ( Fig. 1A ); Paratypes MZSP 135584: #2: 1.7 mm by 0.8 mm ( Fig. 1B ); #3, 1.6 mm by 0.9 mm ( Fig. 1C ); #4, 1.6 mm by 0.8 mm ( Fig. 1D ); #5, 1.4 mm by 0.7 mm ( Fig. 1E ); #6, 1.1 mm by 0.7 mm ( Fig. 1F ); #7, 1.2 mm by 0.7 mm ( Fig. 1G ).

Etymology. The specific epithet refers to the general appearance of the shell, resembling a screw, “ parafuso ” in Portuguese, arbitrarily Latinized with the neutral termination.

Figures

FIGURE 1. Habeastrum spp. shells. A–J. Habeastrum parafusum, n. sp. A. Holotype MZSP 134301, L 1.4 mm. B–J. Paratypes MZSP 135584, L 1.7 mm. C. L 1.6 mm. D. L 1.6 mm. E. L 1.4 mm. F. SEM, L 1.1 mm. G. L. 1.2 mm. H. same specimen, showing protoconch and first teleoconch whorls, SEM, scale = 0.1 mm. I. same specimen of F, scale = 0.1 mm. J. Young specimen, L 0.6 mm. K–R. H. omphalium n. sp. K–N. Holotype MZSP 135583, W 1.1 mm, L 1.6 mm. O–R. Paratypes MZSP 134324. O. L 1.0 mm. P. SEM, L 1.0 mm. Q–R. Scale = 0.1 mm.