Dicharax glaber (W.T. Blanford, 1865)

Figs 44–49

Alycaeus glaber W.T. Blanford, 1865: 84 .

Alycaeus edei Godwin-Austen, 1914: 391–392, pl. 149 figs 2, 2a. Syn. nov.

Alycaeus levis Godwin-Austen, 1914: 394, pl. 138 figs 3, 3a. Syn. nov.

Alycaeus glaber – Sowerby 1877: pl. 4, species 31. — Godwin-Austen 1914: 418–419, pl. 151 fig. 1. Alycaeus (Dicharax) glaber – Kobelt 1902: 371. — Gude 1921: 253.

Alycaeus levis – Gude 1921: 209–210.

Alycaeus (Chamalycaeus) edei – Gude 1921: 227.

Alycaeus (Alycaeus) levis – Ramakrishna et al. 2010: 48.

Chamalycaeus (Chamalycaeus) edei – Ramakrishna et al. 2010: 53.

Dicharax (?) edei – Páll-Gergely et al. 2020: 86.

Dicharax (?) glaber – Páll-Gergely et al. 2020: 89.

Dicharax (?) levis – Páll-Gergely et al. 2020: 92.

Type material examined

MYANMAR • possible syntypes of A. glaber (Fig. 44A–E); Akyab; W.T. Blanford coll.; NHMUK 1906.4.4.181 • 2 shells of ( A. glaber); Akyab, Arakan; NHMUK 20191066 • 8 syntypes of A. edei in 2 vials (Fig. 44F–J); Naraindhur, Cachar; F. Ede leg.; NHMUK 1903.7.1.1665 • holotype of A. levis (single shell mentioned in the original description: Fig. 44K–O); Munipur; Godwin-Austen coll.; NHMUK 1903.7.1.2631 .

Additional material examined

INDIA – Mizoram • 1 empty shell; Blue Mountain, Lawngtlai district; 22.727° N, 93.135° E; 1400 m a.s.l.; 27 Jan. 2019; N.A. Aravind leg.; Ar29; NZSI LM1730 • 1 empty shell; same data as for preceding; Ar39; NZSI LM1731 • 1 empty shell; same data as for preceding; Ar52; NZSI LM1732 • 1 empty shell; same data as for preceding; Ar30; NZSI LM1733 • 1 empty shell; same data as for preceding; Ar64 (Fig. 48); NZSI LM1734 • 2 empty shells; same data as for preceding; Ar54 (Fig. 46); NZSI LM1735 • 2 empty shells; same data as for preceding; Ar20 (Fig. 47B–D [operculum]); NZSI LM1736 • 1 empty shell (Fig. 45); same data as for preceding; Ar19; NZSI LM1737 • 1 empty shell; same data as for preceding; Ar65; NZSI LM1738 • 1 empty shell; same data as for preceding; Ar41 (Fig. 47A); ZSI LM1739 • 1 empty shell; same data as for preceding; Ar28; ZSI LM1905 .

Type localities

“Akyab, Arakan; the hills south of the harbour” ( A. glaber); “Naraindhur, Cachar, No. 1665 B.M.” [probably Narainpur Village, Rajabazar Tehsil, Cachar District: 24°30.4′ N, 92°52.2′ E] ( A. edei); “Gaziphimi, Lahupa Naga Hills, Munipur” [probably Gaziphema, Naga Hills, Manipur: 25°30′ N, 94° 23.3′ E] ( A. levis).

Differential diagnosis

There are few species of Dicharax of this size. For comparisons with other species, see under D. magnus and D. ingrami .

Additional information on the morphology

A cross sectional view of R2 was examined in a specimen (Fig. 48): anterior crust forms a significantly elevated rib, which has an anterior projection (i.e., the R2 ribs are curved towards the aperture); the anterior crust folds over the much weaker posterior crust; microtunnel narrow compared to the ribs, its cross sectional view subcircular.

A D. glaber shell from the Blue Mountain apparently has short chevrons on the inner surface of its aperture (Fig. 47A). The tendency towards a fringed aperture appears in several species (see other examples in Páll-Gergely et al. 2017, 2021).

Operculum (Fig. 47B–D): colour chocolate brown, outer surface multispiral, without elevated lamina, inner side with a strongly elevated, knob-like nipple.

Distribution

This species is known from northeastern Myanmar and the neighbouring Indian areas (Fig. 49).

Remarks

The type specimens of A. glaber, A. edei and A. levis are very similar, and the notable differences (i.e., the more rounded shape of A. glaber and the strongly reflected outer peristome of A. edei) are considered to be intraspecific variability. The shells from the Blue Mountain are identical to the type specimens of A. edei with the exception of the strongly reflected outer peristome (similar cases were reported for D. notus (Godwin-Austen, 1914), see Páll-Gergely et al. 2021: fig. 26).