Dicharax glaber (W.T. Blanford, 1865 )

Dicharax glaber (W.T. Blanford, 1865) View in CoL

Figs 44–49

Alycaeus glaber W.T. Blanford, 1865: 84 View in CoL .

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

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

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

Alycaeus levis View in CoL – Gude 1921: 209–210.

Alycaeus ( Chamalycaeus) edei View in CoL – Gude 1921: 227.

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

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

Dicharax (?) edei View in CoL – Páll-Gergely et al. 2020: 86 View Cited Treatment .

Dicharax (?) glaber View in CoL – Páll-Gergely et al. 2020: 89 View Cited Treatment .

Dicharax (?) levis View in CoL – Páll-Gergely et al. 2020: 92 View Cited Treatment .

Type material examined

MYANMAR • possible syntypes of A. glaber ( Fig. 44A–E); Akyab ; W.T. Blanford coll.; NHMUK 1906.4 About NHMUK .4.181 • 2 shells of ( A. glaber ); Akyab , Arakan; NHMUK 20191066 About NHMUK • 8 syntypes of A. edei in 2 vials ( Fig. 44F–J); Naraindhur, Cachar ; F. Ede leg.; NHMUK 1903.7 About NHMUK .1.1665 • holotype of A. levis (single shell mentioned in the original description: Fig. 44K–O); Munipur ; Godwin-Austen coll.; NHMUK 1903.7 About NHMUK .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.; Ar 29; NZSI LM1730 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar 39; NZSI LM1731 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar 52; NZSI LM1732 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar 30; NZSI LM1733 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar64 ( Fig. 48); NZSI LM1734 View Materials GoogleMaps • 2 empty shells; same data as for preceding; Ar54 ( Fig. 46); NZSI LM1735 View Materials GoogleMaps • 2 empty shells; same data as for preceding; Ar 20 ( Fig. 47B–D [operculum]); NZSI LM1736 View Materials GoogleMaps • 1 empty shell ( Fig. 45); same data as for preceding; Ar 19; NZSI LM1737 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar 65; NZSI LM1738 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar41 ( Fig. 47A); ZSI LM1739 GoogleMaps • 1 empty shell; same data as for preceding; Ar 28; ZSI LM1905 GoogleMaps .

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).