Dicharax akhaensis (Godwin-Austen, 1914)

Dicharax akhaensis (Godwin-Austen, 1914) View in CoL

Fig. 59

Alycaeus akhaensis Godwin-Austen, 1914: 352 View in CoL , pl. 141 figs 1, 1a–b.

Alycaeus burroiensis Godwin-Austen, 1914: 354 View in CoL , pl. 141 figs 6, 6a. Syn. nov.

Alycaeus gemma Godwin-Austen, 1914: 355–356 View in CoL , pl. 149 figs 6, 6a. Syn. nov.

Alycaeus ( Dicharax) gemma View in CoL – Gude 1921: 252.

Alycaeus ( Cycloryx) burroiensis View in CoL – Gude 1921: 277.

Alycaeus ( Raptomphalus) akhaensis View in CoL – Gude 1921: 286.

Chamalycaeus ( Dicharax) gemma View in CoL – Ramakrishna et al. 2010: 60.

Chamalycaeus ( Raptomphalus) akhaensis View in CoL – Ramakrishna et al. 2010: 68.

Dicharax (?) akhaensis View in CoL – Páll-Gergely et al. 2020: 76 View Cited Treatment .

Dicharax (?) burroiensis View in CoL – Páll-Gergely et al. 2020: 80 View Cited Treatment .

Dicharax (?) gemma View in CoL – Páll-Gergely et al. 2020: 88 View Cited Treatment .

Diagnosis

This species is characterized by strong, widely-spaced R1 ribs, a short R2+R3, a smooth R2, two low R3 swellings and a slightly fringed peristome.

Type material examined

INDIA • holotype of A. akhaensis (single shell mentioned in the original description: Fig. 59A–E); Akha Hills, Barowli River ; Godwin-Austen coll.; NHMUK 1903.7 About NHMUK .1.2683 • 1 syntype of A. burroiensis ( Fig. 59F–J); Burroi Rr., Dafla; NHMUK 1903.7 About NHMUK .1.2653 • 3 corroded syntypes of A. gemma in two vials ( Fig. 59K–O); No. 7. camp, Dikrang Valley , Dafla; NHMUK 1903.7 About NHMUK .1.2601 .

Type localities

“Barowli Gorge, Durrang District, Assam, foot of the Akha Hills” ( A. akhaensis ); “Burroi Gorge, Dafla Hills” ( A. burroiensis ); “No. 7 Camp, Dikrang Valley, Dafla Hills” ( A. gemma ).

Differential diagnosis

Dicharax lahupaensis (Godwin-Austen, 1914) has a ribbed R2, and its aperture is less fringed.

Remarks

Both A. akhaensis and A. burroiensis are represented in the NHM by single, corroded specimens. Acknowledging that the important characters (mostly the fine sculpture and the formation of R3) could not be very clearly seen on the shells, we could not find any conchological differences that would justify their distinction. Therefore, we treat A. burroiensis as a junior synonym of Dicharax akhaensis . Alycaeus gemma also agrees in all important shell characters (ratios of shell regions, R3 swellings, fringed aperture), but its shell has a rather oval outline in dorsal view. Nevertheless, this is also considered part of intraspecific variability, and therefore, A. gemma is also treated as a junior synonym of A. akhaensis . See also under D. khasiacus .