Dicharax succineus (W.T. Blanford, 1862 )

Dicharax succineus (W.T. Blanford, 1862) View in CoL

Figs 77–80

Alycaeus succineus W.T. Blanford, 1862: 139–140 View in CoL .

Alycaeus vulcani W.T. Blanford, 1863: 323 View in CoL . Syn. nov.

Alycaeus blanfordi Godwin-Austen, 1914: 418 View in CoL , pl. 148 fig. 3. Syn. nov.

Alycaeus succineus View in CoL – Sowerby 1877: pl. 2, species 16. — Godwin-Austen 1914: 424, pl. 151 fig. 2.

Alycaeus vulcani View in CoL – Sowerby 1877: pl. 2, species 17. — Godwin-Austen 1914: 413–414, pl. 151 figs 5, 5a. — Gude 1921: 221–222.

Alycaeus ( Dicharax) succineus View in CoL – Kobelt 1902: 377. — Gude 1921: 271–272.

Alycaeus ( Alycaeus) vulcani View in CoL – Kobelt 1902: 352.

Alycaeus blanfordi View in CoL – Gude 1921: 206.

Chamalycaeus vulcani View in CoL – Páll-Gergely et al. 2020: 48 View Cited Treatment .

Dicharax (?) succineus View in CoL – Páll-Gergely et al. 2020: 106 View Cited Treatment .

Dicharax (?) blanfordi View in CoL – Páll-Gergely et al. 2020: 106 View Cited Treatment .

Diagnosis

The large shell, widely-spaced ribs, the long R2, relatively low R3 swelling and the fringed aperture distinguish this species from its congeners. Based on the lamella-like ribs, this species rather resembles species of Chamalycaeus and Metalycaeus (e.g., M. brahma , see Páll-Gergely et al. 2020), but lacks the spiral striation on its entire shell.

Type material examined

MYANMAR • 1 syntype of A. succineus ( Fig. 77A–E); Tangoop Pass, Arakan Hills ; NHMUK 1906.4 About NHMUK .4.52 • holotype of A. blanfordi (single specimen mentioned in the original description: Fig. 77F– J); Chwegalé, Arakan Hills ; NHMUK 1906.4 About NHMUK .4.177 • 1 shell, labelled as syntype of A. vulcani ; Ava, Burma ; MCZ 135705 About MCZ • 4 shells, possible syntypes of A. vulcani ; Puppadoung; ex coll. Theobald; NHMUK 1888.12.4.939-942 • 2 shells (possible syntypes of A. vulcani ); Puppa Hill, Ava; Blanford leg.; Crosse coll. 1899, Sykes coll. 1954; NHMUK • possible syntypes of A. vulcani ( Fig. 78A–E); Pupa Hills, Burma , extinct volcano; W.T. Blanford coll.; NHMUK 1906.4 About NHMUK .4.49 • possible syntypes of A. vulcani ( Fig. 78F–J); Puppa Ava, Burma ; H.F. Blanford coll., ex coll. auctoris; NHMUK 20160325 About NHMUK .

Additional material examined

INDIA – Mizoram • 1 empty shell ( Fig. 79); Blue Mountain, Lawngtlai district ; 22.727° N, 93.135° E; 1400 m a.s.l.; 27 Jan. 2019; N.A. Aravind leg.; Ar 70; NZSI LM1727 View Materials GoogleMaps • 2 empty shells; same data as for preceding; Ar26; NZSI LM1728 View Materials GoogleMaps • 1 empty shell; same data as for preceding; Ar22; NZSI LM1729 View Materials GoogleMaps .

Type localities

“in montibus Arakanensibus” ( A. succineus ); “on the upper portion of the isolated peak of Puppa, an extinct volcano lying ca 40 miles E. S. E. of the town of Pu-gán in the territories of the king of Ava” ( A. vulcani ); “Chwegali, Arakan Hills” [probably Chaingalain Village, Rati Taung: 20°23.8’N 92°39.9’E] ( A. blanfordi ).

Distribution

This species is known from the western part of Myanmar and the Indian state of Mizoram ( Fig. 80).

Remarks

The type specimens of Alycaeus blanfordi , A. succineus and A. vulcani are nearly identical. There is no notable difference in shell size, shape, and sculpture. Therefore, they are treated as synonyms, and the oldest name, D. succineus , is valid. Blanford (1863), when describing D. vulcani , compared that species with D. succineus , and wrote that it was more globose than A. succineus . The opposite is true; the syntype of A. succineus is slightly more globular than that of A. vulcani , although the difference represents intraspecific variability. Godwin-Austen (1914) did not compare A. blanfordi with any other species and only noted that the species had very distinctive characters and was worthy of being named.

The specimens from the Blue Mountain differ from the ones from the Arakan Mountains ( types of A. blanfordi , A. succineus and A. vulcani ) by having a glossy R3, while that of the specimens in the Arakan Mountains are matte with some growth lines. We consider this difference insufficient for species-level distinction.