Dicharax umbonalis ( Benson, 1856 )

Dicharax umbonalis ( Benson, 1856) View in CoL

Fig. 51F–N

Alycaeus umbonalis Benson, 1856: 225–226 View in CoL .

Alycaeus sandowayensis Godwin-Austen, 1914: 423–424 View in CoL , pl. 139 figs 4, 4a. Syn. nov.

Alycaeus umbonalis View in CoL – Sowerby 1877: pl. 4, species 36. — Godwin-Austen 1886: 194–195, pl. 44 figs 2, 2a–c; 1914: 413, 424.

Alycaeus ( Chamalycaeus) umbonalis View in CoL – Kobelt 1902: 364. — Gude 1921: 235–236.

Alycaeus ( Chamalycaeus) sandowayensis View in CoL – Gude 1921: 232.

Dicharax (?) sandowayensis View in CoL – Páll-Gergely et al. 2020: 103 View Cited Treatment .

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

Diagnosis

This species differs from all other congeners of this species group by the wide umbilicus and less inflated R2.

Type material examined

MYANMAR • holotype of A. sandowayensis (single shell mentioned in the original description: Fig. 51F–J); Mai-i, Sandoway Dist. , Arakan; Stoliczka leg.; NHMUK 1903.7 About NHMUK .1.2558 • 3 syntypes of A. umbonalis ( Fig. 51K–N); Burmah; UMZC I.103005 .

Additional material examined

MYANMAR • 5 shells of A. umbonalis ; Akoutong, Burma; Blanford coll.; NHMUK.

Type localities

“ad Akaouktong, prope ripas fluvii Irawadi ” ( A. umbonalis ); “Mai-i, Sandoway District, Arakan ” ( A. sandowayensis ).

Remarks

The holotype of A. sandowayensis is a smaller shell than typical A. umbonalis , but since all shell characters are identical, we treat it as a synonym of the latter species. In the original description of A. sandowayensis, Godwin-Austen (1914) did not compare it with any other species.