Redescription of Acmella tersa (Benson, 1853), the type species of Acmella W.T. Blanford, 1869 (Gastropoda: Assimineidae), from Meghalaya, Northeast India

ABSTRACT

The type species of the assimineid genus Acmella W.T. Blanford, 1869 is Cyclostoma tersum Benson, 1853, originally described from ‘Musmai’ [Mawsmai], Meghalaya, Northeast India. No specimens from Benson’s type series can be traced, and contemporary shells collected from the type locality in museum collections are extremely worn. It has therefore been impossible to examine shell microsculpture, an important taxonomic character in the diagnosis of species of Assimineidae, using museum specimens. In order to provide better diagnostic characters for the genus Acmella, we redescribe and illustrate Acmella tersa from newly collected specimens, one of which is designated as the neotype. We also provide a list of all known species attributed to Acmella.

KEYWORDS:

• Musmai
• neotype
• taxonomy
• systematics

Acknowledgements

We would like to thank Meghalaya Forest Department for necessary permission to carry out research (Permit no. SBB.19/ABS/Pt.II/4375), and Ms Anushree Jadhav for help during the field work. NAA and NKD are grateful to Dr Priyadarsanan Dharma Rajan for microscope use and Ms Sneha for help during microscopy. We are grateful to Takuma Haga for providing literature. We thank two anonymous reviewers for comments on an earlier version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Barna Páll-Gergely was supported by the Hungarian Research Fund (OTKA FK 135262), the Bolyai Research Scholarship of the Hungarian Academy of Sciences, the SYNTHESYS Project under Grant GB-TAF-2523, and Department of Biotechnology, Govt. of India for funding (File no. BT/01/17/NE/TAX).