Chaetonotus trianguliformis Visvesvara 1964

Chatterjee, Tapas & Todaro, M. Antonio, 2021, An annotated checklist of the chaetonotidan Gastrotricha from India, Zootaxa 5027 (3), pp. 332-350 : 340-341

Chaetonotus trianguliformis Visvesvara 1964

Records from India. MAHARASTRA: Nagpur – Visvesvara (1964); GENERAL RECORD: Naidu & Rao (2004), Purushothaman (2017).

Habitat (as in Indian records). Freshwater; among aquatic vegetation.

Distribution. Known only from India.

Remarks. This species was found only once (see below). The description of the cuticular ornamentations of this species is puzzling. According to the author, the simple spines possessed by this species originate from a triangular base that “… at higher dry objective appear as scales but when examined under oil, scales were not discernible ”. The author concludes that spines originate from a triangular elevation scales are not present. In our opinion, a new description based on living material is needed to clarify this aspect. Naidu & Rao (2004), following Schwank’s (1990) classification, placed this taxon within the subgenus Euchaetontous. Kisielewski (1997) revised Schwank’s systematics and included the species among the Chaetonotus taxa of unclear subgeneric position. We agree with Kisielewski’s view until the shape of the scales is described.

Lad & Patil (2016) documented a gastrotrich species named Chaetonotus trianguliformis from the brackish water of Bhayander and Naigaon estuary ( Thane , Mumbai, Maharashtra). The species was included in a list of meiofauna taxa, without providing any morphometric details. Considering the type of habitat in which the gastrotrich specimens were found, and the difficult of identifying a gastrotrich species in absence of a full set of cuticular details, we consider this record to be unreliable .