Chaetonotus (Hystricochaetonotus) octonarius Stokes, 1887

Chatterjee, Tapas & Todaro, M. Antonio, 2021, An annotated checklist of the chaetonotidan Gastrotricha from India, Zootaxa 5027 (3), pp. 332-350 : 337

Chaetonotus (Hystricochaetonotus) octonarius Stokes, 1887

Records from India. ANDHRA PRADESH: Visakhapatnam – Rao & Mohan (1987); WEST BENGAL: Achipur in South 24 Parganas District— Sharma (1980); GENERAL RECORD: Naidu & Rao (2004), Purushothaman (2017).

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

Distribution. Cosmopolitan.

Remarks. Small sized species, characterized by eight strong, single barbed spines (22-28 μm in length), origi- nating at mid-posterior trunk from suboval scales. Spines are arranged in three columns and three transverse rows having 3, 2, 3 spines respectively. The Indian specimens agree quite well with the description of the species, with the exception perhaps of arrangement of the spines, which are reported by Sharma (1980) to be arranged in four transverse rows (i.e., 3+2+2+1). Considering that in chaetonotid Gastrotricha usually the medial spines appear to be slightly misplaced with respect to adjacent, lateral ones, we view the difference reported for the Indian specimens to be a misinterpretation. On the other hand, in the drawing of the species made by Sharma (1980), the medial spine of the first row is sketched anterior to the lateral ones and not in line with them (see Sharma 1980, page 266, Fig. 4).