Heteroxenotrichula subterranea ( Remane, 1934 )

Chatterjee, Tapas & Todaro, M. Antonio, 2021, An annotated checklist of the chaetonotidan Gastrotricha from India, Zootaxa 5027 (3), pp. 332-350 : 344-345

Heteroxenotrichula subterranea ( Remane, 1934)

Records from India. ANDHRA PRADESH: Visakhapatnam (Waltair), Bhimlipatnam— Ganapati & Rao (1967), Sarma & Mohan (1981); GENERAL RECORD: Naidu & Rao (2004).

Habitat (as in Indian records). Marine, intertidal; fine and medium sands, 20 cm below surface near mid-water level.

Distribution. Originally described from North Europe, the species was subsequently reported from the Mediterranean Sea, Somalia and India (Bay of Bengal). According to Hummon (2010) the species is also present along the Pacific coast the USA.

Remarks. In India the species has been found at least twice; however, morphometric data were provided only once, by Ganapati & Rao (1967), who state that the Indian specimens conform to the original description. However, by comparing morphometric parameters of the specimens from the Baltic (original description by Remane, 1934) and India, the Indian specimens appear slightly larger in body length (160-180 μm vs 130-150 μm), they bear a longer pharynx (50 μm vs 40 μm) and a shorter furca (40 μm vs 47 μm). On the other hand, the Mediterranean specimens are larger for body (180-222 μm) and furca (55-67 μm) length (see Ruppert 1979). In our opinion the highlighted differences among populations suggest another possible case of species lumping, and call for additional analyses to support the current hypothesis that the different populations belong to the same species. In the meantime, the presence of H. subterranea in India should be considered only provisional.