Chaetonotus (Primochaetus) heideri Brehm, 1917

Krishnan, Sreerag, Ghosh, Arnab, Bharti, Daizy, Todaro, M. Antonio & Kumar, Santosh, 2023, First record of Chaetonotus (Primochaetus) heideri (Gastrotricha, Chaetonotida) from India, Records of the Zoological Survey of India 123 (3), pp. 255-260 : 256-258

Chaetonotus (Primochaetus) heideri Brehm, 1917 ( Figure 1 A-F, 2A-G, 3A-B)

Diagnosis of the Indian population of Chaetonotus (Primochaetus) heideri Brehm, 1917 : The individuals from India exhibit a bottle-to-ten-pin shape with a three-lobed head. On average, the dimensions of the Indian specimens are as follows: body length = 170 μm, body maximum width = 50 μm, head width = 40 μm, mouth diameter = 10 μm, pharynx length = 45 μm, pharynx width = 15 μm, adhesive tube length = 20 μm, posterior-dorsal scale length = 11 μm, egg length = 28 μm, Egg width = 11 μm. The body is flexible, and the cuticle is covered in scales and spines, which extend over the entire animal. The scales exhibit an anterior double edge, characteristic of the taxon, with dorsal spines increasing in length from the anterior to the posterior end. The spines become barbed approximately at the near-middle portion of each spine. The posterior end is furcated, and each furcal branch terminates with a thin adhesive tube. Posteriormost spines are parallel to the adhesive tubes and do not exceed the length of the tubes.

Occurrence: India- (present study); Elsewhere: The species is thus far reported from U.S.A. ( Emberton, 1980), Italy ( Balsamo & Fregni, 1995), Sweden ( Kånneby et al., 2009, 2013), Brazil ( Garraffoni et al., 2010; Kånneby et al., 2013), Canada, France, Germany, Great Britain, Romania, Russia ( Schwank, 1990; Kånneby, 2013), Poland ( Kolicka et al., 2013, 2020), Ukraine ( Trokhymchuk, 2020).

Remarks: New record to Indian waters.

Figures

Figure 1. Photomicrographs ofChaetonotus (Primochaetus) heideri from live specimens. A-C. Specimens show the body shape and body flexibility. D. Enlarged view of the pharynx, arrowhead indicates a sensory ciliary tuft. E. Detailed view of the oral opening and sensory ciliary tufts (arrowheads). F. Posterior portion of a specimen with a thin adhesive tube. AT, adhesive tube; I, intestine; M, mouth; P, pharynx; PJ, pharyngeal junction. Scale bars: 40 μm (D, E) and 50 μm (A-C).