Heterolepidoderma acidophilum Kånneby et al., 2012

Kolicka, Małgorzata, Kisielewski, Jacek, Nesteruk, Teresa & Zawierucha, Krzysztof, 2013, Gastrotricha from the Poznań Palm House — one new subgenus and three new species of freshwater Chaetonotida (Gastrotricha), Zootaxa 3717 (2), pp. 231-279 : 269

Heterolepidoderma acidophilum Kånneby et al., 2012 ( Table 15)

Synonym: Heterolepidoderma ocellatum var. sphagnophilum Kisielewski, 1981

Locality: Site 2; session III.

Material: 1 sample, 1 adult specimen, photographed.

Remarks: The specimen found in the Poznań Palm House corresponds well with the morphological features from the original description and redescription of this species (Kisielewski 1981; Kånneby et al. 2012). However, this specimen does not have a pair of ocular granules and shows differences in morphometry, such as a slightly greater body length (135 Μm vs 103–133 Μm), and shorter adhesive tubes (6.1 Μm vs 8–9 Μm). Additionally, the total number of longitudinal rows of scales is higher (24 scales vs 20–23 scales), therefore the ratio of scale distribution is different (92.3% vs 121–200%).

The presence or lack of ocellar granule is a useful feature (Kisielewski 1981), but this structure has been also reported to be either present or absent in different populations of the same species (e.g. Heterolepidoderma ocellatum (Mečnikow, 1865)) (Fregni et al. 1998; Schwank 1990). However, it follows the morphological data presented by Kisielewski (1981) and Kånneby et al. (2012) well, and is considered to be Heterolepidoderma acidophilum Kånneby et al., 2012 .

Distribution: Previously recorded as Heterolepidoderma ocellatum var. sphagnophilum in Poland (Kisielewski 1981) and Russia (Tretjakova 1989), and in Sweden as Heterolepidoderma acidophilum by Kånneby et al. (2012).