Aspidiophorus squamulosus ( Roszczak, 1936 )

Kånneby, Tobias, 2011, New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden, Zootaxa 3115, pp. 29-55 : 35-36

Aspidiophorus squamulosus ( Roszczak, 1936)

( Figure 4 )

Localities. Gravel pit, Åhus, Skåne (N 55º 55’ 43’’; E 14º 15’ 08’’).

Material. 1 specimen. TL, 208 µm; FL, 21 µm; AL, 10–11 µm; PhL, 50 µm; MD, 15 µm; DC, 28; DR, 43; VC, ~12; TS, 4 x 4 µm; PL 0.5–1 µm.

A large sized species with five-lobed head. Hypostomium well developed as a transverse cuticular bar. The dorsal scales are rhomboidal in shape. Three pairs of simple straight spines are present dorsally at the base of each furcal branch. In the Swedish specimen the middle spine is the shortest, which is in contrast to Roszczak (1969) and Schwank (1990) but in accordance with Kisielewski (1986). Moreover, the number of dorsal scale columns is approximately 28, which is in contrast to Schwank (1990) who states that there are 12–15 dorsal columns. This may be explained by the extremely compressed state under which the Swedish specimen was recorded. However, the total number of columns (including ventrolateral) are 45 and in accordance with Polish specimens found by Kisielewski (1986). The posterior trunk region is covered by apparently non-pedunculated keeled scales. In the caudal bifurcation some of these scales can be seen to carry short spines, perhaps corresponding to the bristles reported by Kisielewski (1986). Ventral interciliary area covered by alternating rows of keels. Ventral ciliation in two longitudinal bands; whether they merge on the head could not be seen. Pharynx, with cuticular reinforcements ( Figure 4 B), widens towards the pharyngeal intestinal junction.

Previously reported from Denmark ( Grilli et al. 2010), Italy ( Balsamo & Tongiorgi 1995), Poland ( Kisielewski 1998) and Sweden ( Kånneby et al. 2009).

Figures

FIGURE 4. Aspidiophorus squamulosus. A) Habitus. B) Pharynx with cuticular reinforcements. C) Dorsal view of the furcal base showing distribution of scales and spines. Scale bars: A, 50 µm; B, 20 µm; C, 10 µm.