Chaetonotus (Hystricochaetonotus) hystrix Mečnikow, 1865

Figs 14–15

Chaetonotus hystrix Mečnikow, 1865: 451, fig. 7.

Locus typicus

Russia.

Material examined

POLAND • 21 adults, 3 subadults, 7 juveniles; Kraków, Botanical Garden, Jubilee Greenhouse, sites 1–3; 50°03'38" N, 19°57'30" E; 17 Apr. 2014; M. Kolicka leg.; NHC (photomicrographs, also in the author’s collection) .

Distribution

Chaetonotus (Hystricochaetonotus) hystrix Mečnikow, 1865 is considered a cosmopolitan and common species recorded worldwide from highly differing habitats (lakes with different trophic structures, mountain springs, fertile ponds, peat bogs, brackish estuarine waters) (Kisielewski 1991). Outside Europe, it is known from Brazil (Kisielewski 1991), Israel (Kisielewski 1997b), Japan (Saito 1937) and Paraguay (Daday 1905).

Remarks

The specimens examined here correspond very well with the original description (Figs 14–15). All their morphometric characteristics are within the ranges given in the literature for this species (Rudescu 1967; Roszczak 1969; Balsamo 1983; Schwank 1990; Kisielewski 1984, 1997b). The total body length of adult specimens varied from 107.4 to 128.6 μm; length of pharynx was between 27.6 and 32.7 μm; length of intestine from 56.1 to 81.9 μm; there were 15–17 total longitudinal rows of scales (5–7D +2DL+2L+4LV+ 2V), with 13–17 scales in the central row. The total body length of juvenile specimens varied from 86.9 to 105.4 μm; length of pharynx was between 28.6 and 32.4 μm; length of intestine from 37.9 to 52.6 μm; there were 13–17 total longitudinal rows of scales (5–7D +2DL+2L+2–4LV+ 2V), with 13–17 scales in the central row. Among the adults, two had a large, developing egg, while one had an X-organ and two packages of sperm.