Chydorus irinae Smirnov & Sheveleva, 2010

Kotov, Alexey A., Jeong, Hyun Gi & Lee, Wonchoel, 2012, Cladocera (Crustacea: Branchiopoda) of the south-east of the Korean Peninsula, with twenty new records for Korea *, Zootaxa 3368, pp. 50-90 : 71-72

12. Chydorus irinae Smirnov & Sheveleva, 2010

Fig. 17

Synonymy. Chydorus irinae Smirnov & Sheveleva, 2010 , p. 635–637, Figs 1–2; Kotov et al. 2011a, p. 406.

Type locality. "Mouth of the Tom' River" ( Smirnov & Sheveleva 2010), Amur Area, Russia.

Locality in Korea. 6a (see Fig. 1 and Table 1 ).

Parthenogenetic female. In lateral view, body very high, “humped”, as Smirnov & Sheveleva (2010) ( Fig. 17 A). Body with strong lateral outgrowths in level of brood pouch ( Fig. 17 B), in anterior view these “wings” rounded-triangle in adults ( Fig. 17 C) and acute in juveniles ( Fig. 17 K). Dorsal head pores typical for the genus ( Fig. 17 D–E). Labral keel relatively small, with a rounded apex ( Fig. 17 F). In anterior portion of valve there is an inner flap-like projection ( Fig. 17 G); reticulation on valves as polygons with rounded angles and undulated edges. In posterior half of ventral margin, setae remarkable submarginally; in posterior portion of valves there are successive series of fine setules ( Fig. 17 H–I). Postabdomen elongated, ventral margin concave, preanal margin concave, preanal angle strongly projected, anal margin concave, postanal margin straight, dorso-distal angle widely rounded, distal margin short, postabdominal claw located on a massive projection ( Fig. 17 J). Postanal teeth thin, singular, present on postanal and anal margin; lateral setules longer in distal portion. Postabdominal claw with two basal spines, a strong distal basal spine (about 0.3 of claw length) and a short proximal spine (more than two times shorter than distal spine). Antenna I with 9 terminal aesthetascs. Antenna II as in Chydorus sphaericus . Limbs were not studied. Size in our material 0.31–0.37 mm.

Notes. We found only a single adult and a single juvenile female, not sufficient for a full redescription. Smirnov & Sheveleva (2010) mentioned that in anterior view, the body is “triangular, with maximum width dorsally to the middle height”. We found that it is widened dorsally, forming lateral projections as Disparalona ikarus or Monospilus daedalus . Previously C. irinae was known only from a single locality in the Amur basin. Now it is obvious that its range is wider. Unfortunately, it is impossible to associate any previous descriptions and illustrations from the Far East with this taxon due to a “tradition” to study specimens only in lateral view. This taxon seems to be an endemic of the Far East.

Figures

FIGURE 17. Chydorus irinae Smirnov & Sheveleva, 2010, parthenogenetic female from Bak Sil Ji 1, locality 6 a: A – C, adult, lateral, ventral and anterior view; D – E, dorsal head pores; F, labrum; G, anterior portion of valve; H – I, postero-ventral portion of valve, inner view; J, postabdomen; K, juvenile, anterior view. Scale bars: 0.1 mm.