Leydigia (Neoleydigia) acanthocercoides Fischer 1854
Creators: name: Kotov, Alexey A.
name: Jeong, Hyun Gi
name: Lee, Wonchoel
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Diplostraca
Leydigia
Leydigia acanthocercoides

description: 18. Leydigia (Neoleydigia) acanthocercoides (Fischer, 1854)
Fig. 24
Synonymy. Lynceus acanthocercoides Fischer, 1854, p. 431–433, Pl. 3: Figs 21–25.
Leydigia acanthocercoides (Fischer) in Lilljeborg 1901, p. 499–502, Pl. 71: Figs 4–8; Smirnov 1971, p. 458–460, Figs 569–570 (only Europe!); Flössner 1972, p. 327–329, Fig. 154; Flössner 2000, p. 355–357, Fig. 131A–G; Kotov et al. 2003, p. 196, Figs 86–90; Kotov, 2009, p. 48–53, Fig. 224–261.
See extensive synonymy in Kotov (2009).
Type locality. Fischer’s material was from "stehenden Wässern der Insel Madeira, als auch in solchen bei Iwanofskoje in Gouvernment Tambow" (Fischer 1854), the latter is in European Russia.
Locality in Korea. 8 (see Fig. 1 and Table 1).
Parthenogenetic female. Body triangular-ovoid, dorsal margin slightly and uniformly curved from tip of rostrum to smooth postero-dorsal angle; posterior margin convex (Fig. 24 A). Coarse striation non-distinct, fine striation very distinct, see Kotov 2009. Head small, compound eye small, ocellus slightly larger (Fig. 24 B). Three large head pores on area devoid of reticulation. Labral keel widely-triangular-ovoid, with distinct apex, its anterior margin with fringe of long setules, 4–5 lateral groups of fine setules. In anterior portion of the ventral margin setae longer (Fig. 24 C). On posterior margin, a row of setules on inner side of valve, located far from margin, they are larger that 'setules' of marginal membrane (see Kotov 2009). Postabdomen broad, subovoid, robust, preanal margin shorter than anus, with 3 relatively large projections in basal 2/3, preanal and postanal angles well defined, no distal margin and no dorso-distal angle (fig. 24D). Postanal marginal denticles in numerous clusters, size increasing distally in each cluster, 10–12 fascicles of stout lateral setae, decreasing in size basally, 3–4 setae in each fascicle on distal portion, only 2 setae in each fascicle in middle. Postabdominal claw slightly shorter than preanal plus anal portion of postabdomen, slightly curved, basal spine rudimentary or absent (Fig. 24 E). Antenna I not reaching tip of rostrum, with 4 transverse rows of setules at anterior face and series of short setules at tip. Sensory seta arising about 1/4 of way from tip. Largest aesthetasc less than half length of appendage. Antenna II with few stout spinelike setules on first and second endopod segments; a strong spine on proximal segment of exopod longer that the next segment (Fig. 24 F). Distal lateral seta short, basal lateral seta as long as apical seta. Limbs as described by Kotov (2009). Size in our material 0.6 mm.
Notes. Leydigia acanthocercoides differs from L. ciliata Gauthier, 1939 in (1) relatively wide postabdomen and (2) predominantly doubled, not tripled, lateral setae of the middle portion of postanal margin. The latter is a tropical-subtropical species (Kotov et al. 2003) also present in Korean Peninsula and well illustrated by Yoon & Kim (1993) and Yoon (2010). The status of Asian " L. ciliata " needs to be checked, because Sinev & Sanoamuang (2011) revealed some differences in male morphology between Asian and African populations.
About L. acanthacercoides Kotov (2009) mentioned that “At present I can confirm the presence of this species only in Europe and northern Asian Russia ('Siberia')”. The acanthocercoides -group needs to be revised. Recently Kotov & Alonso (2010) demonstrated that in the Iberian Peninsula there are two species earlier identified as “ L. acanthocercoides ” (i.e. in Alonso, 1996). Our superficial examination of a single Korean population did not reveal any differences from the European populations. So, Korea might be the most southern limit of L. acanthocercoides’ distribution. Among specimens illustrated from China under different names L. acanthocercoides was not found, but L. ciliata is present (Chiang & Du 1979, Fig. 139–140, 142).
description: Published as part of 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 *, pp. 50-90 in Zootaxa 3368 on pages 80-81, DOI: 10.5281/zenodo.214313