Diacyclops hisuta, Karanovic, Tomislav, Grygier, Mark J. & Lee, Wonchoel, 2013

Karanovic, Tomislav, Grygier, Mark J. & Lee, Wonchoel, 2013, Endemism of subterranean Diacyclops in Korea and Japan, with descriptions of seven new species of the languidoides-group and redescriptions of D. brevifurcus Ishida, 2006 and D. suoensis Ito, 1954 (Crustacea, Copepoda, Cyclopoida), ZooKeys 267, pp. 1-76 : 35

Diacyclops hisuta sp. n.

Diacyclops suoensis Ito - Ueda et al. 1996: p. 309, fig. 4. Synonymy.

Diacyclops languidoides suoensis n. subsp. - Ito 1954: p. 399, Figs 114-148. [non]

Diacyclops languidoides suoensis Ito - Ito 1957: p. 15, Figs 35-48. [non]

Diacyclops suoensis Ito - Lee et al. 2007: p. 162, Figs 7-8; Chang 2009: p. 478, Figs 263-264. [non]

Type locality.

Japan, Yamaguchi prefecture, Mine city, Shuho township, Akiyoshi, Akiyoshido cave, approximately 34°13'N, 131°18'E, stream flowing through the cave.

Type material.

Holotype female (illustrated by Ueda et al. (1996) in their figure 4 A–E) and allotype male (illustrated by Ueda et al. (1996) in their figure 4 F–L), originally deposited at the Nakajima Marine Biological Station, Ehime University, Matsuyama city, Ehime Prefecture, Japan (however, specimens probably destroyed during earthquake in 2001; Prof. Hiroshi Ueda pers. comm.); both collected at the type locality, 13 April 1996, leg. T. Kuramoto. [not examined]

Etymology.

The species name is dedicated to Professors Hiroshi Ueda (formerly Marine Biological Station, Ehime University; currently Usa Marine Biological Station, Kochi University) and Susumu Ohtsuka (Takehara Station, Setouchi Field Science Center, Hiroshima University), and to Dr. Tadashi Kuramoto (Akiyoshi-dai Museum of Natural History), who discovered this population and described it under the name Diacyclops suoensis Ito, 1954 (see Ueda et al. 1996). The name is composed of the first syllables of their given names and should be treated as a Latin noun in apposition.

Description.

Female and male as described in Ueda et al. (1996) from Akiyoshido cave, and illustrated in their figure 4 as Diacyclops suoensis Ito, 1954.

Remarks.

Ueda et al. (1996) stated that they identified the Diacyclops population from Akiyoshido cave as Diacyclops suoensis mainly based on the shape of its seminal receptacle, but they noted four significant morphological differences between their specimens and the two populations described by Ito (1954, 1957). Their decision could have been motivated by the fact that Akiyoshido cave lies only 40 km east-southeast from the type locality of Diacyclops suoensis , and that Diacyclops suoensis was also found much further east by Ito (1957). In our view, the differences already noted by Ueda et al. (1996) justify the erection of a new species. Not only does Diacyclops hisuta sp. n. differ from Diacyclops suoensis in the length of the dorsal caudal setae, proportions of the caudal rami, proportions of the genital double-somite, and size of the innermost terminal caudal setae, but it has all these characters in common with the Korean Diacyclops parasuoensis sp. n. (see above), in addition to slender and very elongated lateral arms of the seminal receptacle. It is quite clear that Diacyclops hisuta and Diacyclops parasuoensis form a sibling species pair, and they can only be distinguished at this stage by the habitus shape (much more slender in Diacyclops parasuoensis ). It is possible that they also differ in the number of inner setae on the second endopodal segment of the first leg, if we assume that Ueda et al. (1996) found the armature formula of the population from Akiyoshido cave to be the same as that reported by Ito (1957). Unfortunately, the description and illustrations provided by Ueda et al. (1996) do not show details of any mouth appendage or the armature of the first three pairs of swimming legs, so many characters cannot be compared.