Caenanthura koreana, Song, Ji-Hun & Min, Gi-Sik, 2015

Song, Ji-Hun & Min, Gi-Sik, 2015, Two new species, Caenanthura koreana sp. nov. and Apanthura koreaensis sp. nov. (Crustacea: Isopoda: Anthuridae) from South Korea, Zootaxa 3937 (2), pp. 362-376 : 364-368

publication ID	https://doi.org/ 10.11646/zootaxa.3937.2.7
publication LSID	lsid:zoobank.org:pub:ACDA5FDA-7E8F-49FD-9D71-CA64521FF30D
DOI	https://doi.org/10.5281/zenodo.5622145
persistent identifier	https://treatment.plazi.org/id/3A1787E8-FFD1-AE3E-D185-9987FCC7FCF8
treatment provided by	Plazi
scientific name	Caenanthura koreana
status	sp. nov.

Treatment

Caenanthura koreana View in CoL sp. nov.

( Figs 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Material examined. Holotype (NIBRIV0000307405): Non-ovigerous female ( Fig. 2 View FIGURE 2 A, B), 9.1 mm in length, Namhae Island (34°54´N, 127°50´E), Gyeongsangnam-do, south coast of South Korea, muddy bottoms, depth 2.2 m, collected on 9 May 2007, coll. S. J. Song ( Fig. 1 View FIGURE 1 ).

Paratypes (NIBRIV0000307406–0000307411): 6 females, same sampling location as the holotype. All collected on May 2007, coll. S. J. Song.

Diagnosis. Body elongate and slender, about 11.4 times longer than wide, with no mid-dorsal pits. Rostrum short, as long as anterolateral lobes. Antennular flagellum with 4 articles. Antennal flagellum with 2 articles. Maxillipedal palp with 3 articles; palp articles 2–3 fused, 4–5 fused. Mandibular palp with 2 articles with suture. Pereopods 2–3 similar, carpus triangular. Pereopods 4–7 similar, carpus sub-rectangular. Uropodal endopod about 1.5 times longer than wide; exopod wide, 2.3 times longer than wide. Pleotelson 2.3 times longer than wide.

Description. Female holotype (NIBRIV0000307405): Body ( Fig. 2 View FIGURE 2 A, B) length 9.1 mm, slender, about 11.4 times longer than wide; no setation or mid-dorsal pits. Eyes absent. Cephalon small, 0.9 times as long as wide; rostrum short, as long as anterolateral lobes. Pleon 1.2 times longer than wide, as long as pleotelson, and longer than pereonite 7. Pleonites 1–5 fused.

Antennule ( Fig. 2 View FIGURE 2 C) peduncle with 3 articles. Article 1 laterally with 4 plumose sensory setae; article 2 with 1 long simple seta and 2 plumose sensory setae; article 3 distally with 1 long simple seta and plumose sensory seta; flagellum with 4 articles with respectively 1 long simple seta, 2 simple setae, no setae, 2 simple setae and 3 aesthetascs.

Antenna ( Fig. 2 View FIGURE 2 D) peduncle with 5 articles. Article 2 with 3 simple setae; articles 4 and 5 distolaterally with 1 plumose sensory seta and 4 simple setae. Flagellum with 2 articles (last minute) with numerous setae.

Maxilliped ( Fig. 2 View FIGURE 2 E) palp with 3 articles (1 free; 2–3 fused; 4–5 fused). Article 1 with 1 simple seta; 2–3 fused articles with 1 simple seta, 1.3 times longer than wide; 4–5 fused articles smallest with 5 simple setae, not elongate.

Mandible ( Fig. 2 View FIGURE 2 F) palp with 2 articles distally with 1 simple seta respectively. Article 1 long, approximately 3 times longer than article 2; presence of suture between articles. Incisor with 3 teeth (2 of them small); molar with 2 processes, distally rounded.

Maxilla ( Fig. 2 View FIGURE 2 G) with 4 stout distal teeth.

Pereopod 1 ( Fig. 3 View FIGURE 3 A) robust; basis as long as ischium with 4 simple setae and 2 plumose sensory setae; ischium with 2 simple setae on ventral margin, 4 simple setae on dorsal margin; merus with 7 simple setae on ventral margin, 3 simple setae on dorsal margin; carpus with 2 robust spines and 6 simple setae on ventral margin; propodus swollen, with thick 4 setae, 2 thin setae and 1 strong proximal spiniform seta (about as long as unguis) on palm; unguis much longer than other pereopods.

Pereopod 2 ( Fig. 3 View FIGURE 3 B) basis and ischium subequal; basis with 6 simple setae and 1 plumose sensory seta; ischium with 11 simple setae on ventral margin, 3 simple setae on dorsal margin; merus with 10 simple setae on ventral margin, 3 simple setae on dorsal margin; carpus distoventrally rounded, with 1 sensory spine and 5 simple setae on ventral margin; propodus oval, with 1 short robust spine and 5 simple setae on ventral margin, 1 distal simple seta.

Pereopod 3 ( Fig. 3 View FIGURE 3 C) generally similar to pereopod 2.

Pereopods 4 to 7 ( Fig. 3 View FIGURE 3 D–G) similar, carpus with 1 sensory spine and 3–4 simple setae on ventral margin, 1 plumose sensory seta and simple seta on dorsal margin. Dactylus of pereopod 7 margin by spinules. Unguis of pereopod 2 to 7 small.

Pleopod 1 ( Fig. 4 View FIGURE 4 D) sympod with 5 retinaculae. Exopod 2.6 times longer than wide, surrounded distally and laterally by 33 plumose setae; endopod much slender at about one third of exopod width and slightly shorter than exopod, surrounded distally 12 plumose setae.

Pleopod 2 ( Fig. 4 View FIGURE 4 E) exopod surrounded distally by 13 plumose setae, 1 short plumose seta on lateral margin; endopod surrounded by 8 plumose setae.

Uropodal sympod ( Fig. 4 View FIGURE 4 B) 2.3 times longer than wide, 1.6 times longer than endopod, with 4 plumose setae distomedially and laterally, respectively.

Uropodal endopod ( Fig. 4 View FIGURE 4 B) about 1.5 times longer than wide, distally and laterally about 24 simple setae (17 long and 7 short); medially 3 plumose sensory setae and 3 simple setae. Endopod not extended beyond apex of pleotelson.

Uropodal exopod ( Fig. 4 View FIGURE 4 C) 2.3 times longer than wide, surrounded by about 46 plumose setae. Pleotelson ( Fig. 4 View FIGURE 4 A) 2.3 times longer than wide, with 2 basal statocysts; apex with 2 pairs of simple setae; dorsally with 4 long simple setae.

Variation. Paratypes (NIBRIV0000307406–0000307411): General body shapes similar; body length: 7.8–9.3 mm; the first article 2.8–3.3 times longer than second one on mandibular palp; pleotelson wide, 2.2–2.3 times longer than wide; uropod exopod, 2.1–2.4 times longer than wide; and the endopod 2.9–3.2 times wider than exopod on first pleopod.

Molecular data. A 528 base pairs of CO1 sequence (GenBank accession number: KP225160 View Materials ) was obtained from one individual of C. koreana sp. nov. (NIBRIV0000307405). Sequence alignment did not contain any insertion or deletion. No stop codon was found during amino acid translation with invertebrate mitochondrial code.

Distribution. Caenanthura koreana sp. nov. is known only from the southern coast of the Korean Peninsula.

Etymology. The specific name ‘ koreana ’ is derived from the name of the nation from which the specimens were collected.

Remarks. Caenanthura koreana sp. nov. differs from previously reported species of Caenanthura in the following unique combination of characteristics: a presence of suture on mandibular palp articles, first article three times longer than second; maxillipedal palp articles 2–3 fused, 4–5 fused; uropodal exopod wide, 2.3 times longer than wide. Caenanthura koreana sp. nov. is most similar to C. gutui ( Negoescu, 1997) , with regard to features related to external appearance. These two species are similar in the following characteristics: (1) the general shape of the antennule and antenna; and (2) the general shape of the pereopods. The new species, however, differs from C. gutui in (1) the total body length; (2) ratio of the first and second articles of the mandibular palp; (3) ratio of the length and width on the pleotelson and exopod of the uropod, respectively; and (4) ratio of the endopod and exopod width of the first pleopod. In C. gutui , the body size of non-ovigerous females ranges from 4.8 to 5.9 mm; the first article on the mandibular palp is twice as long as the second article; the pleotelson and exopod of the uropod is 2.8 times longer than wide, respectively; and the endopod is two times wider than the exopod on the first pleopod. In comparison, in the new species, the body size of non-ovigerous females ranges from 7.8 to 9.1 mm; the first article on the mandibular palp is three times longer than the second article; pleotelson and exopod of the uropod is 2.3 times longer than wide, respectively; and the endopod is three times wider than the exopod on the first pleopod (see the Table 1 View TABLE 1 and the key to the species of Caenanthura ).