Eoniphargus kojimai, (UENO, 1955)

Tomikawa, Ko, Kobayashi, Norio, Morino, Hiroshi & Mawatari, Shunsuke F., 2007, New gammaroid family, genera and species from subterranean waters of Japan, and their phylogenetic relationships (Crustacea: Amphipoda), Zoological Journal of the Linnean Society 149 (4), pp. 643-670 : 647-652

publication ID	https://doi.org/ 10.1111/j.1096-3642.2007.00277.x
publication LSID	lsid:zoobank.org:pub:E58C6912-18DC-4D8A-903D-E9EAC01A79FA
DOI	https://doi.org/10.5281/zenodo.5114046
persistent identifier	https://treatment.plazi.org/id/D92D3636-4A35-FFE8-7094-FDB3FA05DE64
treatment provided by	Carolina
scientific name	Eoniphargus kojimai
status

Treatment

EONIPHARGUS KOJIMAI ( UÉNO, 1955) View in CoL ( FIGS 2–6 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 )

Neoniphargus (Eoniphargus) kojimai Uéno, 1955: 148–152 , figs 1–3.

Eoniphargus kojimai: Straškraba, 1964: 138 View in CoL ; Straškraba, 1967: 127; Bousfield, 1977: 301; Barnard & Barnard, 1983: 581–582.

Material examined: Male, 4.3 mm (appendages on slides and carcass in ethanol), NSMT-Cr 16652 and two females, 4.6 mm, 4.3 mm (appendages on slides and carcass in ethanol), NSMT-Cr 16653–16654, from 20 cm depth on the bank of the Seto River (34°52′50″N, 138°13′08″E), Terajima , Fujieda City , Shizuoka Prefecture, 3.xi.2004, collected by T. Torii GoogleMaps .

Materials for SEM observation: One male (4.3 mm) and one female (4.4 mm).

Description: Male, NSMT-Cr 16652. Head ( Fig. 2A View Figure 2 ): as long as pereonites 1 and 2 combined; inferior antennal sinus deep with rounded angle; eyes absent; rostrum short; lateral cephalic lobe rounded. Antenna 1 ( Fig. 3A View Figure 3 ): length 0.6 × body length; peduncular articles 1, 2 and 3 with length ratios 1.0: 0.8: 0.4; article 1 shorter than head length, posterodistal part with robust seta; articles 1–3 with lateral and medial setae; accessory flagellum 3-articulate ( Fig. 3B View Figure 3 ); primary flagellum with c. 22 articles, each article with 1 aesthetasc ( Fig. 3C View Figure 3 ), calceoli lacking. Antenna 2 ( Fig. 3D View Figure 3 ): length 0.6 × length of antenna 1; peduncular articles 4–5 with lateral and medial setae; length of article 4 reaching 90% of length of article 5; article 5 of right antenna 2 with 2 calceoli; article 5 of left antenna 2 lacking calceoli; flagellum 16-articulate, articles with calceoli ( Fig. 3E View Figure 3 ).

Pereonites 1–7 ( Fig. 2A View Figure 2 ): smooth with fine setae. Pleonites 1–3 ( Fig. 2A View Figure 2 ): smooth with fine setae, dorsal margin with 4 setae ( Fig. 5A–C View Figure 5 ). Coxae: coxae 1–4 with marginal and facial setae, posterior margin of coxa 4 widely excavate ( Fig. 4D View Figure 4 ); anterior lobe of coxae 5–6 dominant ( Fig. 4G, J View Figure 4 ); coxa 7 ( Fig. 4M View Figure 4 ) shallow, 0.5 × as deep as wide. Urosomite 1 ( Fig. 5D View Figure 5 ): dorsal margin with a pair of robust setae. Urosomite 2 ( Fig. 5E View Figure 5 ): dorsal margin with a pair of robust setae and a single robust seta. Urosomite 3 ( Fig. 5F View Figure 5 ): dorsal margin bare.

Upper lip ( Fig. 2B View Figure 2 ): ventral margin rounded, with minute setae. Lower lip ( Fig. 2C View Figure 2 ): inner lobes lacking, outer lobes broad, shoulder rounded. Mandible ( Fig. 2D View Figure 2 ): left and right incisors 5-dentate; left lacinia mobilis 4-dentate ( Fig. 2E View Figure 2 ), right lacinia weakly bifid, 3-dentate ( Fig. 2F View Figure 2 ); molar strong, triturative, with single plumose seta; palp articles 1, 2 and 3 with length rations 1.0: 2.4: 1.9; article 1 unarmed; article 2 with 8 marginal setae; article 3 with pair of A-setae, many D- setae and E-setae, outer face with fine setae. Maxilla 1 ( Fig. 2H View Figure 2 ): inner plate triangular, medial margin with 6 plumose setae; outer plate with 11 robust serrate setae ( Fig. 2I View Figure 2 ); palp article 2 with 5 robust setae and single slender seta apically ( Fig. 2J View Figure 2 ). Maxilla 2 ( Fig. 2K View Figure 2 ): inner plate with 7 plumose facial setae in oblique row. Maxilliped ( Fig. 2L View Figure 2 ): inner plate reaching end of palp article 1, quadrate, with 3 subapical setae and 1 medial robust seta ( Fig. 2O View Figure 2 ); outer plate ovate, reaching middle of palp article 2, with row of robust setae extending from apex along medial margin ( Fig. 2N View Figure 2 ); palp article 2 long, length 2.1 × length of article 1 and 1.8 × length of article 3; articles 2 and 3 medially setose; article 3 with rugose apical lobe.

Gnathopods: dissimilar in size and form. Gnathopod 1 ( Fig. 3J View Figure 3 ): anterior and posterior margins of basis with long setae; ischium and merus short, ventral margin of merus setose; length of carpus 0.9 × length of propodus, not lobate, with medial setae, ventral margin lined with setae; propodus rectangular, palm lined with small triangular protuberances, 3 inner and 2 outer robust setae ( Fig. 3K View Figure 3 ); dactylus curved, posterior margin not serrate. Gnathopod 2 ( Fig. 3L View Figure 3 ): posterior margin of basis with long setae; carpus long, length 1.2 × length of propodus, not lobate, with medial setae, ventral margin lined with setae; propodus more slender than gnathopod 1 propodus, palm lined with small triangular protuberances, 2 inner and 2 outer robust setae ( Fig. 3M View Figure 3 ); dactylus curved, not serrate.

Pereopod 3–4 ( Fig. 4A, D, E View Figure 4 ): slender, posterior margin of basis with long setae; ischium short, almost as long as wide; merus, carpus and propodus with length ratios 1.0: 0.8: 0.8, with short setae marginally; length of dactylus 0.4 × length of propodus, anteroproximal and posterior margins with setae ( Fig. 4B View Figure 4 ). Pereopod 5 ( Fig. 4G View Figure 4 ): anterior margin of basis with robust setae, posterior margin with fine setae, outer face with few setae, posteroventral lobe rounded; ischium short, shorter than wide; merus, carpus and propodus with length ratios 1.0: 1.2: 1.3; dactylus slender, length 0.3 × length of propodus, with 2 setae ( Fig. 4H View Figure 4 ). Pereopod 6 ( Fig. 4J View Figure 4 ): like pereopod 5, except: outer face of basis without setae; merus, carpus and propodus with length ratios 1.0: 1.1: 1.4; length of dactylus 0.2 × length of propodus ( Fig. 4K View Figure 4 ). Pereopod 7 ( Fig. 4M View Figure 4 ): like pereopod 5, except: basis without outer facial setae; merus–dactylus missing.

Pleopods ( Fig. 5G, J, K View Figure 5 ): peduncle longer than rami, with few setae, rami well developed; retinacula paired, without associated setae ( Fig. 5H View Figure 5 ); inner basal margin of inner ramus of pleopods 1–3 with 2 bifid plumose setae ( Fig. 5I View Figure 5 ); inner ramus 7-, outer ramus 8- to 9- articulate. Epimeral plates 1–3 ( Fig. 5N–P View Figure 5 ): weakly pointed posterodistally, lacking ventromarginal setae, posterior margin with no or 1 seta.

Uropod 1 ( Fig. 5R View Figure 5 ): length of peduncle 1.5 × length of inner ramus, peduncle with robust setae on dorsolateral and dorsomedial margins, basofacial margin with 3 robust setae; length of outer ramus 0.8 × length of inner ramus, inner margin with 2 robust setae, outer margin bare; inner and outer margins of inner ramus with 1 and 2 robust setae, respectively. Uropod 2 ( Fig. 5S View Figure 5 ): length of peduncle 1.2 × length of inner ramus, with robust setae on dorsolateral and dorsomedial margins, outer distal corner with modified seta; length of outer ramus 0.6 × length of inner ramus, margin bare; inner basal margin of inner ramus with pair of slender setae, outer margin with 2 robust setae. Uropod 3 ( Fig. 5U View Figure 5 ): length of peduncle 0.3 × length of outer ramus, with robust setae, distal edge fringed with robust bent setae; inner ramus short, length 0.3 × length of outer ramus, with robust setae; outer ramus 2-articulate, terminal article distinct, length 0.3 × length of proximal article ( Fig. 5V View Figure 5 ); inner margin of proximal article with a pair of setae and 3 single robust setae, accompanied by 4 plumose setae; outer margin of proximal article with 2 clusters and 1 pair of robust setae, single robust seta, and a few simple slender setae. Telson ( Fig. 5X View Figure 5 ): length 1.1 × basal maximum width, dorsolateral margins with 2 robust setae and 2 penicillate setae dorsolaterally, and 3 robust setae apically; cleft 67%.

Female, NSMT-Cr 16653. Antenna 1 ( Fig. 3F View Figure 3 ): peduncular articles 1, 2 and 3 with length ratios 1.0: 0.8: 0.5; accessory flagellum 4-articulate ( Fig. 3G View Figure 3 ); primary flagellum with c. 23 articules. Antenna 2 ( Fig. 3I View Figure 3 ): length of peduncular article 4 reaching 90% of length of article 5, article 5 lacking calceoli; flagellum 16-articulate, calceoli lacking.

Coxae: facial setae on coxae 1–5 denser than those of male.

Mandible: right incisor 6-dentate ( Fig. 2G View Figure 2 ); right lacinia mobilis 4-dentate, weakly bifid ( Fig. 2G View Figure 2 ). Maxilliped: robust apical setae on inner plate more stiff than those of male ( Fig. 2P View Figure 2 ).

Brood plates: on pereopods 2–5; narrow, lacking brood setae. Pleopods ( Fig. 5L, M View Figure 5 ): peduncles of pleopods 1 and 3 with 3 and 1 setae, respectively.

Uropod 2 ( Fig. 5T View Figure 5 ): peduncle about as long as inner ramus, outer distal corner with robust simple seta; length of outer ramus 0.8 × length of inner ramus, with robust inner marginal seta; inner and outer margins of inner ramus with 1 and 2 robust setae, respectively. Uropod 3 ( Fig. 5W View Figure 5 ): distal edge of peduncle fringed with robust setae; inner ramus with robust seta; length of terminal article of outer ramus 0.2 × length of proximal article, inner margin of proximal article with 3 pairs of robust setae, single robust seta, 4 plumose setae, and a few simple setae, outer margin of proximal article with 2 clusters and 2 pairs of robust setae and a few slender simple setae. Telson ( Fig. 5Y View Figure 5 ): as long as wide; cleft 71%.

SEM observation: One male and one female were observed via SEM. Calceolus ( Fig. 6A, B View Figure 6 ), stalk and bulla well developed, concavity of proximal element shallow, distal element with 12–16 well-defined transverse bands. Molar of right mandible ( Fig. 6C, D View Figure 6 ) strong, tritulative.

Remarks: Our specimens agree well with Uéno’s (1955) original description of E. kojimai , except for two characters. Although our Shizuoka specimens have two articulations on the outer ramus of the uropod 3, Uéno described only one articulation based on his material from Tokyo. However, Uéno (1955: figs 3– 7) illustrated a notch on the outer ramus of the uropod 3, also noted by Barnard & Barnard (1983), indicating his specimens also had two articles. Our specimens have 11 setae on the outer plate of the maxilla 1, whereas Uéno (1955) described ‘the outer plate of the maxilla 1 with 10 robust apical setae’. We failed to resolve this discrepancy, since we could not access the type material of E. kojimai , which may be lost.

Eoniphargus kojimai is distinguished from E. glandulatus by the following characters ( E. glandulatus in parentheses): the antennal sinus is deep (very shallow); the male antenna 2 has calceoli (lacking); the gland cone of the antenna 2 reaches distal end of the peduncular article 3 of the antenna 2 (exceeds article 3); the lacinia mobilis on the left mandible is 4-dentate (5-dentate), the peduncle of the uropod 1 has robust basofacial setae (lacking); the outer ramus of the uropod 3 is 2-articulate (uniarticulate); and the telson is 1.1 times as long as wide (1.4 times).