Eoniphargus kojimai
Creators: name: Tomikawa, Ko
name: Kobayashi, Norio
name: Morino, Hiroshi
name: Mawatari, Shunsuke F.
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Mesogammaridae
Eoniphargus
Eoniphargus kojimai

description: EONIPHARGUS KOJIMAI (UÉNO, 1955) (FIGS 2–6)
Neoniphargus (Eoniphargus) kojimai Uéno, 1955: 148–152, figs 1–3.
Eoniphargus kojimai: Straškraba, 1964: 138; 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.
Materials for SEM observation: One male (4.3 mm) and one female (4.4 mm).
Description: Male, NSMT-Cr 16652. Head (Fig. 2A): 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): 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); primary flagellum with c. 22 articles, each article with 1 aesthetasc (Fig. 3C), calceoli lacking. Antenna 2 (Fig. 3D): 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).
Pereonites 1–7 (Fig. 2A): smooth with fine setae. Pleonites 1–3 (Fig. 2A): smooth with fine setae, dorsal margin with 4 setae (Fig. 5A–C). Coxae: coxae 1–4 with marginal and facial setae, posterior margin of coxa 4 widely excavate (Fig. 4D); anterior lobe of coxae 5–6 dominant (Fig. 4G, J); coxa 7 (Fig. 4M) shallow, 0.5 × as deep as wide. Urosomite 1 (Fig. 5D): dorsal margin with a pair of robust setae. Urosomite 2 (Fig. 5E): dorsal margin with a pair of robust setae and a single robust seta. Urosomite 3 (Fig. 5F): dorsal margin bare.
Upper lip (Fig. 2B): ventral margin rounded, with minute setae. Lower lip (Fig. 2C): inner lobes lacking, outer lobes broad, shoulder rounded. Mandible (Fig. 2D): left and right incisors 5-dentate; left lacinia mobilis 4-dentate (Fig. 2E), right lacinia weakly bifid, 3-dentate (Fig. 2F); 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): inner plate triangular, medial margin with 6 plumose setae; outer plate with 11 robust serrate setae (Fig. 2I); palp article 2 with 5 robust setae and single slender seta apically (Fig. 2J). Maxilla 2 (Fig. 2K): inner plate with 7 plumose facial setae in oblique row. Maxilliped (Fig. 2L): inner plate reaching end of palp article 1, quadrate, with 3 subapical setae and 1 medial robust seta (Fig. 2O); outer plate ovate, reaching middle of palp article 2, with row of robust setae extending from apex along medial margin (Fig. 2N); 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): 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); dactylus curved, posterior margin not serrate. Gnathopod 2 (Fig. 3L): 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); dactylus curved, not serrate.
Pereopod 3–4 (Fig. 4A, D, E): 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). Pereopod 5 (Fig. 4G): 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). Pereopod 6 (Fig. 4J): 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). Pereopod 7 (Fig. 4M): like pereopod 5, except: basis without outer facial setae; merus–dactylus missing.
Pleopods (Fig. 5G, J, K): peduncle longer than rami, with few setae, rami well developed; retinacula paired, without associated setae (Fig. 5H); inner basal margin of inner ramus of pleopods 1–3 with 2 bifid plumose setae (Fig. 5I); inner ramus 7-, outer ramus 8- to 9- articulate. Epimeral plates 1–3 (Fig. 5N–P): weakly pointed posterodistally, lacking ventromarginal setae, posterior margin with no or 1 seta.
Uropod 1 (Fig. 5R): 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): 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): 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); 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): 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): peduncular articles 1, 2 and 3 with length ratios 1.0: 0.8: 0.5; accessory flagellum 4-articulate (Fig. 3G); primary flagellum with c. 23 articules. Antenna 2 (Fig. 3I): 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); right lacinia mobilis 4-dentate, weakly bifid (Fig. 2G). Maxilliped: robust apical setae on inner plate more stiff than those of male (Fig. 2P).
Brood plates: on pereopods 2–5; narrow, lacking brood setae. Pleopods (Fig. 5L, M): peduncles of pleopods 1 and 3 with 3 and 1 setae, respectively.
Uropod 2 (Fig. 5T): 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): 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): as long as wide; cleft 71%.
SEM observation: One male and one female were observed via SEM. Calceolus (Fig. 6A, B), 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) 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).
description: Published as part of 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), pp. 643-670 in Zoological Journal of the Linnean Society 149 (4) on pages 647-652, DOI: 10.1111/j.1096-3642.2007.00277.x, http://zenodo.org/record/4634851