Eoniphargus iwataorum, Shintani & Lee & Tomikawa, 2022
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publication ID |
https://dx.doi.org/10.3897/subtbiol.44.86914 |
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publication LSID |
lsid:zoobank.org:pub:1865B081-1072-4900-BFC7-563C0D29DA7D |
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persistent identifier |
https://treatment.plazi.org/id/4234A07E-026A-4DB1-A2E8-2DE845E6295E |
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taxon LSID |
lsid:zoobank.org:act:4234A07E-026A-4DB1-A2E8-2DE845E6295E |
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treatment provided by |
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scientific name |
Eoniphargus iwataorum |
| status |
sp. nov. |
Eoniphargus iwataorum sp. nov.
Figs 6 View Figure 6 , 7 View Figure 7 , 8 New Japanese name: Iwata-chikayokoebi View Figure 8
Type material.
Holotype: ♀ 5.6 mm (NSMT-Cr 30782), Sabi River (36.898181°N, 140.012153°E), Imaizumi, Ohtawara, Tochigi Prefecture, Japan, collected by Y. Iwata on 27 January 2019. Paratype: ♀ 5.3 mm (NSMT-Cr 30783; G1751), ♀ 6.0 mm (NSMT-Cr 30784), data same as for the holotype.
Diagnosis.
Urosomite 3 without dorsal setae. Epimeral plates 2-3 each with ventral robust seta. Peduncular article 1 of antenna 1 with robust seta on posterodistal corner. Antenna 2 with peduncular article 2 gland cone not exceeding end of article 3. Mandible with 5-dentate left incisor; left lacinia mobilis 4-dentate, right one bifid with many teeth. Inner plate of maxilla 1 with eight plumose setae. Inner plate of maxilla 2 with seven facial seta in oblique row. Peduncle of pleopod 3 with seta. Uropod 1 with peduncle bearing basofacial robust setae. Uropod 3 with inner ramus 0.25 times as long as outer ramus; outer ramus 2-ariticulate, with plumose setae on medial margin. Telson almost as long as width, cleft for 67% of length.
Etymology.
The specific epithet was derived from the names of Mr. Yasuyuki Iwata and Mr. Tomofumi Iwata, who collected the specimens of this new species.
Description.
Female holotype, NSMT-Cr 30782. Head (Fig. 6A View Figure 6 ) as long as pereonites 1 and 2 combined; eyes absent; inferior antennal sinus distinct with rounded angle. Dorsal margins of pleonites 1-3 (Fig. 6B-D View Figure 6 ) each with four setae. Posterodistal corners of epimeral plates 1-3 (Fig. 6E-G View Figure 6 ) weakly produced; ventral margin of epimeral plate 1 without setae, epimeral plates 2 and 3 each with ventral robust seta; posterior margins of epimeral plates 1-3 each with two setae. Dorsal margin of urosomite 1 (Fig. 6H View Figure 6 ) with slender setae; urosomite 2 (Fig. 6I View Figure 6 ) with dorsal robust setae; urosomite 3 (Fig. 6J View Figure 6 ) without dorsal setae.
Antenna 1 (Fig. 6K View Figure 6 ) length 0.25 times as long as body; length ratio of peduncular articles 1-3 in 1.0: 0.8: 0.4; posterodistal corner of peduncular article 1 with robust seta; accessory flagellum 4-articulate; primary flagellum 27-articulate. Antenna 2 (Fig. 6L View Figure 6 ) length 0.7 times as long as antenna 1; peduncular article 4 slightly shorter than article 5; flagellum 22-articulate; calceoli absent.
Upper lip (Fig. 6M View Figure 6 ) with rounded apical margin bearing fine setae. Mandibles (Fig. 6N-P View Figure 6 ) with left and right incisors comprising five and six teeth, respectively; left lacinia mobilis comprising four teeth, right lacinia mobilis bifid with many teeth; molar process triturative with plumose seta; length ratio of palp articles 1-3 in 1.0: 2.0: 1.5; palp article 1 without setae; palp article 2 with eight marginal setae; palp article 3 with pair of A-setae, several D-setae and E-setae, lateral face with fine setae. Lower lip (Fig. 6Q View Figure 6 ) lacking inner lobes; outer lobes broad, shoulder rounded, with fine setae. Maxilla 1 (Fig. 6R, S View Figure 6 ) with elliptical inner lobe, bearing eight plumose setae on medial margin; outer plate rectangular, with 11 serrate robust setae apically; palp 2-articulate, article 1 without setae, article 2 with five robust setae and slender plumose seta apically. Maxilla 2 (Fig. 6T View Figure 6 ) with inner plate bearing seven plumose setae in oblique row. Maxilliped (Fig. 7A-C View Figure 7 ) with inner plate exceeding end of palp article 1, subquadrate, bearing three subapical robust setae and medial robust seta; outer plate ovate, reaching middle of palp article 2, with row of robust setae along apical to medial margins; palp 4-articulate, article 2 longest with medial setae, nail of article 4 distinct.
Gnathopod 1 (Fig. 7D, E View Figure 7 ) with subquadrate coxa bearing setae along anterior to ventral margins; anterior and posterior margins of basis with long setae; carpus length 0.9 times as long as length of propodus and 1.4 times width of carpus; propodus length 1.7 times width, palmar margin weakly serrate, oblique, with three medial and one lateral robust setae; dactylus reaching posterodistal corner of propodus. Gnathopod 2 (Fig. 7F, G View Figure 7 ) with coxa expanded proximally bearing setae along anterior to ventral margins; posterior margin of basis with long setae; carpus length 1.2 times as long as length of propodus and 2.8 times width of carpus; propodus length 2.2 times width, palmar margin weakly serrate, almost vertical, with two medial and two lateral robust setae; dactylus reaching posterodistal corner of propodus.
Pereopod 3 (Fig. 7H, I View Figure 7 ) with subquadrate coxa, proximally expanded, bearing setae along anterior to ventral margins; posterior margin of basis with long setae. Pereopod 4 (Fig. 7J View Figure 7 ) with coxa bearing setae along anterior to ventral margins, posteroproximally concave; posterior margin of basis with long setae. Pereopod 5 (Fig. 7K View Figure 7 ) with bilobed coxa bearing seta on posterior lobe; anterior margin of basis with robust setae, posterodistal corner weakly lobate. Pereopod 6 (Fig. 7L View Figure 7 ) with bilobed coxa bearing seta on anterior and posterior lobes; basis with robust setae on anterior margin, posterodistal corner weakly lobate. Pereopod 7 (Fig. 8A-C View Figure 8 ) with elliptical basis bearing robust setae on anterior margin, posterodistal corner weakly lobate.
Coxal gills (Fig. 8D, E View Figure 8 ) ovate with stalks on gnathopod 2 and pereopods 3-6.
Pleopods 1-3 (Fig. 8F-I View Figure 8 ) with peduncles longer than rami, bearing distal seta on pleopods 1 and 2 and proximal seta on pleopod 3; retinacula paired (Fig. 8I View Figure 8 ); mediobasal margin of inner ramus with bifid plumose setae; rami well developed.
Uropod 1 (Fig. 8J View Figure 8 ) with peduncle bearing three basofacial robust setae and dorsal robust setae; inner ramus length 0.7 times as long as peduncle, with two medial and one lateral robust setae, and ventroproximal seta; outer ramus length 0.9 times as long as inner ramus, with two robust setae on medial margin. Uropod 2 (Fig. 8K View Figure 8 ) with peduncle bearing dorsal robust setae; inner ramus as long as peduncle, bearing two medial robust setae and ventroproximal slender seta; outer ramus length 0.7 times as long as inner ramus, without marginal setae. Uropod 3 (Fig. 8L View Figure 8 ) with peduncle length 0.3 times as long as outer ramus, bearing robust setae on distal edge; inner ramus length 0.2 times as long as outer ramus, with seta on medial margin; outer ramus 2-articulate, proximal article with plumose setae on medial margin and robust setae on medial and lateral margins, terminal article length 0.2 times as long as proximal article with subapical setae.
Telson (Fig. 8M View Figure 8 ) length slightly shorter than wide, each lobe with two lateral and three apical robust setae and two dorsolateral penicillate setae, cleft for 67%.
Distribution and environment.
The species is known only from its type locality in the Sabi River, Tochigi Prefecture, Japan.
Remarks.
Eoniphargus iwataorum sp. nov. is similar to E. kojimai but differs from the latter in the following features (features of E. kojimai in parentheses): urosomite 3 without robust setae on dorsal margin (bearing robust setae), maxilla 2 with inner plate bearing seven setae in oblique row (nine setae), and uropod 2 without robust seta on lateral margin of outer ramus (bearing robust seta).
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