Niphargus kermanshahi, Esmaeili-Rineh, Somayeh, Heidari, Firoozeh, Fišer, Cene & Akmali, Vahid, 2016

Esmaeili-Rineh, Somayeh, Heidari, Firoozeh, Fišer, Cene & Akmali, Vahid, 2016, Description of new endemic species of the genus Niphargus Schiödte, 1849 (Amphipoda: Niphargidae) from a karst spring in Zagros Mountains in Iran, Zootaxa 4126 (3), pp. 338-350 : 340-347

Niphargus kermanshahi sp. nov.

( Figures 2–6 )

Material examined and type locality. Holotype, Male specimen (12 mm) from Kangarshah spring, Sahneh city, Kermanshah province, Iran, coordinates (N 34◦36'53.7", E 47◦39'44.2"). Specimens collected by Firoozeh Heidari & Vahid Akmali; 17 May 2014. Samples are stored under catalogue number ZCRU Amph.1023.

Diagnosis. Urosomites 1–2 each with three simple setae along the dorso-median surface. Urosomite 2 with two robust setae dorso-laterally. Epimeral plates not produced. Telson deeply clefted, each lobe with three apical robust setae, one marginal robust seta and two plumose setae. Palpus of maxilla 1 short, not reaching the tip of outer lobe. Propods of gnathopods 2 broader than long, slightly subrounded. Propodus of gnathopods 2 with two short subcorner R-robust setae (so called supporting robust setae) in palmar corner. Inner ramus of uropod 1 shorter of outer ramus.

Description of holotype. Total length 12 mm. Body strong and stout. Head length 16% of body length ( Figure 2 ).

Antennae 1 ( Figure 3 A). Antenna 1 is 0.43 of body length. Peduncular articles 1–3 progressively shorter; length of peduncular article 3 exceeds one half of peduncular article 2 (ratio 1: 1.72); main flagellum with 25 articles (most of which with short setae), accessory flagellum biarticulated and reaching 1/3 of article 4 of main flagellum; both articles with one and two simple setae, respectively ( Figure 3 A).

Antennae 2 ( Figure 3 B). Length ratio antenna 1: 2 as 1: 0.36. Peduncular article 4 as long as article 5, articles 4 and 5 with nine and seven groups of simple setae, respectively; flagellum with 10 articles. Length of flagellum: length of peduncle article 4 + 5 as 1: 1.46.

Labium ( Figure 4 F) with inner lobes and fine setae on the tip of outer lobes.

Maxilla 1 ( Figure 3 D-E). Inner plate with two long simple setae; outer plate with seven uni-, bi-, pluri or without lateral projections; palp biarticulated, short and does not reach the tip of outer lobe, with three long distal simple setae.

Maxilla 2 ( Figure 4 E). Both plates with numerous long distal simple setae, inner lobe with two lateral simple setae.

Mandibular palp ( Figure 3 H). Ratio of mandibular palp articles 1: 2: 3 as 1: 1.86: 2.26. The proximal article has no setae, the second article with eight setae along inner margin and the third article with one group of three Asetae, three groups of B-setae, no C-setae, 15 D-setae and five E-setae.

Left mandible ( Figure 3 F). Incisor with five teeth, lacinia mobilis with four teeth; seven setae with lateral projections between lacinia and triturative molar.

Right mandible ( Figure 3 G). Incisor with four teeth, lacinia mobilis pluritooth; six setae with lateral projections between lacinia and triturative molar.

Maxilliped ( Figure 4 G). Inner plate short, with four distal robust setae intermixed with seven distal simple setae and four simple long lateral setae subdistally; outer plate exceeding more than half of posterior margin of palp article 2, with 12 robust setae along inner margin and four simple setae distally; palp article 3 at outer margin with two proximal and one inner and outer groups of long simple setae; palp of terminal article each with one simple seta in outer and inner margins, respectively. Nail shorter than pedestal.

Gnathopod 1 ( Figure 4 A–B). Coxa of gnathopod 1 same long as gnathopod 2. Coxa trapezoid, broader than long, ventral and anterior margins each with four simple setae; basis with setae on anterior and posterior margins; ischium and merus with posterior group of setae. Carpus with one group of setae anterodistally, a bulge with long simple setae; carpus 0.48 of basis length and 0.77 of propodus length. Propodus slightly longer than broad, posterior margin with five transverse rows of setae; anterior margin with three setae in two groups in addition to anterodistal group of six simple setae; palm slightly convex, defined on outer surface by one strong long corner Srobust seta accompanied laterally by two L-robust setae with lateral projections and a row of three facial M-setae, on inner surface by one short subcorner R-robust seta. Dactylus reaching posterior margin of propodus, outer and inner margins with a row of three and five simple setae, respectively, nail short, 0.29 of total dactylus length.

Gnathopod 2 ( Figure 4 C–D). Coxa 2 slightly trapezoid, with six setae along antero-ventral margin; basis with groups and single setae distributed along anterior and posterior margins, posterior margin of ischium and merus with one posterior group of setae. Carpus 0.53 of basis length and 0.72 propodus length. Carpus with evenly distributed simple setae posteriorly and a single group of four setae anterodistally. Propodus in gnathopod 2 larger than gnathopod 1, trapezoid shape and broader than long, posterior margin with five rows of transverse setae, anterior margin with 10 setae in two groups in addition to anterodistal group of six simple setae, palm nearly convex, defined on outer surface by one strong long corner S-robust seta accompanied laterally by two L-robust setae with lateral projections and a row of three facial M-setae, on inner surface by two short subcorner R-robust setae. Dactylus reaching posterior margin of propodus, outer and inner margins of dactylus with three and five simple setae, respectively. Nail length 0.33 of total dactylus length.

Coxae 3–7 ( Figure 5 A–E). Length to width ratio in coxa 3 as 1: 1.27, with 11 antero-ventro-posterior simple setae. Length to width ratio in coxa 4 as 1.7: 1, with nine antero-ventro-posterior simple setae, posterior concavity shallow and approximately 0.1 of coxa width ( Figure 5 A–B). Coxa 5 with anteriorly developed lobe, with four and one simple setae in anterior and posterior lobes, respectively. Coxa 6 with anteriorly developed lobe, with two simple setae in anterior lobe, with two robust and two simple setae in posterior lobe. Coxa 7 of half-elliptic shape and a single simple seta ( Figure 5 C–E).

Pereopods 3–7 ( Figure 5 A–E). Pereopod 3 shorter than 4 with length ratio of 1: 1.13 ( Figure 5 A–B); dactylus short, with one robust seta at the base of the nail at inner margin of each of pereopods 3–4, length of dactylus 0.41 of propodus in pereopod 4. Nail shorter than pedestal ( Figure 5 B).

Pereopods 5: 6: 7 length ratios, 1: 1.21: 1.63, respectively. Pereopod 7 is 0.5 of body length. Pereopod bases 5– 7 respectively with six, nine and eight simple setae along posterior margins and five, six and six groups of robust setae along anterior margins ( Figure 5 C–E).

Ventro-anterior and ventro-posterior lobe of ischium in pereopods 5–7 developed. Ischium, merus and carpus in pereopods 5–7 with several groups of robust and simple setae along anterior and posterior margins; propodus of pereopod 7 longer than these in 5–6, dactyli of pereopods 5–7 with one robust and one short simple seta at the base of nail at inner margin, dactylus of pereopod 7 with one simple seta in outer margin, nail length of pereopod 7 is 0.27 of total dactylus length ( Figure 5 C–E).

Pereonites 1–6. No setae.

Pereonite 7. With single simple seta postero-ventrally.

Pleonites 1–3. With two simple setae along the entire dorsal surface.

Epimeral plates 1–3 ( Figure 6 G). Postero-ventral corner angular but not produced, posterior and ventral margins of plates 1–3 slightly to distinctly convex. Postero-ventral corner of plates 1 and 3 each with one robust seta and one simple seta; plate 2 with two robust setae and one simple seta postero-ventrally. Ventral margin of plates 2–3 with three and four robust setae, respectively.

Pleopods 1–3 ( Figure 6 A–C). Peduncle of pleopod 1 with one simple seta and two-hooked retinacles at distal part of inner margin ( Figure 6 A); peduncle of pleopod 2 with one robust seta in dorsomedial surface, two simple setae and two-hooked retinacles at distal part of inner margin; peduncle of pleopod 3 with one simple seta at distal part of outer margin, and two-hooked retinacles at distal part of inner margin, rami of pleopods 1–3 each with 10– 12 articles ( Figure 6 A–C).

Urosomites 1 and 2 ( Figure 2 ). Dorso-median surface with three simple setae per somite; urosomite 2 with two robust setae dorso-laterally.

Urosomite 3 ( Figure 2 ). No setae.

Uropods 1–3 ( Figure 6 D–F). Uropod 1 peduncle with six and three large robust setae along dorsolateral and dorsomedial margins, respectively. Ratio of inner to outer ramus length 1: 1.05. Inner ramus with five groups of single robust setae laterally and five robust setae distally. Outer ramus with four groups of six robust setae laterally and five robust setae distally ( Figure 6 D). Outer ramus in uropod 2 longer than inner, both rami with lateral and distal long robust setae ( Figure 6 E). Uropod 3 long, almost 0.25 of body length. Peduncle of uropod 3 with five robust setae and one simple seta distally. Second to first article ratio of outer ramus 1: 2.01; first article of outer ramus with five and six groups of robust and setae along inner and outer margins, respectively ( Figure 6 F); distal article with marginal simple setae and six simple setae distally; inner ramus short, with one distal robust seta.

Telson ( Figure 6 H). Two times as long as broad, lobes slightly narrowing, each with three robust setae and one simple seta distally, and with one long robust seta and two plumose setae marginally.

Etymology. The name “ kermanshahi ” refers to Kermanshah province that found samples.

Phylogenetic position of the newly described species. Niphargus kermanshahi is nested within the Iranian clade and shares an ancestor with recently described N. bisitunicus ( Figure 7 ). Four individuals of newly described species constitute a strongly supported monophylum that differs from N. bisitunicus in 0.07% of base pairs based on Kimura two parameter distance. According to study of Hou & Li (2010), this is within the same range of divergence for 28S gene as in well-defined Gammarus species. Hence, in addition to morphological characters, molecular data indicate that this population deserves independent species status. As the two species resemble each other in some diagnostic traits, we revised also the diagnosis of N. bisitunicus .

Revised diagnosis of N. bisitunicus Esmaeili-Rineh et al. 2015

Urosomites 1–2 with one and three robust setae accompanied with two simple setae along the dorso-lateral margin. Epimeral plates distinctly produced. Telson deeply cleft, each lobe with three apical robust setae, one marginal robust seta and two marginal simple setae. Palpus of maxilla 1 normally long, and exceeds the tip of robust setae on outer lobes of maxilla 1. The shape of propods of gnathopods 1–2 is rectangular, propods tend to be longer than broad. Propods of gnathopods 1–2 each with two short subcorner R-robust setae (so called supporting robust setae). Dactyli of pereopods 3–7 with one simple seta at outer margin. Inner ramus of uropod 1 shorter of outer ramus.

Figures

FIGURE 2. Niphargus kermanshahi sp. nov., holotype, lateral view. Specimen collected from Kangarshah spring.

FIGURE 3. Niphargus kermanshahi sp. nov., male 12 mm (holotype, ZCRU Amph. 1023). (A) Antenna I; (B) Antenna II; (C) Head; (D – E) Maxilla I; (F) Left mandible; (G) Right mandible; (H) Mandibular palp. Scale bars: 1 = 0.25 mm (F – G); 2 = 0.5 mm (C – E, H); 3 = 1 mm (A – B).

FIGURE 4. Niphargus kermanshahi sp. nov., male 12 mm (holotype, ZCRU Amph. 1023). (A – B) Gnathopod I; (C – D) Gnathopod II; (E) Maxilla II; (F) Labium; (G) Maxilliped. Scale bars: 1 = 0.5 mm (E – G); 2 = 1 mm (A – D).

FIGURE 5. Niphargus kermanshahi sp. nov., male 12 mm (holotype, ZCRU Amph. 1023). (A) Pereopod III; (B) Pereopod IV; (C) Pereopod V; (D) Pereopod VI; (E) Pereopod VII. Scale bars: 1 mm (A – E).

FIGURE 6. Niphargus kermanshahi sp. nov., male 12 mm (holotype, ZCRU Amph. 1023). (A) Pleopod I; (B) Pleopod II; (C) Pleopod III; (D) Uropod I; (E) Uropod II; (F) Uropod III; (G) Epimeral plates; (H) Telson. Scale bars: 1 = 0.5 mm (G – H); 2 = 1 mm (A – E); 3 = 2 mm (F).

FIGURE 7. Bayesian consensus tree of 58 Niphargus taxa (54 taxa from Esmaeili-Rineh et al. 2015), based on the 28 S ribosomal DNA sequences. Species are identified and named according to the taxonomic description. Posterior probabilities are indicated on main branches.