Niphargus yasujensis, Bargrizaneh & Fišer & Esmaeili-Rineh, 2021

Bargrizaneh, Zeinab, Fišer, Cene & Esmaeili-Rineh, Somayeh, 2021, Groundwater amphipods of the genus Niphargus Schiødte, 1834 in Boyer-Ahmad region (Iran) with description of two new species, Zoosystema 43 (7), pp. 127-144 : 131-137

Niphargus yasujensis n. sp.

( Figs 3-6 )

urn:lsid:zoobank.org:act:CB0F33E9-7970-427D-8263-FF29D577F00A

MATERIAL EXAMINED. — Holotype. Iran • ♂ adult (7 mm); Biareh Spring , Sisakht City, Kohgiloyeh and Boyer Ahmad Province; 30°51’N, 51°27’E; Zeinab Bargrizaneh leg.; 5.IV.2015; ZCRU Amph.1053 . Paratypes. Iran • 2 ♂; same data as for holotype; ZCRU Amph.1053 .

DIAGNOSIS. — A slender Niphargus species with elongated body. Pleonites with two setae along the dorso-posterior margin of each segment and with one strong spine at base of uropod I. Epimeral plates II-III slightly produced, posterior and ventral margins concave and convex, respectively. Antenna I shorter than half of the total body length. Outer lobe of maxilla I with seven spines with 0-3 lateral projection. Palpus of maxilla I short and not reaching the tip of the outer lobe ( Fig. 3C, D ). Gnathopods propodi of trapezoidal to rectangular shape ( Fig. 4A, B ). Propodus of gnathopod I with two equal palmar spines ( Fig. 4A ). Length of carpus and propodus of gnathopod I equal. Pereopods shorter than half of total body length, with one spine at the nail base. Outer ramus of uropod I slightly longer than inner ramus.Telson lobes with five distal spines each ( Fig. 6H ). Female unknown.

DIAGNOSTIC COI SEQUENCES. — GeneBank Accession Numbers: MT636103 - MT636106 .

ETYMOLOGY. — The name “yasujensis’” refers to Yasuj City, the center of Kohgiloyeh and Boyer-Ahmad province ( Iran), where the species was found.

DESCRIPTION OF HOLOTYPE

Measurements

Total male body length: 7 mm. Head length representing 18% of total body length.

Antenna I ( Fig. 3A )

40% of total body length. Peduncular articles 1-3 progressively shorter; length of peduncular article 2 more than half of peduncular article 3; most flagellum articles with one short aesthetasc. Main flagellum with 21 articles, most of which with short setae. Accessory flagellum bi-articulated, reaching beyond two-third of article 4 of main flagellum; distal article with three setae.

Antenna II ( Fig. 3B )

Almost half of the length of antenna I. Peduncular articles 4:5 ratio equal to 1.36: 1; peduncle articles 4 and 5 each with nine groups of simple setae. Flagellum of antenna II 0.89% of the length of peduncle articles 4 + 5, totalling eight articles.

Mouth parts ( Figs 3 , 4 )

Labium ( Fig. 4C ). Bilobate; with developed inner lobes.

Left mandible ( Fig. 3E ). With five teeth on incisor process, with two teeth on lacinia mobilis and a row of seven serrated setae.

Right mandible ( Fig. 3F ). With four teeth on incisor process, with five teeth on lacinia mobilis and a row of five serrated setae.

Mandibular palp ( Fig. 3G ). Ratio of mandibular palp articles 1: 2: 3 equal to 1: 1.72: 2.06. Proximal article without setae; middle article with three simple setae medially; distal article with one A-group of two setae, two single separate Bsetae, no C-setae, ten D-setae and five E-setae.

Maxilla I ( Fig. 3C, D ). With two apical setae on distal palp article, inner plate with two apical setae, outer plate with seven long spines with 3-2-1-1-1-0-0 lateral projections; palp biarticulated, not reaching mid-length of spines on lateral lobe.

Maxilla II ( Fig. 4E ). With inner lobe shorter than outer lobe; both lobes with numerous long apical setae.

Maxilliped ( Fig. 4D ). With three distal spines intermixed with seven distal setae on inner plate; outer plate exceeding proximal half of the palp article 2, with eleven marginal spines and three distal setae; palp article 3 at outer margin with one proximal and one distal group of long setae; palp terminal article with four setae in outer and inner margins, nail shorter than pedestal.

Gnathopod I ( Fig. 4A ). With rhomboid coxal plate, broader than long, with five marginal setae. Posterior and anterior margins of basis armed with single setae and groups of setae; posterior margin of ischium and merus with one posterior group of setae. Carpus length 60% of basis length and 93% of propodus length; anterior carpal margin with four antero-distal setae; carpus with posterior rows of setae on the proximo-posterior bulb and with a long row of setae along postero-medial margin. Propodus trapeozoid, slightly broader than long, anterior margin with one group of four setae in addition to four antero-distal setae. Posterior margin with three rows of setae. Palm convex, palmar corner with two strong palmar spines of equal length, three inner short accompanying spines and one outer denticulate spine. Dactylus reaching posterior margin of propodus, outer and inner margins of dactylus with one and three setae, respectively. Nail length 42% of total dactylus length.

Gnathopod II ( Fig. 4B ). With ovoid coxal plate wider than high, with five setae on antero-ventral margin. Basis armed with single setae along posterior and anterior margins. Ischium and merus with one posterior group of setae each. Carpus length 63% of basis length and as long as propodus length; anterior margin with single antero-distal group of setae; carpus with posterior rows of setae on the proximo-posterior bulb and with long row of setae along postero-medial margin. Propodus of gnathopod II longer than broad. Propodus of rectangular shape, anterior margin straight; palm and posterior margins slightly convex. Anterior margin with one group of two setae in addition to antero-distal group of five setae. Palmar corner with one strong long palmar spine and one short accompanying spine on inner surface, with one denticulate spine on outer surface. Dactylus reaching posterior margin of propodus, outer and inner margins with one and four setae, respectively; nail 45% of total dactylus length.

Coxae III-VII

Coxal plate III ( Fig. 5A ) with quadratic shape. Ventral margin with five setae. Coxal plate IV ( Fig. 5B ) rhomboid, depth: width ratio 1.22: 1.00. Antero-ventro-posterior margins with six setae. Coxal plate IV posteriorly slightly concave. Coxal plates V-VI ( Fig. 5C, D ) with anterior lobe; anterior and posterior lobes of coxal plate V each with two marginal setae; coxal plate of VI with two and one setae on anterior and posterior lobes, respectively. Coxal plate VII ( Fig. 5E ) without lobe, with single seta posteriorly.

Pereopods III-IV ( Fig. 5 )

Pereopod III ( Fig. 5A, B ) longer than pereopod IV (pereopod III length: pereopod IV length ratio 1.00: 0.95); dactyli of pereopods III-IV short, with one seta at outer margin in pereopods III-IV; nail length half of dactylus length in pereopod IV. Pereopods V-VII ( Fig. 5 C-E): Pereopods V:VI:VII length ratios as 1: 1.11: 1.12. Pereopod VII 48% of body length. Bases in pereopods V-VI with seven groups of spines along anterior margin each and with nine short setae along posterior margin each. Basis in pereopod VII with seven groups of spines along anterior margin and with eight short setae along posterior margin. Postero-ventral lobe of basis in pereopods V-VII slightly developed. Ischium, merus and carpus in pereopods V-VII with several groups of spines and setae along anterior and posterior margins; propodus of pereopod VII longer than propodus of V-VI, dactyli of pereopods V-VII similar to dactyli of pereopods III-IV with one seta at outer margin, robust seta at the base of nail; nail VII 28% of total dactylus length.

Pereonites

Pereonites I-VII with no setae.

Pleopods I-III ( Fig. 6 A-C)

Peduncle of pleopods I-III with two hooked retinacles; peduncle of pleopod III with two setae along the inner margin, rami of pleopods I-III with six to ten articles per ramus.

Pleonites I-III, each pleonite with two setae along the dorsoposterior margin.

Epimeral plates ( Fig. 6G )

Epimeral plates I-III with pointed postero-ventral angles, posterior and ventral margins concave and convex, respectively. Posterior margins of plates I-III with two, three, and three setae, respectively; ventral margins of plates II-III each with three spines.

Uropods ( Fig. 6 D-F)

Uropod I ( Fig. 6D ) peduncle with five and two spines along dorso-lateral and dorso-medial margins, respectively. Outer ramus slightly longer than inner ramus (ratio as 1.11: 1.00). Inner ramus with three spines laterally and five spines and setae distally. Outer ramus with three groups of spines laterally and five spines distally.A single strong spine at the base of uropod I. Inner ramus in uropod II ( Fig. 6E ) slightly shorter than outer, both rami with lateral and distal long robust setae. uropod III ( Fig. 6F ) almost 20% of body length. Peduncle of uropod III with four distal spines. Proximal article of outer ramus with five and four groups of spines and setae along outer and inner margins, respectively. Distal article of outer ramus 30% proximal article. Distal article with marginal and distal setae. Inner ramus with one spine and seta distally and one seta laterally.

Urosomites I-III

Urosomites I and II postero-dorso-laterally with one and three spines, respectively. Urosomites II with additional posterodorso-lateral seta. Urosomite III without setae.

Telson ( Fig. 6H )

Longer than broad, lobes slightly narrowing apically, each lobe with five distal long spines; lateral margins with one spine and one plumose seta each.

Female

Unknown.

REMARKS

Niphargus yasujensis n. sp. is diagnosed exclusively by a combination of some characters including the presence of two subequal palmar spines on propodi of gnathopod I ( Fig. 4A ) and five apical spines in each telson lobe ( Fig. 6H ). Double palmar spines have been observed in N. hosseiniei Esmaeili-Rineh, Sari, Fišer & Bargrizaneh, 2017 from Iran which has triangular propodi of gnathopods (Esmaeili-Rineh et al. 2015b), in contrast to N. yasujensis n. sp., which has trapezoid to rectangular propodi. Also, the lengths of size carpus and propodus in gnathopod I are similar, a trait not found among Iranian species so far. An additional and potentially unique trait among Iranian species are the five apical spines on the telson lobe in Niphargus yasujensis n. sp. ( Fig. 6H ). Elevated number of spines per telson lobe has been noted in Europe (e.g. N. podogoricensis S. Karaman, 1934 ; N. kusceri S. Karaman, 1950 ) but not in combination with double palmar spines. By contrast, most of Iranian species have three distal spines per telson lobe.To our knowledge only N. daniali Esmaeili-Rineh & Sari 2013 and N. kurdistanensis Mamaghani-Shishvan, Esmaeili-Rineh & Fišer 2017 have four distal spines per lobe.

Figures

FIG. 3. — Niphargus yasujensis n. sp., male 7 mm (holotype, ZCRU Amph. 1053): A, antenna I; B, antenna II; C, D, maxilla I; E, left mandible; F, right mandible; G, mandibular palp. Scale bars: A, B, 1 mm; C, D, H, 0.5 mm; E, F, 0.25 mm;.

FIG. 4. — Niphargus yasujensis n. sp., male 7 mm (holotype, ZCRU Amph. 1053): A, gnathopod I; B, gnathopod II; C, labium; D, maxilliped; E, maxilla II. Scale bars: A, B, 1 mm; C-E, 0.5 mm.

FIG. 5. — Niphargus yasujensis n. sp., male 7 mm (holotype, ZCRU Amph.1053): A, pereopod III; B, pereopod IV; C, pereopod V; D, pereopod VI; E, pereopod VII. Scale bar: 1 mm.

FIG. 6. — Niphargus yasujensis n. sp., male 7 mm (holotype,ZCRU Amph. 1053): 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: A-E, 1 mm; F, 2 mm; G-H, 0.5 mm.