Niphargus primoricus Marin & Palatov, 2025, sp. nov.

Niphargus primoricus sp. nov. Figs 2, 3, 4, 5, 6, 7, 8 Material examined. • Holotype, ♂ (bl. 8.0 mm) (ZMMU Mb-1299) – Russian Federation, Krasnodar Kray, Sochi urban district, Khostinskiy district, hyporhean zone of the Khosta River within the boundaries of the Khosta village, 43°30'55.3"N, 39°52'10.1"E, coll. I. Marin & D. Palatov, 23.10.2024. • Paratypes, ♂ (bl. 8.0 mm), ♀ (bl. 7.0 mm) (ZMMU Mb–1300) – Russian Federation, Krasnodar Kray, Sochi urban district, Khostinskiy district, hyporhean zone of the mouth of the Khosta River within the boundaries of the Khosta village, 43°30'33.9"N, 39°52'07.0"E, coll. I. Marin & D. Palatov, 23.10.2024. Additional material. • 3 ♂♂, 7 ♀♀ (LEMMI) – same data and locality as holotype; • 3 ♂♂, 2 ♀♀ – Russian Federation, Krasnodar Kray, Gelendzhik urban district, Golubaya Bukhta (Blue Bay), 44°34'35.9"N, 37°58'48.3"E, pebble beach near the mouth of Ashamba River, in coastal pebble, coll. I. Marin, 12.07.2023; • 2 ♂♂, 3 ♀♀ (bl. 7.0 mm) (LEMMI) – Russian Federation, Krasnodar Kray, Gelendzhik urban okrug, hyporhean zone of the mouth of the Betta River within the boundaries of the Betta village, 44°22'16.67"N, 38°23'48.84"E, coll. I. Marin & D. Palatov, 12.06.2024; • 3 ♀♀ – Russian Federation, Krasnodar Kray, Tuapse district, hyporheic zone of the mouth of the Agoy River within the boundaries of the Agoy village, 44°08'06.75"N, 39°01'33.5"E, coll. I. Marin & D. Palatov, 07.06.2024; • 1 ♂, 6 ♀♀ – Russian Federation, Krasnodar Kray, Tuapse district, hyporhean zone of the mouth of the Nebug River within the boundaries of the Nebug settlement, 44°09'41.6"N, 38°59'52.4"E, coll. I. Marin & D. Palatov, 07.06.2024; • 4 ♀♀ – Russian Federation, Krasnodar Kray, Tuapse district, Nechepsukho River in the Novomikhaylovsky village, under the pedestrian bridge, 44°14'52.24"N, 38°50'35.37"E, coll. I. Marin & D. Palatov, 08.06.2024; • 2 ♂♂, 3 ♀♀ – Russian Federation, Krasnodar Kray, Tuapse district, hyporhean zone of the Agoy River within the boundaries of the village of Agoy, 43°57'45.8"N, 39°16'04.3"E, coll. D. Palatov, 14.07.2020; • 1 ♂, 6 ♀♀ – Russian Federation, Krasnodar Kray, Tuapse district, pebble beaches in the valley of the Tu River near its mouth in the Olginka village, 44°11'28.12"N, 38°53'05.52"E, coll. I. Marin & D. Palatov, 08.06.2024; • 2 ♀♀ (LEMMI) – Russian Federation, Krasnodar Kray, Tuapse district, hyporhean zone of the mouth of the Dederkoy River upstream from the Dederkoy village, 44°04'00.4"N, 39°08'22.8"E, coll. I. Marin & D. Palatov, 13.05.2019; • 4 ♀♀ – Russian Federation, Krasnodar Kray, Sochi urban district, Lazarevsky district, Makopse River under the railway bridge, near the river mouth, 43°59'34.11"N, 39°12'37.98"E, coll. I. Marin & D. Palatov, 06.06.2024; • 1 ♀ – Russian Federation, Krasnodar Kray, Sochi urban district, Lazarevsky district, Kuapse River near the Nizhnyaya Mamedka village, 43°57'10.72"N, 39°18'43.1"E, coll. I. Marin & D. Palatov, 05.06.2024; • 2 ♀♀ – Russian Federation, Krasnodar Kray, Sochi urban district, Lazarevsky district, Ashe River mouth, 43°57'28.8"N, 39°15'41.1"E, coll. I. Marin & D. Palatov, 05.06.2024; • 3 ♂♂, 12 ♀♀ – Russian Federation, Krasnodar Kray, Sochi urban district, Khostinskiy district, hyporhean zone of the mouth of the Khosta River within the boundaries of the Khosta village, 43°30'33.9"N, 39°52'07.0"E, coll. I. Marin & D. Palatov, 15.05.2019; • 3 ♀♀ – Russian Federation, Krasnodar Kray, Sochi urban district, Lazarevsky district, Psezuapse River near the Lazarevskoye village, 200 m upstream from the mouth, 43°53'57.35"N, 39°20'03.97"E, coll. I. Marin & D. Palatov, 03.06.2024. Diagnosis. Head with small yellow pigmented spots on anterior lobe. Posteroventral corners of epimeral plates I – III bluntly rounded. Urosomite I unarmed; urosomite II with one simple seta on each side dorsolaterally; urosomite II with two strong spines on each side dorsolaterally. Propodus of gnathopods I and II subtrapezoidal, with its width shorter than depth; dactylus with numerous simple setae along outer margin. Dactyli of pereopods III – VII with one small additional median spine and one median short plumose seta at outer margin. Rami of uropod I unequal in size: endopodite ~ 1.8 × longer than exopodite in mature males, and 1.2–1.25 × longer than exopodite in small males and females, with tufts of well-seen long curved setae in both sexes; exopodite of uropod III differ in males and females, significantly longer in males. Pleopods with two hooks in retinacles. Telson with two, three, or four medium-sized distal spines on each lobe and one or two lateral spines, accompanied by two small plumose setae, and its dorsal surface with none or one small or medium submarginal spine on each side and none or one small mesial seta. Description (based on holotype male, ZMMU Mb-1299). Body depigmented, stygomorphic, moderately slender (see Fig. 2). Head (Fig. 2 B): length is ~ 7.5 % of body length; rostrum and pigmented spots on anterior lobe absent, with bluntly produced anteroventral lobes and excavated anteroventral sinus. Eyes cornea absent, but small pigmented yellow spots well seen on head (Fig. 2 B). Pereon: pereonites I – VII without setae, smooth. Pleosoma: pleonites I – III with several short marginal setae on each posterodorsal margin. Epimeral plates (Fig. 7 A, C, E). Posteroventral corners of epimeral plates I and II rounded (Fig. 7 A, C), epimeral plate III with posteroventral corner posteriorly produced, nearly right-angled (Fig. 7 E). Epimeral plate I (Fig. 7 A): posterior margin convex, ventral margin slightly convex; without spines along ventral margin; with eight setae along posterior margin; posteroventral angle with one strong seta. Epimeral plate II (Fig. 7 C): posterior and ventral margin convex; with two spiniform setae along ventral margin; eight setae along posterior margin, one of which strong and close to posteroventral angle; posteroventral angle with one strong seta. Epimeral plate III (Fig. 7 E): posterior margin almost straight slightly convex, ventral margin slightly convex; with three spiniform setae along ventral margin; with eight setae along posterior margin; posteroventral angle with one strong seta. Urosomites (Fig. 8 B, D): urosomite I with one long simple seta on each side dorsolaterally, with one posteroventral long spine-like near basis of uropod I; urosomite II with two simple strong spines each side dorsolaterally; urosomite III unarmed. Coxae: coxal plate I (Fig. 5 D) oval in shape, with rounded anteroventral margin, armed with 11 setae, width / depth ratio 1 / 1.3; coxal plate II (Fig. 5 G) close to quadrate, with rounded anteroventral margin, armed with 8 setae, width / depth ratio ~ 1 / 1.1; width / depth ratio of coxal plates III and IV (Fig. 5 A, C) 1 / 0.9 and 1 / 1, respectively; anterior and ventral margins of coxal plates III – IV with ten and seven setae each, respectively; with rounded anteroventral corners; coxal plates V and VI (Fig. 5 E, G) with large lobes anteriorly, provided with six and four setae, respectively; posterior margins with three and one setae each, respectively; coxal plate VII (Fig. 5 I) semicircular and with one strong and one simple setae on posterior lobe; coxal gills II – VI ovoid of which II and IV more elongated, length ratio of gills / bases of pereopods ~ 0.72 / 1, 0.84 / 1, 0.97 / 1, 0.83 / 1 and 0.73 / 1, respectively. Antenna I (Fig. 3 A): slender, ~ 48–50 % of body length; peduncular articles moderately slender, ratio 1 / 0.8 / 0.31; flagellum with 28 articles, most of them with two short aesthetascs each; accessory flagellum short, bi-articulated (Fig. 3 B), with several long apical setae; length ratio of antennas I / II in range of 1 / 0.60–0.75. Antenna II (Fig. 3 C): peduncular articles moderately stout, with several long setae along ventral margin, dorsal setae shorter than inner ones; flagellum relatively short with relatively short setae, consisting in males with 11 articles; peduncular articles II and III short, approx. as long as wide, peduncular articles IV and V slender, ~ 5 × and 6 × longer than wide, respectively, length ratio of 0.98–1 / 0.90 – 0.95; flagellum ~ 0.45–0.48 of length of peduncular articles IV + V. Labrum (upper lip) (Fig. 4 A) typical. Labium (lower lip) (Fig. 4 B): with entire, oblong oval outer lobes and well-developed smaller inner lobes. Mandible (Fig. 4 C, E): Left mandible (Fig. 4 C): incisor process with five teeth, lacinia mobilis with four teeth; with row of nine serrated setae between lacinia and molar process (Fig. 4 D); mandibular palp proximal article without setae, ~ 2 × longer than wide; mandibular article II / III (distal) ratio 1 / 0.3; article II with 12–13 simple setae; distal article with group of five A-setae; four groups of B-setae; 22 D-setae and six E-setae. Right mandible (Fig. 4 E): incisor process with four blunt teeth, lacinia mobilis bifurcate distally, with row of nine serrated setae between lacinia and molar process (Fig. 4 F). Maxilla I (Fig. 3 G): inner lobe with three simple distal setae, outer lobe with seven robust spines (2 spines with 2 strong lateral teeth and 3 spines with 1 strong lateral tooth (1–0 – 1 – 0 – 1 – 2 – 2) (Fig. 3 H)); palp bi-articulated, distal article with four simple setae distally. Maxilla II (Fig. 4 I): both plates with numerous long distal simple setae, outer lobe with row of fine setae along outer margin. Maxilliped (Fig. 4 J): inner plate short, with four distal robust setae intermixed with six distal simple setae; outer plate reaching half of palpal article II and bearing row of 20 or 21 distolateral spines and distal setae; palpal segment III with single median bundle of setae, along with single bundles of setae located at distal edge on both its internal and external surfaces; furthermore, large simple seta is situated at center of external margin of article; palpal article IV with one median seta at outer margin; nail shorter than pedestal, with small seta near basis. Gnathop