Paramoera (G.) tiunovi, Sidorov, Dmitry A., 2010

Sidorov, Dmitry A., 2010, A new subgenus of eusirid amphipod (Crustacea: Amphipoda: Eusiridae) from subterranean waters and springs of the Eastern Sikhote-Alin Mountain Ridge, with comments on the morphology of sternal humps, genital papillae and pleopods, Zootaxa 2518, pp. 1-31 : 15-24

publication ID	https://doi.org/ 10.5281/zenodo.196181
DOI	https://doi.org/10.5281/zenodo.6203286
persistent identifier	https://treatment.plazi.org/id/03D0B76B-FF80-D265-B1FF-FC12FD22FAF4
treatment provided by	Plazi
scientific name	Paramoera (G.) tiunovi
status	sp. nov.

Treatment

Paramoera (G.) tiunovi sp. nov.

Figures 39–75 View FIGURES 34 – 39 View FIGURE 40 View FIGURES 41 – 42 View FIGURES 43 – 51 View FIGURES 52 – 56 View FIGURES 57 – 64 View FIGURES 65 – 69 View FIGURES 70 – 71 View FIGURES 72 – 75

Diagnosis. Dorsal surface of body segments smooth, bearing detached fine setae ( Figs 39 View FIGURES 34 – 39 , 40 View FIGURE 40 ). Eyes presented ( Figs 40 View FIGURE 40 , 65 View FIGURES 65 – 69 ), ommatidia reduced, weakly pigmented. Vital body color is light yellowish. Head with rostral point ( Fig. 66 View FIGURES 65 – 69 ). Inferior antennal sinus moderate, sub-rounded ( Fig. 65 View FIGURES 65 – 69 ). Antenna 1 10% longer than antenna 2. Ventral margins of epimera 1–3 unarmed. Ventral surface of urosomite 1 bearing 2 notched robust and 4 flexible setae. Uropod 3 with a naked peduncular process. Telson as long as uropod 3 peduncle. Ventral surface of pereonites 2–7 with sternal humps. Body length 5.7 – 8.0 mm (females), 4.0 – 6.0 mm (males).

Material examined. Holotype: female, 8.0 mm, 1/88501-ZINRAS, Russia, Primory Territory, Olginsky District, the Avvakumovka River basin, a spring on the bank of the Solontsovaya River (right tributary of the Mineralnaya River), ~ 1 km S of Gornovodnoye, near road bridge (43°41.858'N 134°44.086'E), 15 May 2005, coll. D.A Sidorov & M.P. Tiunov. Paratypes: 15/2sd-IBSS, 2 females (7.2 mm, 7.0 mm), 2 males (6.0 mm, 5.2 mm), with same data as holotype.

Additional material examined (not placed in the type series): 2 females (7.5 mm, 5.7 mm), 4 males (2x 5.0 mm, 4.7 mm, 4.0 mm), with same data as type series. Deposited at the IBSS.

Description. Female (8.0 mm). Head. Antenna 1 ( Fig. 57 View FIGURES 57 – 64 ): 50% length of body, about 10% longer than antenna 2; peduncular articles 1–3 have a length ratio of 1:0.74:0.48; primary flagellum with 30 articles; next nearest flagellar articles bearing lanceolate aesthetascs accompanied by setae; calceoli absent; accessory flagellum 1-articulate, scale-like bearing 4 setae, one of which plumose. Antenna 2 ( Fig. 58 View FIGURES 57 – 64 ): gland cone acute with 2 short apical setae; peduncular article 4 slightly longer than article 5, both articles setose with short setae; flagellum with 21 articles; calceoli absent; some distal flagellar articles bearing a rod-shaped structure accompanied by setae. Upper lip ( Fig. 46 View FIGURES 43 – 51 ): trapeziform with minute setae at apex. Lower lip ( Fig. 47 View FIGURES 43 – 51 ): inner lobes vestigial. Mandibles subequal: left mandible ( Fig. 49 View FIGURES 43 – 51 ) with incisor 6-dentate, lacinia mobilis 5-dentate, setal row with 6 serrated setae, triturative molar with small plumose seta; palp article 2 as long as article 3 with 7 setae, article 3 bearing 2 A-setae, 5 B-setae, 4 C-setae, 9 D-setae and 4 E-setae; incisor of right mandible ( Fig. 50 View FIGURES 43 – 51 ) 6-dentate, lacinia mobilis trifurcate, setal row with 6 serrated setae. Maxilla 1, left ( Fig. 43 View FIGURES 43 – 51 ): inner plate with 8 plumose setae, outer plate ( Fig. 48 View FIGURES 43 – 51 ) with 10 pectinate robust setae; palp articles 1–2 have a length ratio of 0.4:1, article 2 bears 6 robust setae apically and 1 stiff seta sub-apically; right palp massive ( Fig. 44 View FIGURES 43 – 51 ), articles 1–2 have a length ratio of 0.37:1, article 2 bears 6 short strong and 1 long slender setae on apex with 1 stiff seta sub-apically. Maxilla 2 ( Fig. 45 View FIGURES 43 – 51 ): inner plate with oblique row of 5 plumose setae on inner margin; outer plate broader, with 12 slender setae on apex. Lateralia: sub-rectangular, bearing 16 unguliform slightly pectinate setae accompanied by stiff setae. Maxilliped ( Fig. 51 View FIGURES 43 – 51 ): peduncle sub-quadrate with 3 long setae on inner face; inner plate apically with 2 simple strong peg setae, 4 short setae on inner face, 14 plumose setae extending from inner margin to apex; outer plate with a row of 7 medial robust setae, 24 naked setae and 5 apical plumose setae; palp articles 1–2 have a length ratio of 0.75:1, article 2 oblong with a row of simple setae on inner margin and 3 simple setae on outer margin; dactylus with 4 setae along inner margin and 1 marginal seta on outer face. Pereon. Gnathopod 1 ( Fig. 41 View FIGURES 41 – 42 ): coxa deep with 7 short setae on ventral margin and 1 long setae on disto-posterior face; basis stout with 5 long and 1 short setae on anterior margin and with 12 long and 1 short setae on posterior margin; carpus as long as propodus; propodus of gnathopod 1 smaller than propodus of gnathopod 2; propodus sub-rectangular, palm slightly convex with cutting margin developed and armed with 6 distally notched robust setae near defining angle; posterior margin much longer than palm with 4 sets of setae; dactylus weakly dentate along inner margin with 1 seta on outer face, nail short with 2 minute setae at hinge. Gnathopod 2 ( Fig. 42 View FIGURES 41 – 42 ) larger than gnathopod 1; coxa deep with 5 short setae on ventral margin and 3 long setae on disto-posterior face; basis sub-linear with 4 long and 4 short setae on anterior margin and with 2 sets of long and 1 short setae on posterior margin; carpus 1.4x longer than propodus; propodus sub-rectangular, palm convex with cutting margin developed and armed with 6 distally notched robust setae near defining angle; posterior margin 2x longer than palm with 5 sets of setae; dactylus similar to that of gnathopod 1. Pereopod 3 ( Fig. 52 View FIGURES 52 – 56 ): shorter than pereopods 5–7; coxa deep with 5 short setae on ventral margin and 3 long setae on disto-posterior face; basis sub-linear with 1 set of long setae on posterior margin; dactylus about 30% length of corresponding propodus bearing 2 minute setae in base of nail. Pereopod 4 ( Fig. 53 View FIGURES 52 – 56 ): sub-similar to pereopod 3; coxa sub-quadrate with a row of 17 short setae along ventral margin. Pereopods 5–7 ( Figs 54–56 View FIGURES 52 – 56 ): sub-similar, but 5 and 6 shorter than 7; coxal plates 5 and 6 bilobate, posterior lobes larger than anterior ones and armed with 2 short setae on posterior margin; bases broad with densely serrated posterior margins and 1 set of shortened setae on anterior margin; dactyli about 37% length of corresponding propodi bearing 2 minute setae in base of nail. Coxal gills 2–7 ( Figs 42 View FIGURES 41 – 42 , 54 View FIGURES 52 – 56 ) stalked and saccular. Ventral surface of pereonites 2–7 ( Fig. 39 View FIGURES 34 – 39 ) bearing sternal humps. Oostegites 2–5 ( Fig. 42 View FIGURES 41 – 42 ) on gnathopod 2 and pereopods 3–5. Pleon. Epimera 1–3 ( Fig. 59 View FIGURES 57 – 64 ): posterior margins weakly convex (but straight in plate 2) with 1 small seta on plates 2 and 3; anterior margins of plates 2 and 3 with 1 set of shortened setae each; posterior corners acute in plates 1 and 3 with small recession with indistinct notches and setae for each plate; ventral margins of plates without setae. Pleopods 1–3 ( Fig. 68 View FIGURES 65 – 69 ): subequal peduncular articles with 2 retinacula each and a sparse sets of fine setae on inner and outer margins; 3 bifurcate setae on outer margin of first article of inner ramus; small process enclosed with 5 plumose setae ( Fig. 69 View FIGURES 65 – 69 ) on the inner face of the first articles of outer rami; rami sub-equal in length and fringed with plumose setae. Urosome ( Fig. 67 View FIGURES 65 – 69 ): urosomites with sparse fine setae on dorsal margin; urosomite 1 saddle-shaped dorsal with 2 notched robust and 4 flexible setae on ventral margin. Uropod 1 ( Fig. 60 View FIGURES 57 – 64 ): peduncle with 7 setae on outer margin and 4 setae on inner margin; outer ramus 0.9x as long as inner ramus, approximately 60% length of peduncle; both rami armed with setae on outer margins with 4 setae on apices but inner margins unarmed. Uropod 2 ( Fig. 61 View FIGURES 57 – 64 ): peduncle with 4 setae on outer margin and 1 distal (corner) seta on inner margin; outer ramus 0.74x as long as inner ramus, approximately 66% length of peduncle; both rami armed with setae on outer margins with 4 setae on apices but inner margins unarmed. Uropod 3 ( Fig. 62 View FIGURES 57 – 64 ): biramous; peduncle with an unarmed peduncular process, 2 fine setae on proximodorsal face and 2 setae on distal margin; outer ramus 0.9x as long as inner ramus, somewhat longer than peduncle; rami lanceolate, armed with notched setae and simple setae on outer and inner margins with 1 simple seta sub-apically. Telson ( Figs 63, 64 View FIGURES 57 – 64 ): as long as uropod 3 peduncle; 0.3x longer than broad, cleft about 60% of its length; tips of lobes notched with 1 or 2 small setae apically.

Male (6.0 mm). Similar to female but with a smaller body size and differing in the following characteristics. Head. Antenna 1 and 2 with calceoli of pontogeneiid type ( Lincoln & Hurley 1981). Antenna 2 ( Fig. 72 View FIGURES 72 – 75 ): gland cone with 1 short apical setae; flagellum with 22 articles, first 13 articles with calceoli accompanied with setae; distal flagellar articles with rod-shaped structure similar to female. Pereon. Gnathopod 1 ( Fig. 70 View FIGURES 70 – 71 ): propodus of gnathopod 1 slightly smaller than that of gnathopod 2; coxa relatively short; carpus 0.83x as long as propodus; propodus sub-rectangular, palm straight armed with 6 distally notched robust setae near defining angle; posterior margin longer than palm with 4 sets of setae; dactylus weakly dentate along inner margin. Gnathopod 2 ( Fig. 71 View FIGURES 70 – 71 ) larger than gnathopod 1; coxa relatively short; carpus slightly longer than propodus; propodus sub-rectangular, palm straight and armed with 4 distally notched robust setae near defining angle; posterior margin much longer than palm with 5 sets of setae; dactylus similar to that gnathopod 1. Coxal gills 2–7 ( Fig. 71 View FIGURES 70 – 71 ) stalked and saccular. Genital papillae ( Fig. 75 View FIGURES 72 – 75 ) on ventral surface of pereonite 7; small sensory seta near base of genital papillae. Pleon. Pleopods 1–3 ( Fig. 73 View FIGURES 72 – 75 ): pleopods 1 and 3 ordinary, similar to that female; pleopod 2 modified, outer ramus stout, some shorter than inner ramus with 13 oblique articles, 2 last articles with a pair of strong and relatively short plumose setae, terminal article minute with a couple of small plumose setae. Telson ( Fig. 74 View FIGURES 72 – 75 ) similar to that of the female but 0.7x longer than broad, cleft about 50% of its length.

Taxonomic comments. P. (G.) tiunovi sp. nov. is distinguished (see Table 1) from P. (G.) myslenkovi sp. nov. (described above) by the following characteristics (characteristics of the latter in parentheses): eyes present (absent), antenna 1 50% length of body (70%), antenna 2 about 0.1x shorter than antenna 1 (0.4x), ventromedial face of peduncular articles of both antennae with short setae (with long setae), seta on outer face of palpal article 2 of maxilla 1 absent (present), maxilla 2 with 5 plumose setae in oblique row (6 setae), upper lip trapeziform (ovoid), vestigial inner lobes of lower lip present (absent), strong setae on ventral margin of maxilliped peduncle absent (present), article 2 of palp maxilliped oblong (stout), female gnathopods 1, 2 with 6 notched setae at defining angle (4 setae), ventral margin of epimeron 3 unarmed (armed), ventral margin of urosomite 1 with 4 flexible setae (2 short setae), peduncular process of uropod 3 naked (armed), plumose setae on rami of uropod 3 absent (present), telson as long as uropod 3 peduncle (much longer).

The new species are more closely related to each other than to other known forms (see Table 1), but it is possible to recognize several similarities between P. (G.) tiunovi sp. nov. and P. erimoensis collected from several stream mouths on Hokkaido: (1) eyes reduced, (2) antenna 1 somewhat longer than antenna 2, (3) outer face of maxilla 1, palpal article 2 without setae, (4) lower lip with vestigial inner lobes, (5) inner plate of maxilliped with 2 peg setae, (6) carpus length equal to propodus in female gnathopod 1, (7) defining angle in female gnathopod 2 with 6 notched setae, (8) posterior margins of epimera 1–3 without crenulation, (9) ventral margins of epimera 1–3 unarmed, (10) uropods 1–2 weakly setose, (11) rami of uropod 3 not plumose, (12) telson length equal to peduncle of uropod 3. P. erimoensis also has reduced eyes and lives in conditions that maybe classified as interstitial. It is likely that the morphological similarities between the species could be the reason for the similar ecological niches that they occupy.

Type locality. Russia, Far East, southeast part of Sikhote-Alin Mountain Ridge (4341.858'N 13444.086'E), the Solontsovaya River basin, nameless spring (seeps) (see Fig. 1 View FIGURE 1 ).

Ecology. The amphipods P. (G.) tiunovi sp. nov. were collected from small spring (seeps) on the bank of the Solontsovaya River at a depth of 5–10 cm in substrate consisting of a fine-grained sand and pebbles beneath leaves. The cup of the spring interflowed with the river and the bottom of it was covered with numerous gryphons. The amphipods Gammarus sp. and blind asellid isopods were collected from this same locality.

Marsupial plates of the collected specimens were not fully mature and were lacking setae.

Etymology. Species named in honor of our colleague chiropterologist Mikhail Petrovich Tiunov (Institute of Biology and Soil Science, Vladivostok).