Eosymtes magnumoculis, Labay, 2022
publication ID |
https://doi.org/ 10.11646/zootaxa.5125.5.5 |
publication LSID |
lsid:zoobank.org:pub:CEFAEE61-3A55-4AC4-BDF5-B0937F3B0FDC |
DOI |
https://doi.org/10.5281/zenodo.6458205 |
persistent identifier |
https://treatment.plazi.org/id/DC0887DF-FFCA-FF5C-259A-FAF7FE85F96F |
treatment provided by |
Plazi |
scientific name |
Eosymtes magnumoculis |
status |
sp. nov. |
Eosymtes magnumoculis View in CoL sp. nov.
Figures 1b View FIGURE 1 , 2b, e, h, k, n View FIGURE 2 , 3c, d, e View FIGURE 3 , 4–9 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9
Diagnosis. Eyes large, reniform. Body smooth; urosome segment 2 not occluded dorsally.
Antenna 1, segments of peduncle without anterodistal process; flagellum with 27+ articles. Lower lip, outer lobes rounded not widely spread. Mandible, lacinia mobilis with 1–2 outer lateral processes. Maxilla 2, outer and inner plates densely setose. Maxilliped, inner plate reaching the 1/3 or 1/2 of palp segment 1; outer plate reaching about 0.5 x length of palp segment 2; palp segment 2 the longest, inner margin densely setose. Coxal plate 1–3 medium; coxal plate 4 much broader, deeply excavated posteroproximally; coxal plates 5–7 posterolobate, posteriorly rounded. Gnathopod 1, merus without acute tooth posterodistally, palmar margin without medial tooth, with 3 clusters of posterodistal strong setae (spines). Gnathopod 2, carpal lobe medium in length, merus with acute tooth posterodistally, palmar margin without medial tooth, with 2 clusters of posterodistal strong setae (spines). Pereopods 5–7, dactylus long, 0.5–0.51 times as long as propodus. Epimeral plate 3, posteroventral corner without a large process. Uropods 1–3, peduncle and ramie with numerous marginal small robust setae.
Male: unknown.
Type material. Holotype, female, 8.9 mm, Х 54400 View Materials /Cr-2428, Sea of Okhotsk , Far East of Russia (52º15493′ N 143º81916 E, 56 m), sands with silt, V. A. Alaskerov, 28 June 2019 . Paratype: 1 female, 6.5 mm, Х 54401 View Materials /Cr- 2429, with same data as holotype .
Additional material. Paratypes: 3 females, Х 54402 View Materials /Cr- 2430, Sea of Okhotsk , Far East of Russia (52º23,820 N 144º37,308 E, 160 m), sands with silt, M.G. Rogotnev, 26 July 2019 GoogleMaps ; 5 females, Х 54403 View Materials /Cr- 2431, Sea of Okhotsk, Far East of Russia (52º13,7879 N 143º81,9639 E, 45 m), sands, M.G. Rogotnev, 27 July 2019 ; 15 females, Х 54404 View Materials /Cr- 2432, Sea of Okhotsk , Far East of Russia (52º08,853 N 144º39,0695 E, 115 m), sands with silt, M.G. Rogotnev, 26 July 2019 GoogleMaps ; 1 female (from the author’s collection), 5.2 mm, Sea of Okhotsk , Far East of Russia (50º00 N 144º155 E, 96 m), silt, I.N. Moukhametov, 22 June 2020 ; 1 female (from the author’s collection), 4.8 mm, Sea of Okhotsk , Far East of Russia (50º00 N 144º155 E, 96 m), silt, I.N. Moukhametov, 22 June 2020 ; 9 females (from the author’s collection), Sea of Okhotsk , Far East of Russia (50º00 N 144º155 E, 96 m), silt, I.N. Moukhametov, 22 June 2020 ; 1 female (from the author’s collection), 6.3 mm, Sea of Okhotsk , Far East of Russia (55º93,87 N 155º32,31 E, 54 m), sands, N. V. Shalaputin, 28 July 2020 .
Type locality. The eastern coast of Sakhalin Island , Sea of Okhotsk, Far East of Russia (52º15,493 N 143º81,916 E, 56 m) .
Description. Female (8.9 mm). Rose-coloured when alive; color in alcohol almost white-colourless. Body smooth ( Fig. 4a View FIGURE 4 ). Microstructure of surface with wavy striation ( Fig. 8e View FIGURE 8 ).
Head ( Fig. 4b View FIGURE 4 ): slightly shorter than pereonites 1 & 2 combined; Rostrum short, about 1/8 times as long as peduncular segment 1 of antenna 1, apex acute; eyes large, subreniform, light-brown; anterior head lobe prominent, rounded, lower margin processed ahead by the acute tooth. Antenna 1 ( Fig. 4g, h View FIGURE 4 ): medium length; flagellum bearing 27+ articles; peduncle article 1 is 2 times as long as article 2, with a few short simple setae at the distal corner of lower margin, segments 1 & 2 without large anterodistal process each, article 3 3/5 times the length of article 2; accessory flagellum scale-like. Antenna 2 ( Fig. 4i View FIGURE 4 ): broken, peduncular articles 1, 2 together 1.7 times as article 3 length; article 1 with posterodistal protrusion, article 4 0.86 times as article 5, both with 3 tufts of simple setae at the lower margin each; flagellum segments with a crown of short setae around distal margin. Upper lip ( Fig. 4c View FIGURE 4 ): apical lobes slightly asymmetric, without terminal setae. Mandible ( Figs. 4d, e, f, j, k, l, m View FIGURE 4 , 5g View FIGURE 5 ): incisor margins with 6 teeth, accessory spine rows with 6–7 slender blades; lacinia mobilis with 1–2 outer lateral processes; molar strong, columnar, with strongly ridged grinding surface and with a medial molar seta; palp 3-articulate, article 1 of palp with or without distal seta, segment 2 with an indefinite-quantity (8–20) of simple setae (D-2 setae), segment 3 subequal to segment 2, with posterior row of 11–12 specific plumose D3-setae and with a few long simple setae, with group of 3 long plumose distal E3-setae and one short simple E-3 seta. Lower lip ( Fig. 5f View FIGURE 5 ): inner lobes small; outer lobes ovoid, setose. Maxilla 1 ( Fig. 5a View FIGURE 5 ): inner plate short, with 2 plumose setae apically; outer plate elongate, apically with 2 rows of 9 strong setae (setae of anterior row bifurcate, setae of posterior row pectinate); palp 2-articulate, article 2 with rare thin simple setae at the outer surface and with a subapical row of 6–7 simple setae, apical margin of article 2 with 7–8 long stout spine-like setae. Maxilla 2 ( Fig. 5b View FIGURE 5 ): inner plate with 2 strong plumose setae on the inner margin. Maxilliped ( Fig. 5c View FIGURE 5 ): inner plate middle length, reaching the 1/3 or 1/2 of palp segment 1, with 3–4 short annulate and conate setae, without setules (Watling type II.A4) ( Watling 1989) at the truncated apex; outer plate reaching about 0.5 x length of palp segment 2, rounded outer-apically and with rectangular inner corner, inner margin with submarginal row of simple setae, apex with 3 strong setae; palp 4-articulate, the percentage of total length of the articles of the palp 20.0% (article 1), 31.4% (article 2), 26.9% (article 3) and 21.7% (article 4); article 3 with specific setae, which plumose in the middle part; article 4 (dactylus) slender, slightly curved.
Pereon: Gnathopod 1 ( Fig. 5d, e View FIGURE 5 , 9a, b, f, g View FIGURE 9 ): coxa short, slightly pulled forward, with one small posterodistal cusp, inner side with oblique belt of short robust setae; basis slightly concave anteriorly and convex posteriorly, with anterior submarginal row of simple setae at the inner surface, more long in the distal part; merus with 2 tufts of simple setae and with a short row of long simple setae along the posterior margin; carpus 0.71 times as long as propodus, posterior lobe short, shallow, with 3 tufts of simple setae along posterior margin and with posterodistal row of numerous specific setae, which plumose in the middle part, crossing over at the distal margin; propodus 1.8 times as long as wide, palmar margin oblique, roundly passing to the posterior margin, 1.37 times as long as posterior margin, without medial tooth, with 3 clusters of posterodistal robust setae; dactylus shorter than palmar margin of propodus, slightly curved. Gnathopod 2 ( Fig. 6a, b View FIGURE 6 , 9c, d, e View FIGURE 9 ): coxa short, subquadrate, with one small posterodistal cusp; basis long, slightly concave anteriorly and convex posteriorly, with dense rows of short simple setae along anterior and posterior margins; merus with two groups of simple setae along posterior margin, distal margin truncated, with a few simple setae and with an acute tooth at the posterior angle; carpus medium, 0.68 times as long as propodus, posterior lobe shallow, with 3 tufts of setae along posterior margin and with a crown of long setae at the distal margin of lobe; propodus expanded distally with oblique palmar margin, 1.8 as long as wide, with 3 groups of simple setae at the posterior margin, palmar margin 0.89 times as long as posterior margin, without medial tooth, with 2 clusters of posterodistal strong setae (spines); dactylus slightly shorter than palmar margin, slightly curved. Pereopod 3 ( Fig. 6c View FIGURE 6 ): coxa rectangular, 1.8 times as long as wide, with one small posterodistal cusp; leg slender; basis sublinear, slightly concave anteriorly and convex posteriorly, with dense row of short simple setae along anterior margin and with few groups of setae at the posterior margin; merus 1.14 times as long as carpus, produced forwards along anterior margin of carpus; propodus long, 1.36 times as long as carpus; dactylus long, 0.51 times as long as propodus. Pereopod 4 ( Fig. 6d View FIGURE 6 ): coxa 1.28 times as long as wide, with deep excavation in the proximal ¼ of posterior margin; basis to dactylus as for pereopod 3. Pereopod 5 ( Fig. 7a View FIGURE 7 ): coxa antero- and posterolobate, with rounded ventral front margin, posterior lobe pulled back and down, rounded distally; basis with posterior lobe, width 0.75 times as length, slightly expanded distally, posterior margin slightly convex, crenulated; merus produced forwards along posterior margin of carpus; carpus more narrow and 0.6 times as long as merus; propodus linear, 1.7 times as long as carpus; dactylus long, 0.53 times as long as propodus, weakly curved, slender. Pereopod 6 ( Figs. 7b View FIGURE 7 ): coxa posterolobate, with truncated front margin, posterior lobe deep, pulled back and down, rounded distally; basis suboval, broadened, with distinct posterior lobe, posterodistal corner rounded, width 0.81 times length, posterior margin convex, crenulated; merus produced distally along posterior margin of carpus, narrow; carpus 0.67 times as long as merus; propodus sublinear, 1.49 times as long as carpus; dactylus long, 0.54 times as long as propodus, weakly curved, slender. Pereopod 7 ( Fig. 7c View FIGURE 7 ): coxa half-rounded; basis broadened, with distinct posterior lobe, posterodistal corner rounded, width 0.79 times length, posterior margin convex, crenulated; ischium; merus, carpus, propodus and dactylus as in pereopod 6. Coxal gills on pereopods 2–6. Coxal gill 6 smaller than gill 5.
Pleon: Epimeral plates: ( Fig. 7d, e, f View FIGURE 7 ) plates 1–3, posterior corners with small tooth each; plate 1 rounded triangular, without setae; plate 2, ventral margin convex, with 3–4 thin spine-like setae; plate 3, posterior margin rounded, ventral margin straight with 3 spine-like setae in anterior half. Pleopods: ( Fig. 7g, h, i, j, k View FIGURE 7 ) normal; inner ramus slightly shorter than outer ramus, coupling basis of inner ramus with 4–6 specific stout two-pointed plumose setae along inner margin (6 setae on pleopod 1, 5 setae on pleopod 2 and 4 setae on pleopod 3). Uropod 1: ( Fig. 8a View FIGURE 8 ) peduncle 1.2 times as long as outer ramus, with numerous marginal small spine-like setae and with large spinelike setae at the outer-distal corner; outer ramus 0.92 times as long as inner ramus. Uropod 2: ( Fig. 8b View FIGURE 8 ) inner ramus 1.26 times longer than peduncle; outer ramus 0.76 times as long as inner; peduncle and both rami with numerous marginal small spine-like setae. Uropod 3: ( Fig. 8c View FIGURE 8 ) inner ramus 2.1 times longer than peduncle, with acute and non-spinose apex; outer ramus about 0.71 times as long as inner; outer ramus with a row of 6 small spine-shaped setae along lateral and medial margins each, with acute and non-spinose apex. Telson: ( Fig. 8d View FIGURE 8 ), width 0.65 times length, linguiform, apically rounded, with 2 subapical notches, length about 1.6 x width, with proximal ventral keel, plumose marginal penicillate setae are absent.
Male: unknown.
Etymology. Species name magnumoculis is based on the Latin “magnum oculis” (large-eyed), reflecting the size of the eyes. The name is masculine.
Ecology: Eosymtes magnumoculis was found in the depth interval of 45–160 m on the sands and silt bottom in the layer of constant low temperature (-1.2 – +0.5°C). Females with developed marsupium were encountered in June and July. The species is found on the shelf of north-eastern Sakhalin Island and on the shelf of western Kamchatka Peninsula.
Distribution: The Sea of Okhotsk; on the shelf of north-eastern Sakhalin Island and western Kamchatka Peninsula ( Fig. 11 View FIGURE 11 ).
Remarks. Eosymtes magnumoculis sp. nov. is morphologically similar to the species E. minutus ( Bousfield and Hendrycks 1994; Hendrycks and Bousfield 2004). E. magnumoculis differs from E. minutus by the following combination of character states ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ): big eyes; maxilla 2, outer and inner plates densely setose; maxilliped, palp segment 2, inner margin densely setose; uropods 1–3, peduncle and rami with numerous marginal short spinelike setae.
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Royal British Columbia Museum - Herbarium |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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