Nihonotrypaea makarovi, Marin, Ivan, 2013

Marin, Ivan, 2013, A new species of callianassid ghost shrimp of the genus Nihonotrypaea Manning & Tamaki, 1998 (Crustacea, Decapoda, Axiidea, Callianassidae) from southern part of the Russian coast of the Sea of Japan, Zootaxa 3694 (5), pp. 434-444 : 435-442

Nihonotrypaea makarovi sp. nov.

( Figs. 1–5 )

Material examined. Holotype, male (cl. 8.0 mm, tl. 40 mm) (ZM)—Sea of Japan, Russia, southern Posiet Bay, Furugelma, Island, Zapadnaya Bay, 42°27’60”N 130°54’32”E, depth 10 meters, sand bottom, collected from burrows with yabby pump, coll. I. Marin, 22–23 June 2012. Paratypes: 3 males and 12 females (LEMMI)—the same locality as fort he holotype; 1 female (LEMMI) - Sea of Japan, Russia, southern Posiet Bay, Sivuchiya Bay, 42°27'54"N 130°47'40"E, depth 12 meters, muddy sand bottom, collected from burrows with yabby pump, coll. I. Marin, 21 June 2012; 3 ovigerous females and 3 males (LEMMI) – Sea of Japan, Russia, Peter the Great Bay, Vostok Bay, Priboynaya, 42°53'02"N 132°43'38"E, depth 10–12 meters, muddy sand bottom, collected from burrows with yabby pump, coll. K. Dudka, 10 Jule 2013.

Description. Carapace ( Figs. 1 , 2 , 3 a–c) about 0.3 of total body length; anterolateral projections obtuse; dorsal oval well marked, smooth; with well marked linea thalassinica; rostrum broadly triangular, sharp distally, reaching about 0.2 length of eyestalk. Telson ( Fig. 3 e) trapezoid, about 1.2 times as broad as long; dorsal surface with shallow median rounded sulcus; dorsolateral ridges low, unarmed; lateral margin smooth, unarmed; posterior margin generally convex, with small median sharp projection.

Eyestalk ( Fig. 3 b, c) flattened, subtriangular distally in dorsal view, reaching distal margin of basal antennular segment; lateral margin distinctly sinuous, anterolateral margin forming thin ridge extending to rounded terminal margin; cornea subterminal, well marked.

Antennula ( Fig. 3 b, c) with peduncle shorter than antennal, reaching the midlength of distal article of antennal peduncle, distal articles subcylindrical; distal article about 4 times as long as wide, about 2 – 2.5 times longer than previous, with row of long setae along inner lateral margin; antennular flagella both longer than peduncle, equal in length, with more than 20 articles.

Antenna with ( Fig. 3 a–c) with rudimentary scaphocerite, pedunclar articles subcylindrical; forth antennular article slender, about 2 – 2.5 times as long as wide; fifth antennular article about 4 times as long as wide, antennal flagella slightly longer than carapace length, with sparse fringe of elongate setae laterally.

Mouthparts without specific features; mandible with palp consisting of 3 articles, incisor and molar proceses normal, well developed, with several teeth of different size; maxillule with small palp, and subquadrate coxal endite; maxilla with endopod and large scaphognthite; first maxilliped with rudimentary endopod, well developoed exopod and bilobed epipod; second maxilliped without specific features, with curved exopod, without epipod and podobranch; third maxilliped ( Fig. 3 d) without exopod; ischium-merus operculiform; ischium about 1.5 times wider than long, and slightly shorter than merus, crista dentata consisting of row of small acute spines; merus about as wide as long, mesoodistal lobe expanded; distal segments (carpus, propodus, dactylus) slender, witout specific features.

First pereopods (chelipeds) greatly unequal and dissimilar, differ in males and females by armature of distal segments ( Figs. 1 , 2 , 5 a–c). Major cheliped in males ( Figs. 1 , 4 , 5 a) massive, with smooth segments, about twice as long as carapace length; coxa subqaudrate, about as long as wide; basis about 1.3 times as long as wide, with serrated ventral margin, about half as long as ischium; ischium moderately slender, widenning distally, about 3 times as long as proximal width, dorsal margin slightly sinuous in medial part, ventral margin sinuous armed with a row of teeth and tubercles; merus relatively strong and stout, about 1.4 times longer than ischium, and equal to carpus, slightly tapering distally, dorsal margin straight, with row of small, occasionally spinulose tubercles, ventral margin with large sharp curved hook-like proximal process separated by deep groove from serrated convexity in medial part and a cluster of several blunt teeth in distal part; carpus subquadrate, shovel-like, with bended margins, dorsal margin straight, smooth, ventral margin convex, with smooth proximoventral margin, distoventral margin serrated; palm subquadrate, shovel-like, with greatly bended ventral margin ( Fig. 4 ), subequal to carpus, smooth, dorsal margin, straight and smooth, parallel to ventral margin, ventral margin straight, covered with numerous blunt tubercles in mesial and distal parts; fingers about 2 – 2.5 times shorter than palm, fixed finger subtriangular, slightly smaller than dactylus, with sinuous dorsal and straight ventral margin, with sharp or bluntly produced tip curved upward; dactylus simple, curved downward, with sinuous ventrral margin forming proximal and medial blunt teeth, dorsal margin smooth and curved, with sharp or bluntly produced curved tip.

Major cheliped in females ( Fig. 2 , 5 b) generally similar to males, less massive and more slender; distal segments unarmed and smooth, carpus and palm subquadrate, with unarmed parallel margins.

Minor cheliped ( Figs. 1 , 2 , 5 c) generally similar between males and females, about 1.3 – 1.4 times as long as carapace, with relatively slender and smooth segments; coxa subqaudrate, about as long as wide; basis about 1.3 times as long as wide, with serrated ventral margin, about half as long as ischium; ischium slender, about 3.5 times as long as wide, slightly widenning distally, about 2 times as long as merus, with straight unarmed margins; merus short, suboval, about twice longer than minimal width, with convex serrated outer margin bearing small sharp tooth in its midlength; carpus relatively slender, about 3 times as long as wide, about twice longer than merus and 1.5 times longer than palm, shovel-like with proximoventral margin broadly excavated ( Fig. 3 b); palm slender, slightly longer tha length of fingers, with straight unarmed margins; fingers slender, about 4 times as long as wide, subequal, simple, with straight cutting edges and sharp curved tips.

Second pereopod ( Fig. 5 d) chelate, slender; coxa subcylindrical, about as long as wide, equal to ischium; basis short, as long as wide; ischium smooth, short, as long as wide, equal to basis and about 3 times shorter than merus; merus widenning proximally and tapering distaly, with sinuous ventral margin, about 3 times as long as minimal width, about 1.5 times longer than carpus; carpus triangular, smooth, about as long as wide, subequal to chela; chela triangular, with fingers tapering distally, with palm subequal to fingers; dactylus and polex triangular, terminating in small sharp tips, wih simple simple cutting edges, furnished with tufts of simple setae along margins.

Third pereopod ( Fig. 5 e) simple, moderately slender; coxa subcylindrical, about as long as wide, equal to ischium; basis short, as long as wide; ischium subquadrate, about as long as wide, about 3 times shorter than merus; merus smooth, about 2.5 – 3 times as long as wide, with slightly convex margins; carpus smooth, button-like, about as long as maximal width; propodus subrectangular, fan-like, twice longer than wide, with broad bluntly rounded proximoventral margin, with numerous tufts of setae along margins; dactylus subovoid, blunt distally, about 1.5 times as long as wide, lateral surface covered with short setae, dorsal and ventral margins with numerous short stiff-like setae.

Forth pereopod ( Fig. 5 f) simple, slender, with smooth segments; coxa subcylindrical, about as long as wide; basis about 1.3 times as long as long, suequal to coxa; ischium slender, about 2.3 times as long as wide, slightly shorter than merus; merus smooth, about 4 times as long as wide, with straight ventral and convex dorsal margin; carpus subcylindrical, about twice longer than wide, subequal to propodus; propodus subcylindrical, about 4 times as long as wide, with straight margins, with spiniform setae obscured by brush of dense setae distoventrally; dactylus subovoid, blunt distally, about 1.5 times as long as wide, terminating in small, ventrolaterally directed corneous tip, densely setose.

Fifth pereopod ( Fig. 5 g) subchelate, with same proportions as forth pereopod; distolateral corner of propodus and dactylus forming small subchela with slender “fingers“, distoventral margin of propodus and dactylus densely covered with tufts of stiff-like strong setae and short simple setae.

Pleopods without specific features; first pleopod composed of two articles in both male and females, in females first pleopod with spatulate distal article bearing setae. Second pleopod absent in males and well developed in females with exopod about twice longer than endopod, endopod bearing long setae. Third ( Fig. 3 f–i), forth and fifth pleopods biramous, without specific features; appendix internae ( Fig. 3 g, i) projecting beyond margin of endopod in both males and females, with distodorsal margin bluntly projecteing forward.

Uropod ( Fig. 3 e) with smooth endopod and exopod; endopod quadrate, about as long as wide, with unarmed margins, with long simple setae along its border; exopod trinagular in shape, slightly wider than long, with with distodoral margin convex, well visually separated from posterior margin; dorsal plate with distal row of setae distinctly separated from setal row of posterior margin.

Coloration. Body and appendages generally yellow-greenish, females more colourless; cornea dark brown; gonads brown; gonads brown in males and orange in females ( Figs. 1 , 2 ). Small-sized specimens are whitish.

Measurements. The total body length (tl.) of the largest male— 40 mm, carapace length (cl.)—9.0 mm; the total body length (tl.) of the largest female— 38 mm, carapace length (cl.)—8.0 mm.

Variation. Major cheliped in males ( Fig. 4 ) shows some morpological variations in the armature of fingers similar to other callianassid species (e.g., Sakai 1969): 1) fingers with marked deep groove in proximal part of polex ( Fig. 4 b, c, g), with a marked gap between fingers, fingers more robust, with bluntly rounded tips, and 2) more slender fingers with sharp curved tips, without marked groove between finger and at proximal part of pollex ( Fig. 4 a, c, g), fingers almost bordering one to another. Such morphological species-specific differentiation of major cheliped is also characterictic for males of Nihonotrypaea japonica in the Sea of Japan resulted in a description of several forms and even species (see Makarov, 1938; Sakai, 1969; Vinogradov, 1950; Marin, pers. observ.)

Etymology. The species is named after the Russian scientist V.V. Makarov, who made the first review of callianassid shrimps from Russian seas.

Habitats. The species was found living in burrows made in well washed sand (Furugelma Island) or muddy sand (Vostok Bay, Sivuchiya Bay) in depths from 8 to 12 – 14 meters; water with normal marine salinity. The shrimps probably live separately one from another as two specimens of shrimps were never pumped together. The burrow openings were small mounds (about 10 cm in diametr and 10 cm height) with several adjacent funnels.

Distribution. The species is presently known only from the north-west coast of the Sea of Japan, within the Peter the Great Bay—at Vostok Bay (Priboynaya Bay, 42°53'02"N 132°43'38"E) and Posiet Bay (Furugelma Island, 42°27’60”N 130°54’32”E (the type locality) and Sivuchiya Bay, 42°27'54"N 130°47'40"E).

Figures

FIGURE 1. Nihonotrypaea makarovi sp. nov., males, a, b — CL 8.0 mm, TL 38 mm, c – e — CL 9.0 mm, TL 40 mm: a, c — dorsal view, b, d — lateral view, e—carapace and appendages, dorsal view.

FIGURE 2. Nihonotrypaea makarovi sp. nov., mature females, a, b — CL 6.5 mm, TL 30 mm, c - e — CL 8.0 mm, TL 38 mm: a, c — dorsal view, b, d — lateral view, e—carapace and appendages, dorsal view.

FIGURE 3. Nihonotrypaea makarovi sp. nov., a, b, d – g — mature male, c, h, i — mature female: a — front of carapace, lateral view; b, c — front of carapace, dorsal view; d — third maxilliped; e — telson and uropods; e, g — third pleopod; f, h — same, appendix interna.

FIGURE 4. Nihonotrypaea makarovi sp. nov., major cheliped of males, a, b — cl. 8.0 mm, tl. 38 mm; c — cl. 6 mm, tl. 32 mm; d, e, f — cl. 7.0 mm, tl. 35 mm; g — cl. 9.0 mm, tl. 40 mm: a, d — dorsal and mesiodorsal view, respectively; b, c, e g — lateral outer surface, f — lateral inner surface.

FIGURE 5. Nihonotrypaea makarovi sp. nov., a — mature male, b – g — non-ovigerous female: a, b — major cheliped; c — minor cheliped; d — second pereopod; e — third pereopod; f — forth pereopod; g — fifth pereopod.