Pandalopsis princeps, Komai & Hibino, 2019

Komai, Tomoyuki & Hibino, Mai, 2019, Three new species of the pandalid shrimp genus Pandalopsis Spence Bate, 1888 (Crustacea: Decapoda: Caridea) from the southwestern Sea of Okhotsk, with supplemental note on P. glabra Kobjakova, 1936, Zootaxa 4545 (1), pp. 1-31 : 17-24

publication ID	https://doi.org/ 10.11646/zootaxa.4545.1.1
publication LSID	lsid:zoobank.org:pub:53F8268A-2A6F-4454-A98D-EFE69FF7062D
DOI	https://doi.org/10.5281/zenodo.5941754
persistent identifier	https://treatment.plazi.org/id/3E681291-EA8E-4CAF-80DF-6D6EDE24D90E
taxon LSID	lsid:zoobank.org:act:3E681291-EA8E-4CAF-80DF-6D6EDE24D90E
treatment provided by	Plazi
scientific name	Pandalopsis princeps
status	sp. nov.

Treatment

Pandalopsis princeps n. sp.

[New Japanese name: Shirayuki-morotoge-ebi]

Figs. 10–14 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14

Material examined. Holotype. CBM-ZC 14624, ovigerous female (cl 31.3 mm), Nemuro Strait , Hokkaido, 44°12.16’N, 145°23.34’E, depth not recorded, 8 September 2015, shrimp trap, coll. K. Matsuzaki. GoogleMaps

Paratypes. CBM-ZC 14625, 2 ovigerous females (cl 33.3, 38.8 mm), same data as holotype; CBM-ZC 14626, 1 male (cl 25.0 mm), 1 transitional male (cl 32.2 mm), off Rausu, 44°12.17’N, 145°23.38’E, 600 m, 8 September 2014, shrimp trap, coll. K. Matsuzaki; CBM-ZC 14627, 1 male (cl 24.4 mm), 1 ovigerous female (cl 32.3 mm), off Rausu, other data unknown; AMF-ZC0027, 1 female (cl 35.8 mm), off Rausu, date not recorded, shrimp trap, coll. K. Matsuzaki, reared in aquarium until 13 December 2014; AMF-ZC0028, 1 male (cl 28.7 mm), 1 transitional male (cl 30.6 mm), 3 females (cl 31.5–33.6 mm), same data as CBM-ZC 14626 GoogleMaps ;

Description. Body ( Fig. 10A, B View FIGURE 10 ) moderately robust; no tegmental scales.

Rostrum ( Fig. 11A, B View FIGURE 11 ) distinctly overreaching distal margin of antennal scale, 1.1–1.8 times as long as carapace, noticeably curving dorsally; dorsal margin armed with 9–13 movable spines, including 4–7 on rostrum proper and 5–7 postorbital, and 1 or 2 small fixed spines near apex, subdistal 0.5–0.7 leaving unarmed, posteriormost postrostral spine located at midlength of carapace; ventral margin armed with 12–16 tooth-like spines gradually increasing in size proximally, but posteriormost spine slightly smaller than preceding one; lateral carina sharply delimited almost over entire length.

Carapace ( Fig. 11A, B View FIGURE 11 ) with postrostral carina moderately high, crested, extending to posterior 0.2 of carapace length; dorsal margin gently convex in lateral view with peak at posteriormost postrostral spine; faint suborbital lobe present; antennal spine moderately large; branchiostegal spine distinctly smaller than antennal spine; pterygostomial margin broadly rounded; no conspicuous ridges or carinae on lateral surface; carapace surface with scattered very short setae (these setae easily broken off, but setal punctae discernible); no patch of short setae near posterodorsal margin.

Pleon ( Fig. 10A View FIGURE 10 ; 11C View FIGURE 11 ) dorsally smooth, glabrous. Pleura 1–3 rounded, pleura 4 with small, ventrally curved posteroventral spine, pleuron 5 terminating posteriorly in large, ventrally curved spine. Pleomere 6 0.5–0.6 times as long carapace, 1.9–2.3 times as long as high, with small posteroventral spine; posterolateral process terminating in slender spine. Telson ( Fig. 11D View FIGURE 11 ) 1.4–1.5 times as long as pleomere 6, armed with 6–9 dorsolateral spiniform setae on either side; dorsal surface nearly flat, with median tuft of stiff setae proximally and scattered short stiff setae; posterior margin terminating in small blunt triangular projection bearing 4–6 small, unequal spiniform setae, flanked by 1 pair of longer, mesially curved spiniform setae.

Eye ( Fig. 11A, E View FIGURE 11 ) broadly subpyriform, maximal diameter of cornea 0.2 of carapace length; ocellar sinus present, but ocellus absent.

Antennular peduncle ( Fig. 11A. E View FIGURE 11 ) reaching midlength of antennal scale. Article 1 subequal in length to articles 2 and 3 combined, with cluster of stiff or long spiniform setae on dorsodistal margin; stylocerite short, rounded, not reaching midlength of peduncular article. Articles 2 with few minute spiniform setae on dorsodistal margin. Outer flagellum 1.8 length or more of carapace, with aesthetasc-bearing portion subequal in length to carapace.

Antenna ( Fig. 11A, E View FIGURE 11 ) with stout basicerite bearing moderately strong ventrolateral spine. Carpocerite not reaching midlength of antennal scale, reaching as far as article 1 of antennular peduncle. Antennal scale 0.8–1.0 times as long as carapace and 4.1–5.1 times as long as broad, lateral margin feebly concave; distolateral spine ( Fig. 11F View FIGURE 11 ) very slender, distinctly overreaching distal margin of rounded lamella.

Maxilliped 3 ( Fig. 12A View FIGURE 12 ) reaching or slightly overreaching distal margin of antennal scale. Ultimate article slightly longer than penultimate article (= carpus), terminating in small spiniform seta flanked by shorter spiniform setae ( Fig. 13A View FIGURE 13 ). Distal two articles setose with several tufts of short stiff setae on extensor surface and obliquely transverse rows of long bristle-like setae on lateral or flexor lateral surfaces. Antepenultimate article (merusischium-basis fused article) longer than distal two articles combined, dorsomesially with prominent, rounded crest at midlength, dorsal surface proximal to crest forming shallow concavity, bearing small, low tubercle near base; ventral margin keeled, with closely spaced short to long stiff setae. Exopod absent.

Pereopod 1 ( Fig. 12B View FIGURE 12 ) slightly shorter than maxilliped 3, minutely chelate, overreaching midlength of antennal scale. Propodus compressed laterally, gradually tapering, 0.7–0.9 times as long as carpus, with row of tufts of long stiff setae on extensor and flexor margins; mesial surface with field of dense stiff setae, composing grooming apparatus, on proximal 0.6. Propodus with extensor margin compressed to form low crest, both extensor and flexor margins with row of tufts of short to long, stiff setae. Carpus with row of tufts of short to long bristle-like setae on extensor and flexor margins. Merus with row of low protuberances on dorsal and ventral margins and tufts of short to long bristle-like setae directed mesially. Ischium ventrally with broad laminar expansion, fringed with closely set short to long stiff setae; terminal margin of lamina subacutely pointed or minutely denticulate.

Pereopods 2 ( Fig. 12C View FIGURE 12 ) subequal, overreaching antennal scale by length of chela. Chela 0.4–0.5 times as long as carpus; dactylus 0.6–0.8 times as long as palm. Carpus subdivided into 15–20 articles. Merus 0.5 times as long as ischium, without annulation. Ischium faintly sinuous, with ventral margin slightly expanded in proximal half to accommodate chela when carried flexed, margin of expansion fringed with short, curved, stiff setae.

Pereopods 3–5 generally similar, decreasing slightly in length toward posterior. Pereopod 3 ( Fig. 12D View FIGURE 12 ) overreaching antennal scale by 0.6 length of propodus. Dactylus ( Fig. 13B, C View FIGURE 13 ) about 0.2 times as long as propodus, gently curved, terminating in acute unguis clearly demarcated basally; flexor margin with 6–8 relatively long accessory spiniform setae almost over entire length, becoming longer and more widely spaced distally, and 1 subterminal slender spiniform setae contiguous to unguis. Propodus ( Fig. 13C View FIGURE 13 ) slightly widened distally; extensor surface with short stiff setae and tiny spiniform setae; lateral surface with single or double row of spiniform setae and short stiff setae adjacent to extensor margin; mesial surface with shallow median sulcus flanked by single or double row of slender spiniform setae ( Fig. 13D View FIGURE 13 ); flexor surface with slender spiniform setae increasing in size distally and arranged in irregular 2 or 3 rows, distal margin with 3 or 4 long spiniform setae. Carpus 0.6 times as long as propodus; extensor surface with single or double row of spiniform setae and short stiff setae over entire length; lateral surface with longitudinal row of short stiff setae along midline and 3–6 robust spiniform setae adjacent to flexor margin; mesial surface with scattered small, slender spiniform setae (spiniform setae adjacent to dorsal margin forming a row) ( Fig. 13E View FIGURE 13 ). Merus 0.9–1.1 times as long as carapace, armed with 8–12 lateral and 8– 12 ventral robust spiniform setae. Ischium with 1 ventrolateral robust spiniform seta.

Pereopod 4 ( Fig. 12E View FIGURE 12 ) overreaching antennal scale by 0.4–0.5 length of propodus. Dactylus ( Fig. 13F, G View FIGURE 13 ) about 0.2 times as long as propodus, armed with 6–8 accessory spiniform setae + 1 subapical spiniform seta. Carpus 0.5– 0.6 times as long as propodus, with 3–5 robust spiniform setae on lateral surface. Merus 0.8–1.0 times as long as carapace, with 7–11 lateral and 7–11 ventral robust spiniform setae. Ischium with 1 robust spiniform seta.

Pereopod 5 ( Fig. 12F View FIGURE 12 ) overreaching antennal scale by 0.3 length of propodus. Dactylus ( Fig. 12H, I View FIGURE 12 ) slightly shorter than those of pereopods 3 and 4, less than 0.2 times as long as propodus; flexor margin with 6–9 accessory spiniform setae + 1 subapical spiniform seta contiguous to unguis. Propodus ( Fig. 12I View FIGURE 12 ) slightly widened distally, subdistally with several prominent tufts of stiff setae, forming grooming apparatus; surfaces less setose than in pereopods 3 and 4; flexor margin with single row of slender spiniform setae, distal margin with cluster of 3 or 4 longer spiniform setae reaching proximal 0.3 of dactylus. Carpus 0.5–0.6 times as long as propodus, with 2–4 robust spiniform setae on lateral surface; extensor margin with few stiff setae; mesial surface with 2 longitudinal rows of tiny spiniform or bristle-like setae. Merus 0.9–1.1 times as long as carapace, with 5–9 lateral and 1–7 ventral robust spiniform setae. Ischium with 1 robust spiniform seta.

Endopod of pleopod 1 and appendix masculina on pleopod 2 showing sequential change with growth, suggesting protandrous hermaphroditism. Endopod of pleopod 1 in functional males ( Fig. 11G View FIGURE 11 ) relatively slender, with relatively stout appendix interna located terminally, and with slight shoulder lateral to base of appendix interna; in transitional males ( Fig. 11H View FIGURE 11 ), outer terminal lobule becoming distinct; in females ( Fig. 11I View FIGURE 11 ), endopod becoming broader, tapering to simple, bluntly pointed terminus. Appendix masculina of functional males ( Fig. 11J View FIGURE 11 ) slightly shorter than appendix interna, bearing several long spiniform setae on terminus to distal half of upper side; in transitional males ( Fig. 11K View FIGURE 11 ), appendix masculina reduced to half or less than half length of appendix interna, bearing very short setae terminally; in females, appendix masculina completely reduced.

Uropod ( Fig. 10A View FIGURE 10 ) with rami subequal in length, reaching to tip of telson.

Eggs large, 3.1–3.6× 2.9–3.2 mm (eyed stage).

Size. Largest functional male cl 28.7 mm, transitional males cl 30.6–32.2 mm, females cl 31.3–38.8 mm, ovigerous females cl 31.3–38.8 mm.

Colour in life ( Fig. 1B View FIGURE 1 ). Carapace whitish translucent, rostrum red. Pleon mottled with red, posterior edges of somites 1–5 darker; telson and uropods reddish. Antennular peduncle red, becoming paler proximally on article 1; flagella uniformly red. Antenna red, basicerite paler. Pereopods 1–5 white on outer side, red on inner side.

Variation. The sequential change with growth seen in the pleopods 1 and 2 strongly suggests that Pandalopsis princeps n. sp. is also a protandrous hermaphrodite as in other species of Pandalopsis . Like other congeneric species ( Komai 1994; this study), the rostrum of P. princeps n. sp. tends to become proportionally shorter with increase of size ( Fig. 14 View FIGURE 14 ); the ratio of the rostral length against the carapace length is 1.2–1.3 in the female stage.

Distribution. Presently known only from Nemuro Strait, at depth of 600 m.

Remarks. As mentioned above, Pandalopsis princeps n. sp. is morphologically most similar to P. capillus n. sp. This new species is distinguished from P. capillus n. sp. by the following particulars: the rostral lateral carina is sharply delimited over the entire length in P. princeps n. sp. ( Fig. 11B View FIGURE 11 ), whereas it becomes obsolete in the distal half in P. capillus n. sp. ( Fig. 2B View FIGURE 2 ); the postrostral spines are more numerous in P. princeps n. sp. than in P. capillus n. sp. (five to seven versus four or five); the setae scattered on the carapace surface are less conspicuous in P. princeps n. sp. than in P. capillus n. sp. ( Fig. 11A View FIGURE 11 versus Fig. 2A, B View FIGURE 2 ); the distolateral spine of the antennal scale is longer and more slender in P. princeps n. sp. than in P. capillus n. sp. ( Fig. 11F View FIGURE 11 versus Fig. 2G View FIGURE 2 ). The colouration in life is considerably different between the two species. In P. princes n. sp., the carapace is whitish translucent, and the rostrum is red; pleon is mottled with red, with the posterior edges of the somites 1–5 being darker; the pereopods 3–5 are white on the lateral surfaces and red on the mesial surfaces ( Fig. 10B View FIGURE 10 ). On the other hand, in P. capillus n. sp., the body and pereopods 3–5 are generally vermillion ( Fig. 1A, B View FIGURE 1 ).