Processa hayashii, Komai, Tomoyuki & Fujita, Yoshihisa, 2014

Komai, Tomoyuki & Fujita, Yoshihisa, 2014, New records of the caridean shrimp genus Processa Leach, 1815 (Crustacea: Decapoda: Processidae) from Japan, with descriptions of two new species, Zootaxa 3794 (2), pp. 263-278 : 273-277

Processa hayashii n. sp.

New Japanese name: Kubomi-rousoku-ebi ( Figs. 3 B, 7–9)

Material examined. Holotype: Ohura Bay, Nago, Okinawa Island, muddy-sandy bottom, 5–20 m, 21 June 2009, SCUBA diving at night, coll. Y. Fujita, 1 female (cl 4.8 mm), RUMF-ZC-2653.

Paratype: Ginowan, Okinawa Island, 17 m, 2 July 2011, SCUBA diving, coll. R. Minemizu, 1 ovigerous female (cl 4.3 mm), CBM-ZC 12298; Awa, Nago, Okinawa Island, 2–10 m, 11 July 2013, SCUBA diving, coll. S. Komai, 1 male (cl 2.7 mm), CBM-ZC 12299.

Description. Body ( Fig. 3 B) moderately slender.

Rostrum ( Fig. 7 A–C) slender, slightly curving downward, slightly falling short of or reaching to distal corneal margins; apex bifid, ventral tooth distinctly longer than dorsal tooth, bifurcation partially obscured by tuft of some short setae; ventral margin slightly sinuous, concave distally and convex proximally. Carapace ( Fig. 7 A, B) with suborbital angle well delineated, rounded; antennal tooth conspicuous; deep concavity present just superior to antennal tooth; pterygostomial angle obtuse.

Female thoracic sternite 7 ( Fig. 7 D) with low transverse crest divided in 2 parts by median notch. Thoracic sternite 8 ( Fig. 7 D) with obliquely transverse crest interrupted medially.

Pleon ( Fig. 3 B) smooth, almost glabrous, ventral margins of pleura lined with fine setae. Fifth pleomere ( Fig. 7 E) without posteroventral tooth on pleuron. Sixth pleomere ( Fig. 7 E) about 1.3 times as long as fifth pleomere, with subacute posteroventral tooth; posterolateral process rounded, unarmed. Sternites 1–5 unarmed.

Telson ( Fig. 7 E, G) 1.5 times as long as sixth pleomere, length 3.6 times greatest width, with 2 pairs of dorsolateral and 2 pairs of posterior spines; dorsal surface with transverse row of short to long setae anterior to anterior pair of dorsolateral spine and longitudinal row of moderately short setae in line with dorsolateral spines and longitudinal row of setae on either side of midline; anterior pair of dorsolateral spines located at about anterior 0.15 of telson length, posterior pair slightly posterior to midlength; distance between anterior (proximal) margin and anterior pair of spines about 2.5 of distance between pairs of spines; posterior spines with inner spine about 3 times of outer spine; apex produced into sharp tooth flanked by pair of long stiff plumose setae ( Fig. 7 H).

Eye ( Fig. 7 A, C) large, slightly depressed dorsoventrally, corneal width subequal to length of eyestalk and cornea combined, about 2.2 of greatest width of antennal scale.

Antennular peduncle ( Fig. 7 A, C) extending by two distal segments and 0.3–0.4 of proximal segment beyond rostrum, slightly overreaching distal margin of antennal scale, proximal segment slightly longer than distal two segments combined; ultimate segment about 0.6 length of penultimate segment; penultimate segment about 3.7 times as long as basal width; proximal segment with ventral tooth located slightly distal to midlength. Stylocerite ( Fig. 7 I) subtruncate distally with distomesial angle slightly produced, blunt; no dorsolateral angle delimited. Outer antennular flagellum with proximal thickened portion consisting of 12 or 13 articles (except for proximal 3 or 4 articles, bearing aesthetascs), distal slender portion consisting of 1 or 2 articles; inner flagellum almost twice as long as carapace.

Antennal scale ( Fig. 7 C) 5.6 times as long as wide; distolateral tooth overreaching roundly truncate distal margin of blade. Basicerite with distinct ventrolateral distal tooth ( Fig. 7 A). Carpocerite ( Fig. 7 A) reaching midlength of antennal scale. Flagellum exceeding 6 times of carapace length.

Mouthparts typical of genus, as figured ( Fig. 8 A–G). Mandible with row of minute spinules on posterior margin ( Fig. 8 A). Maxilla ( Fig. 8 D) with endopod tapering distally in acute tip.

Third maxilliped ( Fig. 9 A) overreaching antennal scale by length of ultimate segment. Ultimate segment about 1.2 times as long as penultimate segment (= carpus), tapering to sharp, spine-like apex distally; dorsal margin slightly sinuous; mesial surface with grooming apparatus consisting of several transverse or obliquely transverse tracts of stiff setae and some movable spines or spinules adjacent to dorsal margin. Antepenultimate segment distinctly longer than distal two segments combined; proximal 0.3 of dorsal margin shallowly excavated. Exopod reaching beyond proximal 0.3 of antepenultimate segment.

Left first pereopod ( Fig. 9 B, C) non-chelate, slightly longer and slenderer than right, reaching to distal margin of antennal scale by tip of dactylus; dactylus hook-like, about 0.2 times as long as propodus; propodus tapering distally, about 4.2 times as long as greatest width, with row of prominent tufts of setae on flexor margin; carpus shorter than propodus; merus distinctly longer than propodus and carpus combined, with row of setae on ventral margin. Right first pereopod ( Fig. 9 D, E) chelate, moderately stout, not reaching distal margin of antennal scale; chela about 4.0 times as long as wide; fingers about 0.6 length of palm; carpus distinctly shorter than palm; merus slightly tapering distally and proximally, subequal in length to chela and carpus combined.

Second pereopods ( Fig. 9 F, G) symmetrical, subequal in length, reaching base of antennal carpocerite by merocarpal articulation; ischium slightly shorter than merus, not divided, with distinct proximal lobe on ventral margin; merus divided into 4 or 5 articles; carpus divided into 13 articles; fingers subequal in length to slightly longer than palm.

Length of third to fifth pereopods: fourth>fifth>third ( Fig. 9 H, J, L); length ratio of dactyli 1: 1.2: 1.3 from third to fifth. Third pereopod ( Fig. 9 H) moderately long and slender, overreaching antennal scale by length of dactylus and propodus; dactylus ( Fig. 9 I) slightly curved, simple, about 0.3 times as long as propodus, with apical setae; propodus subcylindrical, unarmed; carpus about 1.7 times as long as propodus, unarmed; merus about 12 times longer than wide, armed with 5 movable spines on lateral surface; ischium distinctly shorter than merus, with 2 movable spines on lateral surface ventrally; combined lengths of propodus and carpus subequal to that of merus and ischium. Fourth pereopod ( Fig. 9 J) overreaching antennal scale by length of dactylus and 0.4 of propodus; dactylus ( Fig. 9 K) about 0.3 times as long as propodus; propodus subcylindrical, unarmed; carpus 1.7 times as long as propodus, also subcylindrical, unarmed; merus with 4 movable spines on lateral surface; ischium distinctly shorter than merus, with 2 movable spines on lateral surface ventrally. Fifth pereopod ( Fig. 9 L) not particularly elongate, but distinctly slenderer than preceding pereopods, overreaching antennal scale by length of dactylus and propodus; dactylus ( Fig. 9 M, N) slender, simple, about 0.3 times as long as propodus, with apical setae; propodus ( Fig. 9 N) with prominent tufts of setae terminally and with 4 widely spaced, slender spinules on flexor margin, including one at flexor distal angle; carpus about 1.2 times as long as propodus, unarmed; merus about 15 times as long as distal width, unarmed; ischium distinctly shorter than merus; combined lengths of propodus and carpus slightly greater than that of merus and ischium; coxa without peculiar lobe at mesial side in female.

Endopod of male first pleopod ( Fig. 7 K) about half length of exopod, subovate, without differentiated lobe on mesial or distomesial margin; margins sparsely setose. Appendix masculina on endopod of male second pleopod exceeding twice length of appendix interna ( Fig. 7 L), falling short of tip of endopod, bearing 2 apical setae and row of 5 very short setae on mesial margin. Uropodal exopod ( Fig. 7 G) exceeding beyond apex of telson, with suture at level of posterolateral denticle; lateral margin faintly sinuous, terminating in distinct acute tooth, with much stronger mesial movable spine; dorsal surface with few short setae adjacent to lateral margin. Uropodal endopod ( Fig. 7 G) slightly shorter than exopod, but still exceeding apex of telson; dorsal surface with numerous scattered, erect setae.

Coloration in life. Body and appendages generally translucent. Carapace with red chromatophores along orbital margin and with few white dots on lateral surface. Pleon with some white spots on pleura. Cornea light gray. Antennular peduncle with white spots at base of penultimate segment and base of flagella. Antennal basicerite with tint of red. Third maxilliped generally pale red, with large white spot at midlength of antepenultimate segment. First pereopod with dactylus to carpus reddish, merus to ischium translucent. Second to fifth pereopods translucent. Protopods of uropods with tint of red. Telson and uropods whitish, exopod with tinge of brown laterally. See Fig. 3 B.

Distribution. Presently known only from Okinawa Island, Ryukyu Islands, Japan, 5– 20 m.

Remarks. The present new species is referred also to the P. aequimana species group on account of the unarmed fifth pleuron and subequal second pereopods. The presence of a normally developed antennal tooth on the carapace, the unarmed posterolateral process of the sixth pleomere and the unarmed antennular stylocerite with a mesially produced apex distinguish P. hayashii n. sp. from all but P. moana . Because of the insufficient published descriptions, characters of the sixth pleomere and antennular peduncle remain unknown for P. moana , but P. hayashii n. sp. differs from P. moana in the rostrum not reaching beyond the distal corneal margins (versus slightly overreaching the distal corneal margins) and the possession of four spinules on the flexor margin of the propodus of the fifth pereopod (versus unarmed) ( Yaldwyn 1971). Finally, the presence of a deep concavity on the anterior margin of the carapace, just above the antennal tooth, seems to be characteristic to P. ha y a s hi i n. sp.

Processa hayashii n. sp. is also similar to P. filipes n. sp., but as mentioned above, the latter new species is quite characteristic in having a greatly elongate, extremely thin fifth pereopod and the somewhat thickened, noninterrupted, membranous transverse ridge on thoracic sternite 8. The less acute posteroventral tooth of the sixth pleomere and the possession of flexor spinules on the propodus of the fifth pereopod also distinguish P. h ay a s h i i n. sp. from P. filipes n. sp.

Etymology. It is our pleasure to dedicate this new species to Dr. Ken’ichi Hayashi, Professor Emeritus of the National Fisheries University, Shimonoseki, in recognition of his immense contributions to the taxonomy of Caridea, in particular Processidae in the Indo-West Pacific.

Figures

FIGURE 7. Processa hayashii n. sp. A – J, holotype, ovigerous female (cl 4.8 mm), RUMF-ZC- 2653; K, L, paratype, male (cl 2.7 mm), CBM-ZC 12299. A, carapace and cephalic appendages, lateral view; B, rostrum and anterior part of carapace, lateral view; C, anterior part of carapace and cephalic appendages, dorsal view (marginal setae on antennal scales omitted); D, transverse ridges on thoracic sternites 7 and 8, ventral view (coxa of right fifth pereopod shown); E, fifth and sixth pleomeres and telson, lateral view; F, posterior margin of sixth pleomere, lateral view; G, telson and right uropod, dorsal view; H, posterior part of telson, dorsal view; I, stylocerite of left antennular peduncle, dorsal view (setae omitted); J, distal part of left antennal scale, dorsal view (setae omitted); K, endopod of left first pleopod, ventral view; L, appendices interna and masculina of left second pleopod, mesial view. Scale bars: 1 mm for A, C, E; 0.5 mm for B, D, F – L.

FIGURE 8. Processa hayashii n. sp., holotype, female (cl 4.8 mm), RUMF-ZC- 2653, left mouthparts. A, mandible, outer view; B, same, inner view; C, maxillule, outer view; D, maxilla, outer view; E, first maxilliped, outer view; F, same, inner view (setae omitted); G, second maxilliped, outer view. Scale bars: 0.5 mm.

FIGURE 9. Processa hayashii sp. n., female (cl 4.8 mm), RUMF-ZC- 2653. A, left third maxilliped, lateral view; B, left first pereopod, lateral view; C, same, dactylus and propodus, mesial view; D, right first pereopod, lateral view; E, same, chela, extensor view; F, left second pereopod, lateral view; G, right second pereopod, lateral view; H, left third pereopod, lateral view; I, same, dactylus, lateral view; J, left fourth pereopod, lateral view; K, same, dactylus, lateral view; L, left fifth pereopod, lateral view; M, same, dactylus, lateral view; N, same, dactylus and propodus, lateral view (perpendicular). Scale bars: 1 mm for A, B, D, F – H, J, L; 0.5 mm for C, E, I, K, M, N.

FIGURE 3. A, Processa filipes n. sp., holotype, ovigerous female (cl 4.4 mm), RUMF-ZC- 2652. B, Processa hayashii n. sp., holotype, female (cl 4.8 mm), RUMF-ZC- 2653. Entire animals, lateral view, showing coloration in life.