Juxtastenopus spinulatus ( Holthuis, 1946 ) Goy, 2010

Goy, Joseph W., 2010, A review of the genus Engystenopus (Crustacea: Decapoda: Stenopodidea) Juxtastenopus, gen. nov., a new combination for E. spinulatus Holthuis, 1946, and transfer of E. palmipes Alcock & Anderson, 1894 to the family Spongicolidae Schram, 1986 *, Zootaxa 2372, pp. 263-277 : 265-273

Juxtastenopus spinulatus ( Holthuis, 1946) comb. nov.

( Figs. 1–5)

Stenopus spinosus — Balss 1914: 137 (nec Stenopus spinosus Risso, 1826 ). — Balss 1915: 33 (nec Stenopus spinosus

Risso, 1826). — Balss 1929: 25, 26, 27 (nec Stenopus spinosus Risso, 1826 ).? Engystenopus spinulatus — Holthuis 1946: 45, pl. IV figs. a, b. Engystenopus spinulatus — Burukovsky 1974: 93. — Lewinsohn & Holthuis 1978: 229, fig. 1. — Burukovsky 1983:

132. — Goy 1986: 211-216, fig. 1. — Türkay 1996: 48, fig. 5.

Material examined. (i) 1 male holotype, cl 8.8, Siboga Expedition Station 306, Indonesia, Lobetoli Strait, East of Flores, 8 o 27’S, 122 o 54.5’E, 247 m, sandy mud, also in 29 m, Lithothamnion , 8.II.1900, ZMA. (ii) 1 male, cl 6.4, taken from stomach of a golden threadfin bream ( Nemipterus virgatus ) caught in the Indian Ocean at 40–100 m and found in the Hong Kong fish market, leg. A. J. Bruce, MNHM. (iii) 1 male, cl 5.2, SLR1699, Decapoda 222, Hebrew University of Jerusalem, Marsat Abu Samara , Red Sea, Israel; Gulf of Eilat, 20 o 16.5’N, 34 o 47’E, 604 m, 30. V. 1968, RMNH D41305. (iv) 1 ov. female, cl 7.3, R. V. “ Valdiva I” StationVA22-111 TA , ST-235, closing trawl, Central Red Sea, 21 o 28.97’N, 38 o 15.55’E, 740–785 m, 12.IV.1979, SMF 12340. (v) 1 female, cl 5.2, R. V . “Sonne” Station SoO2-27 TA , ST-202, closing trawl, Red Sea, Ras Abu Shagara , 21 o 10.8’N 37 o 34’E, 733–757 m, 19.X.1977, SMF 27871. (vi) 1 ov. female, 3 females, cls 6.7, 7.1, 5.2, 5.9, R. V . “Meteor” Station Me 5-96 KU , beam trawl, Red Sea, off N. Sudan, 22 o 04.2’N, 37 o 10’E to 22 o 05’N, 37 o 09.3’E, 600 m, 9. II. 1987, SMF 27872. (vii) 2 males, 4 females, cls 6.0, 7.0, 7.7, 7.0, 6.0, 6.2, R. V . “Meteor” Station Me 5-148 KU , beam trawl, Red Sea, off Port Sudan, 19 o 43.3’N, 37 o 40.5’E to 19 o 44.5’N, 37 o 40.2’E, 517–583 m, 20. II. 1987, SMF 27874. (viii) 3 females, cls 6.6, 6.6, 5.7, R. V . “Meteor” Station Me 5-171 KU , beam trawl, Red Sea, off S. Sudan, 18 o 34.5’N, 39 o 02.4’E to 18 o 35.3’N, 39 o 03.5E, 434– 469 m, 23. II. 1987, SMF 27875. (ix) 1 female, cl 6.4, R. V . “Meteor” Station Me 5-172 KU , beam trawl, Red Sea, off S. Sudan, 18 o 34.8’N, 39 o 03.2’E to 18 o 34.7’N, 39 o 01.9’E, 428–459 m, 23. II.1987, SMF 27876. (x) 1 ov. female, 2 females, cls 7.6, 7.5, 4.6, R. V . “Meteor” Station Me 5-193 KU , beam trawl, Red Sea, N. of Masamirit , 19 o 24.3’N, 38 o 31.2’E to 19 o 25.5’N, 38 o 30.9’E, 696–705 m, 28. II. 1987, SMF 27877. (xi) 1female, cl 6.6, R. V . “Meteor” Station Me 5-194 KU , beam trawl, Red Sea, N. of Masamirit , 19 o 18.2’N, 38 o 15.5’E to 19 o 18.2’N, 38 o 14.8’E, 537–681 m, 28. II. 1987, SMF 27878. (xii) 1 female, cl 7.3, R. V . “Meteor” Station Me 5-197 KU , beam trawl, Red Sea, off Port Sudan, 19 o 52.2’N, 37 o 35.3’E to 19 o 53.4’N, 37 o 35.1’E, 747–778 m, 1. III. 1987, SMF 27879. (xiii) 1 ov. female, 1female, cls 6.1, 6.2, R. V . “Meteor” Station Me 5-281 KU , beam trawl, Gulf of Aden , 12 o 38.5’N, 45 o 28.5’E to 12 o 38.7’N, 45 o 28.8’E, 1063–1068 m, 15. III. 1987, SMF 27880. (xiv) 1 male, cl 6.5, “PANGLAO” Station CP2377, Philippines, 8 o 40.6’N 123 o 20.3’E, 82.4–85.3m, 28. V. 2005, NTOU M00788 .

Diagnosis. As for the genus.

Redescription. A slender stenopodid shrimp with a compressed body form.

Rostrum ( Fig. 1) moderately long, reaching slightly past antennular peduncle; narrow, laterally compressed, slender, usually straight, but sometimes slightly upturned at tip. Dorsal margin bearing 7–12 teeth, ventral margin with 2–7 teeth; no lateral teeth; dorsal margin continuing as postrostral ridge behind orbit up to cervical groove bearing 6–10 pairs of spines.

Carapace ( Figs. 1, 2A) with strong antennal, branchiostegal, hepatic, and pterygostomial spines. Cervical groove very deep with 10–14 spines along posterior margin, running obliquely forward and downward, ending in spine lying directly behind antennal spine. Fairly large supraorbital spine, few spines and spinules in triangular area between dorsal carapacial margin, orbit and cervical groove. Median dorsal margin behind cervical groove bears 3 or 4 rows of 6-12 spines just before posterior margin. Lateral surface with spines arranged in number of longitudinal rows; before posterior margin bearing in each half transverse row of 6 or 7 spines.

Pleon ( Figs. 1, 2B–D) with transverse groove on first pleomere, behind which, 7–10 spines, 3 or 4 spines anterior to groove; pleuron ending in tooth preceded by rectangular or rounded lobe. Transverse grooves present on second and third pleomeres bearing row of spines; another spinous row on anterior margins of these pleomeres. Tergum of third pleomere with 5 or 6 large forwardly directed spines; few spinules. Distal pleural margins of second to fourth pleomeres ending in 3 sharp teeth, while fifth pleomere ending in 2 or 3 teeth. Fourth pleomere with smooth tergum, two oblique rows of 4–7 spines on lower pleural margin below which are additional 1 or 2 spines. Pleuron of fifth pleomere narrowing distally, bearing 1 or 2 oblique rows of 4–6 spines, posterior row merging with groove on tergum. Sixth pleomere almost twice as long as fifth, bearing medial tranverse groove with row of 4–8 posteriorly directed spines; similar transverse row of 6 or 7 spines anterior to posterior margin. Strong spine located in lower anterior of sixth pleomere just behind pleuron of fifth pleomere; a few smaller spines scattered nearby. Pleuron of sixth pleomere ending in acute tooth over base of uropod, with blunt triangular tooth medially. Sixth sternite of male with pair of triangular lobes, each distal angle produced with 1 or 2 spines, each lateral margin with spine; seventh and eighth sternites with pair of broad, trapezoid lobes with 4 and 3 spines respectively on lateral and anteromesial margins. Sternites of first five pleomeres in males with median ventral spine. Sixth to eighth sternites of female unarmed, more rectangular, not much wider than those of male.

Telson ( Figs. 2B, 4D) lance-shaped, slightly longer than sixth pleomere with median groove flanked by two longitudinal carinae bearing 6–8 posteriorly directed spines. Strong anterior spine present laterally at base of telson, with 2 rows of 4–6 median spines along margin of each longitudinal carina extending slightly less than half way down length of telson. Each lateral margin bearing distinct tooth at midlength, provided with numerous long plumose setae along posterior three-fifths. Posterior margin somewhat rounded ending in 2 acute posterolateral teeth, smaller acute median denticle.

Eye ( Figs. 1, 3A) well developed, with peduncle slightly longer than pigmented cornea. Dorsal surface of peduncle bears 5 or 6 spines near base of cornea, anterior margin with 2–3 more spines.

Antennule peduncle ( Figs. 2A, 3D) short, extending to middle of scaphocerite; proximal segment longest with broad, subrectangular process on inner proximodorsal margin, short, acute stylocerite proximally and small plumose lobe distally on outer margin; middle segment slightly shorter than proximal segment with 2–4 small spines on distodorsal margin; distal segment shortest with distodorsal spine. Upper and lower flagella well developed, extending almost to tip of telson.

Antenna ( Figs. 2A, 3E) with large basicerite, with 3–5 spines; scaphocerite 4 times as long as wide, lateral margin concave proximally, armed with 1 or 2 small teeth; 0.75 of distal length with 6–14 teeth including terminal tooth. Dorsal surface of scaphocerite with 2 distinct longitudinal carinae, no spinules; ventral surface unarmed. Flagellum well developed extending beyond tip of telson.

Epistome ( Fig. 3C) anteriorly triangular with 2 long submedian spines, smaller spines laterally; labrum normally developed; paragnath shaped like arrowhead, with narrow median fissure.

Mandible ( Figs. 3F–G) robust, with short, fused molar and incisor processes. Molar surface nearly smooth; incisor bearing large, rounded tooth on each end, 8 smaller sharp teeth in between. Palp welldeveloped, 3-segmented, segments of subequal length; proximal segment glabrous, middle and distal segments setose.

Maxillule ( Fig. 3H) with slender, undivided endopod bearing plumose seta laterally, 5–6 setae distally. Proximal endite moderately broad, truncate distally, with numerous distal compound spinose and plumose setae. Distal endite of subequal size, rounded distally, with numerous plumose setae.

Maxilla ( Fig. 3I) with numerous plumose setae on both lobes of coxal and basal endites, proximal lobe of coxal endite broadest. Endopod long, slender, exceeding anterior margin of scaphognathite, with 10–12 lateral, 12 or 13 distal, and 6 or 7 inner marginal plumose setae. Scaphognathite long, narrow, about 4 times longer than maximal width with numerous plumose setae along margin.

First maxilliped ( Figs. 3J, 4A) with 3-segmented endopod; proximal segment longer than wide, with 10– 18 long plumose setae laterally along outer margin, inner margin with 3–5 short plumise setae; middle segment 0.5 length of proximal with 12–14 long plumose setae along outer margin; distal segment slender, tapering about 0.5 length of middle with short simple terminal seta. Basipodite large, acutely rounded anterior, concave middle, rounded posterior, bearing dense fringe plumose setae; coxapodite bilobed, each lobe with numerous short plumose setae. Exopod well-developed, flagellum with 6 or 7 long simple proximal setae, 20– 25 long plumose distolateral setae. Large epipod with slender proximal and distal lobes of equal length.

Second maxilliped ( Figs. 3K, 4B) with 4-jointed endopod; dactylus suboval, longer than broad. With dense fringe of short setae along distodorsal margin; propodus slightly longer than dactylus densely setose on dorsal margin, ventral margin bearing acute proximal tooth; carpus short, narrow, 0.5 propodal length, with 5 or 6 long simple setae at distodorsal angle, 0–4 distomesial short setae, 2 or 3 short setae on ventral margin; merus slightly more than 2 times dactylar length, 2.5 times longer than broad, dorsal margin with 9 short simple setae, ventral margin convex with fringe of numerous long simple setae; ischium fused to basis, both lobate with dense fringe of short setae; coxa unarmed. Exopod long, slender, undivided with distal 0.5 bearing 20–25 plumose setae; small elongate epipod present; arthrobranch and podobranch also present.

Third maxilliped ( Figs. 3L, 4C) with 7-segmented endopod; dactylus, propodus and carpus subequal in length, with numerous long plumose setae; propodus bears weak setiferous organ at distomesial angle while distal extremity of outer margin of carpus with acute spine; merus longest, widest segment with 4–8 outer marginal spines, one specimen with 9 spines on inner margin, holotype with row of 13 small spines near outer margin; numerous long plumose setae on dorsal and ventral margins; ischium slightly shorter than merus with 2–5 outer marginal spines, holotype with 6 spines on inner margin, numerous long plumose setae on inner margin; basis and coxa short unarmed; exopod long, setose.

First pereiopod ( Figs. 1, 4E) smallest, shortest cheliped; chela slender, long with fingers and palm subequal in length, with palm slightly swollen, cutting edges provided with small stout peglike denticles separated by rectangular chitinous lamellae. Fingers bearing small tufts of long setae; distoventral part of carpus and distoproximal part of propodus bearing weak setiferous organ composed of stout serrate setae, few long plumose setae; rest of pereiopod glabrous, unarmed. Carpus longest segment, 1.2 times meral and ischial length.

Second pereiopod ( Fig. 1) more robust than first pereiopod, longer, tips of fingers more strongly hooked than first, with small tufts of long setae; cutting edges of chela similar to those of first. Carpus longest segment nearly twice propodal length, bearing 2–4 spinules on dorsal margin; merus same length as propodus with spinule about midway on dorsal margin; ischium unarmed, short, 0.5 times meral length.

Third pereiopod ( Figs. 1, 4F–G) strongest, robust, slightly longer than entire body length; propodus, carpus, merus subequal in length. Palm with dorsal row of 7–20 spinules above one or two rows of 10–13 spinules on outer side; ventral margin bearing 9–12 spinules above row of 3 or 4 spinules; few long simple setae between dorsal, ventral marginal spinules. Fingers, elongate with sharp hooked crossing tips, distally bearing short tufts of simple setae. Dactylus with 2–5 spinules on dorsal margin; cutting edge with proximal chitinous ridge, large rounded or subrectangular tooth merging row 18–20 small, stout, peg-like teeth separated by rectangular lamellae. Cutting edge of fixed finger with proximal chitinous ridge bearing large blunt tooth, sharp triangular tooth opposing dactylar tooth, merging into 16 peg-like teeth separated by chitinous lamellae. Carpus slightly widened distally, dorsal margin with 12–15 strong spines above row of 6 or 7 smaller spines, ventral margin with 7–9 spines; merus with 6–12 spines on dorsal margin above row of 4– 7 smaller spines, ventral margin with 6–9 spines; ischium shortest segment with 1–7 spines on dorsal margin. Fourth and fifth pereiopods ( Fig. 1) long, slender, very similar; fourth slightly longer than fifth. Dactylus uniunguiculate, slender, sharply pointed, about 0.25 propodal length. Propodus subdivided into 6–8 distinct segments bearing 5–7 ventral movable spines; carpus 3 times longer than propodus indistinctly subdivided into 14–18 segments, lacking ventral movable spines; merus about 0.6 length of carpus, wider, subdivided into 2 or 3 indistinct segments; ischium subequal to length of propodus.

Pleopods without appendices internae; first shortest, uniramous; second to fifth biramous; ventral margin of basipodites armed with 0–3, 3–4, 4, 4–5, and 2–4 spinules, respectively.

Uropod ( Figs. 3B, 4D) slightly shorter than telson; protopodite stout, with short rounded tubercle located proximomesial. Exopod wider than endopod with 9–15 acute teeth on outer margin; dorsal surface with 2 longitudinal carinae and small proximal spine near outer margin. Endopod with 2–8 teeth on outer margin, 2 longitudinal carinae, 1 sometimes indistinct, row of 3–7 small spines adjacent to lateral margin.

Measurements. (mm) Postorbital carapace length: females 4.6–7.7, males 5.2–8.8; carapace and rostrum length: females 7.4–12.7, males 7.5–10.2; total body length: females 17.4–28.0, males 19.8–24.6.

Colour pattern. ( Fig. 5) Color notes of Dr. Türkay on board R.V. Meteor for an ovigerous female from Station 96 and a male from Station 148: carapace, abdomen, uropods, meri of second to fifth pereiopods, basal segments of antennae and antennulae densely covered with light red pigment spots, which gives the whole animal a pink appearance. Carpi, propodi and dactyli of second to fifth pereiopods transparent. Telson, scaphocerite and all segment of third maxillipeds with pink lines along their outer borders, otherwise scarcely pigmented. Sternum with few light red pigment blotches, eggs blue-green. Male similar in coloration to female, but third pereiopods were pink accept the tips of the chela fingers were white. Color notes of the Philippine male specimen is through the courtesy of Dr. Chan: In life, body generally red. Rostrum, carapace and pleon red. Telson and uropods red; eye stalk transparent, but spines red; antennal scale transparent, except red dorsal carinae, red lateral and mesial margins; third maxilliped red, first pereiopod transparent; second pereiopod red, but chela and distal part of carpus transparent; third pereiopod red but finger tips of chela white; fourth and fifth pereiopods red, but carpal-meral joint and distal 0.75 of dactyli transparent.

Development. Ovigerous females ranged in size from 6.1–7.6 mm postorbital carapace length, 22.1–26.5 mm tl, and carried 27– 132 eggs. Eggs at blastula stage with undifferentiated yolk cells were 0.30 × 0.49 mm in size, while eggs with embryos having pigmented eyes and well developed appendages were 0.60 × 0.80 mm in size.

Distribution. Indonesia, Red Sea, Gulf of Aden, Philippines; 82–1068 m. Most specimens have been collected throughout the Red Sea at depths of 434 to 778 m, which corresponds to the warm deep Red Sea water mass. The outflow of this deep warm water of the Red Sea sinks to around 1000m south of the Straits of Bab el Mandeb into the Gulf of Aden where one specimen of J. spinulatus was collected at a depth of 1068 m. Outside the Red Sea basin, this species has been collected in the Indian Ocean, Indonesia and the Philippines at much shallower depths. The Indonesian holotype was collected at a depth of 247 m, but the label states also in 29 m, Lithothamnion . The Hong Kong specimen was taken from the stomach of Nemipterus virgatus , a demersal fish commonly caught at depths of 18–33 m ( Russell, 1990), while the specimen from the Philippines was found at 82.4–83.5 m.

Remarks. Juxtastenopus spinulatus comb. nov. was originally described based only on one mutilated male specimen from Indonesia ( Holthuis, 1946). Later, Lewinsohn & Holthuis (1978) added detailed descriptions of a male and an ovigerous female from the Red Sea originally thought to be Stenopus spinosus ( Balss 1914, 1915, 1929). The fourth known representative of this species, an ovigeous female, was described by Goy (1986). All of these specimens were lacking the third pereiopods, so they were tentatively placed in the genus Engystenopus . The genus Engystenopus was established by Alcock & Anderson (1894) for a unique specimen of E. palmipes collected in the Bay of Bengal, off Trincomallee with a more thorough description of the species given later by Alcock (1901). Fifteen additional specimens were collected from the Philippines and a more thorough description as well as morphological variation was provided by de Saint-Laurent & Cleva (1981), who felt that E. spinulatus belonged to a different, new genus. In the present paper, an additional 7 specimens of E. palmipes were examined, as well as three specimens of E. spinulatus with intact third pereiopods, leading to the designation of the new genus Juxtastenopus .