Odontozona joegoyi Hendrickx & Ayón-Parente, 2014, n. sp.

Odontozona joegoyi n. sp.

(Figs. 1–4)

Type material. HOLOTYPE: male, CL 4.9 mm, TL 16.9 mm, TALUD XV cruise, St. 1 (23°18'40"N, 111°19'37"W), 4 August 2013, benthic sledge, 750–850 m depth (EMU-10079).

ALLOTYPE: female, CL 4.9 mm, TL 19.8 mm, same station (EMU-10080); paratype, male, CL 3.6 mm, same station (EMU-10081).

PARATYPES: female, CL 3.9 mm, same station (EMU-10082); male, CL 4.9 mm, TL 15.6 mm (EMU- 10083).

Additional material. Two males, lacking third pereiopods, CL 3.1, TL 13.3 mm and CL 3.6 mm, TL 19.8 mm, TALUD XV cruise, St. 1 (23°18'40"N, 111°19'37"W), 4 August 2013, benthic sledge, 750–850 m depth (EMU- 10084); 7 males, lacking third pereiopods, same station, CL 3.6–4.4 mm, TL 13.7–18.1 mm (EMU-10085); one female, lacking third perieopods, CL 6.5 mm, TL 20.5 mm, TALUD XV cruise, St. 5d (23°16'58"N, 110°20'42"W), 5 August 2013, benthic sledge, 650–665 m depth (EMU-10086).

Diagnosis. Carapace with cervical groove well-marked, posterior margin of groove with cincture of 28–32 spines; no spine on dorsal and posterior parts of carapace; anterior margin with numerous spines below the antennal spine. Third pereiopods relatively slender, outer face of palm with numerous minute spines. Abdominal somites without grooves; ventral margin of pleura 1–5 spinulose; lateral face of somite 6 with a vertical series of 4 spines. Telson with a pair of lateral and a pair of distal spines, two series of dorsal spines longitudinally, parallel to lateral margin, and some additional median spines in proximal half.

Description. Based on holotype (EMU-10079). Rostrum (Fig. 1 A) compressed, blade-like, deep, almost straight, reaching end of penultimate segment of antennular peduncle and a little over proximal 1/3 of scaphocerite length; dorsal margin armed with 13 small, equally spaced teeth, the posterior 3 situated posterior to hind margin of orbit, ventral margin with 3 teeth, the most proximal distinctly larger than anterior 2 (Fig. 1 A). Carapace with supraorbital and hepatic spines forming a triangular group of 3 strong spines; fourth, much smaller hepatic spine on left side (wanting on right side). Postrostral carina (Fig. 1 B) low, not reaching cervical grove; a series of 4 or 5 smaller spines slightly posterior to base of rostrum.

Carapace (Fig. 1 A, B) robust, with deep cervical grove armed on posterior margin with cincture of 30 medium-sized, anteriorly directed spines, all spines of subequal length; no groove or spines in posterior portion of carapace; antennal spine small; a pair of branchiostegal spines followed by a series of 8 small pterygostomial spines on each side of carapace.

Abdomen (Fig. 1 A) moderately robust, dorsally unarmed, without median carina or without transverse grooves. Margins of pleura 1–3 rounded, pleuron 1 unarmed, pleuron 2 with 3 anterior spines, pleuron 3 with 5 anterior and 2 posterior spines; margins of pleura 4–6 almost straight, pleuron 4 with 4 ventral and 3 posterior spines, pleuron 5 with one ventral and 2 posterior spines, pleuron 6 spineless; a vertical series of 4 spines on pleura of sixth somite. Telson 2.3 times as long as wide; 1 pair of strong lateral spines at about midlength and 1 pair of strong distal spines; 2 dorsolateral series of 7 spines parallel to lateral margins, and 2 or 3 pairs of mesiodorsal spines in proximal half (Fig. 1 E).

Eyes (Fig. 1 A, B) moderately large, cornea darkly pigmented; distal margin of peduncle with a row of 7 small spines along boundary with cornea, and cluster of 2–4 spines of equal size on dorsal surface.

Epistome (Fig. 2 H) with 2 pairs of sharp, slightly curved spines.

Antennular peduncle (Fig. 1 C) reaching midlength of scaphocerite; proximal segment long, with short, curved stylocerite proximally, anterior margin unarmed, 1 strong mesial spine on inner margin; middle segment about 0.5 of proximal, with 1 strong distal spine at outer margin, and 2 strong spines on inner margin; distal segment 0.5 of middle segment length, unarmed; upper and lower flagella about 1.5 times as long as carapace length.

Antennal peduncle (Fig. 1 D) with basal segment armed with 4 or 5 ventral spines; second segment with 2 small ventrodistal spines, scaphocerite lanceolate, outer margin with 4 or 5 lateral spines, distolateral spine exceeding beyond obliquely subtruncate lamella; third segment with 2 distal spines (right minute) and 1 large, mesial spine at midlength; flagellum about 3 times as long as carapace length.

Mouthparts as illustrated (Fig. 2 A–G), without distinctive features. Third maxilliped (Fig. 2 G) pediform, setose, moderately slender; basis with a well developed, 2–segmented exopod; ischium armed with 7 spines on ventral margin and 5 dorsolateral movable spinules; merus slightly shorter than ischium, 2 strong spines in distal half of ventral margin, 1 smaller distoventral spine, and 2 small spines on mesial face; carpus, propodus, and dactylus unarmed, carpus and propodus of subequal length, shorter than merus, dactylus 0.5 of merus length.

First pereiopod (Fig. 3 A) slender, all segments unarmed; merus about 1.5 times as long as ischium; carpus 1.3 times as long as merus; carpus and propodus with setiferous organ; fingers of equal length, about 0.5 length of palm, with some tufts of setae.

Second pereiopods (Fig. 3 B) similar to first in structure and proportion of segments, unarmed, about 1.6 times as long as first.

Third pereiopods (Fig. 4) the longest, subequal and similar, about 3.6 times length of carapace. Ischium ventrally armed with 5 minute spines. Merus with 4 short dorsal spines and 6 ventral spines, increasing in size distally. Carpus widening distally, armed ventrally with rows of about 10 minute spines, dorsally with 6 strong marginal spines and a series of 5 submarginal spines. Palm with scattered spinules on surface; fingers about 0.6 of palm length, elongated, with hooked, crossing tips; cutting edge of dactylus crested, with proximal tooth; cutting edge of pollex also crested, with proximal hiatus.

Fourth pereiopods (Fig. 3 C) long and slender, about 1.8 times as long as first; carpus subdivided in 5 articles; propodus subdivided in 4 segments ventrally armed with small movable spines; dactylus biunguiculate, unguis about twice as long as corpus.

Fifth pereiopods (Fig. 3 D) generally similar to fourth pereiopods, about 1.8 times as long as first, of same length as pereiopods 4; carpus subdivided in 5 segments; propodus subdivided in 4 segments, ventrally armed with small movable spines; dactylus biunguiculate, unguis about twice as long as corpus.

First pleopods uniramous (Fig. 3 E), others biramous.

Uropods (Fig. 1 E) shorter than telson; protopodite stout, ending with 6 distal teeth; exopod wider than endopod, with 8 teeth on outer margin; dorsal surface with 2 longitudinal carina; endopod unarmed, slightly longer than exopod, with 2 longitudinal carinae (Fig. 1 E).

Description of female. Similar to male. Third pereopods about 3.6 times length of carapace.

Colour pattern. Unknown.

Etymology. The new species is named after our colleague Joseph ("Joe") W. Goy, Harding University, in recognition of his extensive work on stenopodid shrimp from the East Pacific and elsewhere.

Distribution. Presently known only from two localities off the west coast of Baja California between 650 and 850 m depth. Environmental data recorded close to bottom at the sampling site are: 5.75–6.15 ºC; 0.08–0.11 mlO2/l.

Remarks. Some variations were observed among the material examined. The dorsal margin or the rostrum is armed with 13 small, equally spaced teeth, in the holotype, while this number varies from 12 to 14 in the other specimens. The cervical grove is armed on posterior margin with cincture of 30 medium-sized teeth in the holotype, and this number also varies from 28 to 36 in the other specimens. The pleuron 2 features 3 anterior spines in the holotype, but the small, posteriormost tooth is sometimes obsolete. The telson of the holotype has 2 pairs of mesiodorsal spines on one side and 3 on the other, and this is also variable with specimens featuring 2 + 2, 3 + 3 or 2 and 3 spines.

Compared to the other species of the genus occurring in the East Pacific, O. joegoyi n. sp. most closely resembles O. spongicola in lacking a transverse row of spinules posterior to the cervical cincture of spines. The new species, however, lacks a group of hepatic spines on the carapace, which is present in O. spongicola (see Goy 1992). The ventral margin of abdominal pleura 1–5 of O. joegoyi n. sp. bears spinules, while the margins of these pleura are smooth in O. spongicola, which is also characterized by a much stronger, heavy third pair of pereiopods compared to O. joegoyi n. sp. Compared to the two other species of Odontozona known from the East Pacific, O. joegoyi n. sp. is readily distinguished from O. foresti by its much smaller size (between 3.6 and 6.5 mm CL in O. joegoyi n. sp. vs. 16.5 mm CL in O. foresti), the absence of a strong, posterior cincture of stout spines on the carapace (formed of 6 or 7 stout spines on each side in O. foresti), and the numerous dorsal spines on the telson (no dorsal spines in O. foresti) (see Hendrickx 2002). Odontozona rubra, the third East Pacific species, also features a cincture of small spines posterior to cervical grove and spines on the mid carapace beyond the level of the orbit (Goy 1992) (no dorsal spines on carapace in O. joegoyi n. sp.).

Goy and Cardoso (2014) presented a key to all known species of Odontozona from the Atlantic Ocean (8 species in total). Of these, only two species lack spines behind the cervical groove, as in O. joegoyi n. sp.: O. edwardsii (Bouvier, 1908) and O. lopheliae Goy and Cardoso, 2014. The former is characterized by a cluster of spines behind the spinose anteroventral part of the carapace (no such cluster in O. joegoyi n. sp.), the merus of the third maxilliped is armed with 4 strong spines (vs. 3 small spines in O. joegoyi n. sp.), and the chela of the third pereiopods are armed with strong spines on the dorsal margin (no strong spines in O. joegoyi n. sp.) (Goy & Cardoso 2014). The latter features smooth ventral margins of abdominal pleura 2–5 (vs. spinose margins in O. joegoyi n. sp.) and the chela of the third pereiopods armed with strong spines on both the dorsal and ventral margins (Goy & Cardoso 2014) (both margins without strong spines in Odontozona joegoyi n. sp.).

The new species, however, shows some resemblance with O. edwardsii redescribed by Goy & Cardoso (2014), particularly compared to the male syntype; both species have a similar armature on the carapace, although in O. joegoyi n. sp. the cervical cincture is much shorter and does not extend beyond mid height of the carapace. Both species also have spiny ventral margins of abdominal pleura 2–5, although spines are fewer and stronger in O. edwardsii.

Among the rest of the known Pacific species of Odontozona, both O. spinosissima Kensley, 1981, and O. sculpticauda Holthuis, 1946, present grooves and ridges on the pleon (none in O. joegoyi n. sp.). Odontozona ensifera (Dana, 1852) has 3 parallel series of short spines on the posterior portion of the carapace (J.W. Goy, pers. comm., April 2014) (none in O. joegoyi n. sp.). Odontozona fasciata Okuno, 2003, inhabits relatively shallow waters (25–35 m depth) and is characterized by a spiny post-cervical groove, a long rostrum (as long as the carapace length) armed with widely-spaced, large dorsal and ventral teeth, and a single pterygostomian spine (Okuno 2003), all characters differing from what can be observed in O. joegoyi n. sp. (i.e., rostrum much shorter than carapace; rostrum with closely-set series of small dorsal spines; numerous spines at pterygostomian angle). Odontozona crinoidicola Saito & Fujita, 2009, is a shallow-water species (Saito & Fujita 2009) with a spiny postcervical groove (none in O. joegoyi n. sp.) and a proportionally much wider carapace (slightly wider than long in O. crinoidicola vs. less than 1.5 times as long as wide in O. joegoyi n. sp.).

In addition to O. spongicola (496–900 m depth) (Wicksten, 2012) and O foresti (1240–1270 m depth, but see below), both known from the East Pacific, deep-water species of Odontozona include O. edwardsi (511 to 2070 m), O. minoica Dounas & Koukouras, 1989 (330 m depth), and O. spinossissima Kensley, 1981 (150–200 m depth).