Pasiphaea antea, Rodrigues & Alves-Júnior & Cardoso, 2018

Rodrigues, Thaiana G. A., Alves-Júnior, Flavio A. & Cardoso, Irene A., 2018, A new species of Pasiphaea Savigny, 1816 (Crustacea, Decapoda, Pasiphaeidae) from the southwestern Atlantic, Zootaxa 4418 (5), pp. 493-498 : 494-498

PasIPHaea antea n. sp.

( Figures 1–3 )

Material examined: holotype: Abracos 2, station 47, Fernando de Noronha Archipelago (4° 25' 52'' S; 32°57' 51'' W), 30 April 2017, 1 ovigerous female (cl 42.69 mm), depth 505 m, MOUFPE-18449 ; paratype: Abracos 2, station 53A, Rocas Atoll (3° 48' 59'' S; 33°59' 16'' W), 2 May 2017, 1 ovigerous female (cl 44.75 mm), depth 65 m, MOUFPE-18736.

Diagnosis (type series): body moderately firm ( Fig. 1 ). Rostrum slightly directed upward dorsally, apex sharp, reaching frontal margin; inferior margin slightly concave or straight ( Fig. 1 , 2A ). Carapace dorsal margin sharply carinate anteriorly to almost middle length ( Fig. 2B ); carapace rounded posteriorly; branchial and suprabranchial carinae weakly developed; deep branchiostegal sinus; small branchiostegal spine, overreaching anterolateral margin ( Fig. 2A ). First pereopod fingers shorter than palm; carpus with small distal spine; merus with 3–6 spines on ventral margin; ischium unarmed; basis with distal spine ( Fig. 3B ). Second pereopod with fingers as long as palm; carpus with small distal spine; merus with 10–14 spines on ventral margin; ischium unarmed and basis with distal spine ( Fig. 3D ). All abdominal somites without posterodorsal tooth ( Fig. 1 , 2C–G ). First abdominal somite dorsally carinate, except the anterior third ( Fig. 2C ); second to fifth abdominal somites dorsally carinate ( Fig. 2D–F ); sixth abdominal somite dorsally carinate, except posterior third ( Fig. 2G ). Telson as long as sixth abdominal somite, shallowly grooved dorsally ( Fig. 2H ); posterior margin slightly concave, distal spines missing, except for one stout outer spine and a pair of small median spines ( Fig. 2I ).

Description: holotype, ovigerous female, cl 42.69 mm: body strongly compressed laterally; integument moderately firm ( Fig. 1 ). Rostrum short, slightly directed dorsally, sharp apex, reaching frontal margin; inferior margin concave ( Fig. 1 , 2A ). Carapace dorsal margin sharply carinate anteriorly to almost its middle length ( Fig. 2B ); frontal margin slightly convex; branchial and suprabranchial carinae weakly developed; deep branchiostegal sinus; small branchiostegal spine, overreaching anterolateral margin ( Fig.1 , 2A ). Cornea darkly pigmented, wider than eyestalk ( Fig. 1 ).

Antennular peduncle moderately stout ( Fig. 1 ); stylocerite strongly compressed laterally with acute apex reaching first segment distal margin ( Fig. 1 ); third segment with small disto-lateral spine. Antennal peduncle basicerite with strong ventrolateral distal tooth; scaphocerite reaching the distal third of maxilliped propod-dactyl ( Fig. 1 ). Antennal scale overreaching thickened aesthetasc-bearing portion of outer antennular flagellum, 0.5 times as long as carapace, 5 times longer than wide, lateral margin evenly convex ( Fig. 2J ).

Third maxilliped with long and slender exopod; palm-dactyl as long as ischio-merus ( Fig. 1 , 3A ).

First pereopod reaching the basal third of second pereopod palm; fingers curved distally, crossing, cutting edges finely pectinate. Palm 6 times longer than wide, with a row of 26 small spines on mesial face adjacent to flexor margin; merus with 3 spines on ventral margin; ischium unarmed; basis with ventro-distal spine; exopod reaching merus midlength ( Fig. 1 , 3B ). Chela bearing row of more than 8 spinules on mesial face ventrally, and more than 10 spinules extending from base of dactylus to proximal part of fixed finger ( Fig. 3C ).

Second pereopod fingers as longer as palm, cutting edges finely pectinate; palm 10 times longer than wide; without spines; merus with 10 spines on ventral margin; ischium unarmed; basis with distal spine; exopod reaching basal third of merus ( Fig. 1 , 3D ).

Posterior three pairs of pereopods typical of genus. Third pereopod very slender, reaching distal third of second pereopod merus; exopod reaching merus midlength ( Fig. 1 , 3E ). Fourth pereopod the shortest one, reaching proximal third of third pereopod merus ( Fig. 1 , 3F ). Fifth pereopod reaching proximal third of third pereopod carpus ( Fig. 1 , 3G ).

All abdominal somites without posterodorsal tooth, dorsally carinate ( Fig. 2E–H ). First abdominal somite dorsally carinate, except anterior third ( Fig. 2C ). Sixth abdominal somite dorsally carinate, except posterior third ( Fig.2G ). Sixth abdominal somite slightly longer than fifth, lateral ridge clearly discernible, acute; posterodorsal margin slightly convex ( Fig. 1 , 3G ).

Telson as long as sixth abdominal somite, shallowly grooved dorsally; slightly concave posterior margin, distal spines missing, except for one stout outer spine and a pair of small median spines ( Fig. 2H, I ). Branchial formula, pleopods, uropods and mouthparts typical of genus.

Type locality: Fernando de Noronha Archipelago ( Brazil).

Distribution: Fernando de Noronha Archipelago and Rocas Atoll ( Brazil).

Remarks: Hayashi (1999, 2004, 2006a, 2006b) recognized three informal species groups in Pasiphaea , but the classification does not cover all species in the genus. The present new species is not referred to any of the three species groups proposed by Hayashi, as outlined below: in the Pasiphaea cristata group ( Hayashi, 2004) the merus of the first pereopod is usually unarmed (or exceptionally bears 1–2 spines) while in Pasiphaea antea n. sp. it bears 3–6 spines. In the P. alcocki group ( Hayashi, 2006a) the posterior margin of telson is always deeply concave but it is slightly concave in P. antea n. sp. In the Pasiphaea sivado group ( Hayashi, 2006b) the carapace is usually not carinate dorsally, the abdominal somites 1–5 are not carinate dorsally and the 6th somite possesses a posterodorsal tooth, while in P. antea n. sp. the carapace and abdominal somites 1–5 are carinate dorsally, and the posterodorsal tooth is absent in the 6th abdominal somite.

As pointed out by Komai et al. (2012), 19 species are not assigned to any of these groups. Pasiphaea antea n. sp. is distinct from all of them, but appears closest to Pasiphaea dorsolineatus Komai & Chan, 2012 . Both species are characterized by the dorsally carinate, but unarmed first to sixth pleomeres and the the possession of a deep branchiostegal sinus on the carapace. Pasiphaea antea n. sp. is distinguished from P. dorsolineatus by several characters. The shape of the rostrum: inferior margin slightly concave and apex reaching frontal margin in Pasiphaea antea n. sp. vs. inferior margin slightly convex and apex not reaching frontal process of carapace in P.

dorsolineatus ; the number of spines on the merus of the first pereopod is 3–6 in Pasiphaea antea n. sp. vs. 1–2 in P. dorsolineatus ; the number of spines on the merus of the second pereopod is 10–14 in Pasiphaea antea n. sp. vs. 7 in P. dorsolineatus ; the carapace branchial and suprabranchial carinae are present in Pasiphaea antea n. sp. vs. only the branchial carina is present in P. dorsolineatus . Carinaton of the dorsal midline of the carapace also seems to be different between the two.

Pasiphaea antea n. sp. seems also to be close to Pasiphaea westindica Tchesunov, 1984 , described from the Caribbean Sea, and to Pasiphaea levicarinata Hanamura, 1994 , from the northwestern Australia. The three species present carinate abdominal somites 2–6 and slightly concave posterior margin of the telson.

The new species described herein differs from P. westindica by the carapace dorsal margin sharply carinate anteriorly in P. antea n. sp. vs. weakly sinuous in P. westindica ; the number of spines on the merus of the first pereopod, 3–6 in P. antea n. sp. vs. 3 in P. westindica and the number of spines on the merus of the second pereopod, 10–14 in P. antea n. sp. vs. 7 or 8 in P. westindica .

Pasiphaea antea n. sp. is easily distinguished from P. levicarinata by the: rostrum always reaching frontal margin vs. not reaching in P. levicarinata ; the number of spines on the merus of the first pereopod, 3–6 in P. antea n. sp. vs. 5–15 in P. levicarinata and by the number of spines on the merus of the second pereopod, 10–14 in P. antea n. sp. vs. 19–30 in P. levicarinata .

Etymology: Specific epithet corresponds to the name of the research vessel, "Antea", used for collecting the new species along the northwestern Brazilian coast.

Figures

FIGURE 1. Pasiphaea antea n. sp., holotype (cl: 42.69 mm), MOUFPE:18449. Lateral view.Scale:0.25 cm.

FIGURE 2. Pasiphaea antea n. sp., holotype (cl: 42.69 mm), MOUFPE: 18449. A. Left side of carapace, lateral view; B. Carapace and eyes, dorsal view; C. First abdominal somite, dorsal view; D. Second abdominal somite, dorsal view; E. Third abdominal somite, dorsal view; F. Fourth and fifth abdominal somite, dorsal view; G. Sixth abdominal somite, dorsal view; H. Telson,dorsal view; I. Posterior margin of telson, dorsal view; J. Left atennal scale,dorsal view (setae omitted).Scale:0.25cm.

FIGURE 3. Pasiphaea antea n. sp., holotype (cl: 42.69 mm), MOUFPE: 18449. Left thoracic appendages. A. Third maxilliped, lateral view; B. First pereopod, lateral view; C. Same, palm, mesial view; D. Second pereopod, lateral view; E. Third pereopod, lateral view; F. Fourth pereopod,lateral view; G.Fifth pereopod, lateral view.Scale: 0.25 cm.