Pardaliscoides whiteae, Ortiz & Winfield & Ardisson, 2023

Ortiz, M., Winfield, I. & Ardisson, P. L., 2023, AnewbathyalspeciesofPardaliscoides (Amphipoda, Amphilochidea, Pardaliscidae) from off the southwestern Gulf of Mexico, Zootaxa 5264 (2), pp. 284-292 : 285-291

publication ID	https://doi.org/ 10.11646/zootaxa.5264.2.8
publication LSID	lsid:zoobank.org:pub:71D03ABC-F0A9-4C24-8BF9-918E1BC90F82
DOI	https://doi.org/10.5281/zenodo.7836523
persistent identifier	https://treatment.plazi.org/id/2A0787FE-FFC0-FF90-FF52-F97F7CF8B437
treatment provided by	Plazi
scientific name	Pardaliscoides whiteae
status	sp. nov.

Treatment

Pardaliscoides whiteae View in CoL sp. nov.

( Figs 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Type Material. Holotype male 3.4 mm; CNCR36590 , dissected on slides; collected from the type locality on SW Gulf of Mexico. Type locality. Bay of Campeche , SW Gulf of Mexico, cruise site number 57-33 at 20°11’44.87”N, 94°32’ 41.14”W. The material was collected from soft-bottom characterized by mud (silty-clay) sediments of terrigenous origin at 2125 m depth. GoogleMaps

Etymology. This new species is named to honour Kristine White for her valuable contribution to the study of Amphipoda . It is derived from the noun ‘white’ in the genitive case.

Diagnosis. Based on the male holotype (CNCR36590). Head without eyes; rostrum short; pereonites 5–7 subequal in length but much longer than 1–4; pleonites 1–3 successively elongated, 1.3 x longer than pereon, scarce setae; antenna 1 accessory flagellum 10–articulate, primary flagellum 13–articulate; antenna 2 peduncle article 4, 1.2 x longer than 5, flagellum 9–articulate; lower lip distorted, asymmetric; mandibles without molar; maxilliped powerful, palp very long; maxilla 1 palp 2–articulate, 6 distal and 5 subdistal setae; gnathopods similar, simple, carpus as long as basis, convex posterior margin, dactylus curved, subequal in length to propodus; pereopod 3 shorter than 4, ischium not elongate; pereopods 5–7 elongate, slender; pereopod 7 expanded; epimeron 3 with posteroventral corner right angle; uropod 1 and 2 outer rami cylindrical, strongly curved; uropod 3 rami distal half flattened, fleshy-lined, with marginal short robust setae; telson longer than wide, notched 12.5% of length.

Description. Holotype male, 3.4 mm (CNCR36590). Body ( Fig. 2 View FIGURE 2 ) pereonite 1 shorter than head; pereonites 1–4 subequal in length. Antenna 1 ( Fig. 2 View FIGURE 2 ) 2 x length of antenna 2, scarce setae, 0.7 x body length, peduncular article 2, 1.5 x article 1, primary flagellum 13–articulate; accessory flagellum 10–articulate. Antenna 2 ( Fig. 2 View FIGURE 2 ) peduncle article 4, 1.2 x article 5, flagellum 9–articulate. Head ( Fig. 3A View FIGURE 3 ) subequal in length to pereonites 1–2 combined, without eyes; rostrum short, distally pointed; lateral cephalic lobe broadly rounded, ventral margin of head shallowly concave.

Mouthparts ( Fig. 3 View FIGURE 3 ). Maxilliped ( Fig. 3B View FIGURE 3 ) powerful, raptorial; inner plate not reaching base of palp, with two distal robust setae; outer plate surpassing base of palp, with three distal and five medial robust setae; palp article 1 naked, article 2 subequal article 3 in length, inner margin with more than 20 long and short simple setae, article 3 inner margin irregular (almost serrate), distal half with ten long and short setae, article 4 subequal article 1 in length, article 5, 0.7 x length of article 4. Mandibles asymmetric without molar; right mandible ( Fig. 3C View FIGURE 3 ) with three-pointed incisor process, lacinia mobilis absent; accessory setal row with two stout setae, palp 3–articulate, article 2 with 6–8 long setae, article 3 shorter than 2, curved, with four long distal setae; left mandible ( Fig. 3D View FIGURE 3 ) with two big and three shallow cuspid incisors, lacinia mobilis broad, slightly denticulate, accessory setal row with four stout setae. Upper lip ( Fig. 3E View FIGURE 3 ) ventral margin shallowly incised, lobes symmetric. Lower lip ( Fig 3F View FIGURE 3 ) asymmetric. Maxilla 1 ( Fig. 3G View FIGURE 3 ) outer plate with inner margin distally pointed, seven robust setae; inner plate vestigial, devoid of setae; palp 2–articulate, six distal, and five subdistal setae. Maxilla 2 ( Fig. 3H View FIGURE 3 ) longer than wide, outer plate with three distal setae, inner plate with four.

Gnathopod 1 ( Fig. 4A View FIGURE 4 ) slightly smaller than 2, simple; coxa 1 subsquare, not anteriorly produced; basis as long as carpus, with long simple setae on inner margin, short scarce setae on outer; ischium short; bare margins; merus 1.3 x ischium, five simple setae on distal outer margin; carpus posterior margin convex and serrate, with three long serrate setae and two long simple setae, seven simple setae on anterior margin; propodus as long as dactylus, two serrate setae on basal posterior margin, five simple setae distally; dactylus long, slightly curved, naked. Gnathopod 2 ( Fig. 4B View FIGURE 4 ) coxa 2 rounded; basis as long as carpus, distal anterior margin with six long simple setae, distal posterior margin with six short simple setae; ischium shorter than merus, distal posterior margin with three setae; merus with seven posterodistal setae; carpus posterior margin convex, with 25–27 long serrate setae; propodus 0.7 x as long as carpus, tapering distally, posterior margin with nine setae; dactylus curved, 0.8 x as long as propodus; gill cylindrical, half-length of basis.

Pereopod 3 ( Fig. 5A View FIGURE 5 ) coxa subconical forming an incipient posterior lobe, shorter than coxa 4; basis subequal in length to merus and carpus combined; merus 0.8 x carpus; carpus subequal in length to propodus; dactylus curved, subequal in length to propodus, gill cylindrical, 0.3 x basis. Pereopod 4 ( Fig. 5B View FIGURE 5 ) coxa subrectangular, slightly bilobate; basis 0.8 x merus and carpus combined; carpus curved backward, shorter than propodus; dactylus half propodus length, gill cylindrical, 0.3 x length of basis. Pereopod 5 ( Fig. 5C View FIGURE 5 ) coxa bilobate, slightly longer than 4; basis, merus and carpus subequal in length; carpus and propodus slightly curved; propodus 0.8 x carpus; dactylus 0.6 x length of propodus; gill 0.5 x basis. Pereopod 6 ( Fig. 3D View FIGURE 3 ) coxa wider than deep, almost subovate; basis ovoidal, 0.8 x longer than wide; merus 1.2 x longer than basis; merus subequal to propodus in length; dactylus 0.6 x propodus; gill 0.5 x length of basis. Pereopod 7 ( Fig. 5E View FIGURE 5 ) coxa wider than deep, subrectangular, as wide as coxa 6; basis ovoidal, expanded, 1.3 x as long as wide; ischium short; merus 1.4 x as long as carpus; carpus 1.3 x propodus; dactylus 0.7 x as long as propodus.

Epimera 1–3 ( Fig. 6B View FIGURE 6 ) ventral margins with 4–6 simple tiny setae. Urosome ( Fig. 6C View FIGURE 6 ) half-length of pleon; urosomite 2 longest; urosomite 1–2 with a distinct bifid tooth projecting posterodorsally; urosomite 3 with a long posteroventral tooth directed posteriorly. Uropod 1 ( Fig. 6C View FIGURE 6 ) peduncle very long; twice as long as inner ramus; outer ramus strongly curved, with two robust setae on inner margin; inner ramus almost straight, three robust setae on inner margin, one on lateral margin. Uropod 2 ( Fig. 6C View FIGURE 6 ) peduncle 1.7 x as long as inner ramus, outer ramus strongly curved, with two robust setae on inner margin; inner ramus straight, widened along its length, naked. Uropod 3 ( Fig. 6D View FIGURE 6 ) peduncle half-length of outer ramus, rami flattened, distal half of rami with marginal short robust setae, fleshylined. Telson ( Fig. 6A View FIGURE 6 ) twice as long as wide, with a long subcentral seta on each side, cleft extending to 12% of length, with a small lobe at the base of the cleft.

Remarks. Currently, with the new species described in this paper, the genus Pardaliscoides comprises six deep-sea species, inhabiting from 218 m to 10000 m depth. Unfortunately, the description of some of these species is incomplete owing to e.g. the poor condition of the holotype ( P. ecosur ), the incomplete description made ( P. fictotelson ), or the an incomplete set of illustrations provided ( P. longicaudatus , P. tenellus , and P. stebbingi ). Despite the incomplete data, we have been able to determine two groups of species based on the telson: type 1- deeply cleft with lobes tapering distally ( P. ecosur , P. stebbingi , and P. tenellus ); type 2-shallow cleft telson with quadrangular notch ( P. fictotelson and P. whiteae sp. nov.).

Pardaliscoides whiteae sp. nov. differs from the five other Pardaliscoides species in having antenna 1 with a 10-articulate accessory flagellum; maxilliped palp very long; pereopods 5–7 elongate, slender; telson with a short U–shaped cleft and pointed lobes; uropods 1–2 outer ramus curved, peduncle flat, longer than rami; uropod 3 rami flat, fleshy-lined, with marginal distal short robust setae. The new species is morphologically closest to P. fictotelson (California, Eastern Pacific Ocean) based on gnathopods 1–2 with a wide tuft of setae on merus posterior margin, similar telson (type 2), uropod 1 curved outer ramus, and foliaceus rami on uropod 3. However, both Pardaliscoides species can be easily differentiated by the accessory flagellum articles, the peduncle of uropod 1 length, the setae on telson, and the more widely expanded basis of pereopod 7. Major morphological differences between species of Pardaliscoides are shown in the identification key.