Pardaliscoides whiteae Ortiz & Winfield & Ardisson 2023, sp. nov.
Creators: name: Ortiz, M.
name: Winfield, I.
name: Ardisson, P. L.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Pardaliscidae
Pardaliscoides
Pardaliscoides whiteae

description: Pardaliscoides whiteae sp. nov.
(Figs 2–6)
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.
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) pereonite 1 shorter than head; pereonites 1–4 subequal in length. Antenna 1 (Fig. 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) peduncle article 4, 1.2 x article 5, flagellum 9–articulate. Head (Fig. 3A) 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). Maxilliped (Fig. 3B) 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) 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) with two big and three shallow cuspid incisors, lacinia mobilis broad, slightly denticulate, accessory setal row with four stout setae. Upper lip (Fig. 3E) ventral margin shallowly incised, lobes symmetric. Lower lip (Fig 3F) asymmetric. Maxilla 1 (Fig. 3G) 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) longer than wide, outer plate with three distal setae, inner plate with four.
Gnathopod 1 (Fig. 4A) 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) 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) 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) 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) 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) 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) 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) ventral margins with 4–6 simple tiny setae. Urosome (Fig. 6C) 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) 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) 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) peduncle half-length of outer ramus, rami flattened, distal half of rami with marginal short robust setae, fleshylined. Telson (Fig. 6A) 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.
description: Published as part of Ortiz, M., Winfield, I. & Ardisson, P. L., 2023, AnewbathyalspeciesofPardaliscoides (Amphipoda, Amphilochidea, Pardaliscidae) from off the southwestern Gulf of Mexico, pp. 284-292 in Zootaxa 5264 (2) on pages 285-291, DOI: 10.11646/zootaxa.5264.2.8, http://zenodo.org/record/7836518