Pseudoleptochelia bulbus, Bamber, Roger N., 2006

Bamber, Roger N., 2006, Shallow water tanaidaceans (Crustacea: Peracarida: Tanaidacea) from New Caledonia and the Loyalty Islands, Zootaxa 1108, pp. 1-21 : 16-20

Pseudoleptochelia bulbus sp. nov.

Figs. 7–9

Material: 1 brooding female, holotype ( MNHN.Ta899), 1 male, allotype ( MNHN.Ta900), on Halimeda, Lagon, Ilot Maitre , New Caledonia, 22º19.41’S 166º20.89’E, 20 m depth, 9/ 11/95 (“Station 99”); coll. Ichiro Takeuchi. 1 female, 1 male, paratypes ( MNHN.Ta901), 1 female, dissected, sample LF3 ‘83’, Baie de Santal, Loyalty Islands, 20º07.27’S 167º07.34’E, 12 m depth on red algae.

Description of female: body ( Figure 7 A) 6.2 times as long as wide, holotype 3.13 mm long. Cephalothorax subrectangular, 1.2 times as long as wide, longer than pereonites 1 and 2 together, with slight rounded rostrum, triangular eye­lobes conspicuous, eyes present and black. Six free pereonites; pereonite 1 shortest, pereonite 4 1.5 times as long as pereonite 3, other pereonites subequal, (all pereonites respectively 2.83, 1.55, 1.6, 1.0, 1.33 and 1.89 times as wide as long). Pleon of five free subequal pleonites bearing pleopods; each pleonite about six times as wide as long. Pleotelson semicircular, longer than last two pleonites together, more than twice as wide as long, with one medial seta on each side, and two simple and two fine distal setae.

Antennule ( Figure 7 B) of four articles, proximal article 2.7 times as long as wide, 1.2 times as long as distal two articles together; second article half as wide as long, single distal and inner setae; third article four to five times as long as wide and as long as second article, with three distal setae and one aesthetasc; fourth article minute with three distal setae.

Antenna ( Figure 7 C) of six articles, proximal article as long as wide with dorsodistal seta; second and third articles as long as wide, second with single dorsal and ventral distal spines, third with dorsodistal spine; fourth article longest, as long as second and third articles together and 5 times as long as wide with three distal setae; fifth article half as long as fourth; sixth article minute.

Mouthparts. Labrum ( Figure 7 D) distinct, rounded, setose. Left mandible ( Figure 7 F) with crenulate lacinia mobilis, crenulation on pars incisiva, pars molaris stout, blunt; right mandible ( Figure 7 E) similar but without lacinia mobilis. Maxilliped ( Figure 7 G) palp first article naked, second article with one outer, three distal but no inner setae, mesiodistal seta exceeding distal margin of third palp article; third and fourth articles with filtering rows of ten and six setae respectively, fourth article with outer seta; basis with five setae, innermost shortest, second seta reaching distal margin of second palp article, three outer longest setae extending to half length of third palp article; each endite distally with single plumose outer seta, small inner seta and five spatulate spines, and finely setose outer ventral face. Labium ( Figure 7 I) wide, distally finely setose, without palp. Maxillule ( Figure 7 H) with nine distal spines and setose outer margin; palp distinct, with two distal setae. Maxilla and epignath not seen.

Cheliped ( Figure 8 A) stout, basis 1.8 times as long as wide; merus triangular with one ventral and two distal setae; carpus twice as long as wide, with three longer ventrodistal setae and sparse, shorter setae along dorsal margin; propodus nearly twice as long as wide, with distal row of four short spines adjacent to implantation of dactylus; fixed finger short with three ventral and three inner setae, cutting edge crenulate, terminal spine subdistal; dactylus simple with proximal seta as long as dactylus.

Pereopod 1 ( Figure 8 B) longer than other pereopods, coxa with seta; basis slender, nearly 4 times as long as wide, naked; ischium half as long as wide with one seta; merus and carpus subequal; carpus with two distal setae; propodus 1.7 times as long as carpus, with fine setae along dorsal margin, three dorsodistal setae, longer ventrodistal seta; dactylus slender, naked, extending into shorter slender unguis, the two together as long as propodus.

Pereopod 2 ( Figure 8 C) more compact than pereopod 1, basis with proximodorsal seta; ischium with single ventral seta; merus slightly longer than carpus, merus with dorsodistal seta and ventrodistal spine, carpus with single dorsodistal seta and paired ventrodistal tooth­like spines; propodus twice as long as carpus with two dorsodistal setae and single ventrodistal tooth­like (“molar”) spine; dactylus and short unguis shorter than propodus.

Pereopod 3 similar to pereopod 2, but with two setae on ischium.

Pereopod 4 ( Figure 8 D) basis stout, 1.4 times as long as wide; ischium short with two ventral setae; merus and carpus subequal; merus naked; carpus with single dorsodistal seta, paired distal molariform spines and fine comb­rows of setules; propodus with single ventrodistal and mesiodistal molariform spines, two dorsodistal setae nearly as long as dactylus plus unguis, distal crenulate spine; dactylus and unguis fused into claw, curved.

Pereopod 5 as pereopod 4.

Pereopod 6 ( Figure 8 E) similar to pereopod 4, articles stouter, merus with ventrodistal molariform spine, carpus without distal seta, propodus with distal crown of two denticulate and three simple setae, dactylus with ventrodistal apophysis.

Pleopods ( Figure 7 J) all alike, basis naked; endopod with single inner plumose seta.

Uropod ( Figure 8 F) biramous, basis with four inner distal setae; exopod of two fused segments, exceeding second endopod segment, outer distal seta longer than inner distal seta; endopod of seven segments, proximal pair compact, remainder increasing from twice to six times as long as wide.

Description of male: Smaller than female (allotype length 2.4 mm), body ( Figure 9 A) more compact, cephalon longer than pereonites 1 to 3, with large eye­lobes bearing large black eyes; pereonites subequal, pereonite 5 longest. Five free pleonites, subequal in length, pleotelson 1.5 times as long as pleonite 5.

Antennule ( Figure 9 B) first peduncle article 3.75 times as long as wide, naked; second article 0.6 times as long as first with ventrodistal rounded apophysis, probably fusion of third article; flagellum of 11 segments, proximal article with two rows of 22 and 20 aesthetascs, each remaining article bearing proximal row of aesthetascs, respectively 18, 18, 18, 16, 12, 9, 8, 8, 6 and 1 per article.

Antenna ( Figure 9 C) similar to but more slender than that of female, fifth article 1.2 times as long as fourth article.

Mouthparts atrophied.

Cheliped ( Figure 9 D) of subchelate type; merus with four ventrodistal setae, carpus with irregular ventral setae; propodus fixed finger a small, pointed apophysis with terminal spine, two ventral and single dorsal setae, and row of 12 short and two longer inner setae subdistally near base of dactylus; dactylus slender, 0.9 times as long as propodus, with row of fine setae along cutting edge, terminal spine pointed.

Pereopods slender, sparsely setose; pereopod 1 ( Figure 9 E) merus with dorsodistal seta, carpus longer than merus with four distal setae, propodus longer than carpus with ventrodistal seta, dactylus with unguis together shorter than propodus.

Pereopods 2 ( Figure 9 F) and 3 similar to pereopod 1, basis with proximal dorsal seta, dactylus plus unguis proportionately shorter.

Pereopod 4 ( Figure 9 G) more compact than pereopod 1, merus and carpus with distal setae.

Pereopod 5 as pereopod 4.

Pereopod 6 ( Figure 9 H) as pereopod 4 but merus as long as carpus, carpus with distal short spines.

Pleopods more setose than those of female. Uropods similar to those of female.

Etymology: from the Latin bulbus , a swelling (noun in apposition), referring to the distal swelling of antennule peduncle article 2 in the male.

Remarks: Bamber (in press) discussed the increasingly blurred distinctions between the leptocheliid genera Leptochelia and Pseudoleptochelia (also see remarks under Konarus cheiris above). The present species has the pereopod morphology and elongate uropod articles of Pseudoleptochelia , but five distal setae on the maxilliped basis is a characteristic of Leptochelia . The male, with its subchelate cheliped, is only characteristic of one group of the genus Pseudoleptochelia .

Pseudoleptochelia bulbus sp. nov. is distinct within the genus in having five maxilliped basis setae. The morphology of the male cheliped and antennule show similarity to that of the Mediterranean species P. provincialis (Dollfus) , but the cheliped propodus and the proximal antennule articles are distinctly more elongate. The distal swelling on the second peduncle article of the antennule in the present species appears to be unique. P. bulbus is the second Pacific species of this genus after P. filum (Stimpson) , recorded from the Pacific coast of North America, a species with fewer articles in a proportionately longer uropod, and with a better developed cheliped fixed finger, inter alia (male unknown) (e.g. Richardson 1905).

Figures

FIGURE 7. Pseudoleptochelia bulbus sp. nov., female: A, holotype, dorsal; B, antennule; C, antenna; D, labrum, lateral; E, right mandible; F, left mandible; G, maxilliped, palp setae shown on left only, basis setae on right only; H, maxillule; I, labium; J, pleopod (most setae shown only by their bases). Scale line = 1 mm for A, 0.2 mm for B and C, 0.15 mm for D to J.

FIGURE 8. Pseudoleptochelia bulbus sp. nov., female: A, cheliped; B to E, pereopods 1, 2, 4 and 6 respectively; F, uropod. Scale line = 0.2 mm for A, 0.15 mm for B to F.

FIGURE 9. Pseudoleptochelia bulbus sp. nov., male: A, allotype, lateral; B, antennule (aesthetasc length indicated on first flagellar segment, otherwise not shown); C, antenna; D, cheliped, with detail of inner spination of propodus; E to H, pereopods 1, 2, 4 and 6 respectively. Scale line = 1 mm for A, 0.4 mm for B and C, 0.2 mm for D to H.