Pseudocheles chacei Kensley, 1983

Cardoso, Irene, 2006, Caridea (Crustacea, Decapoda) collected on the Brazilian (13 / 22 S) continental shelf and slope, Zootaxa 1364, pp. 1-44 : 10-15

Pseudocheles chacei Kensley, 1983

( Figs. 7–10 )

Pseudocheles chacei Kensley, 1983:22 –29.

Material examined: 20º24´10”S, 39º55´35”W, 50m, 1 female (2.5mm), MNRJ 19453.

Diagnosis: Carapace, rostrum upper margin with 5–8 teeth, lower margin with a subapical tooth. Stylocerite with broad base, narrowing abruptly to an acute tip. Scaphocerite with small distal spine, not overreaching blade. Abdominal somite three with a dorsal cap covering part of somite 4. Abdominal somite 5, pleura with strong spine on posterior margin.

Description: Carapace with rostrum short, not reaching end of scaphocerite, upper margin with 5 teeth, lower margin with one subapical tooth; rounded antennal lobe, antennal, hepatic and branchiostegal spines absent ( Fig. 7 A). Stylocerite slender, reaching the distal third of basal antennular article ( Fig. 7 B). Scaphocerite with small distal tooth, not overreaching end of blade ( Fig. 7 C). Mandible, incisor process formed by 10 triangular teeth; molar process formed by strong cuspidate setae in a blunt base; palp with two segments ( Fig. 8 A). Maxilla 1, distal endite with 6 long and 4 short cuspidate setae on inner margin; basal endite rounded, with simple setae on upper margin and short cuspidate setae on lower margin; palp with a projection bearing a simple seta ( Fig. 8 B). Maxilla 2, scaphognathite with densely plumose setae on all margins; endopod one-third of scaphognathite length; endite with three lobes, and several simple setae on inner margin ( Fig. 8 C). Maxilliped 1, exopodal lobe broad, with scattered plumose setae on outer margin; exopod absent; endopod as long as exopodal lobe; endite elongate, with plumose setae on inner margin ( Fig. 8 D). Maxilliped 2 with basis elongate; ischium and merus fused; carpus short, curved; dactylus with 4 cuspidate setae on distal margin; exopod short with plumose setae on distal margin ( Fig. 8 E). Maxilliped 3 with ischium and merus fused; propodus-dactylus fused, with serrulate setae on inner margin; elongate exopod with plumose articulated setae on distal and outer margin ( Fig. 8 F). Pereopod 1 stronger and shorter than second; carpus short; broadened propodus; dactylar tip crossing over propodal tip ( Fig. 9 A). Pereopod 2 with elongate ischiomerus; short carpus; dactylar tip overreaching propodal tip ( Fig. 9 B). Pereopod 3, the longest one; ischium with two cuspidate setae; merus with 4 cuspidate setae; carpus short, with one cuspidate seta; propodus broadened with 4 cuspidate setae, the distal one as long as dactylus, seeming to form a chela ( Fig. 9 C). Pereopod 4, ischium with one cuspidate seta; merus with 4 cuspidate setae; carpus short, with one cuspidate seta; propodus broadened, with one distal cuspidate seta as long as dactylus, forming a chela ( Fig. 9 D). Pereopod 5, basis with 2 cuspidate setae; ischium with 2 cuspidate setae; carpus short with one cuspidate seta; propodus elongate with one distal cuspidate seta long as dactylus, forming a chela ( Fig. 9 E). Female endopod of pleopod 1 leaf like with scattered plumose setae on distal margin, and hook setae on tip ( Fig. 10 A). Female endopod of pleopod 2, appendix interna onethird of endopod length, with hook setae on almost all length ( Fig. 10 B). Telson with 3 pairs of dorsolateral cuspidate setae, the distal one small; 3 pairs of distal cuspidate setae, the outer pair strongest ( Fig. 10 C). Endopod of uropod without diaresis; lateral margin not ending in sharp triangular projection; without a posterolateral tooth ( Fig. 10 C).

Distribution: Western Atlantic: Florida (Looe Key), Caribbean Sea ( Belize), Brazil (Espírito Santo).

Remarks: The monotypic genus Pseudocheles was described by Chace & Brown (1978) based on Australian material (P. e n i g m a). Kensley (1983) described a second species, P. chacei based on material from Florida and Belize. The present material is the first record of this genus in the Southwestern Atlantic. The two described species differ in the antennal spine that is minute in P. chacei and well developed in P. e n i g m a; the pleura of abdominal somite 5 that has a strong spine on P. chacei , which is absent in P. e n i g m a; and the exopod of maxilliped 1 is proportionally broader in the Australian material.

The material herein examined fits well with the three features cited above as diagnostic for P. chacei , and with others features cited by Kensley (1983), as shape and setae pattern of mouth parts; pereopods 4 and 5 and telson. The differences noted were: the number of dorsal teeth on rostrum (5 in present material and at least 6 in Kensley´s (1983) description); and the setae pattern of pereopod 3 (with 2 cuspidate setae on ischium, 4 on merus and one on carpus in the present material; and one cuspidate seta on ischium, 3 on merus and one on carpus in Kensley´s (1983) material).

Figures

FIGURE 7. Pseudocheles chacei Kensley, 1983, female, 2.5 mm, MNRJ 19453; A. lateral view; B. right antennule, dorsal view; C. right antenna, dorsal view (st — stylocerite).

FIGURE 8. Pseudocheles chacei Kensley, 1983, female, 2.5 mm, MNRJ 19453; A. left mandible; B. left maxilla 1; C. left maxilla 2; D. left maxilliped 1; E. left maxilliped 2; F. left maxilliped 3.

FIGURE 9. Pseudocheles chacei Kensley, 1983, female, 2.5 mm, MNRJ 19453; A. right pereopod 1, lateral view; B. right pereopod 2, lateral view; C. right pereopod 3, lateral view; D. right pereopod 4, lateral view; E. right pereopod 5, lateral view.

FIGURE 10. Pseudocheles chacei Kensley, 1983, female, 2.5 mm, MNRJ 19453; A. endopod of right first pleopod, lateral view; B. appendix interna, endopod of right second pleopod; C. telson and uropods, dorsal view.