Paralanceola oleseni, Zeidler, Wolfgang, 2006

Zeidler, Wolfgang, 2006, A review of the hyperiidean amphipod superfamily Archaeoscinoidea Vinogradov, Volkov & Semenova, 1982 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 1125, pp. 1-37 : 29-33

Paralanceola oleseni sp. nov. ( Figs 10 & 11 )

Diagnosis

Males mature at 7.3 mm. Head without rostrum, slightly concave mid­dorsally; slightly projected forward into rounded lobe ventro­laterally. Eyes absent. Antennae 1 as long as head and first three pereonites; callynophore conical, length 2.4x peduncle; with three small terminal articles, all of similar length. Antennae 2; length 0.5x A1; 7­articulate; fourth article 7.2x length third; with progressively shorter, small terminal articles and four long setae terminally. Mandibular palp; length third article 1.2x articles 1 & 2 combined.

Maxillae 1; palp with four short, robust setae; outer lobe with four robust setae. Maxillae 2; inner lobe with three, and outer lobe with four, robust setae. Maxilliped; outer lobes with smooth inner margin; inner lobes, length about one­quarter outer lobes. Pereopods 3 & 4 slightly shorter than P5 (0.9x). Pereopod 6 similar in length to P4. Pereopod 7 slightly shorter than P6. Pereopods 5–7 with partly retractile dactyls, not hooded. Uropod 1; peduncle barely reaching beyond limit of peduncle of U2. Telson length about 0.6x peduncle of U3.

Description of holotype

Male 7.3 mm. Cuticle with distinct hexagonal markings. Pereon not inflated. Pereonite 7 with distinct genital papillae medially, near base of P7. Pleon length about 0.6x pereon. Head slightly concave mid­dorsally, extended forward anterolaterally into short rounded lobe almost reaching to limit of first peduncular article of A1. Eyes absent or not discernable. Antennae 1; first peduncular article slightly longer than second; second article with sharp distal lobe, medially, overlapping callynophore; callynophore relatively long, tapering gradually, with two­field brush of aesthetascs medially. Antennae 2; 7­articulate; gland cone almost as long as first two articles combined; first two articles of similar length, about 0.6x length third; fourth article 1.3x length third; terminal article with one long and three shorter, slender setae; articles 2–7 with several long setae dorsally and medially. Mandibular palp; length first article about 0.75x second; second article curved with three long setae mid­way and an extremely long one distally; length third article 1.2x first two combined with series of denticles ventrally for distal one­third. Maxillae and maxilliped as in diagnosis. Gnathopod 1; basis slightly shorter than carpus and propodus combined; merus densely denticulate on medial surface; propodus length slightly more than 0.7x carpus; merus, carpus and propodus armed with bifid, feathered, relatively robust setae on posterior margin; anterior margin of carpus and propodus armed with more slender and longer setae; dactylus thin and straight, length 0.5x propodus, inserted subterminally. Gnathopod 2 slightly longer and more slender than G1; similar to G1 except propodus only slightly shorter than carpus, and carpus and propodus not armed with long setae on anterior margin. Pereopods 3 & 4 similar in length and structure, a little shorter than P5; basis slightly shorter than merus and carpus combined; merus and carpus subequal in length; propodus length about 0.8x merus. Pereopods 5–7 with partly retractile dactyls, not hooded. Pereopod 5 the longest pereopod; basis with sharp anterodistal lobe, overlapping most of ischium, length 1.2x merus and carpus combined; merus length 1.3x carpus; carpus length 1.3x propodus; dactylus relatively straight except for proximal onefifth which is retracted into base of propodus, length 0.25x propodus. Pereopod 6 slightly shorter than P5, equal in length to P4; basis length about 1.5x merus; merus length 1.7x carpus equal in length to propodus; dactylus as for P5. Pereopod 7 slightly shorter than P6; basis length 1.5x merus; merus length 1.6x carpus; propodus length 1.2x carpus; dactylus as for P5 but relatively shorter. Uropod 1; peduncle and rami with finely toothed margins; outer ramus slightly shorter than inner, length about 0.6x peduncle. Uropod 2; rami armed like U1; peduncle extends to limit of peduncle of U1; inner ramus about as long as peduncle, almost 1.3x length outer. Uropod 3 armed like U2; inner ramus as long as peduncle, about 1.2x length outer. Telson pointed with almost parallel margins for proximal half, a little longer than wide, 0.6x length peduncle of U3.

Etymology

This species is named for Dr J?rgen Olesen, currently Curator of Crustacea at the ZMUC, in recognition of his invaluable assistance with my studies of hyperiideans.

Remarks

This species is readily distinguished from P. anomala and P. wolffi by the non­hooded and only partly retractile dactyls of pereopods 5–7. In addition it is distinguished from P. anomala by the relatively longer first antennae; the relatively longer callynophore of the first antennae; the morphology of the second antennae; the relatively shorter peduncle of the first uropod and the relatively shorter telson. From P. wolffi it is also distinguished by the head shape; the relatively longer 6­articulate first antennae; the relatively longer callynophore of the first antennae; the sharp process on the second peduncular article of the first antennae; the 7­articulate second antennae; the relatively shorter setae of the maxillae and the second maxillae have setae with only 1–2 denticles; the smooth inner margin of the outer lobes of the maxillipeds; the longer setae on the anterior margin of the carpus and propodus of the first gnathopods and the fifth pereopods are the longest.

In addition to the above, the type male of P. oleseni has distinct genital papillae near the base of the seventh pereopods, a character not found in any other male specimens of Archaeoscinidae examined. Perhaps this character only becomes evident in mature specimens, and the other specimens at hand are immature or, as in the case of Archaeoscina , too small. The type seems to be sexually mature, judging by the welldeveloped aesthetascs on the callynophore of the second antennae and the well­developed genital papillae.

The unique type was captured at the same station as specimens of Archaeoscina steenstrupi and paratype 1 of P. wolffi , but in different samples.

Distribution

Known only from the type locality, the tropical South Atlantic, near the Gulf of Guinea [0°31S, 11°02W], in a sample with 3000 m of wire out.

Figures

FIGURE 10. Paralanceola oleseni, sp. nov., eastern South Atlantic, ZMUC CRU­ 4366. Holotype male, 7.3 mm. A, lateral view; B, medial view of A 1; C, ventral view of head; D, dorsal view of head. Scale bars = 1.0 mm (A­D), 0.2 mm (A 1 & 2, Us), 0.1 mm (mouthparts).

FIGURE 11. Paralanceola oleseni, sp. nov., eastern South Atlantic, ZMUC CRU­ 4366. Holotype male, 7.3 mm. Scale bar = 0.2 mm.