Paralanceola wolffi, 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 : 25-29

Paralanceola wolffi sp. nov. ( Figs 8 & 9 )

Material examined (4 males)

Holotype. Male, 5.6 mm ( ZMUC CRU­ 4363); western South Pacific, near the Kermadec Islands [30°08S, 176°50W]; collected by Dana (Stn. 3627 III), 3000 mw, 14 Dec. 1928.

Paratypes. 1. Male, 6.0 mm ( ZMUC CRU­ 4364); eastern South Atlantic, near Gulf of Guinea [0°31S, 11°02W]; collected by Dana (Stn. 4000 IX); 3000 mw, 4 March 1930. 2. Two males, 4.0, 4.6 mm ( ZMUC CRU­ 4365); North Atlantic, Bay of Biscay [46°28N, 8°01W]; collected by Dana (Stn. 4158 XV); 3000 mw, 18 June 1930.

Diagnosis

Males reach lengths of at least 6.0 mm. Head with small rostrum and anterolateral lobe overlapping most of first flagellar article of A1. Eyes absent or very small, composed of up to seven ocelli. Antennae 1 as long as head and first 1.5 pereonites; callynophore conical, as long as peduncle; with two small terminal articles, the terminal one twice as long as the previous one, tipped with one long seta. Antennae 2; length about 0.7x A1; 6­articulate; fourth article twice length third; two small terminal articles with three long setae terminally. Mandibular palp; length third article 1.2–1.3x articles 1 & 2 combined. Maxillae 1; palp with several short fine setae, one robust seta and 4–5 tubercles terminally; outer lobe with five robust setae, one slightly more slender than others. Maxillae 2; inner lobe with three, and outer lobe with four, relatively long, robust, dentate setae. Maxilliped; outer lobes with dentate inner margin; inner lobes, length about one­third outer lobes. Pereopods 3 & 4 slightly shorter than P5 (=0.8x). Pereopod 6 similar in length to P3. Pereopod 7 the longest pereopod; length about 1.2x P6 and slightly longer than P5. Pereopods 5–7 with retractile and hooded dactyls. Uropod 1; peduncle reaching just beyond limit of peduncle of U2. Telson length about 0.7x peduncle of U3.

Description of holotype

Male 5.6 mm. Cuticle with faint hexagonal markings. Pereon slightly inflated mainly because of enlarged pereonites 2–4. Pleon length 0.4x pereon. Head with short, rounded rostrum and relatively acute anterlateral lobes, almost reaching limit of first peduncular article of A1. Eyes absent or not discernable. Antennae 1; first peduncular article one­third longer than second; second article with faint, suture­like impression on surface but no evidence of third peduncular article; callynophore tapering abruptly, as long as peduncle, with medial two­field brush of aesthetascs; setae missing from terminal article. Antennae 2; 6­articulate; gland cone as long as first two articles combined; first two articles of similar length, about 0.6x length third; fourth article twice length third; terminal article slightly shorter than preceding one, with three long setae terminally; articles 2–6 with several long setae dorsally and medially. Mandibular palp; length first article about 0.75x second; second article slightly curved with two long setae mid­way and one distally; length third article slightly more than 1.2x first two combined, with series of denticles ventrally for distal half or slightly more. Maxillae and maxilliped as in diagnosis. Gnathopod 1; basis slightly shorter than carpus and propodus combined; merus densely denticulate on medial surface; propodus length about 0.8x carpus; merus, carpus and propodus armed with bifid, feathered, relatively robust, setae; dactylus thin and straight, length 0.6x propodus, inserted subterminally. Gnathopod 2 slightly longer and more slender than G1; similar to G1 except propodus slightly longer than carpus. Pereopods 3 & 4 similar in length and structure, a little shorter than P5; basis slightly shorter than merus and carpus combined; merus, carpus and propodus subequal in length, armed with series of long and short setae on posterior margin. Pereopods 5–7 with retractile and hooded dactyls. Pereopod 5; basis with sharp anterodistal lobe, overlapping more than half of ischium, length about 1.2x merus and carpus combined; merus length 1.2x carpus; carpus slightly longer than propodus; merus, carpus and propodus with series of long and short setae on anterior margin. Pereopod 6 slightly shorter than P5 but slightly longer than P3 or 4; basis length about 1.3x merus; merus length 1.6x carpus; propodus slightly longer than carpus; carpus and propodus with few setae on anterior margin. Pereopod 7 the longest pereopod, only slightly longer than P5, 1.2x length P6; basis length 1.2x merus; merus length about 1.8x carpus; propodus length 1.5x carpus. Uropod 1; peduncle with finely toothed outer margin; rami with both margins toothed; tips of rami broken but similar in length to peduncle. Uropod 2; rami armed like U1; peduncle extends to limit of peduncle of U1; outer ramus slightly longer than peduncle; inner ramus almost 1.3x length outer. Uropod 3 armed like U2; length outer ramus 1.2x peduncle; length inner ramus almost 1.2x outer. Telson pointed, a little longer than wide, as long as two­thirds peduncle of U3.

Va r i a t i o n

Paratype 1 is just like the holotype. The other two specimens differ only in that they appear to have very small eyes made up of about eight ocelli and, in the smaller specimen, the anterolateral lobe of the head is more rounded and not projected as far forward ( Fig. 9 ) and pereopod 7 is similar in length to pereopod 5.

Etymology

This species is named for Dr Torben Wolff, formerly Curator of Crustacea at the ZMUC and one of the grand old men of marine biology and crustacean systematics.

Remarks

This species is very similar to P. anomala in a number of characters but is readily distinguished from it by the structure of the male second antennae and by the following characters, and from the other new species of Paralanceola described here, as detailed under that species. Compared to P. anomala , in P. wolffi the head has a rostrum and anterolateral lobes; the inner lobes of the maxilliped are relatively much shorter; pereopod 7 is the longest pereopod instead of pereopod 5; pereopod 6 is much shorter than pereopod 7 instead of being similar in length; the peduncle of uropod 1 only reaches to the limit of the peduncle of uropod 2 and the telson is shorter relative to the peduncle of uropod 3.

An unusual character of P. wolffi is the slightly inflated pereon of males, a character usually associated with females of Archaeoscina . In Archaeoscina juvenile females, with slightly inflated pereons, can be distinguished by oostegite buds, in addition to gills, at about 2.0 mm. No evidence of oostegite buds was found in any specimens of P. wolffi , ranging in size from 4.0 to 6.0 mm. Thus, I am reasonably confident that they are all males, and that males of this species are characterized by a slightly inflated pereon. This is supported by the fact that the degree of pereon inflation is the same for all specimens regardless of size. In addition the peduncle of antennae 1 is 2­articulate which is characteristic of males of Archaeoscina . However, it is important to note that, in all specimens, the second article of the peduncle has a faint, suture­like impression but there is no evidence of a third peduncular article.

Both the holotype and paratype 1 appear to be sexually immature, judging by the under­developed aesthetascs on the callynophore of the first antennae. This raises the possibility that sexually mature males may develop the type of second antennae seen in P. anomala . However, this is readily discounted because the type of P. anomala is also sexually immature. Also, in those species of Hyperiidea that have males with second antennae that are whip­like and often folded ( Scina and Platysceloidea), the articles of the second antennae of immature specimens are shortened and thickened, devoid of setae and often partly folded, unlike that seen in P. wolffi .

Paratype 1 was caught at the same station as specimens of Archaeoscina steenstrupi and the holotype of the following species, but in different samples.

Distribution

The type locality is the western South Pacific, near the Kemadec Islands. The paratypes were captured in the South Atlantic, near the Gulf of Guinea and in the North Atlantic, in the Bay of Biscay; all with 3000 m of wire out.

Figures

FIGURE 8. Paralanceola wolffi, sp. nov., western South Pacific, ZMUC CRU­ 4363. Holotype male, 5.6 mm. A, lateral view; B, dorsal view of head. Scale bars = 0.5 mm (A, B), 0.2 mm (A 1 & 2, Us), 0.1 mm (mouthparts).

FIGURE 9. Paralanceola wolffi, sp. nov., western South Pacific, ZMUC CRU­ 4363; holotype male, 5.6 mm (G 1 ­ P 7). North Atlantic, Bay of Biscay, ZMUC Cru­ 4365; paratype male, 4.0 mm (A, A 1). A, lateral view of head. Scale bar = 0.2 mm.