Lanceola gruneri, Zeidler, 2009

Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 2000, pp. 1-117 : 53-54

Lanceola gruneri sp. nov.

( Fig. 18)

Material examined. Holotype. Male , 8.5mm ( ZMUC CRU–3919); Tasman Sea , between Sydney, Australia and the North Island of New Zealand [33º30.5’S 165º53’E]; Dana Stn. 3653 VII, 3500 mw, 26 Jan. 1929.

Description of holotype. Male, 8.5 mm. Pereon length almost twice pleon, not inflated; pereonites gradually broader from seventh to second; the first narrows slightly anteriorly, almost overhanging head. Pereonite

2 with dorsal medial ridge extended over pereonite 1, almost reaching head and with anterior depression either side of ridge. Pereonites 3 & 4, and to a lesser extent pereonite 5, with dorsal, medial depression, extended anteriorly, indenting preceding pereonite. Head with short, broad rounded rostrum that is not apparent from dorsal aspect. Eyes small, reniform, without crystalline cones. Antennae 1 (right missing) as long as head and first pereonite combined; callynophore with numerous, well-developed aesthetascts; terminal article linear, rounded, slightly longer than two preceding articles combined. Antennae 2 marginally shorter than A1. Gnathopoda typical of Lanceola , most similar to L. clausi . Gnathopod 1; basis with small anterior bulge, about as long as ischium–propodus combined; dactylus length slightly less than half propodus. Gnathopod 2 similar to G1 but a little longer and more slender. Pereopod 3 similar to, but marginally shorter than, P4; basis length about twice merus; merus with rounded anterodistal corner, slightly projected over carpus and armed with 2–3 fine setae; carpus length 1.3x merus (more or less); propodus length 1.2x carpus; dactylus length about 0.3x propodus. Pereopod 5 slightly shorter than P4; basis length 1.4x merus; merus with rounded posterodistal corner, slightly projected over carpus; armed with three fine setae; carpus subequal in length to merus; propodus slightly longer than carpus, without spoon-shaped formation, but with small shield overlapping dactylus medially; dactylus partly retractile, relatively straight, length about one third of propodus with less than half retractile or inserted in propodus. Pereopods 6 & 7 with retractile, fully hooded dactyls and relatively stout articles. Pereopod 6 slightly shorter than pereon, only slightly longer than P5; basis length 1.4x merus; merus with rounded posterodistal corner, slightly projected over carpus, armed with 2–3 fine setae; carpus subequal in length to merus; propodus length 1.3x carpus, with spoon-shaped formation for curved dactylus. Pereopod 7; length 0.8x P6; basis length slightly more than 1.8x merus; merus with rounded posterodistal corner, slightly projected over carpus, armed with 2–3 fine setae; carpus subequal in length to merus; propodus length 1.5x carpus, with spoon-shaped formation for curved dactylus. Peduncle of U1 does not exceed limit of peduncle of U2. Peduncles of U2 & 3 relatively broad, that of U3 0.7x length. Telson rounded, length about 0.8x (or more) peduncle of U3.

Colour of living specimen not known.

Etymology. This elegant species is named for Dr Hans-Eckhard Gruner, formerly Curator of Crustacea, Zoologisches Museum der Humbolt Universität zu Berlin in recognition of his contribution to the study of hyperiidean amphipods. Dr Gruner was also responsible for sorting the Dana collections to genus level thus making this material readily accessible for study.

Remarks. Although only known from the unique type, the characters distinguishing this species are welldefined and unlike any other congener. In particular, the dorsal ridge of pereonite 2, which extends to almost the head; and the dorsal depression of pereonites 2–4/5, is a character not found in any other species of Lanceola . In the relatively short second antennae it only resembles L. clausi pirloti and the structure of the partly retractile dactylus of pereopod 5 is only approached by L chelifera ( Fig. 16). The gnathopoda and urosome are most similar to L. clausi and L. falsa .

The type has well-developed, delicate gills and the callynophore of the first antennae is furnished with a dense brush of aesthetascts, indicating that this is most likely a sexually mature specimen.

Distribution. Only known from the unique type from the South-West Pacific (Tasman Sea) as detailed above.