Lycaea pachypoda (Claus 1879)
- Dataset
- Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea)
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Amphipoda
- family
- Lycaeidae
- genus
- Lycaea
- species
- Lycaea pachypoda
description
(Figs 12 – 13)
diagnosis
Diagnosis. Body length of females up to 6.0 mm, males up to 7.0 mm. Body of females more globular than other congeners. Head of females relatively small, almost 2 x as deep as long, as long as first 3 pereonites combined. Head of males more rounded than in females, marginally longer. Buccal mass protruded well below head. Callynophore of A 1 of males without antero-distal corner; postero-distal corner small, rounded, barely partly over-lapping following article. G 1 and G 2 almost simple, morphologically similar, G 2 slightly longer than G 1. G 1 basis very broad, width about 0.5 x length, with inflated anterior margin; carpus sub-quadrate with slightly serrated postero-distal corner, extending slightly posterior to propodus; propodus with postero-distal corner produced posteriorly to dactylus; dactylus robust, length about 0.5 x propodus. G 2 similar to G 1 but basis more slender and longer, carpus slightly narrowed distally and postero-distal corner of propodus is smaller. P 3 – 6 with relatively short, stubby dactylus, those of P 3 and P 4 only about 0.2 x propodus. P 3 and P 4 morphologically similar, P 4 marginally longer than P 3; merus slightly inflated anteriorly, length sub-equal to propodus or slightly longer, about 0.5 x basis; carpus sub-equal in length to propodus. P 5 only slightly longer than P 6, about 1.3 – 1.4 x P 4; basis rectangular, length 1.6 x maximum width (marginally less in males); merus marginally inflated anteriorly, slightly shorter than propodus, about 0.5 x length basis; carpus length about 0.8 x propodus. P 6 basis relatively broad, length 1.4 x maximum width, almost as long as basis of P 5; merus broader than for P 5, maximum width about 0.6 x length, sub-equal in length to propodus, marginally longer than 0.4 x basis; carpus slightly inflated, length marginally less than 0.8 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P 7 basis with bulging posterior margin (more proximally in females), length about 1.8 x maximum width, slightly more than 0.8 x basis of P 6; length of remaining articles 0.5 – 0.6 x basis; propodus with antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U 1 and U 2; endopod not fused with peduncle. U 1 peduncle length about 2.0 x exopod; endopod slightly broader than endopod, equal in length. Telson length about 1.4 x width at base, or marginally shorter.
discussion
Remarks. Lycaea pachypoda is readily distinguished from all its congeners by the morphology of G 1 and G 2, which are almost simple. Prior to Vinogradov et al. (1982, 1996) this species was relegated to the monotypic genus Pseudolycaea Claus, 1879. However, apart from G 1 and G 2, it is very similar to other species of Lycaea and the generic distinction cannot be maintained. Like L. pulex, L. pachypoda has been recorded from the salp Salpa maxima and pyrosomes (Chevreux 1892, 1900; Chevreux & Fage 1925; Laval 1980). It has also been recorded from the medusa Liriope tetraphylla (Chamisso & Eysenhardt, 1821) (Harbison et al. 1977).
distribution
Distribution. A relatively uncommon species but widely distributed in the tropical and temperate regions of all the world’s oceans, including the Mediterranean Sea, generally between the Subtropical Convergences. Vinogradov (1962) also records it from the Southern Ocean, off Australia, at about 45 ° S. Most catch records are from nearsurface waters.
materials_examined
Type material. Type material of Pseudolycaea pachypoda could not be found in any major European institution and is considered lost. The type locality is the Mediterranean Sea, near Messina, Italy and the western Indian Ocean, near Zanzibar. Claus’s (1887) illustration of a female readily characterise this distinctive species. Material examined. In NHMD: numerous specimens from the Dana and Thor expeditions and others, too many to list here, from all the World’s Oceans including the Mediterranean Sea. In SAM: S. W. Atlantic: off South Africa [33 ° S 17 ° 19 ’ E & 35 ° 40 ’ S 18 ° 06 ’ E], 2 females (2 lots). In SAMA: S. W. Pacific, Tasman Sea, off central eastern Australia [about 34 ° – 43 ° S], 22 females, 14 males (9 lots), C 5265 – 73 and off eastern Tasmania [42 ° 45 ’ – 44 ° 14 ’ S], 15 females, 9 males (7 lots), C 12570 – 76. In USNM: N. W. Atlantic, Bermuda [31.93 ° N 63.77 ° W], 1 female, extracted from 1153747. N. E. Pacific, off Central America [12 ° 27 ’ N 111 ° 42 ’ W and 14.517 ° N 109.533 ° W], 2 females, 1264034, 1264063.
Name
- Synonyms
- Pseudolycaea pachypoda Claus 1879
- Homonyms
- Lycaea pachypoda (Claus 1879)