Lycaea pachypoda

Lycaea pachypoda (Claus, 1879)

(Figs 12–13)

Pseudolycaea pachypoda Claus, 1879: 187 (41).— Carus 1885: 426.— Bovallius 1887: 34 — Claus 1887: 64–65, pl. 20, figs 12–22.— Chevreux 1892: 33.—Chevreux & Fage 1925: 430–431, fig. 420.— Stephensen 1925: 169–171, 230 (tab.), fig. 64.— Spandl 1927: 215–216, fig. 36.— Pirlot 1929: 138–139.— Pirlot 1939a: 43–44.— Pirlot 1939b: 70.— Evans 1961: 203.— Vinogradov 1962: 24–25.—Hure et al. 1969: 603, 605 (tabs.).— Dick 1970: 68, fig. 12 (part).— Tashiro & Jossi 1972: fig. 8 (map), 20 (list), 33 (tab.).— Harbison et al. 1977: 470.— Shulenberger 1977: 379 (tab.).— Shih & Chen 1995: 183–185, figs 120–121.

Lycaea pachypoda. — Hurley 1969: 33, pl. 19 (map 8).— Laval 1980: 19, 20, 23 (tabs.).— Vinogradov et al. 1982 /1996: 382/472 (key), 388–389/479–480, fig. 209.— Barkhatov & Vinogradov 1988: passim.— Vinogradov 1990: 76, 94 (tab.).— Vinogradov 1991: 261 (tab.).— De Broyer & Jażdżewski 1993: 118 (list).— Lin & Chen 1994: 115, 118 (list).— Lin et al. 1995: 122 (tab.).— Lin et al. 1996: 230 (tab.).— Zeidler 1998: 101–104, figs 58–59.— Barkhatov et al. 1999: 808 (tab.).— Vinogradov 1999: 1146 (tab.), 1194 (incl. key), fig. 4.139.— Lowry 2000: 326 (list).— Escobar-Briones et al. 2002: 367 (list).— Gasca 2003b: 118 (tab.).— Vinogradov et al. 2004: 16, 25 (tab.).— Brusca & Hendrickx 2005: 151 (list).— Gasca 2007: 119 (tab.).— Gasca 2009a: 89 (tab.).— Gasca 2009b: 66 (tab.).— Lavaniegos & Hereu 2009: passim.— LeCroy et al. 2009: 969 (tab.).— Valencia & Giraldo 2009: 268 (tab.), passim.— Zeidler & De Broyer 2009: 65–66.—Gasca et al. 2012: passim.— Valencia et al. 2013: 51 (tab.).— Gasca & Franco-Gordo 2014: 75 (list).— Lavaniegos 2014: passim.—Espinosa- Leal & Lavaniegos 2016: 150 (tab.).

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), C5265–73 and off eastern Tasmania [42°45 ’– 44°14’S], 15 females, 9 males (7 lots), C12570–76. 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.

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 A1 of males without antero-distal corner; postero-distal corner small, rounded, barely partly over-lapping following article. G1 and G2 almost simple, morphologically similar, G2 slightly longer than G1. G1 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. G2 similar to G1 but basis more slender and longer, carpus slightly narrowed distally and postero-distal corner of propodus is smaller. P3–6 with relatively short, stubby dactylus, those of P3 and P4 only about 0.2 x propodus. P3 and P4 morphologically similar, P4 marginally longer than P3; merus slightly inflated anteriorly, length sub-equal to propodus or slightly longer, about 0.5 x basis; carpus sub-equal in length to propodus. P5 only slightly longer than P6, about 1.3–1.4 x P4; 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. P6 basis relatively broad, length 1.4 x maximum width, almost as long as basis of P5; merus broader than for P5, 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. P7 basis with bulging posterior margin (more proximally in females), length about 1.8 x maximum width, slightly more than 0.8 x basis of P6; length of remaining articles 0.5–0.6 x basis; propodus with antero-distal corner produced into rounded lobe; dactylus sharp, hook-like. U1 and U2; endopod not fused with peduncle. U1 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.

Remarks. Lycaea pachypoda is readily distinguished from all its congeners by the morphology of G1 and G2, 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 G1 and G2, 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. 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.