Lycaea lilia Volkov, 1982

Zeidler, Wolfgang, 2021, Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 5081 (1), pp. 1-59 : 18-21

Lycaea lilia Volkov in Vinogradov et al., 1982

( Figs 6–7 )

Lycaea lilia Volkov in Vinogradov et al. 1982: 382 (key), 389–390, fig. 210.—Vinogradov et al. 1996: 472 (key), 480–482, fig. 210.— Lavaniegos & Hereu 2009: 152 (tab.).— Gasca et al. 2010: 934, 938.—Gasca et al. 2012: passim.—Gasca & Franco- Gordo 2014: 75 (list).— Espinosa-Leal et al. 2021a: passim.

Type material. The holotype female (9.0 mm) and some paratypes are held by the Pacific Ocean Scientific Research Institution of Fisheries and Oceanography ( TINTRO). The type locality is the S.E. Pacific [08°S 90°W & 13°S 86°W], 0–100 m.

Material examined. In NHMD: S. Pacific: near Samoa, Dana stns 3558 ii (228124), 3584 vi (228126), 3584 vii (228129), 3588 iii (228130), 3 females, 2 males. China Sea: N. of Luzon, Dana stn. 3729 iii (228131), 1 female. S.E. Indian Ocean: S. of Sumatra, Dana stn. 3856 iv (228133), 2 females. S.W. Indian Ocean: N. of Madagascar, Dana stn. 3931 (228135), 1 female. In USNM: N.E. Pacific: 2 females, 3 males (1242788), “ Colombia , Port Utria, Chaco ”, R/ V Velero III, surface, 15 February 1934 .

Diagnosis. Body length up to about 9.0 mm. Head of females relatively large, rounded, much deeper than long (about 1.5 x), as long as first 3–4 pereonites combined. Head of males almost as long as first 3 pereonites combined, usually with small, anterior knob. Buccal mass protruded well below head. Pereonite 2 of females sometimes with slight dorsal hump. Callynophore of A1 of males without antero-distal corner; postero-distal corner small, rounded, separated from following article by small notch. G1 and G2 sub-chelate, G2 slightly longer than G1. G1 basis slightly shorter than for G2; carpus rectangular with small, rounded postero-distal tooth, reaching just past base of dactylus; propodus with small postero-distal corner produced very slightly over dactylus; carpus and propodus with smooth margins; dactylus very short, stubby, length less than 0.3 x propodus. G2 carpus similar to G1 but distal margin only extends to about the middle of the propodus; propodus of males with few small serrations distally on posterior margin, otherwise similar to G1. P3–6 with very short, stubby dactylus, those of P3 and P4 about 0.2 x as long as propodus, or slightly less. P3 and P4 morphologically similar, P4 slightly longer than P3; merus marginally inflated anteriorly, slightly shorter than propodus, about 0.4–0.5 x basis; carpus length about 0.7 x propodus. P5 length about 1.4 x P4 and about 1.3 x P 6 in both sexes; basis rectangular, length about 2 x maximum width; merus marginally inflated, slightly longer than propodus, about 0.6 x basis; carpus length about 0.7 x propodus. P6 basis oval-shaped, slightly wider distally in males, length about 2 x maximum width, slightly shorter than basis of P5; merus distinctly inflated, maximum width slightly more than 0.6 x length, sub-equal in length to propodus, about 0.5 x basis; carpus also slightly inflated, length almost 0.7 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P7 basis with bulging posterior margin, wider in females, length about 1.5 x maximum width, in males length about 1.7 x maximum width, about 0.7 x basis of P6; remaining articles together relatively long, almost 0.7 x basis in males and almost as long as basis in females; propodus with antero-distal corner produced into small, rounded lobe; dactylus sharp, hook-like. U1 and U2; endopod not fused with peduncle. U1; peduncle relatively short, about 2.5 x length of exopod or only slightly longer; rami relatively slender, equal in length. Telson length about equal to width at base, relatively shorter and more rounded than for other species.

Remarks. Lycaea lilia is readily distinguished from all its congeners, except L. nasuta and L. osbornae sp. nov. by the morphology of G 2 in that the carpus is relatively narrow so that the propodus extends well beyond the postero-distal corner of the carpus. It also shares two other distinctive characters with L. nasuta : the morphology of the head of males is similar and, in some females, the second pereonite has a small dorsal hump. Clearly the two species are closely related but L. lilia is readily distinguished by the morphology of U2 (peduncle and endopod not fused) and the morphology of G1 and G 2 in that the postero-distal corner of the carpus is relatively rounded and does not end in a distinct tooth. It is distinguished from L. osbornae sp. nov. as detailed under that species.

The male of Lycaea lilia has not been illustrated previously in the literature and is unusual in that the head is produced into a small, rounded knob, anteriorly, similar to males of L. nasuta . Unfortunately, of the four males at hand, two are immature and the other two are recent moults so it is impossible to adequately describe the antennae.

A salp associate has not been recorded for this species.

Distribution. A relatively rare species known only from the tropical E. Pacific, the tropical S.E. and S.W. Indian Ocean and the China Sea as detailed above, and from off central Mexico ( Gasca et al. 2010). It seems to prefer shallow waters with records from hauls of 100–0 m and with 50–600 mw.

Figures

FIGURE 6. Lycaea lilia Volkov, 1982. Female, 6.3 mm, USNM 1242788. Scale bars = 0.5 mm (habitus); 0.2 mm (remainder).

FIGURE 7. Lycaea lilia Volkov, 1982. Male, 8.5 mm (recently moulted), USNM 1242788. A2 from male 7.8 mm, NHMD- 228129. Scale bars = 0.2 mm (A1); 0.5 mm (remainder).