Lycaea serrata Claus, 1879

Zeidler, Wolfgang, 2021, Review of the hyperiidean amphipod family Lycaeidae Claus, 1879 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 5081 (1), pp. 1-59 : 39-42

Lycaea serrata Claus, 1879

( Figs 18–19 )

Lycaea serrata Claus, 1879: 185–186 (39–40).— Bovallius 1887: 32.— Claus 1887: 63, pl. 18, figs 15–20.— Stephensen 1925: 168, 230 (tab.).— Shoemaker 1945 b: 243, figs 38–39.— Dick 1970: 67–68, fig. 12 (part).— Harbison & Madin 1976: 167, figs 3B, 4A-B.— Harbison et al. 1977: 470.— Tranter 1977: 649 (tab.), 651.— Vinogradov et al. 1982 /1996: 382/472 (key), 385–388/477–478, fig. 208.— Barkhatov & Vinogradov 1988: 168 (tab.).— Vinogradov 1990: 75, 94 (tab.).— Vinogradov 1991: 261 (tab.).— Vinogradov 1993: 45 (tab.).— Barkhatov et al. 1999: 808 (tab.).— Vinogradov 1999: 1147 (tab.), 1194 (key), 1195, fig. 4.141.— Escobar-Briones et al. 2002: 367 (list).— Gates et al. 2003: 322.— Brusca & Hendrickx 2005: 152 (list).— Zelickman 2005: xvii (list), fig. 40a-c (pp. 250–255).— Garcia-Madrigal 2007: 156, 192 (list).— Gasca 2007: 119 (tab.).— Gasca 2009a: 89 (tab.).— Lavaniegos & Hereu 2009: passim.—Gasca et al. 2012: passim.— Valencia & Giraldo 2012: 1492 (tab.).— Valencia et al. 2013: 51 (tab.).— Gasca & Franco-Gordo 2014: 75 (list).— Lavaniegos 2014: passim.— Burridge et al. (2016): passim, table 2.— Espinosa-Leal & Lavaniegos 2016: 150 (tab.).— Lavaniegos 2020: passim.—Véliz et al. 2121: passim.

Metalycaea globosa Stephensen, 1925: 183–185 , 230 (tab.), fig. 71.— Nair & Jayalakshmy 1992: passim.— Nair 1993: 1171– 1176, figs 1–3.— Nair 1995: 7–8, pl. 1a, figs A1–A2; pl. 5a, 5b.— Vinogradov & Semenova 1996: 616.

Type material. Type material of Lycaea serrata could not be found in any major European institution and is considered lost. The type locality is the Bay of Bengal. Claus’s (1887) illustration of a male readily characterise this distinctive species .

Type material of synonyms. The three female syntypes of Metalycaea globosa are in the NHMD, all labelled “Type” in alcohol. The specimens were collected by the Thor from the Mediterranean Sea, stn. 112 [36°56’N 02°15’E], 25 mw, 27 June 1910 ( NHMD- 84411, previously CRU-6567); stn. 118 [41°00’N 06°43’E], 65 mw, 30 June 1910 ( NHMD- 86800, previously CRU-9301) and stn. 160 [35°59’N 28°14’E], 1000 mw, 1 August 1910 ( NHMD- 86799, previously CRU-9300). The specimen from stn. 118 is illustrated by Stephensen (1925). An examination of this material has proven that it is indistinguishable from mature female specimens of L. serrata .

Material examined. The type material of Metalycaea globosa as detailed above and the following. In NHMD: Mediterranean Sea , 9 males (7 lots) , Dana stns 1123 iv, 4050 v, 4060 and Thor stns 134, 144, 183, 339. N.E. Atlantic, 5 females (3 lots) Dana stns 4001 iv (228304), 4004 v (228306), 4005 x (228307). S.W. Atlantic, 20 females, male (3 lots), Dana stns 1231 iv (228245), 3997 iv-v (620062, 228297); additional Dana material from the Atlantic, 12 females, 1 male (10 lots) from stns 1145 vii, 1189, 1239, 1320, 1364, 3978 x, 3997iii, 3998 iii, 4001 iv, 4010 ii. Indian Ocean from Sumatra to South Africa, 55 females, 26 males (43 lots) , Dana stns 3814 i, 3850 i, 3850 iii, 3857 iii, 3893 iii, 3903 iv-v, 3915 iii, 3918 iii, 3919 iv, 3920 viii, 3921 ii-iii, 3921 vi, 3922 iii-iv, 3924 ii, 3925 ii-v, 3926 i, 3926 iv, 3928 i, 3928 v, 3929 iv, 3932 vi, 3937 ii, 3939 ii, 3938 ii, 3941 i-iv, 3956 iii, 3957 i, 3959 i-iii, 3962 iii, 3965 i-ii, 3971 ii-iii. Tropical Pacific, 22 females, 14 males (25 lots), Dana stns 3553 i, 3556 ii, 3558 vi-vii, 3561 v, 3563 ii, 3593 iii, 3616 v, 3620 iii, 3622 iii, 3623 iv, 3624 x, 3626 iv, vi, viii, ix, 3651 vi-vii, 3655 iv, 3722 iii, 3724 i, 3800 ii-iii, 3814 i. In SAM and SAMA (part), Meiring Naude collections from S.W. Indian Ocean, off South Africa, just north of East London, 4 females, 1 male (4 lots) , 244–0 m. In SAMA: Tasman Sea, off eastern Tasmania [42°47’50”S 148°50’E], 1100–0 m, 2 females , C12082. S.W. Atlantic , off Brazil [03°29.95’S 32°30.49”W], 5 juveniles (doubtful ID) , C12601. In USNM: N.W. Atlantic, from French Guiana in the south, north to Georges Bank , off Massachusetts, 6 females, 3 males (8 lots) , 108048–9, 1154681, 1241175–7, 1246985, 1246989. S.W. Atlantic , off Brazil [08°02’S 24°59’W], 64 m, 1 female , 1246981.

Diagnosis. Body length of mature females up to 16.0 mm and males up to 9.0 mm. Head of females ovalshaped, almost 2 x as deep as long, as long as first 4 pereonites combined. Head of males relatively smaller than females, 2 x as deep as long, almost as long as first 4 pereonites combined. Buccal mass protruded well below head. Callynophore of A1 of males without antero-distal corner; postero-distal corner small, rounded, partly over-lapping following article. Mature females with pereonites inflated, resembling transverse rollers (as in Iulopis ), progressively more raised dorsally; pleonites also with raised dorsal corners. Mature males and immature females with dorsal corners of pereonites 4–7 only slightly raised; pleonites 1–2 may also have slightly raised dorsal corners. G1 and G2 sub-chelate, G2 about 1.5 x as long as G1. G1 basis inflated anteriorly with evenly rounded anterior margin; carpus trapezoid, with obliquely excavate distal margin, with small, sharp, postero-distal tooth; postero-distal corner of propodus not produced posteriorly to dactylus; dactylus relatively long and slender, length about 0.8 x propodus. G2 carpus slightly less excavate than G1; propodus and dactylus like that of G1. P3–6 with relatively short, slender dactylus, those of P3 and P4 about 0.2 x propodus, or slightly less. P3 and P4 morphologically similar, P4 marginally longer than P3; merus slightly inflated anteriorly, slightly longer than propodus and about 0.5 x length basis; propodus slightly longer than carpus, with slight postero-distal excavation and slightly serrated margin. P5 of very large females like that of males, otherwise as follows; length about 1.2 x P4, 1.3 x P6; basis rectangular, relatively slender, length slightly more than 3 x maximum width; merus relatively long and slender, length about 1.6 x propodus, almost 0.7 x basis; carpus sub-equal in length to propodus. P5 of males; length almost 1.4 x P4, about 1.3 x P6; basis rectangular, relatively slender, length almost 3 x maximum width; merus with distinct anterior bulge, especially in mature specimens, length 1.4 x propodus, slightly more than 0.6 x basis; carpus also with distinct anterior bulge, sub-equal in length to propodus; propodus with slight serrations on anterior margin. P6 basis pear-shaped, especially in females where the length is about 1.4 x maximum width; merus length about 0.5 x basis, about 1.2 x propodus; carpus length about 0.8 x propodus; anterior margin of carpus and propodus, and antero-distal corner of merus, slightly serrated. P7 basis with bulging posterior margin, length about 1.8 x maximum width, about 0.7 x basis of P 6 in males, almost as long as basis of P 6 in females; length of remaining articles less than 0.2 x basis; dactylus degenerative or absent. U1 and U2 endopod not fused with peduncle. U1 peduncle length about 2.0 x exopod in females, slightly less in males; rami equal in length. Telson slightly longer than width at base, with evenly rounded, almost pointed apex.

Remarks. Lycaea serrata is the largest and one of the most distinctive species of Lycaea . Apart from the obliquely excavate carpus of G1 and G2, it is easily distinguished by a number of unusual characters. In particular, in mature females the pereonites are characteristically inflated resembling transverse rollers (similar to Iulopis ) and the dorsal corners of the pleonites are also significantly raised. In mature males, and to a lesser extent in juvenile males and females, some pereonites (usually 4–7) and the first two pleonites are carinate. Also, in mature males and very large females the merus and carpus of P5 is distinctly inflated. In addition, the propodus of P3 and P4 has a slight postero-distal excavation; the basis of P6 is pear-shaped and the distal articles of P7 are together much shorter than the basis, with a degenerative dactylus. The degree of the excavation of the carpus of G1 and G2 can vary slightly but is always more extreme in G1. The discovery of L. proserrata amongst collections identified as L. serrata indicate that more species may be determined amongst the “ serrata ’ group with a more detailed analysis of the gnathopod morphology and other characters. Its similarity to L. proserrata is discussed under that species.

A salp associate has not been recorded for this species.

Distribution. This appears to be mainly a tropical species having been recorded from the tropical regions of all three oceans and the Mediterranean Sea. It has also been recorded from the warmer parts of the North Atlantic, as far as 41°N.

Figures

FIGURE 18. Lycaea serrata Claus, 1879. Female, 11.5 mm (ovig.), USNM 1154681. Scale bars = 1.0 mm (habitus); 0.5 mm (G1–P7, Us); 0.2 mm (A1).

FIGURE 19. Lycaea serrata Claus, 1879. Male, 7.0 mm, USNM 1246989. A1 and A2 from male, 8.0 mm, NHMD 228122. P5-♀ from female, 15.7 mm, SAMA C12082. Scale bars = 1.0 mm (habitus, P5-♀); 0.5 mm (A2, G1–P7); 0.2 mm (A1, Us).