Lanceola loveni antarctica Vinogradov, 1962

Zeidler, Wolfgang, 2021, Redescription of two rare, deep-sea species of hyperiidean amphipod, Lanceola loveni antarctica Vinogradov, 1962 and L. sphaerica Vinogradov, 1970 (Crustacea: Amphipoda: Hyperiidea: Lanceolidae), Zootaxa 5067 (1), pp. 106-114 : 107-111

Lanceola loveni antarctica Vinogradov, 1962

( Figs. 1 , 2 )

Lanceola loveni antarctica Vinogradov 1962: 6–10 , figs 1, 2, 4.— Hurley 1969: 33.— Vinogradov et al. 1982 / 1996: 64 /74–75, fig. 13.— De Broyer & Jażdżewski 1993: 109.—Zeidler 2009: 16–17.— Zeidler & De Broyer 2009: 28 .— Zeidler & De Broyer 2014: 304.— Zeidler 2019: 512 .

Material examined. Southwest Atlantic. Female ( USNM 1089979 ), Scotia Sea , near Sandwich Islands , Cruise 8, station 575 [54°33’S 24°19’W], 1867 m, no date; female ( USNM 1090242 ), Cruise 8, station 640 [58°10’S 23°39’W], 1537 m, no date. Southeast Pacific. Female ( USNM 1013495 ), western Drake Passage , Cruise 10, station 811 [64.767°S 78.1°W], 461–1263 m, 30 October 1963 (figured here). Southern Ocean , Pacific Sector. Female ( USNM 1090243 ), Cruise 11, station 890 [59°39’S 114°37’W], 595–609 m, 3 January 1964. Strait of Magellan. Male ( USNM 1090255 ), Cruise 11, station 957 [53°’ S 75°00’W], 458–732 m, 5 February 1964 ( Figs 1 , 2 ) .

Type material. Lanceola loveni antarctica was described from seven specimens, 7–27 mm, collected by the Russian research vessel Ob from the following five stations between the Antarctic Continent and the Antarctic Polar Front. From the Indian Ocean Sector : station 36, off Wilkes Land [62°55’S 118°52’E], 0–3,700 m; station 105, near the Davis Sea [55°40’S 106°13’E], 240–600 m; station 111 [64°25’S 92°52’E], 0–2,000 m; station 285 [59°29’S 97°08’E], 0–4500 m. From the Pacific Sector : station 57, near the Balleny Islands [64°03’S 161°59’E], 0–2,000 m and 0–3,000 m. The syntypes from stations 36 and 57 are in the Zoological Museum of the Moscow State University (Mb–1049 and 1050). A female is illustrated by Vinogradov (1962) .

Description of male 25 mm ( Fig. 1 ). Distal corner of pereonites 6 and 7, pleonites and first urosomite produced into small, distinct, dorsal denticles. Head with relatively long, rounded rostrum. Eyes very small, reniform, without crystalline cones. A1 slightly longer than head and first pereonite combined. A2 length 2 x A1, almost as long as head and first two pereonites combined. G1; basis relatively slender, both margins fringed with long setae, about as long as remaining articles combined; carpus length 0.6 x basis, distal margin width about 1.5 x proximal margin of propodus; propodus conical-shaped, length 1.6 x proximal width; dactylus very slender, almost as long as 0.5 x propodus. G2 with relatively long, slender articles, much longer than G1; basis length about 1.5 x carpus; propodus gradually tapering to narrow distal margin, length about 0.8 x carpus; dactylus inserted terminally to propodus, length slightly less than 0.3 x propodus. P3 length about 1.2 x G2, with similar slender articles; basis length 1.5 x merus; carpus length 0.8 x merus; propodus slightly longer than carpus; dactylus inserted terminally to propodus, length marginally less than 0.2 x propodus. P4 morphologically similar to P3, marginally shorter, with slight differences in relative lengths of articles as follows: basis length 1.3 x merus; carpus length marginally more than 0.8 x merus; propodus and carpus sub-equal in length. P5–7 all with relatively long, slender articles and fully retractile, hooded dactyls. P5 length 1.2 x P4; basis length almost 1.5 x merus; carpus length 0.8 x merus, 1.4 x propodus; dactylus without setae. P6 length 1.2 x P5, almost as long as pereon and first two pleonites combined; basis length about 1.3 x merus; carpus length almost 0.8 x merus, 0.8 x propodus; dactylus inserted in slight bulge of propodus, fringe of short setae on anterior margin. P7 about 0.5 x P6 length; basis length 1.6 x merus; carpus marginally shorter than merus, about 0.8 x propodus; dactylus with fringe of short setae on anterior margin. Urosome with relatively slender peduncles and rami. Rami of all uropoda sub-equal in length. Peduncle of U1 marginally exceeds limit of peduncle of U2. Peduncle length of U1 = 1.8 x rami, of U2 = 1.5 x rami, of U3 = 1.3 x rami. Telson acute, apex rounded; length about 1.3 x width at base, reaching to about middle of peduncle of U3.

Description of female 26 mm ( Fig. 2 ). Distal corner of pereonites 6 and 7, pleonites and first urosomite produced into small, distinct, dorsal denticles. Head with short, rounded rostrum. Eyes very small, reniform, without crystalline cones. A1 slightly longer than head and first pereonite combined. A2 length 2.4 x A1, slightly longer than head and first two pereonites combined. G1; basis relatively slender, fringed with long setae on both margins, about as long as remaining articles combined; carpus length 0.5 x basis, distal margin width about 1.4 x proximal margin of propodus; propodus conical-shaped, length 1.6 x proximal width; dactylus missing. G2 with relatively long, slender articles, much longer than G1; basis length about 1.8 x carpus; propodus gradually tapering to narrow distal margin, length almost 0.8 x carpus; dactylus inserted terminally to propodus, length slightly less than 0.3 x propodus. P3 slightly longer than G2, with similar slender articles; basis length 1.6 x merus; carpus length 0.8 x merus; propodus slightly longer than carpus; dactylus missing. P4 morphologically similar to P3 but marginally longer, with slight differences in relative lengths of articles as follows: basis length about 1.3 x merus; carpus slightly shorter than merus; propodus slightly longer than carpus; dactylus missing. P5–7 all with relatively long, slender articles and fully retractile, hooded dactyls. P5 length almost 1.2 x P4; basis length 1.5 x merus; carpus length almost 0.8 x merus, 1.2 x propodus; dactylus without setae. P6 length 1.2 x P5, almost as long as pereon and pleon combined; basis length about 1.3 x merus; carpus length 0.8 x merus; propodus as long as merus; dactylus inserted in slight bulge of propodus, too dense to determine presence of setae. P7 almost 0.5 x P6; basis length 1.7 x merus; carpus marginally shorter than merus, about 0.8 x propodus; dactylus without fringe of short setae on anterior margin. Urosome with relatively slender peduncles and rami. Rami of all uropoda sub-equal in length. Peduncle of U1 slightly exceeds limit of peduncle of U2. Peduncle lengths of U1 = about 2.0 x rami; of U2 = 1.6 x rami; of U3 = 1.4 x rami. Telson acute, with rounded apex; length about 1.4 x width at base, reaching to about the middle of peduncle of U3.

The main differences from the male, apart from minor differences in the relative lengths of articles, are as follows: i) the head has a shorter rostrum; ii) A2 are relatively longer; iii) the basis of G2 is relatively longer; iv) P3 is slightly shorter than P4; v) P5–7 are relatively marginally longer compared to the body length; vi) the dactylus of P7 is without setae (maybe also P6, not discernable); and vii) the peduncles of U1–3 are marginally longer compared to the rami.

Remarks. The most obvious difference from the typical form is that individuals of all ages have the distal corner of the pleonites produced into small dorsal denticles, similar to L. serrata Bovallius, 1885 , but that species is distinguished by the much longer telson (slightly longer or shorter than the peduncle of U3) and the wide distal margin of the carpus of G1. Other distinguishing characters from the typical form are as follows: i) the head has a more prominent rostrum, especially for males; ii) the carpus and propodus of G1 are slightly more elongate; iii) the propodus of P6 is more club-like, similar to L. loveni grossipes Shoemaker, 1945 ; iv) the telson is marginally more narrow; and v) there are also minor differences in the relative lengths of appendages and articles, although these may be within the confines of specific variability. The relatively long rostrum of the male, illustrated here, is particularly distinctive and may be an unusual feature of this specimen. Whether or not it is a genuine male character can only be determined with the discovery of more material.

Vinogradov et al. (1982, 1996) list L. australis Stebbing, 1888 as a questionable synonym of this species, probably based on the presence of dorsal denticles on the pleonites. However, an examination of the type material in the Natural History Museum, London has confirmed that it is a synonym of L. serrata (Zeidler 2009) .

Distribution. This species seems to be restricted mainly to the Antarctic Sectors of the Southern Ocean. It has been recorded in the Atlantic Sector from the Scotia Sea to the Drake Passage and from there to the Pacific Sector as far as 114°37’W, and in the Indian Ocean Sector from off Wilkes Land and near the Davis Sea; from various hauls from 4,500 m to the surface, as detailed above. The male, illustrated here (USNM 1090255), from the Strait of Magellan, is a new distribution record for this species.

Figures

FIGURE 1. Lanceola loveni antarctica Vinogradov, 1962: male 25 mm (USNM 1090255), Strait of Magellan, 458–732 m. Scale bars: 1.0 mm (G1 & G2); 2.0 mm (remainder). Enlargements all same magnification.

FIGURE 2. Lanceola loveni antarctica Vinogradov, 1962: female 26 mm (USNM 1013495), western Drake Passage, 461–1263 m. Scale bars: 1.0 mm (G1 & G2); 2.0 mm (remainder). Enlargements all same magnification.