Megalanceola stephenseni (Chevreux)

Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 2000, pp. 1-117 : 76-78

Megalanceola stephenseni (Chevreux)

( Fig. 27)

Lanceola sp. Stebbing 1888: 1308 , fig. 27. Lanceola stephenseni Chevreux, 1920: 4–7 , figs 1–3. Chevreux 1935: 137–139, pl. 14, figs 9,10,15. Megalanceola stephenseni - Pirlot, 1939: 9–12, pl. 1, figs 1–4. Shoemaker 1945: 212, 215, fig. 21. Vinogradov et al.

1982: 82, fig. 25. Zeidler 1991: 128, fig. 1; 1992: 91-92, fig. 5. De Broyer & Jazdzewski 1993: 110. Gates et al.

2003: 319. Megalanceola terra-novae Pirlot, 1935: 2–8 , figs 1–4. Herring 1981: 169, fig. 2d.

Type material. The unique type is in the MOM (37 1081) as detailed above.

Type material of synonyms. The unique type of M. terra-novae is in the MOM (37 2104) on microscope slides. It is a mature female measuring 55 mm in length, from the North Atlantic, off Nova Scotia [43°26’N 59°03’W]; Hirondelle II Stn. 3452, 0–3000 m, 28 Aug. 1913. Pirlot (1939) realised that this species is synonymous with L. stephenseni and transferred the latter to his new genus, a decision supported by subsequent researchers.

Material examined. North-West Pacific: Female ( ZMUC); N. of Irianjaya [03°40.5’N 137°53’E]; Dana Stn. 3751 VII, 3000 mw, 12 Jul. 1929 . South-East Pacific : Male ( ZMUC); S.E. of Panama [00°18’S 99°07’W]; Dana Stn. 3558 II, 2000 mw, 18 Sept. 1928 . South-West Pacific : Female ( AM P39758); Tasman Sea [33°28’S 152°33’E]; Stn. JP 77-26, 0–1000 m, 14 Dec. 1977 . Female ( AM P40876); Tasman Sea [28°05.76’S 163°06.04’E]; R.V. Franklin Stn. F25, 1051 m, 5 May 1989 . Female ( AM P66430); Tasman Sea [32°36’23”S 167°50’35”E]; col. P.B. Berents, 1345 m, 30 May 2003 . Male ( AM P66432); Tasman Sea [33°29’24”S 170°00’43”E]; col. P.B. Berents, 1230m, 1 Jun. 2003 . Female ( AM P66440); Tasman Sea [34°16’29”S 168°24’05”E]; col. P.B. Berents, 1249 m, 2 Jun. 2003 . Indo-Pacific : Female ( MNHN); Makassar Strait / Celebes Sea [00°04.9’N 119°47.8’E]; CORINDON 2– Stn. 231, 980– 1080 m, 4 Nov. 1980 . Female ( MNHN); Makassar Strait [01°57.5’S 119°02.0’E]; CORINDON 2– Stn. 281, 1120– 1150 m, 8 Nov. 1980 . Male , female ( MNHN); Mindoro Strait / South China Sea [13°37’N 120°33’E]; MUSORSTOM 2– Stn. 50, 810– 820 m, 27 Nov. 1980 . Male , female ( MNHN); near Mindoro Strait / South China Sea [13°47’N 120°30’E]; MUSORSTOM 3– Stn. 106, 640– 668 m, 2 Jun. 1985 . Two females ( MNHN); near Mindoro Strait / South China Sea [13°34’N 120°29’E]; MUSORSTOM 3– Stn. 114, 1000–1040m, 2 Jun.1985 . Southern Ocean : Juvenile ( SAMA C6270 ); near Macquarie Is. [54°53’S 157°56.9’E]; F.R.V. Southern Surveyor, 1646 m, 24 Jan. 1999 .

Diagnosis. Body length of females up to 95 mm, of males up to 56 mm. Body massive with dorsoventrally broadened pereon; pereon and pleon usually in curled position. Cuticle thick, smooth. Head with short rounded rostrum. Eyes located on ventro-lateral corner of head, not prominent in preserved specimens. Antennae 1 as long as head and first pereonite combined; terminal article subequal in length to preceding one.

Antennae 2 length about 2.4–2.5x A1. Gnathopod 2; distal margin of carpus slightly broadened; similar to Lanceola . Pereopods relatively slender; all with basis abruptly narrowed proximally with small anterior hump; more prominent in P4–6. Pereopod 3 similar to P4; basis length almost twice merus; carpus slightly longer than merus; propodus slightly longer than half propodus; dactylus not retractile, relatively straight, length about 0.2x propodus. Pereopods 5–7 with retractile, fully hooded dactyls. Pereopod 5; length about 1.2x P4; basis length 1.7x merus; carpus and propodus equal in length, only slightly shorter than merus. Pereopod 6 similar in structure and length to P5. Pereopod 7; length 0.8x P6; similar in structure to P6 but basis relatively shorter. Peduncles and rami of urosome relatively broad. Peduncle of U1 slightly shorter than limit of peduncle of U2. Uropod 3; peduncle width 0.6x length. Telson twice as long as width at base; reaching to middle of inner ramus of U3.

Colour of living specimens not recorded.

Remarks. This is one of the largest species of Hyperiidea , exceeded only by some species of Cystisoma (Cystisomatidae) . It appears to be a relatively rare species, only having been recorded in the literature on seven previous occasions from a total of twenty-seven females and four males (including the type). Regarding Stebbing’s (1888) record of Lanceola sp. , the figures accompanying Stebbing’s remarks made by Willemoes- Suhm, are rather crude but seem to represent this species. Stebbing did not see this specimen as it had presumably become lost.

Herring (1981) records secretory bioluminescence in a juvenile female from the “Southern Ocean”. Sites of luminescence were observed near the tip of the pereopods and the first two uropoda.

Distribution. Previously recorded from the Indo-Pacific ( Stebbing 1888, Zeidler 1991), the Tasman Sea ( Zeidler 1992), the North Atlantic near the Azores, Nova Scotia and Bermuda ( Chevreux 1920, Pirlot 1935, Shoemaker 1945) and from the Southern Ocean ( Herring 1981). The current collection includes additional records for the Tasman Sea, Southern Ocean and new records for the equatorial west and east Pacific. It remains to be recorded from the Indian Ocean. Zeidler (1991) recorded it from 640–1150 m and later (1992) from 0–1051 m. Most other records are from around 1000 m depth, with possibly the deepest 0–3000 m ( Chevreux 1920, Pirlot 1935).