Mimonectes loveni Bovallius, 1885

Zeidler, Wolfgang, 2012, A review of the hyperiidean amphipod families Mimonectidae and Proscinidae (Crustacea: Amphipoda: Hyperiidea: Scinoidea) 3533, Zootaxa 3533, pp. 1-74 : 20-27

Mimonectes loveni Bovallius, 1885

( Figs. 7–11)

Mimonectes loveni Bovallius, 1885: 3–11 , pl. 1, figs. 1–11; pl. 2, figs. 15–20; pl. 3, figs. 21–27.— Bovallius 1887 a: 15. Bovallius 1889: 60–65, pl. 5, figs. 1–20. Vosseler 1901: 93. Woltereck 1904a: 622–625, fig. 2. Woltereck 1904b: 629 (key). Stephensen 1923: 6. Schellenberg 1927: 600, fig. 9. Stephensen & Pirlot 1931: 506–516, figs. I.1a,b, 2a,b; II.1–3; III & IV. Stephensen 1932: 375 (list). Stephensen 1933: 66. Pirlot 1939: 20–21. Shoemaker 1945: 219–221, fig. 25. Bulycheva 1955: 1048 (table). Vinogradov 1957: 166, 179 (table), [English]. Vinogradov 1960: 218. Vinogradov 1964: 126. Vinogradov 1970: 385 (table). Vinogradov et al. 1982: 113 (key), 116–118, fig. 48. Barkhatov & Vinogradov 1988: 245 (table). Vinogradov & Semenova 1996: 617, 619. Vinogradov 1999: 1147 (table), 1171–1172, fig. 4.44. Vinogradov et al. 2004: 9, 25 (table). Browne et al. 2007: 819 (table), fig. 4. Zeidler & De Broyer 2009: 71. Mori et al. 2010: 8 (list).

Sphaeromimonectes cultricornis Woltereck, 1906: 868–869 , fig. 5a.— Woltereck 1927: 83–84, fig. 26.

Parascina Chevreusi Pirlot, 1929: 56–57 .— Pirlot 1930: 7–8. Barnard 1932: 253.

Mimonectes chevreuxi — Stephensen & Pirlot 1931: 528–530, figs. I.1–4; II.2–4; XI. Barnard 1937: 179.

Parascina fowleri [mis-identification]— Chevreux 1905; 1 (part). Tattersall 1906: 6. Stephensen 1918: 17–18 (part), figs. 5–6. Chevreux 1919: 9 (part). Stephensen 1923: 7 (part). Schellenberg 1927: 502 (part).

Proscina magna Stephensen & Pirlot, 1931: 545–500 , figs. 17–18.— Pirlot 1932: 23, fig. 15. Pirlot 1939: 25–28, pl. 2, fig. 4. Vinogradov 1957: 210, fig. 14. Vinogradov 1960 a: 222. Thurston 1976: 384–385 (table), 391–392. Vinogradov et al. 1982: 123 (key), 125–126, fig. 53. Shih & Hendrycks 1996: 591, 595, 596 (table), 599 (table). New synonymy.

Type material. Bovallius (1885) gives the type locality as “the Atlantic”, but does not specify the sex or number of specimens examined, although he gives a size range of 18–28 mm, indicating that he had more than one specimen, and illustrates a mature female. Later (1889) he gives the distribution as “northern temperate and tropical regions of the Atlantic”.

The ZMUC and NRS has several specimens (all females) that date from the time of Bovallius, and that could be considered type material of M. loveni . These are listed by Stephensen and Pirlot (1931), and I have also examined all but one of the thirteen lots enumerated by them. None are labelled as types, which is typical of Bovallius’s material, and only nine are labelled as having been determined by Bovallius. Of these, two are labelled (by Bovallius) as “ Mimonectes sphaericus ”, two as “ Mimonectes steenstrupi ” and two as “ Mimonectes sp ” and must be disregarded as type material. Thus, only three lots remain that are here considered to represent type material of M. loveni . One of these ( ZMUC CRU-7147; spec. 1 of Stephensen & Pirlot), from the tropical Atlantic (02°N 25°W), is in reasonable condition, although in three pieces and with the mouthparts intact. It is illustrated here (fig. 7) and designated the lectotype. However, the mouthparts illustrated by Bovallius (1885: pl.1, figs. 3–5) could not have come from this specimen. The other two lots, here designated paralectotypes, are in the NRS and consist of one damaged specimen (No. 1345; spec. 4 of Stephensen & Pirlot), from off Barbados (13°N 59°W), and one lot of dissected bits (No. 1746; spec. 12 of Stephensen & Pirlot), from the North Atlantic (46°N 18°W), probably the remains of the specimen used by Bovallius to illustrate the mouthparts.

Type material of synonyms. The holotype of S. cultricornis is in the MFN (21336). It is a mature female measuring about 20 mm, from the South Atlantic (12°11’S 06°16’W), collected by the Gauss, Deutschen Sud- Polar Expedition, 4 September 1903. I have examined this specimen and it is clearly the same as M. loveni .

Parascina chevreuxi was a new name introduced by Pirlot (1929) for some specimens (male) previously determined as Parascina fowleri Stebbing, 1904 (= M. gaussi ). Pirlot did not specify type material but refers to Stephensen’s (1918) description and figure of a male specimen of Parascina fowleri . According to Stephensen & Pirlot (1931) “La forme décrite par STEPHENSEN (1918) est considérée par PIRLOT (1929) comme le type de P. Chevreuxi ”. The specimen in question is in the ZMUC (CRU-20465), collected by the Thor from south-west of Ireland (50°25’N 12°44’W), Thor stn. 62, 1500 mw, 5 June 1906. I have examined this specimen and confirmed it to be a male (about 7 mm) of M. loveni . The Aquarium-Muséum de l’Université de Liège, Belgium, also has some specimens labelled “ Parascina fowleri ” (RE 11977) and “ Parascina chevreuxi’ (RE 11978) that were most likely examined by Pirlot (1929).

The holotype of P. magna is in the MOM (3721 30), as detailed previously.

Material examined. Types. Lectotype and paralectotypes of M. loveni (designated here), the holotype of S. cultricornis and the type of Parascina chevreuxi , as detailed above.

Other material examined. N.E. Atlantic: Female ( ZMUC); south-west of Greenland (58°N 28°W), “Olrik”, 7 June 1852. Female ( ZMUC, CRU-9503); west of Bay of Biscay (46°N 18°W), “Hygom”, 1856. Female

( ZMUC); north of the Azores (45°N 26°W), “Hygom”. Female ( ZMUC); north of the Azores (43°N 23°W), “Hygom”, 18 April 1857 . Three females ( ZMUC); between Canary & Cape Verde Islands (25°N 23°W), “Hygom”, 1857. Female ( ZMUC); west of Cape Verde Islands (13°N 34°W), 9 September 1863 . Four males ( ZMUC); south of Iceland (61°30’N 17°08’W), Thor stn. 183, 1800 mw, 11 July 1904 . Male ( ZMUC); south-west of Ireland (50°25’N 12°44’W), Thor stn. 62, 1500 mw, 5 June 1906 . Female ( ZMUC); north of Cape Verde Islands (21°57’N 22°58’W), Dana stn. 1157 V, 5000 mw, 27 October 1921 . Male & two males ( ZMUC); south-west of Cape Verde Islands (12°11’N 35°49’W), Dana stns. 1165 III & X, 600 & 1000 mw respectively, 9 November 1921 . Male ( ZMUC); west of Sierra Leone (08°26’N 15°11’W), Dana stn. 4003 VIII, 600 mw, 9 March 1930 . Male & juv. female & juv. ( ZMUC); off Senegal (13°31N 18°03W), Dana stns. 4005 III, VI & VII, 3000, 1000 & 1000 mw respectively, 12 March 1930 . Male ( ZMUC); off Mauritania (21°40’N 18°00’W), Dana stn. 4008 II, 600 mw, 16 March 1930 . Juv., ( USNM 1149247 ); “E. coast of United States and Bermuda ”, R/ V Bache, 1914. N.W. Atlantic: Two females ( NRS, No. 1344 & 1345); near Barbados (13°N 59°W), 1883. S.E. Atlantic: Two males & two females, male ( ZMUC); off South Africa (30°15’S 13°15’E), Dana stns. 3978 VII & VIII, 4000 & 3000 mw respectively, 13 February 1930 . Female ( ZMUC); off South Africa (23°26’S 03°58’E), Dana stn. 3980 X, 2000 mw, 17 February 1930 . Female & juv. ( ZMUC); near St. Helena (15°41’S 05°50’W), Dana stns. 3996 II & III, 3000 & 2000 mw respectively, 25 February 1930 . Juv. male & two females, juv. ( ZMUC); north of St. Helena (07°S 08°48’W), Dana stns. 3998 VII & VIII, 5000 & 4000 mw respectively, 1 March 1930 . Male & two females ( ZMUC); north-east of Ascension Island (03°45’S 10°00’W), Dana stns. 3999 I & III, 1000 & 300 mw respectively, 2 March 1930 . Female , male, juv. & female, male & female & four females, two males ( ZMUC); south of Liberia (00°31’S 11°02’W), Dana stns. 4000 VII, IX, X & XI, 5000, 3000, 3000 & 1000 mw respectively, 4 March 1930 . N.E. Pacific: Juv. male ( ZMUC); Gulf of Panama (06°48’N 80°33’W), Dana stn. 1208 VI, 2500 mw, 16 June 1922 . Female ( ZMUC); near the Galapagos Islands (02°52’N 87°38’W), Dana stn. 3556 II, 2000 mw, 14 September 1928 . Male ( SAMA, C6865 ); (41°1.2’N 164°58.3’W), 1200 m, ex. M. Galbraith, 30 June 1997 . Juv. female ( SAMA C6866 ); south-west of Vancouver Island (48°0.77’N 126°17.42’W), 1000– 600 m, ex. M. Galbraith, 18 September 2006 . Male ( SAMA C6867 ); west of southern tip of Moresby Island, B.C. (51°36’N 133°51’W), 250 m, ex. M. Galbraith, 4 June 2007 . Male ( SAMA C6868 ); off Queen Charlotte Island (52°29’N 138°44’W), 1500– 1000 m, ex. M. Galbraith, 28 September 2001 . N.W. Pacific: Juv. ( SAMA C7573 , ex. JAMSTEC); Sagami Bay , Japan (34°41’N 139°49’E), R/ V Kaiyo stn. IO60325A-2 (cruise 06–03), 300–350 m, col. D.J. Lindsay, 25 March 2006 . Female ( SAMA C6869 , ex. JAMSTEC); Japan Trench (41°00.5’N 144°41.5’E), 566 m, ROV HyperDolphin dive 99, 23 April 2002 . Female ( SAMA C6870 , ex. JAMSTEC); Japan Trench (38°20.04’N 143°55.03’E), 780 m, ROV HyperDolphin dive 83, 29 April 2002 . S.E. Pacific: Male & squashed spec. ( ZMUC); south-east of Panama (00°18’S 99°07’W), Dana stns. 3558 II & III, 2000 mw, 18 September 1928 . Female & two juv. ( ZMUC); south-east of Galapagos Islands (04°20’S 116°46’W), Dana stns. 3561 III & IV, 3000 & 2000 mw respectively, 24 September 1928 . S.W. Pacific: Male ( ZMUC); near Fiji (17°27’S 179°33’E), Dana stn. 3593 II, 2700 mw, 10 November 1928 . Female ( ZMUC); west of Kermadec Islands (27°00’S 177°41’W), Dana stn. 3626 VIII, 1500 m, 13 December 1928 . Two males & male ( ZMUC); north of New Zealand (30°08’S 176°50’E), Dana stns. 3627 II & IV, 4000 & 2000 mw respectively, 14 December 1928 . Two males ( ZMUC); east of New Zealand (41°47’S 176°55’E), Dana stn. 3640 VIII, 2000 mw, 7 January 1929 . Male ( ZMUC); east of New Zealand (43°40’S 176°36’E), Dana stn. 3641 II, 100 m, 8 January 1929 . Male & male ( ZMUC); east of New Zealand (46°43’S 176°08.5’E), Dana stns. 3642 II & IV, 2500 & 1500 mw respectively, 9 January 1929 . Female, male ( ZMUC); Tasman Sea (33°26’S 157°02’E), Dana stn. 3656 II, 4000 mw, 29 January 1929 . Male ( ZMUC); Tasman Sea (33°33’S 154°04’E), Dana stn. 3663 II, 4000 mw, 23 February 1929 . Indo-Pacific: Male ( ZMUC); South China Sea (06°55’N 114°02’E), Dana stn. 3688 IV, 2000 mw, 8 April 1929 . Two males ( ZMUC); South China Sea (07°13.5’N 111°49’E), Dana stn. 3689 II, 9 April 1929 . E. Indian: Male & male ( ZMUC); south of Sri Lanka (05°21’N 80°38’E), Dana stns. 3909 II & IV, 4000 & 3000 mw respectively, 22 November 1929 . Male ( ZMUC); south of the Maldives (01°45’N 71°05’E), Dana stn. 3917 II, 3700 mw, 15 December 1929 . W. Indian: Female ( ZMUC); north of Madagascar (11°18’S 50°03’E), Dana stn. 3933 V, 2000 mw, 20 December 1929 .

Diagnosis. Females: Body length up to 30 mm, reaching sexual maturity at about 20 mm. Pereon of mature specimens greatly inflated due to enlarged pereonites 1–4 (5). Antennae 1 as long as head and first 1–5 pereonites combined (medially). Antennae 2 much reduced in length. Gnathopod 1; basis slightly shorter than remaining articles combined; carpus length about 1.3x propodus; both armed with relatively long, fine setae on posterior margin, also on anterior margin, and medially on propodus; dactyl very short. Gnathopod 2 slightly longer and marginally more slender than G1; basis slightly longer than remaining articles combined; carpus slightly shorter than propodus, both armed with setae as in G1 but fewer; dactyl very short. Pereopods 3 & 4 similar in structure and length; basis length 2.3–2.5x merus; merus expanded distally with antero-distal and postero-distal corners slightly produced over carpus; carpus length 1.5–1.7x merus; propodus marginally longer than merus; dactyl very short; all articles (except dactyl armed with short, fine setae on posterior margin and sometimes also on anterior margin (except basis). Pereopod 5; length about 0.9–1.1x P4; basis length almost twice merus; merus expanded distally with antero-distal and postero-distal corners marginally produced; carpus length 1.3–1.5x merus; merus and carpus relatively broader in immature specimens (fig. 9); propodus length 0.6x carpus; dactyl relatively short or, in immature specimens, can be long and thin, up to 0.5x length propodus, inserted on anterior corner of propodus (fig. 9); articles with setae as for P3 & 4. Pereopod 6; length about 0.8–0.9x P5; merus length varies from about 0.8x basis (mature spec., fig. 10) to about 0.5x basis (immature spec.); similarly carpus length varies from 0.7x to slightly longer than merus; propodus length 0.6–0.7x carpus; dactyl very short, curved, almost retractile, inserted on anterior corner of propodus; anterior margin of merus and carpus and both margins of propodus armed with short setae, the distal ones on propodus distinctly curled. Pereopod 7 similar in length to P6; merus length varies from about 0.3x basis (immature spec., fig. 9) to about 0.6x basis (mature spec., fig. 10); similarly carpus length varies from slightly longer than (mature spec., fig. 10), to about 2.4x length merus (immature spec., fig. 9); propodus length about half carpus; merus and carpus much broader in immature specimens; dactyl very short but not as short as for P6, curved, inserted on anterior corner of propodus; articles armed with short setae as for P6. Uropoda with relatively slender peduncles and rami; all with inner ramus distinctly longer than peduncle or outer ramus. Uropod 1; inner ramus length 1.8x outer; and 1.6x peduncle. Uropod 2; inner ramus length 1.3x outer; and 1.7x peduncle. Uropod 3; inner ramus length 1.3x outer and peduncle; peduncle width about half length. Telson triangular; length about 0.4x peduncle of U3.

Males: Like females except for the following. Largest male recorded only 12 mm, reaching sexual maturity at about 11 mm. Pereon slightly arched, oval-shaped from dorsal aspect. Antennae 1 as long as head and first four pereonites combined; peduncular articles and callynophore relatively broader. Antennae 2 reduced in immature specimens, about 0.5–0.7x A 1 in more mature specimens. Gnathopod 2; basis slightly shorter than remaining articles combined. Pereopod 5 slightly longer than P4; propodus length almost 0.8x carpus. Pereopod 6; length 0.9x P5; merus length about 0.4x basis; carpus length about 1.3x merus; propodus length 0.6x carpus. Pereopod 7 similar in length to P6; merus length 0.3x basis; carpus length about 2.3x merus. Uropod 1; inner ramus length almost twice outer, and 1.8x peduncle. Uropod 2; inner ramus length 1.4x outer, and 1.7x peduncle. Uropod 3; inner ramus length 1.5x outer, and 1.3x peduncle; peduncle width slightly more than half length.

Colour, according to Vinogradov and Semenova (1996), “males are translucent rose-red or dark red; females are colourless or translucent with dark-rose spots and carmine eyes”. Bovallius (1885) says “yellowish brown”.

Remarks. This is the largest species in the genus, most readily distinguished from its congeners by the simple, hirsute gnathopods, and the relatively short dactyls. In having gnathopods without processes, or an excavation on the propodus, this species resembles M. spandlii and M. colemani sp. nov., but in those species the dactyls are much stronger, and in M. spandlii the merus of pereopods 3–7 is only slightly longer than the ischium.

In this species the pereon of females is only grossly inflated in very mature specimens, similar to that found in Archaeoscina . Immature specimens only have a slightly inflated pereon, similar to males, even in relatively large specimens. One specimen from the Japan Trench (SAMA C6869), a female measuring 21.5 mm, is still immature, judging by the under-developed oostegites, yet the pereon is only marginally inflated.

In addition to the above, there are other differences in morphology between mature and immature specimens, as noted in the diagnosis. In particular immature females tend to resemble males in the relative lengths of the pereopods with pereopod 5 slightly longer than pereopod 4, with slightly broader articles and a marginally longer dactyl. One characteristic feature of this species, especially for immature females, is the relatively narrower articles of pereopod 6, and the relatively broad basis, merus and carpus of pereopods 5 & 7, especially the carpus of pereopod 7, which can be relatively large and swollen (fig. 9). Also, in larger females the articles of pereopods 5–7 are relatively more slender, and the telson is marginally shorter (fig. 10). In some specimens the dactyls of pereopods 3–5 can be relatively longer, especially that of pereopod 5 (fig. 9). Again this seems to be a character of immature specimens.

One lot of specimens, from the south-east Atlantic ( Dana stn. 3978 VIII) contains a male and female with characters consistent with M. loveni , except that the pereopods are relatively longer and more slender, especially pereopods 6 & 7, which are as long, or slightly longer than, pereopod 5.

The moderately large specimen from the Japan Trench, mentioned above, was captured by submersible while attached to the narcomedusa Solmissus sp.

Distribution. This is one of the more common species of Mimonectes , having been found in all the world’s oceans except the Mediterranean Sea. In the Atlantic previous records are mainly from the northern part, from as far north as 63°19’N ( Stephensen 1933), with few records from the south; all from tropical regions. In the Pacific it has been recorded from the Kuril-Kamchatka region, the tropics and south to 43°S ( Vinogradov & Semenova 1996). It seems to be relatively rare in the Indian Ocean with only two previous literature records, from the Arabian Sea ( Barnard 1937), and from the south-east and north-eastern parts ( Vinogradov 1964). The Dana collected this species from all major oceans providing many range extensions, particularly in the south-east Atlantic to 30°15’S (stn. 3978), and the tropical and South Pacific, with new records for the South China Sea (stns. 3688 & 3689) and the Tasman Sea (stns. 3656 & 3663). The latter is also a new record for Australian waters. In the Indian Ocean the Dana only collected it from three stations, from tropical regions, indicating that this species may be less common there than in the Atlantic or Pacific.

According to Vinogradov et al. (1982) this species is most commonly found in the 200–1000 m range, and sometimes occurs near the surface. The Dana collected most specimens of this species with 2000–5000 mw, indicating that it probably prefers deeper waters.