Mimonecteola carlsbergi, Zeidler, 2009

Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), Zootaxa 2000, pp. 1-117 : 110-112

Mimonecteola carlsbergi sp. nov.

( Figs 44 & 45)

Material examined. Holotype. Female , 12.8 mm ( ZMUC CRU–9937); South Atlantic, off South Africa [30°15’S 13°15’E]; Dana Stn. 3978 VIII, 3000 mw, 13 Feb. 1930.

Paratype. Female (damaged), approx. 15.0 mm ( ZMUC CRU–9938); S.W. Indian Ocean, off South Africa, between Cape Town and Durban [34°56’S 36°31’E]; Galathea Stn. 180, 7442–7507 mw, 25 Jan. 1951 .

Description of holotype. The antennae and mouthparts were not dissected from the type but a description of these appendages from the paratype follows. Immature female, 12.8 mm. Pereon length almost 3x pleon, slightly inflated, mainly due to enlarged pereonites 1–4. Head with short, hook-shaped rostrum. Eyes small. Antennae 1 almost as long as head and first two pereonites combined. Antennae 2 shorter than A1 and shorter than mandibular palp; length about 0.6x A1. Gnathopod 1; basis slightly shorter than remaining articles combined; dactylus curved, length 0.2x propodus. Gnathopod 2; length 1.4x G1; basis slightly shorter than remaining articles combined; dactylus relatively straight, length 0.2x propodus. Pereopods 3 & 4 similar in structure with P4 slightly longer than P3; basis length about twice merus; carpus slightly expanded with several moderate setae on distal margin, length 1.7x merus; propodus relatively narrow, slightly longer than carpus; dactylus slightly curved, length less than 0.2x but more than 0.1x propodus. Pereopod 5 subequal in length to P4; basis length about twice merus; carpus slightly expanded with several moderate setae on anterior margin, length 1.5x merus; propodus relative narrow, marginally longer than carpus with tuft of relatively strong setae on anterodistal corner; dactylus curved slightly, length less than 0.2x but more than 0.1x propodus. Pereopod 6 marginally longer than P5; basis length almost twice merus; carpus slightly expanded with several moderate setae on anterior margin, length 1.4x merus; propodus relatively narrow, length 1.3x carpus; dactylus curved slightly, length less than 0.2x but more than 0.1x propodus. Pereopod 7; length about 0.6x P6; basis length slightly more than twice merus; carpus length 1.4x merus; propodus length 1.3x carpus; dactylus curved, length less than 0.2x but more than 0.1x propodus. Uropoda with relatively slender peduncles and rami. Peduncle of U1 slightly exceeds limit of peduncle of U2. Telson rounded; width at base about 0.7x length, slightly shorter than half of peduncle of U3.

Colour of living specimen not known.

Description of paratype. Damaged immature female, approximately 15.0 mm, similar to holotype. Antennae 1 with elongate callynophore, length about 3x peduncle; terminal article slender, slightly longer than preceding two articles combined. Antennae 2 with terminal articles missing, length about 0.7x A1. Mandibles with relatively broad incisor; body rectangular in shape; left with lacinia mobilis reduced to small protuberance; palp length about 1.8x length of body, length third article 0.7x second. Maxillae 1; palp slightly longer than outer lobe, with feathered seta on outer distal corner, inner margin denticulate; outer lobe armed with five robust setae terminally and a covering of slender setae; inner lobe rounded with covering of slender setae. Maxillae 2 with relatively narrow lobes, the inner armed with eight and the outer with seven, slender strong setae distally. Maxillae with semi-circular outer lobes; inner lobes very short, fused proximally, projecting laterally from outer lobes.

Etymology. This species is named to honour the Carlsberg Foundation that sponsored the Dana Expeditions and many other scientific endeavours, and continues to support scientific research. Grants from the Carlsberg Foundation enabled me to study the collections at the ZMUC during July 2002, September 2003, and July/ August 2007.

Remarks. This species is most similar to M. diomedeae as described and figured by Woltereck (1909) and Vinogradov (1964), particularly in regard to the relatively short dactyls of the pereopods and the slightly expanded carpus of pereopods 5 & 6. However, as mentioned earlier, Woltereck’s species is practically unrecognisable and there is some uncertainty regarding the true identity of Vinogradov’s (1964) specimens, described as representing M. diomedeae . The current species differs from M. diomedeae primarily in that the second antennae are clearly shorter than the first, and shorter than the mandibular palp, and pereopods 4–6 are of similar length. Mimonecteola mixta also has second antennae that are slightly shorter than the first and, in females, the propodus of pereopod 5 is armed with a tuft of relatively strong setae on the posterodistal corner as in M. carlsbergi , but it is readily distinguished by the partly retractile, and partly hooked dactylus, of pereopod 7.

Both type specimens are immature, judging by the very small, poorly developed oostegites. Distribution. Only known from the two types, from off South Africa in the South Atlantic and the Southwest Indian Ocean as detailed above .