Leucothoe merletta, Krapp-Schickel & Broyer, 2014

Krapp-Schickel, Traudl & Broyer, Claude De, 2014, Revision of Leucothoe (Amphipoda, Crustacea) from the Southern Ocean: a cosmopolitanism concept is vanishing, European Journal of Taxonomy 80, pp. 1-55 : 27-30

Leucothoe merletta sp. nov.

urn:lsid:zoobank.org:act:6C2BCD72-777F-4825-B595-A23EBFE445C9

Figs 5 , 13-14

Diagnosis

Eyes round, yellowish. Mandibular palp art. 3 nearly as long as art. 2. Cx 2 smooth, in shape of a parallelogram, anterodistal corner acutely lengthened. Cx 4 also with anteridistal corner acutely lengthened, but posterior margin much shorter than anterior one. Gn 1 propodus l:w = 4, dactylus reaching nearly 1/2 of propodus length. P 5-7 basis oval, with regularly rounded hind margin, ratio l:w about 1.5; posterior margin in P 7 smooth. Ep 2 distoposterior corner slightly upturned, Ep 3 posterodistally with rectangular corner. T l:w not known.

Etymology

In Italian “merletto” is the bobbin lace; as the very acutely elongated Cx 2 and Cx 4 can remind on lacecollars, this epitheton (Latinized flexible adjective) was coined.

Type material

Holotype ♀ 2.5 mm, Belgian-Dutch Antarctic Expeditions ( RBINS, I.G. 23694 / INV. 103463); EABN 1966-67: sta. 238; 3 Feb. 1967; Breid Bay, Baie Léopold; 70°19’S, 24°14’E; 200 m; bottom trawl; coll. M. Steyaert & M. Meisch.

Description

Length 2.5 mm.

Head

Anterior margin rounded, anterodistal margin rectangular with rounded corner. Mid-cephalic keel not prominent. Rostrum small.

Eyes round, yellow.

Antennae short and robust, A 1 flagellum 5-articulate, peduncle art. 1 subequal in length but twice the width of article 2, disto-inferiorly without acute tooth, art. 3 nearly 1/2 of art. 2, acc. flagellum not seen. Peduncle art. 3 + flagellum about as long as peduncle art. 2.

A 2 subequal in length with antenna 1, peduncle art. 4> art. 5, flagellum 4 arts.

Mouthparts: Mandibles lacking molars, incisor and lacinia mobilis dentate; palp 3-articulate, art. 2 with 4 long lateral and one distal setae, art. 3 with 2 distal setae, subequal to art. 2.

Peraeon

Cx 1 smooth, length> width; anterior margin smooth, anterodistal corner somewhat lengthened, facial setae absent, inferior margin smooth.

Gn 1 basis somewhat inflated, smooth; ischium smooth; carpus basis more than half as long as propodus, distal part linear, narrow, about 7-9 x longer than wide (width very different); propodus straight, about 5 x as long as wide, palm smooth; dactylus smooth, reaching more than 1/3 propodus length.

Cx 2 about as wide as long, in the shape of a parallelogram, width similar to Cx 3, distally smooth; anterior margin scarcely excavate, anterodistal corner acutely lengthened, inferior and posterior margin straight, facial setae absent.

Gn 2 basis not inflated, on anterior margin some setae; carpus nearly reaching half propodus length, curved, distally rounded, with small incision, setose; propodus anterodistally without prolongation, with some setae, posterior margin with many low humps, palm convex, proximally near dactylus-end with weak blunt corner; facial setae medially and submedially present, but not abundant; dactylus curved, both margins smooth, bare, reaching somewhat more than half of propodus length.

Cx 3 length subequal to width, rounded, anterior and posterior margin straight, quadrangular, smooth, facial setae absent.

Cx 4 length shorter then width, smooth, bare, anterior margin distally excavate, anterodistal corner acutely pointed and lengthened, posterior margin clearly shorter than anterior one, rounded, facial setae absent.

P 3, 4 basis slender, width subequal to merus; dactylus reaching nearly half length of propodus, posterior margins smooth.

Cx 5-7 facial setae absent.

P 5-7 similar, bases l:w ratio about 1.5, margins smooth. Merus with posterodistal corner scarcely lengthened and not widened.

Pleon

Ep 1-3 bare. Ep 2 posterodistal corner somewhat upturned, rounded; Ep 3 posteroventral corner blunt, rectangular.

Uropods: U 2 with unequal rami, the shorter one shorter than peduncle. U 3 unknown.

Telson ratio l:w unknown.

Remarks

Until now we know only one representative of this new species, but the peculiar shape of Cx 2 and Cx 4 makes it easy to recognize it within the Antarctic and sub-Antarctic species. Within the hitherto known Leucothoe species L. lilljeborgi (Boeck, 1861) as well as L. ayrtonia Bellan-Santini, 1997 have a similar Cx 4 with a pointed anterodistal corner but rounded Cx 2, while L. angusticoxa (Ledoyer, 1972) , described as “ Leucothopsis n. gen. ”, has Cx 2 pointed and Cx 4 rounded.

Distribution

East Antarctic, off Queen Maud Land, Breidbay (70°S, 24°E).

Depth range

200 m.

Figures

Fig. 5. Distribution of Leucothoe antarctica Pfeffer, 1888, L. campbelli sp. nov., L. longimembris sp. nov., L. macquariae sp. nov. and L. merletta sp. nov. The hydrographic fronts shown on the map are from north to south: the Sub-Tropical Front, the Sub-Antarctic Front, the Antarctic Polar Front and the Southern Antarctic Circumpolar Current Front. Mean position of the fronts according to Sokolov & Rintoul (2009). TL = type locality.

Fig. 13. Leucothoe merletta sp. nov., holotype ♀ 2.5 mm: A 1, 2 = antenna 1, 2; Md = mandible; Gn 1 = gnathopod 1; Gn 1’ = gnathood 1 reduced and from other side; Cx 2 = coxa 2.

Fig. 14. Leucothoe merletta sp. nov., holotype ♀ 2.5 mm: Gn 2 = second gnathopod; Gn 2’ = second gnathopod from other side; P 3-7 = peraeopod 3-7; Ep 1-3 = epimeral plate 1-3; U 1, 2 = uropod 1, 2 (uropod 3 lacking); T = telson.