Leucothoe campbelli, 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 : 12-16

Leucothoe campbelli sp. nov.

urn:lsid:zoobank.org:act:21CA5E07-C2F3-4A9E-8412-85C8CBDA07C6

Figs 5-7

sub Leucothoe spinicarpa variant 2 – Holman & Watling 1983: 228, fig, 11a-c.

Diagnosis

Eyes large, round. Mandibular palp long and narrow, art. 3 1/2 length of art. 2. Cx 3 subtrapezoidal, ventrally smooth. Gn 1 propodus l:w = 5, dactylus reaching about 1/3 of propodus length. Gn 2 dactylus much longer than half length of propodus hind margin. P 5-7 basis oval, not much broadened, posterodistal corner lengthened, especially in P 7, ratio l:w = 1.66; Ep 2 posterodistally with rounded upturned corner, posterior margin somewhat excavated near posterodistal corner. Ep 3 with right angled posterodistal corner. T l:w = 3.

Etymology

The latinized adjective indicates the original locality of the new species.

Type material

Holotype ad.? ♂ 6.5 mm, slide (Australian Museum, Sydney P. 80888); Southern Ocean , Campbell Island, Perseverance Harbour, cliff west of Davis Point: sta. CA 271 ; 7 Feb. 1980; 52.6°S, 169.2°E; CA 271 , 23 m depth; encrusting yellow sponge, larger sponges, barnacles and mussels, detritus and fine sediments.

Additional material

Australian Museum, Sydney

P. 80883: Southern Ocean, Campbell Island, Perseverance Harbour, west side of Davis Point; sta. CA 71; 1 Jan. 1980; 52.6°S, 169.2°E; 16 m depth; sponges between boulders, barnacles and bryozoans from rock face: 3 spec. 3, 6 and 7 mm.

P. 80884: Southern Ocean, Campbell Island, Perseverance Harbour, west side of Davis Point; sta. CA 102; 4 Jan. 1980; 52.6°S, 169.2°E; 25 m depth; sponges and tunicates, barnacles and bryozoans from rock face: 8 spec. 4-6 mm, 1 ♀ ov. 7 mm.

P. 80885: Southern Ocean, Campbell Island, Perseverance Harbour, west side of Davis Point; sta. CA 105; 4 Jan. 1980; 52.6°S, 169.2°E; 25 m depth; algae and sponges on mussels attached to boulders: 3 immat. 2.5, 3 and 4 mm.

P. 80886: Southern Ocean, Campbell Island, Smoothwater Bay, cliffs West of East Cape; sta. CA 150; 13 Jan. 1980; 52.5°S, 169.2°E; 18 m depth; holdfasts of Durvillaea antarctica (Chamisso) Hariot , sediment and red algae from rock crevice: 1 immat. 4 mm.

P. 80887: Southern Ocean, Campbell Island, Smoothwater Bay, cliffs west of East Cape; sta. CA 154; 13 Jan. 1980; 52.6°S, 169.2°E; 10 m depth; red algae and hydroids from crevices in rock face: 1 juv. 2.2 mm.

P. 80888: Southern Ocean, Campbell Island, Perseverance Harbour, cliff west of Davis Point; sta. CA 271; 7 Feb. 1980; 52.6°S, 169.2°E; 23 m depth; encrusting yellow sponge, larger sponges, barnacles and mussels, detritus and fine sediments: 6 spec. 5-6 mm.

P. 80889: Southern Ocean, Campbell Island, Perseverance Harbour, cliffs West of Davis Point; Sta. CA 273; 7 Feb. 1980; 52.6°S, 169.2°E; 23 m depth; red algae and sponges from boulders and barnacles: 9 spec. 4-7 mm.

P. 80890: Southern Ocean, Campbell Island, Perseverance Harbour, cliff west of Davis Point; Sta. CA 276; 7 Feb. 1980; 52.6°S, 169.2°E; 23 m depth; sponge with yellow tubes and sediment from boulders: 3 immat. 3-4 mm.

Description

Length

5-7 mm.

Head

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

Eyes large, round.

Antenna 1 one third of body length, flagellum 14-articulate, peduncle art. 1 width proximally less than twice article 2, disto-inferiorly without acute tooth, length art. 1 subequal to art. 2, art. 3 about 1/4 of art. 2, acc. flagellum not seen. Peduncle art. 3 + flagellum about as long as peduncle arts 1+2.

Antenna 2 subequal in length to antenna 1, peduncle art. 4> art. 5, flagellum 7-10 arts.

Mouthparts: Mandibles lacking molars, incisor and lacinia mobilis dentate; palp 3-articulate, art. 2 with 12 long lateral setae, art. 3 with 2 distal setae, art. 2: art. 3 = 2. Maxilliped IP small, ventrally fused, OP reaching about 1/3 of inner margin of palp art. 1; palp articles similar in length.

Peraeon

Cx 1 smooth, length subequal to width; anterior margin smooth, facial setae absent, inferior margin smooth.

Gn 1 basis scarcely inflated, posterior margin with short setae; ischium with one seta; carpus basis more than half as long as propodus, distal part linear and narrow, about 10 x longer than wide; propodus straight, about 5 x as long as wide, palm with 7 short setae; dactylus smooth, reaching about 1/3 propodus length.

Cx 2 wider than long, subrectangular, much wider than Cx 3, distally smooth; anterior margin rounded, anterodistal corner rectangular, inferior margin rounded, posterior one somewhat excavate, facial setae absent.

Gn 2 basis not inflated, both margins setose; carpus reaching about 1/3 propodus length, curved, distally blunt, densely setose; propodus anterodistally with blunt prolongation and one seta, posterior margin in adult male with many low humps, palm convex, proximally near dactylus-end no corner; facial setae medially and submedially present; dactylus curved, both margins smooth, bare, reaching somewhat more than 2/3 of propodus length.

Cx 3 length> width, anterior and posterior margin slightly curved, distally scarcely rounded, smooth, facial setae absent.

Cx 4 length subequal to width or longer than wide, smooth, bare, anterior margin straight, distal margin rounded, posterior margin shorter than anterior one, not excavate, facial setae absent.

P 3, 4 basis very narrow, scarcely wider than merus; dactylus reaching about half length of propodus, posterior margins without spination.

Cx 5-7 facial setae absent. P 5-7 similar, bases length:width ratio = 1.66, anterior margins with very slight serrations and small weak spines, posterior margins smooth or slightly serrate. Merus in P 5-7 with posterodistal corner lengthened, basis in P 7 with characteristically lengthened posterodistal corner.

Pleon

Ep 1-3 posterodistally rounded, Ep 2 with lengthened rounded posteroventral corner and posterior margin slightly emarginate near corner, Ep 3 blunt-rectangular.

Uropods: U 1 rami subequal; U 2 the shortest, with very unequal rami (ratio about 1:2), the shorter one shorter than peduncle; U 3 rami slightly unequal, both shorter than peduncle.

Telson ratio l:w = 3.

No sexual dimorphism known.

Distribution

Campbell Island.

Depth range

10- 25 m.

Habitat

Sponges, hydroids, tunicates, barnacles, bryozoans, holdfasts of Durvillaea antarctica , red algae and sediment.

Remarks

This species has gnathopods similar to the ones of the small specimens of L. weddellensis sp. nov., but the peraeopods are more robust and the posterodistal corners of Ep 2, 3 different; while the here described species lives in shallow depths, L. weddellensis sp. nov. was always found much deeper.

The species has the same ecology as L. macquariae sp. nov., but differs from the latter in Gn 1, 2 propodus, P 7 basis and Ep 3.

Holman & Watling (loc. cit.) described their “variant 2” as following:

“Coxa 3 with smoothly rounded ventral margin, coxa 4 not excavate posteriorly. Gnathopod 1 dactyl 1/4 length and slightly more than 1.5 times as wide as propodus, latter almost 7 times as wide. Third epimeron with quadrate posterodistal corner [...]. The first gnathopod has a considerably shorter dactyl than variant 1 [see L. weddellensis sp. nov. below], but appears similar to Sars’ illustrations fo L. spinicarpa in most other respects. In stations where both variants 1 and 2 occurred, there is also a clear size dichotomy. Large specimens correspond consistently to variant 1, while smaller ones correspond to variant 2 [...]. In addition, several variant 2 females were found to be ovigerous.”

This text stresses how small the morphological differences are, but at the same time confirms the size differences of the ovigerous females.

The ecology, the quite shallow depth range as well as the shape of Gn 2 dactylus and Ep 2, 3 are good indications for this species.

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. 6. Leucothoe campbelli sp. nov., holotype?♂ 6.5 mm. Hd = head; A 1, 2 = antennae 1, 2; Md, Md’ = mandible from both sides; Md" = mandible partly enlarged; Mx 1, 2 = maxilla 1, 2; Mxp = maxilliped; Gn 1, 2 = gnathopod 1, 2.

Fig. 7. Leucothoe campbelli sp. nov., holotype?♂ 6.5 mm. P 3-7 = peraeopod 3-7; P 7’ = peraeopod 7 reduced; Ep 2, 3 = epimeral plates 2, 3; U 1-3 = uropod 1-3; T = telson.