Liljeborgia ossiani, d & d & Acoz & Vader, 2009

d, Cédric, d, Udekem, Acoz & Vader, Wim, 2009, On Liljeborgia fissicornis (M. Sars, 1858) and three related new species from Scandinavia, with a hypothesis on the origin of the group fissicornis, Journal of Natural History 43 (33 - 34), pp. 2087-2139 : 2120-2131

Liljeborgia ossiani sp. nov.

( Figures 20–26 )

Lilljeborgia fissicornis ; Boeck, 1876, p. 499, pl. 18, fig. 10 (in part); G.O. Sars, 1890 –1895, p. 534, pl. 189; Chevreux and Fage, 1925, p. 156 –157, fig. 156 (after G.O. Sars, 1890 –1895); Stephensen, 1929, p. 111, fig. 27.168 (after G.O. Sars, 1890 –1895); Stephensen, 1931, p. 221 –223 (in part); Stephensen, 1938, p. 196 –197 (in part); Gurjanova, 1951, p. 316 (in part), fig. 316 (after G.O. Sars, 1890 –1895).

Liljeborgia fissicornis ; Stebbing, 1906, p. 230 –232 (in part).

Material examined

County of Troms, Tromsø, Skatøra , 25–30 fathoms, 08 September 1887: about 30 specimens (female holotype + paratypes), leg. H.J. Sparre-Schneider, TSZCr 1188; west of the county of Finnmark, R / V Johan Ruud, sta. 301–05, 71°00.29′ N, 025°21.59′ E, 155 m, sand with hydroids, RP sledge, 13 April 2005: about 15 paratypes (2 vials), leg. C. d’Udekem d’Acoz, TSZCr 13999; county of Troms, Vestfjorden, East of Skrova , R / V Johan Ruud , sta. 722–02, 68°07.08′ N, 014°54.32′ E, 328 m, sledge, 26 September 2002: 2 paratypes, leg. W. Vader and C. d’Udekem d’Acoz, RBINS I.G. 31183; county of Troms, Vestfjorden, East of Molla , R / V Johan Ruud , sta. 724–02, 68°11.27′ N, 014°59.87′ E, 446 m, sledge, 26 October 2002: 2 paratypes of which one is an ovigerous female, leg. W. Vader and C. d’Udekem d’Acoz, RBINS I.G. 31183.

Description

Rostrum well developed, very narrow, with acute tip. Eye absent.

A1. Major flagellum with 18 in female; accessory flagellum with 11 articles.

A2. Fourth article of peduncle with short slender ventrolateral and dorsomedial spines; fifth article with ventrolateral spines; flagellum with 14 articles.

Epistome. Rounded, barely protruding in lateral view.

Md. Left lacinia mobilis large with anterior margin with five rounded teeth; right lacinia mobilis significantly smaller than left one, with anterior margin slightly denticulate and with one large lateral triangular tooth; spines of incisor process not bifid but some are weakly denticulate, distal one rather stout; article one of palp shorter than article two (ratio length article one: article two = 0.81); article one 5.00 times as long as wide; article two with setae on tip only, 6.17 times as long as wide; article three 3.96 times as long as wide, 0.54 times as long as article two.

Mx1. First article of palp without setae; second article of palp with three strong and long setae (not forming transverse rows) on upper margin, eight slender spines on ventral and apical margins and five facial setae; outer plate with 10 spines of normal stoutness, of which some are strongly denticulate; inner plate with a single seta on tip.

Mx2. Outer plate with four medium-sized setae on upper margin.

Mxp. Palp with dactylus fairly stout, with ventral margin distinctly convex, 0.71 times as long as article three; article three of palp with two transverse rows of thin dorsomedial setae; outer plate with 11 normally-spaced spines on medial border (these spines are rather short and rather stout), and about four strong medioventral setae; inner plates with four well-developed anterior spines and eight marginal and submarginal strong setae.

Gn1. Coxa narrowly triangular, with distinctly concave posterior border, with small posterior tooth and tiny anterior tooth; merus and carpus with confluent groups of setae; merus with one small acute distal tooth; tip of carpus almost reaching propodal group of strong spines (as seen in outer view); propodus 1.91 times as long as wide; group of spines on the proximal third of propodus (emergence of most distal spine on outer side used as reference point); one of these spines is rather long; palm border forming a regular curve, without teeth, with hooked spines of outer row narrowly spaced (about 49 hooked outer spines); dactylus with six to seven teeth.

Gn2. Coxa quadrato-elliptic with small anterior and posterior teeth; merus and carpus with confluent groups of setae; carpus with one small acute distal tooth; tip of carpus not reaching propodal group of strong spines; propodus 2.01 (female) or 1.97 (male) times as long as wide; group of spines on the proximal 0.28 (female) or 0.24 (male) of propodus (emergence of most distal spine on outer side used as reference point); these spines are well developed in female but short in male: they arise from a low protrusion in female, from a mere angular discontinuity in male; palm border curved and convex in female but absolutely straight on the largest part of its length in male (except for the distal part, which forms a large obtuse protrusion); palm without teeth in female, with vague crenulations on tip of distal protrusion in male; palm with short medial setae, with hooked spines on outer row in females; these spines are widely spaced (40 hooked spines and seven outer setae in female); dactylus of normal width, with 10 teeth spread on proximal 0.65 in female; with an odd disposition in male: the usual sigmoid teeth are absent, there are a few proximal crenulations and denticules which are followed with a low protrusion and the rest of the dactylus is smooth.

P3. Coxa anteriorly rounded and posteriorly straight, very narrow, with small anterior and posterior teeth; merus 1.36 times as long as carpus and 0.89 times as long as propodus; carpus 5.75 to 5.85 times as long as wide; propodus 10.00 to 10.52 times as long as wide; dactylus not very long, slender with its two borders slightly curved, 0.63 times as long as carpus and 0.41 to 0.44 times as long as propodus; posterior border of merus with two isolated short setae; carpus with three or four isolated well-developed setiform spines on posterior border (longest spine in distal group; this spine is 0.86 to 1.30 times as long as width of carpus and 0.11 to 0.21 times as long as carpus length), and with a setule at the tip of anterior bor- der; propodus with five to six long setiform spines on posterior border, of which the distal one is paired with a much smaller spine; other setiform spines isolated or sometimes paired with a tiny setule (longest setiform spines 0.92 to 1.06 times as long as width of propodus and 0.092 to 0.10 times as long as length of propodus); anterior border of propodus with poorly-developed distal group of zero to two spiniform setae.

P4. Coxa rather narrow (1.37 times as long as wide), with anterior and posterior bor- der nearly parallel (slightly diverging downwards), with ventral border weakly convex, with three well-developed teeth on posterior border and one normally developed anteroventral tooth; merus 1.48 times as long as carpus and 0.92 times as long as propodus; carpus 5.52 times as long as wide; propodus 11.63 times as long as wide; dactylus not very long, rather slender with its two borders slightly curved, 0.63 times as long as carpus and 0.41 times as long as propodus; posterior border of merus without setae; carpus with three isolated well-developed setiform spines on posterior border (longest spine in distal group; this spine is 0.97 times as long as width of carpus and 0.17 times as long as carpus length), and with a tiny setule at the tip of anterior bor- der; propodus with six long isolated setiform spines on posterior border, of which the distal one is paired with a much smaller spine (longest setiform spines 1.21 times as long as width of propodus and 0.10 times as long as length of propodus); anterior border of propodus with poorly-developed distal group of zero to two spiniform setae.

P5. Basis very narrow (2.13 to 2.23 times as long as wide), anteriorly distinctly and regularly convex, posteriorly almost straight (very weakly convex); anterior border with conical spines, posterior border with nine distinct but not especially strong, nonerect teeth, tip of distal tooth almost reaching posterodistal angle, distal border slightly convex in its posterior half (junction between posterior and distal borders forming a curve) and produced into a very low lobe; merus with anterior group and posterior groups of very short spines; carpus with three anterior groups of small slen- der spines and one posterior spine (in addition to apical group); carpus 0.61 times as long as merus; propodus with some spines and setae; propodal apical tuft of setae well developed; dactylus distinctly curved and fairly stout, with small subdistal notch, about 0.22 times as long as propodus.

P6. Basis very narrow (2.29 to 2.35 times as long as wide), anteriorly slightly convex and posteriorly straight; anterior border with conical spines, posterior border with eight to 10 distinct but not especially strong, non-erect teeth, tip of distal tooth almost reaching posterodistal angle, distal border slightly convex in its posterior half (junction between posterior and distal borders forming a curve) and produced into a very low lobe; merus with anterior groups of long slender spines and posterior groups of small spines; carpus with anterior and posterior groups of well-developed spines; carpus 0.65 to 0.70 times as long as merus; propodus with four to six anterior spines (often rubbed off but usually leaving insertion scars) followed by a tuft of moderately long setae (also often rubbed off); dactylus almost straight and fairly stout, 0.18 to 0.27 times as long as propodus.

P7. Upper part of posterior border of coxa not produced into a tooth; basis proximally expanded, very narrow (1.70 to 1.84 times as long as wide), anteriorly slightly but distinctly convex and posteriorly almost straight (slightly concave); anterior bor- der with conical spines, posterior border with nine to 10 distinct teeth, tip of distal tooth almost reaching posterodistal angle, distal border slightly convex in its posterior half (junction between posterior and distal borders forming an abrupt curve) and produced into a very low lobe; merus and carpus with long anterior and posterior spines; carpus 0.96 to 1.00 times as long as merus; propodus of P7 2.04 times as long as propodus of P6, propodus with eight anterior groups of one or two long spines and four to six posterior groups of one or two long spines which may be associated with a long and slender seta; propodal apical tuft of setae present (but easily rubbed off); dactylus nearly straight, distally not notched, fairly stout, short, 0.18 to 0.20 times as long as propodus.

Pleonite 1. Posterodorsal area produced into one large tooth; Ep1 with small posteroventral tooth, with posterior border distinctly convex; without setae.

Pleonite 2. Posterodorsal area produced into one large tooth; Ep2 with small posteroventral tooth, with posterior border slightly convex.

Pleonite 3. Posterodorsal area produced into a small but very distinct tooth; Ep3 with small posteroventral tooth (of which the ventral margin is regularly and strongly convex), with posterior border almost straight (very weakly convex) on all its length and joining the posteroventral tooth after forming a shallow notch.

Urosomite 1. With crest-like carina, posteriorly terminated into a strong posterodorsal tooth obliquely pointing upwards; ventrolateral border with one spine; peduncle of U1 with nine dorsolateral spines: eight regularly-spaced short slender ones spread on all length of peduncle and a long and strong distal one, with five dorsomedial spines (which are stout and short except the distal one which is medium-sized) regularly spaced all along its length; outer ramus with six well-developed outer spines and four short medial spines; inner ramus with five short spines on outer border and seven well-developed spines on medial border.

Urosomite 2. With dorsal border forming a large triangular tooth pointing obliquely upwards; peduncle of U2 with four or five regularly-spaced and fairly long (the distal one is long) slender dorsolateral spines, with two or three dorsomedial spines; outer ramus with five short large spines and one short medial spine; inner ramus with four short spines on outer border and six large and stout spines on medial border.

Urosomite 3. With a pair of very long posterodorsal styliform spines; lateral projection usually produced into a tooth; outer ramus of U3 with one or two groups of one or two long spines; inner ramus with three long and stout spines on outer border, with four long and stout spines on medial border.

Telson. Cleft on 0.58 of its length; medial tooth of each lobe reaching 0.28 to 0.44 of outer tooth; inter-teeth spine very long, overreaching tip of outer tooth by 0.63 of its length, 0.46 times as long as telson; apical teeth of telson without setae.

Colour pattern

Uniformly yellowish, extremities of legs almost colourless; eggs white, transparent, with orange embryos, or clear orange-yellow. No difference of pigmentation at the place where eyes would have been expected (observations by the second author).

Size

Up to 10 mm.

Depth range

55 to 446 m (present material).

Distribution

Northern Norway (present material). The data of G.O. Sars (1890 –1895) suggest the species occurs all along the coasts of Norway. The map of Stephensen (1931) suggests the occurrence of coastal Liljeborgia group fissicornis with a posterodorsal tooth on the third pleonite (hence probably L. ossiani ) on the continental shelf of Svalbard. However, it is not very clear whether he actually saw specimens. Therefore, the occurrence of L. ossiani in Svalbard waters needs confirmation.

Etymology

The species is dedicated to the famous Norwegian naturalist Georg Ossian Sars, who was the first to provide good illustrations of the species, albeit under the erroneous name L. fissicornis (M. Sars, 1858) . The name ossiani is the genitive of his middle name (the name he used in everyday life), which is here latinized in ossianus.

Remarks

Lilljeborgia ossiani sp. nov. is found in the same depth range (less than 500 m) as L. fissicornis and the two species are even sometimes found at the same station. However, the maximum size of the two species is markedly different: 10 mm for L. ossiani sp. nov. and 24 mm for L. fissicornis .

The identity of the L. fissicornis of Norman (1889, p. 117–118, Pl. 10, fig. 11) is not clear, but it is perhaps L. ossiani sp. nov. because the distal articles of pereiopod 7 illustrated by this author look very slender.

Figures

Figure 20. Liljeborgia ossiani sp. nov., female, holotype, Tromsø, Skatøra, TSZCr 1188. (A) Head and antennae; (B) anterior part of head with epistome and mandible; (C) right Md; (D) distal part of right Md; (E) distal part of left Md; (F) left Mx1; (G) right Mx1.

Figure 21. Liljeborgia ossiani sp. nov., female, holotype, Tromsø, Skatøra, TSZCr 1188. (A) Mxp; (B) right outer plate of Mxp; (C) left inner plate of Mxp; (D) distal part of left inner plate (only insertion of setae indicated).

Figure 22. Liljeborgia ossiani sp. nov., Tromsø, Skatøra, TSZCr 1188; A–D, female, holotype, E, F, male, paratype. (A) Left coxa 1; (B) left Gn1; (C) left coxa 2; (D) left Gn2; (E) left Gn1; (F) left Gn2.

Figure 23. Liljeborgia ossiani sp. nov., female, holotype, Tromsø, Skatøra, TSZCr 1188. (A) Left P3; (B) articles 5–7 of left P3; (C) left P4; (D) articles 5–7 of left P4.

Figure 24. Liljeborgia ossiani sp. nov., Tromsø, Skatøra, TSZCr 1188; A–F, I, female, holotype, G, female, paratype; H, sex unknown (detached appendage), paratype. (A) Left P5; (B) distal part of basis of left P5; (C) left P6; (D) distal part of basis of left P6; (E) left P7; (F) distal part of basis of left P7; (G) right P6; (H) articles 5–7 of left P7 (medial view); (I) telson.

Figure 25. Liljeborgia ossiani sp. nov., female, holotype, Tromsø, Skatøra, TSZCr 1188. (A) Pleon in lateral view; (B) right U1; (C) right U2; (D) peduncle of left U2; (E) right U3; (F) outer ramus of right U3.

Figure 26. Liljeborgia ossiani sp. nov., female, paratype, Finnmark, R/V Johan Ruud sta. 301–05, TSCZCr 13999. (A) Articles 5–7 of left P3; (B) left P5; (C) articles 6 and 7 of left P5; (D) left P6; (E) articles 6 and 7 of left P6; (F) left P7; (G) articles 6 and 7 of left P7.