Lissosabinea armata, Komai, 2006

Komai, Tomoyuki, 2006, A review of the crangonid genus Lissosabinea Christoffersen, 1988 (Crustacea, Decapoda, Caridea), with descriptions of three new species from the western Pacific, Zoosystema 28 (1), pp. 31-59 : 44-49

Lissosabinea armata n. sp.

( Figs 7-9 )

HOLOTYPE. — New Caledonia, BATHUS 3, stn DW 776, 24°44.24’S, 170°08.01’E, 770-830 m, 24.XI.1993, ♀ cl 6.6 mm (MNHN-Na 15156).

PARATYPE. — Same data as holotype, 1 badly damaged female cephalothorax cl 7.5 mm (MNHN-Na 15157).

DISTRIBUTION. — Known only from southern New Caledonia; at depths of 770-830 m.

SIZE. — Non-ovigerous, but spawning female cl 6.6- 7.5 mm.

ETYMOLOGY. — From the Latin armatus (= armed), in reference to the strong armature on the carapace.

DESCRIPTION

Rostrum ( Fig. 8A, B ) straight, directed forward, relatively broad, slightly overreaching distal margin of first segment of antennular peduncle; distal part spiniform, lacking ventral blade; dorsal surface with low, blunt median ridge and shallow sulcus on either side of median ridge extending to level of base of epigastric tooth, and with few setae; dorsolateral margin slightly elevated, armed with large tooth arising from midlength of rostrum and reaching anterior 0.30 of rostrum; lateral face excavate at base, with sharp lateral carina extending to tip of rostrum.

Carapace ( Figs 7 ; 8A, B ) 1.50 times as long as wide. Middorsal carina sharp, extending nearly to posterodorsal margin of carapace, armed with three large teeth; epigastric tooth overreaching base of rostrum, arising at 0.11 of carapace length; second tooth slightly smaller than first, arising from 0.33 of carapace length; third (= cardiac) tooth smallest, arising at 0.61 of carapace length. Dorsal surface of carapace with two pairs of long plumose setae at level of midlength (either side of second median tooth). Antennal tooth long, slightly ascending,

Komai T.

reaching anterior margin of cornea of eye. Branchiostegal tooth directed somewhat dorsally, overreaching anterior margin of antennal basicerite. Pterygostomian angle with tiny tooth. Lateral face of carapace with relatively large hepatic and epibranchial teeth; epibranchial carina relatively long, conspicuous.

Sternal tooth on fifth thoracic somite ( Fig. 8C ) well developed even in spawning female, extending beyond base of spur on fourth somite.

Second abdominal somite ( Fig. 7 ) smooth on dorsal surface. Third somite ( Figs 7 ; 8D ) with very high, thick middorsal carina in posterior 0.75, very strongly arched in lateral view; posterodorsal margin of somite strongly produced posteriorly, partially covering fourth somite. Sixth somite about 2 times as long as high; dorsal surface flat on midline. Telson ( Fig. 8E, F ) with two pairs of small, blunt dorsolateral spines; posterolateral angle with three spines, lateralmost spine short, blunt, second spine slender, third, mesialmost spine stout, longest; terminal process rounded.

Cornea of eye ( Fig. 8A, B ) spherical, lightly pigmented with opaque, maximum diameter 0.16 of carapace length.

Antennular peduncle ( Fig. 8A, B ) reaching 0.35 of antennal scale; stylocerite elongate, reaching nearly distal margin of third segment, spiniform; lateral flagellum composed of eight or nine articles in female; mesial flagellum composed of nine or 10 articles in female. Antennal scale ( Fig. 8A ) about 0.64 of carapace length and 2.10 times as long as wide, lateral margin straight, distal blade truncate; basicerite with long ventrolateral spine reaching level of distal margin of first segment of antennular peduncle; carpocerite reaching 0.35 of antennal scale.

Third maxilliped ( Fig. 9A ) reaching distal margin of antennal scale by tip of ultimate segment; ultimate segment longer than carpus (= penultimate segment); antepenultimate segment moderately slender, not foliaceus.

First pereopod ( Fig. 9B, C ) with palm about three times as long as wide; cutting edge of palm weakly oblique; pollex relatively long, slender, not recurved; carpus armed with two moderately large spines on lateral margin; merus with very strong dorsodistal spine overreaching distal margin of anteriorly extended carpus, distolateral margin with tiny blunt tooth; ventral lamina terminating distally in small acute tooth. Second pereopod ( Fig. 9D ) not reaching midlength of merus of first pereopod; dactylus about 0.25 length of propodus; propodus weakly widened distally. Third pereopod ( Fig. 9E ) slender; ischium 1.76 times as long as merus. Fourth pereopod ( Fig. 9F ) stout, not reaching antennal scale; dactylus ( Fig. 9G ) strongly compressed laterally, about 0.29 times as long as propodus, terminating in acute unguis; dorsal margin of dactylus somewhat laminate, convex in lateral view; propodus notably tapering distally, lacking distal tuft of setae, with large articulating knobs against dactylus; carpus 0.56 times as long as propodus; merus about three times as long as wide, unarmed on dorsodistal margin; ischium 0.74 times as long as merus. Fifth pereopod ( Fig. 9H ) similar to fourth, not reaching midlength of antennal scale.

Coloration

Unknown. REMARKS

As mentioned before, the presence of three median teeth on the carapace links this new species to L. tridentata . However, L. armata n. sp. differs from its congeners in many characters, making it unique within the genus:the median teeth on the carapace are larger than in any other congeneric species, particularly the first tooth overhanging the base of the rostrum; the antennal tooth on the carapace is elongate, slightly overreaching the anterior margin of the eye; the third abdominal somite is provided with an unusually high,

Review of Lissosabinea ( Crustacea, Decapoda , Crangonidae )

broad median carina; the posteromedian process of the telson is rounded; the antennular stylocerite is elongate, reaching the distal margin of the third segment of the antennular peduncle; the ventrolateral tooth on the antennal basicerite is elongate, reaching the level of the distal margin of the first segment of antennular peduncle; the cutting edge of the subchela is less oblique than in other congeners; the propodi of the second pereopod are somewhat broadened distally; the fourth and fifth pereopods are very stout, with short, laterally compressed dactyli and propodi notably tapering distally; the distal tufts of setae on the propodi of the fourth and fifth pereopods are rudimentary. Other characters differentiating between L. armata n. sp. and L. tridentata include: the epibranchial carina on the carapace is more clearly defined in L. armata n. sp. than in L. tridentata ; the distal margin of the blade of the antennal scale is obliquely truncate in L. armata n. sp., rather than broadly rounded in L. tridentata .

Figures

FIG. 7. — Lissosabinea armata n. sp., entire animal in lateral view, New Caledonia, BATHUS 3, stn DW 776, holotype ♀ cl 6.6 mm (MNHN-Na 15156). Scale bar: 2 mm.

FIG. 8. — Lissosabinea armata n. sp., New Caledonia, BATHUS 3, stn DW 776, holotype ♀ cl 6.6 mm (MNHN-Na 15156): A, carapace and cephalic appendages, dorsal view (tegumental scales omitted); B, anterior part of carapace and cephalic appendages, lateral view; C, thoracic sternum, ventral view; D, third to sixth abdominal somites, dorsal view; E, telson, dorsal view; F, posterior part of telson, dorsal view. Scale bars: A, D, 2 mm; B, C, E, 1 mm; F, 0.5 mm.

FIG. 9. — Lissosabinea armata n. sp.: A-C, New Caledonia, BATHUS 3, stn DW 776, paratype badly damaged female cephalothorax cl 7.5 mm (MNHN-Na 15157); A, third maxilliped, dorsal view; B, left first pereopod, lateral view; C, same, chela, dorsal view; D-H, same station, holotype ♀ cl 6.6 mm (MNHN-Na 15156); D, second pereopod, lateral view; E, left third pereopod, lateral view; F, left fourth pereopod, lateral view; G, same, dactylus and distal part of propodus, lateral view; H, left fifth pereopod, lateral view. Scale bars: A-C, E, F, H, 1 mm; D, G, 0.5 mm.