Lissosabinea unispinosa, 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 : 53-56

Lissosabinea unispinosa n. sp.

( Figs 13-16 )

HOLOTYPE. — MUSORSTOM 4, stn 195, 18°54.8’S, 163°22.2’E, 465 m, 19.IX.1985, ovigerous ♀ cl 4.5 mm (MNHN-Na 15161).

PARATYPES. — New Caledonia. MUSORSTOM 4, stn DW 162, 18°35.0’S, 163°10.3’E, 525 m, 16.IX.1985, 1 ovigerous ♀ cl 4.8 mm (MNHN-Na 15162). — Stn CP 170, 18°57.0’S, 163°12.6’E, 480 m, 17.IX.1985, 1 ovigerous ♀ cl 4.6 mm (MNHN-Na 15163). — Stn CP 180, 18°56.8’S, 163°17.7’E, 440 m, 18.IX.1985, 1 ♂ cl 4.3 mm (MNHN-Na 15164). — Stn 195, 18°54.8’S, 163°22.2’E, 465 m, 19.IX.1985, 2 ovigerous ♀♀ cl 4.6, 5.0 mm, 1 cephalothorax cl 5.1 mm (sex could not be determined) (MNHN-Na 15165). — Stn DW 196, 18°55.0’S, 163°23.7’E, 450 m, 20.IX.1985, 1 ovigerous ♀ cl 4.4 mm (MNHN-Na 15166). — Stn DW 222, 22°57.6’S, 167°33.0’E, 410-440 m, 30.IX.1985, 1 ovigerous ♀ cl 4.1 mm (MNHN-Na 15167).

BIOCAL, stn DW 44, 22°47’S, 167°14’E, 440-450 m, 30.VIII.1985, 1 ♀ cl 5.0 mm (MNHN-Na 15168). — Stn CP 45, 22°47’S, 167°15’E, 430-465 m, 30.VIII.1985, 1 ♂ cl 4.1 mm, 2 ovigerous ♀♀ cl 4.3, 4.5 mm (CBM- ZC 8341). — Stn CP 78, 22°16’S, 167°15’E, 445- 450 m, 5.IX.1985, 1 ♀ cl 4.3 mm, 2 ovigerous ♀♀ cl 4.7 mm, crushed (MNHN-Na 15169). — Stn DW 81, 20°29’S, 166°47’E, 430-470 m, 5.IX.1985, 1 ♀ cl 2.9 mm (MNHN-Na 15170).

MUSORSTOM 5, stn DW 301, 22°06.90’S, 159°24.60’E, 487-610 m, 12.X.1986, 1 ♂ cl 3.8 mm, 1 ♀ cl 4.0 mm (MNHN-Na 15171). — Stn DW 305, 22°09.27’S, 159°24.42’E, 430-440 m, 12.X.1986, 1 ovigerous ♀ cl 4.0 mm (MNHN-Na 15172).

MUSORSTOM 6, stn DW 478, 21°08.96’S, 167°54.28’E, 400 m, 22.II.1989, 1 ovigerous ♀ cl 3.7 mm (MNHN- Na 15173).

BATHUS 4, stn DW 929, 18°51.55’S, 163°23.27’E, 502-516 m, 7.VIII.1994, 1 ♂ cl 3.8 mm (MNHN-Na 15174).

Tonga. BORDAU 2, stn CP 1527, Eua, 21°16’S, 174°59’W, 483-509 m, 3.VI.2000, 1 ovigerous ♀ cl 4.5 mm (MNHN-Na 15175).

DISTRIBUTION. — So far known only from New Caledonia and Tonga, 410- 610 m.

SIZE. — Females cl 3.7-5.0 mm, ovigerous females cl 3.7-5.0 mm; males cl 3.8-4.3 mm.

ETYMOLOGY. — From the Latin uni - (one) and spinosa (spined), and indicating the presence of only one median tooth on the carapace.

DESCRIPTION

Rostrum ( Fig. 14A, B ) slightly ascending, straight, narrow, distal part slightly compressed laterally, falling slightly short of or slightly overreaching distal margin of first segment of antennular peduncle; dorsal surface rounded in anterior part and flattened in posterior part, bearing few short setae in proximal 0.40; lateral tooth weak, arising from 0.40-0.50 of rostrum; lateral face slightly concave at base, without lateral carina; ventral margin devoid of blade, but occasionally with one small tooth or trace of tooth subdistally.

Carapace ( Figs 13 ; 14A, B ) 1.10-1.20 times as long as wide. Middorsal carina low, extending to midlength of carapace, terminating anteriorly in small epigastric tooth at anterior 0.10-0.11 of carapace, otherwise unarmed on midline of carapace. Dorsal surface with transverse row of long plumose setae across midlength, interrupted medially. Antennal tooth small, reaching midlength of cornea of eye. Branchiostegal tooth directed forward, falling short of anterior margin of antennal basicerite. Pterygostomial tooth tiny. Lateral surface of carapace with relatively small hepatic tooth, but epibranchial tooth absent; epibranchial carina absent.

Sternal tooth on fifth thoracic somite absent in spawning female ( Fig. 14C ).

Second abdominal somite ( Fig.13 ) dorsally round- ed. Third somite ( Figs 13 ; 14D, E ) with tergum weakly elevated posteriorly, forming broad, rather inconspicuous middorsal carina; posterodorsal margin of somite produced posteriorly. Sixth somite about two times as long as height; dorsal surface rounded.

Komai T.

Telson ( Fig. 14F ) with two pairs of small dorsolateral spines; lateral margin with trace of lobe subproximally; three pairs of spines present on posterolateral corner, of them two mesial pairs very slender, subequal in length; terminal process acutely pointed.

Cornea of eye ( Fig. 14A, B ) very large, somewhat flattened dorsoventrally, maximum diameter 0.30- 0.35 of carapace length.

Antennular peduncle ( Fig. 14A, B ) reaching 0.45- 0.50 of antennal scale; stylocerite reaching distal margin of first segment, slightly compressed laterally; lateral flagellum composed of about eight to 10 articles in females, 20-25 articles in males; mesial flagellum composed of about 11-15 articles in females, 20-25 articles in males. Antennal scale ( Fig. 14A, H ) 0.65-0.70 of carapace length and 3.30-3.50 times longer than wide, lateral margin slightly concave, distal blade slightly rounded; basicerite ( Fig. 14A, B ) with small ventrolateral spine; carpocerite slightly overreaching midlength of antennal scale.

Third maxilliped ( Fig. 16A ) overreaching antennal scale by distal 0.15-0.20 of ultimate segment; ultimate segment slightly longer than carpus (= penultimate segment); antepenultimate segment moderately slender, not foliaceus.

First pereopod ( Fig. 16B, C ) with palm about 3.40-3.50 times longer than wide; cutting edge of palm strongly oblique; pollex relatively large, broadly triangular, slightly recurved; carpus armed with two moderately large spines on distolateral margin; merus with strong dorsodistal spine not reaching distal margin of anteriorly extended carpus, distolateral spine long, slender; ventral carina of merus distinct but not lamelliform, terminating distally in sharp tooth. Second pereopod ( Fig. 16D ) far falling short of midlength of merus of first pereopod; dactylus 0.25-0.30 of propodus length; propodus not widened distally. Third pereopod ( Fig. 16E ) very slender; ischium 2.50-2.60 of merus length. Fourth pereopod ( Fig. 16F ) relatively stout, overreaching antennal scale by length of dactylus; dactylus ( Fig. 16G ) 0.35-0.40 of propodus length, subconical, slightly curved, terminating in acute unguis; propodus with distal tuft of setae ( Fig. 16G ); carpus 0.60-0.70 of propodus length; merus about 8.0-8.5 longer than wide, unarmed on dorsodistal margin; ischium 0.45-0.50 times of merus length. Fifth pereopod ( Fig. 16H ) similar to fourth, reaching antennal scale by tip of dactylus; ischium 0.44-0.47 of merus length.

Endopod of first pleopod of male ( Fig. 14J ) sinuous, spatulate; female endopod ( Fig. 14I ) slender tapering distally. Appendix masculina on second pleopod distinctly longer than appendix internae ( Fig. 14K ), bearing moderately long bristles on dorsal surface to terminal to subterminal parts.

Coloration

Unknown.

REMARKS

This new species is unique within the genus in having only one small middorsal tooth (= epigastric tooth) on the carapace. Other characteristics of L. unispinosa n. sp. include: the eye is somewhat depressed dorsoventrally and its size is very large, maximum diameter is 0.30-0.35 of the carapace length; the subchela has a strongly oblique cutting edge and relatively large, recurved pollex; and the dactyli of the fourth and fifth pereopods are subconical, neither dorsoventrally nor laterally compressed. In comparison with L. ecarina n. sp., L. indica and L. tridentata , the fourth and fifth pereopods are relatively stout, but being less stout than in L. armata n. sp.

Figures

FIG. 13. — Lissosabinea unispinosa n. sp., entire animal, lateral view, New Caledonia, MUSORSTOM 4, stn 195, holotype ♀ cl 4.5 mm (MNHN-Na 15161). Scale bar: 2 mm.

FIG. 14. — Lissosabinea unispinosa n. sp.: A-I, New Caledonia, MUSORSTOM 4, stn 195, holotype ♀ cl 4.5 mm (MNHN-Na 15161);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 abdominal somite, dorsal view; E, fourth to sixth abdominal somites, dorsal view; F, telson, dorsal view; G, posterior part of telson, dorsal view; H, right antennal scale, dorsal view; I, left first pleopod, ventral view; J, K, New Caledonia, BIOCAL, stn CP 45, paratype ♂ cl 4.1 mm (CBM-ZC 8431); J, left first pleopod, ventral view; K, appendix interna and masculina, ventromesial view. Scale bars: A, B, D-F, H, I, 1 mm; C, G, J, 0.5 mm; K, 0.25 mm.

FIG. 15. — Lissosabinea unispinosa n. sp., left mouthparts, New Caledonia, BIOCAL, stn CP 45, paratype ovigerous ♀ cl 4.3 mm (CBM-ZC 8341): A, mandible, ventral view, inset, distal part, inner view; B, maxillule; C, maxilla; D, first maxilliped; E, second maxil- liped. Scale bar: 0.5 mm.

FIG. 16. — Lissosabinea unispinosa n. sp., left appendages,New Caledonia,MUSORSTOM 4, stn 195,holotype ovigerous ♀ cl 4.5 mm (MNHN-Na 15161): A, third maxilliped, dorsal view; B, first pereopod, lateral view; C, same, chela, dorsal view; D, second pereopod, lateral view; E, third pereopod, lateral view; F, fourth pereopod, lateral view; G, same, dactylus and distal part of propodus, lateral view; H, fifth pereopod, lateral view. Scale bars: A-C, E, F, H, 1 mm; D, G, 0.5 mm.