Lissosabinea ecarina, 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 : 49-53

Lissosabinea ecarina n. sp.

( Figs 10-12 )

Sabinea indica – Chace 1984: 59 (in part).

HOLOTYPE. — Indonesia, KARUBAR, stn CP 25, Kai Islands , 05°30’N, 132°52’E, 336-346 m, 26.X.1991, ovigerous ♀ cl 7.7 mm (MNHN-Na 15158).

PARATYPES. — Philippines. Albatross, stn 5550, W of Jolo Island, Sulu Archipelago , 06°02.00’N, 120°44.40’E, 472 m, 17.IX.1909, 1 ovigerous ♀ cl 8.0 mm ( USNM 205085 ) ; stn 5565, SW of Jolo Island , 05°51.42’N, 120°30.30’E, 444 m, 21.IX.1909, 1 ♀ cl 6.0 mm ( USNM 205086 ) .

Indonesia. Same data as holotype, cl 6.3 mm ( MNHN- Na 15159) ; KARUBAR, stn CP 84, Tanimbar Islands , 09°23’N, 131°09’E, 275- 246 m, 4.XI.1991, 2 ovigerous ♀♀ cl 6.2, 7.3 mm (MNHN-Na 15160) .

DISTRIBUTION. — Western Pacific : Philippines and Indonesia ; 246-472 m.

SIZE. — Females cl 6.0- 7.7 mm, ovigerous females cl 6.2-7.7 mm; males unknown.

ETYMOLOGY. — From the Latin prefix e - (non) and carina (ridge), and referring to the absence of a distinct median carina on the third abdominal somite.

DESCRIPTION

Rostrum ( Fig. 11A, B ) strongly compressed laterally, styliform with relatively deep ventral blade, nearly straight or slightly upturned, overreaching distal margin of first segment of antennular peduncle, but not reaching distal margin of second segment; dorsal surface weakly ridged in midline, bearing numerous short to long setae in proximal 0.70 and extending onto anterior part of carapace; lateral tooth strong, arising from 0.40-0.50 of rostrum; lateral face slightly concave at base, with sharp lateral carina extending to distal 0.20 of rostral length; ventral margin strongly convex, unarmed, but with two rows of short setae.

Carapace ( Figs 10 ; 11A, B ) 1.10-1.20 times as long as wide. Middorsal carina not sharp except for two median teeth, extending to 0.70 of carapace length; two middorsal teeth relatively small, epigastric tooth falling far short of base of rostrum, arising at 0.20 of carapace length; second tooth slightly smaller than first, arising at about 0.60 of carapace length. Antennal tooth small, not reaching anterior margin of cornea of eye. Branchiostegal tooth directed forward, falling short of anterior margin of antennal basicerite. Pterygostomian tooth tiny. Lateral surface of carapace with relatively large hepatic and one or two small post-hepatic teeth, but epibranchial tooth absent; post-hepatic tooth arising inferior to level of hepatic tooth; epibranchial carina obsolete.

Sternal tooth on fifth thoracic somite absent in spawning female.

Second abdominal somite ( Figs 10 ; 11C ) with low, triangular plateau on posterior half of tergum, delimited by row of long setae. Third somite weakly elevated posteriorly on tergum, but without distinct middorsal carina; posterodorsal margin of somite weakly produced posteriorly. Sixth somite about two times as long as high; dorsal surface flattened on midline.Telson ( Fig. 11D, E ) with two pairs of minute dorsolateral spines; lateral margin with low, but distinct lobe subproximally; two mesial spines at posterolateral angle long, very slender; terminal process acutely or subacutely pointed.

Cornea of eye ( Fig. 11A, B ) spherical, maximum diameter 0.20-0.22 of carapace length.

Antennular peduncle ( Fig. 11A, B ) reaching 0.30-0.35 of antennal scale; stylocerite not reaching distal margin of first segment, somewhat compressed laterally; lateral flagellum composed of about 11- 13 articles in females; mesial flagellum composed of about 11-12 articles in females. Antennal scale ( Fig. 11A ) about 0.70-0.75 of carapace length and about 2.8 times as long as wide, lateral margin nearly straight, distal blade obliquely, roundly truncate; basicerite with relatively large ventrolateral spine; carpocerite slightly overreaching midlength of antennal scale.

Third maxilliped ( Fig. 12A ) reaching antennal scale by tip of ultimate segment; ultimate segment subequal in length to penultimate segment; antepenultimate segment strongly flattened dorsoventrally, somewhat foliaceus.

First pereopod ( Fig. 12B, C ) with palm about 3.20-3.30 times as long as wide; cutting edge of palm oblique; pollex relatively large, not recurved; carpus armed with two small teeth on distolateral margin; merus with strong dorsodistal tooth not reaching distal margin of anteriorly extended carpus, distolateral tooth small, blunt; ventral carina of merus terminating in sharp tooth (occasionally tooth absent). Second pereopod ( Fig. 12D ) far falling short of midlength of merus of first pereopod; dactylus about half length of propodus; propodus not widened distally. Third pereopod ( Fig. 12E ) very slender; ischium 3.0-3.1 times as long as merus. Fourth pereopod ( Fig. 12F ) moderately slender, overreaching antennal scale by length of dactylus and 0.30 of propodus; dactylus ( Fig. 12G, H ) slender, 0.50-0.55 times as long as propodus, slightly flattened dorsoventrally, terminating in acute unguis exceeded by tuft of setae arising from lateral of base of unguis; propodus with distal tuft of setae ( Fig. 12G ); carpus 0.80-0.85 as long as propodus; merus about 10.0-10.1 times as long as wide, unarmed on dorsodistal margin; ischium about 0.55-0.60 times as long as merus. Fifth pereopod ( Fig. 12I ) similar to fourth, overreaching antennal scale by length of dactylus and 0.20 of propodus; ischium 0.45-0.50 times as long as merus.

Coloration

Unknown.

REMARKS

Lissosabinea ecarina n. sp. is most similar to L. indica , both occurring in Indonesian waters. These two species differ from other congeners in the presence of two median, post-hepatic and epibranchial teeth on the carapace, the possession of a low, triangular plateau on the second abdominal somite in females and the somewhat broadened, foliaceous antepenultimate segment of the third maxilliped. The lack of a conspicuous median carina on the third abdominal somite distinguishes L. ecarina n. sp. from L. indica . In L. indica , the tergum of the third abdominal somite is somewhat compressed laterally in the midline, forming a distinct carina. Also, in comparison with L. indica , the ventral blade of the rostrum of L. ecarina n. sp. is deeper and the dactylus of the fourth pereopod is longer (more than half length of the propodus versus less than half of it). The posthepatic tooth is aligned with the hepatic tooth in L. indica , while it arises somewhat inferior to the level of the hepatic tooth in L. ecarina n. sp.

Chace (1984) reported L. indica (as Sabinea ) on the basis of one specimen from Indonesia and two specimens from the Philippines. Reexamination of these specimens has revealed that only the specimen from Indonesia represents the true L. indica . The two specimens from the Philippines are here referred to L. ecarina n. sp.

Figures

FIG. 10. — Lissosabinea ecarina n. sp., entire animal in lateral view,Banda Sea,Indonesia,KARUBAR,stn CP 25,holotype ♀ cl 7.7 mm (MNHN-Na 15158). Scale bar: 5 mm.

FIG. 11. — Lissosabinea ecarina n. sp., Banda Sea, Indonesia,KARUBAR,stn CP 25, holotype ♀ cl 7.7 mm (MNHN-Na 15158): A, carapace and cephalic appendages,dorsal view (tegumental scales omitted); B, anterior part of carapace and cephalic appendages,lateral view; C, abdomen, dorsal view; D, telson, dorsal view (tegumental scales omitted); E, posterior part of telson, dorsal view. Scale bars: A-C, 2 mm; D, 1 mm; E, 0.5 mm.

FIG. 12. — Lissosabinea ecarina n. sp., left appendages, Banda Sea, Indonesia, KARUBAR, stn CP 25, holotype ♀ cl 7.7 mm (MNHN- Na 15158): 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, same, detail of distal part of dactylus; I, fifth pereopod, lateral view. Scale bars: A-C, E, F, I, 2 mm; D, G, 1 mm; H, 0.5 mm.