Comprehensive Description

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General Description

The body is moderately robust, and the integument is thin and soft, but not membranous. The surface is smooth. The rostrum is directed forward, reaching or slightly falling short of the distal margin of the first segment of the antennular peduncle. The rostrum is somewhat depressed dorsoventrally, and is narrowly triangular in a dorsal view. The dorsal margin slopes down anteriorly, and the middorsal line is elevated in a blunt carina, armed with 6–8 tiny to small teeth. The posteriormost tooth arises from just above the posterior margin of the orbit. The ventral surface is nearly flat, and is unarmed. The ventrolateral carina is sharp, and merges into the orbital margin. The carapace is about 1.40 times longer than it is wide. The postrostral median ridge is absent. The antennal tooth is moderately large, and is buttressed with a weak ridge. The pterygostomial tooth is slender, and is strongly produced, reaching well beyond the antennal tooth. The anterolateral margin between the antennal and pterygostomial teeth is concave. The post-antennal groove is shallow, and diverges to the horizontal plane of the carapace. The branchial region is moderately convex.

The eighth thoracic sternite has a long median spur directed anteroventrally.

The abdomen is rounded dorsally. The pleura of the anterior three somites are rounded. The fourth pleuron has a small posteroventral tooth, whilst the fifth pleuron also has a small posteroventral tooth in addition to 1–4 denticles on the posterolateral margin. The sixth somite is about 1.20 times longer than high. The telson does not reach the posterior margin of the uropodal endopod, and has a length about 2.40 times its anterior width and about 3.3 times its posterior width. The telson is armed with 7 or 8 dorsolateral spines that are arranged in a sinuous row on either side. The posterior margin is convex, and bears 2 pairs of spines at lateral angles (the mesial spine is about twice the length of the lateral spine) and about 20 plumose setae that are all longer than the mesial pair of lateral spines.

The eyes are broadly fused mesially, each being unarmed on the anterodorsal surface. The corneal part is imperfectly developed, subovate in outline, and unfaceted.

The antennular peduncle reaches or slightly overreaches the distal margin of the antennal scale. The first segment has a conspicuous proximal tubercle laterally on the dorsal surface, and a strong distolateral tooth that reaches nearly the midlength of the second segment, and a small distomesial tooth. The dorsal surface has a distinct, obliquely longitudinal groove. The stylocerite is sharp, slender, and reaches to the mid-length of the second segment. The second segment is stout, and is about 1.40 times as long as it is wide, with a small distomesial tooth. The flagella are both longer than the carapace.

The antenna has a stout basicerite that bears moderately large ventrolateral and small ventral teeth. The carpocerite is stout, and reaches beyond the midlength of the antennal scale. The antennal scale is 0.38–0.42 times as long as the carapace, and is 1.80–1.90 times longer than wide. The lateral margin is nearly straight, and noticeably diverges against the middorsal ridge. The middorsal ridge on the dorsal surface is conspicuous. There is a moderately broad distolateral tooth. The distal lamella is produced, rounded, and far overreaches the distolateral tooth.

The mandible has a molar process that terminates in a subacute tip. The maxillule has a slightly bilobed endopod, consisting of an inner lobe with 1 long setulose seta apically, and an outer lobe with 2 submarginal minute setae on the outer surface. The maxilla has a moderately broad scaphognathite. The exopod of the first maxilliped is broad, with a small, distinct triangular lobe on the mesial margin, representing a reduced flagellum. The second maxilliped has a stout endopod. The epipod has a stout podobranch that abruptly tapers distally. The third maxilliped overreaches the antennal scale by about 0.30 times the length of the ultimate segment. The ultimate and penultimate segment combined are arcuate. The ultimate segment is distinctly longer than the penultimate segment. It is trigonal in cross section, and has a subtruncate terminal margin with 2 or 3 spines, and a lateral margin with a longitudinal row of spiniform setae. The antepenultimate segment is somewhat flattened dorsoventrally, and is sinuously curved in a dorsal view, bearing 1 slender spine at the ventrolateral distal angle. The dorsal surface of the antepenultimate segment has a prominent tuft of short to long setae proximomesially, and the mesial surface has several obliquely vertical tracts of short stiff setae distal to midlength. The coxa is stout, with a small projection dorsal to the base of the epipod. The epipod is relatively large, and is directed distolaterally, and is subquadrate in a dorsal view.

The first pereopod reaches the midlength of the antennal scale, and is relatively slender. The chela is small. The fingers are curved downward and inward, exceeding 4.0 times the length of palm. The outer surface of both fingers is convex, with the inner concavity having the opposed edges uniformly offset, and closing without a gap. Each finger is armed with a fine row of closely set teeth, with the tip of each finger being slightly spooned. The palm is without a patch of setae on the mesial surface. The carpus is cupped distally to receive the palm. The dorsodistal mesial margin is rounded. The ventrolateral margin is flared into a ridge that terminates in a subacute tooth, whilst the ventromesial surface has grooming apparatus consisting of a patch of dense setae and 1 small spine just proximal to the setal patch. The mesial face is shallowly concave. The merus and ischium are strongly obliquely articulated in a lateral view.

The second pereopod is slightly longer and more slender than the first pereopod. The fingers are slightly longer than the palm, each terminating in a small corneous unguis that cross each other when closed. The cutting edges close without a gap, each being pectinated with a single row of minute corneous teeth. The carpus is longer than the chela. The merus and ischium are obliquely articulated in a lateral view. The ischium is unarmed.

The third to fifth pereopods are moderately slender, and are generally similar in structure and length although the propodus becomes progressively longer and the merus progressively shorter from the third to fifth pereopod. The third pereopod extends beyond the distal margin of the antennal scale by 0.30–0.40 times the length of the propodus. The dactyli are small (0.20–0.22 of the propodal length in third and fourth pereopods; 0.15–0.18 in the fifth), 1.90–2.00 times longer than high. Each is armed with 10 or more corneous spines that are arranged in 2 or 3 rows on the flexor surface. The propodi of the third and fourth pereopods have slender spinules arranged in 2 rows on the ventral surface, whilst the propodus of the fifth pereopod has numerous spiniform setulose setae arranged in 3 or 4 rows on the distal half of the ventral surface. The carpi are shorter than the propodi. The meri and ischia are always unarmed.

The appendices internae on second to fourth pleopods are small and slender. Those on second to fourth pleopods taper distally, and are without a terminal cluster of cincinnuli. The appendix internae of the fifth pleopod is better developed than others, having a terminal cluster of cincinnuli.

The protopod of the uropod has an acute posterolateral angle. The endopod is slightly shorter than the exopod. The exopod has 2 movable spines at the posterolateral angle.

(Komai & Chan, 2010)


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