Alijinocaris
|
publication ID |
https://doi.org/ 10.1080/00222930400002499 |
|
persistent identifier |
https://treatment.plazi.org/id/050D1914-FFE0-FF9F-FEF2-FE2FFDAF4ED5 |
|
treatment provided by |
Carolina |
|
scientific name |
Alijinocaris |
| status |
|
AlIJinocaris breIJitelsonis Kikuchi and Hashimoto, 2000
( Figures 21 View Figure 21 , 22 View Figure 22 , 29 View Figure 29 ) Alυinocaris breυitelsonis Kikuchi and Hashimoto 2000, p 136 (part), Figures 1 View Figure 1 , 2 View Figure 2 [type
locality: Depression C, Minami-Ensei Knoll, Okinawa Trough, 28 ° 23.359N ,
127 ° 38.389E, 705 m].
Material examined
Okinawa Trough. DS Shinkai 2000 : dive 547, Depression C, Minami-Ensei Knoll , 28 ° 23.359N, 127 ° 38.389E, 705 m, 3 June 1991, suction sampler, coll. J. Hashimoto, one ovigerous female CL 13.8 mm (holotype; NSMT-Cr 12454) GoogleMaps .
Description
Body moderately robust.
Rostrum ( Figure 21A, B View Figure 21 ) directed forward, slightly curved dorsally, 0.55 times carapace length, reaching distal margin of second segment of antennular peduncle; dorsal margin armed with 13 teeth, including eight teeth on rostrum proper and five relatively large teeth on carapace posterior to orbital margin, posteriormost tooth arising from 0.38 of carapace length; ventral margin armed with seven small teeth on anterior 0.60. Carapace ( Figure 21A, C View Figure 21 ) 0.70 times as wide as long; postrostral median ridge high, extending to 0.70 of carapace length, dorsal angle about 150 °; pterygostomian tooth weakly produced anteriorly, subequal in size to antennal tooth, slightly exceeding antennal tooth; postantennal groove obsolete; branchial region not particularly inflated.
Third abdominal pleuron unarmed. Fourth abdominal pleuron ( Figure 21D View Figure 21 ) with three tiny teeth on posteroventral margin. Fifth abdominal pleuron with strong posteroventral tooth and one additional tooth on posterior margin. Sixth abdominal somite 1.40 times longer than proximal height. Telson ( Figure 21E View Figure 21 ) falling somewhat short of posterior margin of uropodal endopod, length 2.70 times anterior width and 4.30 times posterior width; armed with six or seven dorsolateral spines; posterior margin ( Figure 21F View Figure 21 ) moderately convex, armed with six pairs of spines (second pair longest and third pair shortest) and two pairs of plumose setae subequal in length to longest second spine.
Antennular peduncle ( Figure 21B View Figure 21 ) moderately stout, second segment 1.80 times as long as wide. Antennal scale ( Figure 22A View Figure 22 ) half length of carapace, 1.87 times longer than wide; lateral margin straight, weakly diverging anteriorly against dorsal median ridge; distolateral tooth moderately broad, directed anteriorly, not reaching broadly rounded distal margin of blade.
First pereopod ( Figure 22B View Figure 22 ) as illustrated; greatest height of palm 0.48 length of chela ( Figure 22C View Figure 22 ); dactylus ( Figure 22C View Figure 22 ) subequal in length to palm. Third pereopod ( Figure 22D View Figure 22 ) moderately slender; dactylus ( Figure 22E View Figure 22 ) with accessory spinules increasing in size distally; carpus 0.68 times as long as propodus; merus about 7.30 times as long as greatest height.
Size
Only the ovigerous female holotype is known for this species. CL 13.8 mm. TL ca 57 mm.
Distribution and habitat
Known only from the type locality in Minami-Ensei Knoll ( Figure 29 View Figure 29 ), at a depth of 705 m. This species occurs at a hydrothermally influenced area. Alυinocaris dissimilis sp. nov. and Shinkaicaris leurokolos comb. nov. occurred sympatrically.
Remarks
Re-examination of the type series and some of the non-type specimens referred to A. breυitelsonis by Kikuchi and Hashimoto (2000) has disclosed that two species of Alυinocaris, one unidentified species of Opaepele and Shinkaicaris leurokolos comb. nov. were confounded by these authors. The paratypes of A. breυitelsonis and non-type specimens referred to A. breυitelsonis are here assigned to A. dissimilis sp. nov. This new species is readily separated from A. breυitelsonis by having far fewer ventral teeth on the rostrum and by the setal fringe of the posterior margin of the telson. So far, A. breυitelsonis is represented only by the holotype.
The possession of more than two pairs of spines on the posterior margin of the telson links A. breυitelsonis to A. lusca and A. stactophila . As Kikuchi and Hashimoto (2000) correctly pointed out, the shorter telson, which falls short of the posterior end of the uropod, distinguishes A. breυitelsonis from A. lusca . Other differences among the three species are discussed under ‘‘Remarks’’ for A. lusca .
It is interesting to compare A. breυitelsonis with A. longirostris because of their superficial similarity and the proximity of the known localities. Other than the armature of the posterior margin of the telson, A. breυitelsonis differs from A. longirostris in the less produced pterygostomian tooth of the carapace.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.