Two new species of deep-sea leptostracans (Crustacea: Phyllocarida: Leptostraca) from the North-West Pacific

Resumo

Small collections of leptostracans (4 specimens and 1 defective specimen) was collected with the help of the epibenthic sledge (EBS) in August 2012 in the deep-sea basin at depth 5245–5421 m in the region to east of the Kuril-Kamchatka Trench during the Russian-German KuramBio expedition. All these specimens relate to two new species of genera Sarsinebalia and Nebaliella from family Nebaliidae. Sarsinebalia pseudotyphlops sp. nov. differ from S. kunyensis, S. cristoboi and S. urgorrii by compound eyes gud. Eyes of S. pseudotyphlops have not discernible ommatidia and pigment. S. pseudotyphlops differ from S. typhlops and S. biscayensis by next characteristic: supra-orbital plate of S. pseudotyphlops reach only basal third of eye dorsally; antennular flagellum is 1.6 length of antennular scale; S. pseudotyphlops has 2-segmented endopod of maxilla 2; lateral border of furcal rami is by this species smooth, without set; exopod of pleopod 1 has by S. pseudotyphlops with 7 small and 2 long spines on dorsolateral border and 1 stout spine and 4 very long setae on apex; protopod of pleopod 4 has by S. pseudotyphlops on distal border between exopod and endopod nearly rectangular process. Moreover, S. pseudotyphlops differ from two other species of compound and arming of pleopods 5 and 6. Nebaliella kurila sp. nov. separate from the other species of Nebaliella the unique characters of compound articles 1 and 2 on peduncle of antenna, exopod of pleopod 1, and minimal value for this genus ratio length of pleopod 6 to length of pleonite 6. Moreover, N. kurila has carina on anterolateral lower corner of carapace; ratio of the rostral flange to exposed keel 1:1; 6-segmented palp of maxilla 1 and endopod of toracopod 8; and has not proximalventral tuberculate process on rostrum and stout spinulose process on article 2 of mandibular palp.