Probathylepas faxian, Ren, Xian-Qiu & Sha, Zhong-Li, 2015

Ren, Xian-Qiu & Sha, Zhong-Li, 2015, Probathylepadidae, a new family of Scalpelliformes (Thoracica: Cirripedia: Crustacea), for Probathylepas faxian gen. nov., sp. nov., from a hydrothermal vent in the Okinawa Trough, Zootaxa 4033 (1), pp. 144-150 : 146-149

Probathylepas faxian sp. nov.

Figs. 1 , 2 , 3

Material examined. Holotype: MBM 240865, ROV-3, RY0069; hermaphrodite, body length 8.6 mm; capitular length 6.2 mm, width 5.9 mm, thickness 2.8 mm, capitular basal width 3.8 mm; peduncular length 2.4 mm, peduncular width 1.6 mm. Collected from a hydrothermal vent area in the Okinawa Trough (126° 58.46E, 27° 32.78N) by research vessel “Kexue” and ROV “ Faxian ”. Attached to sediment grains, together with Neoverruca intermedia Sha & Ren, 2015 in press; 16.04.2014; Sha Zhong-Li and Zhang Jun-Long coll.

Description. Capitulum subtriangular, laterally compressed, 30 plates, approximate, covered by thin, transparent cuticle; 8 primary large calcareous plates (rostrum, carina, paired scuta, terga and latera) and two whorls of small imbricating supplementary plates, each whorl with 11 plates. Umbo of all capitular plates apical. Apical regions of scuta and terga separated, outwardly curved. Scutum narrow, long, triangular, occludent margin arched, tergal margin concave, umbo apical, apical part slightly overlapping occludent margin of tergum, growth lines distinct, outer surface with fine hairs; apical region of inner surface, above deep depression of scutal adductor muscle, with short, deep groove bordered on each side by a longitudinal ridge. Tergum quadrangular, carinal margin straight, umbo apical, apico-basal rib inconspicuous, growth lines distinct, inner surface smooth. Rostrum triangular, height subequal to width, umbo apical, extending beyond occludent margin of scutum, basal margin arched, inner surface longitudinally concave, smooth. Carina narrow, long, triangular, umbo apical, strongly projecting outward beyond carinal margin of tergum, growth lines distinct, basal margin arched, inner surface smooth, longitudinally concave. Latus small, triangular, narrow, long, umbo apical. Two whorls of small imbricating supplementary plates; each plate irregularly triangular, growth lines distinct, umbo apical, inner surface smooth; upper part of each lower plate slightly covering basal part of upper plate.

Capitulo-peduncular junction distinct. Peduncle shorter than capitulum, columnar, smooth, without scales.

Posterior part of mouth with conical protuberance between first cirri. Frontal part of labrum slightly bullate, medial part of cutting edge slightly concave, with fine short hairs, crest with row of small teeth. Mandible with 3 teeth, consisting of 1 strong superior spine and 2 low broad teeth each supporting single row of fine, sharp spines along superior margins, lower angle with fine-toothed comb of 12 similar spines, small spines and terminal pectination. Frontal margin of maxilla I straight, lacking step-like cutting edge, with row of spines. Maxilla II setose, distal tip acute. Palp triangular, setose, distal tip slightly acute.

Dorsal surface of prosoma without filamentary appendages.

Numbers of segments of rami of cirri I–IV of holotype as follows:

I II III IV V VI

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+ 27 24 9 19 31 39 25 36 42 32 33 36+ Cirrus I fine, long, with proximal segments of both rami broad, short; frontal margin densely setose, distal articles antenniform. Cirrus II widely separated from cirrus I, shorter than remaining cirri; anterior ramus shorter, thicker than posterior, length approximately 1/2 posterior ramus, frontal margin of each article densely setose. Cirrus III with intermediate segments narrow, long, frontal margin bearing 2 pairs of long, stout setae near terminal ends of segments. Cirri IV–VI long, intermediate segments with 2–3 pairs of setae near terminal ends of segments. Basal part of cirrus IV without caudal appendage.

Penis well developed, slender,long, length approximately 2.5 times length of cirrus VI, indistinctly annulated and terminal sparse setae.

Complemental male unknown.

Etymology. faxian in reference to to find or discover remotely operated vehicle (ROV) " Faxian " of China.

Figures

FIGURE 1. Probathylepas faxian sp. nov., a – c, holotype (MBM 240865) a. individual viewed from right side; b. carinal view; c. rostral view;

FIGURE 2. Probathylepas faxian sp. nov., a – l, holotype (MBM 240865) a. individual viewed from right side; b. individual viewed from left side; c. rostral view; d. carinal view; e, f. scutum; g, h. tergum; i, j. latus; k, l. supplementary plates.

FIGURE 3. Probathylepas faxian sp. nov., a – m, holotype (MBM 240865) a. soft body; b. dorsal view of basal parts of cirrus VI and penis; c. lateral view of mouth; d. labrum and palp; e. mandible; f. maxilla I; g. maxilla II; h. cirrus I; i. cirrus II; j. intermediate segments of cirrus III; k. terminal segments of cirrus III; l. basal parts of cirrus VI and penis; m. terminal end of penis.