Cetiopyge lemei, Esquete & Cunha, 2018

Esquete, Patricia & Cunha, Marina R., 2018, Additions to the Tanaidomorpha (Crustacea: Tanaidacea) from mud volcanoes and coral mounds of the Gulf of Cadiz and Horseshoe Continental Rise, Zootaxa 4377 (4), pp. 517-541 : 531-535

Cetiopyge lemei sp. nov.

( Figs 8–10 )

Material examined. Holotype— ♀ ( MNCN 20.04/11447), cruise MSM 01-03, station MSM 01-3_344, collected from the experimental chamber of a FLUFO lander, 16.05.2006, GoC, Capitan Arutyunov MV, 35°39.697'N, 07°20.038'W, 1320 m depth, crater of MV; mud breccia.

Paratypes— seven ♀♀ ( DBUA0002221.02 ), same data as holotype. All coll. MRC

Further specimens — Gulf of Cadiz—Mud volcanoes. Captain Arutyunov MV: station MSM01-03 _225, collected from the experimental chamber of a BIGO lander, 0 4.05.2006, 35°39.682'N, 07°19.882'W, 1320 m, crater of MV, mud breccia, two neuters ( DBUA0002222.01 ), coll . MRC. Horseshoe Continental Rise—Mud volcanoes. M. Ivanov MV: station M86-5_329, USNEL boxcore, 0 1.03.2012, 35°44.338'N, 10°12.056'W, 4492 m, crater of MV; mud breccia covered by hemipelagic sediments, one neuter (DBUAXXXX); Abzu MV: station M86-5_369, USNEL boxcore, 0 8.03.2012, 35°45.045'N, 10°19.018'W, 4550 m, crater of MV; mud breccia covered by hemipelagic sediments, one neuter (DBUA0002222.02). All coll. MRC.

Etymology. Named after “LEME”, acronym for the “Laboratorio de Ecologia Marinha e Estuarina” (Laboratory of Marine and Estuarine Ecology) of the University of Aveiro.

Diagnosis. Cephalothorax as long as three first pereonites combined. Mandible pars incisiva with three cusps. Maxillule endite with nine spines. Maxilliped endite with two cusps. Maxilliped palp article 2 with one outer and two simple inner setae, article 3 with two simple inner setae, article 4 with three distal and one subdistal setae. Chela twice as long as broad, fixed finger with proximal invagination, dactylus shorter than fixed finger, naked, with medioventral ventral tooth. Pereopods 1–3 propodus with one subdistal serrulate spine.

Description of female DBUA0002221.01. Body ( Fig. 8A, B ) length 1.6 mm, 4.4 times as long as broad. Cephalothorax about as long as broad, as long as pereonites 1–3; eyelobes present without visual elements. Pereonites all broader than long, pereonites 4–5 longest. Pleon and pleotelson swollen. All pleonites subequal, without pleopods. Pleotelson semicircular, longer than four pleonites.

Antennule ( Fig. 9A ) article 1 2.1 times as long as broad, with two inner tufts of penicillate setae. Article 2 0.5 times as long as article 1, with inner simple seta. Article 3 broader than long, 0.2 times as long as article 2, with three setae. Article 4 3.5 times as long as previous, with tuft of distal setae and one aesthetasc.

Antenna ( Fig. 9B ) article 1 1.3 times as long as broad, naked. Articles 2 and 3 with one dorsal seta. Article 4 4.0 times as long as broad, with medial and subdistal penicillate setae. Article 5 0.3 times as long as article 4, with distal seta. Article 6 small, as long as broad, with tuft of setae.

Mouthparts. Labrum semicircular (not figured). Left mandible ( Fig. 9C ) pars incisiva with three lobes, lacinia mobilis as long as pars incisiva, rectangular; pars molaris about as long as pars incisiva, armed with denticles and setules. Right mandible ( Fig. 9D ) as left, but without lacinia mobilis. Maxillule endite ( Fig. 9E ) with nine distal spines, two of them bifurcate; palp ( Fig. 9F ) with two distal setae. Maxilla not recovered.

Maxilliped ( Fig. 9G ) basis fused; palp article 1 naked, article 2 with one outer and three inner setae, article 3 with two inner setae, article 4 with one subdistal and three distal setae.

Cheliped ( Fig. 10A ) basis attached via sclerite, naked. Merus as long as basis, naked. Carpus 1.2 times as long as broad, with one ventral and one dorsodistal setae. Propodus palm with four setae near dactylus insertion; fixed finger with two ventral and three inner setae, cutting edge with subdistal denticle. Dactylus shorter than fixed finger, naked, with ventral tooth.

Pereopod 1 ( Fig. 10B ) coxa naked. Basis curved, 7.9 times as long as broad, naked. Ischium with ventral seta. Merus 0.3 times as long as basis, with ventrodistal spine. Carpus about as long as merus, distally with two setules, one short and one long spines. Propodus 1.3 times as long as carpus, with subdistal seta and ventrodistal spine. Dactylus plus unguis 1.4 times as long as propodus, unguis 1.3 times as long as dactylus.

Pereopods 2–3 ( Fig. 10C, D ) similar to pereopod 1, but basis not curved.

Pereopod 4 ( Fig. 10E ) coxa naked. Basis 4.6 times as long as broad, naked. Ischium naked. Merus 0.4 times as long as broad, with pair of ventrodistal serrulate spines. Carpus 1.1 times as long as merus, with three ventrodistal serrulate spines and one dorsodistal seta. Propodus 1.1 times as long as carpus, with two ventrodistal serrulate long spines and one dorsodistal, stout, ventrally serrated spine. Dactylus plus unguis 1.7 times as long as propodus, unguis as long as dactylus.

Pereopod 5 ( Fig. 10F ) similar to pereopod 4, but propodus with one dorsodistal long seta instead of stout serrated spine.

Pereopod 6 ( Fig. 10G ) similar to pereopod 4, dactylus with one distal setule.

Uropods ( Fig. 10H ) short, not protruding apex of pleotelson. Protopod as long as first endopod segment, naked. Endopod first segment about as long as broad, naked; second segment 0.5 times as long as first, with one penicillate and three simple setae, one of which longer than total length of uropod. Exopod minute, 0.5 times as long as first endopodal segment, with one long simple seta.

Remarks. Cetiopyge lemei sp. nov. is included within the genus because of the presence of several diagnostic characters, namely the pleon and pleotelson compressed laterally, the presence of bifurcate spines on the maxillule, absence of pleopods on the female, and short uropods with minute exopodite and endopodite second article.

The species described herein is different from the type species, Cetiopyge mira , in the following features: cephalothorax as long as three first pereonites combined instead of two; mandible pars incisiva with three lobes; maxillule endite with nine spines instead of eight; maxilliped endite with two cusps, palp article 2 with two simple setae instead of three, article 4 with three distal setae instead of four; chela twice as long as broad and longer than carpus, fixed finger with proximal invagination, dactylus shorter than fixed finger, naked, with medioventral tooth; all pereopods meri and carpi distinctively more slender; pereopods 1–3 propodus without serrulate dorsal spine, but with one subdistal seta.

Distribution and ecology. This species was found in mud breccia and overlaying hemipelagic sediments collected mostly from active sites of mud volcanoes sitting on the deep-reaching SWIM fault (Capitain Arutyunov, Abzu and Ivanov MVs) at depths between 1320 and 4550 m.

Figures

FIGURE 8. Cetiopyge lemei sp. nov. FeMALe SPecIMeN DBUA0002221.01A: A, hAbITUS (DORSAL VIeW). SPecIMeN DBUA0002221.01B:B, hAbITUS (LATeRAL VIeW).

FIGURE 9. Cetiopyge lemei sp. nov. FeMALe SPecIMeN DBUA0002221.01B: A, ANTeNNULe; B, ANTeNNA; G, MAXILLIPeD. SPecIMeN DBUAXXXX:C, LeFT MANDIbLe;D, RIGhT MANDIbLe;E, MAXILLULe eNDITe;F, MAXILLULe PALP.

FIGURE 10. Cetiopyge lemei sp. nov. FeMALe SPecIMeN DBUA0002221.01B: A, cheLIPeD; B, PeReOPOD 1; C, PeReOPOD 2; D, PeReOPOD 3; E, PeReOPOD 4; F, PeReOPOD 5; G, PeReOPOD 6; H, UROPOD.