Wellstenhelia euterpoides Gómez & Cruz-Barraza 2021, sp. nov.
Creators: name: Gómez, Samuel
name: Cruz-Barraza, José Antonio
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Hexanauplia
Harpacticoida
Miraciidae
Wellstenhelia
Wellstenhelia euterpoides

description: Wellstenhelia euterpoides sp. nov.
(Figs. 2–7)
urn:lsid:zoobank.org:act: 5770D659-D8D8-461D-9B8C-674CB24ED2A1
Type locality. Off La Bocana, Baja California Sur (Eastern Tropical Pacific), Mexico; Talud XV cruise, sampling station 20 (26.54278°N, 113.93889°W); depth, 479 m; organic carbon content, 3.18%; organic matter content, 5.47%; sand 47.08%; clay, 7.75%; silt, 45.16%.
Other localities. Off San Pablo Bay, Baja California Sur (Eastern Tropical Pacific), Mexico; Talud XV cruise, sampling station 24 (27.11806°N, 114.6008°W); depth, 1039 m; organic carbon content, 3.26%; organic matter content, 5.60%; sand 35.53%; clay, 7.95%; silt, 56.52%.
Central Guaymas Basin, Gulf of California, Mexico; Talud X cruise, sampling station 22 (27.0167°N, 110.8944°W); depth, 1642 m; organic carbon content, 4.27%; organic matter content, 7.35%; sand, 9.56%; clay, 11.34%; silt, 79.10%.
Specimens examined. From the type locality. Adult female holotype preserved in alcohol (EMUCOP-020812- 03) from which the left antenna was dissected and mounted onto one slide; August 2, 2012; coll. S. Gómez.
From other localities. Adult female paratype dissected and mounted onto eight slides (EMUCOP-010812- 09) from sampling station 24 (Talud XV cruise; August 1, 2012; coll. S. Gómez), and dissected female paratype mounted onto six slides (EMUCOP-130207-03) from sampling station 22 (Talud X cruise; February 13, 2007; coll. S. Gómez).
Etymology. The Ancient Greek sufix εἶΔΟΣ, eîdos, meaning likeness makes reference to the resemblance of the new species with W. euterpe.
Description of female. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 490 µm to 580 µm (n = 2); habitus pyriform, widest at posterior end of cephalothorax, tapering posteriad (Fig. 2A).
Prosome consisting of cephalothorax with fused first pedigerous somite, and second to fourth free pedigerous somites. Cephalothorax slightly longer than wide, with hyaline fringe broad and smooth. Free pedigerous somites without expansions laterally nor dorsally; without spinular ornamentation; integument smooth and weakly sclerotized; hyaline fringe of second and third pedigerous somites broad and smooth, of fourth pedigerous somite narrower; width of second to fourth pedigerous somites decreasing progressively.
Urosome (Fig. 2B–D) consisting of fifth pedigerous somite (first urosomite), genital double-somite (genital— second urosomite—and third urosomites fused), two free urosomites, and anal somite; urosomites without expansions laterally nor dorsally; integument weakly sclerotized.
Fifth pedigerous somite visibly narrow; with surface sensilla as shown (Fig. 2B–C); without spinular ornamentation; hyaline fringe narrow.
Second and third urosomites completely fused ventrally (Fig. 2D) forming genital double-somite, with dorsolateral trace of division (Fig. 2B–C) between original segments; 1.2 times as long as wide, widest part measured proximally close to P6; anterior half of genital double-somite with few sensilla and two sets of spinules dorsally as shown (Fig. 2B), ventrally without surface ornamentation; posterior half of genital double-somite with dorsolateral sensilla and spinules as shown (Fig. 2B–C), ventrally with two sensilla and medial row of spinules (Fig. 2D), posterior hyaline fringe broad and smooth. Genital complex hardly distinguishable; copulatory pores not exposed; paired genital apertures located ventrolaterally and covered by P6.
Fourth urosomite with few sensilla dorsally (Fig. 2B), with few sensilla and some spinules laterally (Fig. 2C), and with two sensilla and medial row of spinules ventrally (Fig. 2D); posterior hyaline fringe broad and smooth.
Fifth urosomite without sensilla or spinules (Fig. 2B–D).
Anal somite three times as wide as long (Fig. 2A–B); with spinules around joint of caudal rami (Fig. 2A–D); ventrally (Fig. 2D) with spinules along each side of medial cleft and with two pores. Anal operculum semicircular, flanked by one sensillum on each side, posterior margin with transverse row of small spinules (Fig. 2A–B).
Caudal rami elongate, about 6.4 times as long as wide (Fig. 2A–E) and as long as fourth, fifth and anal somite combined; with small spinules at base of setae I and II, and III (Fig. 2E); with seven elements (Fig. 2A–G); seta I a spine, ventral to seta II, both subdistal on lateral margin; seta III subdistal, arising ventrally; seta IV and V distal, with fracture plane, the former seemingly normal and with outer spinules, the latter rat-like and bipinnate; seta VI issuing at inner distal corner; dorsal seta VII triarticulate at base, situated subdistally close to inner margin.
Rostrum (Fig. 3A) trapezoidal, not fused to cephalothorax, bifid, with two subdistal sensilla, and with a proximal dorsal pore.
Antennule (Fig. 3B) eight-segmented; all segments smooth, except for spinular row on first segment, the latter without pore. All setae smooth; second segment at least with one (some setae detached during dissection), third segment with one seta with fracture plane; seventh and eighth segment with two articulated setae.Armature formula: 1(1); 2(12?); 3(9); 4(4 + (1 + ae)), 5(2); 6(4); 7(4); 8(4 + acro). Acrothek consisting of two setae and one minute aesthetasc fused basally.
Antenna (Fig. 3C–D). Coxa short, with some outer long slender spinules, and some inner small ones (Fig. 3D). Allobasis with remain of original division between basis and first endopodal segment, as long as free endopodal segment, with long inner spinules proximally, and smaller ones close to base of exopod, with one pinnate abexopodal seta arising midway inner margin. Free endopodal segment elongate, with inner spinules as shown, with two outer subdistal frills; armature composed of two lateral spines and two accompanying slender setae, distally with one inner apical spine, three apical geniculate setae and one slender element, and one outer distal pinnate element fused basally to slender seta. Exopod three-segmented; third segment longest, about eight times as long as wide, and 1.3 times as long as first segment, second segment smallest; first and third segment with spinules as shown, second segment without spinular ornamentation; first and second segment with one seta, third segment with one proximal and three distal setae, none of which fused basally.
Mandible (Fig. 4A). Coxa relatively short. Gnathobase wide; ventral distal corner produced into small sharp semi-hyaline process; with two strong and several smaller teeth, two spinules, one pyriform spine, and one bipinnate seta. Basis with wide base, rather rectangular, with some medial and some subdistal spinules as shown, with three distal outer setae. Exopod arising from short pedestal, elongate, about three times as long as wide, and 0.4 times as long as basis, tapering distally, with three lateral and three apical slender setae none of which fused basally. Endopod recurved, twisted over exopod, with three lateral setae, and five distal elements (four slender setae and one long element fused to endopod and with hyaline flange).
Maxillule (Fig. 4B). Arthrite of praecoxa with two surface setae and eight distal elements one of which strongly spinulose, and one lateral spinulose recurved seta. Coxa with three setae. Basis with two endites, each apparently with three setae. Exopod and endopod fused basally, separated from basis, one-segmented; endopod larger than exopod, with four setae; exopod small, with two setae.
Maxilla (Fig. 5A). Large syncoxa with spinular ornamentation as shown; with three endites; proximal endite smallest, bilobate, each lobe with one naked and one pinnate seta; middle and distal endites elongate, the latter slightly longer, with two spinulose and one naked seta each. Basis drawn out into strong spinulose claw, additionally with strong spine and two slender setae. Endopod rather elongate, with five (or six?) slender setae.
Maxilliped (Fig. 5B) subchelate. Syncoxa elongate, rectangular; about 2.2 times as long as wide, with slender inner spinules, with two subdistal setae of which one spinulose and one bare, and one distal bare seta arising from long pedestal. Basis visibly shorter than syncoxa, oval, with slender outer spinules, with one anterior and one posterior inner spinular row as depicted; with two distal setae subequal in length. Endopod one-segmented, with one claw-like element and one seta.
P1 (Fig.6A).Intercoxal sclerite (not shown) transversely elongate, nearly straight, without surface ornamentation. Coxa massive, nearly as long as wide, with spinular ornamentation as shown. Basis with spinules proximally on inner margin, at base of inner and outer spines, and between rami. Exopod three-segmented, reaching distal third of ENP2; exopodal segments subequal in length; all segments without outer nor inner acute distal processes, no pores detected on exopodal segments; EXP1 and EXP2 with longitudinal row of outer spinules, EXP1 without, EXP2 with inner seta; EXP3 with some spinules at base of proximal outer element, with two outer spines and two apical setae. Endopod two-segmented, longer than exopod; no pores detected on exopodal segments; ENP1 with small outer acute process, with longitudinal row of outer spinules, and with one inner seta; ENP2 elongate, about twice as long as ENP1, with inner slender spinules proximally and with longitudinal row of stronger spinules along inner margin, with one inner proximal, one inner distal and one distal seta, and one outer distal spine.
P2–P3 (Figs. 6B, 7A). Intercoxal sclerite (not shown) not transversely elongate, trapezoidal, with strong pointed process on distal outer corners, without surface ornamentation. Coxa with outer spinular rows proximally and subdistally. Basis with outer seta (of P2 visibly shorter); with acute process at inner distal corner and between rami, the former larger; with slender long spinules on inner margin. Exopod three-segmented, reaching slightly beyond ENP2; EXP1 and EXP3 longest; EXP1 and EXP2 with outer acute distal process, with longitudinal row of outer spinules and with inner distal frill, with inner seta; EXP1 without, EXP2 with subdistal outer pore; EXP3 with outer spinules as shown, of P3 without, of P2 with medial pore on distal third, with one (P2) or two (P3) inner setae, with two apical elements, and two outer spines. Endopod three-segmented, longer than EXP; ENP1 shortest, ENP2 and ENP3 of about the same length; ENP1 and ENP2 with outer acute and inner small process distally, with longitudinal row of outer spinules, with small spinules at base of outer process; P2 ENP1 with, P3 ENP1 without pore, P2 ENP2 and P3 ENP2 without pore, P2 ENP3 and P3 ENP3 with medial subdistal pore; ENP1 with inner strong spine-like element, ENP2 with one inner seta as depicted, ENP3 with one (P2) or three (P3) inner setae, two apical elements and one outer apical spine.
P4 (Fig. 7B). Intercoxal sclerite (not shown) not transversely elongate, trapezoidal, with strong pointed process on distal outer corners, without surface ornamentation. Coxa and basis as in P3 but basis seemingly without inner ornamentation and inner process less developed. Exopod three-segmented, longer than endopod; exopodal segments of about the same length; EXP1 and EXP2 with outer acute distal process, with longitudinal rows of outer spinules and with inner distal frill, EXP1 without, EXP2 with outer subdistal pore, both segments with inner seta; EXP3 with small outer spinules, without pore, with three inner setae, two apical elements, and two outer spines. Endopod threesegmented, barely reaching beyond EXP2; ENP1 shortest, ENP2 and ENP3 of about the same length; ENP1 and ENP2 with outer acute and small inner process distally, with longitudinal row of outer spinules, with small spinules at base of outer process, without pore, inner element of ENP1 a long stiff element, ENP2 with inner seta; ENP3 with longitudinal row of outer spinules and with medial pore subdistally, with two inner setae, two apical elements and one outer spine.
Setal formula of swimming legs as follows:
P5 (Fig. 7C). Baseoendopod pentagonal; endopodal lobe well-developed, reaching middle of EXP, with three setae. Exopod oval, 1.4 times as long as wide; with some outer small spinules proximally; with five setae, of which second innermost shortest.
P6 (Fig.2D) a minute flap covering ventrolateral genital aperture; fused to somite; without surface ornamentation; with one slender seta.
Male. Unknown.
description: Published as part of Gómez, Samuel & Cruz-Barraza, José Antonio, 2021, On some deep-sea Stenheliinae from the Gulf of California and the west coast of the Baja California Peninsula (Mexico): Wellstenhelia euterpoides sp. nov., and Wellstenvalia wellsi gen. et sp. nov. (Copepoda: Harpacticoida: Miraciidae), pp. 117-150 in Zootaxa 5051 (1) on pages 120-127, DOI: 10.11646/zootaxa.5051.1.10, http://zenodo.org/record/5563515