Enterocola oligosetosus Kim & Boxshall 2021, sp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Cyclopoida
Ascidicolidae
Enterocola
Enterocola oligosetosus

description: Enterocola oligosetosus sp. nov.   
(Figs. 155, 156)  
 Type material. Holotype ♀ (MNHN-IU-2014-21564), 3 ♀♀ paratypes (MNHN-IU-2014-21565), and 1 ♀ para- type (dissected, MNHN-IU-2014-21478) from aẚdemnum sp.; Guadeloupe, Îlet aux Pigeons, Stn 20, depth 5-12 m, Monniot coll., 27 December 1980.   
 Etymology. The name of the new species refers to the presence of a single seta on the endopod of leg 4.   
 Description of female. Body (Fig. 155 A-C) eruciform, curved dorsally; body length 968 μm in largest dissect- ed specimen; maximum width 386 μm (across second pedigerous somite). Cephalosome clearly defined, 168×263 μm, distinctly narrower than trunk. Trunk inflated, unsegmented, but 4 anterior pedigerous somites defined by lateral constrictions between them; first to third pedigerous somites bearing small dorsolateral tergal folds; fourth pedigerous somite narrower than anterior pedigerous somites, bearing dorsal tergite. Ventral interpodal protrusions absent. Genitoabdomen (Fig. 155D) gradually narrowing posteriorly, 5-segmented; articulations obscure dorsally; articulation between last 2 somites incomplete. Caudal ramus (Fig. 155E) tapering, incompletely articulated from anal somite, about 1.85 times longer than wide (76×41 μm), blunt distally; armed with 1 weakly pinnate, dorsal seta at 70% of ramus length; seta length 44 μm, more than half length of ramus.   
Rostrum absent. Antennule (Fig. 155F) incompletely 2-segmented, about 76×40 μm, with inflated proximal two-thirds and narrow distal third; proximal segment with convex posterior margin armed with 3 setae (1 subdistal and 2 distal); distal segment small, 11×7 μm, rectangular, armed with 4 setae on distal margin. Antenna (Fig. 155G) elongate, about 2.7 times longer than wide (145×54 μm), unsegmented, and ornamented with several patches of minute spinules on concave surface; armed with 5 unequal setae, lengths of setae (medial to lateral) 19, 9, 9, 45, and 41 μm, respectively; setae II and III small, close to each other and positioned at mediodistal corner, both setae widely separated from seta I and setae IV and V; seta IV and V distinctly larger than other setae, originating close to each other, positioned at laterodistal corner.  
Labrum (Fig. 155H) with 2 patches of minute spinules on each side of ventral surface; palp densely spinulose, gradually expanded distally. Mandible (Fig. 155H) spinulose, about half as wide as labral palp. Maxillule consisting of precoxa (Fig 156A) and palp (Fig. 156B); precoxa with bifurcate distal part, 1 subdistal tubercle, and endite tipped with 1 seta, (proximally plumose and distally spinulose); palp with 5 spinulose setae on distal margin and 1 naked seta on lateral margin. Maxilla (Fig. 155I) 2-segmented; proximal segment with bifurcate mediodistal process bearing fine spinules distally; distal segment bifurcate distally, with 1 small seta proximally on posterior surface. Maxilliped absent.  
Legs 1-4 each consisting of unarmed, 2-segmented protopod and unsegmented rami (Fig. 156 C-E). Exopods with 3 patches of minute spinules along lateral margin. Endopods of legs 1-3 armed with 2 setae distally, but endopod of leg 4 armed with 1 seta distally (in 1 of 5 examined specimens, endopods of legs 2-4 armed with 1 seta), all setae weakly pinnate. Endopodal segments 59×30, 64×31, 64×30, and 58×33 μm, respectively, in legs 1-4. Lengths of laterodistal and mediodistal setae 59 and 42, 66 and 41, and 68 and 41 μm, respectively, in legs 1-3. Length of distal seta on leg 4 endopod 68 μm.  
Leg 5 (Fig. 155J) unarmed, wider than long (98×180 μm).  
 Male. Unknown.   
 Remarks. This new species is very easily distinguishable from all of its congeners by the possession of a single seta on the endopod of leg 4. The combination of three other character states, the caudal ramus is armed with 1 seta, the antenna is elongate and armed with 5 setae, and the distal setae on the endopods of all swimming legs are pinnate, provides additional evidence supporting the establishment of the new species.
description: Published as part of Kim, Il-Hoi & Boxshall, Geoff A., 2021, Copepods (Cyclopoida) associated with ascidian hosts: Ascidicolidae, Buproridae, Botryllophilidae, and Enteropsidae, with descriptions of 84 new species, pp. 1-286 in Zootaxa 1 on page 237, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/4820443