Enterocola angustus 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 angustus

description: Enterocola angustus sp. nov.   
(Figs. 146, 147)  
 Type material. Holotype ♀ (MNHN-IU-2014-21557) and 1 ♀ paratype (dissected, MNHN-IU-2014-21474) from aẚdemnum nçcturnum Monniot F. & Monniot C., 1997 (MNHN-IT-2008-3178 = MNHN A2 /DID.C/404); Tanzania, Site ZAN 02, Morogo bank reef, 6 miles W of Zanzibar town, OCDN 3563 -I (06°11.30’S, 039°07.70’E), depth 21 m, CRRF coll., 19 January 1996.   
 Etymology. The name is derived from the Latin angust (= narrow), referring to the relatively narrow body of the new species.   
 Description of female. Body (Fig. 146 A-C) eruciform, relatively narrow, unsegmented, curved dorsally; body length 1.05 mm; maximum width 316 μm (across second pedigerous somite). Posterior part of body from sec- ond pedigerous somite to genitoabdomen gradually narrowing in dorsal and ventral views. Cephalic shield about 175×250 μm, defined from first pedigerous somite only by lateral constrictions, lacking defined posterodorsal mar- gin. Dorsolateral tergal folds small on first pedigerous somite, but prominent in second to fourth pedigerous somites. Third and fourth pedigerous somites each with single, weak ventral interpodal protrusion. Genitoabdomen short, unsegmented; anal prominence (Fig. 146D) well-developed. Caudal ramus (Fig. 146D) tapering, unarmed, about 1.9 times longer than wide (73×38 μm).   
Rostrum absent. Antennule about 1.5 times longer than wide (51×35 μm), bulbous, with narrow proximal part; armed with 5 small setae on apex, longest seta 10 μm. Antenna (Fig. 146F) incompletely 2-segmented, about 2.1 times longer than wide (125×59 μm); proximal segment unarmed, slightly longer than distal segment; distal seg- ment ornamented with minute spinules on concave surface; armed with 6 setae, lengths of setae I-VI (medial to lateral) 18, 19, 14, 21, 22, and 29 μm, respectively; seta I weakly pinnate, positioned at 70% along medial margin of segment; setae II and III close to each other, both widely separated from seta IV.  
Labrum (Fig. 146G) with convex posterior margin and markedly inflated, bulbous palps. Mandible (Fig. 146G) tapering, much narrower than labral palp. Maxillule consisting of precoxa and palp; precoxa (Fig. 146H) with endite tipped with 1 spinulose seta and more than 30 thin, stiff setules; distal sclerotized part of precoxa weakly bifurcate, with 1 blunt tubercle and 1 patch of minute spinules near middle; palp (Fig. 146I) with 2+3 spines on distal margin and 1 naked seta on lateral margin. Maxilla (Fig. 146J) with bifurcate, spinulose process on endite of proximal segment; distal segment bearing spinulose subdistal process and 1 row of minute spinules on anterior surface; armed with 1 small seta proximally on posterior surface. Maxilliped absent.  
Legs 1-4 each with incompletely 2-segmented protopod and unsegmented rami (Figs. 146K, 147A, B); protopods unarmed. Exopods with proximal patch of spinules on lateral margin. Endopods 50×21, 54×26, 52×24, and 51×20 μm, respectively, in legs 1-4. Lengths of laterodistal and mediodistal setae 44 and 27, 44 and 25, 50 and 35, and 50 and 30 μm, respectively, in legs 1-4. Length ratios of laterodistal to mediodistal setae on endopods 1.63:1, 1.76:1, 1.43:1, and 1.67:1, respectively, in legs 1-4.  
Leg 5 (Fig. 147C) unarmed, obliquely wider than long (149×165 μm), with expanded dorsodistal corner.  
 Male. Unknown.   
 Remarks. The endopod of leg 1 of b. angustus sp. nov. carries a laterodistal seta which is distinctly shorter than the endopodal segment, but distinctly longer than the mediodistal seta. Seven species of bnterçcçla share these features with b. angustus sp. nov., as follows: b. parapterçphçrus, b. quadrẚsetus sp. nov., b. mabulensẚs sp. nov., b. dẚcaudatus, b. sydnẚẚ, b. rçbustus sp. nov., and b. parvus sp. nov.   
 The first three of these listed species can readily be distinguished by the presence of 4 or 5 setae on the antenna, compared with 6 setae in bK angustus sp. nov.. There are additional differences, such as the antennule of b. parapterçphçrus is armed with 3 or 4 setae (cf. 5 setae in the new species), the caudal rami of b. quadrẚsetus sp. nov. are about 3.2 times longer than wide (cf. 1.9 times), and leg 5 of b. mabulensẚs sp. nov. is oval (cf. obliquely wider than long, with expanded dorsodistal corner).   
 The remaining four congeners can be distinguished from b. angustus sp. nov. by the following features: in b. dẚcaudatus the cephalic shield bears a posterodorsal process, the caudal rami are elongate (about 3 times longer than wide), and the genitoabdomen bears a large ventral process (Marchenkov & Boxshall, 2005); in b. sydnẚẚ, the caudal rami are short (as long as wide), the antennule is armed with 7 setae, and the first to fourth pedigerous somites each bear a pair of ventral interpodal protrusions (Ooishi, 2011); in b. rçbustus sp. nov. the body is robust, the caudal rami are 3 times longer than wide, the antennule is armed with 3 setae, and the third and fourth pedigerous somites each bear a large interpodal protrusion on the ventral surface, and in b. parvus sp. nov. the body is small (560 μm long), the first and second pedigerous somites each bear a large dorsal tubercle, the antennule is armed with 3 setae, and the maxilla bears a spinulose tubercle proximally on the medial margin of the proximal segment.
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 pages 224-226, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/4820443