Enterocola sulcatus, Kim & Boxshall, 2021

Kim, Il-Hoi & Boxshall, Geoff A., 2021, Copepods (Cyclopoida) associated with ascidian hosts: Ascidicolidae, Buproridae, Botryllophilidae, and Enteropsidae, with descriptions of 84 new species, Zootaxa 1, pp. 1-286 : 229-232

publication ID	https://doi.org/ 10.11646/zootaxa.4978.1.1
publication LSID	lsid:zoobank.org:pub:9C7C1723-73EB-4FBE-A47A-54627DEB8F93
DOI	https://doi.org/10.5281/zenodo.10530963
persistent identifier	https://treatment.plazi.org/id/3729879B-FF01-FF10-FA93-FC3DD0161CFB
treatment provided by	Plazi
scientific name	Enterocola sulcatus
status	sp. nov.

Treatment

Enterocola sulcatus sp. nov.

( Figs. 150 View FIG , 151 View FIG )

Type material. Holotype ♀ (MNHN-IU-2014-21559) and 1 ♀ paratype (dissected, MNHN-IU-2014-21476) from Apl ẚdẚum nadaense (Nishikawa, 1980) (MNHN-IT-2008-576 = MNHN A1 View Materials / APL.B/407); Papua New Guinea, Louisiades Archipelago , Calvados Islands , Channel E of Brooker I., Site Brooker Channel, OCDN 5743 -A, (11°03.09’S, 152°28.62’E), depth 7 m, CRRF coll., 01 June 1998. GoogleMaps

Etymology. The name is derived from the Latin sulc (=a furrow), alluding to the presence of a longitudinal furrow on the endopods of legs 1-4.

Description of female. Body ( Fig. 150 View FIG A-C) eruciform, consisting of cephalosome, trunk, and genitoabdomen. Body length 1.24 mm; maximum width 373 μm (across fourth pedigerous somite). Cephalic shield distinctly narrower than trunk (177×223 μm), with distinct posterior margin. Trunk gradually broadening posteriorly, unseg- mented; first to fourth pedigerous somites each bearing dorsal tergite; first pedigerous somite completely covered by tergite, but second to fourth pedigerous somites partly covered by tergite; tergites on second and third pedigerous somites with incomplete posterior margin, thus forming dorsolateral tergal folds. First to fourth pedigerous somites each bearing pair of ventral interpodal protrusions between left and right legs; each protrusion tipped with nippleshaped knob ( Fig. 150B View FIG , 151 View FIG A-D). Genitoabdomen ( Fig. 150D View FIG ) directed slightly posteroventrally ( Fig. 150C View FIG ), dorsally unsegmented, but ventrally 4-segmented; anal prominence large. Caudal rami ( Fig. 150E View FIG ) tapering, 1.75 times longer than wide (63×36 μm), with straight lateral margin, convex medial margin, blunt apex; armed with 1 small seta (19 μm long) subdistally on medial margin. Egg sac containing 6 to 8 eggs in 2 rows; each egg relatively large, about 160 μm in diameter.

Rostrum absent. Antennule ( Fig. 150G View FIG ) about 58×45 μm, obscurely 2-segmented; proximal segment broad, armed with 4 setae (2 on convex posterior margin and 2 distally); distal segment shorter and much narrower than proximal segment, armed with 3 setae (2 on posterior margin and 1 on apex). Antenna ( Fig. 150H View FIG ) unsegmented, lacking any trace of articulation, approximately 89×41 μm, armed with 6 naked setae (1 on medial margin, 2 on lateral margin and 3 on distal margin); setae II-VI longer than width of segment; lengths of setae I-VI 16, 45, 45, 54, 61, and 75 μm, respectively.

Labrum ( Fig. 150I View FIG ) with patches of spinules on ventral surface; palp densely spinulose, gradually broadening distally. Mandible ( Fig. 150J View FIG ) tapering, spinulose, distinctly narrower than labral palp. Maxillular precoxa ( Fig. 150K View FIG ) with excavated apex, 2 processes subdistally, and endite in middle tipped with 1 spinulose spine and about 15 stiff setules; palp ( Fig. 150L View FIG ) armed with 6 thick spines, 5 on distal margin and 1 on lateral margin. Maxilla ( Fig. 150M View FIG ) 2-segmented; proximal segment bearing 1 small tubercle proximally on medial margin and 1 spinulose, basally articulated element on mediodistal endite; distal segment bifurcate and spinulose distally, with 1 small seta on posterior surface. Maxilliped absent.

Legs 1-4 ( Fig. 151 View FIG A-D) each consisting of coxa, basis, and unsegmented rami; coxae unarmed; basis characteristically bearing digitiform laterodistal process tipped with minute seta. Exopods of legs 2-4 bearing patch of spinules proximally on lateral margin. Endopods marked by longitudinal furrow along lateral surface, receiving tip of exopods. Sizes of endopods 46×26, 52×26, 48×27, and 46×27 μm, respectively, in legs 1-4. Laterodistal and mediodistal setae distinctly longer than endopodal segments, setal lengths 94 and 85, 105 and 81, 94 and 81, and 101 and 87 μm, respectively, in legs 1-4. Laterodistal setae 1.1, 1.3, 1.2, and 1.2 times longer than mediodistal setae, respectively, in legs 1-4.

Leg 5 ( Fig. 151E View FIG ) more than twice as wide as long (90×188 μm), bearing 2 small setae on distal margin, sepa- rated by distance of 125 μm.

Male. Unknown.

Remarks. bnterçcçla sulcatus sp. nov. can be recognized by the following outstanding features: (1) the paired ventral interpodal protrusions on the first to fourth pedigerous somites are tipped with a nipple-shaped knob; (2) in legs 1-4, the basis bears a digitiform laterodistal process; and (3) the endopods of legs 1-4 each bear a longitudinal furrow along the lateral surface. These three features are as yet unknown elsewhere in bnterçcçla and, therefore, serve to characterize the new species.

An additional diagnostic feature of b. sulcatus sp. nov. is the armature of a single seta on the caudal rami. This feature is shared with three other known species, b. ẚnathẚnus, b. latẚceps, and b. setẚcaudus sp. nov. Of these, b. setẚcaudus sp. nov. is the most similar to b. sulcatus sp. nov. in sharing the same basic body form and the setation patterns of the antennule, antenna, and swimming legs. However, none of these congeners exhibits any of the three features highlighted above. We also note that b. setẚcaudus sp. nov. differs from b. sulcatus sp. nov. in other morphological details, for example, the caudal seta is positioned at apex of the caudal ramus, and the mediodistal process of first maxillary segment is bifurcate unlike that of b. sulcatus sp. nov.