Enterocola robustus, 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 : 214-216

Enterocola robustus sp. nov.

( Figs. 138 , 139 )

Type material. Holotype ♀ (MNHN-IU-2014-21550), 1 ♀ paratype (MNHN-IU-2014-21551), and 1 ♀ paratype (dissected, MNHN-IU-2014-21484) from ieptçclẚnẚdes sp.;

Type locality. Maldives, N. Male atoll, 4km NW of Male I., OCDN 5247 -N (4°12.88´N, 73°29.27´E), depth 10 m, CRRF coll., 16 September 1997 .

Etymology. The specific name reflects the robust body.

Description of female. Body ( Fig. 138A, B ) robust, fleshy, curved dorsally; body length 623 μm; maximum width 292 μm (across second pedigerous somite). Cephalosome 131×196 μm, distinctly narrower than trunk, with distinct cephalic shield. First to fourth pedigerous somites defined from one another by lateral constrictions, each somite bearing pair of dorsolateral tergal folds, pair on first pedigerous somite indistinct. First and second pedigerous somites lacking ventral interpodal protrusion; third and fourth pedigerous somites each with single, broad interpodal protrusion ( Fig. 139B, C ). Genitoabdomen 4-segmented on ventral surface, but lacking traces of segmentation on dorsal surface; anal prominence distinct. Caudal ramus ( Fig. 138C ) unarmed, distinctly articulated from abdomen, about 3.0 times longer than wide (57×19 μm), slightly broadening distally, with rounded distal margin.

Rostrum absent. Antennule ( Fig. 138D ) unsegmented, about 1.5 times longer than wide (38×25 μm), widest in middle with convex posterior margin; armed with 3 setae on apex (anteriormost seta thick and bifurcate). Antenna ( Fig. 138E ) incompletely 2-segmented; shorter proximal segment unarmed; distal segment about 50×34 μm, orna- mented with patches of fine spinules on concave surface; armed with 6 setae (I-VI), lengths of setae 13, 9, 8, 8, 16, and 22 μm, respectively; medial seta (seta I) and lateral seta (seta VI) thicker than others.

Labrum ( Fig. 138F ) sub-circular with spinulose, bulbous palps. Mandible spinulose, narrower than labral palp. Maxillule ( Fig. 138G ) as usual for genus; endite of precoxa tipped with 1 spinulose seta and several spinules; palp with 5 spinulose spine on distal margin plus 1 naked, slender, spiniform seta on lateral margin. Maxilla ( Fig. 138H ) also as usual for genus; distal segment subdistally with 1 spinulose, basally articulated spine on anterior surface and 1 rudimentary seta proximally on posterior surface. Maxilliped absent.

Legs 1-4 biramous with incompletely 2-segmented protopods ( Fig.139 A-C); protopods unarmed. Exopods of legs 1, 2, and 4 tipped with small cusp; exopod of leg 3 acutely attenuated ( Fig. 139B ). Endopods incompletely 2-segmented, armed distally with 2 setae of unequal lengths. Sizes of endopods of legs 1, 3, and 4 (leg 2 pair missing) 46×22, 44×18, and 42×18 μm, respectively. Laterodistal and mediodistal setae on endopods unequal in length (former at least 1.27 times longer than latter), both shorter than endopodal segments, 31 and 24 μm in leg 1, 35 and 25 μm in leg 3, and 33 and 26 μm in leg 4.

Leg 5 ( Fig. 138I ) unarmed, obliquely wider than long (94×162 μm).

Male. Unknown.

Remarks. T he setation of the endopods of the swimming legs of bK rçbustus sp. nov. is unusual because: firstly, the laterodistal seta is longer than the mediodistal seta, and secondly, both setae are shorter than endopodal segment. This combination of character states is shared with only five known species, b. parapterçphçrus, b. mabulensẚs sp. nov., b. quadrẚsetus sp. nov., b. dẚcaudatus Marchenkov & Boxshall, 2005, and b. sydnẚẚ. The first three species can be eliminated from further comparison because they have fewer than 6 setae on the antenna (viz. 5 setae in b. parapterçphçrus and b. mabulensẚs sp. nov. and 4 setae in b. quadrẚsetus sp. nov.).

bnterçcçla sydnẚẚ is currently known from the Northeastern Atlantic and can be distinguished from b. rçbustus sp. nov. by its short caudal rami (which are approximately as long as wide), by the possession of 7 setae on the antennule, by having a slender labral palp, and by having paired interpodal protrusions on each of the first to fourth pedigerous somites ( Ooishi, 2011). bnterçcçla dẚcaudatus is known from Tanzania and differs from b. rçbustus sp. nov. in having an elongate antenna, a digitiform posteroventral process on the genitoabdomen, and a tapering process at the rear margin of the dorsal cephalic shield ( Marchenkov & Boxshall, 2005).

Figures

FIG. 138. bnterçcçla rçbustus sp. nov., female.A, habitus, dorsal; B, habitus. Right; C, caudal ramus; D, antennule; E, antenna; F, labrum; G, maxillule; H, maxilla; I, leg 5. Scale bars: A, B, 0.1 mm; C-H, 0.02 mm; I, 0.05 mm.

FIG. 139. bnterçcçla rçbustus sp. nov., female. A, leg 1; B, legs 3 and interpodal protrusion; C, legs 4 and interpodal protrusion, Scale bars: 0.02 mm.