Enterocola curticaudus, 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 : 239-241

Enterocola curticaudus sp. nov.

( Fig. 157 )

Type material. Holotype ♀ (MNHN-IU-2014-21566), 7 ♀♀ paratypes (MNHN-IU-2014-21567), and 2 ♀♀ para- types (dissected, MNHN-IU-2014-21479) from Trẚdẚdemnum sp.; Florida, United States of America, C. Young coll.

Etymology. The specific name of the new species is derived from Latin curt (=short) and caud (=the tail), referring to its short genitoabdomen.

Description of female. Body ( Fig. 157A, B ) eruciform, slightly curved dorsally; body length 633 μm; maximum width 275 μm (across second pedigerous somite). Cephalosome wider than long (120×200 μm), dorsally well-defined from trunk. Trunk unsegmented, with weak lateral constrictions between somites; third and fourth pedigerous somites with paired tergal folds dorsally. Ventral interpodal protrusions absent between left and right legs. Genitoabdomen ( Fig. 157C ) short, semicircular, unsegmented, wider than long, lacking anal prominence. Caudal rami not expressed, but pair of small caudal setae (setule-like and 22 μm long) present subdistally on lateral margins of genitoabdomen ( Fig. 157C ).

Rostrum absent. Antennule ( Fig. 157E ) obscurely 2-segmented, 60×28 μm, strongly tapering from broad proximal two-thirds towards narrow distal third; proximal segment with 2 small setae on posterior margin; distal segment narrow, about one-third as long as proximal segment, armed with 5 setae, distal seta larger than other setae, but not articulated from segment. Antenna ( Fig. 157F ) about 2.5 times longer than wide (100×40 μm), indistinctly 2-segmented; proximal segment unarmed; distal segment as long as proximal segment, and ornamented with several rows of minute spinules on concave surface; armed with 5 setae, lengths of setae 9, 16, 16, 28, and 33 μm, respectively; setae II and III positioned at mediodistal corner, and setae IV and V at laterodistal corner.

Labrum ( Fig. 157G ) with small patch of spinules near base of palp; palp inflated distally, bulbous. Mandible ( Fig. 157G ) rudimentary, reduced to small digitiform process, about one-third as long as labral palp. Maxillule as usual for genus; endite of precoxa tipped with 1 spinulose seta and numerous setules ( Fig. 157H ); palp ( Fig. 157I ) with 5 spines on distal margin and 1 seta on lateral margin. Maxilla ( Fig. 155J ) with unarticulated, spinulose mediodistal process on proximal segment; distal segment bluntly bifurcate and smooth distally, with 1 small seta on posterior surface. Maxilliped absent.

Legs 1-4 biramous, with unarmed, incompletely 2-segmented protopods ( Fig. 157 K-M). Exopods of legs 1-3 with patch of minute spinules proximally on lateral margin. Endopods 62×25, 57×25, 50×21, and 41×21 μm, respec- tively, in legs 1-4, incompletely 2-segmented in legs 1-3, but unsegmented in leg 4. Laterodistal and mediodistal setae distinctly shorter than endopodal segments, 41 and 29, 32 and 17, 22 and 15, and 18 and 6 μm, respectively, in legs 1-4, becoming shorter from anterior to posterior legs.

Leg 5 ( Fig. 157N ) unarmed, lamellate, wider than long (98×162 μm).

Male. Unknown.

Remarks. The absence of caudal rami is shared with only three known species of bnterçcçla, b. mçnnẚçtẚ, b. adnatus, and b. cçnẚculus but the new species can be easily differentiated from these congeners by the presence of a caudal seta, since all of these species lack caudal setae. There are additional differences: b. mçnnẚçtẚ has 6 setae on the antenna (cf. 5 setae in bK curtẚcaudus sp. nov.) and a 3-segmented endopod of leg 1 (cf. incompletely 2-segmented); b. adnatus has unsegmented endopods of legs 1-3 (cf. incompletely 2-segmented); and b. cçnẚculus has 2 setae on the antennule (cf. 5 in b. curtẚcaudus sp. nov.) and 6 setae on the antenna (cf. 5 setae). These differences are sufficient to distinguish the new species. The mandible of b. curtẚcaudus sp. nov. is rudimentary, which is an unusual feature within the genus.

Figures

FIG. 157. bnterçcçla curtẚcaudus sp. nov., female.A, habitus, dorsal; B, habitus, right; C, genitoabdomen, right; D, egg sac; E, antennule; F, antenna; G, labrum and mandibles; H, precoxa of maxillule; I, palp of maxillule; J, maxilla; K, leg 1; L, leg 3; M, leg 4; N, leg 5. Scale bars: A, B, D, 0.1 mm; C, N, 0.05 mm; E-M, 0.02 mm.

FIG. 155. bnterçcçla çlẚgçsetçsus sp. nov., female. A, habitus, dorsal; B, habitus, ventral; C, habitus, right; D, genitoabdomen, ventral; E, left caudal ramus, lateral; F, antennule; G, antenna; H, labrum and mandibles; I, maxilla; J, leg 5. Scale bars: A-C, 0.1 mm; D, J, 0.05 mm; E-I, 0.02 mm.