Enterocolides pacificus, 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 : 244-246

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.4822601
persistent identifier	https://treatment.plazi.org/id/3729879B-FF16-FF02-FA93-FE15D7E01B1E
treatment provided by	Plazi
scientific name	Enterocolides pacificus
status	sp. nov.

Treatment

Enterocolides pacificus sp. nov.

( Figs. 160-162 View FIG View FIG View FIG )

Type material. Holotype ♀ (MNHN-IU-2014-21569), 3 ♀♀ paratypes (MNHN-IU-2014-21570) and 1 ♀ paratype (dissected, MNHN-IU-2014-21480) from ieptçclẚnẚdes sp. (MNHN-IT-2008-4853 = MNHN A2 About MNHN / LEP/95 ); Papua New Guinea, SE Normanby Is., Cape Prevost, CRCHO 501 , Site PREVOST 2 (12°06.33´S, 150°57.68´E), depth 49 m, CRRF coll., 20 January 2002. GoogleMaps

Additional non-type material. 11 ♀♀ (MNHN-IU-2014-21571, 2 ♀♀ dissected) from Atr ẚçlum marsupẚalẚs Monniot F., 1989 (MNHN-IT-2008-1347 = MNHN A2 About MNHN / ATR/1 ); New Caledonia, Grande Terre, Ilot Maitre, près de la balise, Stn NC 14, depth 6-9 m, Monniot coll., 11 September 1985 ; 7 ♀♀ (MNHN-IU-2014-21572, 1 ♀ dissected) from Tr ẚdẚdemnum sp.; Papua New Guinea, CRCHO 491 , Site DUCHEDD IS, off W Normanby I. (09°57.82´S, 150°50.73´E), depth 10 m, CRRF coll., 19 January 2002 GoogleMaps .

Etymology. The name of the new species reflects its distribution (Pacific Ocean), in contrast to the Mediterranean distribution of the type species.

Description of female. Body ( Fig. 160A, B View FIG ) cylindrical, unsegmented, curved dorsally. Body length 800 μm; maximum width 315 μm (across second pedigerous somite). Cephalic shield 167×256 μm, slightly narrower than trunk, with incomplete posterior margin. Trunk unsegmented; first to fourth pedigerous somites each bearing large, lamellate tergal folds dorsolaterally. Genitoabdomen ( Fig. 160C View FIG ) short, dorsoventrally deeper than laterally wide, unsegmented, with 2 or 3 faint wrinkles laterally; anal prominence large. Caudal rami and caudal setae absent. Egg sac ( Fig. 160D View FIG ) containing 4- 6 eggs; each egg about 167 μm in diameter.

Rostrum absent. Antennule ( Fig. 160E View FIG ) elongate, unsegmented, about 2.3 times longer than wide (70×30 μm), tapering in distal half; armed with 8 small setae, 4 subdistally and 4 on apex. Antenna ( Fig. 160F View FIG ) about 2.0 times longer than wide (127×63 μm), 2-segmented; proximal segment unarmed, but ornamented with posterodistal patch of minute spinules; distal segment narrowing distally, armed with 4 setae (setae II-V) at apex, 1 larger than others; setae I and VI reduced to setule-like vestiges separated from large setae.

Labrum ( Fig. 160G View FIG ) with narrow, spinulose palps. Mandible spinulose, tapering, slightly broader than labral palp. Maxillule consisting of precoxa ( Fig. 160H View FIG ) and palp ( Fig. 160I View FIG ); precoxa bluntly trilobed distally, with endite bearing 1 naked seta and tuft of numerous thin setules; palp with 5 spinulose spines (or spiniform setae) on distal margin and 1 minute vestigial seta on lateral margin. Maxilla ( Fig. 160J View FIG ) 2-segmented; proximal segment with large, spinulose process mediodistally; distal segment unequally bifurcate, unarmed and unornamented. Maxilliped absent.

Legs 1-4 each consisting of 2-segmented, unarmed protopod and unsegmented rami ( Fig. 161 View FIG A-C). Exopods of legs 1, 2, and 4 small, much shorter than endopods, unarmed, triangular, pointed distally; exopod of legs 3 attenuated, with acutely pointed tip. Endopods of legs 1 and 2 twice as long as wide, armed with 2 naked setae distally; laterodistal seta 0.7 times as long as endopodal segment, but slightly longer than mediodistal seta. Endopods of legs 3 and 4 unarmed, slightly longer than wide, with rounded distal margin.

Leg 5 ( Fig. 160K View FIG ) lamellate, unarmed, wider than long (130×196 μm).

Comparative description of female associated with Atiolum marsupialis in New Caledonia ( Fig. 162 View FIG ). Body ( Fig. 162A, B View FIG ) inflated, fleshy; body length 1.03 mm in dissected specimen; mean body length 0.96 mm (0.82-1.11 mm, n=8); maximum width 441 μm (across second pedigerous somite). Cephalic shield much narrower than trunk, with obscure dorsal margin. Dorsolateral tergal folds less developed than those of type specimens. Egg sac containing more than 30 eggs; each egg about 140 μm in diameter, smaller than in type specimens.

Antennule ( Fig. 162C View FIG ) more slender than that of type specimens, armed with 8 small setae. Antenna ( Fig. 162D View FIG ) as that of type specimens in form and armature, but relative lengths of setae slightly different. Labrum ( Fig. 162F View FIG ) ornamented with several patches of spinules on ventral surface. Mandible ( Fig. 162F View FIG ), maxillule ( Fig. 162G, H View FIG ), and maxilla ( Fig. 162I View FIG ) as in type specimens.

Legs 1-4 with same form and setation as in type specimens, but distal setae on endopods of legs 1 and 2 slightly longer and weakly pinnate. Leg 5 ( Fig. 162M View FIG ) 110×204 μm.

Male. Unknown.

Remarks. As illustrated, the type specimens from Papua New Guinea and additional material from New Caledonia exhibit some differences in body form, in the development of the dorsolateral tergal folds on the trunk, the relative lengths of the setae on the antenna and legs 1 and 2, and in the size of the eggs. However, we infer that these differences represent infraspecific variation.

The presence of 2 setae on the endopods of legs 1 and 2 of b. pacẚfẚcus sp. nov. is the most marked difference from the type species, b. ecaudatus, which lacks endopodal setae on all legs. Other differences include: the presence of well-developed dorsolateral tergal folds on the first to fourth pedigerous somites (cf. these tergal folds lacking in b. ecaudatus), the antennule is armed with 8 setae (cf. 2 setae and several spinules in b. ecaudatus, according to illustration in Illg & Dudley, 1980), the antenna is 2-segmented and armed with 4 naked setae plus 2 setule-like vestiges (cf. unsegmented and armed with 6 spinulose setae in b. ecaudatus), the distal margin of the maxillular palp is armed with 5 setae (cf. 4 setae in b. ecaudatus), the lateral margin of the exopods of legs 1, 2, and 4 is smooth (cf. ornamented with a cusp and spinules in b. ecaudatus), the distal segment of the maxilla is distally bifurcate and lacks a proximal seta (cf. simple, but with a proximal seta in b. ecaudatus), and leg 5 is wider than long and unarmed (cf. longer than wide and armed with a pair of small setae in b. ecaudatus).