Botryllophilus longipes Kim & Boxshall 2021, sp. nov.

Botryllophilus longipes sp. nov. (Figs. 30-32) Type material. Holotype ♀ (MNHN-IU-2018-1957) and 1 ♀ paratype (dissected, MNHN-IU-2014-17366) from mçlyclẚnum saturnẚum Savigny, 1816 (MNHN-IT-2008-7031 = MNHN A1 / POL.B/24); Red Sea, Joussaume coll. Additional material. 1 ♀ (MNHN-IU-2014-17367, dissected) in mçlyclẚnum macrçphyllum Michaelsen, 1919; New Caledonia, outer Reef, Stn NC 24, depth 38 m, Monniot coll., 19 September 1985. Etymology. The name of the new species refers to its elongate leg 5. Description of female. Body (Fig. 30A) slender, symmetrical, divisible into broader anterior part comprising cephalosome and first to fifth pedigerous somites, and narrower posterior part comprising genital somite and 7 abdominal annulations (Fig. 30B). Body length 1.35 mm; width 335 μm across second pedigerous somite. Cephalo- some and first to fourth pedigerous somites defined only by weak constrictions and faint dorsal suture lines. Genital somite 76×164 μm; genital aperture positioned dorsally. Abdomen gradually narrowing posteriorly; 6 anterior ab- dominal annulations nearly equal in length, much wider than long; seventh (anal somite) 85×84 μm, bearing pair of large tubercles (indicated by arrowhead in Fig. 30C) posteroventrally. Caudal ramus (Fig. 30C) 37×29 μm, armed with 4 strong claws and 2 setae; claws pointed at tip and articulated at base. Rostrum as anterior process of cephalosome, with truncate anterior margin (Fig. 30A). Antennule (Fig. 30D) short, 5-segmented; first and second segments distinctly broader than distal segments, curved through right angle between first segment and remaining part; armature formula 10, 4, 3, 4, and 7+aesthetasc. Right antenna (Fig. 30E) 3-segmented, consisting of coxa, basis, and unsegmented endopod, but endopod bearing trace of articulation proximally on one surface; coxa and basis unarmed; endopod 71×23 μm, armed with 8 elements consisting of 2 slender proximal setae and 1 spinulose distal spine on inner margin, 1 small innermost distal spine, 2 inner distal spines, and 2 slender outer distal setae; all elements except distal spine on inner margin bluntly tipped; 4 outer distal elements bearing fine spinules distally. Left antenna different from right antenna in having 5 unornamented distal setae, of which 2 outer setae distinctly longer than those of right antenna. Labrum (Fig. 30F) strongly tapering, consisting of well-sclerotized proximal part and narrower, fleshy distal part. Mandible (Fig. 30G) bearing 2 teeth on coxal gnathobase and 8 setae on palp arranged as 3, 1, 2, and 2; 1 subdistal seta naked, all others pinnate. Maxillule (Fig. 30H) consisting of precoxa and palp; precoxa bearing 5 distinct setae and 1 minute seta on arthrite; palp consisting of coxa, basis, and endopod; coxa with small naked seta on epipodite; basis with 2 setae on medial margin (distal seta expanded at base), and 3 setae on outer margin; endopod incompletely articulated from basis, armed with 3 setae distally. Maxilla (Fig. 31A) obscurely segmented, armed with 8 setae; 5 medial setae bearing setules (or fine spinules) along their distal margin; 3 distal setae consisting of 2 smaller naked setae and 1 outer pinnate seta. Maxilliped (Fig. 30I) 4-segmented; syncoxa (first segment) unarmed but ornamented with 2 rows of spinules on outer side and 1 row of minute spinules on inner distal surface; basis tapering distally, bearing 2 small setae and 1 longitudinal row of spinules in distal region; first endopodal segment much wider than long, unarmed; second endopodal segment about 2.5 times longer than wide, bearing 1 small seta on inner margin and 1 tooth-like process at inner distal corner; terminal claw smooth, slightly shorter than second endopodal segment. Legs 1-4 (Figs. 31 B-G, 32A, B) biramous with 1-segmented exopods and 2-segmented endopods; coxa lacking inner seta; basis with small outer seta and row of minute spinules at inner distal corner. First endopodal segment of right legs 3 (Fig. 31F) and 4 (Fig. 32A) characteristically bearing elongate spine. Spines on rami of legs 1-4 usually bluntly tipped, with membranous cap at tip. Numbers of spines (Roman numerals) and setae (Arabic numerals) on right and left legs 1-4 as follows: Leg 5 (Fig. 32C) elongate, tapering, directed posterolaterally (Fig. 30A), about 3 times longer than wide (203×67 μm); armed with 4 setae; proximal and subdistal setae positioned at 22% and 75% of length of leg, respectively. Leg 6 (Fig. 32D) represented by 2 small spines and 1 dentiform process on genial operculum. Male. Unknown. Remarks. Two outstanding feature of B. lçngẚpes sp. nov. serve to differentiate it from all of its congeners: 1) the transformation of the seta on the first endopodal segment of right legs 3 and 4 into a spine, and 2) the presence of the pair of large ventrodistal tubercles on the anal somite. As additional diagnostic features of B. lçngẚpes sp. nov., the free abdomen comprises 7 well defined annulations and the antenna is armed with 8 setal elements. The latter combination of features is shared with B. aspẚnçsus, B. symmetrẚcus, and one variety of B. ruber. But B. lçngẚpes sp. nov. is readily distinguishable from these three congeners by the above-mentioned outstanding features and by having a different leg setation pattern; for example, the number of setae on the exopod of left leg 2 is 5, rather than 6 as in these three congeners.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 56-60, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/482044