Botryllophilus dentirostris Kim & Boxshall 2021, sp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Cyclopoida
Ascidicolidae
Botryllophilus
Botryllophilus dentirostris

description: Botryllophilus dentirostris sp. nov.   
(Figs. 24-26)  
 Type material. Holotype ♀ (MNHN-IU-2018-1951), 4 ♀♀ paratypes (intact, MNHN-IU-2018-1952) and 2 ♀♀ paratypes (dissected, MNHN-IU-2014-17363) from budẚstçma clarum (Van Name, 1902) (MNHN-IT-2008-4031 = MNHN A3 / EUD/35); Guadeloupe Stn 13, West of l’îlet à Cochons, depth 5-10 m, Monniot coll., 23 December 1980.   
 Etymology. The specific name refers to the presence of rows of denticles on the ventral surface of the rostrum.   
 Description of female. Body (Fig. 24A, B) with broader anterior and narrower posterior parts, ventrally flexed between two parts. Body length 927 μm in figured specimen; maximum width 290 μm across second pedigerous somite. Anterior part slightly depressed, consisting of cephalosome and first to fifth pedigerous somites, with nearly parallel lateral margins; all somites of anterior part well-defined in dorsal view. Posterior part (Fig. 24C) slightly directed to left or right side, comprising genital somite and abdomen consisting of 8 annulations. Genital somite 110×184 μm, with convex lateral margins; genital areas located dorsally. Abdomen distinctly annulated; anterior 7 annulations much shorter than wide, 164 μm long in total; last annulation (anal somite) 73×82 μm. Caudal ramus (Fig. 24D) armed with 4 claws distally (2 larger inner and 2 smaller outer) and 1 dorsal seta and ornamented with 3 or 4 denticles (indicated by arrowhead in Fig. 24D) at outer proximal corner; one of outer claws blunt, with minute spinules at tip.   
Rostrum (Fig. 24E) rectangular, much wider than long, ornamented with oblique rows of 5 denticles ventrally on each side and with lobate tubercles posteromedially. Antennule (Fig. 24F) short and broad, distinctly 5-segment- ed; distal 3 segments much narrower than proximal 2 segments; armature formula 10 (5 large and 5 small), 4 (2 large and 2 small), 2 (1 large and 1 small), 4, and 7+aesthetasc; all setae naked. Right antenna (Fig. 24G) 4-segmented, consisting of coxa, basis, and 2-segmented endopod; coxa short and unarmed; basis longest segment, unarmed; first endopodal segment short and unarmed; second endopodal segment about 3.6 times longer than wide (64×18 μm), armed with 1 spine and 7 setae; proximal 2 inner setae naked; third inner element (spine) spinulose; innermost distal seta minute; 4 distal setae unequal in length, bearing spinules distally on inner margin. Left antenna with 2 outer distal setae slightly longer than those on right antenna.  
Labrum (Fig. 24H) subtriangular with well-sclerotized outer margins and soft ventral inflation bearing tapering lobe distally. Mandible (Fig. 24I) consisting of coxa and palp; medial margin of coxal gnathobase bearing 3 teeth distally (distalmost elongate with minute spinules along proximal margin) and finely spinulose proximally; palp unsegmented, with medial inflation near middle, armed with 3 outer setae (exopodal setae) proximally, 2 subdistal setae, and 4 distal setae; small, outer subdistal and outer distal seta naked, other setae pinnate. Maxillule (Fig. 24J) consisting of precoxa and palp; precoxa with 5 distinct setae and 1 minute seta on arthrite; palp consisting of coxobasis and endopod; coxobasis with 2 medial setae, 3 outer setae, 1 seta on epipodite, and 1 outer distal tubercle; endopod well-defined from coxobasis, with 3 setae distally. Maxilla (Fig. 25A) obscurely 2-segmented and armed with 10 setae (6 larger and 4 smaller). Maxilliped (Fig. 25B) 4-segmented; consisting of syncoxa, basis, and small, 2-segmented endopod bearing terminal claw; syncoxa broad, with 1 small seta on inner margin and 2 rows of fine spinules each on inner distal and outer middle surfaces; basis with 2 small setae subdistally and 1 row of fine spinules mediodistally; first endopodal segment unarmed; second endopodal segment with minute seta on inner margin; terminal claw slender, longer than segment and bearing 2 denticles on inner margin (1 proximally and 1 subdistally).  
Legs 1-4 (Figs. 25 C-F; 26A-D) biramous with 2-segmented rami; each leg asymmetrical between right and left members; coxae lacking inner element, but with row of minute spinules at mediodistal corner; basis with outer seta. Exopods of swimming legs spinulose along outer margins, mainly near bases of spines and setae; exopods of right swimming legs armed with spines, but endopods of right swimming legs and both rami of left swimming legs armed with setae. First endopodal segment of leg 1 with setulose tubercle on anterior surface. Second exopodal segment of left legs 3 and 4 elongated, hook-like (Fig. 26B, D), with pronounced subdistal process at base of third outer seta. One seta (inner subdistal seta) on second exopodal segment of left swimming legs vestigial. Numbers of spines (Roman numerals) and setae (Arabic numerals) on rami of legs 1-4 as follows:  
Leg 5 (Fig. 26E) tapering, approximately 210×100 μm, curved, with concave inner margin; armed with 4 naked setae (1 proximal, 1 subdistal, and 2 distal). Leg 6 (Fig. 26F) represented by 2 spinules and 1 setule in genital area.  
 Male. Unknown.   
 Remarks. Bçtryllçphẚlus dentẚrçstrẚs sp. nov. shares the same armature formula of legs 1-4 only with B. ruber. Both species also share an additional rare feature, i.e., the rami of all the swimming legs are 2-segmented (B. macrçpus is the only other species that shares this feature). Bçtryllçphẚlus ruber was fully redescribed by Ooishi (1999) and, unlike in that species, the second exopodal segment of left legs 3 and 4 of B. dentẚrçstrẚs sp. nov. is characteristically elongated and hook-like. In B. ruber, the rostrum is feeble, tapering, and lacks denticles (cf. rectangular and ornamented with rows of denticles in B. dentẚrçstrẚs sp. nov.), the maxilla is armed with 8 setae and 1 minute seta (cf. with 10 setae in B. dentẚrçstrẚs sp. nov.), the inner margin of the second endopodal segment of the antenna bears 3 spines (cf. 2 setae and 1 spine in B. dentẚrçstrẚs sp. nov.). These differences are sufficient to differentiate between these two species.
description: 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 48-52, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/4820443