Botryllophilus bermudensis, 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 : 52-56

Botryllophilus bermudensis sp. nov.

( Figs. 27-29 )

Type material. Holotype ♀ (MNHN-IU-2018-1953), 2 ♀♀ paratypes (intact, MNHN-IU-2018-1954), and 2 ♀♀ paratypes (dissected, MNHN-IU-2014-17364) from aẚstaplẚa bermudensẚs Van Name, 1902; Bermuda, Monniot coll., March to May 1970.

Additional material. 1 ♀ (MNHN-IU-2018-1955), 1 ♀ (dissected, MNHN-IU-2014-17365) and 1 ♀ (MNHN- IU-2018-1956), all from a. bermudensẚs; Bermuda .

Etymology. The new species is named after the type locality, Bermuda.

Description of female. Body ( Fig. 27A, B ) stout, divisible into broader anterior and narrower posterior parts. Body length 1.04 mm; maximum width 382 μm. Anterior part consisting of cephalosome and first to fifth pediger- ous somites; each somite well-defined by dorsal and lateral constrictions; first to fourth pedigerous somites each bearing weak dorsal tergite. Posterior part of body comprising genital somite and abdomen consisting of 7 annulations ( Fig. 27C ). Genital somite 100×228 μm; genital apertures positioned dorsally. First to sixth abdominal annula- tions much shorter than wide; seventh (anal somite) 70×113 μm, ornamented with scattered fine spinules ventrally. Caudal ramus ( Fig. 27D ) about 1.7 times longer than wide, armed with 4 claws and 2 setae; outer distal claw bluntly tipped. Spermatophore ( Fig. 27E ) attached to female 140×52 μm, bulbous.

Rostrum absent but pair of comb-like membranes present on ventral surface of rostral area ( Fig. 27F ). Antennule ( Fig. 27G ) 172 μm long, 5-segmented; proximal 2 segments distinctly broadened; armature formula 10 (5 large and 5 small), 4 (3 large and 1 small), 2 (1 large and 1 small), 4, and 6+aesthetasc. Left antenna ( Fig. 27H ) 4-segmented; coxa, basis and first endopodal segment unarmed; second endopodal segment 3.2 times longer than wide (80×25 μm), armed with 6 setae and 1 spine (including 2 setae and 1 spine on inner margin). Right antenna differing slightly from left antenna in bearing 2 slightly shorter outer distal setae. All elements on antenna naked.

Labrum ( Fig. 27I ) simple, unornamented, consisting of thick-walled proximal part and thin-walled, convex distal part. Mandible ( Fig. 27J ) consisting of coxa and palp; coxa with 3 teeth on gnathobase, distal tooth spiniform, bearing minute spinules along proximal margin; palp elongate, armed with 9 setae arranged as 3, 2 (smaller one naked), 2 (including one naked), and 2; outer margin bearing small tubercle near base of proximalmost seta. Maxillule ( Fig. 28A ) consisting of precoxa and palp: precoxa with 5 distinct setae (second proximal seta bluntly tipped) and 1 minute seta on arthrite: palp 2-segmented; coxobasis with 2 setae on medial margin, 1 small seta on epipodite, 3 setae on outer margin, and 1 tubercle distally; endopod clearly defined from basis, with 3 setae on distal margin. Maxilla ( Fig. 28B ) obscurely 2-segmented, with 10 setae, including minute distal seta. Maxilliped ( Fig. 28C ) 4-segmented; first segment (syncoxa) broad, lacking seta, but with 1 inner, semicircular tubercle bearing row of minute spinules distally; second segment (basis) as long as wide, bearing 2 small setae subdistally and row of minute spinules at inner distal corner; third and fourth segments (first and second endopodal segments) small and unarmed; terminal claw small, bearing 2 minute denticles (proximal and subdistal) on concave inner margin.

Legs 1-4 ( Figs. 28 D-G, 29A-D) biramous, without inner seta on coxa; basis with outer seta and spinulose inner distal tubercle. Right and left leg 1 with 1-segmented exopod, but all rami of other swimming legs 2-segmented, although articulation incomplete between exopodal segments of left legs 2 and 3. Second exopodal segment of left legs bearing prominent tooth-like processes along outer margin; inner subdistal seta on this segment minute ( Figs. 28E, G , 29B, D ). Outer distal seta on second endopodal segment of legs 3 and 4 also minute. Numbers of spines (Roman numerals) and setae (Arabic numerals) on right and left legs 1-4 as follows:

Leg 5 ( Fig. 28H ) positioned dorsolaterally ( Fig. 27C ), about 2.6 times longer than wide, tapering, curved inwards, extending to middle of genital somite; armed with 4 setae (1 proximal, 1 subdistal, and 2 distal). Leg 6 represented by 2 small denticles on genital operculum.

Male. Unknown.

Remarks. The female of BK bermudensẚs sp. nov. possesses an abdomen consisting of 7 annulations and this feature is shared with four previously described species: B. aspẚnçsus, B. randallẚ Stock, 1970, B. cçnẚcus Conradi, López- González & García-Gómez, 1994, and B. symmetrẚcus Ooishi, 2014. The abdomen of BK ruber may be variable in apparent segmentation, exhibiting between 6 and 8 annulations ( Ooishi, 1999). Two of these five species, B. randallẚ and B. cçnẚcus, are known to have 7 armature elements on the terminal segment of the antenna ( Stock, 1970; Conradi et al., 1994), as in B. bermudensẚs sp. nov. They may be differentiated from the new species by the different setation of legs, because the right endopod of leg 2 of B. bermudensẚs sp. nov. is armed with 9 setae, compared to 7 in B. randallẚ and 8 in B. cçnẚcus, and the left endopod of leg 1 of B. bermudensẚs sp. nov. is armed with 8 setae, compared to 7 in B. randallẚ and B. cçnẚcus.

Figures

FIG. 27. Bçtryllçphẚlus bermudensẚs sp. nov., female. A, habitus, dorsal; B, habitus, right; C, posterior part of body from fifth pedigerous somite, dorsal; D, caudal ramus; E, spermatophore; F, rostral area; G, antennule; H, antenna; I, labrum; J, mandible. Scale bars: A-C, 0.1 mm; D, 0.02 mm; E-J, 0.05 mm.

FIG. 28. Bçtryllçphẚlus bermudensẚs sp. nov., female. A, maxillule; B, maxilla; C, maxilliped; D, right leg 1; E, left leg 1; F, right leg 2; G, left leg 2; H, leg 5. Scale bars: A, B, 0.02 mm; C-H, 0.05 mm.

FIG. 29. Bçtryllçphẚlus bermudensẚs sp. nov., female. A, right leg 3; B; left leg 3; C, right leg 4; D, left leg 4. Scale bars: 0.05 mm.