Bonnierilla eurypodata Kim & Boxshall 2020, sp. nov.

Bonnierilla eurypodata sp. nov.

(Figs. 172, 173)

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21284) anddissectedparatype (♀, figured) from Polycarpa papillata (Sluiter, 1886), CORAIL 2, DW146, New Caledonia, Chesterfield Plateau (19°37’0.0012’’S, 158°16’16.7952’’E), depth 44 m, B. Richer de Forges-IRD coll., 30 July 1988.

Etymology. The specific name is derived from the Greek eury (=broad) and pod (=a foot) and refers to the relatively broad exopodal segment of leg 5.

Descriptionoffemale.Body(Fig.172A)compressed, inflated, 2.45 mm long. Cephalosome well-defined from metasome; metasomeunsegmented. Freeurosome (Fig. 172B) stout, 5-segmented. Caudal rami widely separated from each other; each ramus (Fig. 172C) fusiform, about 2.8 times longer than wide (110×40 μm) and about 1.3 times longer than anal somite, armed with 6 naked setae; 2 proximal setae as long as width of ramus, located at 40 and 64% of ramus length; distal 4 setae shorter than width of ramus.

Rostrum (Fig. 172D) widerthan long, strongly tapering, withrounded apex. Antennule (Fig. 172E) obscurely 8-segmented; armature formula 3, 15, 9+aesthetasc. 4, 3+aesthetasc, 1, 2+aesthetasc, and 7+aesthetasc; all setae naked; 1 seta on second segment rod-shaped. Antenna (Fig. 172F) 4-segmented; coxa unarmed; basis with 2 minute vestigial setae distally; first endopodal segment with 1 small seta subdistally; compound distal endopodal segment 3.1 times longer than wide and about 1.5 times longer than first endopodal segment, armed with 8 setae (distal 3 blunt at tip) plus strongly curved terminal claw, less than half length of segment.

Labrum (Fig. 172G) with patches of setules posterolaterally and spinules on posteromedian lobe. Mandible (Fig. 172H) bearing 5 teeth on coxal gnathobase and 3 needle-like spinules between distal second and third teeth; palp armed as usual: 1 seta on basis, 5 on exopod, 4 on first endopodal segment and 9 on second. Paragnath (Fig. 173A) with large dentiform process apically. Maxillule (Fig. 172I) not specialized, armedwith 9 setae on arthrite, 1 on coxal endite, 2 on coxal epipodite, 3 on basis, 4 each on exopod and endopod. Maxilla (Fig. 172J) 5-segmented; syncoxawith 8 setae (3, 1, 2, and 2); basis with claw bearing setules on both margins, plus 1 seta and 1 rudimentaryseta; endopodwith 1, 1, and 3 setaeonfirst to third segments, respectively. Maxilliped (Fig. 173B) incompletely 2-segmented with 10 setaeonfirst segment and 2 setaeon second.

Legs 1–4 (Fig. 173 C-F) with 3-segmented rami. Inner coxal seta absent in legs 1 and 2, but present in legs 3 and 4. Outer seta on basis large and plumose in leg 1 but small and naked in legs 2–4. Inner distal spine on basis of leg 1 naked, 49 μm long, extending beyond distal border of first endopodal segment. Exopods of legs 2–4 each about 1.8 times longerthan endopods. First and second exopodal segments of legs 2–4 lacking outer spines or with rudimentary spines. Third exopodal segment of legs 2–4 bearing only 2 spines; with inner setae naked. Third exopodal segment of leg 2 with 2 spines and 5 setae (armature formula I, I, 5) in holotype, but abnormally with 2 spines and 4 setae (armature formula I, I, 4; Fig. 173D) in dissected specimen. Armature formula for legs 1–4 as follows:

Leg 5 (Fig. 173G) 2-segmented; coxa short with naked outer distal seta and row of minute spinules at inner distal region; exopodal segment stout, about 2.3 times longerthan wide (173×76 μm) and abruptly narrowing in distal quarter; armed with naked apical seta; 4 rows of minute spinules present on inner margin.

Male. Unknown.

Remarks. Bonnierilla eurypodata sp. nov. is a typical form of Bonnierilla and is similar to B. iboensis sp. nov. and B. reniformis sp. nov., both described above. The most obvious differences between B. eurypodata sp. nov. and these other two species are in the dimensions of the caudal ramus and the exopod of leg 5 in the female. The caudal ramus of B. eurypodata sp. nov. is about 2.8 times longer than wide (110×40 μm) in contrast to 4.6 timeslongerthan wide (206×45 μm) in B. iboensis sp. nov. and 3.4 timeslongerthan wide (211×63 μm) in B. reniformis sp. nov. The exopod of leg 5 of B. eurypodata sp. nov. is 2.3 times longer than wide (173×76 μm), with a single apical seta, in contrast to 2.5 times longer than wide (136×55 μm) in B. iboensis sp. nov. and 2.7 times longerthanwide (203×74 μm) in B. reniformis sp. nov., with 2 unequal distal setae in the latter two species. These differences are robust and support the establishment of the new species.