Bonnierilla reniformis, Kim & Boxshall, 2020

Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), Megataxa 4 (1), pp. 1-6 : 254-258

Bonnierilla reniformis sp. nov.

( Figs. 170 , 171 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21283 ) from Styela canopus (Savigny, 1816) (MNHN-IT-2008-XXXX = MNHNS1/ STY/316), ATIMOVATAE TR16, Madagascar (24°59 Ś, 47°05 É), depth 15-17 m, MNHN coll., 09 May 2010.

Etymology. The specific name is derived from the Latin ren, meaning kidney, and refers to kidney-shaped body of the new species, as is typical in the genus Bonnierilla .

Descriptionoffemale. Body ( Fig. 170A ) stout, compressed; length 3.46 mm. Prosome inflated, 2.84 mm long, consisting of well-defined cephalosome and unsegmented metasome. Freeurosome ( Fig. 170B ) 5-segmented, narrowing posteriorly: genitalsomite short, obscurely defined from metasome; 4 abdominal somites 254×335, 154×285, 96×238, and 104×223 μm, respectively. Caudal rami widely separated from each other; each ramus ( Fig. 170C ) about 3.4 times longer than wide (211×63 μm) and twice as long as anal somite, widest at proximal quarter, with straight outer margin and proximally convex inner margin: armed with 6 naked setae, all shorter than width of ramus; outer lateral and dorsal setae located at 37 and 62% of ramus length, respectively.

Rostrum ( Fig. 170D ) widerthan long, 144×152 μm, tapering slightly proximally and strongly distally. Antennule ( Fig. 170E ) 403 μm long, 6-segmented; terminal segment with traces of 2 articulations; first and second segments broad; armature formula 3, 16, 9+aesthetasc, 4, 2+aesthetasc, and 11+aesthetasc; setae mostly small, all naked. Antenna ( Fig. 170F ) slender, 4- segmented; coxa short and unarmed; basis about 2.6 times longerthan wide and armed with 2 minute vestigial setae distally; first endopodal segment slightly longer than wide, with convex outer margin, armed with 1 small seta subdistally; compound distal endopodal segment about 3.6 times longer than wide (115×32 μm); armed with 9 small setae plus strongly curved terminal claw, about half as long ent.

Labrum ( Fig. 171A ) setulose posteriorly and with weakly pronounced, spinulose posteromedian lobe. Mandible ( Fig. 170G ) bearing 3 teeth and 1 small setaon coxalgnathobase; basiswith 1 medial seta; exopodwith 5 setae, outer distal seta about half as long as other 4; endopod with 4 and 9 setaeon first and second segments, respectively. Maxillule ( Fig. 170H ) with 9 setaeon arthrite, 1 broad seta on coxal endite, 2 on epipodite, 3 on basis (proximal seta about one-third as long as distal 2), and 3 each on exopod and endopod. Maxilla ( Fig. 170I ) armedwith 3, 1, 2, and 3 setaeon first to fourth endites of syncoxa, basis with claw plus 1 seta; and 1, 1, and 3 setae on first to third endopodal segments, respectively. Maxilliped ( Fig. 171B ) unsegmented, but divisible into broad proximal and narrow distal parts bearing 10 and 2 setae, respectively.

Legs 1–4 ( Figs. 171 C-F) with 3-segmented rami. Inner seta on coxa absent in legs 1 and 2, but present in legs 3 and 4. Outer setaon basis well-developed (shorter than exopod) in leg 1, but small in legs 2–4. Inner distal spineonbasisofleg 1 naked, 77 μmlong, extending beyond middle of second endopodal segment. Exopod about 1.7 timeslongerthan endopod inleg 2, about 1.8 times longer in leg 3, and twice as long in leg 4. Outer spines on exopodal segments of legs 2–4 vestigial or absent. All inner setae on third exopodal segment of legs 2–4 naked. Armature formula for legs 1–4 as follows:

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-I	I-1; I-I; III, I, 4	0-1; 0-1; 1, 2, 3
Leg 2	0-0	1-0	I-1; I-1; I, I, 5	0-1; 0-2; 1, 2, 3
Leg 3	0-1	1-0	I-1; 0-1; I, I, 5	0-1; 0-2; 1, 2, 3
Leg 4	0-1	1-0	0-1; 0-1; I, I, 5	0-1; 0-2; 1, 2, 2

Leg 5 ( Fig. 171G ) very similar to that of B. iboensis sp. nov.; exopodal segment about 2.7 times longerthan wide (203×74 μm), armed with 2 unequal setae distally; segment with 4 rows of minute spinules on inner margin.

Male. Unknown.

Remarks. Bonnierilla reniformis sp. nov. is very similar to B. iboensis sp. nov. They were found associated with the same species of ascidian host in nearby geographic regions and their appendages, including the characteristic exopod of leg 5, are very alike. However, the differences between these two species in the caudal ramus and rostrum are significant. The caudal ramus of B. reniformis sp. nov. is significantly broader than that of B. iboensis sp. nov., about 3.4 timeslongerthan wide (vs. 4.6 times longer than wide in B. iboensis sp. nov.), and the rostrum is wider than long (vs. longer than wide in B. iboensis sp. nov.).

Figures

FIGURE 170. Bonnierilla reniformis sp. nov., female. A, habitus, right; B, urosome, ventral; C, caudal ramus; D, rostrum; E, antennule; F, antenna; G, mandible; H, maxillule; I, maxilla. Scale bars: A, 0.5 mm; B, 0.1 mm; C-I, 0.05 mm.

FIGURE 171. Bonnierilla reniformis sp. nov., female. A, labrum; B, maxilliped; C, leg 1; D, leg 2; E, leg 3; F, leg 4; G, leg 5. Scale bars: A, B, 0.05 mm; C-G, 0.1 mm.