Bonnierilla dinardensis, 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 : 275-278

Bonnierilla dinardensis sp. nov.

( Figs. 184 , 185 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21292 ) from Styela coriacea (Alder & Hancock, 1848) (MNHN-IT-2008-8221 = MNHNS1/STY/137), Les Richardais , Dinard, Atlantic coast of France, Monniot coll., August 1982 .

Etymology. This species is named after the type locality, Dinard, in France.

Descriptionoffemale. Body ( Fig. 184A ) stout, compressed; length 2.95 mm. Cephalosome clearly defined from metasome, with angular posterolateral corners on dorsal shield. Metasome inflated, unsegmented, with weak epimera near bases of legs 2 and 3. Freeurosome ( Fig. 184B ) 5-segmented: genitalsomite 55×300 μm, with minute copulatory pore near anterior border of ventral surface: 4 abdominal somites 165×310, 170×284, 116×247, and 116×203 μm, respectively. Caudalramus ( Fig. 184C ) slender, curved, narrowing distally, about 4.8 times longer than wide (278×58 μm) and about 2.4 times longer than anal somite: armed with 6 naked setae; 2 proximal setae located at 36 and 55% of ramus length.

Rostrum ( Fig. 184D ) flexible, lamellate, widerthan long and tapering steeply towards tip. Antennule ( Fig. 184E ) 8-segmented, bent at right angle between second and third segments; armatureformula 3, 15+spine, 8+aesthetasc, 4, 2+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; all setae naked. Antenna ( Fig. 184F ) slender, 4-segmented; coxa short; basis about 2.7 times longerthan wide, with 2 minute setal vestiges distally; firstendopodal segmentwith 1 seta subdistally; compound distal segment 3.9 times longer than wide (129×33 μm) and about 1.4 times longer than first; armed with 9 small setae plus strongly curved terminal claw, about half as long as second segment.

Labrum ( Fig. 184G ) with short, spinulose posteromedian lobe, patch of minute spinules subdistally on lateral margins, and setules on posterior margin. Mandible ( Fig. 184H ) with 5 teeth and 1 subsidiary tooth between distal first and second teeth on cutting margin of coxa; basis with proximal patch of setules and 1 distal setaonmedial margin; exopodwith 5 setae, distal 2 shorter than proximal 3; endopod incompleted articulated from basis, armed with 4 and 8 setae on first and second segments, respectively. Paragnath ( Fig. 184I ) with strong, claw-like apical process. Maxillule ( Fig. 184J ) as in B. quadridens sp. nov. Maxilla ( Fig. 185A ) with 3 setae and 1 minute setal vestige on first endite of syncoxa, otherwise with usual setation for genus. Maxilliped ( Fig. 184K ) incompletely 2-segmented; first segment with 10 setae, secondwith 2 unequal setae, longersetamorethan twice length of other seta.

Legs 1–4 ( Fig. 185 B-E) with 3-segmented rami. Inner coxal seta absent in legs 1 and 2, but well developed in legs 3 and 4. Outer seta on basis large, slightly shorter than exopod in leg 1, small inlegs 2 and 3, absentin leg 4. Inner distal spine on basis of leg 1 extending to middle of secondendopodal segment, 71 μm long, with serrate margins. Exopod 1.5 times longer than endopod in leg 1, about 2.l timeslongerinlegs 2 and 3, and 2.7 times longer in leg 4. Ratios of lengths of 3 exopodal segments 85:50: 55 inleg 2, 85:60: 65 inleg 3, and 85:65: 70 inleg 4. Second and third exopodal segments of leg 4 fringed with setules along outer margin; those of legs 1–3 naked or fringed with fine spinules. Armature formula for legs 1–4 as follows:

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

Leg 3	0-1	1-0	I-1; I-1; II, I, 5	0-1; 0-2; 1, 2, 3
Leg 4	0-1	0-0	I-1; I-1; II, I, 5	0-1; 0-2; 1, 2, 2

Leg 5 ( Fig. 185F ) with short protopod bearing outer distal seta and inner distal row of spinules; exopod elongate, about 4.8 times longerthan wide (218×45 μm), with 3 rows of fine spinules on inner surface; armed with 2 unequal setae distally, smaller distal seta on exopod of right leg 5 shorter than that on left leg 5.

Male. Unknown.

Remarks. Thediagnosticfeaturesof B. dinardensis sp. nov. include: the possession of only 5 setae (rather than 6) on the third endopodal segment of leg 1, the armature of the caudal ramus comprises only 6 setae (lacking any claw or spine), and the maxilliped bears a total of 12 setae. This combination of character states is shared with three congeners, B. altera , B. similis , and B. tenuipedis sp. nov. These congeneric species can be differentiated from B. dinardensis sp. nov. as follows: in B. altera the cephalosome has a “collar” (absent in B. dinardensis sp. nov.), the caudal ramus is about 4.1 times longer than wide (4.8 times in B. dinardensis sp. nov.), and the exopod of leg 5 is about 3.4 times longer than wide and armed with 1 seta distally (about 4.8 times and with 2 setae in B. dinardensis sp. nov.). In B. similis the antenna bears 3 large, digitiform setae distally (all setae small in B. dinardensis sp. nov.), the rostrum is elongate (wider than long in B. dinardensis sp. nov.), and the exopod of leg 5 is about 4 times as long as wide and armed with 1 seta distally (about 4.8 times and with 2 setaein B. dinardensis sp. nov.). In B. tenuipedis sp. nov. the rostrum is semicircular (tapering strongly towards tip in B. dinardensis sp. nov.), the compound distal endopodal segment of the antenna is short, not longer than first endopodal segment (1.4 times longer than first segment in B. dinardensis sp. nov.), and the third exopodal segment of legs 2–4 bears only 2 spines (3 spines in B. dinardensis sp. nov.).

Figures

FIGURE 184. Bonnierilla dinardensis sp. nov., female. A, habitus, right; B, urosome, ventral; C, caudal ramus; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, paragnath; J, maxillule; K, maxilliped. Scale bars: A, 0.1 mm; B, 0.1 mm; C–K, 0.05 mm.

FIGURE 185. Bonnierilla dinardensis sp. nov., female. A, maxilla; B, leg 1; C, leg 2; D, leg 3; E, leg 4; F, leg 5. Scale bars: 0.1 mm.