Bonnierilla quadridens, 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 : 272-275

Bonnierilla quadridens sp. nov.

( Figs. 182 , 183 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21290 ) , paratype (intact ♀, MNHN-IU-2014-21291), anddissectedparatype (♀, figured) from Herdmania papietensis (Herdman, 1882) , LAGON DW1087, New Caledonia (19°48.3’S, 163°59.5’E), depth 24 m, B. Richer de Forges-IRD coll., 24 October 1989.

Additional material. 1 ♀ (dissected) from H. papietensis, Yaté , New Caledonia, 14 March 1987.

Etymology. The specific name refers to the four teeth on the tip of the caudal claw.

Descriptionoffemale.Body( Fig.182A )compressed, 3.37 mm long. Prosome 2.56 mm long, consisting of distinctly defined cephalosome and unsegmented metasome. Metsome typically with longitudinal furrow along dorsal midline. Fifth pedigerous somite fused to metasome.Freeurosome ( Fig.182B ) 5-segmented:genital somiteshort, 96×342 μm; 4 abdominalsomites 230×308, 200×265, 115×227, and 77×204 μm, respectively. Caudal ramus ( Fig. 182C ) slightly curved, narrowing distally, but produced into short conical process at ventrodistal corner; armed with 6 setae (2 near middle and 4 distal) plus 1 distal claw ( Fig. 182D ); distal claw 15 μm long, slightly curved with quadrifid apex; all setae naked and shorter than width of ramus; 2 middle setae located at 53 and 63% of ramus length.

Rostrum ( Fig. 182E ) semicircular, widerthan long. Antennule ( Fig. 182F ) small, 200 μmlong, 7-segmented; armatureformula 3, 16+spine, 8, 5, 4+aesthetasc, 2, and 8+2 aesthetascs; firstandsecondsegments expanded; setae crowded, naked and generally long. Antenna ( Fig. 182G ) with short coxa; basis with 2 small setal vestiges distally; firstendopodal segment with 1 subdistal seta; compound distal segment 4.0 times longerthan wide (100×25 μm) and 1.4 timeslongerthan first; armedwith 9 setae (distal 3 blunt at tip) plus terminal claw less than half length of segment.

Labrum ( Fig. 182H ) ornamented with patches of setules and spinules on posteroventral surface. Mandible ( Fig. 182I ) with 5 teeth on cutting margin of coxa; basis with proximal patch of small setules and 1 distal seta onmedial margin; exopodwith 5 setae, distal 2 slightly shorter than proximal 3; endopod with 4 and 9 setae on firstandsecondsegments, respectively. Maxillule ( Fig. 182K ) as usual for genus. Maxilla ( Fig. 183A ) typical for genus, armed with 3 setae on first endite of syncoxa and on third endopodal segment. Maxilliped ( Fig. 183B ) incompletely 2-segmented with 10 setae on first segment and 2 setaeon second.

Legs 1–4 with 3-segmented rami ( Fig. 183 C-E). Inner coxal seta absent in legs 1 and 2, but present in legs 3 and 4. Outer seta on basis large, distinctly longer than exopod, in leg 1, but very small in legs 2–4. Inner distal spine of basis of leg 1 spinulose on both margins, 53 μm long, extending beyond middle of second endopodal segment. Exopod 1.3 times longer than endopod in leg 1, and 1.5 times longer in legs 2–4. Exopodal segments of leg 1 densely setulose along outer margin. First exopodal segment of legs 2–4 about 2.5 times longerthan wide, and longer than second and third segments combined. First exopodal segment of leg 4 lacking inner seta. Inner setae on endopodal segments of legs 2–4 naked and small. Armature formula for legs 1–4 same as that of B. cheliphora sp. nov.:

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

Leg 5 ( Fig. 183F ) with short protopod bearing 1 small outer distal seta and inner distal row of minute spinules; exopod slender, about 5.1 times longer than wide (172×34 μm), with 1 minute seta and 1 larger seta distally (6 and 68 μm, respectively), ornamented with 5 rows of spinules on inner surface.

Male. Unknown.

Remarks. Bonnierilla quadridens sp. nov. has a claw on the caudal ramus, as in B. cheliphora sp. nov. and B. tahitiensis sp. nov., both described above. These three species are very alike in many other respects ( Table 4) and all of them were found in the South Pacific. They have a similar form and armature formula of legs 1–4, a similar shape of the caudal ramus and leg 5, and the same number of setae elements on mouthparts. One reliable character state that serves to differentiate between them is the armature of the caudal ramus: B. quadridens sp. nov. has 1 clawand 6 setae, B. cheliphora sp. nov. has 1 clawand 5 setae, and B. tahitiensis sp. nov. has 1 flagellate (setule-tipped) claw and 5 setae. The presence of 7 setation elements (6 setae plus an articulated claw) in B. quadridens sp. nov. is remarkable since the maximum number elsewhere in the family is 6.

Figures

FIGURE 182. Bonnierilla quadridens sp. nov., female. A, habitus, right; B, urosome, ventral; C, caudal ramus; D, distal part of caudal ramus; E, rostrum; F, antennule; G, antenna; H, labrum; I, mandible; J, paragnath; K, maxillule. Scale bars: A, 0.5 mm; B, 0.1 mm; C, E–I, J, 0.05 mm; D, 0.01 mm; J, 0.02 mm.

FIGURE 183. Bonnierilla quadridens sp. nov., female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5. Scale bars: 0.05 mm.