Bonnierilla altera Stock, 1967

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 : 242-245

Bonnierilla altera Stock, 1967

( Figs. 161 , 162 )

Syn: Bonnierilla longipes: Canu, 1892: 197 , pl. 9, fig. 4- 13, pl. 10, fig. 1.

Material examined. 1 ♀ (MNHN-IU-2018-1839) and 1 dissected ♀ (figured) from Polycarpa pomaria (Savigny, 1816) , Portugal.

Description of female. Body ( Fig. 161A ) compressed, 3.90 mmlong. Prosome 3.32 mmlong, consistingof well-defined cephalosome and inflated, unsegmented metasome. Posterior border of cephalosome extended to form sculptured flared “collar” overlapping anterior part of metasome; posterolateral corners of dorsal shield produced into blunt processes ( Fig. 161A, B ). Free urosome small and 5-segmented. Caudal ramus ( Fig. 161C ) curved ventrally and gradually narrowing distally, about 4.1 timeslongerthan wide (261×63 μm); armed with 6 small, naked setae; outer lateral and dorsal setae positioned at 43 and 62% of ramus length, respectively; all setae shorter than width of ramus at base.

Rostrum ( Fig. 161D ) aslongas wide, tapering steeply.Antennule ( Fig. 161E ) 380 μmlong, 8-segmented; firstandsecondsegments expanded; armatureformula 3, 16, 8+aesthetasc, 4, 2+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; all setae naked and thin. Antenna ( Fig. 161F ) slender, 4-segmented; shortcoxa unarmed; basis about 2.7 times longerthan wide, with small tubercle at outer distal corner tipped with vestigial exopodal seta; first endopodal segment about 1.4 times longer than wide, with 1 smallseta subdistally; compounddistalendopodal segment 3.8 timeslongerthan wide (141×37 μm), armed with 7 smallsetae (distal 3 blunt tipped) plusterminal claw about half as long as segment.

Labrum ( Fig. 161G ) with setules on posterior margin and spinules on posteromedian lobe. Mandible ( Fig. 161H ) with 5 teeth on coxal gnathobase; basis with 1 distal seta plus proximal tuft of setules on medial margin; exopod with 5 setae, distal 2 distinctly shorter than other 3; endopod incompletely articulated at base and between segments, armed with 4 and 8 setae on first and second segments, respectively; distalmost seta on first endopodal segment naked and proximalmost seta on second endopodal segment minute, spinule-like. Paragnath ( Fig. 161I ) with strongly curved, claw-like apical process. Maxillule ( Fig. 161J ) armedwith 10 setaeon arthrite, 1 broad seta on coxal endite, 2 unequal setae on epipodite, 3 on basis (proximal seta much smaller than distal 2), 4 each on exopod and endopod. Maxilla ( Fig. 161K ) 5- segmented; syncoxawith 9 setae (3, 1, 2, and 3); basiswith smooth clawplus 1 large and 1 minute seta; endopod with 1, 1, and 3 setae on first to third segments, respectively. Maxilliped ( Fig. 162A ) incompletely 2-segmentedwith 10 and 2 setae on first and second segments, respectively; setae on second segment unequal, smaller seta less than half as long as large seta.

Legs 1–4 ( Fig. 162 B-E) with 3-segmented rami. Inner coxal seta absent in legs 1 and 2, but large seta present in legs 3 and 4. Outersetaonbasis large, slightlylonger than exopod in leg 1, but small and naked in legs 2–4. Exopod about 1.4 times longer than endopod in leg 1 and more than twice as long in legs 2–4. Spines on exopods of legs 2–4 small and blunt at tip. Third exopodal segment of legs 2–4 tapering, slightly longerthan second. 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; III, 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	1-0	I-1; I-1; II, I, 5	0-1; 0-2; 1, 2, 2

Leg 5 ( Fig. 162F ) protopod bearing small, naked outer distal seta, lacking spinules on posterior border; exopodal segment digitiform and about 3.4 times longer than wide (235×69 μm), armed with 1 naked seta distally and ornamented with 5 rows of fine spinules on inner surface.

Male. Unknown

Remarks. The two females available in this study can be identified as B. longipes sensu Canu (1892) , which was renamed by Stock (1967) as B. altera . Ourspecimens generally agree with Canu’s illustrations in having similar body size, the flared “collar” of the dorsal shield covering the cephalosome, two very unequal setae on the second segment of the maxilliped, 5 setae on the third endopodal segment of leg 1, and the same shape of exopodal segment of leg 5. Canu mentioned that this copepod was very common in “ Cynthia lurida ” (the current valid name of this ascidian is not confirmable in WoRMS) at Boulogne on the coast of France and co-occurred together with Gunenotophorus globularis , Doropygus pulex Thorell, 1859 and Lichomolgusalbens Thorell, 1859 . Interestingly, B. altera , G. globularis , and D. pulex all co-occurred in the ascidian Polycarpa pomaria in this study.

Figures

FIGURE 161. Bonnierilla altera Stock, 1967, female. A, habitus; B, right posterolateral corner of cephalosome; C, caudal ramus; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, paragnath; J, maxillule; K, maxilla. Scale bars: A, 0.5 mm; B, D, H, 0.l mm; C, E-G, I-K, 0.05 mm.

FIGURE 162. Bonnierilla altera Stock, 1967, female. A, maxilliped; B, leg 1; C, leg 2; D, leg 3; E, leg 4; F, leg 5. Scale bars: 0.1 mm.