Doropygella corsensis, 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 : 310

Doropygella corsensis n. sp.

( Figs. 207 , 208 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21305 ) from Phallusia fumigata (Grube, 1864) (MNHN-IT-2008-6126 = MNHN P5/ PHA/49), Solenzara, Corsica, France, Monniot coll., 1982.

Etymology. The new species is named after Corse, the French name for Corsica, the type locality.

Descriptionoffemale. Body ( Fig. 207A ) slightly dorsoventrally depressed, 2.68 mm long. Prosome consisting of cephalosome and obscurely segmented metasome, with pedigerous somites defined only by weak dorsal and lateral constrictions. Second and third pedigerous somites with weakly defined epimera; fourth pedigerous somite forming strongly inflated, bulbous brood pouch, slightlylonger than wide and slightly longer than anterior part of prosome. Free urosome ( Fig. 207B ) distinctly 5-segmented; genital somite much wider than long, 85×273 μm; 4 abdominalsomites 173×227, 167×200, 94×170, and 100×215 μm, respectively. Caudal ramus ( Fig. 207C ) slender, about 5.3 timeslongerthan wide (190×36 μm) and 1.9 times longer than anal somite: armed with 2 small setae and 4 small, distal spines; 2 setae located at 22 and 62% of ramus length; 4 distal spines claw-like, at most 12 μm long, less than distal width of ramus.

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

Rostrum ( Fig. 207D ) as long as wide, tapering from broad base towards rounded apex. Antennule ( Fig. 207E ) slender, 198 μm long, 9-segmented; first and second segments broadened; armatureformula 3, 15+2 spines, 6, 4+aesthetasc, 2, 4, 3+aesthetasc, 2, 9+aesthetasc; 2 large setae on first segment pinnate, all other setae naked. Antenna ( Fig. 207F ) slender, 4-segmented; coxa unarmed; basisalso unarmed, 2.7 timeslongerthan wide; first endopodal segment with 1 seta subdistally, twice as long as wide; compound distal endopodal segment about 4.6 timeslongerthan wide (100×22 μm) and 1.7 times longer than first endopodal segment, slightly expanded distally; armedwith 7 smallsetae (all attenuated) plus small terminal claw, about one-third as long as segment.

Labrum ( Fig. 207G ) with trilobate, setulose posteriormargin. Mandible ( Fig. 207H ) with 4 teeth on coxal gnathobase; basis with 1 medial seta; exopod with 5 subequal setae; endopodwith 4 and 10 setaeon firstandsecondsegments, respectively; secondsegment ornamented with thick setules along outer margin. Maxillule ( Fig. 207I ) with 9 setae on arthrite, 1 on coxal endite, 2 on epipodite, 4 on basis (second proximal seta short and thin), 4 on exopod, and 5 and 2 on first and secondendopodal segments, respectively; secondsegment much smaller than first. Maxilla ( Fig. 208A ) 5-segmented; syncoxa with 3, 1, 2, and 3 setae on first to fourth endites, respectively; basis with strong claw (spinulose along distal half of concave margin) plus 2 setae; endopod with 1, 1, and 4 setae on first to third segments, respectively. Maxilliped ( Fig. 208B ) incompletely 2-segmentedwith 8 setae (4 proximal and 4 distal) on first segment and 2 apical setae on second.

Legs 1–4 with 3-segmented rami ( Fig. 208 C-F). Inner coxal seta absent in legs 1–4. Inner distal spine on basis of leg 1 setiform, spinulose, 68 μm long, extending to distal border of second endopodal segment. First exopodal segment of legs 3 and 4 lacking inner seta. Inner setae on endopod of leg 4 rudimentary. Armature formula for legs 1–4 as follows:

Leg 5 ( Fig. 208G ) 2-segmented; protopod with 2 rows of spinules on distal border and armed with pinnate outer distal seta; free exopodal segment about 2.4 times longerthanwide (83×35 μm), taperingdistally, densely spinulose and armed with naked apical seta and small subdistal spine.

Male. Unknown.

Remarks. Doropygella corsensis sp. nov. and D. normani have several unusual features in common including the presence of distal spines on the caudal ramus, 2 spines on the second segment of the antennule, and an ornamentation of setules along the outer margin of the second endopodal segment of the mandible. Brady (1878) illustrated these features for D. normani . These detailed similarities suggest that the two species might be considered as conspecific, but there are some significant differences. In D. normani the maxilliped is unsegmented and distally truncate (vs. incompletely 2-segmented, with a narrow secondsegment in D. corsensis sp. nov.), and according to Brady the outer spines of legs 3 and 4 are replaced by long setae (vs. the exopods of legs 3 and 4 bear outer spines in D. corsensis sp. nov.). In addition, leg 2 of D. normani also differs from that of D. corsensis sp. nov., although Brady’s illustration for leg 2 was shown as having an inner coxal seta and large, pinnate outer setae on the exopod, which is so unusual that it requires confirmation.

Figures

FIGURE 207. Doropygella corsensis sp. nov., female. A, habitus, right; B, urosome, ventral (caudal rami missing); C, left caudal ramus, dorsal; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, maxillule. Scale bars: A, 0.5 mm; B, 0.1 mm; C–F, H, 0.05 mm; G, I, 0.02 mm.

FIGURE 208. Doropygella corsensis sp. nov., female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, exopod of leg 3; F, leg 4; G, leg 5. Scale bars: 0.05 mm.