Doropygus globosus Jones, 1974

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 : 313-319

Doropygus globosus Jones, 1974

( Figs. 209 , 210 )

Material examined. 1 ♀ (MNHN-IU-2018-1848) and 1 dissected ♀ (figured) from Corella eumyota Traustedt, 1882 , Portobello, New Zealand; 1 ♀ (MNHN-IU-2018- 1921) from C. eumyota , New Zealand; 1 ♀ (MNHN-IU-2009-5193) and 1 dissected ♀ from Corella brewinae Monniot F., 2013 , Stewart Island, New Zealand, collected by H. Filhol, 1875; 1 copepodid ♀ (dissected) from C. eumyota, Portobello , New Zealand, 14 September 2012.

Descriptionoffemale. Body ( Fig. 209A ) slightly compressed and moderately stout; body length 2.72 mm. Cephalosome rather small, clearly defined from metasome. Metasome gradually broadening posteriorly; pedigerous somites defined only by dorsal constrictions. Fourth pedigerous somite forming brood pouch, subovate inlateral view; incorporating fifth pedigerous somite. Free urosome ( Fig. 209B ) graduallynarrowingposteriorly, 5-segmented; genitalsomite 200×383 μm; 4 abdominal somites 250×320, 210×255, 122×214, and 128×224 μm, respectively. Distal part of anal somite and caudal rami divergent. Caudalramus ( Fig. 209C ) about 3.2 times longerthan wide (133×42 μm) and slightly longer than anal somite: armed with 6 small setae; caudal setae at most half as long as width of ramus at base; 2 proximal setae positioned at 37 and 67% of ramus length.

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

Rostrum ( Fig. 209D ) longerthanwide, tapering towards slightly angular or rounded apex. Antennule ( Fig. 209E ) broad, 9-segmented; articulation between terminal 2 segments obscure; armatureformula 3, 16, 7, 4+aesthetasc, 4, 3+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; setae extremely crowded; 2 larger setae on first segment ornamented with large, stiff setules; most setae on second to fifth segments ornamented with short spinules along margins; sixth segment with row of spinules along distal border. Antenna ( Fig. 209F ) stout, 4- segmented; coxa short and unarmed; basis slightly longer than wide, with slender knob-like process (representing exopod) at outer distal corner, bearing 2 vestigial setae; first endopodal segment expanded, as long as wide, with 1 small seta on inner margin and row of spinules in middle; compound distal endopodal segment 2.3 times longer than wide (74×32 μm) and 1.3 timeslongerthan first, ornamented with 3 rows of spinules; armed with 7 small setae plus terminal claw, 60 μm long, slightly shorter than segment.

Labrum ( Fig. 209G ) simplewithconvexdistalmargin bearing scattered minute setules. Mandible ( Fig. 209H ) with 5 teeth and 1 subsidiary, spinule-like denticle on distal side of distalmost tooth; basis with 1 seta on medial margin and 2 rows of fine setules on ventral surface; exopod armed with 5 setae and ornamented with several patches of minute spinules on ventral surface, distalmost seta half as long as other 4 setae; endopod 2-segmented with 4 setae and several rows of minute spinules on broad first segment and 10 setae and 1 distal row of minute spinules on second. Paragnath ( Fig. 209I ) lobate, bearing setules on medial surface and spinules on distal margin. Maxillule ( Fig. 209J ) with 9 setae on arthrite, 1 on coxal endite, 2 on epipodite, 3 on basis, 4 onexopodand 3 on endopod. Maxilla ( Fig. 210A ) 5-segmented; syncoxawith 3, 1, 2, and 3 setae on first to fourth endites, respectively; basis with strong claw bearing setules on concave margin plus 2 setae; endopod with 1, 1, and 4 setaeonfirst to third segments, respectively. Maxilliped ( Fig. 210B ) incompletely 2-segmented (suture line limited to medial third); first segment with 9 setae and second with 2 setae.

Leg 1 ( Fig. 210C ) with 3-segmented rami; outer setaon basis broadened proximally; innerdistal spine on basis spinulose, longerthan first endopodal segment; first exopodal segment ornamented with spinules on outer margin and outer distal surface; second and third exopodal segments each with tuft of setules on ventral (anterior) surface. Legs 2–4 with 3-segmented exopods and 2-segmented endopods ( Fig. 210D, E ); rami armed with setae rather than spines; outer and distal setae mostly spinulose. Armature formula for legs 1–4 as follows:

Leg 5 ( Fig. 210F ) 2-segmented: protopod broad with thin seta atouter distal cornerand spinulesalonginner distal border: free exopodal segment about 3.5 times longer than wide (100×29 μm), nearly rectangular, armedwith slender spine and thin seta distally; ornamented with 4 rows of spinules on dorsomedial surface and 2 rows of spinules on outer surface.

Male. Unknown.

Remarks.Thematerialexaminedincludesspecimens extracted from the type host ( Corella eumyota ) collected from close to the type locality (Wellington Harbour) in New Zealand. The general similarity between our specimens and those described by Jones (1974) strongly suggests that they belong to D. globosus . However, there are differences between our specimens and the figures of Jones (1974) in terms of body form, in the shape of the caudal ramus and leg 5, and in the setation of the maxilla. After consideration of the close similarities in the shape of the antenna, the presence of spinulose outer setae on the exopods of legs 2–4, and the characteristic, proximally swollen outer seta on the basis of leg 1, we conclude that, on balance, the evidence indicates that our material is conspecific with D. globosus and that the apparent differences are largely explained by the poor state of the material examined by Jones (1974).

Figures

FIGURE 209. Doropygus globosus Jones, 1974, female. A, habitus, right; B, urosome, ventral; C, left caudal ramus, ventral; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, paragnath; J, maxillule. Scale bars: A, 0.5 mm; B, 0.2 mm; C–F, H–J, 0.05 mm; G, 0.02 mm.

FIGURE 210. Doropygus globosus Jones, 1974, female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5. Scale bars: 0.05 mm.