Doropygella calla, 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 : 307-310

Doropygella calla sp. nov.

( Figs. 205 , 206 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21303 ) , paratypes (2 intact ♀♀, MNHN-IU-2014-21304), anddissectedparatype (♀, figured) from Culeolus hospitalis Monniot F. & Monniot C., 2003 (MNHN-IT-2008-2474 = MNHN S2/ CUL /52), Vanuatu, SE Santo, Guyot Bougainvillé, “Alis” (16°01’S, 166°40’E), depth 1014-1050 m, Bouchet & Richer de Forges-IRD coll., 10 October 1994.

Etymology. The specific name is derived from the Latin callo (= thick skinned), referring to the thick, rigid exoskeleton of the new species.

Descriptionoffemale. Body ( Fig. 205A ) distinctly segmented with rigid exoskeleton. Body length 4.35 mm; prosomeabout 3.2 mm long. Cephalosome very broad, with ventrolaterally expanded dorsal cephalic shield. First pedigerous somite free, with large ventral tubercle just anterior to intercoxal plate of leg 1 ( Fig. 206D ). Second and third pedigerous somites each with well-developed, rounded epimera. Fouth pedigerous somite forming sub-circular brood pouch, tapering in distal third (in lateral view) towards pointed posterodorsal margin. Free urosome ( Fig. 205B ) 5-segmented; genitalsomite short; 4 free abdominal somites expanded posteriorly, 459×474, 326×430, 237×356, and 422×378 μm, respectively. Caudalramus ( Fig. 205C ) about 4.1 timeslongerthan wide (441×107 μm) and slightly longer than anal somite, gradually narrowing distally, with distal part attenuated: armed with very small, thin setae; 4 distal setae hardly visible; outer proximal and dorsal setae about half as long as width of ramus at base, located at 35 and 63% of ramus length, respectively.

	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, 40-1; 0-2; 1, II, II+1
Leg 3	0-0	1-0	I-1; I-1; III, I, 4	0-1; 0-1; 1, II,
				II+1
Leg 4	0-0	1-0	I-0; I-1; II, I, 3	0-1; 0-1 (or 0-2);
				1, II, I+1

Rostrum ( Fig. 205D ) longerthanwide; proximal two-thirds with nearly parallel lateral margins, distal third acutely convex. Antennule ( Fig. 205E ) 9-segmented; first 3 segments greatly broadened, distal 6 segments slender, cylindrical; armatureformula 2, 17, 6, 2, 4, 4, 2, 3, and 7+aesthetasc; all setae thin and naked. Antenna ( Fig. 205F ) robust, comprising coxobasis and 2-segmented endopod; coxobasis unarmed, narrowing in middle, ornamented with few setules in mid inner margin; first endopodal segment wider than long, unarmed; compound distal endopodal segment much narrower than proximal segments, about 3.3 timeslongerthan wide (167×50 μm); armed with 10 small setae and row of fine spinules at outer subdistal region, plus terminal claw about half as long as segment.

Labrum ( Fig. 206A ) with trilobate, setulose free posterior margin. Mandible ( Fig. 205G ) with 5 teeth on coxalgnathobase; basiswith 1 setaonmedial margin; exopod short, unsegmented with 5 large, equal setae; endopod with 4 and 10 setae on first and second segments, respectively. Maxillule ( Fig. 205H ) with 10 setaeon arthrite, 1 on coxal endite, 2 on epipodite, and 4 on basis (proximal seta small), 4 on exopod, and 6 on endopod; endopod subdivided by incomplete lateral suture into proximal part bearing 2 medial setae and short distal part bearing 4 setae. Maxilla ( Fig. 206B ) 4-segmented; syncoxa with 4, 1, 2, and 3 setae on first to fourth endites, respectively, one seta on first endite short and naked; basis with slender claw plus 1 seta; 2-segmented endopod very small, first segment unarmed, secondsegment bearing 5 small naked setae. Maxilliped ( Fig. 206C ) 3-segmented, articulation incomplete between first and second segments; first segment with 6 setae (1 proximal and 5 distal) and ornamented with scattered minute spinules; second segment unarmed but with few setules on inner margin; small third segment with 3 large setae.

Legs 1–4 ( Fig. 206 D-G) with broad coxa and basis and 3-segmented rami: exopods and endopods wellseparated from each other. Inner coxal seta absentin all legs. Spines on exopods and endopod strong, with smooth unornamented margins. Inner setae on second and third exopodal segments of leg 4 small and naked. Second endopodal segment of leg 4 with 1 or 2 inner setae. Armature formula for legs 1–4 as follows:

Leg 5 ( Fig. 206H ) consistingof protopod and exopod; protopod withthinouter distal seta; free exopodalsegment about 3.8 times longerthan wide (215×56 μm), bearing thin seta on attenuated apex; segment unornamented, lacking any spinule rows. Leg 6 absent.

Male. Unknown.

Remarks. Among its congeners, Doropygella calla sp. nov. is most similarto the type species, D. thorelli , because both these two species share the possession of a small 2-segmented endopod on the maxilla, which has an unarmed first segment and bears 5 setae on the second, and both have spines on the third endopodal segments of legs 2–4.

The salient differences between the new species and D. thorelli are: (1) the free exopodal segment of leg 5 is short (only 1.6 timeslongerthan wide) in D. thorelli , but elongate (3.8 timeslongerthan wide) in D. calla sp. nov.; (2) the third exopodal segment of leg 2 is armed with 4 spines and 5 setae (formula III, I, 5) in D. thorelli , but with 4 spines and 4 setae (III, I, 4) in D. calla sp. nov.; (3) the third endopodal segment of legs 2 and 3 is armed with 3 spines and 3 setae (1, II, I+2) in D. thorelli , but with 4 spines and 2 setae (1, II, II+1) in D. calla sp. nov.; (4) the first exopodal segment of leg 4 bears an inner seta in D. thorelli , but this seta is absent in D. calla sp. nov.; and (5) the third exopodal segment of leg 4 is armed with 3 spines and 4 setae (II, I, 4) in D. thorelli , but with 3 spines and 3 setae (II, I, 3) in D. calla sp. nov. These differences are sufficient to justify the establishment of the new species.

Figures

FIGURE 205. Doropygella calla sp. nov., female. A, habitus, right; B, ursome, ventral; C, left caudal ramus, dorsal; D, rostrum; E, antennule; F, antenna; G, mandible; H, maxillule. Scale bars: A, 0.5 mm; B, 0.2 mm; C, 0.1 mm; D–H, 0.05 mm.

FIGURE 206. Doropygella calla sp. nov., female. A, labrum; B, maxilla; C, maxilliped; D, leg 1; E, leg 2; F, endopod of leg 3; G, leg 4; H, leg 5. Scale bars: 0.05 mm.