Doropygus monniotorum, 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 : 361-364

Doropygus monniotorum sp. nov.

( Fig. 239 , 240 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21320 ) , paratypes (3 intact ♀♀, MNHN-IU-2014-21321), and dissectedparatypes (2 ♀♀, figured) from Hartmeyeria bouilloni Monniot C. & Monniot F., 1976 (Syntype MNHN-IT-2008-4551 = MNHNS 2/ HAR /2), MRAC-ULB (Musée Royal de l’Afrique Centrale et Université Libre de Bruxelles) Stn 338, Inhaca I., Mozambique (26°03’S, 32°54’E), 07 August 1969.

Additionalmaterial. 3 ♀♀ (MNHN-IU-2018-1867) from Polycarpa arenosa Monniot C. & Monniot F., 1976 , Inhaca Is., Mozambique, 07 August 1969.

Etymology. The new species is named after Drs. Claude and Françoise Monniot, who collected the type specimens of this species.

Descriptionoffemale. Body ( Fig. 239A ) narrow, laterally compressed. Bodylength of ovigerous female 3.27 mm in dissected specimen: prosome 2.32 mm long. Dorsal cephalic shield distinctly defined. Articulations between pedigerous somites indistinct. Brood pouch (fourth pedigeroussomite) about 1.7 timeslongerthan wide, strongly tapering posteriorly in lateral view. Free urosome ( Fig. 239B ) slender, cylindrical, 5-segmented: genitalsomite190×282μm;4 abdominalsomites223×257, 223×236, 140×205, and 159×260 μm, respectively. Anal somite with broad and deep posteromedial incision. Caudal rami divergent, elongate; each ramus ( Fig. 239C ) somewhat variable in length, about 6.0 times longer than wide (418×70 μm) in figured specimen (only 5.0 times longer than wide in another dissected specimen) and 2.6 timeslongerthan anal somite; armedwith 6 rudimentary setae; 2 proximal setae located at 23 and 57% of ramus length.

Rostrum ( Fig. 239D ) longerthan wide, weakly tapering towards rounded apex. Antennule ( Fig. 239E ) about370μmlong,9-segmented;firstandsecondsegments distinctly broader than distal segments; articulations between three distal segments incomplete; armature formula 3, 17, 6, 5, 3, 2+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; 2 setae on first segment pinnate and larger than other setae, all othersetae naked.Antenna ( Fig. 239F ) moderately slender, 4-segmented; coxa unarmed; basis 147×69 μm, with 2 small setae; first endopodal segment 90×58 μm, not expanded, with 1 small seta; compound distal endopodal segment about 3.3 times longer than wide (127×38 μm); armed with 7 setae plus terminal claw 74 μm long, 0.58 times as long as segment.

Labrum ( Fig. 239G ) asin D. pulex . Mandible ( Fig. 239H ) different from D. pulex in having distalmost seta on exopodal segment distinctly shorter, about 0.7 times as long as other 3 proximal setae, and in second endopodal segment bearing 9 setae. Paragnath ( Fig. 239I ) with semicircular lobule at outer distal corner and setulose medial margin. Maxillule ( Fig. 239J ), maxilla ( Fig. 240A ), and maxilliped ( Fig. 240B ) as in D. pulex .

Leg 1 ( Fig. 240C ) with 3-segmented rami, armed as in D. pulex . Legs 2–4 with 3-segmented exopods and 2- segmented endopods ( Fig. 240D, E ); endopod longerthan exopod in legs 2 and 3, but similar in length to exopod in leg 4. Inner coxal seta and inner setae on endopod of leg 4 well-developed, all pinnate. Armature formula for legs 1–4 asin D. pulex .

Leg 5 ( Fig. 240F ) slender: protopod notarticulated at base, with 1 small outer seta subdistally and row of minute spinules at inner distal corner; free exopodal segment 3.9 times longerthan wide (164×42 μm); armed distally with 2 setae of different thickness and length and ornamented with 3 oblique rows of minute spinules on dorsomedial surface.

Male. Unknown.

Remarks. Doropygus monniotorum sp. nov. belongs to the D. pulex complex. Differences from D. pulex are: (1) the brood pouch invariably tapers more strongly; (2) the caudal ramus is more elongate (more than 5.0 times longer than wide), and is more than twice as long as the anal somite; (3) the setae on the antennule are better developed and the 2 large setaeon first segment are pinnate; (4) the terminal claw of the antenna is 0.58 times as long as the compound distal endopodal segment; (5) the distalmost (fourth) seta on the mandibular exopod is about 0.7 times as long as the other 3 setae; and (6) the exopod of leg 5 is more slender (3.9 times longer than wide).

Figures

FIGURE 239. Doropygus monniotorum sp. nov., female. A, habitus, right; B, urosome, ventral; C, left caudal ramus, dorsal; 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, 0.1 mm; G, I, J, 0.05 mm.

FIGURE 240. Doropygus monniotorum sp. nov., female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5. Scale bars: A, 0.05 mm; B–F, 0.1 mm.