Nobinerilla ovata, 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 : 290-293

Nobinerilla ovata gen. et sp. nov.

( Figs. 194 , 195 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21298 ) , paratypes (4 intact ♀♀, MNHN-IU-2014-21299), and dissected paratypes (2 ♀♀, figured) from Eudistoma hospitale Monniot F., 1998 , Papua New Guinea (09°05 Ś, 149°19 É), 22 January 2002.

Etymology. The specific name refers to the ovoid prosome of this species.

Descriptionoffemale.Body( Fig.194A )compressed, oval in lateral view, 1.80 mm long. Cephalosome, with rounded posterolateral corners, distinctly defined from metasome. Metasome unsegmented, bearing 2 pairs of small epimeral wings; wings taperingdistally towards rounded apex. Freeurosome ( Fig. 194B ) 5-segmented: genital somite short and wide; first abdominal somite longest. Caudal ramus ( Fig. 194C ) about 2.5 times longer than wide (81×32 μm): armedwith 6 thick, naked setae; outer lateral and dorsal setae positioned at 56% and 75% of ramus length, respectively; longest seta 85 μm long, slightly longer than ramus; all other setae shorter than ramus.

	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	1-1; 1-1; 3, 1, 5	0-1; 0-2; 1, 2, 3
Leg 3	0-1	1-0	1-1; 1-1; 2, 1, 5	0-1; 0-2; 1, 2, 3
Left leg 4	0-0	1-0	1-1; 1-1; 2, 1, 5	0-0; 0-0; 1, 2, 2
Right leg 4 0-0		1-0	1-0; 1-1; 2, 1, 5	0-0; 0-0; 1, 2, 2

Rostrum short, more than twice as wide as long, withrounded apex. Antennule ( Fig. 194D ) 224 μm long, 8-segmented; fifth segment with partial subdivision on anterior surface; armatureformula 3, 16, 6, 3+aesthetasc, 4, 3, 4+aesthetasc, 7+aesthetasc; setae generally short, all naked. Antenna ( Fig. 194E ) 4-segmented; coxa unarmed; basis also unarmed, about 1.3 times longerthan wide; first endopodal segment slightly shorter than basis, armed with 1 inner seta; compound distal endopodal segment twice as long as wide (46×23 μm) and 1.2 times longer than first; armed with 7 setae plus large terminal claw, as long as segment.

Labrum ( Fig. 194F ) with minutesetules on posterior marginand short, spinulose posteromedian lobe.Mandible ( Fig. 194G ) with 5 teeth on coxal gnathobase; basiswith 1 medial seta; exopod with 5 setae, outer distal seta shorter than other 4 setae; endopod incompletely articulated from basis, with 4 and 7 setae on first and second segments, respectively.Paragnathdenselysetuloseonmedial margin; with short, blunt apical process. Maxillule ( Fig. 194H ) with 9 setae on arthrite, 1 broad seta on coxal endite, 2 on epipodite, 3 on basis, and 4 each on exopod and endopod; exopod distinctly larger than endopod. Maxilla ( Fig. 194I ) with 9 setaeon syncoxa, clawplus 2 setaeon basis, and 1, 1, and 2 setae on first to third endopodal segments, respectively; claw on basis elongate, with spinules on both margins. Maxilliped ( Fig. 195A ) unsegmented, truncate apically, armed with 10 medial setae and 1 outer distal seta.

Legs 1–4 ( Fig. 195 B-G) with 3-segmented rami. Inner coxal seta present in leg 3, absent in legs 1, 2, and 4. Outer seta on basis large in leg 1, small in legs 2–4. Inner distal spine on basis of leg 1 slightly longer than first endopodal segment, smooth, 40 μm long. Left and right legs in legs 2–4 exhibiting same armature formula, but left exopods longer than right and armed with attenuated setae. Setae on right exopods of leg 2-4 blunt at tip and shorter than those of left exopods. In left legs 2–4 exopod about 2.1 times longer than endopod in leg 2, about 1.8 times longer in legs 3 and 4. These ratios smaller in right legs 2–4. Armature formula for legs 1–4 as follows:

Leg 5 consisting of short protopodal plate and free exopod; protopodal plate with outer distal seta and row of fine spinules near base of exopod on each side; exopod ( Fig. 195H ) elongate, narrowing at proximal third, about 4.8 times longerthanwide (101×21 μm); armedwith 1 seta at outer distal corner and 1 setal vestige at inner distal corner; ornamented with 4 rows of minute spinules on inner side.

Remarks. Nobinerilla ovata gen. et sp. nov. has metasomal wings derived from the epimera of the second and third pedigerous somites, as in N. alata gen. et sp. nov. and other species described below. However, unlike any other similar species, it possesses 7 setae on the second endopodal segment of the mandible. Although this character state is shared with N. mammillata gen. et sp. nov. ( Table 4), metasomal wings are not found in N. mammillata gen. et sp. nov., and the inner setaon the secondendopodal segment of leg 4 is not observable in N. ovata gen. et sp. nov. (cf. present in N. mammillata gen. etsp. nov.).

Figures

FIGURE 194. Nobinerilla ovata gen. et sp. nov., female. A, habitus, right; B, urosome, ventral; C, caudal ramus, dorsal; D, antennule; E, antenna; F, labrum; G, mandible; H, maxillule; I, maxilla. Scale bars: A, 0.2 mm; B–D, F, G, 0.05 mm; E, H, I, 0.02 mm.

FIGURE 195. Nobinerilla ovata gen. et sp. nov., female. A, maxilliped; B, leg 1; C, left leg 2; D, right leg 2; E, left leg 3; F, left leg 4; G, right leg 4; H, exopod of leg 5. Scale bars: A, H, 0.02 mm; B–G, 0.05 mm.