Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata) Author Kim, Il-Hoi 0000-0002-7332-0043 Korea Institute of Coastal Ecology, Inc., 802 - ho, 302 - dong, 397 Seokcheon-ro, Ojeong-gu, Bucheon, Gyeonggi-do 14449, Republic of Korea ® ihkim @ gwnu. ac. kr; https: // orcid. org / 0000 - 0002 - 7332 - 0043 ihkim@gwnu.ac.kr Author Boxshall, Geoff A. 0000-0002-7332-0043 Korea Institute of Coastal Ecology, Inc., 802 - ho, 302 - dong, 397 Seokcheon-ro, Ojeong-gu, Bucheon, Gyeonggi-do 14449, Republic of Korea ® ihkim @ gwnu. ac. kr; https: // orcid. org / 0000 - 0002 - 7332 - 0043 ihkim@gwnu.ac.kr text Megataxa 2020 2020-12-24 4 1 1 6 http://zoobank.org/3fdd970e-62f1-4f67-8cce-10870bdb3c01 journal article 54097 10.11646/megataxa.4.1.1 7c9bc39d-9910-46f1-9558-c0647b9cbbdb 2703-3090 4591138 Notodelphys echinata Monniot C., 1961 ( Figs. 13–15 ) Material examined . 1 copepodid V (MNHN-IU-2018- 1763) from Microcosmus polymorphus Heller, 1877 , Banyuls, France ; 1 ♀ (dissected) from M . nudistigma Monniot C., 1962 , Portugal ; 1 ♀ (MNHN-IU-2018-1764) from M . polymorphus , Portugal ; 11 ♀♀ , 4 ♂♂ (MNHN-IU-2018-1765) from M . polymorphus , Dakar , Senegal , collected by Leung Tack, 1966–1969; 2 ♀♀ (MNHN-IU-2018-1766) from M . polymorphus , Dakar , Senegal ; 1 ♀ , 1 ♂ (MNHN-IU-2018-1767) and dissected 1 ♀ , 1 ♂ (figured) from M . polymorphus , Dakar , 1966–1968. Supplementary description of female . Body ( Fig. 13A ) about 3.7 mmlong. Freeurosome ( Fig. 13B ) 5- segmented; genital and 4 freeabdominal somites 159×280, 221×238, 245×200, 245×182, and 141×164 μm. Caudal ramus about 4.6 times longer than wide (270×59 μm), setulose along inner margin; armed with 6 setae, outer lateral seta located at 55% of ramus length. FIGURE 12. Notodelphys caenulea Thorell, 1859 , female. A, habitus, right; B, anal somite and caudal ramus, dorsal; C, rostrum; D, antenna; E, mandible; F, maxillule; G, maxilla; H, right leg 5, ventral. Scale bars: A, 0.5 mm; B–H, 0.05 mm. FIGURE 13. Notodelphys echinata Monniot, 1961 , female. A, habitus, right; B, urosome, ventral; C, rostrum; D, antennule; E, antenna; F, labrum; G, mandible; H, paragnath; I, maxillule. Scale bars: A, 0.5 mm; B, 0.1 mm; C–I, 0.05 mm. FIGURE 14. Notodelphys echinata Monniot, 1961 , female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5. Scale bars: A, B, F, 0.05 mm; C, D, E, 0.1 mm. FIGURE 15. Notodelphys echinata Monniot, 1961 , male. A, habitus, right; B, antennule; C, left legs 5 and 6. Scale bars: A, 0.2 mm; B, C, 0.05 mm. Rostrum ( Fig. 13C ) tapering towards truncate apex. Antennule ( Fig. 13D ) 345 μm long and 13-segmented; segmental fusions I-II, III-XI , XII-XIV , XV-XVI , XVII-XVIII , XIX , XX , XXI , XXII , XXIII , XXIV , XXV , XXVI-XXVIII ; armatureformula 3, 17, 6, 6+aesthetasc, 6, 3, 2, 2, 1, 1, 2, 2+aesthetasc, and 7+aesthetasc; fifth segment ( XVII-XVIII ) with subdivision on ventral surface; longer setae on proximal segments pinnate (as figured). Antenna ( Fig. 13E ) with short unarmed coxa; basis with 2 subequal setae representing exopod; first endopodal segment with seta on inner margin; compound distal endopodal segment 3.1 times longer than wide, armed with terminal claw plus 10 setae (arranged as 1, 1, 3, 2, and 3). Labrum ( Fig. 13F ) with setulose posterolateral lobes and linear mid-posterior margin ornamented with spinules and setules. Mandible ( Fig. 13G ) with 5 teeth (second distal tooth acutely pointed) and 2 setae on coxal gnathobase; basiswith 1 setaonmedial margin; exopod obscurely segmented, armed with 5 setae, distalmost seta distinctly larger than others; endopod with 3 and 9 setae on first and second segments, repectively. Paragnath ( Fig. 13H ) with denticle apically and setules on medial surface. Maxillule ( Fig. 13I ) with 9 setaeon precoxal arthrite, 1 setaon on coxal endite, 2 setaeon coxal epipodite, 3 setae (proximal seta muchsmaller than distal 2) onmedial margin of basis; 4 setae distally on exopod and 5 setae on endopod. Maxilla ( Fig. 14A ) 5-segmented; syncoxawith 4, 1, 2, and 3 setae on first to fourth endites, respectively; basis withlarge claw plus 2 setae; 3-segmented endopod with 1, 1, and 3 setae, respectively. Maxilliped ( Fig. 14B ) 3-segmented and armed with 10, 1, and 3 setae on first to third segments, respectively; seta on second segment and 1 setaon third segment spiniform. Legs 1–4 with 3-segmented rami; armatureformula as in generic diagnosis. Inner seta on coxa of leg 1 ( Fig. 14C ) plumose, those of legs 2–4 naked. Inner distal spine on basis of leg 1 distinctly shorter than first endopodal segment and spinulose along both margins; distalmost spine on third exopodal segment curved. Outer spines on exopods of legs 2–4 setiform, elongate and smooth ( Fig. 14D, E ). Leg 5 ( Fig. 14F ) protopodornamented withnumerous fine spinules on ventral surface, armed with naked seta on tip of stout outer distal process; exopodal segment sub-rectangular, well-developed, about 2.3 times longer than wide (82×36 μm), spinulose on ventral surface: armed with 1 spine (27 μm long) and 1 naked seta (61 μm long). Supplementarydescriptionofmale . Body ( Fig. 15A ) curved ventrally, 1.90 mmlong. Urosome 6- segmented. Caudal ramus about 4.1 timeslongerthan wide (160×39 μm). Rostrum as in female. Antennule ( Fig. 15B ) 10- segmented; geniculate between eighth ( XIX-XX ) and ninth ( XXI-XXIII ) segments; armatureformula 3, 17, 2, 2, 2, 5+aesthetasc, 4, 2, 1, and 10+aesthetasc. Antenna, mouthparts, and legs 1–4 as in female. Leg 5 ( Fig. 15C ) similartothatof female; protopod with less pronounced outer distal process; exopodal segment about twice as long as wide (47×24 μm). Leg 6 represented by 2 naked setae and 1 small spinulose, spiniform setaon genital operculum ( Fig. 15C ). Remarks . The type material of this species was obtained from the ascidian Microcosmus polymorphus collected off the French Mediterranean coast ( Monniot, 1961 ). Our specimens from Dakar display the key characteristic features of N. echinata , including the 13- segmented antennule, the naked setiform outer spines on the exopods of legs 2–4, and the well-developed leg 5 exopod which is spinulose and more than twice as long as wide. However, there are some minor differences: in his original description Monniot (1961) described the caudal ramus as 6 times longerthan wide and 1.5 times longer than the anal somite, the second endopodal segment of the mandible was armed with 10 setae, and the maxilla had 3 setae (2 large and 1 small) on the first endite of the syncoxa. In contrast, in the specimens from Dakar the caudalramus is only 4.6 timeslongerthan wide and 1.9 timeslongerthan the anal somite, the second endopodal segment of the mandible is armed with 9 setae, and the maxilla has 4 setae (3 large and 1 small) on the first endite of the syncoxa. We consider that these discrepancies can probably best be interpreted as geographical variation and that our specimens can be identified with confidence as N . echinata .