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 Pronotodelphys caledonica gen. et sp. nov. ( Figs. 4–6 ) Type material . Holotype (intact ♀ , MNHN-IU-2014-21214 ) from Ascidia munda Sluiter, 1898 , New Caledonia, MUSORSTOM 4 CC 147, New Caledonia , Grand Passage , N/O “Vauban” ( 19°33.8’S , 163°38.5’E ), depth 46 m , Bouchet & Richer de Forges-IRD coll., 13 September 1985 ; paratype ( ♀ , dissected and figured, MNHN-IU-2014-21215) from A. munda , Baie des Citrons , New Caledonia , September 1985 . Additionalmaterial . 1 ♀ , 1 ♂ (both dissected; male figured) from Ascidia tapuni Monniot C. and Monniot F., 1987 , Îlot Maître, New Caledonia , Stn NC 16, depth 3–8 m , Monniot coll., 12 September 1985 . Etymology . The name of the new species is from the name of the type locality, New Caledonia . Description of female . Female body ( Fig. 4A ) comprising cephalosome, free first to third pedigerous somites, and dorsal brood pouch incorporating fourth and fifth pedigerous somites. First pedigerous somite lacking distinct tergite and largely concealed; second and third pedigerous somites each with well-developed tergite; third pedigerous somite with concave posterior margin. Fourth pedigerous somite forming oval brood pouch incorporating fused fifth pedigerous somite. Free urosome ( Fig. 4B ) slender, consistingof genital and 4 abdominal somites, with only anal somite clearly visible in dorsal view. Suture between genital and first abdominal somites distinct dorsally but obscure ventrally. Genital somiteshort, 145×415 μm; 4 abdominalsomites 320×298, 305×265, 255×240, and 196×240 μm, respectively. Anal somite ornamented with setules posteriorly on lateral surfaces. Caudal rami slender (473×72 μm) and slightly divergent; each ramus ( Fig. 4C ) about 6.6 times longer than wide; densely ornamented with thin, hair-like setules on all surfaces: armed with 6 setae, setae naked or weakly pinnate; outer lateral seta located about at mid-length of ramus. Rostrum ( Fig. 4D ) 161×130 μm, taperingdistally towards weakly bilobed tip. Antennule ( Fig. 4E ) 13- segmented with segmental fusion pattern as in generic diagnosis; armatureformula 3, 18, 6, 4+aesthetasc, 4, 2, 2, 1+aesthetasc, 1, 1, 2, 2+aesthetasc, and 7+aesthetasc; setaeon proximal segments mostly pinnate, setaeon distal segments mostly naked (as figured). Antenna ( Fig. 4F ) consisting of coxa, basis and 2-segmented endopod: coxa short, unarmed; basis with 1 inner distal seta plus 2 unequal outer distal setae representing exopod; larger exopodal seta as long as second endopodal segment and pinnate, smaller seta naked and about 0.25 times as long as larger: first endopodal segment with 1 setaon inner margin; compound distal endopodal segment slender, more than 5 times as long as wide, with terminal claw plus 11 setae (3 of distal setae with blunt tips). Labrum ( Fig. 4G ) steeply tapering posteriorly and ornamented with minute spinules on distal part of lateral margins and on posterior margin of semicircular posteromedianlobe,andwithsetulesbothsidesof posterior margin. Mandible ( Fig. 4H ) with coxalgnathobase cutting margin conspicuously broad and bearing 6 teeth and 2 small setae; proximal 4 teeth blunt; second distal tooth acutely pointed, ornamented with minute spinules along proximal margin: palp consistingof basis, exopod, and 2-segmented endopod; basis with 1 plumose and proximally expanded seta on medial margin; exopod with 5 setae, distalmost seta distinctly larger than other 4, first exopodal segment ornamented with minute spinules proximally on inner surface: endopod with 4 and 10 setae on first and second segments, respectively. Paragnath ( Fig. 4J ) as small lobe produced into semicircular lobule at outer distal corner, with patch of spinules apically plus dense cover of setules on medial surface. Maxillule ( Fig. 4I ) with 10 setae on arthrite, 1 on coxal endite, 2 on epipodite, and 3 (2 shorter proximal and 1 long distal) onmedial margin of basis; exopod with 4 setae distally; endopod 2-segmented with 3 setae on medial margin of first segment and 4 setae on second segment. Maxilla ( Fig. 5A ) 5-segmented; syncoxawith 3 + 1 smallseta, 1, 2, and 3 setae on first to fourth endites, respectively; basis with smooth claw plus 2 setae; endopod with 1, 1, and 4 setae on first to third segments, respectively. Maxilliped ( Fig. 5B ) 4-segmented, armedwith 9, 0, 2, and 3 setae on first to fourth segments, respectively; setae on third segment pectinate along proximal margin; small fourth segment bearing 1 naked and 2 pinnate setae. Legs 1–4 biramous with 3-segmented rami. Outer seta on basis pinnate in leg 1, but naked in legs 2–4. Innerdistalspineonbasisofleg 1 ( Fig. 5C ) 79 μmlong, shorter than first endopodal segment; second outer spine of third exopodal segment distinctly shorter than first and third spines. Outer margin of first endopodal segment ornamented with spinules in leg 2 ( Fig. 5D ) but with setules in legs 1, 3 and 4. First endopodal segment of legs 3 ( Fig. 5E ) and 4 elongate. Outer setae on exopods of legs 2–4 stiff, spiniform. Armature formula for legs 1–4 as in generic diagnosis. Leg 5 ( Fig. 5F ) consistingof protopod and exopod both ornamented with numerous setules on surfaces (dots on Fig. 5F indicate insertions of setules). Left and right protopods fused medially to form broad plate bearing naked outer basal seta on each posterolateral corner and ornamented with irregular spinule row along mid-posterior margin; paired exopods free, exopodal segment elliptical, armed distally with 1 spiniform seta and 1 smaller, thin seta; ornamented with about 10 spinules along inner margin. FIGURE 4. Pronotodelphys caledonica gen. et sp. nov. , female. A, habitus, dorsal; B, urosome, dorsal; C, left caudal ramus, dorsal; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, maxillule; J, paragnath. Scale bars: A, 0.5 mm; B, 0.2 mm; C–F, H, 0.1 mm; G, I, J, 0.05 mm. FIGURE 5. Pronotodelphys caledonica gen. et sp. nov. , female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 3; F, left and right leg 5. Scale bars: 0.1 mm. FIGURE 6. Pronotodelphys caledonica gen. et sp. nov. , male. A, habitus, dorsal; B, urosome, ventral; C, left caudal ramus, ventral; D, antennule; E, legs 5 and 6. Scale bars: A, 0.2 mm; B, 0.1 mm; C–E, 0.05 mm. Descriptionofmale . Body ( Fig. 6A ) cyclopiform, narrowingposteriorly.Cephalosomedistinctlybroaderthan freepedigerous somites. Urosome ( Fig. 6B ) 6-segmented: fifth pedigerous somite free, clearly defined anteriorly and posteriorly, 89×163 μm; genital somite 116×145 μm, with parallel lateral margins; 4 free abdominal somites gradually shorter, 107×115, 102×104, 85×96, and 67×91 μm, respectively. Anal somite ornamented with row of spinules on posteroventral margin and paired papilliform tubercles on inner posteroventral margin ( Fig. 6B, C ). Caudalramus ( Fig. 6C ) about 4.5 timeslongerthan wide (108×24 μm), ornamented with sparse setules on all surfaces and with scattered spinules along posteroventral margin; outer lateral seta located at 60% of ramus length. Rostrum asin female. Antennule ( Fig. 6D ) 12- segmented, segmental fusion pattern as in generic diagnosis; geniculate between tenth (XIX-XX) and eleventh (XXI-XXIII) segments; seventh segment with partial suture on ventral surface; armature formula 3, 5, 12, 2, 2, 2, 4+aesthetasc, 2, 2, 4, 2, and 9+aesthetasc; terminal segment blunt at tip. Antenna as in female. Mouthparts and legs 1–4 also as in female. Leg 5 ( Fig. 6E ) protopod fused with somite, lacking ornamentation of spinules; free exopodal segment about twice as long as wide (35×17 μm) with straight inner margin; spiniform distal seta shorter than outer seta. Leg 6 ( Fig. 6E ) represented by 2 setae and 1 spiniform process on genital operculum.

Coxa	Basis	Exopod	Endopod
Leg 1	0-1	1-I	I-1; I-1; III, I,	40-1; 0-1; 1, 2, 3
Legs 2 &	30-1	1-0	I-1; I-1; III, I,	50-1; 0-2; 1, 2, 3
Leg 4	0-1	1-0	I-1; I-1; II, I, 5	0-1; 0-2; 1, 2, 2

Remarks. The type species differs from P. villosa in the setation pattern of the 4-segmented maxilliped: in the type species P. caledonica gen. et sp. nov. the pattern is 9, 0, 2, and 3, whereas in P. villosa it is 9, 0, 3, and 2. This difference serves to separate the two congeners. In addition, the proportions of the caudal ramus are significantly different between the two species: the caudal rami are about 4.5 times ( Ooishi, 1962 ) to 4.6 times ( Kim, 2012 ) longer than wide in P . villosa , but about 6.6 times longerthan wide in P . caledonica gen. et sp. nov. These differences are sufficient to justify the establishment of the new species.