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 Periproctia longirostris sp. nov. ( Figs. 141 , 142 ) Typematerial . Holotype (intact ♀ , MNHN-IU-2014- 21266 ) , paratype (intact ♀ , MNHN-IU-2014-21267), and dissectedparatype ( ♀ , figured) from Aplidium sp., lobster wall, Mabul Malaysia ( 04°14.53 Ń , 118°37.57 É ), depth 17 m , 22 July 2004 . Etymology . The specific name refers to the elongate rostrum of the new species. Descriptionoffemale . Body ( Fig. 141A, B ) rather narrow. Body length 1.31 mm in dissected largest specimen. Prosome cylindrical, 1.04 μmlong, 0.39 mm wide, ornamented with scattered setules dorsally and laterally in posterior half. Cephalosome clearly defined; 4 pedigerous somites fused and recognizable only by weak dorsal suture lines. Brood pouch extending through all pedigerous somites ( Fig. 141A, B ). Free urosome ( Fig. 141C ) 5-segmented: genital somite and first to third abdominal somites 63×157, 61×121, 65×111, and 72×100 μm, respectively. First to third abdominal somites ornamented with rows of minute spinules ventrally. Anal somite ( Fig. 141D ) short, with pair of highly sclerotized and strongly projecting ventral protuberances ornamented with spinules. Caudal rami divergent ( Fig. 141D ), ramus slightly narrowing distally, as long as wide (29×29 μm), armed with 3 unequal claws and 3 setae (2 pinnate and 1 naked); lengths of claws 44, 22, and 18 μm. FIGURE 141. Periproctia longirostris sp. nov. , female. A, habitus, dorsal; B, habitus, left; C, urosome, ventral; D, anal somite and caudal ramus, right; E, rostrum; F, antennule; G, antenna; H, labrum; I, mandible. Scale bars: A, B, 0.2 mm; C, 0.1 mm; D-H, 0.02 mm. FIGURE 142. Periproctia longirostris sp. nov. , female. A, maxillule; B, maxilla; C, maxilliped; D, leg 1; E, leg 2; F, leg 3; G, leg 4. Scale bars: 0.02 mm. Rostrum ( Fig. 141E ) elongate, 77×44 μm, highly sclerotized, tapering towards distal beak-like process; pair of small sensillae present proximally. Antennule ( Fig. 141F ) graduallynarrowing distally, 123 μm long, and 8-segmented; armatureformula 5, 9, 8+aesthetasc, 3, 2+aesthetasc, 1, 2+aesthetasc, and 7+aesthetasc; setae crowded, proximal 2 setae markedly enlarged; most setae naked but several larger ones pinnate. Antenna ( Fig. 141G ) 4-segmented; basis and first endopodal segment each 1.3 times longer than wide and armed as usual for genus; compound distal endopodal segment 3.2 times longer than wide (64×20 μm), ornamented with scattered spinules; armed with 8 setae (including 1 pinnate and 4 bluntly tipped distal setae) plus slender terminal claw, about half as long as segment. Labrum ( Fig. 141H ) simple, smooth, with slightly convex posterior margin. Mandible ( Fig. 141I ) with 5 teeth, 1 needle-like spinule between distal second and third teeth, and 1 proximal seta on coxal gnathobase; basiswith 1 medial seta; exopod 2-segmented, with 3 and 2 setae on first and second segments, respectively, outer seta on second segment about half as long as adjacent seta; endopod with 2 and 6 setae on first and second segments, respectively. Maxillule ( Fig. 142A ) with 8 setae on arthrite, 1 on coxal endite, 2 on epipodite, 3 on medial margin of basis, 3 on exopod and 4 on endopod. Maxilla ( Fig. 142B ) 5-segmented; syncoxawith 3, 1, 2, and 3 setae on first to fourth endites, respectively; basis with 2 setae, distal seta short and naked; endopod with 1, 1, and 2 setae on first to third segments, respectively. Maxilliped ( Fig. 142C ) lobate, armed with 8 medial and 2 apical setae. Legs 1–4 ( Fig. 142 D-G) each with 3-segmented exopod and 2-segmented endopod. Inner coxal seta absent in legs 1–4. Outer seta on basis large, more than twice as long as exopod in leg 1, but small in legs 2–4. Innerdistalspineonbasisofleg 1 smooth, aslongas first endopodal segment. Third exopodal segment of legs 2–4 terminating in acutely pointed process. Leg 3 lacking inner seta on second exopodal segment. Leg 4 lacking inner seta on proximal 2 exopodal and first endopodal segments. Armature formula for legs 1–4 as follows:
Coxa Basis Exopod Endopod
Leg 1 0-0 1-I I-1; I-1; II, I, 4 0-0; 1, 2, 3
Leg 2 0-0 1-0 1-1; 1-1; 3, 1, 5 0-1; 1, 2, 5
Leg 3 0-0 1-0 1-1; 1-0; 2, 1, 5 0-1; 1, 2, 5
Leg 4 0-0 1-0 1-0; 1-0; 2, 1, 5 0-0; 1, 2, 3
Leg 5 ( Fig. 141C ) represented by small lobe on posteroventral margin of somite, armed with 2 pinnate setae distally. Male . Unknown. Remarks . Periproctia longirostris sp. nov . is characterised by multiple setal losses on legs 3 and 4. The setae lost are as follows: the inner setae on (1) the second exopodal segment of leg 3; (2) the first and (3) second exopodal segments of leg 4; (4) the first endopodal segment of leg 4; and (5) the inner seta derived from the ancestral second endopodal segment of leg 4 (now incorporated into a compound distal segment). Some reduction in leg setation was also recorded in the three speciesof Periproctia namedby Stock (1967) , P . biuncata , P . falsiarcuata , and P . triuncata . The setal losses (3), (4), and (5), as listed above, are shared with all three species, but setal loss (1) is shared only with P . falsiarcuata and P . triuncata , and setalloss (2) isshared onlywith P . biuncata . These different setation patterns on the second exopodal segment of leg 3 and on the first exopodal segment of leg 4 serve to differentiate P. longirostris sp. nov . from these three congeners. There are additional significant differences including: P. longirostris sp. nov . has 3 spines and 3 setae on the caudal ramus (vs. 2 spines and 4 setae in P . biuncata ), 6 setae on the second endopodal segment of the mandible (vs. 5 setae in all the three species described by Stock, 1967 ), 10 setaeon the maxilliped (less than 10 setae in P . biuncata and P . triuncata ), and an inner seta on the second exopodal segment of leg 1 (this seta absent in P . biuncata and P . falsiarcuata ).