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 Notoixys hirsuta gen. et sp. nov. ( Figs. 342 , 343 ) Typematerial . Holotype (intact ♀ , MNHN-IU-2014- 21389 ) , paratypes (6 intact ♀♀ , MNHN-IU-2014-21390), and dissected paratypes ( 2 ♀♀ , figured) from Aplidium imbutum Monniot C. & Monniot F., 1983 , South Orkney Islands , Cruise876,Antarctic,“Islas Orcadas ”,( 60°27.8’S , 46°23.1’W ), depth 93-102 m , trawl, 16 February 1976 .
Coxa Basis Exopod Endopod
Leg 1 0-1 1-I 1-1; 1-1; 3, 1, 4 0-1; 1, 2, 4
Leg 2 0-0 1-0 1-1; 4, 1, 6 0-1; 1, 2, 5
Leg 3 0-0 1-0 1-1; 4, 1, 6 1, 2, 6
Leg 4 0-0 1-0 1-1; 1-1; 2, 1, 5 0-1; 1, 2, 4
Etymology . The specific name refers to the hirsute body of the new species. Descriptionoffemale . Body ( Fig. 342A ) swollen, 1.20 mmlong. Prosome 0.91 mmlong; dorsalcephalic shield expanded ventrolaterally, surface densely setulose along ventral border, with paired acutely-pointed posterolateralhorn-likeprocesses ( Fig. 342B ). Metasome almost spherical, without trace of articulation, slightly longerthanwide. Freeurosome ( Fig. 342C ) 5-segmented: genital somite much wider than long: 4 abdominal somites setulose on ventral surface, 124×160, 67×127, 44×104, and 58×96 μm, respectively. Caudalramus ( Fig. 342D ) small, setulose, slightly tapering distally, about 2.0 times longer than wide (43×21 μm); caudal setae not discernible from setules. Rostrum ( Fig. 342E ) about 1.2 timeslongerthan wide, densely covered with setules, tapering to blunt apex. Antennule ( Fig. 342F ) narrow, 147 μmlong, indistinctly 7-segmented; second to fourth segments each bearing 1 or 2 incomplete subdivisions on posterior surface; armature formula 2, 14, 8, 3+aesthetasc, 1, 4, and 5+aesthetasc. Antenna ( Fig. 342G ) 4-segmented; proximal 3 segments unarmed; terminal segment about 3.4 times longer than wide (57×17 μm) and distinctly longerthan first: armed with 9 setae (arranged as 1, 3, 2, and 3) plus small terminal claw, about 0.3 times as long as segment. Labrum ( Fig. 342H ) withlarge posteromedian protuberance bearing setules along posterior margin. Mandible ( Fig. 342J ) with narrow coxalgnathobase bearing 6 unequalteeth on medial margin: basis with 1 seta onmedial margin: exopodwith 5 setae; outerdistalseta short, about half as long as adjacent seta: endopod with 1 and 6 setae on first and second segments, respectively. Maxillule ( Fig. 342I ) armedwith 6 setaeon arthrite, 1 on epipodite, 2 on basis, 4 onexopodand 3 on endopod; setae on endopod longer than those on exopod; arthrite ornamented with patch of setules on proximal medial margin. Maxilla ( Fig. 343A ) 5-segmented; syncoxa armed with 3, 1, 1, and 1 setae on first to fourth endites, respectively; basiswith 3 setae; first to third endopodal segments with 1, 1, and 3 setae respectively. Maxilliped ( Fig. 343B ) unsegmented, narrowing distally, armed with 3 setae distally. Legs 1–4 ( Fig. 343 C-F) biramous; all setae on legs short and naked except pinnate inner coxal seta and outer seta on basis of leg 1. Leg 1 endopod distinctly 2- segmented; but segmentation of other rami of legs 1–4 obscure. Inner coxal seta present only in leg 1. Inner distal seta on basis of leg 1 smooth, 19 μm long. Armature formula for legs 1–4 as follows: Leg 5 ( Fig. 342B ) represented by 2 small setae on posteroventral margin of somite, near base of free urosome. Male . Unknown. Remarks . Notoixys hirsuta gen. et sp. nov. possesses a seta-tipped coxal endite on the maxillule and has 3 setae on the third endopodal segment of the maxilla. Within the genus, both features are shared only with the type species, N . heardensis gen. et sp. nov. However, they can be distinguished by the number of setae on the second endopodal segment of the mandible ( 6 in D . hirsuta gen. etsp. nov. comparedto 5 in N . heardensis gen. et sp. nov. ). The rami of legs 2–4 are also different: the exopods of legs 3 and 4 are armed with totals of 13 and 12 setae, respectively in N . hirsuta gen. et sp. nov. , and the endopods are armed with 9 and 8 setae, respectively. In contrast, in all three congeners the numbers of these setae are lower, for example, with a maximum of 12 and 11, respectively, on the exopods of legs 3 and 4, and 6 setae on each endopod, as found in N . heardensis gen. et sp. nov. FIGURE 342. Notoixys hirsuta n gen. et sp. nov . , female. A. habitus, right; B, cephalic horn; C, leg 5 and urosome, ventral; D, right caudal ramus, dorsal; E, rostrum; F, antennule; G, antenna; H, labrum; I, maxillule; J, mandible. Scale bars: A, C, 0.1 mm; B, D, F–J, 0.02 mm; E, 0.05 mm. FIGURE 343. Notoixys hirsuta gen. et sp. nov . , female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 3; F, leg 4. Scale bars: 0.02 mm. Notoixys hirsuta gen. et sp. nov. has an inner coxal seta only on leg 1, as in N . planiceps gen. et sp. nov. (see below). However, unlike the latter species, N . hirsuta gen. et sp. nov. possesses more teeth on the medial margin of the mandibular coxal gnathobase, 2 setae (vs. 1 in N . planiceps gen. etsp. nov. ) onthebasisof themaxillule, and has obscurely segmented rami on the posterior swimming legs, although there are more setae on these rami.