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 Scolecodesrectus sp. nov. ( Figs. 408 , 409 ) Type material . Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21438 ) from Boltenia hirta Monniot C. & Monniot F., 1977 (Type MNHN-IT-2008-1485 = MNHN S2/BOL.A/7), SW of Heard Island ( 55°49.5’S , 69°35.7’E ), depth 4200-4225 m , MNHN coll., 11 April 1974 . Etymology . The name is derived from the Latin rect (=straight), alluding to the linear body of the female of the new species. Descriptionoffemale . Body ( Fig. 408A ) elongate, cylindrical, straight, consisting of prosome and small unsegmented abdomen: bodylength 6.21 mm; maximum body width 0.86 mm in middle of prosome. Cephalosome ( Fig. 408B ) small, articulated from metasome, narrowing anteriorly. Metasome with 4 original pedigerous somites defined by incomplete dorsal sutures.Anteriorpart of body from rostrum tolevel of leg 4 occupying about 30% of total body length; legs 1–4 separated by equal intervals. Fourth pedigeroussomiteexpandedposteriorly, incorporatingfifth pedigerous somite and forming brood pouch. Copulatory pore positioned on posteroventral surface of incorporated genitalsomite. Abdomen ( Fig. 408C ) small, unsegmented, longerthan wide (216×180 μm), not articulated from prosome, inserted into posteroventral surface of prosome. Caudal rami ( Fig. 408D ) about 2.8 times longerthan wide (125×45 μm), tapering in distal half, ornamented with scattered papillae: armed with 6 smallsetae (2 outer lateral plus 4 distal and subdistal). FIGURE 408. Scolecodes rectus sp. nov . , female. A, habitus, right; B, anterior part of prosome, dorsal; C, urosome, ventral; D, right caudal ramus, ventral; E, antennule; F, antenna; G, labrum and paragnaths; H, mandible; I, maxillule. Scale bars: A, 1 mm; B, C, 0.1 mm; D–I, 0.02 mm. FIGURE 409. Scolecodesrectus sp. nov . , female. A, maxilla; B, leg 1; C, leg 2; D, leg 3; E, leg 4. Scale bars: A, 0.02 mm; B–E, 0.05 mm. Rostrum ( Fig. 408B ) directed anteriorly, tapering. Antennule ( Fig. 408C ) unsegmented, consistingof greatly expanded, globular proximal part and narrow, digitiform distal part; armed with 4 setae on proximal part and about 8 setaeon distal part. Antenna ( Fig. 408F ) 3-segmented, consistingof short coxa, broad basis, and unsegmented endopod; basis slightly longerthan wide; endopod tapering, terminating in claw and bearing 1 outer and 4 inner smallsetae at base of claw. Labrum ( Fig. 408G ) simple, with slightly produced mid-region of free posterior margin. Mandible with coxa represented by setulose lobe ( Fig. 408G ); palp forming rectangular lobe ( Fig. 408H ) bearing 3 large naked setae distally on medial margin and 3 small pinnate setae plus 1 pointed, setiform process on distal margin. Maxillule ( Fig. 408I ) lobate, bearing 7 pinnate setae (3 large setae on medial margin and 4 smaller, apical or subapical setae). Maxilla ( Fig. 408A ) lobate, unsegmented, armed distally with 3 naked setae. Maxilliped absent. Legs 1–4 ( Fig. 409 B-E) biramous, each consisting of unsegmented protopod, 2-segmented exopod and 1- segmented endopod. Protopods armed with outer seta (derived from basis) only. Both rami obscurely defined from protopod; all setae naked, most spiniform, short but thick, with nipple-like tip. Armature formula for legs 1–4 as follows:
Protopod Exopod Endopod
Leg 1 1-0 1-0; 8 7 or 8
Leg 2 1-0 1-0; 11 10 or 11
Leg 3 1-0 1-0; 11 10
Leg 4 1-0 1-0; 11 or 12 10 or 13
Leg 5 absent.
Male . Unknown. Remarks . Scolecodes rectus sp. nov . shares the possession of 2-segmented exopods on legs 1–4 only with S . pugetensis sp. nov . Thischaracterstate distinguishesthe new species from the type species, S. huntsmani . It differs from S . pugetensis sp. nov . as follows: the abdomen is longer than wide (vs. as long as wide in S . pugetensis sp. nov . ), the mandible carries a setiform apical process in addition to 6 setae (vs. no setiform process in S . pugetensis sp. nov . ), the maxillule is armed with 7 setae (vs. 6 setae in S . pugetensis sp. nov . ), the maxilla is armed with 3 setae (vs. 4 setae in S . pugetensis sp. nov . ), and the rami of legs 1–4 are armed with fewer setae.