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 Mecodelphys gen. nov. Diagnosis . Body Doropygus -like. Prosomal somites divided only by weak constrictions; third and fourth pedigerous somites fused, forming inflated brood pouch. Free urosome clearly 5-segmented, inserted into ventral side of brood pouch. Caudal ramus armed with small setae. Rostrum well-developed. Antennule incompletely segmentedwith reduced setation. Antenna 3-segmented with small terminal claw. Labrum distinct. Mandible consistingof biramous palp only; exopod and endopod fused to basis, lobate, unsegmented, each armed with 4 setae. Maxillule, maxilla and maxilliped each represented by single lobe bearing 1 to few setae. Legs 1–4 biramous with extremely long, unsegmented rami; setation reduced. Leg 5 represented by 2 processes each bearing 1 seta. Type and only species . Mecodelphys edentatus gen. et sp. nov . by original designation. Etymology . The generic name is derived from the Greek meco (=long) and - delphys (a common ending for genera in the family) and refers to the elongate swimming legs of the new genus. Gender masculine. Remarks . The body of Mecodelphys gen. nov . is similar to that of Doroixys , but its mouthparts and legs are entirely different from those of Doroixys and the other genera in the Doroixys -group. Although the characteristically elongate and unsegmented rami of legs 1–4of Mecodelphys gen. nov . are sharedby Unimeria gen. nov . , they display several other important morphological differences. In Mecodelphys gen. nov . the urosome is distinctly 5-segmented whereas it is unsegmented in Unimeria gen. nov . The mandible of Mecodelphys gen. nov . lacks the coxal gnathobase and its exopod and endopod are both fused to the basis whereas the mandible of Unimeria gen. nov . has a pectinate coxal gnathobase and has a free exopod and endopod. The maxilliped is present in Mecodelphys gen. nov . but absent in Unimeria gen. nov . , and leg 5 is present in Mecodelphys gen. nov . but absent in Unimeria gen. nov .