Achelidelphys bifida Kim & Boxshall 2020, sp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Achelidelphys
Achelidelphys bifida

description: Achelidelphys bifida sp. nov.
(Fig. 445)
Typematerial. Holotype ♀ (intact, MNHN-IU-2014- 21471) from Didemnum poecilomorpha Monniot F & Monniot C, 1996 (Type MNHN-IT-2008-3239 = MNHN A2/DID.C/230), CRRFOCDN 1379-J, north of Sulawesi, Indonesia (0l°51.52’N, 125°03.84’E), depth 40 m, 20 May 1993.
Etymology. The species name refers to the biramous leg 4 of the new species
Description of female. Body (Fig. 445A, B) unsegmented, stellate. Body length 2.20 mm measured from anterior margin of cephalosome to distal tip of urosome. Greatest width 1.95 mm between lateral tips of leg 2 exopods. Body surface ornamented with minute setules (Fig. 445C). Urosome (Fig. 445C) present as small lobe at posterior end of body, fused with prosome, bearing 2 small, unequal lobes (probably caudal rami) at posterior margin; caudal setae absent.
Rostrum (Fig. 445B) positioned on ventral surface of cephalosome, digitiform, anteroventrally-directed, tapering, about 3 timeslongerthan wide. Antennules (Fig. 445A, B) as paired tapering anterolateral processes on cephalosome, each with dorsally curved tip. Antennae absent. Labrum (Fig. 445B) as globular, ventrally-directed lobe, positioned between leg 1 pair. Mouthparts absent.
Legs 1–4 biramous (Fig. 445B). Rami of leg 1 subequalin length; exopod directed laterally, curved, slightly broader than endopod; endopod directed ventrally and curved anteriorly. Exopods of legs 2–4 broader than thatofleg 1, tapering, abouttwiceaslongas wide.Exopods of legs 2 and 3 laterally-directed and curved posteriorly. Exopod of leg 4 posteromedially-directed. Endopods of legs 2–4 shorter and narrower than exopods, digitiform, about 3 times longer than wide, laterally-directed in legs 2 and 3, but posteriorly-directed in leg 4. Digitiform midventral processes present between leg pairs 2 and 3 (Fig. 445B). Leg 5 absent.
Male. Unknown.
Remarks. With laterally-directed legs 1–4 and a metasome not extending beyond the insertion of leg 4, the new species belongs to the genus Achelidelphys, as defined by Boxshall & Marchenkov (2007). Within the genus, A. bifida sp. nov. is most closely related to A. steinitzi Lafargue & Laubier, 1977 in having two median ventral processes, one between leg 2 pair and the other between leg 3 pair. However, A. bifida sp. nov. can be differentiated from A. steinitzi and other congeners by the biramous condition of leg 4. Within the Brementia - group of notodelphyids, a biramous leg 4 was previously recordedin the genera Brementia and Pholeterides, as well as in three species of Anoplodelphys (A. corneci Lafargue & Laubier, 1978, A. galli Lafargue & Laubier, 1978, and A. incerta Lafargue & Laubier, 1978). However, all these species possess paired antennae, which are lacking in A. bifida sp. nov.
description: Published as part of Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), pp. 1-6 in Megataxa 4 (1) on page 656, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138