Ammonixys quadridens Kim & Boxshall 2020, gen. etsp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Ammonixys
Ammonixys quadridens

description: Ammonixysquadridens gen. etsp. nov.
(Figs. 361, 362)
Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21404) from Polyclinum isipingense Sluiter, 1898 (MNHN-IT-2008-XXX = MNHN A1/POL.B/108), ATIMOVATAE TR07, Madagascar (25°01 Ś, 47°00 É), depth 12-16 m, MNHN coll., 01 May 2010.
Etymology. The specific name is from the Latin quadr (=four) and dens (=tooth), referring to the presence of four teeth on the coxal gnathobase of the mandible.
Descriptionoffemale. Body (Fig. 361A, B)globular, greatly swollen: body length 1.12 mm from frontal margin of cephalosome to posterior margin of fourth pedigerous somite. Prosome with smooth surface; lateral margins of dorsal cephalic shield expanded ventrally, completely concealing mouthparts in lateral view. Metasome 4- segmented; first and second articulations complete, third articulation incomplete; first to third pedigerous somites much wider than long, Fourth pedigerous somite greatly expanded, spherical, 785×774 μm. Freeurosome (Fig. 361C) small, stout, 5-segmented, inserted into ventral surface of brood pouch (Fig. 361B). All urosomites much widerthan long; 4 abdominal somitessparsely ornamented with minute spinules. Caudal ramus (Fig. 361C) small, lobate, slightly longerthan wide, not articulated from anal somite, bearing minute setules; caudal setae apparently absent.
ProtopodExopodEndopodLeg 10-0; 0-01-0; 1-0; 1, 1, 40-0; 0-0; 4Leg 20-01-0; 0-0; 3, 1, 50-0; 0-0; 0, 2, 2Leg 31-00-0; 0-0; 1, 0, 40-0; 0-0; 0, 2, 2Leg 40-00-0; 0-0; 1, 1, 40-0; 0, 2, 1
Rostrum (Fig. 361E) distinct, slightly longerthan wide (84×72 μm), tapering to narrow apex. Antennule (Fig. 361F) archedposteriorly, 117 μmlong, 6-segmented; third and fourth segments articulated from each other only on one surface; first segment with 2 setae; setation of other segments obscure due to similarity with setules; third, fifth and terminal segments each bearing 1 small aesthetasc. Antenna (Fig. 361G) stout, 4-segmented; coxa, basis, and first endopodal segment unarmed; basis shorter than first endopodal segment; narrower second endopodal segment about 2.3 times longer than wide (41×18 μm) and as long as first segment: armed with 3 small setae plus small terminal claw, about one-third as long as second endopodal segment.
Labrum (Fig. 361H) simple, unornamented, with short,broadposteromedian lobe.Mandible (Fig.361I) with coxal gnathobase bearing 4 teeth on distal half of medial margin and pectinate proximal half of medial margin: palp consisting of basis and 2-segmented endopod; basis with 1 seta mediodistally; exopod completely fused with basis, represented by outer lobe of basis and pair of large setae at base of lobe; endopod 2-segmented, incompletely articulated from basis, with 1 broad seta on first segment and 4 setaeon second. Maxillule (Fig. 362A) armedwith 6 setae on arthrite, 1 on coxal epipodite, 1 on basis, 4 on exopod and 3 on endopod; coxal endite absent. Maxilla (Fig. 362B) 4-segmented; syncoxa bearing 2 endites, with 3 setae on first endite and 2 on second; basis with strong claw plus 1 seta; small endopod with 1 seta on first segment and 3 setaeon second. Maxilliped (Fig. 362C) as small lobe bearing 4 setae.
Legs 1–4 (Fig. 362 D-G) biramous with 3-segmented exopods; endopods 3-segmented inlegs 1–3, but 2- segmented in leg 4. Protopod 2-segmented in leg 1, but unsegmented in legs 2–4. Inner coxal seta absent in legs 1–4. Leg 1 lacking innerdistal element on basis. Outer seta on basis present only in leg 3. Endopod of leg 1 strongly curved inwards. First exopodal segment of legs 3 and 4 and second exopodal segment of legs 2 and 4 each bearing spiniform outer distal process. Outer setae on third exopodal segment of legs 2–4 vestigial. Armature formula for legs 1–4 as follows:
Leg 5 (Fig. 361C) consisting of outer lobe tipped with 1 small seta and inner, tapering, sclerotized process; left and right inner processes interconnected.
Male. Unknown.
Remarks.Itisnoteworthythat Ammonixysquadridens gen. et sp. nov. was extracted along with Doroixys obesa sp. nov. and two other species of copepods (Scolecodes sp. and Haplostoma sp.), all from the same ascidian host.
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 pages 541-542, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138