Schizoproctus fijiensis Kim & Boxshall 2021, sp. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Cyclopoida
Ascidicolidae
Schizoproctus
Schizoproctus fijiensis

description: Schizoproctus fijiensis sp. nov.   
(Figs. 79, 80)  
 Type material. Holotype ♀ (MNHN-IU-2018-1983, dissected and mounted on a slide) from Culeçlus recumbens Herdman, 1881 (MNHN-IT-2008-2479 = MNHN S2 / CUL/47); Ride de Lau, Fiji, BORDAU 1 cruise, RV “Alis”, Stn CP 1415 (16°31´S, 179°00´W), depth 670-682 m, Bouchet, Warén & Richer-IRD coll., 27 February 1999.   
 Etymology. The name of the type locality provides the name of the new species.   
 Description of female. Body (Fig. 79A) dorsoventrally flattened, consisting of broader anterior and narrower posterior parts, with weak exoskeleton. Body length 1.69 mm and maximum width 625 μm across cephalosome. Anterior part distinctly 5-segmented; fifth pedigerous somite completely fused with fourth pedigerous somite. Posterior part of body consisting of genital somite and 4-segmented abdomen. Genital somite much wider than long. Anal somite about 1.4 times longer than wide, twice as long as third abdominal somite. Caudal ramus (Fig. 79B) about 1.3 times longer than wide (81×62 μm), armed with 4 claws and 1 seta, and ornamented with fine spinules ventrally on inner distal surface; lengths of 4 claws 73, 64, 59, and 35 μm from inner to outer, respectively,.   
Rostrum (Fig. 79C) much wider than long, with rounded apex and ornamented distally with minute spinules on lateral margins. Antennule (Fig. 79D) strongly tapering, 5-segmented, but articulation between first and second segments indistinct; armature formula 12, 5, 2, 3, and 8. Left antenna (Fig. 79E) 4-segmented; proximal 3 segments unarmed; terminal segment (second endopodal segment) as long as basis, armed with 8 spines; 3 proximal inner spines as long as segment width; fourth inner spine smallest; second outer spine on distal margin longest, 89 μm long. Terminal segment of right antenna (Fig. 79F) as long as that of left antenna, but armed with 7 spines (lacking small fourth inner spine of left antenna); longest second outer spine on distal margin 86 μm long.  
Labrum (Fig. 79G) weak, flexible, subdivided into wider proximal and thin-walled, semicircular distal parts, with weak dorsal protuberance in middle. Mandible (Fig. 79H) consisting of coxa and palp: coxal gnathobase (Fig. 79I) specialized, with medial margin bearing 9 teeth; distalmost tooth elongate, close to second tooth, thin, bearing fine spinules along proximal margin; second and third distal teeth strong, widely separated from each other; proximal 6 teeth smaller, finely bifid at tip; palp armed with 9 setae arranged as 3, 2, 2, and 2. Maxillule (Fig. 79J) with 8 distinct setae on precoxal arthrite, 1 small seta representing coxal epipodite, 5 setae (2 inner and 3 outer) and prominent distal tubercle on basis, and 3 setae on endopod. Maxilla (Fig. 79K) indistinctly 3-segmented, armed with 3, 3, and 4 setae on first to third segments, respectively; shortest seta on third segment spiniform. Maxilliped (Fig. 80A) robust, consisting of syncoxa, basis, and 2-segmented endopod; syncoxa with 2 large setae on inner side; basis with 2 unequal setae; first endopodal segment short and unarmed; second endopodal segment bearing 2 small setae and 1 spinule; terminal claw completely fused with segment.  
Legs 1-3 (Fig. 80 B-D) and leg 4 biramous with unsegmented rami; coxa unarmed; basis with small outer seta. Endopods tapering, much smaller than exopods. Exopods of legs 1-4 each armed with 6 distinct spines. Leg 4 armed as in leg 3. All setae on endopods pinnate. Armature formula for legs 1-4 as follows:  
     Coxa  Basis  Exopod  Endopod      Leg 1  0-0  1-0  VI  8      Leg 2  0-0  1-0  VI  3      Legs 3 & 4  0-0  1-0  VI  2      
Leg 5 (Fig. 80E) fleshy, lamellate, oval, 404×308 μm, with 2 small and 2 larger setae, 3 located distally and 1 on ventral margin. Leg 6 not observed due to damage to genital somite during dissection.  
 Male. Unknown.   
 Remarks. The medial, cutting margin of the coxal gnathobase of the mandible of Schẚzçprçctus typically bears 3 or 4 distal teeth and has a pectinate proximal part (carrying an array of fine spinules). In contrast, the medial margin of the coxal gnathobase of S. fẚjẚensẚs sp. nov. is armed with 3 distal teeth and a proximal array of 6 bifid teeth. This specialized form of the coxal gnathobase has not been found previously within the family Botryllophilidae and thus serves to characterize S. fẚjẚensẚs sp. nov. Additional diagnostic features of S. fẚjẚensẚs sp. nov. include, (1) the endopods of legs 2-4 are tapering and much smaller than the exopods; (2) the numbers of setae on the endopods of legs 1-4 are 8, 3, 2, and 2, respectively, which is a unique combination within the genus; (3) leg 5 is elliptical; and (4) the two setae on the syncoxa (first segment) of the maxilliped are relatively large, half as long as the width of the syncoxa.
description: Published as part of Kim, Il-Hoi & Boxshall, Geoff A., 2021, Copepods (Cyclopoida) associated with ascidian hosts: Ascidicolidae, Buproridae, Botryllophilidae, and Enteropsidae, with descriptions of 84 new species, pp. 1-286 in Zootaxa 1 on page 123, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/4820443