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

description: Bathycopola brevicaudata gen. et sp. nov.   
(Figs. 16, 17)  
 Type material. Holotype ♀ (MNHN-IU-2018-1946, dissected and mounted on a slide) from Bathystyelçẚdes enderbyanus (Michaelsen, 1904) (MNHN-IT-2008-1439 = MNHN S1 / BAT.B/24); West Atlantic, DEMERABY cruise, RV “Jean Charcot”, Stn CP 08 (10°25.10’N, 46°46.90’W), depth 4850 m, 01 September 1980.   
 Etymology. The name is derived from the Latin brev (=short) and caud (=the tail), referring to the short urosome of the new species.   
 Description of female. Body (Fig. 16A, B) stout, pupa-shaped. Body length 1.15 mm; maximum width 386 μm across fourth pedigerous somite. Prosome 5-segmented, occupying most of body length; cephalosome 204×364 μm, slightly wider than first and second pedigerous somites; dorsal cephalic shield well-developed. First to third pedigerous somites each bearing thin tergite; tergite of fourth pedigerous somite extended posteriorly, covering most of urosome, with rounded posterior margin in dorsal view (Fig. 16A), but obliquely tapering in lateral view (Fig. 16B). Urosome (Fig. 16C) small, about 355 μm long, gradually narrowing posteriorly, 5-segmented but first segment (fifth pedigerous somite) very short, obscure. Genital somite wider than long, bearing small copulatory pore proximally on ventral surface. Caudal ramus (Fig. 16D) about 2.8 times longer than wide (76×27 μm); armed with 3 spines and 3 setae (1 seta on outer margin, 1 seta on subdistal inner side, and 1 seta and 3 spines distally); outer margin seta longest, half as long as caudal ramus; innermost of 3 distal spines much smaller than other 2.   
Rostrum as short, blunt anterior prominence on cephalosome. Antennule (Fig. 16E) slender, 220 μm long, 6- segmented; armature formula 2, 8, 3, 6+aesthetasc, 2+aesthetasc, and 11+2 aesthetascs; second segment subdivided into 3 and 5 setae regions; setae thin and generally long; aesthetascs small, confusable with setae. Antenna (Fig. 16F) 3-segmented, consisting of basis and 2-segmented endopod; basis broadening distally, 59×45 μm, armed with 1 elongate spine (56 μm long) distally and bearing few spinules in distal region; first endopodal segment 55×32 μm with 1 seta on inner margin; second endopodal segment about 2.5 times longer than wide (45×18 μm); armed with 2 middle and 4 distal setae plus slender terminal claw, 0.8 times as long as segment.  
Labrum (Fig. 16G) short but broad, with pair of bicuspid processes on posteroventral surface. Mandible (Fig. 16H) consisting of coxa and palp: coxal gnathobase bearing 1 distal tooth and several spinule-like denticles along medial margin; palp biramous, armed with 3 setae on basis, 4 on exopod, and 6 on endopod; endopod articulated from basis but exopod not demarcated from basis; setae on exopod feebly pinnate, other setae naked. Maxillule (Fig. 16I) consisting of precoxa and palp; precoxa bearing 9 setae on arthrite; palp consisting of basis, exopod and endopod; armed with 6 setae on basis, 2 on exopod, and 3 on endopod; exopod and endopod not articulated from basis; 1 additional seta present between arthrite and basis. Maxilla (Fig. 17A) 3-segmented; large syncoxa bearing 2 endites each tipped with 1 seta; basis with claw plus 3 setae; endopod small, bearing 5 setae. Maxilliped (Fig. 17B) as tapering lobe bearing 7 setae and 3 rows of spinules.  
Legs 1-4 (Fig. 17 C-F) biramous with 2-segmented rami. Inner seta on coxa present only in leg 4. First endopodal segment of legs 1-4 unarmed. In legs 3 and 4, outer spine of first exopodal segment and distal spine of second exopodal segment markedly elongated (longer than exopod). Most of spines on rami spinulose distally. Exopods and endopods of legs 2-4 with same armature formula, as follows:  
     Coxa  Basis  Exopod  Endopod      Leg 1  0-0  1-I  I-0; III, I, III  0-0; I, II, I      Legs 2 & 3  0-0  1-0  I-0; III, I, III+1  0-0; I, II, I+1      Leg 4  0-1  1-0  I-0; III, I, III+1  0-0; I, II, I+1      
Leg 5 (Fig. 17G) consisting of lamellate protopod and small exopod; protopod as long as urosome, covering almost entire dorsal surface of urosome (Fig. 16A, B), bearing 1 small seta on distal margin; exopod 2.18 times longer than wide (98×45 μm), armed with 6 unequal setae (1 on ventral margin and 5 distally). Leg 6 not examined.  
 Male. Unknown.   
 Remarks. The diagnostic features of Bathycçpçla brevẚcaudata gen. et sp. nov. are; (1) the dorsal tergite of the fourth pedigerous somite extends posteriorly to cover most of the urosome; (2) the maxillary endopod is 1-segmented and armed with five setae; (3) the second exopodal segments of legs 2-4 are each armed with 7 spines and 1 seta; (4) the second endopodal segments of legs 2-4 are each armed with 4 spines and 1 seta; and (5) the inner coxal seta present only in leg 4. These diagnostic features serve to distinguish the new species from its congeners.
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 32, DOI: 10.11646/zootaxa.4978.1.1, http://zenodo.org/record/4820443