Doropygus kerguelensis Schellenberg 1922
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Doropygus
Doropygus kerguelensis

description: Doropygus kerguelensis Schellenberg, 1922
(Figs. 211–213)
Material examined. 2 ♀♀ (MNHN-IU-2018-1850) and 1 dissected ♀ from Molgula sp., Subantarctic (49°14 Ń, 67°48 É), depth 202-208 m, 21 September 2010; 12 ♀♀ (MNHN-IU-2018-1851) and dissected 3 ♀♀, 1 ♂ from Ascidia meridionalis Herdman, 1880, Subantarctic (48°48 Ń, 70°09 É), depth 103-104 m, 04 September 2010; 1 ♀, 1 ♂ (MNHN-IU-2018-1852) and 1 dissected ♀ from Molgula macquariensis Kott, 1954, Kerguelen MD 04 Stn A3D6; 1 ♀, 2 ♂♂ (MNHN-IU-2018-1853) from M. macquariensis, Kerguelen; 1 ♀, 1 ♂ (MNHN-IU-2009-5183) and 1 dissected ♀ from M. pedunculata Herdman, 1881, POKER III, Stn CE06-049B = 31 (48°430 Ś, 67°585 É), depth 212 m; 1 ♀ (MNHN-IU-2009-5154) and 1 dissected ♀ from M. pedunculata, POKER III, Stn 133 (46°935 Ś, 68°820 É), depth 665 m = 665-706 m; 5 ♀♀, 5 ♂♂ (MNHN-IU-2009-5185) and dissected 1 ♀, 1 ♂from Molgula sp., POKER III, Stn CE06.163 = 167 (51°88 Ś, 70°675 É), depth 382 m; 11 ♀♀, 6 ♂♂ (MNHN-IU-2009-5186) from Molgula sp., POKER III, Stn CE06.048 = 30 (48°397 Ś, 67°338 É), depth 385 m; 15 young ♀♀, 30 ♂♂ (MNHN-IU-2009- 5187) and 1 dissected young ♀ from Molgula sp., POKER III, Stn CE06-039A (47°986 Ś, 67°154 É), depth 487 m; 2 ♀♀ (MNHN-IU-2009-5715) from Molgula pedunculata, POKER III, Stn CE 06-133; 1 ♀, 3 ♂♂ (MNHN-IU-2009-5717) from Molgula sp., POKER III, Stn CE06-119 (46°224 Ś, 68°600 É), depth 165 m; 37 ♀♀, 3 ♂♂ (MNHN-IU-2009-5718) from M. pedunculata, Expedition MD 03, Navire Oceanographique “Marion Dufresne”, Stn 2-7- CB 02 (49°33 Ś, 70°47 É), depth 130 m, 04 April 1974; 12 ♀♀ (MNHN-IU-2009-5719) from M. pedunculata, MD 42/ SIBEX, Stn 001, Mola 251 (51°15.0 Ś, 71°41.2 É), depth 285 m, 12 January 1985; 8 ♀♀, 8 ♂♂ (MNHN-IU-2009-5720) from Molgula sp., POKER III, Stn CE06-059 (48°606 Ś, 67°44 É), depth 220 m; 1♀, 8 young ♀♀, 10♂♂ (MNHN-IU-2009- 5721) from M. pedunculata, POKER III, Stn CE 06-040 = 25 (48°751 Ś, 67°010 É), depth 331 m; 4 ♀♀, 12 ♂♂ (MNHN-IU-2009-5729) from M. pedunculata, MD 42/ SIBEX, Stn.?, MolA 251 (51°15.0 Ś, 71°41.2 É), depth 285 m, 12 January 1985; 4 ♀♀, 12 ♂♂ (MNHN-IU-2009- 5730) from M. pedunculata, Pridz Bay, Stn 22-CP70, (67°000 Ś, 73°372 É), depth 490 m.
Supplementary description of female. Body (Fig. 211A)narrow,slightlydepressed,3.85mmlong.Metasome obscurely 4-segmented with fourth pedigerous somite forming bulbous brood pouch, largely incorporating fifth pedigeroussomite. Freeurosome (Fig. 211B) slender, 5- segmented: genital somite 160×364 μm, shorter than other urosomites; 4 abdominalsomites 314×345, 258×308, 215×258, and 185×234 μm, respectively. Caudalramus (Fig. 211C) elongate, about 6.3 timeslongerthan wide (406×65 μm) and about twice as long as anal somite; armed with 6 small setae; all caudal setae shorter than width of caudal ramus; 2 proximal setae located at 26 and 65% of ramus length.
Coxa Basis Exopod EndopodLeg 10-11-II-1; I-1; III, I, 40-1; 0-1; 1, 2, 3Legs 2 & 30-11-01-1; 1-1; 3, 1, 50-1; 1, 2, 5Leg 40-11-01-0/1; 1-1; 3 0-1; 1, 2, 4(or 2), 1, 5
Rostrum (Fig. 211D) longerthanwide, tapering towardsroundedapex. Antennule (Fig. 211E) 440 μm long, 9-segmented; proximal segments weakly expanded; armatureformula 3, 17, 6, 4+aesthetasc, 4, 3+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; mostof largesetaepinnate with setules perpendicular to long axis of seta. Antenna (Fig. 211F) slender, 4 segmented; shortcoxa unarmed; basis about twice as long as wide, with small (exopodal) knob tipped by 2 vestigial setae at outer distal corner and 1 small seta at inner distal region; first endopodal segment 1.5 times longer than wide, with 1 seta on inner margin; compound distal endopodal segment twice as long as first and4.4 times longerthan wide (180×41 μm); armed with 10 small setae (3 distal setae blunt at tip) and ornamented with minute spinules on outer margin; terminal claw small, less than half length of segment.
Labrum (Fig. 211G) densely setulose posteriorly and with large setulose posteromedian lobe. Mandible (Fig. 211H) with 5 teeth on coxal gnathobase; basis with 1 seta onmedial margin; exopod 4-segmented with 1, 1, 1, and 2 setae on first to fourth segments, respectively, distalmost seta slightly shorter than other 4; first endopodal segment fused with or indistinctly articulated from basis and armedwith 4 setae medially; ornamented withrow of spinules at outer distal corner and patch of minute spinules ventrodistally; second endopodal segment with 10 setae. Maxillule (Fig. 211I) with 9 setaeon arthrite, 1 on coxal endite, 2 on epipodite, 3 on basis, 4 on exopod and 3 on endopod. Maxilla (Fig. 212A) 5-segmented; syncoxa with 3, 1, 2, and 3 setae on first to fourth endites, respectively; basiswith 3 setae; endopodwith 1, 1, and 4 setae on first to third segments, respectively; 2 of 4 setae on third endopodal segment naked, one half length of other. Maxilliped (Fig. 212B) unsegmented, armedwith 9 medial setae and 2 apical setaeon short, narrow distal part; oramented with tuft of setules proximally.
Leg 1 (Fig. 212C) with 3-segmented rami; innerdistal spine on basis 90 μm long, extending to distal border of second endopodal segment; outer margin of first exopodal segment slightly notched at distal third; first outer spine of exopod 88 μm long, twice as long as second and third outer spines. First exopodal segment of leg 4 lacking inner seta in some specimens; third exopodal segment armed with 9 or occasionally 8 setae (in case of 8 setae, first outer seta may be lost, this seta indicated by an arrowhead in Fig. 212E). Armature formula for legs 1–4 as follows:
Leg 5 (Fig. 212F) with broad protopod bearing extremely thin outer seta and row of spinules at inner distal corner; free exopodal segment about 2.6 times longerthan wide (179×69 μm), armedwith 1 short seta and 1 longer seta distally and ornamented with 4 rows of minute spinules on dorsomedial surface.
Descriptionofmale. Body (Fig. 213A) slender, 1.98 mm long. Cephalosome much broader than remaining part of body. Urosome 6-segmented: first to third free abdominal somites longer than wide; other 3 urosomites widerthan long. Caudal ramus about 6.4 times longer than wide (212×33 μm) and 2.2 timeslongerthan anal somite.
Rostrum, antennule, antenna, and all mouthparts as in female. Armature formula for legs 1–3 also as in female. First exopodal segment of leg 4 (Fig. 213B) with or without inner seta, as in female; third exopodal segment of leg 4 with 8 setae (formula 2, 1, 5).
Leg 5 (Fig. 213C) armed and ornamented as in female. Exopodal segment about 3.2 timeslongerthan wide (92×29 μm). Leg 6 represented by 2 naked setae on genital operculum.
Remarks. Doropygus kerguelensis was originally described as D. trisetosus var. kerguelensis (Schellenberg, 1922) but later raised to species level (Sewell, 1949; Illg, 1958). The key features of Schellenberg’s brief description included the following: (1) the caudal ramus is twice as long as the anal somite; (2) the fifth seta on the mandibular exopod is shorter than the fourth; (3) the endopod of the maxillule bears 3 setae; (4) the first outer seta on the exopod of leg 1 is twice as long as the second and third; (5) the second and third outer setae on the exopods of legs 2–4 are about twice as long as the third exopodal segment; (6) the free exopodal segment of leg 5 is 2.5 timeslongerthan wide and has 4 indentations on the inner margin.All of these features are exhibited by our examined specimens, which are therefore identified as D. kerguelensis.
It is interesting to note that the basis of the antenna carries a small knob tipped with 2 vestigial setae at its outer distal angle. This structure is here interpreted as a vestige of the antennal exopod. Asimilar structure is present in the same position on the distal margin of the basis in D. globosus, although it somewhat resembles a bifurcate seta.
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 319-323, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138