Notodelphyopsis gemina, Kim & Boxshall, 2020

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), Megataxa 4 (1), pp. 1-6 : 85-86

publication ID

https://doi.org/ 10.11646/megataxa.4.1.1

DOI

https://doi.org/10.5281/zenodo.5661667

persistent identifier

https://treatment.plazi.org/id/03C487CB-EF05-3A6D-FCEF-F98FFC7DF8C4

treatment provided by

Plazi

scientific name

Notodelphyopsis gemina
status

sp. nov.

Notodelphyopsis gemina sp. nov.

( Figs. 55–57 View FIGURE 55 View FIGURE 56 View FIGURE 57 )

Typematerial. Holotype (intact ♀, MNHN-IU-2009- 5191 ) , paratypes (19 intact ♀♀, MNHN-IU-2014-21232) , and dissected paratypes (1 ♀, 1 ♂, figured), from Corella antarctica Sluiter, 1905 , Antarctic Ocean (61°26 Ś, 41°55.4 Ẃ), depth 604 m, Eltanin cruise 12, 12 April 1964. GoogleMaps

Etymology. The specific name is derived from the Latin gemin (=twin), alluding to the close similarity of the new species to Notodelphyopsis illgi .

Descriptionoffemale. Body ( Fig. 55A View FIGURE 55 ) slender, 1.87 mm long. Cephalosome well-defined, but articulations between pedigeroussomites indistinct: first to third pedigerous somites lacking epimera. Brood pouch variable in form; fifth pedigerous somite completely fused to brood pouch. Free urosome ( Fig. 55B View FIGURE 55 ) slender, 4-segmented. Genital double-somite ( Fig. 55C View FIGURE 55 ) 210×149 μm, subdivided dorsally and ventrally by faint, indistinct suture line at anterior third and ornamented with several transverse rows of minute spinules on ventral surface. Three freeabdominal somites 152×131, 135×108, and 115×108 μm, respectively. Caudalramus ( Fig. 55D View FIGURE 55 ) elongate, about 9.3 times as long as wide (325×35 μm) and 2.8 timeslongerthan anal somite, subdivided by constriction at 60% of length; ornamented with dense covering of setules on ventral surface; armed with 6 setae, 4 distal setae pinnate, other 2 naked, outer lateral seta located at 65% of ramus length.

Coxa Basis Exopod Endopod
Leg 1 0-1 1-I I-1; I-1; III, 1, 40-1; 0-1; 1, 2, 3
Legs 2 & 30-1 1-0 I-1: I-1; III, I, 50-1; 0-2; 1, 2, 3
Leg 4 0-1 1-0 I-1; I-1; II, I, 5 0-1; 0-2; 1, 2, 2

Rostrum ( Fig. 55E View FIGURE 55 ) 87×70 μm, spatulate, with nearly parallel lateral margins. Antennule ( Fig. 55F View FIGURE 55 ) slender, elongate, 575 μm long and extending to posterior margin of second pedigerous somite; 9-segmented ( Fig. 30 View FIGURE 30 ), armatureformula 3, 17, 6, 4+aesthetasc, 4, 2, 2, 2+aesthetasc, and 7+aesthetasc; several setae on proximal segments weakly pinnate, others naked (as figured). Antenna ( Fig. 56A View FIGURE 56 ) 4-segmented, consistingof coxa, basis and 2-segmented endopod; coxa short and unarmed; basis with 2 equal, large pinnate setae representing exopod; first endopodal segment with 1 setaon inner margin; compound distal endopodal segment about 4.5 times longer than wide, armed with terminal claw and 11 setae and ornamented with 3 rows of spinules on distal half of outer side; 2 subdistal setae pinnate, others naked; 3 teminal setae blunt at tip; terminal claw small, about one-thirdaslongas segment.

Labrum ( Fig. 55G View FIGURE 55 ) with deeply concave, setulose posterior margin. Mandible ( Fig. 55H View FIGURE 55 ) consisting coxa and biramous palp: coxa with 4 teeth and 1 small seta on gnathobase; distalmost tooth acutely pointed: palp consisting of basis, exopod and 2-segmented endopod; basis with 1 seta and setules on medial margin; exopod 3-segmented, armed with 1, 2, and 2 setae on first to third segments, respectively, 2 distal setae much longerthan other 3; endopod incompletely articulated from basis, with 2 and 10 setaeon first and second segments, respectively, one seta on second segment smalland positionedon dorsal surface. Paragnath ( Fig. 55I View FIGURE 55 ) as lobe bearing semicircular lobule at outer distal corner and setules on medial margin. Maxillule ( Fig. 55J View FIGURE 55 ) with 9 setae (including 2 small) on arthrite, 1 on coxal endite, 2 on epipodite, and 3 on medial margin of basis (proximal seta much smaller than distal 2); exopod with 4 setae distally; endopod incompletely 2-segmented with 2 setae medially on first segment and 4 long, proximally-pinnate setaeon second segment. Maxilla ( Fig. 56B View FIGURE 56 ) 5-segmented; syncoxawith 3+1 small, 1, 2, and 3 setae on first to fourth endites; basis with claw bearing spinules along concave margin, plus 2 setae; endopod with 1, 1, and 3 setae on first to third segments, respectively. Maxilliped ( Fig. 56C View FIGURE 56 ) 3-segmented and armedwith 9 (2 spiniform), 0, and 3 setaeonfirst to third segments, respectively; second segment ornamented with setules along medial margin and patch of spinules distally.

Legs 1–4 with 3-segmented rami. Outer setaon basis of all swimming legs naked ( Fig. 56 View FIGURE 56 D–F). Inner distal spine on basis of leg 1 longer than first endopodal segment, 71 μm long. Armature formula for legs 1–4 as follows:

Leg 5 ( Fig. 56G View FIGURE 56 ) reduced, represented by outer digitiform protopodal process tipped with naked seta and small free exopodal segment also tipped with naked seta.

Description of male. Body ( Fig. 57A View FIGURE 57 ) tapering posteriorly and arched ventrally. Body length 785 μm. Cephalosome with well developed dorsal shield: second to fourth pedigerous somites each with well-developed dorsal tergite. Urosome ( Fig. 57B View FIGURE 57 ) 6-segmented, with free fifthpedigerous somite, genitalsomite 62×86 μm, with row of fine spinules on ventral surface of each genital operculum, and 4 freeabdominalsomites 77×73, 77×73, 69×60, and 51×54 μm, respectively. First abdominal somite ornamented with 3 transverse rows of spinules on ventral surface ( Fig. 57B View FIGURE 57 ). Caudal ramus about 4.8 times longer than wide (72×15 μm); armed with 6 setae, proximal outer lateral seta positioned at middle of ramus.

Rostrum as in female. Antennule ( Fig. 57C View FIGURE 57 ) 10- segmented, non geniculate; segmental fusion pattern I-II, III-XI, XII, XIII, XIV, XV-XVI, XVII, XVIII-XX, XXI-XXIII, XXIV-XXVIII: armatureformula 3, 17, 2, 2, 2, 4+aesthetasc, 1, 3, 2+aesthetasc, and 11+aesthetasc; secondsegment incompletely subdivided proximally with traces of 2 suture lines on posterior surface. Antenna as in female.

Labrum, paragnath, maxillule, and maxilla as in female. Mandible with 9 setae (rather than 10 as in female) on second endopodal segment. Maxilliped ( Fig. 57D View FIGURE 57 ) armed with 7 setae (grouped as 3 and 4) on first segment; second segment with patch of spinules distally asin female. Legs 1–5 asin female.

Remarks. Marchenkov & Boxshall (2003) distinguished Notodelphyopsis illgi ( Marchenkov & Boxshall, 2003) from related species by its slender body shape, elongate antennule, and the extremely elongate caudal rami of the female. Notodelphyopsis gemina sp. nov. shares theseand otherfeatures with N. illgi . The latter species was recorded from the ascidian Corynascidia herdmani Ritter, 1913 living at a depth of 508 m in the North Pacific, whereas N. gemina sp. nov. was found in the Antarctic. Although the two species were found on different hosts and in very different zoogeographic regions, they display very few morphological differences. We note the following differences: (1) the body length of N. illgi is 2.37 mm in the female and 1.25 mm in the male, compared to 1.87 mm in the female and 0.79 mm in the male of N. gemina sp. nov.; (2) the caudal ramus of the female of N. illgi is 4.4 times longer than the anal somite, whereas it is only about 2.8 times longer in N. gemina sp. nov.; and (3) the antennule of the female is 10-segmented in N. illgi , but 9-segmented in N. gemina sp. nov. These differences are sufficient to justify the establishment of a new species.

GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF