Janstockia clavelinae, 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 : 614

Janstockia clavelinae sp. nov.

( Figs. 415 , 416 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21441 ) anddissectedparatype (♀, figured) from Clavelina fecunda (Sluiter, 1904) , AURACEA 1995, south of Matemo, Ibo, Mozambique, depth 15 m, Monniot coll., 17 November 1995.

Etymology. The new species is named after Clavelina , the generic name of the type host.

Descriptionoffemale. Body ( Fig. 415A ) vermiform, elongate, cylindrical; consistingof cephalosome, long metasome and short abdomen; body length 6.65 mm. Cephalosome ( Fig. 415B, C ) defined but not articulated from metasome; width 0.66 mm, length 0.47 mm, with paired expanded ventral folds covered with ornamentation of minutesetules. Metasomewithweaklateralconstriction between first pedigerous somite and remaining part ( Fig. 415B ): distances between 4 leg pairs 0.32, 1.14, and 2.42 mm, respectively and distance from leg 4 to posterior margin of abdomen 2.21 mm. Fifth pedigerous and genital somites incorporated into metasome; copulatory pore present on posteroventral surface ( Fig. 415E ). Abdomen ( Fig. 415D ) 157×173 μm, unsegmented, bilobed posteriorly, defined from metasome by dorsal suture line, but lacking any suture line ventrally ( Fig. 415E ). Caudal rami not defined; 6 small caudal setae present on apex of each posterior margin lobe ( Fig. 415E ).

Rostrum ( Fig. 415F ) small and tapering, with narrower apical part. Antennule ( Fig. 415G ) strongly tapering, indistinctly 3-segmented, ornamented with setules on first and second segments; first segment longer than remaining part; armature formula 0, 2+aesthetasc, and 9+2 aesthetascs. Antenna ( Fig. 416A ) stout, 3- segmented; first segment (coxa) very broad and short, unarmed; secondsegment (basis) widerthan long, unarmed; terminal segment (endopod) produced into distal claw, armed with 4 small setae near middle.

Labrum ( Fig. 415H ) small, semicircular. Mandible ( Fig. 416B ) as elongate lobe bearing 3 setae distally. Maxillule ( Fig. 416C ) broad, distally bilobed, and armed with 5 broad, plumose setae (1 on narrow outer lobe and 4 on broad inner lobe). Maxilla absent. Maxilliped (third mouthpart) ( Fig. 416D ) 2-segmented, unarmed, covered with setules; proximal segment tapering; distal segment with tapering distal tip.

Legs 1–4 wider than long, biramous with obscurely segmented protopods and unsegmented rami; coxa unarmed, but basis with pinnate outer seta. Leg 1 ( Fig. 416E ) with patches of fine spinules on ventral surface of coxa and inner ventrodistal surface of basis; exopod with claw-like process and 8 small setae; endopod smaller than exopodwith 6 smallsetae. Leg 2 ( Fig. 416F ) withrow of fine spinules on ventral surface of coxa; basis smooth; exopod with strong, claw-like process and 8 small setae; endopod with 9 small setae. Leg 3 shaped and armed as in leg 2. Leg 4 also shaped as leg 2, except bearing 7 setae on both rami.

Leg 5 ( Fig. 415E ) represented by pair of small setae on ventral surface of metasome.

Male. Unknown.

Remarks. Two species are currently known in the genus Janstockia : J. phallusiella from the Suez Canal and Red Sea ( Boxshall & Marchenkov, 2005; Kim I.H. et al., 2016), and J. truncata Kim I.H. & Moon, 2011 from Korea (Kim I.H. & Moon, 2011). In these two species, the trunk bears a pair of lateral wing-like expansions on the first pedigerous somite (such wing-like expansions are absentin J. clavelinae sp. nov.), the basis of leg 1 bears a broad inner distal seta which is absent in J. clavelinae sp. nov., the mandible is armed with 7 setae compared with 3 setae in J. clavelinae sp. nov., the maxillule is armed with 6 or 7 setae (cf. 5 setaein J. clavelinae sp. nov.) and some of these setae expanded and globular (cf. all setae attenuated in J. clavelinae sp. nov.). These differences allow J. clavelinae sp. nov. to be readily differentiated from its two congeners.

Figures

FIGURE 415. Janstockia clavelinae sp. nov., female. A, habitus, ventral; B, anterior part of body, dorsal; C, cephalosome and leg 1, ventral; D, abdomen, dorsal; E, posterior end of body, ventral; F, rostrum; G, antennule; H, labrum. Scale bars: A, 0.5 mm; B, 0.2 mm; C–E, 0.1 mm; F, H, 0.05 mm; G, 0.02 mm.

FIGURE 416. Janstockia clavelinae sp. nov., female. A, antenna; B, mandible; C, maxillule; D, maxilliped; E, leg 1; F, leg 2. Scale bars: A, E, F, 0.02 mm; B–D, 0.01 mm.