Monnioticopa minuta, Kim & Boxshall, 2021

Kim, Il-Hoi & Boxshall, Geoff A., 2021, Copepods (Cyclopoida) associated with ascidian hosts: Ascidicolidae, Buproridae, Botryllophilidae, and Enteropsidae, with descriptions of 84 new species, Zootaxa 1, pp. 1-286 : 254-256

Monnioticopa minuta gen. et sp. nov.

( Figs. 167 , 168 )

Type material. Holotype ♀ (MNHN-IU-2014-21576) and paratype ♀ (dissected, MNHN-IU-2014-21482) from iẚssçclẚnum badẚum Monniot F. & Monniot C., 1996 (MNHN-IT-2008-4913); Papua New Guinea, N tip of Normanby I., pinnacle W of Observation Point , CRCHO 516 , (09°44.59´S, 150°43.01´E), depth 36 m, CRRF coll., 16 January 2002.

Etymology. The name of the new species refers to its relatively small body.

Description of female. Body ( Fig. 167A, B ) relatively small; body length 636 μm; maximum width 192 μm (across third pedigerous somite). Cephalic shield short, more than twice as wide as long (74×164 μm), with indis- tinct posterodorsal margin. Trunk unsegmented with 3 faint transverse sclerotization bands between 4 anterior pedigerous somites; second to fourth pedigerous somites bearing weak tergal folds dorsolaterally, but without ventral interpodal protrusions; fifth pedigerous somite narrower than anterior part of trunk. Genitoabdomen ( Fig. 167C ) 4-segmented; 3 free abdominal somites 25×58, 22×50, and 28×47 μm, respectively, ornamented with many rows of minute spinules on ventral surface. Anal somite with 3 transverse rows of minute spinules on lateral surfaces; anal prominence distinct, with longitudinal row of minute spinules on each lobe. Caudal ramus ( Fig. 167D ) nearly rectangular, nearly twice as long as wide (37×19 μm); ornamented with transverse rows of minute spinules on ventral surface; armed with 1 dorsal seta (25 μm long) at 65% of ramus length, and 4 wart-like, rudimentary setae subdistally on dorsal margin.

Rostrum ( Fig. 167F ) small, semicircular, bearing pairs of sensilla subdistally and proximally. Antennule ( Fig. 167F ) 51 μm long, incompletely 2-segmented; proximal segment armed with 1 seta on anterior margin; distal seg- ment narrower and slightly shorter than proximal segment, armed with 8 setae grouped as 3, 1, and distal 4. Antenna ( Fig. 167G ) elongate, about 42 μm long, digitiform, 3-segmented; distal segment broader than proximal segments, with minute spinules on apical surface.

Labrum ( Fig. 167E ) unornamented; lacking palps. Mandible ( Fig. 167H ) unsegmented, tipped with powerful claw 25 μm long. Maxillule ( Fig. 167I ) bilobed; larger inner lobe tipped with spinulose seta and densely pigmented area along medial side; smaller outer lobe tipped with 1 thin, naked seta. Maxilla ( Fig. 167J, K ) bilobate, with longer inner lobe (endite of syncoxa) tipped with 1 seta; shorter outer lobe with 3 unequal setae (2 distal and 1 subdistal). Maxilliped absent.

Legs 1-4 each consisting of 2-segmented protopod, 2-segmented exopod, and unsegmented endopod; basis with small outer seta. Legs 1, 2, and 4 same in form and armature; distal exopodal segment tipped with small claw and circular element ( Fig. 168A ). Exopod of leg 3 ( Fig. 168B ) with large spiniform process on laterodistal margin. Endopods of legs 1-4 with 2 unequal, naked setae distally; laterodistal seta about 1.5 times longer than mediodistal seta. Mediodistal seta as long as or slightly longer than endopodal segment.

Leg 5 ( Fig. 168C ) lamellate, as long as wide (100×100 μm), narrowed proximally; armed with 2 small setae on distal margin.

Male. Unknown.

Remarks. Mçnnẚçtẚcçpa mẚnuta gen. et sp. nov. is distinguishable from the type species of the genus by the following features: (1) the caudal rami are 1.95 times longer than wide (vs. 1.47 times in the type species); (2) the proximal segment of the antennule is armed with 1 seta (vs. 2 setae in the type species); (3) the coxa of the swimming legs is not expanded (vs. expanded, disc-shaped); (4) the basis of swimming legs 1-4 is armed with an outer seta (vs. unarmed in the type species); and (5) leg 5 narrows proximally (vs. not narrowed).

Figures

FIG. 167. Mçnnẚçtẚcçpa mẚnuta gen. et sp. nov., female. A, habitus, dorsal; B, habitus, right; C, genitoabdomen, ventral; D, anal somite and caudal rami, dorsal; E, cephalic appendages ẚn sẚtu, ventral; F, rostrum and antennule; G, antenna; H, mandible; I, maxillule; J, K, maxillae. Scale bars: A, B, 0.1 mm; C-F, 0.02 mm; G-K, 0.01 mm.

FIG. 168. Mçnnẚçtẚcçpa mẚnuta gen. et sp. nov., female. A, leg 1; B, leg 3; C, leg 5. Scale bars: A, B, 0.02 mm; C, 0.05 mm.