Phyllodelphys capensis, 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 : 625-627

Phyllodelphys capensis gen. et sp. nov.

( Figs. 423 , 424 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21446 ) , paratypes (4 intact ♀♀, MNHN-IU-2014- 21447), and dissected paratypes (2 ♀♀, figured) from Trididemnum sp., southwest of Cape Town, South Africa, intertidal, Monniot coll., 05 February 1996.

Etymology. Thetype locality, Cape Town, provides the specific name of the new species.

Description of female. Body ( Fig. 423 A-C) vermiform; body length 4.70-5.09 mm; body length of dissected specimen ( Fig. 423B ) 4.72 mm. Body width variable, narrow in non-ovigerous young adult ( Fig. 423A ), 1.19 mm in dissected ovigerous specimen ( Fig. 423B ), and muchwider, 1.80 mm, infemalewithexpanded brood pouch containing nauplii. Prosome divisible by constrictionintocephalosomeandmetasome:cephalosome ( Fig. 423D, E ) much narrower than metasome. Metasome divisible into short, narrower anterior part (possibly repesenting first pedigerous somite) and longer, broader remaining part. Metasome of expanded specimen ( Fig. 423C ) with 2 constrictions. Freeurosome ( Fig. 423F ) small, graduallynarrowing posteriorly; consistingof short genital somite bearing copulatory pore on ventral surface and unsegmented abdomen, wider than long (260×320 μ). Caudal rami ( Fig. 423 G-I) vestigial, bearing 5 minute setae of variable size.

Rostrum ( Fig. 423D ) broadened distally. Antennule ( Fig. 423J ) lobate, aslongas wide, unsegmented, with indentation subdistally on dorsal margin, apparently unarmed, but ornamented with many short, thick setules on distal region. Antenna ( Fig. 423K ) 3-segmented, consistingof unarmed coxa and basis and unsegmented endopod; endopod distinctly narrower than proximal segments, about 3.1 timeslongerthan wide (80×26 μm), with minute spinules on margins: armed with 7 small setae (1 subdistal and 6 distal) plus short terminal claw, one-thirdaslongas endopod, almost straight.

Mouthparts positioned deep inside pre-oral cavity formed by anterior and posterior folds on ventral side of cephalosome ( Fig. 423D ). Labrum ( Fig. 424A ) smooth, unornamented, with broadly convex posterior margin. Mandible ( Fig. 424B, C ) consisting coxa and biramous palp: coxa ( Fig. 424C ) with broad gnathobase bearing 1 acutely pointed and 3 blunt teeth along distal third of medial margin and with remaining part of medial margin pectinate (spinulose); palp ( Fig. 424B ) consistingof basis, 2-segmented exopod, and unsegmented endopod; basis with 1 setaat mediodistal corner; exopod small, armed with 2 setae on each segment; endopod much larger than exopod, armed with 5 setae; setae on palp broad, but feebly pinnate. Maxillule ( Fig. 424D ) unsegmented, lobate, bearing 9 broad setae: 2 setae on medial margin, 4 leaf-like setae on distal margin, and 3 setaeon outer margin. Maxilla ( Fig. 424E ) 2-segmented; first segment (syncoxa) bearing 2 setae medially; secondsegment (basis + endopod) bearing 4 setae (1 largeand 3 small) medially and bilobed distal part; each distal lobe tipped with 1 small spinule. Maxilliped ( Fig. 424F ) lobate, bearing 4 leaf-like setae of different sizes, 2 larger distal and 2 smaller subdistal setae.

Legs absent.

Male. Unknown.

Remarks.Thefunctionalsignificanceoftheflattened, leaf-like setae found on the maxillule and maxilliped is unknown.

Figures

FIGURE 423. Phyllodelphys capensis gen. et sp. nov., female. A, habitus of young adult, dorsal; B, habitus of ovigerous adult, dorsal; C, habitus of expanded adult containing nauplii, dorsal; D, anterior part of prosome, ventral; E, anterior part of prosome, left; F, urosome, ventral; G, H, I, caudal rami; J, antennule; K, antenna. Scale bars: A–C, 0.1 mm; D, E, 0.2 mm; F, 0.1 mm; G–I, 0.02 mm; J, K, 0.05 mm.

FIGURE 424. Phyllodelphys capensis gen. et sp. nov., female. A, labrum; B, mandibular palp; C, mandibular gnathobase; D, maxillule; E, maxilla; F, maxilliped. Scale bars: 0.02 mm.