Enterocola neocaledonicus, 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 : 232-235

Enterocola neocaledonicus sp. nov.

( Fig. 152 )

Type material. Holotype ♀ (MNHN-IU-2014-21560), 2 ♀♀ paratypes (MNHN-IU-2014-21561), and 2 ♀♀ para- types (dissected, MNHN-IU-2014-21477) from aẚdemnum lẚgulum Monniot F., 1983; Goelands I., New Caledonia, Stn NC 47, depth 12 m, Thomassin coll., 20 March 1987.

Additional non-type material. 10 ♀♀ (MNHN-IU-2014-21562) in a. lẚgulum; anse Vata , Nouméa, New Caledonia, Stn NC 60, depth 0-3m, Monniot coll., 27 March 1987 .

Etymology. The name of the new species is derived from its type locality, New Caledonia.

Description of female. Body ( Fig. 152A, B ) eruciform, curved dorsally; body length 790 μm in dissected specimen and 556, 691, and 760 μm in 3 other measured specimens; maximum width 260 μm (across first pediger- ous somite). Cephalic shield 142×233 μm, with well-defined posterior margin. Trunk unsegmented, gradually nar- rowing posteriorly; first pedigerous somite bearing dorsal tergite, but second to fourth pedigerous somites bearing well-developed dorsolateral tergal folds. Third pedigerous somite bearing small tubercle mid-dorsally (indicated by arrowhead in Fig. 152A, B ) between left and right dorsolateral tergal folds. First to fourth pedigerous somites each with single, ventral interpodal protrusion between left and right legs, weak in first and second pedigerous somites but well-developed in third and fourth pedigerous somites. Genitoabdomen dorsally unsegmented and ventrally 4-segmented; anal somite with distinct anal prominence. Caudal ramus ( Fig. 152D ) fusiform, unarmed, distinctly articulated from anal somite, about 2.07 times longer than wide (58×28 μm), widest in middle. Egg sac ( Fig. 152E ) containing 5 or 6 eggs; each egg 138 μm in diameter.

Rostrum absent. Antennule ( Fig. 152F ) unsegmented, about 1.6 times longer than wide (48×30 μm), with straight anterior margin and strongly protruded posterior margin; armed with 4 small setae on apex (grouped as 2 and 2). Antenna ( Fig. 152G ) incompletely 2-segmented, about 100 μm long, 52 μm wide; proximal segment un- armed; distal segment as long as proximal segment, ornamented with spinules on concave surface; armed with 6 setae, lengths of setae I-VI (medial to lateral) 14, 15, 11, 15, 20, and 31 μm, respectively; all setae curved medially; 3 medial setae (setae I-III) widely separated from other setae.

Labrum ( Fig. 152H ) with 3 small patches of spinules on each side of ventral surface; palp gradually inflating distally. Mandible tapering, less than half as wide as labral palp. Maxillule consisting of precoxa ( Fig. 152J ) and palp ( Fig. 152I ); distal sclerotized region of precoxa with 2 small tubercles (subdistal and proximal) and spinulecovered distal margin; endite of precoxa tipped with 1 spinulose spine and more than 20 setules; palp with 5 spines on distal margin and 1 naked seta on lateral margin. Maxilla ( Fig. 152K ) bearing spinulose process on endite of proximal segment; distal segment with 1 spinulose, spiniform process on subdistal anterior surface, 1 transverse row of minute spinules in middle of anterior surface, and 1 small seta proximally on posterior surface. Maxilliped absent.

Legs 1-4 each consisting of 2-segmented protopod and unsegmented rami ( Fig. 152L, M ); protopods unarmed. Exopods bearing patch of minute spinules proximally on lateral margin; exopods of legs 1, 2, and 4 tipped with small cusp; exopods of legs 1 and 2 with minute cusp subdistally on lateral margin ( Fig. 152L ). Endopods 43×20, 45×20, 40×21, and 33×20 μm, respectively, in legs 1-4. Lengths of laterodistal and mediodistal setae 38 and 32, 42 and 34, 42 and 31, and 46 and 36 μm, respectively, in legs 1-4.

Leg 5 ( Fig. 152N ) unarmed, wider than long (109×190 μm).

Male. Unknown.

Remarks. The antennule of bK neçcaledçnẚcus sp. nov. is armed with 4 setae. Similar numbers of setae (3-5 setae) on the antennule are observable in more than 15 known species of bnterçcçla ( Table 6 ). Seven of these species are similar to b. neçcaledçnẚcus sp. nov., because they share the same unsegmented, bulbous shaped antennule, which is circular or semicircular (D-shaped). These seven species are b. parapterçphçrus, b. mabulensẚs sp. nov., b. dẚcaudatus, b. mammẚferus, b. rçbustus sp. nov., b. parvus sp. nov., and b. angustus sp. nov. The first two of these, b. parapterçphçrus and b. mabulensẚs sp. nov., can be excluded from further comparison because both have 5 setae on the antenna, whereas b. neçcaledçnẚcus sp. nov. has 6 setae.

The remaining five species can be distinguished from b. neçcaledçnẚcus sp. nov. as follows: bK dẚcaudatus has, unlike b. neçcaledçnẚcus sp. nov., an elongate antenna and a posterodorsal process on the cephalic shield; bK mammẚferus has caudal rami which are wider than long (in contrast to about twice as long as wide in b. neçcaledçnẚcus sp. nov.). In bK rçbustus sp. nov. there are 3 setae on the antennule, the narrow caudal rami are 3.0 times longer than wide, and the endopods of swimming legs are 2-segmented, although the segmentation is incomplete. bnterçcçla parvus sp. nov. differs in having 3 setae on the antennule, a dorsal tubercle on the first and second pedigerous somites, and a spinulose tubercle on the medial margin of the proximal maxillary segment. Finally, bK angustus sp. nov. has 5 setae on the antennule, tapering caudal rami, and a bifurcate process on the endite of the proximal maxillary segment.

The third pedigerous somite of b. neçcaledçnẚcus sp. nov. bears a small dorsal tubercle, although it is easy to overlook because of its small size. The presence of a dorsal tubercle or process on the cephalic shield or on any pedigerous somites is known for b. dẚcaudatus (on the cephalic shield), b. quadrẚsetus sp. nov. (on the second and third pedigerous somites), b. parvus sp. nov. (on the first and second pedigerous somites), and b. tuberculatus sp. nov. (on the first pedigerous somite). The presence of a tubercle on the third pedigerous somite only is unique within the genus.

Figures

FIG. 152. bnterçcçla neçcaledçnẚcus sp. nov., female. A, habitus, dorsal; B, habitus, right; C, genitoabdomen, left; D, caudal ramus; E, egg sac; F, antennule; G, antenna; H, labrum; I, palp of maxillule; J, precoxa of maxillule; K, maxilla; L, leg 1; M, leg 3; N, leg 5. Scale bars: A, B, E, 0.1 mm; C, N, 0.05 mm; D, G, K-M, 0.02 mm; F, H-J, 0.01 mm.