Enterocola hessei Chatton & Harant, 1924

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 : 195-197

Enterocola hessei Chatton & Harant, 1924

( Figs. 123 , 124 )

Material examined. 3 ♀♀ (MNHN-IU-2014-21539, 1 ♀ dissected) from Clavelẚna lepadẚfçrmẚs (Müller, 1776), Saint-Vaast-la-Hougue, Atlantic coast of France, Monniot coll. ; 4 ♀♀ (MNHN-IU-2014-21540) from CK lepadẚfçrm ẚs, Roscoff, France .

Supplementary description of female. Body eruciform, straight, consisting of cephalosome, 5-segmented trunk, and incompletely 3-segmented genitoabdomen. Body length 2.21 mm; maximum width 664 μm (across sec- ond pedigerous somite). Cephalosome wider than long. First to fourth pedigerous somites each bearing distinct dorsal tergite; tergites simple, not forming dorsolateral folds; pedigerous somites each bearing pair of large, subglobular interpodal protrusions on ventral surface between left and right legs ( Fig. 123B , 124A, B ). Fifth pedigerous somite not articulated from fourth pedigerous somite. Anal somite bearing distinct anal prominence dorsally. Caudal rami ( Fig. 123C ) slightly divergent, well separated from each other, and clearly articulated from anal somite; each ramus sub-rectangular, unarmed, 2.27 times longer than wide (159×70 μm), gradually narrowing distally, with longer outer and shorter inner margins. Egg sac ( Fig. 123D ) L- or C-shaped, 2.0× 0.35 mm in measured sample, containing numerous eggs; each egg about 130 μm in diameter.

Rostrum absent. Antennule ( Fig. 123E ) about 135×83 μm, incompletely 2-segmented, gradually narrowing dis- tally; longer proximal segment with 1 small seta distally; distal segment armed with 12 unequal setae and 1 minute spinule, several of distal setae setule-like; longest seta 30 μm long. Antenna ( Fig. 123F ) about 245×100 μm, indis- tinctly 2-segmented; shorter proximal segment unarmed and unornamented; longer distal segment with rounded distal margin, ornamented with numerous minute spinules on convex anterior surface, and armed with 6 naked setae of lengths 31, 55, 50, 50, 94, and 107 μm, from medial to lateral (setae I-VI), respectively; shortest medial seta po- sitioned at 80% along medial margin of segment.

Labrum ( Fig. 123G ) subcircular, smooth, with pair of slender, spinulose palps. Mandible ( Fig. 123G ) setiform, spinulose, similar to labral palp. Maxillule consisting of precoxa and palp; precoxa ( Fig. 123H ) with 1 subdistal and 2 distal projections on distal sclerotized part and endite bearing 1 spinulose seta and about 10 thin setules; palmshaped palp ( Fig. 123I ) with 6 spinulose setae, 5 on distal and 1 on lateral margins, latter seta longer than distal setae. Maxilla ( Fig. 123J ) 2-segmented; proximal segment with 1 large smooth tubercle proximally on medial side and mediodistal endite bearing spinulose process; second segment unequally bifurcate distally, armed with 1 small spine proximally on posterior surface. Maxilliped absent.

Legs 1-4 each consisting of 2-segmented protopod and 1-segmented rami; protopods unarmed. Exopods shorter than endopods: exopods of legs 1, 2, and 3 with rudimentary articulation distally; exopod of leg 3 claw-like ( Fig. 124B ). Endopods each bearing 2 setae on distal margin, lateral seta longer than medial seta in legs 1-4. Endopodal segment 93×41, 102×48, 102×52, and 91×57 μm, respectively, in legs 1-4. Distal setae of leg 1 ( Fig. 124A ) endopod 159 (lateral) and 136 μm (medial), therefore, lateral seta about 1.7 times longer than endopodal segment and 1.17 times longer than medial seta. Distal setae of leg 3 endopod 184 (lateral) and 161 μm (medial). Proportional lengths of distal setae of endopods of legs 2 and 4 similar to those of leg 3.

Leg 5 ( Fig. 123K ) lamellate, smooth, wider than long (267×370 μm); armed with 2 minute setae, separated by distance of about 230 μm.

Male. Unknown.

Remarks. In her redescription of this species, Ooishi (2010a) mentioned or illustrated that (1) the ventral surface of the metasome bears 4 prominent pairs of interpodal protrusions, (2) the antennule is armed with 12 setae, (3) leg 1 endopod is 2.3 times longer than wide, and (4) the laterodistal seta of leg 1 endopod is 1.2 times longer than the mediodistal seta. These features are almost exactly the same as in our specimens. Some discrepancies, such as the slightly longer caudal rami (2.6 times longer than wide) are minor, while others such as the 5-segmented genitoabdomen in Ooishi’s specimens, may be due to the reproductive state of the material. Both Ooishi’s and our samples of this copepod species were collected from the ascidian Clavelẚna lepadẚfçrmẚs in the vicinity of the type locality.

Figures

FIG. 123. bnterçcçla hesseẚ Chatton & Harant, 1924, female. A, habitus, dorsal; B, habitus, ventral; C, caudal rami, ventral; D, egg sac; E, antennule; F, antenna; G, labrum and mandibles; H, precoxa of maxillule; I, palp of maxillule; J, maxilla; K, leg 5. Scale bars: A, B, 0.2 mm; C, K, 0.1 mm; D, 0.5 mm; E, 0.02 mm; F-J, 0.05 mm.

FIG. 124. bnterçcçla hesseẚ Chatton & Harant, 1924, female.A, leg 1; B, leg 3. Scale bars: 0.1 mm.