Gunenotophorus globularis Buchholz, 1869

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 : 145-148

Gunenotophorus globularis Buchholz, 1869

( Figs. 95 , 96 )

Material examined. 14 ♀♀ (MNHN-IU-2018-1819) and 2 dissected ♀♀ from Polycarpa pomaria (Savigny, 1816) , Kristineberg; 1 ♀ (MNHN-IU-2018-1820) from P. pomaria, Noirmoutier , France; 1 ♀ (MNHN-IU-2018- 1821) and 1 dissected ♀ from P. kornogi Glémarec & Monniot C., 1966 , Norwegian Sea Norbi CP 11; 3 ♀♀ (MNHN-IU-2018-1822) and 1 dissected ♀ from P. mamillaris (Pallas, 1774) , Bioice Stn 2307; 1 juvenile (MNHN-IU-2009-2467) and 2 dissected juveniles from Styela canopus (Savigny, 1816) , Port Gare Maritime, Vannes, France, L. Roux coll., 23 April 2009.

Supplementary description of female. Body ( Fig. 95A ) comprising cephalosome, swollen metasome, and indistinctly segmented urosome. Body length 5.44 mm in dissected specimen. Metasome modified as unsegmented, spherical brood pouch, formed by fusion of first to fourth pedigerous somites: first pedigerous somite defined from posterior part of metasome by weak suture line in some specimens. Fifth pedigerous somite short, not defined from metasome. Freeurosome ( Fig. 95B ) 3-segmented, consistingof genital double-somite, and 2-segmented abdomen. Genital double-somite with incomplete dorsal and ventral suture lines marked by wrinkled integument, near anterior third. Anal somite with wrinkled dorsal suture line near midlength in some specimens. Distal part of anal somite flexible and eversible, ornamented with numerous spinules on dorsal and ventral surfaces. Caudal ramus ( Fig. 95C ) twice as long as wide, indistinctly defined from anal somite; rami directed posteriorly, but directed more laterally when anal somite expanded; rami armed with 3 or 4 small spines distally and 2 small setae near distal third.

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-I	I-1; I-1; III, 4	0-1; 0-1; 1, 2, 3
Leg 2	0-0	1-0	1-0; 1-0; 3, 1, 1	0-1; 1, 3, 1
Leg 3	0-0	1-0	1-0; 1-0; 3, 1, 1	0-0; 0, 2, 1
Leg 4	0-0	0-0	I-1; I-0; 2, 1, 1	0-0; 0, 2, 0

Rostrum ( Fig. 95D ) linguiform, longerthanwide, tapering, covered by numerous minute setules; lateral margins slightly concave ( Fig. 95D ) or convex.Antennule ( Fig. 95E ) stronglytapering; obscurely segmented, with 4 incomplete suture lines and several surface wrinkles; armed with thin setae and ornamented with minute setules on anterior surface; setae hardly distinguishable from setules.Antenna ( Fig. 95F ) stout, 4-segmented; coxa short and unarmed; basis only slightly longer than wide; first endopodal segment as long as basis, unarmed; compound distal endopodal segment about 1.8 times longerthan wide (79×44 μm), armed with 5 small setae plusterminal claw, about half as long as segment.

Labrum ( Fig. 95G ) stronglytapering, withrounded distal margin and large semicircular lobe on each side. Mandible ( Fig. 95H ) with 5 teethand 1 or 2 small proximal setae on coxal gnathobase; basis with 1 seta on distal medial margin; exopod with 5 setae, second outer seta largest, outermost seta small, less than half length of second outer seta; endopod with 1 and 5 setae on first and second segments, respectively, outermost seta on second segment small, less than one-third length of adjacent seta. Maxillule ( Fig. 95J ) with 9 setae on arthrite, 1 on coxal endite and 2 on epipodite; exopod incompletely defined at basewith 4 large setae distally; baseoendopodwith 4 setae. Maxilla ( Fig. 96A ) 3-segmented; syncoxa (first segment) with 3, 2, and 3 setae on first to third endites; basis with robust claw plus 2 setae; endopod small, unsegmented with 3 (occasionally 4 or 5) smallsetae. Maxilliped ( Fig. 96B ) unsegmented and armed with 6 (occasionally 5) setae on medial margin and 1 broad seta apically.

Leg 1 ( Fig. 96C ) with 3-segmented rami. Legs 2–4 ( Fig. 96 D–H) each with 3-segmented exopod and 2- segmented endopod. Inner coxal seta lacking in legs 1–4. Outer seta on basis digitiform proximally and thin distally in leg 1, very small in legs 2 and 3, and absent inleg 4. Innerdistalspineonbasisofleg 1 setiform, pinnate along proximal half and spinulose distally. Exopod of leg 1 broadened, slightly longer than endopod. Endopods of legs 2–4 much smaller, less than half as long as exopods, with shorter proximal segment and much longer distal segment. Distal endopodal segment of legs 2 and 3 ornamented with 3 rings of minute setules in distal region. Setae on leg 1 large and pinnate, setae on legs 2–4 rudimentary. Distal endopodal segment of leg 3 with trace of articulation near middle. Setation of legs 2–4 variable. Armature formula for legs 1–4 of dissected specimen as follows:

Leg 5 rudimentary, represented by small, slightly curved lobe tipped with 1 small seta.

Male. Not found in this study.

Remarks. The juvenile specimens, probable copepodid V, were found to have 3-segmented endopods inlegs 2–4, so the 2-segmented adult condition probably results from secondary fusion during the final moult to adult. The second endopodal segment of the mandible possessed only 4 setae and lacked the small outer seta of the adult. This species has been reported from over 20 species of ascidian hosts ( Illg, 1958; Gotto, 1993) and both Polycarpa kornogi and Styela partita , reported here, are new host records. This species has a wide geographical distribution with records extending from the Atlantic coast of North America across to Europe and the Mediterranean, south to South Africa and into the Indian Ocean ( Gotto, 1993).

Figures

FIGURE 95. Gunenotophorus globularis Buchholz, 1869, female. A, habitus, right; B, urosome, ventral; C, left caudal ramus, dorsal; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, paragnath; J, maxillule. Scale bars: A, 1 mm; B, 0.2 mm; C, D, 0.1 mm; E–J, 0.05 mm.

FIGURE 96. Gunenotophorus globularis Buchholz, 1869, female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, endopod of leg 2; F, leg 3; G, endopod of leg 3; H, leg 4. Scale bars: A–C, E, G, 0.05 mm; D, F, H, 0.1 mm.