Hatschekia etelisicola, Lee & Lee & Boxshall, 2013

Lee, Soyoung, Lee, Wonchoel & Boxshall, Geoffrey, 2013, Seven new species of Hatschekia Poche, 1902 (Copepoda: Siphonostomatoida: Hatschekiidae) parasitic on fishes of New Caledonia, and a redescription of H. cadenati Nunes-Ruivo, 1954, Zoosystema 35 (3), pp. 377-413 : 394-398

Hatschekia etelisicola n. sp.

Hatschekia sp. 21 – Justine et al. 2012: fig. 2A

TYPE HOST. — Etelis carbunculus (Cuvier, 1828) ( Perciformes : Lutjanidae ).

ADDITIONAL HOST. — Etelis coruscans Valenciennes, 1862 ( Perciformes : Lutjanidae ).

TYPE LOCALITY. — Deep water, off Passe de Dumbéa, New Caledonia (22°25’S, 166°10’E).

ETYMOLOGY. — The specific name of the new species, etelisicola , is based on the generic name of the host combined with - icola, meaning inhabitant.

MATERIAL EXAMINED. — Holotype female (MNHN- IU-2013-4013) dissected on 12 slides. Paratype female ( NHMUK 2012.1302) dissected on 3 slides. 5♀♀ undissected paratypes (1 ♀ for SEM) from Etelis carbunculus [JNC2459]: deep water, off Passe de Dumbéa, New Caledonia (22°25’S, 166°10’E), coll.J.-L. Justine, 26. VI.2008. 4 ♀♀ undissected in MABIK CR00179945-CR00179948.

ADDITIONAL MATERIAL. — 3 ♀♀ from Etelis coruscans [JNC113D] ; CHONDRICAL PAL10 , New Caledonia

(23°01’06”S, 166°55’83”E), depth 467-489 m, coll. J.- L. Justine, 1.II.2002. ( NHMUK 2012. 1303-1305); 10 ♀♀ from E. coruscans [JNC114D]; CHONDRICAL PAL10, New Caledonia (23°01’06”S, 166°55’83”E), depth 467-489 m, coll. J.-L. Justine, 1.II.2002. ( NHMUK 2012 . 1306-1315) ;

1 ♀ from E. coruscans [JNC116D]; CHONDRICAL PAL10 , New Caledonia (23°01’06”S, 166°55’83”E), depth 467-489 m, coll. J.-L. Justine, 1.II.2002. (MNHN- IU-2013-4014) ;

5 ♀♀ from E. coruscans [JNC117D]; CHONDRICAL PAL10 , New Caledonia (23°01’06”S, 166°55’83”E), depth 467-489 m, coll. J.-L. Justine, 1.II.2002. ( MABIK CR00179949 - CR00179953 ) ;

16 ♀♀ from E. coruscans [JNC2616]; off Barrier reef near Passe de Dumbéa, New Caledonia (22°19.67’S, 166°12.899’E), coll. J.-L. Justine, 3.VII.2008. (MNHN- IU-2013-4015) .

DESCRIPTION

Female

Total body length 3000-3520 Μm (n = 10, mean = 3120 Μm) excluding caudal rami. Cephalothorax ( Fig. 11A ) subtriangular (322 × 427 Μm), widest near slightly curved posterior margin; dorsal surface with distinct 3-branched chitinous markings, bar in mid-line simple, extending beyond posterior tips of lateral bars; lateral bars following margin of cephalothorax with irregular posterior edge bearing traces of side branches.Trunk ( Fig. 11A ) cylindrical, much longer than wide (2798 × 484 Μm); anterior half consistently broader than posterior half; posterior part bearing legs 3 and 4, narrower than anterior, but with slight constrictions in some specimens; lacking posterior processes. Urosome ( Fig. 12E ) excluding caudal ramus small, shorter than wide (49 × 109 Μm) comprising fused genital complex and abdomen ( Fig. 12E ). Caudal ramus ( Fig. 12E ) longer than wide (35 × 21 Μm), with six naked setae clustered near apex. Egg sacs with mean of 31.5 eggs per sac, range from 27 to 36 eggs per sac. Rostrum absent.Antennule ( Fig.11B ) 4-segmented; length 179 Μm; armature formula: 10, 10, 1, 11 + ae. Antenna ( Fig. 11C ) 3-segmented; proximal segment unarmed (not figured); middle segment (basis) elongate, slightly tapering distally, ornamented with surface pits; terminal claw small, subdivided by incomplete suture; without ornamentation; total length 213 Μm; middle segment length 163 Μm; terminal claw length 50 Μm. Parabasal papilla not observed. Oral cone robust. Mandible ( Fig.11D ) slender, rodlike, with five small blunt teeth. Maxillule ( Fig.11E ) bilobate; both lobes armed with two stout tapering processes. Maxilla ( Fig.11F ) 4-segmented; proximal segment unarmed; second segment elongate, with one basal seta; third segment rod-like, elongate, with one distal seta; terminal segment small, with one small seta and bifid claw. Maxilliped absent.

Leg 1 ( Fig. 12A ) biramous; protopod bearing one fine inner spine and one outer seta; exopod indistinctly 2-segmented, exp-1 with one outer seta, exp-2 with three inner and three distal setae; endopod 1-segmented, with three inner setae, two distal setae, and one outer seta; protopod length 61 Μm; exopod length 45 Μm; endopod length 31 Μm. Leg 2 ( Fig. 12B ) biramous; exopod indistinctly 2-segmented, exp-1 with one outer seta, exp-2 with five setae; endopod indistinctly 2-segmented, enp-1 with one inner seta, enp-2 with one inner seta, three terminal setae, and one outer seta; outer protopodal seta missing in figured specimen, present in other specimens; protopod length 84 Μm; exopod length 53 Μm; endopod length 40 Μm. Protopod and rami of legs 1 and 2 ( Fig. 12A, B ) ornamented with crescentic rows of blunt spinules on surface. Intercoxal sclerites of both legs elongate, unornamented and unmodified. Legs 3 and 4 ( Fig. 12C, D ) each represented by small laterally located lobe tipped with one simple plumose seta and positioned at two thirds and 7/8 of length of trunk.

Male

Unknown.

REMARKS

Hatschekia etelisicola n.sp. is distinctive in having a very long trunk and, judging from the posterior location of vestigial legs3 and 4, this length comes particularly from elongation of the first two pedigerous somites in the trunk. The trunk is about 5.8 times longer than wide and it narrows distinctly in the posterior half. The division into broader anterior and narrow posterior parts is a consistent feature, irrespective of the state of fixation and preservation of the specimen. Relatively few other species have a trunk more than 5 times longer than wide.These are H. tenuis (Heller, 1865) , H. sargi (Brian, 1902) , H. linearis Wilson, 1913 , H. pagrosomi Yamaguti, 1939 , H. gracilis Yamaguti, 1954 , H. longibrachium Yamaguti, 1954 , H. atagonel Jones, 1985 , H. manea Jones & Cabral, 1990 , H. clava Kabata, 1991, H. squamigera Kabata, 1991 , and H. tanysoma Ho & Kim, 2001 . None of these has a trunk showing marked division into broader anterior and narrow posterior parts.

The new species differs from both H. clava and H. tanysoma in the position of leg 3 – which is located just anterior to the mid-length of the trunk in both species, but well within the posterior third of the trunk in the new species. Hatschekia tanysoma and H. clava also possess minute posterolateral processes on the trunk which H. etelisicola n. sp. does not. Hatschekia squamigera has an elongate cephalothorax (1.35 times longer than wide) and has distinct posterolateral processes on the trunk. In contrast the cephalothorax of H. etelisicola n. sp. is wider than long and it lacks processes on the trunk. The new species differs from H. atagonel which has a well defined transverse welt in its neck region and has a cephalothorax that is widest anteriorly. Hatschekia manea has a 3-segmented antennule compared to 4-segmented in H. etelisicola n. sp. and this species has fewer setal elements on both rami of both legs 1 and 2 than the new species.

Hatschekia tenuis has a very elongate trunk, over 8 times longer than wide, which is widest in its posterior half. This is different in form from the new species but trunk shape can vary with reproductive state. According to Jones (1985), H. tenuis also has a distinctive conical projection at the base of the hook on the antenna, which is lacking in the new species. Hatschekia pagrosomi is also an extremely elongate form but differs in having markedly fewer setation elements on the exopods of legs 1 and 2 than in H. etelisicola n. sp.

Hatschekia sargi has a linear trunk and has smoothly convex lateral margins to the cephalothorax. In contrast the trunk of the new species is narrower posteriorly and the cephalothorax is distinctly triangular in shape from dorsal view, with its lateral margins tapering anteriorly from its widest point near its rear margin.

The trunk of H. longibrachium is much wider posteriorly than anteriorly and also differs from the new species in having a cephalothorax which is widest in the middle compared to widest posteriorly as in the new species. Hatschekia linearis has a distinctive shape as it has swellings marking the origins of legs 1 and 2, and also differs from H. etelisicola n. sp. in having a 3-segmented antennule (cf. 4-segmented) and in having many fewer setal elements on both rami of legs 1 and 2. Hatschekia gracilis is another elongate species with a trunk that is much wider posteriorly than anteriorly.It has a distinctive pattern of chitinous markings on the dorsal surface of the cephalothorax with an additional pair of branched bars located between the usual lateral bars and the mid-line bar. The new species has relatively reduced chitinous markings and no additional branched bars are present.

The significant differences between H. etelisicola n. sp. and all these other species that share an elongate trunk justify the establishment of the new species.

Figures

FIG. 11. — Hatschekia etelisicola n. sp. female: A, habitus, dorsal; B, antennule; C, antenna; D, mandible; E, maxillule; F, maxilla. Scale bars: A, 250 μm; B, C, F, 50 μm; D, E, 25 μm.

FIG. 12. — Hatschekia etelisicola n. sp. female: A, leg 1; B, leg 2; C, leg 3; D, leg 4; E, posterior part of trunk, ventral. Scale bars: A-D, 25 μm; E, 50 μm.