Hatschekia niger, 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 : 402-406

publication ID	https://doi.org/ 10.5252/z2013n3a3
persistent identifier	https://treatment.plazi.org/id/51692336-BA5C-FFD8-E066-693A46ECA689
treatment provided by	Felipe
scientific name	Hatschekia niger
status	sp. nov.

Treatment

Hatschekia niger n. sp.

Hatschekia sp. 18 – Justine et al. 2012: fig. 2B.

TYPE HOST. — Macolor niger (Forsskål, 1775) ( Perciformes : Lutjanidae ).

TYPE LOCALITY. — New Caledonia.

ETYMOLOGY. — The specific name of the new species, niger , is treated as a noun in apposition and is based on its host.

MATERIAL EXAMINED. — Holotype female (MNHN- IU-2013-4019) dissected on 10 slides. Paratype female ( NHMUK 2012.1320) dissected on 10 slides. 39 ♀♀ undissected paratypes: from Macolor niger [JNC 1716B], Passe de Dumbéa, New Caledonia, coll. J.-L. Justine, 16.I.2006. 10 ♀♀ undissected in MNHN Cp. 0000, 17♀♀ undissected in NHMUK 2012.1321-1330, 12 ♀♀ undissected in MABIK CR00179959-CR00179968.

ADDITIONAL MATERIAL. — 1 ♀ from M. niger [JNC1717] ; Passe de Dumbéa , New Caledonia, coll. J.-L. Justine, 16.I.2006. ( NHMUK 2012.1331 About NHMUK ) .

DESCRIPTION

Female

Total body length 1190-1500 Μm (n = 10, mean = 1330 Μm) excluding caudal rami. Body ( Fig. 15A View FIG ) elongate. Cephalothorax ( Fig. 15A View FIG ) wider than long (218 × 259 Μm), convex angular lateral margins and straight posterior margin; dorsal surface with distinct chitinous markings in form of “m-shape”, bar in mid-line extending beyond posterior tips of curved, undivided lateral bars, with short side branches at about 60% of length, and divided at posterior end. Trunk ( Fig. 15A View FIG ) cylindrical, longer than wide (1230 × 286 Μm), with nattower neck region anteriorly; lateral margins straight to slightly convex; widest about in middle; posterior margin with three or four nodules on either side, situated dorsal to urosome ( Fig. 16E View FIG ), and with paired minute bifid processes located ventrally at posterolateral corners of trunk ( Fig. 16F View FIG ). Urosome ( Fig. 16E, F View FIG ) excluding caudal ramus shorter than wide (58 × 102 Μm), comprising fused genital complex and abdomen. Caudal ramus ( Fig. 16E, F View FIG ) widest distal to mid-level, longer than wide (28 × 16 Μm), with six naked setae. Egg sac containing ten eggs (single specimen with egg sacs).

Rostrum absent. Antennule ( Fig. 15B View FIG ) 5-segmented; length 207 Μm; armature formula: 9, 4, 4, 1, 11 + ae. Antenna ( Fig. 15C View FIG ) 3-segmented; proximal segment unarmed; middle segment (basis) swollen, slightly tapering, ornamented with surface pits; terminal claw small without ornamentation, subdivided by incomplete suture; total length 223 Μm; middle segment length 178 Μm; terminal claw length 45 Μm. Parabasal papilla not observed. Oral cone robust. Mandible ( Fig. 15D View FIG ) styliform, apparently unarmed. Maxillule ( Fig. 15E View FIG ) bilobate; both lobes armed with two stout processes. Maxilla ( Fig.15F View FIG ) 4-segmented; proximal segment unarmed; second segment swollen with one proximal seta on medial margin; third segment rod-like, elongate, with one distal seta; terminal segment small, with one small seta and bifid claw. Maxilliped absent.

Leg 1 ( Fig. 16A View FIG ) biramous; protopod bearing one inner and one fine outer seta; exopod indistinctly 2-segmented, exp-1 with one outer seta, exp-2 with four setae ornamented with fine hairs; endopod 2-segmented, enp-1 unarmed, enp-2 with two distal and three inner setae ornamented with fine hairs; protopod length 85 Μm; exopod length 63 Μm; endopod length 51 Μm. Leg 2 ( Fig. 16B View FIG ) biramous; protopod elongate, laterally-directed, lacking outer seta; exopod indistinctly 2-segmented, exp-1 with one outer seta, exp-2 with three distal setae ornamented with fine hairs and two naked inner setae; endopod 2-segmented, enp-1 slender, with inner seta; enp-2 with one inner and three distal setae ornamented with fine hairs; protopod length 120 Μm; exopod length 120 Μm; endopod length 102 Μm. Protopod and rami of legs 1 and 2 ( Fig. 16A, B View FIG ) ornamented with crescentic rows of blunt spinules on surface. Intercoxal sclerites of both legs elongate, unornamented and unmodified. Leg 3 ( Fig. 16C View FIG ) represented by small laterallylocated lobe with two naked setae just anterior to mid-length of trunk. Leg 4 ( Fig. 16D View FIG ) represented by small lobe with one naked seta located at three quarters length of trunk.

Male

Unknown.

REMARKS

Hatschekia niger n. sp. shares the possession of nodules on the posterior margin of the trunk with H. nodosa Ho & Kim, 2001 . These nodules may be derived from modified posterior trunk processes but their position dorsal to the urosome might indicate that they are novel structures. Both species occur on the gills of lutjanid hosts and share other characters such as the pattern of chitinous markings on the dorsal surface of the cephalothorax. They are undoubtedly closely related but there are several differences between the new species and H. nodosa . In the new species the setal formula of the antennule is 9, 4, 4, 1, 11 + ae, whereas in H. nodosa it is 9, 5, 4, 3 + ae, 11, according to Ho & Kim (2001). The apparent difference in antennulary segmentation needs confirmation: the configuration of the two distal segments shown by Ho & Kim (2001) is probably erroneous since the aesthetasc is shown as carried on the subapical segment in their drawings but it is always found on the apical segment in Hatschekia . The antenna of H. nodosa carries an inner seta on the coxobasis of the antenna which, as Ho & Kim (2001) pointed out, is an unusual feature for the genus. No such seta was present in the new species. The mandible of H. nodosa has six small teeth whereas in H. niger n. sp. the mandible tapers to a curved pointed tip without additional teeth. The exopod of leg 1 is armed with five setae in H. nodosa but only four in the new species and the setae on the exopod of leg 2 differ in relative lengths: in the new species there are two apical setae of similar length compared to a short outer seta and long inner seta on the apex in H. nodosa . No variation was detected in the number of setae present on the exopod of leg 1 in the new species.The curved lateral bars on the cephalothorax of H. nodosa have anterolateral side branches ( Ho & Kim, 2001: Fig. 2B View FIG ) which are absent in H. niger n. sp. Finally these two species also differ slightly in the shape of the urosome, which is relatively wider compared to its length in the new species. Taken together, we consider that these morphological differences are sufficient to justify the recognition of the new species, although we know little about variability in this genus and it would be advisable to test the separation of these two species using molecular data.