Lernanthropodes trachinoti Pillai, 1962

Boxshall, Geoff A., Bernot, James P., Barton, Diane P., Diggles, Ben K., Q-Y, Russell, Atkinson-Coyle, Toby & Hutson, Kate S., 2020, Parasitic copepods of the family Lernanthropidae Kabata, 1979 (Copepoda: Siphonostomatoida) from Australian fishes, with descriptions of seven new species, Zootaxa 4736 (1), pp. 1-103 : 14

Lernanthropodes trachinoti Pillai, 1962

Material examined: none.

Differential diagnosis: Cephalothorax longer than wide; lateral margins near linear and tapering anteriorly towards narrow frontal margin; posterior margin concave. Trunk comprising elongate anterior part (second and third pedigerous somites) with more or less parallel sides, lacking dorsal trunk plate, so fourth pedigerous somite and urosome exposed in dorsal view. Urosome comprising fifth pedigerous somite, genital complex and abdomen, all fused; entire urosome sometimes flexed vertically upwards. Egg sacs linear. Caudal rami elongate, about 2.2 times longer than maximum width. Leg 3 lamellate; lamellae fused to form large ventral-ventrolateral tubular extension directed posteriorly but open dorsomedially so urosome visible dorsally: rear margin of tubular extension trilobate. Leg 4 biramous, rami forming slender flattened lobes, almost equal in length. Leg 5 absent. Body length of adult ♀ 4.5 mm (from Pillai, 1962), mean body length of adult ♂ 1.15 mm (from Kabata, 1979a).

Distribution: The original description of L. trachinoti was based on material collected from the carangid Trachinotus blochii (Lacepède, 1801) caught off Kerala, India ( Pillai, 1962). Kabata (1979a) recorded the adult male and an immature female of L. trachinoti from Trachinotus botla (Shaw, 1803) caught at Tangalooma in Moreton Bay. It has since been reported from T. blochii caught off Taiwan ( Ho et al., 2011).

Remarks: The female of L. trachinoti was redescribed in detail by Ho et al. (2011). They noted the close resemblance between their material and the original description of Pillai (1962) but remarked that the females described by Pillai (1985) in his monograph differ and may represent a different species. Kabata (1979a) provided the only available description of the male, based on Australian material.

The genus Lernanthropodes is well defined by its lack of a dorsal trunk plate on the fourth pedigerous somite and by configuration of the third legs which are fused to form a large ventral-ventrolateral tubular extension enclosing the posterior end of the body except for a dorsomedial opening through which the urosome is visible in dorsal view ( Ho & Do, 1985). These diagnostic characters are shared with the monotypic genus Chauvanium , recently established by Kazachenko et al. (2017) to accommodate C. chauvani Kazachenko, Kovaleva, Nguyen & Ngo, 2017 described from the carangid Alepes melanoptera (Swainson, 1839) caught in Bakbo Gulf, Vietnam. The morphological basis for the new genus is the position of the posterior trunk “which is bent dorsally and directed towards the anterior end of the body” in Chauvanium , whereas “it is not bent dorsally and is directed towards the posterior end of the body” in Lernanthropodes ( Kazachenko et al., 2017) . Unfortunately, this character does not appear to be robust as a generic discriminant. Indeed, Pillai (1985: Fig. 209A–B) illustrated a female L. trachinoti with its entire urosome flexed vertically upwards and out through the dorsomedian opening, whereas the female of the same species illustrated by Ho et al. (2011) had its urosome directed posteriorly. The ability to flex the urosome upwards is exhibited by species of Lernanthropodes and there is no other support for Chauvanium is a distinct genus. The type species of Chauvanium is here transferred to Lernanthropodes as L. chauvani ( Kazachenko, Kovaleva, Nguyen & Ngo, 2017) , new combination, and Chauvanium is here recognized as a junior subjective synonym of Lernanthropodes .