Lernanthropus atrox Heller, 1865

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 : 26-27

Lernanthropus atrox Heller, 1865

Material examined: 19♀♀, 10♂♂ from Rhabdosargus sarba (Forsskål, 1775) , Coffs Harbour , New South Wales, 26 November 1981; collected by K. Rohde. 2♀♀, 1♂ from R. sarba, Coffs Harbour , New South Wales, 1980; collected by K. Rohde. 21♀♀, 13♂♂ from R. sarba, Coffs Harbour , New South Wales, October 1980; collected by K. Rohde. 6♀♀, 12♂♂ from R. sarba, Coffs Harbour , New South Wales, 1980; collected by K. Rohde. 12♀♀, 7♂♂ from R. sarba, Coffs Harbour , New South Wales, 19 April 1982; collected by K. Rohde ; NHMUK Reg. No. 1984.106–111 . 5♀ from R. sarba ( TC17083 ), Moreton Bay , Queensland, 13 January 2016; collected by G.A. Boxshall ; QM Reg. No. W29480 . 2♀♀ from R. sarba ( TC17094 ), Moreton Bay , Queensland, 13 January 2016; collected by G.A. Boxshall.

2♀♀ from Acanthopagrus australis (Günther, 1859) ( TC17133 ), Moreton Bay , Queensland, 14 January 2016; collected by G.A. Boxshall; QM Reg, No. W29481 . 2♀♀, 1♂ from A. australis ( TC17316 ), Moreton Bay , Queensland, 20 January 2016; collected by G.A. Boxshall; NHMUK Reg. No. 2018.244–246 . 1♀ from A. australis ( TC17135 ), Moreton Bay , Queensland, 14 January 2016; collected by G.A. Boxshall.

3♀♀ from Chrysophrys auratus (Forster, 1801) ( TC17145 ), Moreton Bay , Queensland, 14 January 2016; collected by G.A.Boxshall ; NHMUK Reg. No. 2018.247–249 . 1♀ from C. auratus ( TC 16941 ), Moreton Bay , Queensland, 08 December 2015; collected by S.C. Cutmore ; NHMUK Reg. No. 2018.250 . 2♂♂ from C. auratus ( TC17575 ), Moreton Bay , Queensland, 25 June 2016; collected by G.A. Boxshall. 13♀♀, 9♂♂ from C. auratus, Coffs Harbour , New South Wales, collected by K. Rohde ; NHMUK Reg. No. 1982.85 .

Differential diagnosis: Cephalothorax subrectangular, wider than long. Trunk about as long as cephalothorax; anterior part (second and third pedigerous somites) slightly wider than cephalothorax, bearing third legs ventrally (lateral margins of which visible in dorsal view). Posterior part of trunk (fourth pedigerous somite) covered by ovoid and longer than wide dorsal trunk plate, lateral margins of plate convex, entire free posterior margin weakly convex. Urosome comprising fused genital complex and abdomen bearing paired caudal rami. Caudal rami about twice as long as wide; tapering towards blunt apex; rami entirely concealed beneath dorsal trunk plate in dorsal view. Parabasal flagellum absent. Leg 3 located laterally on ventral surface of third pedigerous somite within trunk region, forming horizontally-orientated fleshy lamella, directed posteriorly, with weakly bilobed tip; outer lobe shorter than inner. Leg 4 bilobate; both inner and outer lobes elongate, subequal, protruding well beyond free posterior margin of dorsal trunk plate. Leg 5 as small unarmed lobe. Body length of ♀ ranging from 2.58 to 3.01 mm, with a mean of 2.80 mm (based on 6 specimens); body length of 2 ♂♂ specimens 1.68 and 1.78 mm.

Distribution: Lernanthropus atrox was originally described from Australian waters as parasitic on Chrysophrys auratus (as Pagrus guttalatus ) by Heller (1865). Kabata (1979a) subsequently reported a single male specimen of L. atrox from Acanthopagrus australis (as Mylio australis ) collected at Tangalooma in Moreton Bay by P.C. Young in February 1964. Kabata (1979a) considered L. atrox to be rather rare but we found it to be common on A. australis in Moreton Bay. Roubal (1981) reported L. atrox from the same host caught off northern New South Wales, and Roubal et al. (1983) reported it from Chrysophrys auratus taken off Coffs Harbour. In a more detailed study, Roubal et al. (1996) found a significant difference in the prevalence of L. atrox on C. auratus between the estuarine (prevalence = 18.8%) and the offshore populations (70.1%) at Port Hacking, Sydney. Byrnes (1988) recorded it on A. australis , A. butcheri (Munro, 1949) and A. latus (Houttuyn, 1782) collected at numerous localities around the coast of Australia including: Carnarvon and Broome (WA), Brisbane (QLD), and Coffs Harbour, Newcastle and Eden (NSW).

This species has also been repeatedly recorded in Japanese waters ( Shishido, 1898; Yamaguti, 1936; Shiino, 1955, 1959; Ho & Do, 1985) where it occurs on several sparid fishes including Chrysophrys auratus (as Pagrosomus unicolor ), P. major (Temminck & Schlegel) and Acanthopagrus schlegelii (Bleeker, 1854) (as Sparus macrocephalus and as A. schlegelii ). Lernanthropus atrox has also been reported from China on A. schlegelii (as Sparus macrocephalus ) ( Chin, 1947; Song & Chen, 1976). In Brazilian Atlantic waters, L. atrox was recorded on Pagrus pagrus (Linnaeus, 1758) by Luque (1996), although the geographically disjunct nature of this record invites closer comparison with L. sarbae Kensley & Grindley, 1973 , described from South African waters.

Remarks: Bassett-Smith (1898b) reported L. atrox from Rhabdosargus sarba (as Chrysophrys sarba ) caught at Bunder Abbas in the Persian Gulf but Ho & Do (1985) agreed with Shiino (1955) in suspecting that this Lernanthropus should be attributed to L. sarbae described from the same host caught off South Africa ( Kensley & Grindley, 1973). When describing L. wilsonis Capart, 1941 from Sparus aurata Linnaeus, 1758 caught off the west coast of Africa, Capart (1941) appeared to distinguish between L. atrox as described by Heller (1865) and L. atrox as described by Yamaguti (1936). We follow Ho & Do (1985) in considering Yamaguti’s Japanese material of L. atrox as conspecific with Heller’s.