Pseudorhabdosynochus duitoe Justine, 2007

Sigura, Aude & Justine, Jean-Lou, 2008, Monogeneans of the speckled blue grouper, Epinephelus cyanopodus (Perciformes, Serranidae), from off New Caledonia, with a description of four new species of Pseudorhabdosynochus and one new species of Laticola (Monogenea: Diplectanidae), and evidence of monogenean faunal changes according to the size of fish, Zootaxa 1695, pp. 1-44 : 27

Pseudorhabdosynochus duitoe Justine, 2007

Type host: Epinephelus maculatus (Bloch) (Serranidae) .

New host: Epinephelus cyanopodus Richardson (Serranidae) .

Site: Between secondary gill lamellae.

Material examined: 8 specimens: 2 ‘picrate’ (p), 6 ‘unflattened carmine’ (uc).

Comparative material examined: Type specimens, MNHN .

Material deposited: vouchers, MNHN JNC 1659, 1902.

Prevalence: 18 % (3/17) in all fish (Table 2); 0% (0/12) in large fish with ‘specific’ fauna ( Table 10); 33% (1/3) in small fish with ‘foreign’ fauna ( Table 10).

Intensity: See Table 2; maximum calculated intensity 10; this species represented 0.5% of the total number of monogeneans.

Short description. [Limited to selected measurements of 5 uc specimens from JNC 1902 and 1 p specimen from JNC 1659, measurements in original description indicated as OD]. Quadriloculate organ inner length uc 46 (44–48), p 43, OD 46; cone length uc 7 (5–9), p 9, OD 9; tube length uc 18 (17–19), p 17, OD 20; sclerotised vagina total length uc 24 (23–25), p 25, OD 24; lateral (dorsal) bar length uc 48 (45–54), p 50, OD 49; ventral bar length, uc 66 (63–67), p 72, OD 72. Structure of sclerotised vagina very similar to that of specimens from the type-host. The specimens were mature with fully developed ovary and testis, and one had an egg in the uterus.

Remarks. Based on the structure of their sclerotised vagina, quadriloculate organ and their measurements, these specimens are similar to the type-specimens of P. duitoe from the type-host, E. maculatus .

These specimens are considered to be the result of infection of young specimens of E. cyanopodus by infective stages of P. duitoe originating from another species of grouper, E. maculatus , which shares the same environment as young E. cyanopodus . Although apparently ‘accidental’, this infection produces adult monogeneans. However, these species were never encountered in older E. cyanopodus which harbour other species. See paragraph about the role of spawning aggregation on monogenean infection.