Sagum petersi (van Beneden, 1857 )

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 : 88-89

Sagum petersi (van Beneden, 1857)

Syn: Lernanthropus petersi van Beneden, 1857

Paralernanthropus petersi (van Beneden, 1857)

Pseudolernanthropus petersi (van Beneden, 1857) Material examined: none.

Differential diagnosis: Cephalothorax about as long as wide, with evenly convex lateral margins. Trunk irregularly subrectangular, wider than cephalothorax: anterior part of trunk (second and third pedigerous somites) wider than long, produced into tapering posterolateral processes extending about 30% of distance along lateral margins of dorsal trunk plate. Posterior part of trunk covered by broad dorsal trunk plate with rounded hexagonal shape. Dorsal surface of cephalothorax and trunk lacking ornamentation. Urosome formed from fifth pedigerous somite, genital complex and abdomen, all fused. Egg sacs loosely coiled beneath dorsal trunk plate. Paired caudal rami short, tapering towards tip. Leg 2 biramous, with unimerous rami. Leg 3 trilobate, with large, lamellate exopodal lobe orientated horizontally across ventral surface, reaching to posterior end of body, connecting via long posteriorlydirected, flagellum-like middle lobe to smaller rounded inner lobe; flagellate middle lobe extending well beyond posterior margin of dorsal trunk plate. Leg 4 bilobate; with inner and outer lobes long and tapering, distal flagellate parts of both lobes extending well beyond posterior margin of dorsal trunk plate. Body length of ♀ about 5.8 mm (from Kabata, 1979a).

Distribution: This species was originally described from Epinephelus fuscoguttatus (Forsskål, 1775) (as Serranus goliath ) caught off Mozambique (van Beneden, 1857). It was also listed as occurring on an unidentified host caught off Zaire by Brian (1939), but in the absence of any voucher specimens or description, this record is in need of confirmation. Kabata (1979a) reported S. petersi on Epinephelus lanceolatus (as Promicrops lanceolatus ) from Queensland waters.

Remarks: This species is not well characterized but the trilobate state of the third leg, with the middle flagellum-like lobe extending beyond the posterior margin of the dorsal trunk plate, as described by Kabata (1979a), is unique within the genus.