Pseudorhabdosynochus cyanopodus, Sigura & Justine, 2008

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 : 6-11

Pseudorhabdosynochus cyanopodus n. sp.

( Figs 2–4)

Type host: Epinephelus cyanopodus (Richardson) (Serranidae) .

Type locality: Lagoon off Nouméa, New Caledonia .

Site: Between secondary gill lamellae.

Type specimens: Holotype, JNC1660 A3, Passe de Dumbéa , off Nouméa, New Caledonia (22°20’S, 166°15’E, 25.xi.2005).

Material examined: 141 specimens, including 52 ‘carmine’ (c) and 17 ‘picrate’ (p).

Material deposited: Holotype (c) and 87 paratypes (26 c, 44 uc, 17 c), MNHN, JNC546 , 1625 , 1626 , 1660 , 1661 ; paratypes, BMNH 2007.11.23.1. (c), 2007.11.23.2 (uc); USNPC 100398 (c), 100399 (uc); SAMA

AHC 29294 (c), 29295 (uc); HCIP M-457 (1 c, 1 uc); SZU 2007112101-1 (c), 2007112101-2 (uc).

Prevalence: 82 % (14/17) in all fish (Table 2); 100% (12/12) in large fish with ‘specific’ fauna ( Table 10).

Intensity: See Table 2; maximum calculated intensity 68; this species represented 9% of the total number of monogeneans.

Etymology: From the host name.

Description. Body wide; length h 360, c 501±96 (340–700, n = 34), width h 310, c 329±45 (240–410, n = 25). Tegument scaly; posterior region with scales on ventral and dorsal faces from squamodiscs to level of ovary and testis. Anterior region with 3 pairs of head organs and 2 pairs of eye-spots; distance between outer margins of anterior eye-spot pair h 25, c 37±9.2 (22–64, n = 35), of posterior eye-spot pair h 21, c 31±9.2 (20– 59, n = 38).

Haptor differentiated from rest of body, less wide than body, width h 185, c 185±18 (150–230, n = 36), provided with 2 similar squamodiscs, 2 pairs of lateral hamuli, 3 bars and 14 marginal hooklets.

Squamodiscs round in shape, made up of rows of rodlets; central rows forming closed ovals; rodlets crenate in central rows; rodlets progressively thinner from centre to periphery; rodlets adjacent in all rows except last row; last row with very thin, separated rodlets; ventral and dorsal squamodiscs similar; ventral squamodisc length h 74, c 66±6.4 (52–78, n = 35), width h 70, c 70±3.8 (63–77, n = 36), with h 15, generally 14 (11–16, n = 36) rows of rodlets and 0–1 closed oval; total number of rodlets h 192, mean 175 (162–192, n = 8, individual variations in Table 3); dorsal squamodisc, length h 77, c 68±6.0 (60–83, n = 31), width h 66, c 66±4.2 (60–80, n = 33), with h 15, generally 15 (12–15, n = 34) rows of rodlets and 0–2 closed ovals; total number of rodlets h 164, mean 169 (156–178, n = 8, individual variations in Table 3).

* Drawn in figs 4 A, B; v, central row ‘v-shaped’ almost close; i, incomplete row.

Ventral hamulus with thick handle and distinct guard, outer length h 36, c 38±2.0 (31–42, n = 67), p 40±1.7 (37–45, n = 31), inner length h 32, c 31±1.4 (27–34, n = 59), p 32±1.6 (29–36, n = 31). Dorsal hamulus with indistinct guard, outer length h 35, c 35±1.6 (30–38, n = 76), p 35±1.0, (32–36, n = 31), inner length h 20, c 22±1.3 (19–25, n = 69), p 21±0.9 (20–24, n = 31). Dorsal (lateral) bars straight, with flattened medial extremity and thick cylindrical lateral extremity, length h 60, c 59±3.3 (47–64, n = 76), p 61±2.8 (55–67, n = 31), maximum width c 13±2.0 (8–18, n = 66), p 16±1.4 (12–18, n = 31). Ventral bar flat, with slightly constricted median portion and blunt extremities, length h 84, c 83±3.9 (74–90, n = 38), p 87 (74–93, n = 16), maximum width h 10, c 11±1.5 (8–15, n = 38), p 13 (9–15, n = 16); groove visible on its ventral side.

Pharynx subspherical, length h 37, c 45±4.2 (35–54, n = 38), width h 37, c 38±4.5 (30–52, n = 38). Oesophagus apparently absent, such that intestinal bifurcation immediately follows pharynx. Caeca simple, terminate blindly at level of posterior margin of vitelline field.

Testis subspherical, intercaecal, length h 50, c 66±20 (25–110, n = 30), width h 116, c 101±32 (38–160, n = 30). Vas deferens emerges from antero-sinistral part of testis, enlarges into seminal vesicle; seminal vesicle in middle region of body, transforms into duct; duct forms bends then transforms into small bulb, followed by duct; duct enlarges then connects with quadriloculate organ. Prostatic reservoir small, connects with quadriloculate organ. Quadriloculate organ with fourth (posterior) chamber slightly more sclerotised than 3 anterior chambers; first chamber with very thin anterior wall; fourth chamber ends in short sclerotised cone, prolonged by sclerotised tube; tube slightly wider at extremity than at base; end of tube prolonged by thin unsclerotised filament of variable length. Inner length of quadriloculate organ h 53, c 51±1.9 (47–55, n = 38), p 61 (55–69, n = 15); cone length h 8, c 7±1.1 (6–10, n = 38), p 6 (5–8, n = 15); tube length h 27, c 26±1.6 (22–29, n = 39), p 26 (24–29, n = 14); tube diameter at base h 4, c 4±0.5 (3–5, n = 38), p 5 (4–5, n = 15); tube diameter at extremity h 5, c 5±0.5 (4–6, n = 38), p 5 (5–6, n = 15); filament length h 17, c 0–21 (n = 36), p 0– 21 (n = 14).

Ovary subequatorial, intercaecal, pre-testicular, encircles right caecum. Ovary width h 70, c 77±26 (28– 150, n = 33). Oviduct passes medially to form oötype, surrounded by Mehlis’ gland; oötype short, opens into uterus. Uterus dextral. Unsclerotised vagina inconspicuous, elongate ( Figure 3L). Duct from sclerotised vagina to oötype inconspicuous. Vitelline fields extend posteriorly from posterior to pharyngeal level in 2 lateral bands, confluent in post-testicular region and terminate anterior to peduncle. Bilateral connections from vitelline fields to oötype inconspicuous. Egg elongate, uc 88 x 31 (80–100 x 25–37, n = 5).

Sclerotised vagina (nomenclature of parts according to Justine 2007a; see Figure 12) sinistral, a complex sclerotised structure; aspect changes according to specimen and orientation ( Figure 3). Sclerotised vagina comprises anterior trumpet, followed by straight primary canal, primary chamber and secondary chamber; trumpet in continuity with unsclerotised vagina ( Figure 3L); primary canal cone-shaped; wall progressively thinner from anterior to posterior part; canal continues into primary chamber; primary chamber large, ovoid, aligned and in continuity with primary canal; wall thick; interior crest within primary chamber, transversal, approximately at mid-length; crest sometimes looking like an interior wall, but the chamber is probably never separated in two parts; secondary canal inserted on anterior part of primary chamber; secondary chamber sclerotised, spherical, ventral to primary chamber; accessory structure, curved, weakly sclerotised, inserted on secondary chamber and directed anteriorly. External surface of primary chamber smooth, internal surface of anterior part of primary chamber and of primary canal with irregular ornamentations. Duct from sclerotised vagina to oötype connects to secondary chamber ( Figs 3L, N, O). Total length of sclerotised vagina h 35, c 38±2.1 (34–41, n = 38), p 41 (34–44, n = 16); external length of primary chamber h 20, c 21±2.0 (17–29, n = 38), p 24 (21–25, n = 16); internal maximum width of primary chamber h 13, c 14±1.1 (12–16, n = 38), p 16 (13–19, n = 16); external maximum width of primary chamber h 16, c 16±0.9 (14–18, n = 38), p 19 (16– 22, n = 16); internal maximum width of secondary chamber h 6, c 6±0.4 (5–6, n = 38), p 6 (5–7, n = 16).

Amorphous material often present within primary chamber. Orientation of sclerotised vagina: trumpet always anterior.

Differential diagnosis. See after P. podocyanus .