Darwinoplectanum figueiredoi, Domingues, Marcus V., Diamanka, Arfang & Pariselle, Antoine, 2011

Domingues, Marcus V., Diamanka, Arfang & Pariselle, Antoine, 2011, Monogenoids (Diplectanidae, Polyonchoinea) from the gills of mojarras (Perciformes, Gerreidae) with the resurrection of Neodiplectanum Mizelle & Blatz, 1941 and the proposal of Darwinoplectanum n. gen., Zootaxa 3010, pp. 1-19 : 9-11

Darwinoplectanum figueiredoi n. sp.

( Figs. 17–25 )

Type host. Eucinostomus argenteus Baird & Girard.

Site. Gills.

Type locality. Municipality of Pontal do Paraná, State of Paraná, Brazil (25°35’28.27’’S, 48°21’10.70’’W) on 16 July 2001.

Specimens studied. Holotype, CHIOC 37545a; 14 paratypes, CHIOC 37545b–f, INPA 593a–c, MPEG 000016–000019, USNPC 104825.

Etymology. This species is named for Dr. José Lima de Figueiredo, Museu de Zoologia da Universidade de São Paulo (MZUSP), São Paulo, São Paulo, Brazil in recognition of his research on taxonomy and systematic of marine fishes from Brazil.

Description (based on 12 adult specimens): Body slender, fusiform, total length excluding haptor 386 (350– 450; n = 7) long, 73 (60–80; n = 7) wide at the level of germarium. Tegument smooth or scaled; scales plate-like with round anterior margins, lightly sclerotised, directed anteriorly, not easily observed in preserved specimens. Cephalic margin tapered; poorly developed terminal lobes; three bilateral pairs of head organs with rod-shaped secretion; cephalic glands not observed. Eyes 4, equidistant; posterior pair larger than anterior pair; eye granules ovate, elongate, numerous accessory granules at cephalic region ( Fig. 17 ). Pharynx ovate to subspherical, 34 (28– 38; n = 6) in diameter; oesophagus short; intestinal caeca, broadly curved. Genital pore opening anterior to copulatory complex. Male copulatory organ slightly straight or arcuate originating from ring-like sclerotised base, marginal flap originating mid-length, 53 (50–55; n = 7) long (figs. 18–19). Accessory piece comprising variable sheath involving male copulatory organ, articulation process attached to base of male copulatory organ; expanded distal portion, 40 (39–42; n = 7) (figs. 18–19). Testis spherical to subspherical. Germarium tubular, elongate, unbranched, distal end transversal or diagonal to body, 40 long; oötype, Mehlis’ glands not observed; vaginal aperture marginal; vaginal atrium funnel-shape, slightly muscular, narrowing to short descendent tube; seminal receptacle not observed. Vitellarium extending throughout trunk, absent in regions of major reproductive organs. Egg not observed. Peduncle short to elongate. Haptor bilaterally lobed, 49 (38–68; n = 6) long, 130 (93–163; n = 6) wide ( Fig. 17 ). Squamodiscs similar, subcircular to subtrapezoidal, 18 (n = 4) concentric rows of dumbbell-shaped rodlets becoming progressively more delicate in posterior row, difficult to observe in preserved specimens, 64 (63–68; n = 5) long, 73 (68–75; n = 4) wide. Ventral anchor with elongate roots (deep root longest), straight shaft and recurved point; point reaching level of tip of superficial root, outer 31 (28–32; n = 6) long, inner 18 (16–20; n = 6), base 8 (7–8; n = 6). Dorsal anchor with elongate deep root, inconspicuous superficial root, straight shaft and recurved short point, outer 28 (24–30; n = 6), inner 17 (14–18; n = 6), base 5 (4–6; n = 6). Ventral bar, elongate, with delicate tapered ends, 12 (10–14; n = 5) long, 128 (123–134; n = 5) wide. Paired dorsal bar, spatulate, 14 (13–15; n = 5) long, 76 (70–80; n = 4) long. Hooks similar with protruding thumb with slightly depressed tip, delicate slightly curved point, slender shank, 10 (9–10; n = 22) long; hook pairs 1–5, ventral, hook pairs 6–7, dorsal; hook pair 1 nearly to ventral bar end; hook pair 5 at level of distal ventral anchor shaft, others sub-marginal in lateral haptoral lobes; filamentous hook loop not observed.

Remarks. Darwinoplectanum figueiredoi n. gen. n. sp. is the type species of the genus. It can be distinguished from its congeners by the position of the genital pore (i.e., anterior the copulatory complex) and the morphology of the copulatory complex. Also, the male copulatory complex of D. figueiredoi is larger than that of its congeners (male copulatory organ: 53 vs. 23 in D. pillitae n. gen. n. sp., and 28 in D. amphiatlanticus n. gen. n. sp.; accessory piece: 40 vs. 20 in D. pillitae n. gen. n. sp., and 26 in D. amphiatlanticus n. gen. n. sp.).

Figures

FIGURES 17 – 25. Darwinoplectanum figueiredoi n. gen. n. sp. 17. Holotype whole-mount (ventral). 18 – 19. Copulatory complex. 20. Squamodisc. 21. Ventral bar (bent at mid-lenght). 22. Sinistral dorsal bar. 23. Hook. 24. Ventral anchor. 25. Dorsal anchor. Fig. 17 scale of 100 μm; Figs. 18 – 19 scale of 10 μm; Figs. 20 – 25 scale of 25 μm.