Darwinoplectanum amphiatlanticus, 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 : 11-15

Darwinoplectanum amphiatlanticus n. sp.

(figs. 26–35)

Type host. Eucinostomus melanopterus (Bleecker) .

Site. Gills.

Type locality. Bamboung, Sine Saloum, Senegal (13°49’30.5’’N, 16°31’44’’W) on May 2006.

Other records. E. melanopterus from Bamboung, Sine Saloum, Senegal (13°49’30.5’’N, 16°31’44’’W) collected in May 2006; E. argenteus from Municipality of Porto Belo, State of Santa Catarina, Brazil (27°09’25.12’’S, 48°33’16.75’’W) collected in January 2001; E. argenteus from Municipality of Pontal do Paraná, State of Paraná, Brazil (25°35’28.27’’S, 48°21’10.70’’W) collected in July 2001.

Specimens deposited. Holotype, CHIOC 37546a; 7 paratypes, CHIOC 37546b–d, INPA 588, MPEG 000007– 000008. USNPC 104826; 17 vouchers, CHIOC 37547–37550, INPA 589–592, MPEG 000009–000015, USNPC 104827–104828.

Etymology. The specific name is derived from Greek (amphis = on both sides + atlantikon = the Atlantic [Ocean]) and refers to the occurrence of the species on the southeastern and southwestern Atlantic Ocean.

Comparative measurements. Table 2 .

Description (based on 26 adult specimens): Body fusiform. Tegument smooth. Cephalic margin tapered; poorly developed terminal lobes; three bilateral pairs of head organs. Eyes 4; posterior pair closer together than those of anterior pair; eye granules ovate, elongate, numerous accessory granules at cephalic region at level of pharynx ( Fig. 26 ). Pharynx ovate to subspherical; oesophagus short or absent; intestinal caeca, inward flexure at distal portion. Genital pore posterior to copulatory complex. Male copulatory organ sigmoid originating from ringlike sclerotised base; base with lateral flap (figs. 27–28). Accessory piece with proximal portion expanded, articulation process attached to base of male copulatory organ; distal portion with two rami, serving as a guide to male copulatory organ (figs. 27–28). Testis spherical to subspherical. Germarium elongate, unbranched, distal end parallel to body; oötype not observed; vaginal aperture marginal; vaginal atrium funnel-shape, slightly muscular, narrowing to short descendent tube; seminal receptacle saccate. Vitellarium extending throughout trunk, absent in regions of major reproductive organs. Egg ovate, short filament. Peduncle short to elongate. Haptor bilaterally lobed ( Fig. 26 ). Squamodiscs similar, sub-circular, concentric rows of dumbbell-shaped rodlets becoming progressively more delicate in posterior row, easily lost in preserved specimens. Ventral anchor with elongate deep root, short depressed superficial root, straight shaft and re-curved point; point reaching level of tip of superficial root. Dorsal anchor with elongate deep root, inconspicuous superficial root, straight shaft and re-curved short point. Ventral bar, elongate, with delicate tapered ends. Paired dorsal bar, spatulate. Hooks similar with protruding thumb with slightly depressed tip, delicate slightly depressed point, slender shank; 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 submarginal in lateral haptoral lobes; filamentous hook loop not observed.

Remarks. Darwinoplectanum amphiatlanticus n. gen. n. sp. differs from its congeners in possessing an accessory piece with proximal portion expanded and distal portion with two rami.

Type host. Gerres cireneus (Walbaum) .

Site. Gills.

Type locality. Punta Santiago near Humacao, Puerto Rico, February 1992.

Specimens studied. Holotype, USNPC 83400; 5 paratypes, USNPC 104824; 2 vouchers, USNPC 84667.

Etymology. This species is named for Ms. Patricia A. Pilitt in recognition of her valuable work as Collection Manager of the United State National Parasite Collection (USNPC), Beltsville, Maryland, USA.

Description (based on 6 adult specimens). Body slender, fusiform, total length excluding the haptor 489 (410– 560; n = 5) long, 97 (80–110; n = 5) wide at the level of germarium. Tegument smooth. 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; granules ovate, elongate, presence of accessory granules at cephalic region. Pharynx ovate to subspherical, 40 (33–45; n = 5) in diameter; oesophagus short or absent; intestinal caeca blind, straight. Genital pore posterior to copulatory complex. Male copulatory organ arcuate originating from ring-like sclerotised base, spatulate end, 23 (21–25; n = 4) long. Accessory piece with proximal portion narrow, articulation process attached to base of male copulatory organ; expanded distal portion, 20 (n = 2). Testis not observed. Germarium tubular, elongate, unbranched, distal end parallel to body, 80 (n = 1) long; oötype not observed; Mehlis’ glands branched, stained deep purple; vaginal aperture marginal; vaginal atrium, vaginal tube, seminal receptacle not observed. Vitellarium extending throughout trunk, absent in regions of major reproductive organs. Egg ovate, short filament, 75 (74–76; n = 2) long, 57 (55–58; n = 2) wide. Peduncle short to elongate; pair of glands associated with haptor. Haptor bilaterally lobed, 92 (80–100; n = 5) long, 189 (175–200; n = 5) wide. Squamodiscs similar, sub-circular to subtrapezoidal, concentric rows of dumbbell-shaped rodlets becoming progressively more delicate in posterior row, easily lost in preserved specimens, 83 (75–88; n = 3) long, 103 (100–110; n = 3) wide. Ventral anchor with elongate deep root, short depressed superficial root, straight shaft and re-curved point; point reaching level of tip of superficial root, outer 49 (46–52; n = 3), inner 30 (28–33; n = 5), base 9 (n = 2). Dorsal anchor with elongate deep root, inconspicuous superficial root, straight shaft and re-curved short point, outer 45 (40–49; n = 5), inner 26 (24–27; n = 5), base 6 (n = 2). Ventral bar, elongate, with delicate tapered ends, 8 (8–9; n = 5) long, 108 (96–125; n = 5) wide. Paired dorsal bar, spatulate, 15 (12–18; n = 6) long, 78 (65–90; n = 6) long. Hooks similar with protruding thumb with slightly depressed tip, delicate slightly curved point, slender shank, 10 (10–11; n = 31) 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. Examination of the vouchers of Diplectanum collinsi collected from Gerres cireneus from Puerto Rico (see Bunkley-Williams & Williams 1994) indicates these specimens are members of Darwinoplectanum n. gen., described above as D. pillitae n. gen. n. sp. . The new species differs from all other species in the genus by possessing: (1) a male copulatory organ arcuate with spatulate end; (2) an accessory piece with proximal portion narrow and expanded distal portion; and (3) the size of the haptor and squamodiscs (haptor: 92 long x 189 wide vs. 49 long x 130 wide in D. figueiredoi , and 48 long X 156 wide in D. amphiatlanticus ; squamodiscs: 83 long x 103 wide vs. 64 long x 73 wide in D. figuereidoi , and 48 long X 49 wide in D. amphiatlanticus ).

Figures

FIGURES 26 – 35. Darwinoplectanum amphiatlanticus n. gen. n. sp. 26. Holotype whole-mount (ventral). 27 – 28. Copulatory complex. 29. Hook. 30. Rodlets. 31. Ventral bar. 32. Dextral dorsal bar. 33 – 34. Ventral anchor. 35. Dorsal anchor. Fig. 26 scale of 50 μm; Figs. 27 – 30 scale of 10 μm; Figs. 31 – 35 scale of 25 μm.

Tables

TABLE 2. Comparative measurements (in μm) of specimens of Darwinoplectanum amphiatlanticus n. gen. n. sp. from two species of Eucinostomus from Africa and Brazil, respectively. MCO = male copulatory organ.

* E. melanopterus Africa	N	E. melanopterus Africa	N	E. argenteus Brazil	N
Body Length 362 (350–375) Width 58 (55–65)	3 3	328 (300–355) 53 (45–60)	2 2	327 (200–445) 63 (30–80)	5 4
Haptor Length 48 (45–50) Width 156 (148–160)	3 3	56 (50–63) 126 (115–138)	3 3	56 (50–75) 138 (100–175)	4 4
Pharynx 29 (25–35) MCO 28 (22–35) Accessory piece 26 (20–31) Squamodisc Length 48 (43–50) Width 49 (48–50)	4 4 2 3 3	28 (25–30) 41 29 (26–30) 70 65	2 1 3 1 1	28 (20–35) 22 (20–25) 22 (20–30) 75 (63–88) 73 (58–88)	5 6 5 3 3
Rows – Ventral Anchor Outer 48 (45–51) Inner 32 (24–45) Base 11 (9–13) Dorsal Anchor	– 6 5 4	18 (17–19) 49 (43–55) 29 (26–32) 10 (9–11)	2 6 6 5	19 41 (38–43) 23 (22–23) 9 (7–10)	2 5 5 4
Outer 45 (44–47) Inner 25 (23–26) Base 6 (6–7)	6 6 4	46 (44–47) 25 (24–26) 7 (6–7)	6 6 4	38 (36–40) 21 (19–22) 5	5 5 4
Ventral Bar Length 10 (8–12) Width 109 (101–112) Dorsal Bar Length 13 (11–16) Width 79 (73–86) Hook 10 (9–10) Germarium 48 (47–48) Testis 17 (14–20)	6 5 4 4 12 2 2	10 (8–12) 105 (97–119) 20 (15–27) 78 (74–84) 9 (9–10) 52 (46–55) 28 (25–29)	6 5 3 5 9 3 3	8 (7–9) 74 (72–75) 10 56 (51–65) 9 (9–10) 48 (41–65) 30 (20–40)	5 4 3 4 15 5 2
Egg Length 67 Width 50	1 1	– – –	– – –	– 27 18	– 1 1
* Type series
Darwinoplectanum pilittae n. sp. (figs. 36–43)