Callorhynchocotyle marplatensis Suriano & Incorvaia, 1982

Vaughan, David & Christison, Kevin, 2012, Towards addressing the current state of confusion within the Hexabothriidae Price, 1942 (1908): Callorhynchocotyle Suriano & Incorvaia, 1982 (Monogenea: Hexabothriidae) re-visited, with the preliminary evaluation of novel parameters for measuring haptoral armature of hexabothriids, Zootaxa 3229, pp. 1-34 : 15-18

Callorhynchocotyle marplatensis Suriano & Incorvaia, 1982

( Figs 5 , 6 , Tables 1, 2)

Synonyms: Callorhynchocotyle callorhynchi Suriano & Incorvaia, 1989 ; Callorhinchocotyle callorhynci Suriano & Incorvaia, 1989.

Type host. Callorhinchus callorhynchus (Linnaeus) ( Callorhynchidae , Holocephali).

Type locality. Mar Del Plata coastal region, Argentina, South America (38°S; 57°W).

Additional locality. Uruguay coastal region, South America (Boeger et al. 1989).

Site on host. Gills.

Material examined. USNPC 080279.00: vouchers M1496-1, 6, 7 and 10.

Redescription. Total body ( Fig. 5 A) length (excluding haptor) 9750 ± 1021.4(8300–10600, n = 4), maximum body width 917 ± 171.6(683–1095, n = 4). Oral sucker ( Fig. 5 A) non-papillate, diameter 335 ± 36.5(290–365, n = 4). Pharynx 75 ± 5.8(67–81, n = 4) long, 79 ± 5.3(72–84, n = 4) wide ( Fig. 5 A). Branched intestinal caeca unite posterior to testes and extend into haptor ( Fig. 5 A). Asymmetrical haptor 2930 ± 995.7(1933–3920, n = 4) long, 1225 ± 646.5(277–1640, n = 4) wide with 3 paired sucker sclerite complexes sensu Boeger et al. (1989). Haptoral suckers non-papillate.

Sucker sclerites of complex 3 ( Fig. 6 A): circumference length 1197 ± 42.9(1149–1249, n = 4); total length 535 ± 27.2(503–562, n = 4); total diameter 336 ± 17.0(314–355, n = 4); width 69 ± 6.5(60–76, n = 4); shaft length 506 ± 21.6(480–528, n = 4); inner diameter 269 ± 11.1(255–280, n = 4); aperture angle 56° ± 4.5(50°–61°, n = 4); aperture 302 ± 25.8(278–332, n = 4); hook-side curve length 116 ± 3.3(113–120, n = 4) and shaft-side curve length 134 ± 6.3(123–141, n = 4). Complex 3 sucker-sclerite hook length 172 ± 5.3(168–180, n = 4); hook curve length 30 ± 7.7(23–41, n = 4); aperture 138 ± 3.7(134–142, n = 4) and base width 46 ± 5.0(41–53, n = 4).

Sucker sclerites of complex 2 ( Fig. 6 B): circumference length 1244 ± 43.9(1206–1306, n = 4); total length 541 ± 22.7(511–566, n = 4); total diameter 344 ± 22.8(320–374, n = 4); width 66 ± 8.2(59–78, n = 4); shaft length 523 ± 26.0(498–559, n = 4); inner diameter 280 ± 14.0(265–299, n = 4); aperture angle 54° ± 2.5(51°–57°, n = 4); aperture 303 ± 19.0(278–381, n = 4); hook-side curve length 105 ± 9.5(99–119, n = 4) and shaft-side curve length 140 ± 5.5(135–147, n = 4). Complex 2 sucker-sclerite hook length 153 ± 12.0(145–171, n = 4); hook curve length 30 ± 3.3(28–35, n = 4); aperture 121 ± 9.9(110–134, n = 4) and base width 38 ± 3.5(35–43, n = 4).

Sucker sclerites of complex 1 ( Fig. 6 C) smaller than similarly sized sucker sclerites of complex 2 and 3 with circumference length 922 ± 30.7(896–966, n = 4); total length 418 ± 11.6(401–423, n = 4); total diameter 262 ± 20.1(233–280, n = 4); width 42 ± 5.3(35–47, n = 4); shaft length 420 ± 9.2(408–427, n = 4); inner diameter 222 ± 15.3(199–232, n = 4); aperture 270 ± 18.7(256–297, n = 4); hook-side curve length 68 ± 4.0(64–72, n = 4) and shaft-side curve length 101 ± 14.0(88–114, n = 4). Complex 1 sucker-sclerite hook length 59 ± 4.4(54–64, n = 4); hook curve length 15 ± 1.1(13–16, n = 4); aperture 47 ± 5.3(40–53, n = 4) and base-width 16 ± 0.8(15–17, n = 4).

Dorsal haptoral appendix 1655 ± 124.7(1514–1773, n = 4) long, 286 ± 48.4(223–337, n = 4) wide. Terminal suckers of appendix 232 ± 28.4(193–264, n = 6) long, 141 ± 20.0(120–167, n = 6) wide. Pair of hamuli between appendix terminal suckers ( Fig 5 A).

Hamulus ( Fig. 5 B) total length 58 ± 3.3(56–61, n = 2); hook point length 14 ± 0.3, n = 2; hook shank length 17 ± 0.1, n = 2; total diameter 26 ± 2.0(25–28, n = 2); hook distal point width 4 ± 0.2, n = 2; outer aperture angle 17° ± 0.1(n = 2); inner aperture angle 67° ± 18.2(54°–80°, n = 2); aperture 88 ± 19.6(74–102, n = 2); hook shank base width 6 ± 0.6, n = 2; inner root-shaft length 45 ± 1.7(44–46, n = 2); outer root-shaft length 41 ± 3.9(38–44, n = 2); root base angle 105° ± 4.4(102°–108°, n = 2), and root base width 23 ± 0.9(23–24, n = 2).

Testes irregular in shape, 83 ± 18.6(65–107, n = 4) in number; 95 ± 9.1(83–109, n = 10) wide. Vas deferens sinuous, surrounded by small gland cells along the majority of its length ( Fig. 5 B).

Presence of vas deferens loop proximal to entrance into cirrus ( Fig. 5 B) obscured in some specimens. Unarmed muscular cirrus total length 410 ± 29.6(374–447, n = 4); maximum width 38 ± 4.0(34–44, n = 4); distal bulb length 67 ± 2.6(65–70, n = 4), and distal bulb width 62 ± 3.0(58–66, n = 4). Area of ventral tegument surrounding distal portion of cirrus, weakly indented ( Fig. 5 B).

Ovary (dextral = 2, sinistral = 2) 1422 ± 141.9(1265–1530, n = 4) long, anteriorly lobate, coiled posteriorly, ascending to oviduct, branching to sac-like, reduced seminal receptacle ( Fig. 5 C). Ootype smooth, leading to uterus, dorsal to ovary, ventral to vas deferens ( Fig. 5 C). Ovate eggs connected by tendrils at each pole ( Fig. 5 B). Eggs (in uterus) 154 ± 5.2(146–165, n = 13) long, 67 ± 7.5(57–83, n = 13) wide. Parallel vaginal ducts with glandulo-muscular distal portion and thin-walled proximal portion ( Fig. 5 B). Ventral vaginal pores muscular, lateral to proximal portion of cirrus ( Fig. 5 B). Follicular vitellarium originates posterior to vaginal pores. Excretory pores marginal and anterior to vaginal pores ( Fig. 5 B).

Remarks. A discrepancy exists in the total length measurements between all sucker sclerites of Suriano & Incorvaia (1982), those of Boeger et al. (1989) and the present study. It is unclear how the total length measurements of the sucker sclerites were measured in Suriano & Incorvaia (1982). However, it is likely these measurements are erroneous as they are more than twice the length of those for Boeger et al. (1989) who reviewed the holotype, and nearly twice the length of those measured in the present study. The scale bar given for sucker sclerites of C. marplatensis by Suriano & Incorvaia is 0.05mm (50µm). The scale bar is drawn to equate to sucker complex sclerite length but is inaccurate. It is likely that the sucker complex sclerite measurements of Suriano & Incorvaia (1982) were miscalculated.

Boeger et al. (1989) redescribed C. marplatensis adding additional voucher material collected off Uruguay and Argentina from the type host Callorhinchus callorhynchus . They amended the original description of Suriano & Incorvaia (1982) to include the presence of a “weak genital sucker” and the lack of papillae in both the oral and haptoral suckers. Beverley-Burton & Chisholm (1990) disputed the existence of this genital sucker after examination of the same voucher material used for the present redescription (USNPC 080279.00) adding that since it was lacking this feature was questionable as a diagnostic character. In the present study, examination of voucher M1496-10 revealed the presence of the “weak genital sucker” of Boeger et al. (1989). However, its function as a true sucker is questionable. The structure surrounds the position of the distal portion of the cirrus and is likely a weak indentation of the ventral tegument in this region ( Fig. 5 A, B).

Suriano & Incorvaia (1982) indicated the presence of many small cuticular tubercles (papillae) on the inner surface of the oral sucker in the original description of C. marplatensis . Boeger et al. (1989) redescribed C. marplatensis with a non-papillate oral sucker which is confirmed in the voucher specimens examined for the present study.

Callorhynchocotyle marplatensis can be distinguished from all of the other species of Callorhynchocotyle by the lack of papillae in the haptoral suckers and oral sucker and is found exclusively on the host Callorhinchus callorhynchus .

Boeger et al. (1989) in their redescription of C. marplatensis included the synonyms C. callorhynchi and C. callorhyncy . Both synonyms were discussed in error in the original description of Suriano & Incorvaia (1989).

Figures

FIGURE 5. Callorhynchocotyle marplatensis. A. Whole mount. B. Enlarged anterior section of whole mount. C. Enlarged mid-section of whole mount. Abbreviations: ao, anterior section of ovary; ap, appendix; ci, cirrus; dv, distal portion of vagina; eg, egg; ep, excretory pore; i, intestinal caecum; ivt, indentation of ventral tegument surrounding ovate distal cirrus; ji, junction of caeca posterior to testes; oot, ootype; os, oral sucker; p, pharynx; po, posterior section of ovary; sr, seminal receptacle; t, testes; vas, vas deferens; vd, vitteline duct; vp, vaginal pore; 1 – 3, sucker-sclerite complexes 1 – 3. Scale bars = 1000 µm.

FIGURE 6. Callorhynchocotyle marplatensis sucker sclerites of complexes 1 (A), 2 (B) and 3 (C), and hamulus (D). Scale bars: A = 260 µm, B, C = 340 µm, D = 60 µm.