Species of Hexabothriidae (Monogenea) may have extensive distribution ranges reflecting multiple host species: evidence from three new South African records Author Vaughan, David B. 0000-0002-4914-5003 Coastal Marine Ecosystems Research Centre, Central Queensland University, Rockhampton, Queensland, Australia. d.b.vaughan@cqu.edu.au Author Christison, Kevin W. 0000-0001-9879-3405 Department of Forestry, Fisheries and Environment, Aquaculture Innovation and Technology Development, Cape Town, South Africa. http: // orcid. org / 0000 - 0001 - 9879 - 3405 & Department of Biodiversity and Conservation Biology, University of the Western Cape, Cape Town, South Africa. Author Hansen, Haakon 0000-0003-1400-9615 Norwegian Veterinary Institute, Fish Health Research Group, Pb 64, N- 1431 Ås, Norway. http: // orcid. org / 0000 - 0003 - 1400 - 9615 Aquatic Parasitology Laboratory and Southeastern Cooperative Fish Parasite & Disease Laboratory, School of Fisheries, Aquaculture, & Aquatic Sciences, College of Agriculture, Auburn University, 559 Devall Drive, Auburn, AL 36832, USA. Author Bullard, Stephen A. 0000-0002-4914-5003 Department of Zoology, School for Environmental Sciences and Development, North-West University, Private Bag X 6001, Potchefstroom, 2520, South Africa. https: // orcid. org / 0000 - 0001 - 6681 - 7724 d.b.vaughan@cqu.edu.au text Zootaxa 2023 2023-03-10 5254 2 151 180 http://dx.doi.org/10.11646/zootaxa.5254.2.1 journal article 233754 10.11646/zootaxa.5254.2.1 5ec5feba-d119-472c-8d9e-a20b6dd9453a 1175-5326 7727255 3B5279F6-8157-4DB1-BFE5-8391D7330D53 Erpocotyle catenulata (Guberlet) Yamaguti Synonyms: Squalonchocotyle catenulata Guberlet ; Neoerpocotyle catenulata (Guberlet) Price Description ( Figs. 1–3 ; Tables 1 , 2 ) [Based on two specimens ] Body elongate ( Fig. 1A ), body-proper 8088 (8035; 8142) long, 2313 (2121; 2504) maximum width. Oral sucker 595 (566; 624) long, 771 (757; 784) wide, with papillate posterior ventral inner portion ( Fig. 1A ); papillae not easily observed. Pharynx muscular, ovoid, 105 (104; 106) long, 123 (116; 130) wide, leading immediately to intestinal caecal bifurcation ( Fig. 1A ). Caecal branches initially narrow, posterolaterally directed post-bifurcation, expanding abruptly at anterior region of vitellarium, extending posteriorly ( Fig. 1A ). Numerous large laterally directed diverticula present along length of caecal branches for length of body-proper; fewer, shorter medially directed diverticula present for length of testicular field ( Fig. 1A ). Caecum confluent posteriorly as it exits body-proper, enters haptor, bifurcating at mid-point of haptor ( Fig. 1A ), non-diverticular branch extending along haptoral median to between sucker sclerite complex pair 1, diverticular branch extending along length of appendix up to position of hamuli ( Fig. 1A ). Haptor large, symmetrical ( Fig. 1A ) 3627 (3213; 4042) long, 3510 (3297; 3724) wide excluding appendix.Appendix marginal ( Fig. 1A ), 2971 (2647; 3095) long, 897 (855; 939) wide, terminating in pair of suckers 479 (434; 525) long, 328 (318; 337) wide. Three pairs of sucker-complex sclerites of approximately the same size positioned bilateral-symmetrically within haptor; pair of sucker complex 3 slightly smaller in total length than 1 and 2 ( Fig. 1B ). Detailed measurements of sucker sclerites of complex 1, 2 and 3 and hamuli are given in Table 1 ; sucker sclerite circumference length measured along curve. Hamuli ( Fig. 1C ), positioned medially within appendix between appendix suckers, immediately after termination of caecum ( Fig. 1A ). Testes 63 (62; 64) in number, occupying intercaecal space posterior to ovary; each testis irregular to ovoid in shape ( Fig. 1A ), 87 (82; 93) in diameter. Proximal part of vas deferens located in anterior half of body-proper, receiving two vasa efferentia. Vas deferens sinuous, wider and more convoluted for its first half, extending anteriorly just right of body mid-line, then narrowing and following roughly along body mid-line to base of unarmed male copulatory organ ( Figs. 1A , 2 ). Male copulatory organ, total length 384 (358; 410), 81 (74; 88) wide at widest point, separated into two distinct parts: proximal prostatic region with many prostatic cells ( Fig. 2 ), initially internally bilobed proximally, narrowing anteriorly to simple tube communicating directly with thick-walled, inflated unarmed distal region of true cirrus 287 (256; 317) long ( Fig. 2 ). Common genital pore immediately ventral to distal part of cirrus. Unarmed vaginal pores ventral, lateral to posterolateral of common genital pore ( Fig. 1A ). Vaginae parallel, individual posterior pathways obscured by vitelline field, join separately and form bilateral commissure with transverse vitelline duct in body mid-region ( Figs. 1A , 3 ). Ovary conspicuous, 2314 (2259; 2368) long; anterior portion with short branches, left of body mid-line; straight descending branch initially left of body mid-line, crossing mid-line at single posterior bend before turning anteriorly, narrowing to simple oviduct ( Figs. 1A , 3 ). Proximal part of oviduct connects with short duct originating from large allantoid seminal receptacle 689 (516; 861) long, 237 (182; 292) wide ( Figs. 1A , 3 ). Seminal receptacle positioned obliquely medial, anterior of posterior bend of ovary ( Figs. 1A , 3 ). Common vitelline duct extends posteriorly, medially and then left, forming commissure with gastrointestinal canal on left, ovovitelline duct on right ( Fig. 3 ). Ovovitelline duct enters base of ô type containing Mehlis’ glands ( Figs. 1A , 3 ). Ô type tubular, dorsal to vitelline ducts, 772 (731; 813) long, 88 (88; 89) wide at widest point, extends anteriorly beyond transverse vitelline duct before making abrupt fold posteriorly, forming long convoluted distal part of oviduct looping back on itself twice anteriorly before giving rise to uterus, immediately anterior to ô type ( Figs. 1A , 3 ). Uterus ventral to vas deferens, 4316 (4223; 4409) long, straight, containing chain-linked eggs in one specimen (not illustrated), eggs in utero ovoid, 165 long, 67 wide, excluding connected polar filaments. Vitelline field extends from area posterior to vaginal pores, overlapping length of intestinal caecum through body-proper and into haptor and haptoral appendix ( Fig. 1A ). Type-host: Mustelus laevis (Linnaeus) , now Mustelus mustelus (Linnaeus) , Triakidae . Additional host: Galeorhinus galeus (Linnaeus) , Triakidae . Type-locality: “Vicinity of Naples”, Italy ( Guberlet 1933 ). Additional localities: West coast of South Africa (host = M. mustelus ), De Mond, South Coast of South Africa , S34º42’39.83” ; E20º06’ `7.37” (host = Ga. galeus ) [present study]; Norway ; Sète, France ; Portugal ; Tunisia ( Brinkmann 1952 ; Euzet 1955 ; Tendeiro and Valdez 1955 ; Lambert and Maillard 1979 ). Location on host: Gill lamellae. Specimens: SAMA AHC 36931 (ex M. mustelus ); 36932 (ex Ga. galeus ).