Morphological polymorphism in tapeworms: redescription of Caryophyllaeus laticeps (Pallas, 1781) (Cestoda: Caryophyllidea) and characterisation of its morphotypes from different fish hosts

Abstract

Recent morphological and molecular data have shown that one of the most common parasites of freshwater fish in the Palaearctic Region, the cestode Caryophyllaeus laticeps (Pallas, 1781) (Eucestoda: Caryophyllidea), is highly polymorphic. Five distinct morphotypes of C. laticeps, largely corresponding to different fish hosts and representing separate, yet closely related genetic lineages, have been recognised and they are characterised in the present paper. Morphotype 1 from breams, Abramis brama (L.) (type-host) and Ballerus spp., corresponds to the original Taenia laticeps Pallas, 1781 and its neotype (paragenophore ex A. brama in Russia) is designated. This morphotype is characterised by a slender body and flabellate scolex. Morphotype 2 was found in the Macedonian vimba Vimba melanops (Heckel) and the vimba bream V. vimba (L.); it is typified by a more robust body, with most anterior extent of the vitelline follicles near the scolex and the cirrus-sac situated more anteriorly than in other morphotypes. Morphotype 3 is represented by worms from the common carp Cyprinus carpio L. that possess a cuneicrispitate scolex (having the form of a wedge with shallow indentations on anterior margin). Morphotype 4 from the common nase Chondrostoma nasus (L.) has a large, robust body and a wide scolex with numerous superficial grooves (wrinkles) in its anterior part. Morphotype 5 is represented by worms from the white-eye bream Ballerus sapa (Pallas); its typical characteristics are a festoon-like anterior margin of the scolex, the absence of vitelline follicles posterior to the cirrus-sac and the absence of a well-developed internal seminal vesicle. Discriminant analysis of 15 morphometric variables readily separated Morphotypes 3, 4 and 5 and confirmed the key discriminating power of traits related to the reproductive system, especially the terminal reproductive organs. Morphological polymorphism and the genetic divergence of different morphotypes of C. laticeps correspond to its wide spectrum of fish definitive hosts and a large distribution area that includes Europe, most of Palaearctic Asia and northern Africa.

Scolex morphology of monozoic tapeworms (Caryophyllidea) from the Nearctic Region: taxonomic and evolutionary implications

“…Brabec et al (2012) included in their phylogenetic analyses only three Nearctic taxa, namely Glaridacris catostomi, Hunterella nodulosa and Promonobothrium hunteri (as Monobothrium hunteri Mackiewicz, 1963), all of the family Caryophyllaeidae. Scholz et al (2015) and Oros et al (2016) enlarged the number of species of Promonobothrium, but no representatives of other Nearctic genera were analysed. Therefore, it is not possible to reliably assess the homology of individual types of scoleces of Nearctic caryophyllideans, which possess structures absent in species from other zoogeographical regions (Mackiewicz 1972, Oros et al 2010.…”

“…Newly collected specimens of 31 species (see below for the list of species) were processed for light (LM) and scanning elec-tron microscopical (SEM) observations. Methods of processing were the same as previously reported in detail (Oros et al 2010, 2016, Scholz et al 2015. Briefly, worms were removed from the intestine of freshly killed fish host, rinsed in saline, fixed with hot (almost boiling) 4% neutral buffered formaldehyde solution (= 10% buffered formalin).…”

Morphological variation of Aplectana hylambatis (Nematoda: Cosmocercidae) from different anuran hosts and localities in Argentina

“…Variations in the presence/absence, form, number and type, arrangement, and measurements of different structures have been studied in numerous groups of organism. These variations have been well documented for different groups of parasites as protozoans (Reece et al 2009, Mideo and Reece 2012, Hussain et al 2013, microsporidians (Vizoso and Ebert 2005), monogeneans (Matejusová et al 2002, Mladineo et al 2013, Brazenor et al 2018, digeneans of invertebrates (Poulin 2003) and of vertebrates (Blankespoor 1974, Kohn et al 1997, Hildebrant et al 2015), cestodes (Barčák et al 2014, Hanzelová et al 2015, Benesh and Kalbe 2016), pentastomids (Kelehear et al 2011, and mites (Downes 1990, Korallo-Vinarskaya et al 2015, among others.…”

Murat Nehri ve Kollarında (Doğu Anadolu Bölgesi, Türkiye) Yaşayan Musul İnci Balığı (Alburnus mossulensis)'nın Metazoan Parazitlerinin Mevsimsel Enfeksiyonu

“…C. laticeps on A. mossulensis was a new record in studies related to freshwater fish parasites in Turkey. The international records about C. laticeps are; Kulakovskaya (1961;1964), Kennedy (1968), Bombarová and Špakulová (2015), Hanzelová et al (2015) and Xi et al (2016).…”