An annotated list and molecular data on larvae of gryporhynchid tapeworms (Cestoda: Cyclophyllidea) from freshwater fishes in Africa

Abstract

An annotated list of larvae (metacestodes) of gryporhynchid tapeworms (Cestoda: Cyclophyllidea) from freshwater fishes in Africa is provided with numerous new host and geographical records. Newly collected materials from Burundi, Democratic Republic of the Congo, Kenya, Madagascar, Namibia, Senegal, South Africa, Sudan and Zimbabwe practically double the total number of species reported from African fish so far. We confirm the occurrence of 16 species (five unidentified to the species level and most likely representing new taxa) belonging to the genera Amirthalingamia Bray, 1974 (1 species), Cyclustera Fuhrmann, 1901 (2 species), Dendrouterina Fuhrmann, 1912 (1 species), Neogryporhynchus Baer & Bona, 1960 (1 species), Paradilepis Hsü, 1935 (4 species), Parvitaenia Burt, 1940 (5 species), and Valipora Linton, 1927 (2 species). Additionally, metacestodes of four unidentified species of Paradilepis and Parvitaenia are reported from fish for the first time. Rostellar hooks of all species are illustrated and their measurements are provided together with a host-parasite list. The molecular phylogenetic analysis based on partial LSU rDNA sequences offers the first insight into the internal phylogenetic relationships within the family. Together with the morphological observations, the present study provides a taxonomic baseline for future studies on this largely neglected, but widely distributed and relatively frequent, group of parasites of African fishes, including economically important cichlids like tilapias and cyprinids.

Phylogenetic relationships of the family Gryporhynchidae (Cestoda: Cyclophyllidea) inferred through SSU and LSU rDNA sequences

“…However, the genus Parvitaenia was paraphyletic because four isolates of Parvitaenia spp. recovered from two species of freshwater fishes from South Africa (Scholz et al ., 2018) were sister to N . lasiopeius , whereas P .…”

“…One of the morphological traits that is most important for the taxonomy of the Gryporhynchidae, especially for metacestodes that do not have internal organs developed, is the morphology (shape and size) and number of rostellar hooks (Baer and Bona, 1960; Bona, 1975; Scholz et al ., 2004, 2018). However, the hooks of some genera may be similar, which makes identification of some larvae difficult (Scholz et al ., 2018). In contrast, identification of adults and their generic placement are facilitated by difference in strobilar morphology, especially distribution of gonads, position of osmoregulatory canals and gonopores, and structure of terminal genitalia (Bona, 1994).…”

“…1; Parvitaenia sp. 3; and Valipora minuta (Coil, 1950) (LSU; all larvae from fish – see Scholz et al ., 2018). Additionally, sequences of Fimbriaria sp.…”

“…The taxonomy of the Gryporhynchidae has been mainly based on the strobilar morphology (distribution of gonads, position of gonopore, structure of terminal genitalia) and on the morphology of the rostellum, rostellar apparatus and its sheath, and hooks (Bona, 1975; Mariaux et al ., 2017). Identification of larvae (metacestodes) in fish intermediate hosts is based almost exclusively on the morphology of rostellar hooks: their number, shape and size (Scholz, 2001; Scholz and Salgado-Maldonado, 2001; Scholz et al ., 2002, 2004, 2018).…”

“…Scholz et al . (2018) provided the first insight into the internal phylogenetic relationships within the family based on partial sequences from LSU rDNA of nine species of five genera of gryporhynchid larvae (metacestodes) from African fishes. The main objective of the present study was to establish the relationships between the genera of this family by conducting a phylogenetic analysis based on comparative analysis of sequences of the 18S (SSU) and 28S (LSU) from rDNA of tapeworms of 20 species and nine genera.…”