Molecular systematics and evolutionary history of catenotaeniid cestodes (Cyclophyllidea)

Hidden diversity of cestodes in wild African carnivores: I. Non-taeniid cyclophyllideans

Our knowledge of parasites in wildlife remains limited, primarily due to restricted access to samples, especially of parasites from protected species. This present study contributes to the comprehension of the enigmatic world of helminths of African wild mammals and cestode biodiversity by combining both molecular and morphological analysis. Cestode samples were opportunistically collected from 77 individual definitive hosts in South Africa, Namibia and Ethiopia, encompassing 15 different species of wild African carnivores and additionally domestic cats. The analysis revealed 32 different cyclophyllidean species of which 21 (65.6 %) represent previously unknown genetic entities. They belong to the families Mesocestoididae, Hymenolepididae, Dipylidiidae and Taeniidae. Here we cover the non-taeniid cestodes, while the taeniids will be addressed in a separate publication. Three of the non-taeniid species uncovered in this study could be assigned to the genus Mesocestoides and were isolated from servals and domestic cats. The white-tailed mongoose was found to be a suitable host for a species belonging to the Hymenolepididae, which was identified as Pseudandrya cf. mkuzii. Both feline and canine genotypes of Dipylidium caninum were detected in domestic cats, the canine genotype also in an African wolf. In addition to these, a novel species of Dipylidium was discovered in an aardwolf. Lastly, four distinct species of Joyeuxiella were found in this study, revealing a cryptic species complex and emphasizing the need for a taxonomic reassessment of this genus. Despite the limited scope of our study in terms of geography and sample size, the results highlight that biodiversity of cestodes in African wild mammals is grossly under-researched and follow-up studies are urgently required, in particular linking morphology to gene sequences.

Spermatological Characterization of the Cestode Meggittina gerbilli (Cyclophyllidea: Catenotaeniidae), a Parasite of Gerbils, Gerbillus gerbillus and Gerbillus campestris (Rodentia: Muridae) in Tunisia

Ultrastructural characters of spermiogenesis and the mature spermatozoon of the cestode Meggittina gerbilli (Cyclophyllidea: Catenotaeniidae), a parasite of the Lesser Egyptian gerbil (Gerbillus gerbillus) and the North African gerbil (Gerbillus campestris) (Rodentia: Muridae) in the Djebel Dahar (South of Tunisia), were studied using transmission electron microscopy. The spermiogenesis of M. gerbilli is of Bâ and Marchand's type III, which is mainly characterized by a proximodistal fusion of a single flagellum with a cytoplasmic extension. In this catenotaeniid, the proximal fusion is preceded by a 90° rotation of the flagellum. The spermatozoon is a Levron et al. type VI, which presents a single axoneme with the 9 + '1' trepaxonematan pattern, a periaxonemal sheath, two crest-like bodies, twisted cortical microtubules, and a spiraled nucleus. The obtained results show similarities with the remaining studied catenotaeniids, namely Catenotaenia pusilla and Skrjabinotaenia lobata. The results are compared and discussed according to several characteristics found in the catenotaeniids and other studied cyclophyllideans.

Systematic position of the enigmatic Quentinia mesovitellinica (Rêgo, 1967) (Cestoda, Cyclophyllidea)

The systematic position of Quentinia mesovitellinica (Rêgo, 1967) (Cestoda, Cyclophyllidea) from the hystricomorph rodent Galea spixii (Wagler) (Caviidae) in Brazil is reevaluated based on published information. Quentinia mesovitellinica is generally thought to belong to the family Catenotaeniidae, being thus the only catenotaeniid cestode parasitizing hystricomorph rodents and also the only catenotaeniid in South America. However, the present study shows that Q. mesovitellinica differs fundamentally from Catenotaenia Janicki, 1904 sensu lato and other catenotaeniids with respect to several morphologic features, but shares these features with Monoecocestus Beddard, 1914 sensu Beveridge (1994), a genus in the family Anoplocephalidae sensu stricto (i.e. sensu Spasskii, 1951). However, Q. mesovitellinica is not assigned here to Monoecocestus, because the latter is a morphologically heterogeneous genus and will probably be split when subjected to a comprehensive phylogenetic and taxonomic analysis. Instead, Quentinia Spasskii, 1969 is considered a valid genus in the family Anoplocephalidae s. s. The morphologically closely related Monoecocestus eljefe Haverkost & Gardner, 2010 from Galea musteloides Meyen in Bolivia is assigned to Quentinia as Q. eljefe (Haverkost & Gardner, 2010) n. comb. An amended diagnosis is provided for Quentinia.

Nematodes and cestodes of rodents in South Africa: baseline data on diversity and geographic distribution

Currently, descriptive information on the host range and geographic distribution of helminth parasites associated with naturally occurring rodents in South and southern Africa is scant. Therefore, we embarked on a countrywide study to: (1) identify gastrointestinal helminths and their host range, and (2) provide baseline data on the geographic distribution of helminths across the country. Altogether, 55 helminth taxa were recovered from at least 13 rodent species (n = 1030) at 26 localities across South Africa. The helminth taxa represented 25 genera (15 nematodes, nine cestodes and one acanthocephalan). Monoxenous nematodes were the most abundant and prevalent group, while the occurrence of heteroxenous nematodes and cestodes was generally lower. The study recorded several novel helminth-host associations. Single-host-species infections were common, although multiple-host-species infections by helminth species were also recorded. Monoxenous nematodes and some cestodes were recovered countrywide, whereas heteroxenous nematodes were restricted to the eastern regions of South Africa. The study highlights the as yet unexplored diversity of helminth species associated with naturally occurring rodent species and provides initial data on their geographical distribution in South Africa.

Beta diversity of gastrointestinal helminths in two closely related South African rodents: species and site contributions

A fundamental aim of parasite ecology is to understand the mechanisms behind spatial variation in diversity and structure of parasite assemblages. To understand the contribution of individual parasite species and their assemblages to spatial variation in parasite communities, we examined species contributions to beta diversity (SCBD) and local contributions to beta diversity (LCBD) of parasitic gastrointestinal helminths (nematodes and cestodes) in two closely related rodents, Rhabdomys dilectus and Rhabdomys pumilio, from 20 localities across South Africa. Although the two Rhabdomys spp. are morphologically similar, they differ substantially in body size, habitat preference, and sociality. We asked whether the variation in life history traits and infection parameters are associated with SCBD of helminths and whether variation in environmental factors, host population density, and species richness of host communities are associated with LCBD of component assemblages of helminths. We also considered spatial factors to test whether LCBD of helminth assemblages demonstrate geographic structure. We found that the contribution of helminth species parasitic in both hosts to beta diversity significantly increased with characteristic prevalence of these species, whereas mean abundance, type of life cycle, and location in the host's gut had no effect on SCBD. The LCBD of helminth assemblages showed a significant positive correlation with environmental factors in both host species. Our results suggest that predictors of variation in SCBD and LCBD may substantially differ between parasites with different infection parameters and/or parasite communities at different hierarchical scales.