Prospects for elucidating the phylogeny of the Apicomplexa

Abstract

Summary :The Apicomplexa is traditionally considered to contain four clearly defined groups, but the phylogenetic relationships among these groups, and their subsequent taxonomic arrangement, are currently unclear. Here, I consider five of the important criteria that need to be met before radical taxonomic changes are made, in relation to phylogenetic analyses. Unfortunately, at least four of these criteria indicate that the prospects for elucidating the phylogeny and taxonomy of the Apicomplexa are not good in the short term. A lot more pertinent data need to be collected, both in terms of taxa sampled and genes sequenced, before any concordance among phylogenies is likely to emerge; and someone (e.g. a consortium) needs to co-ordinate the active collection and analysis of these data if any worthwhile progress is to be made.

Intestinal coccidiosis of anadromous and landlocked alewives, Alosa pseudoharengus, caused by Goussia ameliae n. sp. and G. alosii n. sp. (Apicomplexa: Eimeriidae)

“…A comparison of the coccidian parasites in anadromous and landlocked fish demonstrated that the predominant coccidian in both forms of alewives was the same species, G. ameliae . This was supported by 100% sequence homology in the small subunit 18S ribosomal RNA gene, which has been demonstrated to be a useful gene for determination of taxonomy in apicomplexan parasites ( Morrison, 2008 ). The origin of the parasite in Lake Hopatcong cannot be verified since studies on coccidians of other freshwater species in the lake are lacking.…”

New malaria parasites of the subgenus Novyella in African rainforest birds, with remarks on their high prevalence, classification and diagnostics

“…It is important to note in this respect that a cladogram from a single molecular sequence (Fig. 5) represents only the phylogeny of that gene, which is not necessary the phylogeny of the species; this is a frequent oversight in apicomplexan parasites (Morrison 2008). For instance, the genus Plasmodium was viewed as paraphyletic relative to the genus Haemoproteus in a mitochondrial genome phylogeny (Perkins and Schall 2002), but was monophyletic in a recent three-genome phylogeny (Martinsen et al 2008).…”

Monophyly of marsupial intraerythrocytic apicomplexan parasites from South America and Australia

“…As discussed by Merino et al (2008) and Zhu et al (2009), a molecular identification of an enigmatic parasite named Elleipsisoma thomsoni from European moles could resolve the suspected relationship with our marsupial intraerythrocytic parasites. The field of molecular phylogenetics has a major impact on the recent improved nomenclature of apicomplexan parasites (Morrison, 2008). For example, it has provided the critical evidence for the distinct origin of avian Isospora species from Cystoisospora species, linked Atoxoplasma species with avian Isospora species, supported the position of Lankesterella and Caryospora species within eimerid coccidia and has been used to link yet unknown intranuclear parasites within coccidia (Carreno and Barta, 1999; Merino et al 2006; Innis et al 2007; Schmidt et al 2008).…”