Coevolution of the Monogenoidea (Platyhelminthes) based on a revised hypothesis of parasite phylogeny

A preliminary phylogenetic analysis of the Capsalidae (Platyhelminthes: Monogenea: Monopisthocotylea) inferred from large subunit rDNA sequences

“…Therefore, our hypothesis implies that capsalid species from elasmobranchs evolved relatively recently from capsaline relatives infecting teleosts. This supports the views on coevolution by Boeger & Kritsky (1997) who proposed that capsalids evolved and radiated on neopterygiians and secondarily dispersed to sturgeons, sharks and rays.…”

The Capsalidae (Monogenea: Monopisthocotylea): a review of diversity, classification and phylogeny with a note about species complexes

“…This preliminary phylogeny, therefore, appears to support the coevolutionary hypothesis proposed by Boeger and Kritsky (1997) and suggests that entobdellines may represent a relatively recent capsalid radiation derived from capsalines (or capsaline-like ancestors) on teleosts. If my new conception of the Entobdellinae (see above) is correct, the fact that most described and newly discovered entobdellines infect batoids implies that teleosts may be a newly acquired host group for this subfamily.…”

“…Although most capsalids infect teleosts, the fact that family members parasitize ancient (sharks, rays and sturgeons) and modern (teleost) fishes demands that a complete knowledge and understanding of capsalids is critical for a full comprehension of long-standing questions about early evolution and radiation of Monogenea across fishes. Boeger and Kritsky (1997) proposed that capsalids coevolved with their principally modern fish hosts and dispersed secondarily, by host-switching, to older lineages, but until recently no phylogenetic hypothesis for the Capsalidae has been available to test this suggestion (see below). Entobdella is exclusive because six species infect ray skin and three species parasitize the skin of some flatfish teleost species , but E. hippoglossi has been recorded from a roundbodied teleost species (Egorova 2000a, Table 1).…”

Systematics of the Eucestoda: advances toward a new phylogenetic paradigm, and observations on the early diversification of tapeworms and vertebrates

“…Brooks (1989) suggested that initial diversification of digeneans, monogeneans and cestodarians coincided with the origins and divergence of lineages for chondrichthians and Osteichthyes. Boeger & Kritsky (1997) have postulated that there was a radiation of monogeneans in early chondrichthians that largely went extinct and that extant groups of parasites in neoselachians represent a colonisation from teleosts. In the case of the Digenea, their sister group, the aspidogastreans, is also relictual, with basal members in chondrichthians and occasionally other aquatic hosts.…”