Molecular phylogeny of pontobdelline leeches and their place in the descent of fish leeches (Hirudinea, Piscicolidae)

Abstract

Molecular phylogeny of pontobdelline leeches and their place in the descent of fish leeches (Hirudinea, Piscicolidae). -Zoologica Scripta, 36 , 271-280.Phylogenetic relationships of all genera of the fish leech subfamily Pontobdellinae were investigated using mitochondrial (12S rDNA, COI, tRNA-Leu, ND1) and nuclear (28S rDNA) DNA sequences under maximum likelihood, Bayesian inference and parsimony. All methods resulted in trees that corroborated the monophyly of the family Piscicolidae, but recovered their subfamily Pontobdellinae as non-monophyletic. Based on the basal position of the giant Antarctic Megaliobdella szidati , it is hypothesized that the putative ancestor of fish leeches was a free-ranging, large bodied, muscular leech. The next branch contains parasites of cartilaginous fishes, Pontobdella muricata and Pontobdella macrothela . Two remaining genera of the subfamily (the Arctic Oxytonostoma and the Antarctic Moorebdellina ) showed weak affinities to other piscicolid taxa. The obtained phylogenetic hypothesis suggests a possible transition from an ancestral free-ranging life style and temporary parasitism, to parasitism on cartilaginous fishes, followed by parasitism on bony fishes.

New tentacled leech Ceratobdella quadricornuta n. g., n. sp. (Hirudinida: Piscicolidae) parasitic on the starry skate Raja georgiana Norman from the Scotia Sea, Antarctica

“…Phylogenetic analyses demonstrated that both the tribe Platybdellini and the subfamily Platybdellinae (piscicolid leeches with no pulsatile vesicles) are not monophyletic groups (Williams & Burreson 2006;Utevsky et al, 2007). Admittedly, the information on the reproductive system and other internal organs seems not to be enough to determine phylogenetic affinities of Ceratobdella.…”

“…The tribe Platybdellini includes seven genera: Platybdella Malm, 1863, Cryobdella Harding, 1922, Heptacyclus Vasilyev, 1939, Malmiana Strand, 1942, Oceanobdella Caballero, 1956, Sanguinotus de Silva & Burdon-Jones, 1961and Arctobdella de Silva & Kabata, 1961 Malmiana is now considered a junior synonym of Heptacyclus (see Williams & Burreson, 2006). The boreal genera Platybdella, Heptacyclus and Oceanobdella possess a number of morphological, biogeographical and phylogenetic affinities (Utevsky, 2003;Utevsky & Trontelj, 2004;Williams & Burreson, 2006;Utevsky et al 2007). In contrast to Ceratobdella, species of Heptacyclus and Oceanobdella have eyes and usually these leeches are wellpigmented or have a colouration pattern on the body.…”

A new marine fish leech species of the genus Oceanobdella (Clitellata, Piscicolidae) from coastal waters of Sakhalin Island

“…This species has been already employed in several molecular phylogenetic analyses under the name of Oceanobdella sp. (Utevsky and Trontelj 2004, Williams and Burreson 2006, Utevsky et al 2007) and its morphological description is presented herein.…”

New information on the geographical distribution of Piscicola brylinskae Bielecki, 2001 (Hirudinea: Piscicolidae) in Poland and remarks on its systematic position

“…What is more, the new molecular studies have raised doubts on the monophyly of the Platybdellinae and Piscicolinae, and implied that Pontobdellinae could be paraphyletic (Williams & Burreson 2006). Recently, the Pontobdellinae have been described also as polyphyletic (Utevsky et al 2007).…”

“…The existing division to 18 tribes and 52 genera Epshtein 2004) in the latest morphological and molecular studies have been examined (Siddall et al 2001;Utevsky & Trontelj 2004). Moreover, some of the latest molecular studies questioned the previous division of Piscicolidae into 18 tribes (Utevsky et al 2007;Williams & Burreson 2006). What is more, the new molecular studies have raised doubts on the monophyly of the Platybdellinae and Piscicolinae, and implied that Pontobdellinae could be paraphyletic (Williams & Burreson 2006).…”