Piscicolidae
From Wikipedia, the free encyclopedia
| Piscicolidae | |
|---|---|
 | |
| Piscicola geometra on a trout (Salmo trutta fario) | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Clade: | Pleistoannelida |
| Clade: | Sedentaria |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Infraclass: | Euhirudinea |
| Order: | Rhynchobdellida |
| Family: | Piscicolidae Johnston, 1865[1][2] |
| Subfamilies | |
| |
The Piscicolidae are a family of jawless leeches in the order Rhynchobdellida that are parasitic on fish. They occur in both freshwater and seawater, have cylindrical bodies, and typically have a large, bell-shaped, anterior sucker with which they cling to their host.[3] Some of the leeches in this family have external gills, outgrowths of the body wall projecting laterally, the only group of leeches to exchange gases in this way.[3]
Worldwide, around 60 genera and 100 species of leeches are in this family, all parasitic on the blood of marine, estuarine, and freshwater fishes. These leeches are less common in the tropics, and more abundant in temperate and polar waters.[4]
Historically, the Piscicolidae have been divided into three subfamilies: the Pontobdellinae, characterised by two pairs of pulsatile vesicles on each urosome segment; the Piscicolinae, characterised by a single pair of pulsatile vesicles on each urosome segment; and the Platybdellinae, with no pulsatile vesicles.[4] However, molecular phylogenetic analyses performed by Williams and Burreson in 2006, do not support these subdivisions. The Piscicolidae were confirmed as being monophyletic, but the Platybdellinae were shown to be polyphyletic with four distinct clades, and the Piscicolinae were similarly polyphyletic, again with four distinct clades, and the Pontobdellinae were paraphyletic with respect to the genus Oxytonostoma.[5]
