Rhynchobdellida

Rhynchobdellida (from the Greek rhynchos, mouth, and bdellein, sucking),[1] the jawless leeches or freshwater leeches,[2] are an order of aquatic leeches.[3][4] Despite the common name "freshwater leeches", species are found in both sea and fresh water. They are defined by the presence of a protrusible proboscis instead of jaws, and having colourless blood.[5][6][7] They move by "inchworming"[8] and are found worldwide. The order contains 110 species, divided into 41 genera and three families.[8] Members of the order range widely in length, usually between 7 and 40 mm.[2] They are hermaphrodite.[2] The order is not monophyletic.[9]

Jawless leeches
Branchellion parkeri
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Annelida
Class: Clitellata
Subclass: Hirudinea
Infraclass: Euhirudinea
Order: Rhynchobdellida
Blanchard, 1893
Families

Appearance and eating habits
Glossiphoniidae: Smooth Turtle Leech (Placobdella parisitica) on a snapping turtle shell. (Southern United States)

Instead of jaws and teeth, Rhynchobdellidae have protrusible proboscises, which they use to penetrate the host's skin.[2][10] Mouths of Rhynchobdellidae species are small holes from which the proboscis can be protruded.[10] The proboscis then sucks out the desired bodily fluid from the host: usually blood or coelomic fluid in the case of invertebrate victims.[9]

Rhynchobdellidae are either sanguivorous or predatory. Sanguivorous species usually feed on a variety of other animals, using their proboscis to host's skin. They generate anticoagulants (like mosquitoes) and natural anaesthetia to help the feeding.[2] Predatory Rhynchobdellidae have digestive enzymes that help break down their prey, which usually consists of small invertebrates such as insect larvae or amphipods.[2]

Families

Glossiphoniidae (Freshwater jawless leeches)
Piscicolidae: Trachelobdella lubrica is a parasite of fish.

The Glossiphoniidae, the freshwater jawless leeches, or leaf leeches (due to their shape)[11] are freshwater leeches, flattened, and with a poorly defined anterior sucker.[2] The family Glossiphoniidae contains one of the world's largest species of leech, the giant Amazon leech, which can grow up to 45 cm in length.[12] Many species show extended parental care, keeping eggs in nests or pouches and caring for and feeding the young.[2][13] They feed on both vertebrate and invertebrate animals.[4]

Piscicolidae (Fish leeches)

The Piscicolidae occur in both freshwater and seawater, have cylindrical bodies, and a usually well-marked, bell-shaped, anterior sucker.[2][4] They are parasites of fish.[11][4] The family was originally divided into three subfamilies based on species' pulsatile vesicles, but the subfamilies were disbanded in 2006.[4]

Ozobranchidae: Ozobranchus jantseanus (dorsal view)

Ozobranchidae (Turtle leeches)

Ozobranchidae are primarily parasitic on marine turtles, and are sometimes merged with the Piscicolidae.[2][4]

See also

References
Wikispecies has information related to Rhynchobdellida.
  1. Mehlhorn, Heinz, ed. (2008), "Rhynchobdellida", Encyclopedia of Parasitology, Berlin, Heidelberg: Springer, p. 1249, doi:10.1007/978-3-540-48996-2_2723, ISBN 978-3-540-48996-2, retrieved 2022-11-27
  2. "Order Rhynchobdellida". keys.lucidcentral.org. Retrieved 2022-11-27.
  3. "Explore the Taxonomic Tree". FWS.gov. Retrieved 2022-11-27.
  4. Gulf of Mexico Origins, Waters, and Biota | Volume I: Biodiversity. Harte Research Institute. 2009. pp. 789–790. ISBN 9781603442695.
  5. "Rhynchobdellida | leech order | Britannica". www.britannica.com. Retrieved 2022-11-27.
  6. "Rhynchobdellida | Encyclopedia.com". www.encyclopedia.com. Retrieved 2022-11-27.
  7. "Definition of RHYNCHOBDELLIDA". www.merriam-webster.com. Retrieved 2022-11-27.
  8. "Rhynchobdellida - Encyclopedia of Life". eol.org. Retrieved 2022-11-27.
  9. Borda, Elizabeth; Sidall, Mark (2004-12-30). "Review of the evolution of life history strategies and phylogeny of the Hirudinida (Annelida: Oligochaeta)". Lauterbornia. 52: 7–15 – via ResearchGate.
  10. Rogers, D. Christopher; Thorp, James H. (2019-03-31). Thorp and Covich's Freshwater Invertebrates: Volume 4: Keys to Palaearctic Fauna. Academic Press. ISBN 978-0-12-385025-6.
  11. Thompson, Gerald; Coldrey, Jennifer; Bernard, George (1984). The pond. William Collins. pp. 116–118.
  12. "Amazon Giant Leech (Haementeria ghilianii) | Invertebrate Zoology". 2018-08-31. Archived from the original on 2018-08-31. Retrieved 2022-11-27.
  13. Rohde, Klaus (2005-09-13). Marine Parasitology. Csiro Publishing. ISBN 978-0-643-09927-2.
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