Hirudinidae

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Hirudinidae
Medicinal leeches (Hirudo medicinalis) at a pond in northeastern Lower Saxony

Medicinal leeches ( Hirudo medicinalis ) at a pond in northeastern Lower Saxony

Systematics
Class : Belt worms (Clitellata)
Subclass : Leeches (Hirudinea)
Subclass : Bristle flukes (Euhirudinea)
Order : Trunkless leeches (Arhynchobdellida)
Subordination : Pine rule (Hirudiniformes)
Family : Hirudinidae
Scientific name
Hirudinidae
Whitman , 1886
Medicinal leech ( Hirudo medicinalis ) ingested by humans
Bite wound caused by Hirudo medicinalis , from which one can see the traces of the three jaws in the throat of the leech.

Hirudinidae is the name of a family of leeches in the subordination of Kieferegel with the freshwater living species known as ectoparasites at various vertebrates whose blood sucking. Since the revision of the family by Laurence R. Richardson in 1969, the family has been limited to species in Europe , Asia and Africa , which also applies to a possible new systematics according to Anna J. Phillips and Mark E. Siddall from 2009.

features

The leeches of the family Hirudinidae have large, cylindrical to dorsoventrally flattened bodies, of whose externally invisible segments 15 or 16 each include 5 outer ringlets. On the head there are 5 pairs of inconspicuous eyes that are arranged in a parabolic arc. The storage stomach (goiter) has 5 to 10 pairs of blind sacs, of which the two rearmost blind sacs (postcaeca) are elongated. The mouth takes up the entire interior of the front suction cup. The animals have a short, muscular throat with three large, powerful jaws, each of which is covered with a row (monostichodont) of more than 30 teeth.

As a hermaphrodite , the leeches have both male and female sexual organs. In medical leeches, the always well developed penis is an approximately 2 cm long, evenly thin, whitish thread that protrudes from the male genital opening in inserted specimens, while in horse leeches it is more compact, thickened distally and twisted like a corkscrew. The paired sperm conductor forms two loops to the front within the 11th segment, the epididymis being formed on the beginning previous and the middle retrograde, the ejaculatory bulb on the ending previous limb. The vagina has a blind sac and can have a vaginal tube.

The description here follows Laurence R. Richardson 1969 and is restricted to the blood-sucking Hirudinidae. When including the genera Haemopis (horse leech ) and Whitmania , leeches with the characteristics described under Haemopidae must be taken into account, including jaws with two rows of teeth (distichodont) or without teeth and an intestinal canal without blind sacs.

Distribution, habitat and example species

The flukes of the family Hirudinidae are common in freshwater of inland waters in Africa , Eurasia, and Australasia .

While the medicinal leech ( Hirudo medicinalis ) is widespread in Europe , North Africa and Asia Minor , the Mediterranean medicinal leech ( Hirudo verbana ) can be found in Turkey , southern Switzerland and Italy, among others .

Life cycle

The hermaphrodites mate with each other, attaching themselves to each other outside of the residential water with mucus from the clitellum and each partner inserting his penis into the vagina of the other partner. The penis is turned inside out at rest and is turned outwards by pressure from body fluid. A cocoon is deposited around the clitellum of each sex partner, in which about 10 eggs are laid. The cocoon is stripped off the front end of the mother's rule and placed in moist earth next to a body of water, and the eggs develop into small leeches, which go into the water after hatching.

nutrition

The Hirudinidae feed on the blood of various vertebrates . While mammals offer good opportunities for an extensive blood meal, amphibians and freshwater fish are usually more available. The leeches behave like predators towards small fish, amphibian larvae and also smaller adult frogs or newts , as the victim is completely sucked out or, in the case of smaller larvae, also swallowed.

Systematics

The family Hirudinidae was described by the American zoologist Charles Otis Whitman in 1886 with the type genus Hirudo Linnaeus , 1758 ( Latin hirudo " leech "). It initially comprised a large part of the blood-sucking leech species. Since then, the scope and thus the description of the characteristics of the family has been revised several times, including in 1969 by Laurence R. Richardson and most recently in 2009 by Anna J. Phillips and Mark E. Siddall , whereby the family now includes both blood-sucking and predatory species.

Genera

According to the most recent revision by Anna J. Phillips and Mark E. Siddall (2009), the family Hirudinidae includes the following genera :

Traditional subfamilies

According to the traditional systematics according to Roy T. Sawyer (1986), the Hirudinidae, a family in the subordination of the Hirudiniformes , comprise six subfamilies with the following genera:

Reorganization of the system in 2009 according to Phillips and Siddall

More recent molecular genetic studies in 2009 by Anna J. Phillips and Mark E. Siddall on leeches belonging to the blood-sucking Hirudinidae, the predatory Haemopidae , the terrestrial blood-sucking Haemadipsidae , the terrestrial predatory Xerobdellidae and the Central American predatory Semiscolecidae indicate that in the case of the traditional predatory Semiscolecidae Hirudinidae and Haemopidae as well as many of their sub-taxa are paraphyletic groups and the genera concerned can be classified into the following two larger monophyla.

Phillips and Siddall therefore add only a part of the genera originally listed here to a newly defined family Hirudinidae, but now the genera Haemopis ( horse leech ) and Whitmania , with which the family Haemopidae is dissolved:

Phillips and Siddall therefore initially proposed that several other genera, which were previously either part of the Hirudinidae or the Haemopidae, should now be combined in a new extended family Semiscolecidae (sensu lato) :

A clade forms from the Hirudinidae s. st. (new), the Xerobdellidae and the Haemadipsidae a sister group to the newly established family Semiscolecidae (sensu lato) .

The result of the work of Phillips, Siddall and others (2010) is, however, next to the family Semiscolecidae s. st. In their previous smaller extent, the families Macrobdellidae (with the genera Macrobdella , Philobdella and Oxyptychus ) and Praobdellidae (with the genera Praobdella , Myxobdella , Dinobdella , Pintobdella , Limnobdella , Limnatis and the new genus Tyrobdella ) are to be placed as closest related groups .

literature

  • Laurence R. Richardson (1969): A contribution to the systematics of the hirudinid leeches, with description of new families, genera and species. Acta Zoologica Hungarica 15 (1/2), pp. 97-149, here Hirudinidae (Whitman 1886, emended) s. str., p. 140 .
  • Roy T. Sawyer: Leech Biology and Behavior. Clarendon Press. Oxford 1986. Hirudinidae Whitman, 1886 , pp. 682-690.
  • Javier Oscoz, David Galicia, Rafael Miranda: Identification Guide of Freshwater Macroinvertebrates of Spain. Springer Science & Business Media, Dordrecht 2011. Hirudinidae , p. 56.
  • Hasko Nesemann, Eike Neubert: Annelida, Clitellata: Branchiobdellida, Acanthobdellea, Hirudinea. Spectrum Akademischer Verlag Heidelberg / Berlin 1999. p. 97.
  • Heinrich Georg Bronn: Dr. HG Bronn's Classes and Orders of the Thier-Reich: scientifically represented in words and pictures, Volume 2. CF Winter, Amsterdam 1939. P. 391.
  • Peter John Mill: Physiology of Annelids. Academic Press, London 1978, p. 340.
  • Urania Tierreich , Volume 2. Urania-Verlag, Leipzig / Jena / Berlin 1966. P. 81, Family Hirudinidae .
  • C. Wesenberg-Lund, O. Storch: Biology of freshwater animals - invertebrates. Published by Julius Springer, Vienna 1939. pp. 354–356.
  • Anna J. Phillips, Mark E. Siddall: Poly-paraphyly of Hirudinidae: many lineages of medicinal leeches. In: BMC Evolutionary Biology. Volume 9, October 2009, p. 246, doi : 10.1186 / 1471-2148-9-246 , PMID 19811660 , PMC 2768714 (free full text).

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