Semiscolecidae

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Semiscolecidae
Systematics
Class : Belt worms (Clitellata)
Subclass : Leeches (Hirudinea)
Subclass : Bristle flukes (Euhirudinea)
Order : Trunkless leeches (Arhynchobdellida)
Subordination : Pine rule (Hirudiniformes)
Family : Semiscolecidae
Scientific name
Semiscolecidae
Scriban & Autrum , 1934

Semiscolecidae is the name of a family of predatory and amphibious living leeches in the order of Kieferegel which only rudimentary or have no jaw. They are common in South America .

features

The large leeches of the Semiscolecidae family , outwardly reminiscent of roller gels , have 5 pairs of eyes in the head region that are arranged in an arc. They only have rudimentary, toothless three or even only one central dorsal or no jaw in their mouth. The throat has 3 to 12 strips and is similar to that of the horse leech . In adaptation to the predatory way of life, the intestinal canal has only small or no blind sacs at all. 15 to 17 segments are provided with five ringlets on the outside. There are 2 ½ to 7 ringlets between the genital pores. The genital organs of the hermaphrodite animals with their well-developed penis have the typical structure of the jaw rule : the leeches have small round ovaries , short paired fallopian tubes , a long common fallopian tube and a tubular or spindle-shaped vagina . The male genitalia consist of a long atrium that extends into the 15th segment and an epididymis of variable size , whereby ejaculatory bulbs can also be present. There are one or two pairs of testicles in each of the testicle-bearing segments .

Distribution, habitat and way of life

The flukes of the Semiscolecidae family live amphibiously - both in freshwater and on land - in South America and Central America and feed on small animals in a predatory manner. The prey is swallowed whole. For leeches of the genus Semiscolex , earthworms are a main prey.

Life cycle

Like other leeches , the Semiscolecidae are hermaphrodites . As a rule of the jaw , they have penises with which they mate each other. The eggs are placed in egg cocoons from which fully developed leeches hatch.

Systematics

The Swedish naturalist Johan GH Kinberg gave the South American leeches he described in 1866 the generic name Semiscolex "half worm" ( ancient Greek ἥμισυς hḗmisys "half" and σκώληξ skṓlēx "worm"), describing the species Semiscolex juvenilis ("juvenile half worm"). The Semiscolecidae family was established by the German zoologists IA Scriban and H. Autrum in 1934.

Genera

According to the current definition of the family, according to Raúl Adolfo Ringuelet from 1972, the Semiscolecidae family comprises two genera: The 3 species of leeches of the genus Semiscolex Kinberg , 1866 live in South America in the area of ​​the Río de la Plata in Uruguay , Argentina and Paraguay , but also as far as Bolivia and ins northeastern Brazil . The 3 species of the genus Patagoniobdella Ringuelet , 1972 ("Patagonian flukes"), which until then were included in Semiscolex , are native to Patagonia in the Andes of Argentina and Chile .

The genera previously included in the family Semiscolecidae Cyclobdella Weyenbergh 1879 ( "Circle Egel" from the Greek κύκλος kyklos , βδέλλα bdélla ; not to be confused with the similarly written genus Cylicobdella pit 1871 in the family Cylicobdellidae after κύλιξ ) and Orchibdella Ringuelet 1945 ("Testicle flukes " from Greek ὄρχις órchis , βδέλλα bdélla ) were placed by Ringuelet in 1972 in the new family Cyclobdellidae .

species

According to Sawyer (1986), the genus Semiscolex has 3 species:

The genus Patagoniobdella also includes 3 species:

Phylogenetically related genera

On the basis of their molecular genetic investigations, Anna J. Phillips and Mark E. Siddall proposed in 2009 that the following genera of leeches , which had previously been part of the family Hirudinidae sl, should be added to an extended family Semiscolecidae sl:

The result of the work of Phillips, Siddall and others (2010) is, however, next to the family Semiscolecidae s. str., ie in their previous smaller scale, as the closest related groups families Macrobdellidae (with the genera Macrobdella , Philobdella and Oxyptychus ) and Praobdellidae (with the genera Praobdella , Myxobdella , Dinobdella , Pintobdella , Limnobdella , Limnatis and the new genus Tyrannobdella to) put.

literature

  • Johan GH Kinberg: Annulata nova. Öfversigt Af Kongelige Vetenskaps-Akademiens Förhandlingar, Stockholm 1866. Semiscolex juvenilis Kinberg, 1866.
  • IA Scriban, H. Autrum: Hirudinea. In: Willy Georg Kükenthal, Thilo Krumbach (ed.): Handbuch der Zoologie II, Volume 2, No. 8. Walter de Gruyter, Berlin 1928–1934. P. 119.
  • Raúl Adolfo Ringuelet (1972): Nuevos taxia de hirudíneos neotrópicos con la redefinición de Semiscolecidae y la descripción de Cyclobdellidae fam. nov. y Mesobdellidae fam. nov. Physis (Rio de Janeiro, Brasil) 31, pp. 193-201.
  • P. Parker Sybil: Synopsis and Classification of Living Organisms, Volume 2. McGraw-Hill Book Company, 1982. Semiscolecidae, p. 50.
  • Roy T. Sawyer: Leech Biology and Behavior: Feeding biology, ecology, and systematics. Clarendon Press, Oxford 1986. pp. 681, 792-793.
  • 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).
  • Anna J. Phillips, Renzo Arauco-Brown, Alejandro Oceguera-Figueroa, Gloria P. Gomez, María Beltrán, Yi-Te Lai, Mark E. Siddall (2010): Tyrannobdella rex n. Gen. N. Sp. and the evolutionary origins of mucosal leech infestations. PLoS One 5 (4), e10057. doi : 10.1371 / journal.pone.0010057 .

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