Ovoviviparia
As ovoviviparity also lecithotrophic Viviparie ( Latin ; literally "egg-live-birth", therefore also called as eilebendgebärend), refers to a special form of reproduction , both features of oviparity as the Viviparie has. The yolk-rich eggs of ovoviviparous animals are not deposited, but hatched in the womb, nourished by yolk . The young hatch in the body of the mother or shortly after the oviposition. The transition between oviparity and ovoviviparity is partly fluid.
Differentiation from viviparia
Ovoviviparity is sometimes also referred to as aplacental viviparity , but this is incorrect, since in viviparity there are other aplacental feeding forms for the embryo in addition to placental nutrition. The term yolk sac viviparia is more appropriate .
Viviparous animals are born , oviparous hatch from an egg. The main difference between live births ovoviviparen animals and viviparous animals is that the embryo only by the information contained in the egg yolk (yolk sac) at ovoviviparen animals its nutrients independently from the metabolism gets the dam and the vivipare embryo from the organism is nourished of the dam.
Distribution in the animal kingdom
Ovoviviparous animals are relatively common in certain animal groups. However, ovoviviparia is often not exactly differentiated from viviparity. The following animals or groups of animals are often referred to as ovoviviparous:
- many cartilaginous fish , in addition to an even larger number of oviparous or viviparous species
- some bony fish , for example representatives of the toothed fish , which are very popular in the aquarium hobby (with the guppy , the swordtail , the black molly and the platy );
all forms of viviparity are also represented here - many reptiles , such as the garter snakes , almost all sea snakes , around 20 percent of the chameleons , as well as the native slow worm , the forest lizard , the European horned viper and the adder ;
There are also viviparous representatives among the reptiles (some skinks and certain snakes ) - Among the invertebrates there are some representatives of the spiders , the aphids and various groups of snails such as snails and door snails
Transitional forms
In addition to the possibility of going through the entire embryonic development in the mother's body, there are also intermediate forms in which a distinction is made according to the stage of development of the animals born:
- Larviparie: Larviparie are, for example, the fire salamander , which releases its larvae into the water, but also some leaf beetles ( Chrysomela ) and individual mayflies , such as Cloeon dipterum .
- Pupiparie: Pupiparie are those insects whose larvae pupate immediately after birth , such as louse flies (Hippoboscidae) and tsetse flies ( Glossina ).
Discussion of terms
Since the term ovoviviparic is based on viviparial and thus suggests that it is a form of live birth, there is a suggestion to change the term to vivioviparic (also vivi -oviparial). The reason given is that it is a real oviparity (i.e. oviposition), in which the young animals only hatch immediately before or after oviposition.
literature
- Erwin Hentschel, Günther Wagner: Zoological dictionary. Animal names, general biological, anatomical, physiological terms and biographical data. 4th, revised and expanded edition. Gustav Fischer Verlag, Jena 1990, ISBN 3-334-00348-5 .
- Günter Masurat: Multiplication of chameleons. Basics, instructions, experiences. Herpeton, Offenbach 2005. ISBN 3-936180-06-7 .
- Adolf Remane , Volker Storch , Ulrich Welsch : Short textbook of zoology. 6th, revised edition. Gustav Fischer Verlag, Stuttgart et al. 1989, ISBN 3-334-00333-7 .
Individual evidence
- ↑ Wilfried Westheide, Gunde Rieger: Special Zoology. Part 2: Vertebrate or skull animals , 2nd edition, Spectrum, 2010, ISBN 978-3-8274-2039-8 , p. 389.
- ↑ Hans-Günter Petzold : Tasks and problems in researching the expressions of life of the lower amniotes (reptiles). In: Milu. Messages from the Tierpark Berlin-Friedrichsfelde. Vol. 5, Issue 4/5, 1982, ISSN 0076-8839 , pp. 485-786, (reprint: (= Berliner Tierpark-Buch. No. 38). Verlag für Biologie und Natur, Berlin 1984).