Propappus
| Propappus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the family | ||||||||||||
| Propappidae | ||||||||||||
| Coates , 1986 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Propappus | ||||||||||||
| Michaelsen , 1905 |
Propappus is the name of a genus in the sand in freshwater living oligochaetes , the only genus of mono generic family Propappidae in the annelid class of clitellata (Clitellata) whose three species in Eurasia are common.
features
The Propappidae are a few millimeters to a maximum of about 1.2 cm long and a maximum of 0.4 mm wide. They carry 4 bundles of s-shaped, nodular, forked bristles per segment (also on the genitals) - 3, rarely 2 bristles per bundle - and large glands in the epidermis directly behind each bristle bundle. There are no dorsal pores.
The brain is deeply divided into two lateral lobes. The intestinal canal has no blind sacs and in some cases expands abruptly at the beginning of the midgut. The anus is on the back. The large nephridia are well developed.
The ring-shaped clitellum of the hermaphrodite consists of a layer of cells comprising about 3 segments, mostly from the 12th to the 14th segment. The animals have a pair of testes in the 11th segment (on the septum to the 10th segment) and a pair of ovaries in the 13th segment (on the septum to the 12th segment). An unpaired sperm vesicle extends forward to the 6th segment. The paired Receptacula seminis open in front on the 4th segment to the outside and have no connection with the intestinal canal. The pair of male genital orifices is in the 12th segment in front of the ventral bundles of bristles, the only pair of female genital orifices in the furrow from the 13th to the 14th segment.
Distribution, habitat and way of life
The Propappidae are distributed as a Palearctic group in Eurasia and have been found in central and eastern Russia , Germany , Austria , England , France , Finland and Norway . They are freshwater inhabitants and can be found in the sand or gravel of lakes or rivers with moderate to strong currents, where they graze on microscopic algae and other microorganisms.
Systematics
In 1905 Wilhelm Michaelsen described the type species Propappus glandulosus at the same time as the genus Propappus on the basis of specimens collected in Lake Baikal in 1901 and placed them in the Enchytraeidae family . With reference to the bristles, he chose the name Propappus after the Greek word πρό “before” and πάππος “old man (with thinning hair or beard, like a pappus )”, while the Latin glandulosus “glandular” refers to the numerous bristle glands. On the basis of the special properties of the genus Propappus, such as the shape of the bristles and bristle glands , Kathryn A. Coates established the new monogeneric family Propappidae in 1986 and placed it close to both the Haplotaxidae and the Enchytraeidae.
Based on a molecular genetic work by Erséus and Källersjö from 2004, the Propappidae together with the Naididae (including the former Tubificidae ), Haplotaxidae and Phreodrilidae form a monophyletic taxon to which the Enchytraeidae do not belong.
The genus Propappus includes the following three species :
- Propappus glandulosus Michaelsen, 1905 (first found at Lake Baikal , 2 to 8 m depth)
- Propappus volki Michaelsen, 1916 (first found on the Elbe near Hamburg , 3 to 5 m depth)
- Propappus arhyncotus Sokolskaja, 1972 (first location Azabach'e Lake , Kamchatka , 7 cm depth)
literature
- Wilhelm Michaelsen : The Oligochetes of Lake Baikal. Scientific results of a zoological expedition to Lake Baikal under the direction of Professor Alexis Korotneff in the years 1900–1902. First delivery. R. Friedländer and Son, Berlin 1905. Propappus gen. Nov. , P. 24 and Propappus glandulosus sp. nov., p. 27.
- Kathryn A. Coates (1986): Redescription of the oligochaete genus Propappus and diagnosis of the new family Propappidae (Annelida, Oligochaeta). Proceedings of the Biological Society of Washington 99, pp. 417-428.
- Christer Erséus, Mari Källersjö (2004): 18S rDNA phylogeny of Clitellata (Annelida). Zoologica Scripta 33 (2), pp. 187-196.
- Barrie GM Jamieson, Marco Ferraguti: Non-leech Clitellata. In: Greg Rouse, Fredrik Pleijel (Eds.): Reproductive Biology and Phylogeny of Annelida. Science Publishers, Enfield (NH) 2006. Chapter 8, pp. 235-392. Propappidae p. 296.