Naididae
The Naididae (former synonym: Tubificidae, Vejdovsky, 1876) are a family of segmented worms ( Annelida ). They belong to the order of the Little Borster ( Oligochaeta ). It is quite different looking, about 1-100 mm long worms that occur both in the sea and in fresh water. Among them is the popular with aquarists Tubifex tubifex Fischnährtier.
Features
The mud tube worms have one hand on the general labeling the belt worms ( Clitellata ) and the Little Borster ( Oligochaeta ). In addition, they are characterized especially by characteristic bicuspid bristles.
Some species ( only within the Naidinae ) have secondarily developed simple eyes. Furthermore, isolated at the Tubificinae penis formations occur.
Biology and Ecology
The Naididae are like the Little Borster generally fundamentally hermaphrodite. The increase, therefore, is always performed via the normal two -sex reproduction. Addition, however, also comes asexual propagation by chain formation and division before (especially in the Naidinae ).
Some species are blood-red by hemoglobin, such as tubifex species. Some species have thereby and by other physiological adaptations, the possibility of a long time to survive under oxygen-free conditions. Some species are used for water quality assessment.
Marine species that live in oxygen-free sulfidic environments, often have no functioning intestine, but live in symbiosis with special chemoautotrophic bacteria (eg genus Inanidrilus ).
Genera that occur in the waters mud of rivers or still fresh waters, are, inter alia, Tubifex and Limnodrilus. A proliferation occurs only in waters whose sediments have a high percentage of usable organic material.
Occurrence
The Naididae come mainly in the marine area before, but in addition also often in fresh water.
System
The Naididae include about 800 species and are divided into several subfamilies that were previously partially out as a family or in part, still are. For example, the Naidinae were formerly their own family. After merging with the subfamilies of Tubificidae were then known as the entire family has been renamed due to the priority rule in Naididae. On the other hand, the following overall composition is also sometimes referred to as a family Tubificoidea. The molecular genetic research may in the future lead to even greater changes in the system.
- Dorydrilinae - only one genus, Dorydrilus Piguet in 1913, with 3 species.
- Lycodrilinae - only one genus, Lycodrilus pit in 1873, with several species.
- Naidinae - about 22 genera; transparent worms with a length of about 1-25 mm, (eg Chaetogaster and Pristina ).
- Parvidrilinae - only 1 recently described Type: Parvidrilus spelaeus Erséus 1999.
The following subfamilies appear to be more closely related to each other:
- Limnodriloidinae
- Phallodrilinae - 4 genera.
- Rhyacodrilinae - 9 genera, eg Branchiura.
- Telmatodrilinae - 1 species ( Alexandrovia ringulata Sokolskaja 1961).
- Tubificinae - at least 35 species. Genera Limnodrilus, Potamothrix, Tubifex tubifex, etc. For details, see below.
Molecular genetic studies have been slightly modified relationships to the outcome, but still can not provide a coherent overall picture.