Ingolfiellidea
| Ingolfiellidea | ||||||||||||
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Ingolfiella ischitana |
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| Scientific name | ||||||||||||
| Ingolfiellidea | ||||||||||||
| Hansen , 1903 |
Ingolfiellidea are a small suborder of the amphipods with a total of 39 described species. However, since they live in little-explored ecological niches , numerous new descriptions are to be expected. Currently, the subordination is divided into the two families Ingolfiellidae and Metaingolfiellidae , the latter is monotypical and includes only the species Metaingolfiella mirabilis .
features
The Ingofiellidea is a derived group that can be easily distinguished from the other groups of amphipods due to its morphological features. The differentiation within the subordination is more difficult and is often made on the basis of examinations with the scanning electron microscope . The Ingolfiellidae are mostly very small amphipods with a length of a few millimeters. Some cave-living species can also be up to 2.5 cm long. They have short tergites , which gives their bodies a worm-like appearance.
Habitats and distribution
The first two species descriptions of Ingofiellids, which were carried out by Hansen in 1903, concerned two species from completely different habitats. Ingolfiella abyssi comes from the deep sea , found in a sample from 3521 m depth in the North Atlantic near Greenland . This deep sea habitat is called the Abyssal . Ingolfiella abyssi belongs to the biocenosis of deep-sea benthos , about whose composition little is known due to the inaccessibility of the habitat. The second species described was Ingolfiella littoralis from the sand gap system ( mesopsammon ) of the beaches of Thailand . This habitat has also been little studied, the animals that live here are particularly small. Ingolfiella littoralis is particularly adapted to this ecological system due to its elongated shape and the special formation of its pairs of legs.
The third Ingolfiellid species was described by S. Karaman in 1933. It is Ingolfiella acherontis , which was found in a groundwater well in Skopje , Macedonia . Karaman did not know the two Ingolfiella species already described or did not expect to find a similar species in fresh water. Therefore, he initially assigned the species as Balcanella acherontis to its own family of amphipods .
Another species was found in a cave in the Congo and described in 1951. At 14.5 mm, it was considerably larger than the species described so far, only up to 2.5 mm in size. It was later placed in its own genus Trogloleleupia and is now called Trogloleleupia leleupi .
Thus the four essential habitats in which Ingolfiellidea can occur were delimited: deep sea, sand gap systems, groundwater and cave lakes. However, with each newly discovered species, further variants of these extreme habitats were found, including the sandy banks of a river in the Andes ( Ingolfiella uspallatae ) or brackish groundwater near the coast ( Ingolfiella ruffoi and Ingolfiella manni ).
The Ingolfiellidea are widespread worldwide, but their find areas seem to be very small and widely scattered. Therefore, most of the species are considered endangered.
Tribal history
It is assumed that the Ingolfiellidea split off from the other amphipods at the latest in the Triassic . This conclusion is obvious, since the distribution areas of the individual Ingolfiella species are very far apart. This distribution pattern can only have been caused by the continental drift after the collapse of the supercontinent Pangea .
There have been various approaches to subdivide the genus Ingolfiella , which currently includes most species, into several sub-genera. However, a final classification is currently not meaningful, as too few species are known to allow a clear allocation to phylogenetically clearly delimited groups.
The species Metaingolfiella mirabilis , for which a separate family was established, is a relic form that was found in a 50 m deep well in central Italy. The species likely survived in groundwater that has not come into contact with the surface for a long time.
Systematics and taxonomy
The type species Ingolfiella abyssi was discovered during the Danish expedition with the research vessel Ingolf in the years 1895 to 1896 near the Davis Strait , a strait between the Canadian Baffin Island and Greenland . This way the family Ingolfiellidae were in 1903 because of its exceptional features in addition to the reports published in Copenhagen Expedition reports of Hans Jacob Hansen in the Journal of the Linnean Society of London first described .
Genera
Family Ingolfiellidae
- Ingolfiella Hansen, 1903
- Proleleupia Vonk & Schram, 2003
- Rapaleleupia Vonk & Schram, 2007
- Stygobarnardia Ruffo, 1985
- Trogloleleupia Ruffo, 1974
Metaingolfiellidae family
- Metaingolfiella Ruffo, 1969
Individual evidence
- ^ HJ Hansen: The Ingolfiellidae, fam. n., a new type of Amphipoda. Journal of The Linnean Society of London, Zoology, 29, pp. 117-133, 1903 doi : 10.1111 / j.1096-3642.1903.tb00430.x
literature
- Hans Jacob Hansen : The Ingolfiellidae, fam. n., a new type of Amphipoda. Journal of The Linnean Society of London, Zoology, 29, pp. 117-133, 1903 doi : 10.1111 / j.1096-3642.1903.tb00430.x (first description)
- Ronald Vonk and Frederick R. Schram: Ingolfiellidea (Crustacea, Malacostraca, Amphipoda): a phylogenetic and biogeographic analysis . Contributions to Zoology, 72, 1, 2003
Web links
- The subordination Ingolfiellidea . In: Fauna Europaea Database. European Commission under the Fifth Framework Program, accessed on February 27, 2010 .