Ingolfiellidea

Ingolfiella ischitana

Ingolfiellidea are a small suborder of amphipods with a total of 39 described species. However, since they live in poorly known ecological niches, numerous new taxa are to be expected. At present, the suborder is divided into the two families Ingolfiellidae and Metaingolfiellidae, the latter is monotypic and includes only the type Metaingolfiella mirabilis.

Features

The Ingofiellidea is a derived group is easily distinguished from the other groups of amphipods due to their morphological features. The distinction within the suborder is difficult and often takes place on the basis of studies with the scanning electron microscope. The Ingolfiellidae are usually very small amphipods with a length of a few millimeters. Some cave- dwelling species can be up to 2.5 cm long. They have short tergites what their body gives a worm- like appearance.

Habitats and distribution

The first two species descriptions of Ingofielliden, which were carried out by Hansen in 1903, involved two types of very 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 Abyssal. Ingolfiella abyssi belongs to the biocenosis of the deep-sea benthos, is known about its composition because of the inaccessibility of the habitat little. The second type was described Ingolfiella littoralis from the interstitial system ( Mesopsammon ) to the beaches of Thailand. This habitat is also little studied, the animals that live here are very small. Ingolfiella littoralis is particularly adapted thanks to its elongated shape and the special training of their pairs of legs in this ecological system.

The third Ingolfielliden - species was described in 1933 by S. Karaman. It is Ingolfiella acherontis, which was found in a groundwater- fed fountain in Skopje, Macedonia. Karaman did not know the two already described Ingolfiella species or he expected to find a similar style in fresh water. He therefore ordered the way for the time being as to Balcanella acherontis creating a family of amphipods.

Another type was found in a cave in the Congo and described in 1951. It was much greater than that only up to 2.5 mm with 14.5 mm types described so far. Later, she was placed in a separate genus Trogloleleupia and now called Trogloleleupia leleupi.

So were the four main habitats where Ingolfiellidea can happen delineated: deep sea, sand gap systems, groundwater and cave lakes. There were, however, with each newly discovered species further variants of these extreme habitats, including the sandy shore of a river course in the Andes ( Ingolfiella uspallatae ) or brackish groundwater near the coast ( Ingolfiella ruffoi and Ingolfiella manni ).

The Ingolfiellidea are found worldwide, their discovery areas, however, appear to be very small and widely scattered. Therefore, most species are considered endangered.

Phylogeny and systematics

It is believed that the Ingolfiellidea have split off the latest in the triad of the other amphipods. This conclusion is obvious since the distribution areas of the individual Ingolfiella species are very far apart. This distribution pattern can be created only by the continental drift after the disintegration of the supercontinent Pangaea.

There have been various approaches to subdivide the genus Ingolfiella which currently includes most of the species into several subgenera. A final classification is currently not useful, because too few species are known to allow a clear assignment to phylogenetically well-defined groups.

The type Metaingolfiella mirabilis, for my own family has been set up, it is a relic form, which was found in a 50 m deep well in central Italy. The nature of the ground is likely that a long time has not come into contact with the surface, survived.