Bertolanius Nebulosus
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''Bertolanius'' is a genus of
tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them . In 1776, th ...
s belonging to the family
Eohypsibiidae ''Eohypsibiidae'' is a family of water bear or moss piglet, tardigrades in the class Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gained ...
. The species of this genus are found in Europe and Northern America. Species: * '' Bertolanius birnae'' * '' Bertolanius mahunkai'' * '' Bertolanius markevichi'' * '' Bertolanius nebulosus'' * '' Bertolanius portucalensis'' * '' Bertolanius smreczinskii'' * '' Bertolanius volubilis'' * '' Bertolanius weglarskae''


Overview


Background

''Bertolanius'' Özdikmen is one of three genera in the superfamily Eohypsibioidea, a super family of
tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them . In 1776, th ...
s belonging to the Eutardigrada class. As a genus, ''Bertolanius'' consist of 8 currently discovered species which can all be found in the northern parts of Europe and North America. All of the ''Bertolanius'' species have similar physical and morphological characteristics, with their main differences being in the structure of their eggs, claws, and buccal armature. The genus was originally named ''Amphibolus'' Bertolani but was renamed in 2008 to ''Bertolanius'' to avoid confusion with other similarly named genera and to pay homage to a major contributing researcher for many of the species in this genus, Roberto Bertolani.


General Superfamily Information


Distribution

Tardigrades are known to exist in almost every biome on the earth. There are terrestrial species, marine species, and even fresh water species have been found. The eight currently recognized species in the genus ''Bertolanius Özdikmen'' have a wide distribution ranging from colder arctic areas, including
Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...
and
Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
, to more temperate regions like the
Mediterranean The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...
. Terrestrial tardigrades can be found in damp environments on lichen and mosses and even on rock and soil samples. Marine species are found at all depths in all oceans across the world. Overall, tardigrades are one of the most widely distributed microscopic organisms.


Body Plan

Tardigrades belonging to the ''Bertolanius'' genus follow the same body plan as all other currently identified tardigrades, which consists of a head and four leg bearing segments for a total of five segments. The body plan of tardigrades is compact and is conserved across all species because of a loss of Hox genes in the early lineage of tardigrades. Tardigrades have three pairs of walking legs, one pair on each section, that are tipped with a paw-like structure. The ends of tardigrade legs have differences for each species, with some having more paw-like structures and some having structures that more resemble claws. The last pair of legs on the last segment of tardigrades is attached in a backwards orientation and can be extended above the animal for grasping onto its surroundings as well as anchoring the animal. Mature tardigrades are generally less than 1mm in length, with most species being around 0.5mm in length when fully grown. Tardigrades have translucent bodies and are usually colored with the pigments from their environments and by what they have eaten. Because of the similarities in the common layout of tardigrades, one of the main ways to distinguish between the different species is by examining their body plans. In particular, the ''Bertolanius'' tardigrades are mainly distinguished by the arrangement and type claw or paw attachments as well as by the differences in their eggs and buccal armatures.


Feeding

Tardigrades feed on plant and algae cells use their well defined buccal armature to suck the insides of the cell out. The arrangement of the buccal armature has similarities between both classes of tardigrades and generally consist of a buccal ring at the end of their face that is connected to a tubular pharynx and a sucking pharynx. These lead to an esophagus and later a stomach where digestion takes places. Both classes of tardigrades have a hardened extrusible stylet, or stylets, that they use to puncture plant and algae cells. tardigrades belonging to the
Eutardigrada Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendages. Primarily freshwater bound, some species have secondarily gained the ability to live in marine environments ('' Halobiotus''). By cryptobiosis many species are able ...
class generally have shorter stylets that do not cross in the mouth while Heterotardigrades have longer stylets that do cross. These differences are a contributing factor when identifying tardigrades.


Unique characteristics and adaptations

One unique characteristic of tardigrades is that they are eutelic organisms, meaning they have a set number of cells once the reach maturity, around 1000 cells for most species, though the number of cells in a mature individual can differ within a species. Development of mature eutelic organisms continues only in the growth of cells and not through cell division. The most fame worthy adaptation of tardigrades is their ability to withstand extreme conditions by entering cryptobiosis.
Cryptobiosis Cryptobiosis or anabiosis is a metabolic state in extremophilic organisms in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all measurable metabolic processes sto ...
is a state of reversible but extreme metabolic restriction that allows organisms to defend themselves against their surrounding environment. When environmental conditions are bad tardigrades curl up inside their cuticle and make new cuticle layers to protect themselves, this is called a tun. Once in cryptobiosis, tardigrades can survive incredible extremes in temperature, a complete lack of oxygen or water, extreme pressure and the vacuum of space, and radiation levels far above the lethal limit for humans. Tardigrades can stay in cryptobiosis for hours or days or even years depending on the conditions around them and are able to revive themselves within up to 24 hours after conditions have improved. However, tardigrades are not considered extremophiles as they do not live in these extreme conditions.


References

{{Taxonbar, from=Q22348096 Parachela (tardigrade) Tardigrade genera