| Diuronotus aspetos | |
|---|---|
 | |
| Diuronotus aspetos | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Gastrotricha |
| Order: | Chaetonotida |
| Family: | Muselliferidae |
| Genus: | Diuronotus |
| Species: | D. aspetos |
| Binomial name | |
| Diuronotus aspetos Todaro, Balsamo & Kristensen, 2005 [1] | |
Diuronotus aspetos is a species of large sized meiofaunal chaetonotid gastrotrich [1] [2] found in the North Atlantic. [3] With Diuronotus rupperti , it is one of the only two species representing the genus Diuronotus . [4]
Diuronotus aspetos has originally been considered as a "High Arctic species" found in low Arctic only in winter since it has originally been found in its type locality (Kigdlugssaitsut, Disko Island, West Greenland) exclusively during winter. [1] However, in 2006, the animal has also been sampled during the summer in the bay of Iterdla (also in Disko Island). [5] Specimens are found in 2 to 5 meters water depth in well-sorted sand with detritus. D. aspetos appears to be associated to a rich diversity of Gastrotricha like Chaetonotus atrox , Halichaetonotus sp., Mesodasys sp., Paradasys sp., Tetranchyroderma sp., Thaumastoderma sp. and Turbanella sp. [5] The range of the species was greatly extend in 2012 through discovery of an adolescent specimen from sandy bottom at a depth of 15.5 meters near Wangerooge in the North Sea. This represents a much warmer environment than previously recorded for the species. [3]
Diuronotus aspetos is one of the largest chaetonotid gastrotrich with more than 500 μm length. The pharynx is approximately one third of the body length. The mouth forms a muzzle surrounded by a ciliary band connecting the ventral ciliated field. There are no eye spots but there are four to six cephalic cilia. The adults are simultaneous hermaphrodites. [1]
Each of the two cauda forms distally a furca. The second furca of each caudum arises ventrally and bears also an adhesive duo-gland system. These secondary tubes of the furca are one of the most important diagnostic character of the genus Diuronotus. Each of the furca bears scales. [1] [5]
There is between 40 and 50 cuticular alternating columns enveloping the body, each about approximately 50 scales each. They are relatively elongated and overlap antero-laterally. Each of the scale has a median keel. The interciliary ventral field also bears scales similar to the dorsal ones. [1]
Apart from the sensory and head cilia mentioned above, the ventral ciliation is continuous and dense, extending from the posterior edge of the mouth to the two-thirds of the pharynx. Then, the ciliary field separates in two bands running until the posterior part of the body. The very anterior part of the ciliary continuous dorsal field is wider than the more posterior part. [1]
With Diuronotus rupperti, the genus Diuronotus contains only two species originally included in the subfamily Chaetonotinae Kisielewski, 1991. However, a systematic relationship have been proposed between Diuronotus and the genus Musellifer , [1] justifying the erection of a new family for this two genera: Muselliferidae. [6] The characters justifying this relationship are a muzzle like ciliated structure surrounding the mouth and the homogeneous ultrastructure of the scales. Some characters of the spermatozoids like the presence of supernumerary membranes also justify a close relationship between Diuronotus and Musellifer. [5]
The gastrotrichs, commonly referred to as hairybellies or hairybacks, are a group of microscopic (0.06-3.0 mm), worm-like, acoelomate animals, and are widely distributed and abundant in freshwater and marine environments. They are mostly benthic and live within the periphyton, the layer of tiny organisms and detritus that is found on the seabed and the beds of other water bodies. The majority live on and between particles of sediment or on other submerged surfaces, but a few species are terrestrial and live on land in the film of water surrounding grains of soil. Gastrotrichs are divided into two orders, the Macrodasyida which are marine, and the Chaetonotida, some of which are marine and some freshwater. Nearly 800 species of gastrotrich have been described.
Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956.
Paramecium is a genus of eukaryotic, unicellular ciliates, commonly studied as a representative of the ciliate group. Paramecia are widespread in freshwater, brackish, and marine environments and are often very abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, it has been widely used in classrooms and laboratories to study biological processes. Its usefulness as a model organism has caused one ciliate researcher to characterize it as the "white rat" of the phylum Ciliophora.
The Colpodea are a class of ciliates, of about 200 species common in freshwater and soil habitats. The body cilia are typically uniform, and are supported by dikinetids of characteristic structure, with cilia on both kinetosomes. The mouth may be apical or ventral, with more or less prominent associated polykinetids. Many are asymmetrical, the cells twisting sideways and then untwisting again prior to division, which often takes place within cysts. Colpoda, a kidney-shaped ciliate common in organic rich conditions, is representative.
The hypotrichs are a group of ciliated protozoa, common in fresh water, salt water, soil and moss. Hypotrichs possess compound ciliary organelles called "cirri," which are made up of thick tufts of cilia, sparsely distributed on the ventral surface of the cell. The multiple fused cilia which form a cirrus function together as a unit, enabling the organism to crawl along solid substrates such as submerged debris or sediments. Hypotrichs typically possess a large oral aperture, bordered on one side by a wreath or collar of membranelles, forming an "adoral zone of membranelles," or AZM.
Disko Island is a large island in Baffin Bay, off the west coast of Greenland. It has an area of 8,578 km2 (3,312 sq mi), making it the second largest of Greenland after the main island and one of the 100 largest islands in the world.
Limnognathia maerski is a microscopic freshwater animal, discovered living in warm springs on Disko Island, Greenland, in 1994. Since then, it was also found in Crozet Islands of Antarctica.).
The Aspidogastrea is a small group of flukes comprising about 80 species. It is a subclass of the trematoda, and sister group to the Digenea. Species range in length from approximately one millimeter to several centimeters. They are parasites of freshwater and marine molluscs and vertebrates. Maturation may occur in the mollusc or vertebrate host. None of the species has any economic importance, but the group is of very great interest to biologists because it has several characters which appear to be archaic.
Stylonychia is a genus of ciliates, in the subclass Hypotrichia. Species of Stylonychia are very common in fresh water and soil, and may be found on filamentous algae, surface films, and among particles of sediment. Like other Hypotrichs, St ylonychia has cilia grouped into membranelles alongside the mouth and cirri over the body. It is distinguished partly by long cirri at the posterior, usually a cluster of three. The largest can just be seen at a 25x magnification, and the smallest can just be seen at a 450x magnification.
The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the world, the main species for research being Saccoglossus kowalevskii. Two families—Harrimaniidae and Ptychoderidae—separated at least 370 million years ago.
Macrodasyida is an order of gastrotrichs. Members of this order are somewhat worm-like in form, and not more than 1 to 1.5 mm in length.
The Chaetonotida is an order of gastrotrichs. They generally have a tenpin or bottle-like shape.
Euplotes is a genus of ciliates in the subclass Euplotia. Species are widely distributed in marine and freshwater environments, as well as soil and moss. Most members of the genus are free-living, but two species have been recorded as commensal organisms in the digestive tracts of sea urchins.
Pseudunela cornuta is a species of minute sea slug, an acochlidian, a shell-less marine and temporarily brackish gastropod mollusk in the family Pseudunelidae. Adults are about 3 mm long and live in the spaces between sand grains.
Rhabdopleura normani is a small, marine species of worm-shaped animal known as a pterobranch. It is a sessile suspension feeder, lives in clear water, and secretes tubes on the ocean floor.
Thaumastoderma heideri belongs to the phylum Gastrotricha and the order Macrodasyida, which are worm shaped, mainly marine species of meiofauna. They live in coarser sand and like the rest of the gastrotrichs their movement is very slow. The family Thaumastodermatidae includes more than 130 species and it can be found widely across the globe.
Lepidodermella squamata is a freshwater species of minute worm in the phylum Gastrotricha.
Pseudoceros canadensis is a species of free-living, flatworm in the genus Pseudoceros, belonging to the family Pseudocerotidae.
Halteria, sometimes referred to as the jumping oligotrich, is a genus of common planktonic ciliates that are found in many freshwater environments. Halteria are easy to locate due to their abundance and distinctive behaviour with observations of Halteria potentially dating back to the 17th century and the discovery of microorganisms. Over time more has been established about their morphology and behavior, which has led to many changes in terms of classification.
Diuronotus is a genus of gastrotrichs belonging to the family Muselliferidae.