| Crinolina isefiordensis | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Class: | Choanoflagellatea |
| Order: | Acanthoecida |
| Family: | Acanthoecidae |
| Genus: | Crinolina |
| Species: | C. isefiordensis |
| Binomial name | |
| Crinolina isefiordensis Thomsen, 1976 | |
Crinolina isefiordensis is a species of choanoflagellate in the family Acanthoecidae. It is the type species of the genus Crinolina [1] and is named for the first location of its collection, the Ise Fjord in Denmark.
Crinolina isefiordensis is a single-celled organism that lives in a skirt-shaped lorica (net-like structure) which is open on both ends. The protoplast of the type specimen measured 8 microns by 5 microns and it does not have a chloroplast. It has a flagellum between 2-3 times as long as the protoplasts which is ringed by a collar of tentacles inside the lorica. The lorica is even longer, up to 30 microns, and is twice as wide at the base as the neck. The lorica consists of around a dozen costae (filaments that create the exoskeleton) which are roughly straight and connect the costal rings at the base and neck. Each costa is made up of six or seven small strips that are joined. At the neck of the lorica, these costae end in spines that project outwards. [2]
The lorica of C. isefiordensis is highly similar in appearance to that of Diaphanoeca grandis in its structure. However, the main difference is that C. isefiordensis entirely lacks a membrane to connect the costae of the lorica, unlike D. grandis. Additionally, the flagellum of C. isefiordensis is usually seen curled up in a pig-tail shape, a characteristic unique to the species. [3]
There is some minor morphological variance across populations of C. isefiordensis. Most notably, warmer water populations tend to have fewer costae and less apparent spines. [3]
Crinolina isefiordensis is extremely similar to a Canadian arctic species of choanoflagellate, Diaphanoeca aperta. Because of their similarities, specifically the open rear end of their lorica, the latter species was moved into Crinolina creating the new combination Crinolina aperta . [2] Later phylogenetic analysis confirmed the close relationship of Crinolina and Diaphanoeca, but did not merge the genera and suggested that they may be sister to one another. [4]
The holotype of the species was collected in the winter in the cold waters of Ise Fjord in Denmark. The species has also been collected during the summer at Limfjord. [2] In 2007, C. isefiordensis was one of the first marine choanoflagellates to be identified off the coast of Chile, and the collected specimens were nearly identical to those from Denmark. [5] More recent studies have proven the species to be nearly cosmopolitan; it is not found only in low salinity areas like parts of the Baltic Sea as well as at extreme latitudes. [3]
The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. Choanoflagellates are collared flagellates, having a funnel shaped collar of interconnected microvilli at the base of a flagellum. Choanoflagellates are capable of both asexual and sexual reproduction. They have a distinctive cell morphology characterized by an ovoid or spherical cell body 3–10 µm in diameter with a single apical flagellum surrounded by a collar of 30–40 microvilli. Movement of the flagellum creates water currents that can propel free-swimming choanoflagellates through the water column and trap bacteria and detritus against the collar of microvilli, where these foodstuffs are engulfed. This feeding provides a critical link within the global carbon cycle, linking trophic levels. In addition to their critical ecological roles, choanoflagellates are of particular interest to evolutionary biologists studying the origins of multicellularity in animals. As the closest living relatives of animals, choanoflagellates serve as a useful model for reconstructions of the last unicellular ancestor of animals.
Amorphea is a taxonomic supergroup that includes the basal Amoebozoa and Obazoa. That latter contains the Opisthokonta, which includes the Fungi, Animals and the Choanomonada, or Choanoflagellates. The taxonomic affinities of the members of this clade were originally described and proposed by Thomas Cavalier-Smith in 2002.
Proterospongia is a genus of single-celled aquatic organisms which form colonies. It belongs to the choanoflagellate class. As a colony-forming choanoflagellate, Proterospongia is of interest to scientists studying the mechanisms of intercellular signaling and adhesion present before animals appeared.
Trachelomonas is a genus of swimming, free-living euglenoids characterized by the presence of a shell-like covering called a lorica. Details of lorica structure determine the classification of distinct species in the genus. The lorica can exist in spherical, elliptical, cylindrical, and pyriform (pear-shaped) forms. The lorica surface can be smooth, punctuate or striate and range from hyaline, to yellow, or brown. These colors are due to the accumulation of ferric hydroxide and manganic oxide deposited with the mucilage and minerals that comprise the lorica. In Trachelomonas, the presence of a lorica obscures cytoplasmic details of the underlying cell. In each Trachelomonas cell, there is a gap at the apex of the lorica from which the flagellum protrudes. Thickening around this gap results in a rim-like or collar-like appearance. During asexual reproduction, the nucleus divides yielding two daughter cells one of which exits through the opening in the lorica. This new cell then synthesizes its own new lorica.
Corallochytrium belongs to the class of Corallochytrea within Teretosporea and is a sister group to Ichthyosporea. Corallochytrium limacisporum is the only species of Corallochytrium known so far. It was first discovered and named in the Arabian Sea’s coral lagoons by Kaghu-Kumar in 1987. It was first thought to be a member of the fungi-like thraustochytrids, however, this was later disproven due to Corallochytriums lack of cilia and sagenogenetosome. Little research has been done on the life cycle or morphology. Most research concerning this genus has been done to uncover the evolution of animals and fungi, as Corallochytrium possess both animal and fungal enzymatic trademarks.
Trimastix is a genus of excavate protists, the sole occupant of the order Trimastigida. Trimastix are bacterivorous, free living and anaerobic. It was first observed in 1881 by William Kent. There are few known species, and the genus's role in the ecosystem is largely unknown. However, it is known that they generally live in marine environments within the tissues of decaying organisms to maintain an anoxic environment. Much interest in this group is related to its close association with other members of Preaxostyla. These organisms do not have classical mitochondria, and as such, much of the research involving these microbes is aimed at investigating the evolution of mitochondria.
Raphidiophrys is a genus of centrohelid with radiating axopodia. R. intermedia is found in the bottom sludge of freshwater bodies in Canada, Chile, Argentina, Australia, New Zealand, Malaysia, Russia, and central Europe. Raphidiophrys have bipartite scales are a defining characteristic among species. Differences in type and size of scales are used to differentiate amongst the members of this genus. The genus Raphidiophrys was discovered in 1867 by W. Archer. Raphidiophrys is one of very few centrohelids in which dimorphism has been shown.
Thaumatomastix is a protist genus of the order Thaumatomonadida, within the phylum Cercozoa and the class Imbricatea. Its species are aquatic, feeding on algae and appearing in waters of a wide range of temperatures and salinities, and are 15-50 micrometers long. They can interchange between flagellated and amoeboid forms, and are notable for being covered in both spiny and flattened siliceous scales.
Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.
Perkinsids are single-celled protists that live as intracellular parasites of a variety of other organisms. They are classified as the class Perkinsea within the monotypic phylum Perkinsozoa. It is part of the eukaryotic supergroup Alveolata, along with dinoflagellates, their closest relatives, and another parasitic group known as Apicomplexa. Perkinsids are found in aquatic environments, as parasites of dinoflagellates and various animals.
Parvilucifera is a genus of marine alveolates that behave as endoparasites of dinoflagellates. It was described in 1999 by biologists Fredrik Norén and Øjvind Moestrup, who identified the genus among collections of Dinophysis dinoflagellates off the coast of Sweden. Initially mistaken for products of sexual reproduction, the round bodies found within these collections were eventually recognized as sporangia, spherical structures that generate zoospores of a parasitic protist. This organism was later identified as P. infectans, the type species. The examination of this organism and its close genetic relationship to Perkinsus led to the creation of the Perkinsozoa phylum within the Alveolata group.
Neocercomonas is a protist genus of the order Cercomonadida. It consists of single-celled bacteriophagous organisms that usually live on or nearby terrestrial plants, both above and belowground. Species are biflagellate and may grow up to 60 micrometers long, with a trailing tail-like mass of protoplasm at their posterior end and a pair of roots connecting their posterior flagellum to the cytoskeleton.
Diaphanoeca grandis is a species of choanoflagellate in the family Acanthoecidae which is the type species of the genus Diaphanoeca. It is a unicellular micro-heterotroph with a large protective lorica that is found beneath sea ice in a wide distribution. The lorica is composed of silica and possibly originates from diatoms via Horizontal gene transfer.
Carlos José Correia de Azevedo is a Portuguese biologist specialising in microparasites of aquatic organisms, particularly Apicomplexa, Haplosporidia, Microsporidia, and Myxozoa.
Hyalochlorella marina, the only species in the genus Hyalochlorella and also known as Dermocystidium sp., is a marine heterotrophic eukaryote with uncertain phylogenic position.
Commation is a genus of marine heterotrophic protists closely related to the actinophryids. It contains two species, Commation cryoporinum and Commation eposianum, discovered in antarctic waters and described in 1993. Currently, the genus is classified within a monotypic family Commatiidae and order Commatiida. Along with the photosynthetic raphidophytes, these organisms compose the class of stramenopiles known as Raphidomonadea.
Commation cryoporinum is a species of heterotrophic protists discovered in 1993 in Antarctic waters. It is one of two species in the Commatiida, an order of stramenopiles closely related to actinophryids, a group of heliozoan protists, and to raphidophytes, a group of algae.
Urceolus is a genus of heterotrophic flagellates belonging to the Euglenozoa, a phylum of single-celled eukaryotes or protists. Described by Russian biologist Konstantin Mereschkowsky in 1877, its type species is Urceolus alenizini. Species of this genus are characterized by deformable sack-shaped cells that exhibit at least one flagellum that is active at the tip. They are found in a variety of water body sediments across the globe. Molecular phylogenies show they belong to a group known as peranemids, closely related to the euglenophyte algae.
An amoeboflagellate is any eukaryotic organism capable of behaving as an amoeba and as a flagellate at some point during their life cycle. Amoeboflagellates present both pseudopodia and at least one flagellum, often simultaneously.
Parviluciferaceae is a family of perkinsozoans, a group of endoparasitic protists present in aquatic environments.