A chordate is a deuterostomic bilaterial animal belonging to the phylum Chordata. All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa. These five synapomorphies are a notochord, a hollow dorsal nerve cord, an endostyle or thyroid, pharyngeal slits, and a post-anal tail.
Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial arthropods such as fireflies. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves.
A tunicate is an exclusively marine invertebrate animal, a member of the subphylum Tunicata. This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the seriation of the gill slits. However, doliolids still display segmentation of the muscle bands.
The Notobranchaeidae, or "naked sea butterflies", are a taxonomic family of floating sea slugs, specifically under the subclass Opistobranchia, also called "sea angels".
Larvaceans or appendicularians, class Appendicularia, are solitary, free-swimming tunicates found throughout the world's oceans. While larvaceans are filter feeders like most other tunicates, they keep their tadpole-like shape as adults, with the notochord running through the tail. They can be found in the pelagic zone, specifically in the photic zone, or sometimes deeper. They are transparent planktonic animals, usually ranging from 2 mm (0.079 in) to 8 mm (0.31 in) in body length including the tail, although giant larvaceans can reach up to 10 cm (3.9 in) in length.
Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of a polysaccharide.
The lancelets, also known as amphioxi, consist of 32 described species of "fish-like" benthic filter feeding chordates in the subphylum Cephalochordata, class Leptocardii, and family Branchiostomatidae.
Ciona intestinalis is an ascidian, a tunicate with very soft tunic. Its Latin name literally means "pillar of intestines", referring to the fact that its body is a soft, translucent column-like structure, resembling a mass of intestines sprouting from a rock. It is a globally distributed cosmopolitan species. Since Linnaeus described the species, Ciona intestinalis has been used as a model invertebrate chordate in developmental biology and genomics. Studies conducted between 2005 and 2010 have shown that there are at least two, possibly four, sister species. More recently it has been shown that one of these species has already been described as Ciona robusta. By anthropogenic means, the species has invaded various parts of the world and is known as an invasive species.
Shark anatomy differs from that of bony fish in a variety of ways. Variation observed within shark anatomy is a potential result of speciation and habitat variation.
The fringefin lanternshark is a shark of the family Etmopteridae found in the western central Atlantic from Texas to Florida, northern Gulf of Mexico, and Mexico. It is endemic to this area. It is a deep water shark and is found about 220 to 915 meters below the surface, on the upper continental slopes of the Gulf. E. schultzi is a small shark, about 27–30 cm long and feeds on squid. It is also bioluminescent, which counter-illuminates it and helps with intraspecific interaction. Due to its limited range and the difficulty of collecting deep water species, it has not been evaluated by the IUCN Red List, but due to recent oil spills in the Gulf of Mexico, it is likely that fringefin lanternsharks have decreased in population.
The Chaco side-necked turtle is a species of turtle in the family Chelidae. It is found in Argentina, Paraguay, and possibly Bolivia. Its natural habitat is subtropical or tropical moist montane forests. The turtle possesses long horny spurs on its upper thighs. It is 18 cm in shell length. Like other members of its genus, the turtle buries itself in the mud when the streams run dry, a behaviour possibly parallel to the winter hibernating behaviours of turtles further north.
Oikopleura cophocerca is a species of small pelagic tunicate found in the surface waters of most of the world's oceans. It superficially resembles a tadpole and is surrounded by a transparent mucus net known as a "house".
Oikopleura dioica is a species of small pelagic tunicate found in the surface waters of most of the world's oceans. It is used as a model organism in research into developmental biology.
Aclis is a genus of small sea snails, marine gastropod mollusks in the family Eulimidae.
Oikopleuridae is a family of larvacean tunicates. A comparatively species-rich family, it has been especially well-researched thanks to the ubiquity of Oikopleura dioica as a model species. It comprises two subfamilies, Bathochordaeinae and Oikopleurinae, itself divided into the tribes Alabiata and Labiata.
Bathochordaeus, the giant larvaceans, is a genus of larvacean tunicates in the family Oikopleuridae. They are free-swimming filter-feeding marine animals that build mucus bubbles. They eat tiny particles of dead or drifting organic material that float through the water column, which contribute to the oceanic carbon cycle and the accelerated transfer of carbon to the deep sea.
Bassia is a monotypic siphonophore genus in the family Abylidae. The genus contains the single species Bassia bassensis.
Linda Zimmerman Holland is a research biologist at Scripps Institution of Oceanography known for her work examining the evolution of vertebrates.
Fritillaria is a genus of larvacean tunicates belonging to the family Fritillariidae.
