Dahlella caldariensis is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of leptostraca

Leptostraca

Leptostraca is an order of small, marine crustaceans. Its members, including the well-studied Nebalia, occur throughout the world's oceans and are usually considered to be filter-feeders. It is the only extant order in the subclass Phyllocarida...

n crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

 which lives on hydrothermal vent

Hydrothermal vent

A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...

s in the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

.

Description

Dahlella may reach a length of 8.1 mm (0.318897637795276 in) from the base of the rostrum

Rostrum (anatomy)

The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

 to the end of the abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

. Much of the animal is covered by a large, hinged carapace

Carapace

A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...

.
Dahlella can be distinguished from other animals in the same family by the presence of a row of denticles (small teeth) on the eyestalk

Eyestalk

In anatomy, an eyestalk is a protrusion that extends the eye away from the body, giving the eye a better field of view than if it were unextended. It is common in nature and in fiction....

s, which it is believed are used to scrape surfaces for food. A similar character is found in Paranebalia (Paranebaliidae), but the form of the eyestalk is very different in the two taxa.

Distribution

D. caldariensis has been recorded from a small number of sites around hydrothermal vent

Hydrothermal vent

A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...

s in the eastern Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 near the Galápagos Islands

Galápagos Islands

The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...

 and on the East Pacific Rise

East Pacific Rise

The East Pacific Rise is a mid-oceanic ridge, a divergent tectonic plate boundary located along the floor of the Pacific Ocean. It separates the Pacific Plate to the west from the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate...

. It is one of the deepest-living species of Leptostraca, having been found at depths of over 2300 m (7,545.9 ft).

Etymology

The generic name Dahlella commemorates the biologist Erik Dahl of the University of Lund

Lund University

Lund University , located in the city of Lund in the province of Scania, Sweden, is one of northern Europe's most prestigious universities and one of Scandinavia's largest institutions for education and research, frequently ranked among the world's top 100 universities...

. The specific epithet comes from the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 word meaning hot bath

Caldarium

right|thumb|230px|Caldarium from the Roman Baths at [[Bath, England]]. The floor has been removed to reveal the empty space where the hot air flowed through to heat the floor....

, and is a reference to the natural habitat of D. caldariensis.