''Thymops birsteini'', the Patagonian lobsterette, is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

lobster Lobsters are a family (Nephropidae, synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, including the first pair ...

found around the coasts of South America, particularly the

South Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe an ...

. It belongs to the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''Thymops''.

Distribution

''T. birsteini'' is found on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

around South America, particularly in the Argentine Sea. In the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe ...

, it is found south of 37° south, with

Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...

representing the northern extremity of its distribution; on the

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

an (

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

) side, it is found south of 51° south. Its range includes the areas around the

Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubou ...

(''Islas Malvinas'') and areas near South Georgia, extending as far south as 57°, close to the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

. It lives at depths of .

Description

''T. birsteini'' resembles a typical lobster, with two large

claw A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes ( mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or t ...

s, four other pairs of pereiopods, and a long pleon (tail). The

carapace A carapace is a dorsal (upper) 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 under ...

is granular, especially in the front half, and it bears a

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * R ...

which divides into two points at its tip. The total length may range from , with the carapace being long. Smaller individuals are found in shallower waters, and larger individuals are found at greater depths (up to ). There is also latitudinal variation in colour, with northern individuals being pale yellow, while those from further south are maroon.

Ecology

Little is known about the biological interactions of ''T. birsteini''. It is occasionally eaten by the

Patagonian toothfish The Patagonian toothfish (''Dissostichus eleginoides'') is a species of notothen found in cold waters () between depths of in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most ...

''Dissostichus eleginoides''. It seems to prefer

mud A MUD (; originally multi-user dungeon, with later variants multi-user dimension and multi-user domain) is a multiplayer real-time virtual world, usually text-based or storyboarded. MUDs combine elements of role-playing games, hack and slash ...

dy bottoms, and has been observed entering and exiting

burrow An Eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of s ...

Life cycle

As in other pleocyemates, ''T. birsteini'' broods its

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

on the female's

pleopod The decapod ( crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various ...

s. One female may carry up to 380 eggs, each in diameter. The eggs grow as they develop to a size of . Newly hatched

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e have a carapace length of , and are present in smaller numbers than the eggs, with a maximum of 43 observed on a single female. This extended larval release has previously been found in other sub-Antarctic decapods, and is an

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

to the low

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

, the long time taken for brooding, and the low overall

fecundity Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to p ...

Edibility

The meat of ''T. birsteini'' is reported to be excellent, and it is thought that the species could be commercially exploited if sufficient concentrations could be discovered. The average weight of a caught individual is about , of which 30% () is the meaty tail. Daily yields of are typical.

References

{{Taxonbar, from=Q1170796 True lobsters Crustaceans of the Atlantic Ocean Monotypic arthropod genera Edible crustaceans Western South American coastal fauna Fauna of Temperate South America