''Porcellanopagurus edwardsi'' is a species of

hermit crab Hermit crabs are anomuran Decapoda, decapod crustaceans of the superfamily (taxonomy), superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit c ...

that lives in the waters around

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and its

subantarctic islands The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region inc ...

Distribution

''Porcellanopagurus edwardsi'' is found around the

Auckland Islands The Auckland Islands ( Māori: ''Motu Maha'' "Many islands" or ''Maungahuka'' "Snowy mountains") are an archipelago of New Zealand, lying south of the South Island. The main Auckland Island, occupying , is surrounded by smaller Adams Island ...

Campbell Islands The Campbell Islands (or Campbell Island Group) are a group of subantarctic islands, belonging to New Zealand. They lie about 600 km south of Stewart Island. The islands have a total area of , consisting of one big island, Campbell Is ...

Snares Islands The Snares Islands (; officially Snares Islands / Tini Heke), known colloquially as The Snares, is a group of uninhabited islands lying about south of New Zealand's South Island and to the south-southwest of Stewart Island / Rakiura. The Snar ...

Stewart Island Stewart Island (, ' glowing skies', officially Stewart Island / Rakiura, formerly New Leinster) is New Zealand's third-largest island, located south of the South Island, across Foveaux Strait. It is a roughly triangular island with a la ...

and along the coast of New Zealand's

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

. The closely related species '' P. filholi'' has a more northerly distribution, overlapping with that of ''P. edwardsi'' only in the region of the

Banks Peninsula Banks Peninsula () is a rocky peninsula on the east coast of the South Island of New Zealand that was formed by two now-extinct volcanoes. It has an area of approximately . It includes two large deep-water harbours — Lyttelton Harbour a ...

. pp. 110–114
''P. edwardsi''
pp. 114–117
''P. filholi''
They are benthic, and live at a depth range of 1-120m.

Taxonomy

''Porcellanopagurus edwardsi'' was described by

Henri Filhol Henri Filhol Henri Filhol (13 May 1843 – 28 April 1902) was a French medical doctor, malacologist and naturalist born in Toulouse. He was the son of Édouard Filhol (1814-1883), curator of the Muséum de Toulouse. After receiving his early e ...

in 1885 as the only species in a new genus ''

Porcellanopagurus ''Porcellanopagurus'' is a genus of hermit crabs. The genus occurs in the Pacific and Indian Oceans. Description ''Porcellanopagurus'' is unusual among hermit crabs in that the body is largely symmetrical, with the abdomen held recurved above th ...

''; 12 further species have since been described.

Life cycle

''P. edwardsi'' is mostly gonochoric as most members of the order

Decapoda The Decapoda or decapods, from Ancient Greek δεκάς (''dekás''), meaning "ten", and πούς (''poús''), meaning "foot", is a large order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, a ...

are. When mating, they commonly have a courtship ritual and indirectly transfer sperm.

Description

Unlike most hermit crabs, ''Porcellanopagurus edwardsi'' is almost

symmetrical Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is invariant under some transformations ...

, but its abdomen is bent back over the carapace, so that the

pleopod The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these m ...

s are dorsally situated. The abdomen is "grossly distorted", and is usually covered by the shell of a

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

limpet Limpets are a group of aquatic snails with a conical gastropod shell, shell shape (patelliform) and a strong, muscular foot. This general category of conical shell is known as "patelliform" (dish-shaped). Existing within the class Gastropoda, ...

, in contrast to the

gastropod shell The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium ...

used by most hermit crabs. The

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

is flattened and extends outwards in a number of lobes, the largest of which is the

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * 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 ...

at the front of the animal.PDF
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Distribution

Taxonomy

Life cycle

Description

References

Further reading