Porcelain crab

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Porcelain crabs
Temporal range: Tithonian–Recent
South eastern Pacific species of Petrolisthes, Allopetrolisthes, and Liopetrolisthes (Porcellanidae).jpg
Southeastern Pacific species of Petrolisthes, Allopetrolisthes and Liopetrolisthes
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Anomura
Superfamily: Galatheoidea
Family: Porcellanidae
Haworth, 1825
Genera

See text

Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attacked, and use their large claws for maintaining territories. They first appeared in the Tithonian age of the Late Jurassic epoch, 145–152 million years ago.

Contents

Description

Porcelain crabs are small, usually with body widths less than 15 millimetres (9/16 inch). [1] They share the general body plan of a squat lobster, but their bodies are more compact and flattened, an adaptation for living and hiding under rocks. [2] Porcelain crabs are quite fragile animals, and often shed their limbs to escape predators, [3] hence their name. The lost appendage can grow back over several moults. Porcelain crabs have large chelae (claws), which are used for territorial struggles, but not for catching food. [1] The fifth pair of pereiopods is reduced and used for cleaning. [4]

Evolution

Porcelain crabs are an example of carcinisation, whereby a noncrab-like animal (in this case a relative of a squat lobster) evolves into an animal that resembles a true crab. [5] [6] Porcelain crabs can be distinguished from true crabs by the apparent number of walking legs (three instead of four pairs; the fourth pair is reduced and held against the carapace), and the long antennae originating on the front outside of the eyestalks. [3] The abdomen of the porcelain crab is long and folded underneath it, free to move. [3]

Biogeography and ecology

Porcellana platycheles Pilumnus hirtellus millport.jpg
Porcellana platycheles
Neopetrolisthes maculatus Porcelain crab Nick Hobgood.jpg
Neopetrolisthes maculatus

Porcelain crabs live in all the world's oceans, except the Arctic Ocean and the Antarctic. [7] They are common under rocks, and can often be found and observed on rocky beaches and shorelines, startled creatures scurrying away when a stone is lifted. They feed by combing plankton and other organic particles from the water using long setae (feathery hair- or bristle-like structures) on the mouthparts. [4]

Some of the common species of porcelain crabs in the Caribbean Sea are Petrolisthes quadratus , found in large numbers under rocks in the intertidal, and the red-and-white polka-dotted Porcellana sayana , which lives commensally within the shells inhabited by large hermit crabs. In Hong Kong, Petrolisthes japonicus is common. [2]

Diversity

As of 2018, some 4723 extant species of porcelain crab had been described, [8] [ citation needed ] divided among these 30 genera: [8] [9]

The fossil record of porcelain crabs includes species of Pachycheles, Pisidia, Polyonyx, Porcellana, and a further six genera known only from fossils: [10]

The earliest claimed porcelain crab fossil was Jurellana from the Tithonian aged Ernstbrunn Limestone of Austria. [10] However, it was subsequently determined to be a true crab. With the new oldest porcelain crab being Vibrissalana from the same locality. [11]

Related Research Articles

<span class="mw-page-title-main">Pleocyemata</span> Suborder of crustaceans

Pleocyemata is a suborder of decapod crustaceans, erected by Martin Burkenroad in 1963. Burkenroad's classification replaced the earlier sub-orders of Natantia and Reptantia with the monophyletic groups Dendrobranchiata (prawns) and Pleocyemata. Pleocyemata contains all the members of the Reptantia, as well as the Stenopodidea, and Caridea, which contains the true shrimp.

<span class="mw-page-title-main">Squat lobster</span> Decapod crustaceans in the infraorder Anomura

Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside groups including the hermit crabs and mole crabs. They are distributed worldwide in the oceans, and occur from near the surface to deep sea hydrothermal vents, with one species occupying caves above sea level. More than 900 species have been described, in around 60 genera. Some species form dense aggregations, either on the sea floor or in the water column, and a small number are commercially fished.

<span class="mw-page-title-main">Anomura</span> Infraorder of crustaceans

Anomura is a group of decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word crab, all true crabs are in the sister group to the Anomura, the Brachyura.

<span class="mw-page-title-main">Carcinisation</span> Evolution of crustaceans into crab-like forms

Carcinisation is a form of convergent evolution in which non-crab crustaceans evolve a crab-like body plan. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "the many attempts of Nature to evolve a crab".

<i>Petrolisthes</i> Genus of crustaceans

Petrolisthes is a genus of marine porcelain crabs, containing these extant species:

<i>Neopetrolisthes maculatus</i> Species of crustacean

Neopetrolisthes maculatus is a species of porcelain crab from the Indo-Pacific region. It is a small, colourful crustacean with a porcelain-like shell. This porcelain crab is usually found within the stinging tentacles of a number of sea anemone species.

<span class="mw-page-title-main">Galatheidae</span> Family of crustaceans

The Galatheidae are a family of squat lobsters.

<span class="mw-page-title-main">Hippoidea</span> Superfamily of crustaceans

Hippoidea is a superfamily of decapod crustaceans known as mole crabs or sand crabs.

<i>Galathea</i> Genus of crustaceans

Galathea is a genus of squat lobsters in the family Galatheidae. It is one of the largest genera of squat lobsters that in 2008 contained 73 species. Most species of Galathea live in shallow waters.

<i>Munidopsis</i> Genus of crustaceans

Munidopsis is a genus of squat lobster. It is the second largest of all the genera of squat lobsters, after Munida, with over 200 species. Its members are mainly found on continental slopes and on abyssal plains. A few fossil species are also known, including specimens from the Campanian (Cretaceous).

<span class="mw-page-title-main">Galatheoidea</span> Superfamily of crustaceans

The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.

<i>Porcellana</i> Genus of crustaceans

Porcellana is a genus of decapod crustaceans in the widespread family Porcellanidae, the porcelain crabs, which superficially resemble true crabs. The genus Porcellana includes the following species:

Jurellana tithonia, the only species in the genus Jurellana, is a fossil crab. It was found in limestone rocks from the Ernstbrunn Formation in Austria, which have been dated to the Tithonian. It was originally thought to be the world's oldest porcelain crab, but was later determined to actually be a true crab.

<i>Allopetrolisthes spinifrons</i> Species of porcelain crab

Allopetrolisthes spinifrons is a species of porcelain crab. It displays "hypercarcinisation", whereby the resemblance to a true crab is enhanced by sexual dimorphism of the abdomen. It lives along the Pacific coast of Peru and Chile, as a symbiont of a sea anemone.

<i>Porcellana sayana</i> Species of crustacean

Porcellana sayana is a species of porcelain crab that lives in the western Atlantic Ocean, often as a commensal of hermit crabs. It is red with white spots, and has a characteristic bulge behind each claw.

<span class="mw-page-title-main">Munididae</span> Family of crustaceans

Munididae is a family of squat lobsters, taxonomically separated from the family Galatheidae in 2010.

<i>Petrolisthes armatus</i> Species of crustacean

Petrolisthes armatus, the green porcelain crab, is a species of small porcelain crab in the family Porcellanidae. It is believed to be native to Brazil but has spread to other parts of the world. Populations in the south eastern part of the United States have increased dramatically and the species is considered to be an invasive species.

<i>Polyonyx</i> Genus of crabs

Polyonyx is a genus of porcelain crabs in the family Porcellanidae. There are at least 42 described species in Polyonyx.

<i>Pachycheles</i> Genus of crustaceans

Pachycheles is a genus of porcelain crabs in the family Porcellanidae. There are more than 40 described species in Pachycheles.

References

  1. 1 2 Denny, Mark W. & Gaines, Steven Dean (2007). "Crabs". Encyclopedia of Tidepools and Rocky Shores. Encyclopedias of the Natural World, Issue 1. University of California Press. pp. 164–176. ISBN   978-0-520-25118-2.
  2. 1 2 Brian Morton & John Edward Morton (1993). "Boulder shores". The Sea Shore Ecology of Hong Kong. Hong Kong University Press. pp. 86–125. ISBN   978-962-209-027-9.
  3. 1 2 3 Gary C. B. Poore & Shane T. Ahyong (2004). "Porcellanidae Haworth, 1825". Marine decapod Crustacea of southern Australia: a guide to identification. CSIRO Publishing. pp. 242–246. ISBN   978-0-643-06906-0.
  4. 1 2 Allen, Gerald R. (1997). "Anemone crab Neopetrolisthes maculatus". Tropical Marine Life. Periplus Nature Guides. Tuttle Publishing. p. 35. ISBN   978-962-593-157-9.
  5. ↑ C. L. Morrison; A. W. Harvey; S. Lavery; K. Tieu; Y. Huang; C. W. Cunningham (2001). "Mitochondrial gene rearrangements confirm the parallel evolution of the crab-like form" (PDF). Proceedings of the Royal Society B . 269 (1489): 345–350. doi:10.1098/rspb.2001.1886. PMC   1690904 . PMID   11886621.
  6. ↑ Jonas Keiler, Stefan Richter & Christian S. Wirkner (2014). "Evolutionary morphology of the organ systems in squat lobsters and porcelain crabs (crustacea: Decapoda: Anomala): an insight into carcinization". Journal of Morphology . 276 (1): 1–21. doi:10.1002/jmor.20311. PMID   25156549. S2CID   26260996.
  7. ↑ P. McLaughlin, S. Ahyong & J. K. Lowry (October 2, 2002). "Porcellanidae Haworth, 1825". Anomura: Families. Australian Museum. Archived from the original on April 29, 2005. Retrieved February 10, 2005.
  8. 1 2 Masayuki Osawa & Patsy A. McLaughlin (2010). "Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea) Part II – Porcellanidae" (PDF). Zootaxa . Suppl. 23: 109–129. Archived from the original (PDF) on 2012-03-02.
  9. ↑ WoRMS (2010). "Porcellanidae". World Register of Marine Species . Retrieved November 13, 2010.
  10. 1 2 Carrie E. Schweitzer & Rodney M. Feldmann (2010). "Earliest known Porcellanidae (Decapoda: Anomura: Galatheoidea) (Jurassic: Tithonian)" (PDF). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen . 258 (2): 243–248. doi:10.1127/0077-7749/2010/0096.
  11. ↑ Robins, Cristina M; Klompmaker, Adiël A (2019-11-14). "Extreme diversity and parasitism of Late Jurassic squat lobsters (Decapoda: Galatheoidea) and the oldest records of porcellanids and galatheids". Zoological Journal of the Linnean Society. 187 (4): 1131–1154. doi: 10.1093/zoolinnean/zlz067 . ISSN   0024-4082.
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