Leptostraca Explained

Leptostraca (from the Greek words for thin and shell)[1] 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.[2] It is the only extant order in the subclass Phyllocarida. They are believed to represent the most primitive members of their class, the Malacostraca, and first appear in the fossil record during the Cambrian period.

Description

Leptostracans are usually small, typically 5mm15mm long,[3] but the largest species (Nebaliopsis typica) can reach 4 cm, and the Silurian Ceratiocaris could grow to 75 cm.[4] They are distinguished from all other members of their class in having seven abdominal segments, instead of six. Their head has stalked compound eyes, two pairs of antennae (one biramous, one uniramous), and a pair of mandibles but no maxillipeds.[2] They are the only malacostracans with a carapace that comprises two valves. It covers the head and the thorax, including most of the thoracic appendages, and serves as a brood pouch for the developing embryos. Its anterior tip bears a movable rostrum. Also unique among malacostracans is their eight pairs of thoracic appendages which have been specialized into leaf-like filter feeding organs, and are not used for locomotion. The first six abdominal segments bear pleopods, while the seventh bears a pair of caudal furcae, which may be homologous to uropods of other crustaceans.[5] [6] [7]

Leptostracans have gills on their thoracic limbs, but also breathe through a respiratory membrane on the inside of the carapace. The eggs hatch as a postlarval, or "manca" stage, which lacks a fully developed carapace, but otherwise resembles the adult.[8]

Classification

It is now accepted that leptostracans belong to the Malacostraca,[9] and the sister crown group to Leptostraca is Eumalacostraca.[10]

The Order Leptostraca is divided into three families, with ten genera containing a total of around 40 validly described extant species:[11]

Species Authority Date Family Distribution
Nebaliopsis typica Sars 1887 Nebaliopsididae Southern Hemisphere [12]
Pseudonebaliopsis atlantica Petryachov 1996 Nebaliopsididae North Atlantic [13]
Nebalia antarctica Dahl 1990 Nebaliidae Antarctica 
Nebalia bipes Fabricius 1780 Nebaliidae Arctic and sub-Arctic 
Nebalia borealis Dahl 1985 Nebaliidae north-east Atlantic Ocean 
Nebalia brucei Olesen 1999 Nebaliidae Tanzania 
Nebalia cannoni Dahl 1990 Nebaliidae South Georgia 
Nebalia capensis Barnard 1914 Nebaliidae South Africa 
Nebalia clausi Dahl 1985 Nebaliidae Italy 
Nebalia dahli Kazmi & Tirmizi 1989 Nebaliidae Pakistan 
Nebalia daytoni Vetter 1996 Nebaliidae California 
Nebalia falklandensis Dahl 1990 Nebaliidae Falkland Islands
Nebalia geoffroyi Milne-Edwards 1828 Nebaliidae north-east Atlantic Ocean [14]
Nebalia gerkenae Haney & Martin 2000 Nebaliidae California 
Nebalia herbstii Leach 1814 Nebaliidae north-east Atlantic Ocean 
Nebalia hessleri Martin et al. 1996 Nebaliidae California 
Nebalia ilheoensis Kensley 1976 Nebaliidae south-western Africa 
Nebalia kensleyi Haney & Martin 2005 Nebaliidae California [15]
Nebalia kocatasi Kocak, Moreira & Katagan 2007 Nebaliidae Mediterranean Sea [16]
Nebalia koreana Song, Moreira & Min 2012 Nebaliidae South Korea [17]
Nebalia lagartensis Escobar & Villalobos-Hiriart 1995 Nebaliidae Mexico 
Nebalia longicornis Thomson 1879 Nebaliidae South Pacific, South Africa, Caribbean Sea 
Nebalia marerubi Wägele 1983 Nebaliidae Red Sea 
Nebalia patagonica Dahl 1990 Nebaliidae Magellan region 
Nebalia schizophthalma Haney, Hessler & Martin 2001 Nebaliidae western Atlantic Ocean [18]
Nebalia strausi Risso 1826 Nebaliidae north-east Atlantic Ocean, Mediterranean Sea 
Nebalia troncosoi Moreira, Cacabelos & Dominguez 2003 Nebaliidae Spain [19]
Nebaliella antarctica Thiele 1904 Nebaliidae Kerguelen, New Zealand 
Nebaliella brevicarinata Kikuchi & Gamô 1992 Nebaliidae Antarctica 
Nebaliella caboti Clark 1932 Nebaliidae Cabot Strait, New Jersey 
Nebaliella declivatas Walker-Smith 1998 Nebaliidae Australia 
Nebaliella extrema Thiele 1905 Nebaliidae Antarctica 
Dahlella caldariensis Hessler 1984 Nebaliidae East Pacific Rise 
Sarsinebalia cristobi Moreira, Gestoso & Troncoso 2003 Nebaliidae north-east Atlantic Ocean [20]
Sarsinebalia typhlops 1870 Nebaliidae North Atlantic, Australia 
Sarsinebalia urgorrii Moreira, Gestoso & Troncoso 2003 Nebaliidae north-east Atlantic Ocean 
Speonebalia cannoni Bowman, Yager & Iliffe 1985 Nebaliidae Turks and Caicos Islands 
Levinebalia fortunata 1976 Paranebaliidae New Zealand 
Levinebalia maria Walker-Smith 2000 Paranebaliidae Australia 
Paranebalia belizensis Modlin 1991 Paranebaliidae Belize 
Paranebalia longipes 1875 Paranebaliidae Atlantic, Pacific and Indian Oceans 
Saronebalia guanensis Haney & Martin 2004 Paranebaliidae British Virgin Islands [21]

Notes and References

  1. Web site: Leptostraca . . March 1, 1998.
  2. Web site: Leptostraca . J. K. Lowry . Crustacea, the Higher Taxa: Description, Identification, and Information Retrieval . October 2, 1999 . . August 8, 2007 . https://web.archive.org/web/20170923034139/http://www.crustacea.net/crustace/www/leptostr.htm . September 23, 2017 . dead .
  3. Web site: Phyllocarida. Estela C. Lopretto . . July 30, 2003 .
  4. https://books.google.no/books?id=ozNIDAAAQBAJ&pg=PT660&dq=Ceratiocaris+75+Nebaliopsis&hl=no&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwipk8PtrMOGAxUIIhAIHSxqCxUQ6AF6BAgIEAI#v=onepage&q=Ceratiocaris%2075%20Nebaliopsis&f=false Invertebrate Palaeontology and Evolution
  5. The urosome of the Pan- and Peracarida . F. Knopf . S. Koenemann . F. R. Schram . Frederick Schram . C. Wolff . amp . 2006 . . 75 . 1/2 . 1–21 . 10.1163/18759866-0750102001 . 2007-08-08 . 2007-10-14 . https://web.archive.org/web/20071014165817/http://www.tiho-hannover.de/einricht/botanik/koenemann/knopfetal06.pdf . dead .
  6. https://museumsvictoria.com.au/media/3996/58_2_walker.pdf A phylogeny of the Leptostraca (Crustacea) with keys to families and genera
  7. https://books.google.no/books?id=x7vtCAAAQBAJ&pg=PA162&dq=Leptostraca+carapace+two+valves+turgor&hl=no&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwiciKH-zcWGAxUEGxAIHcMmHUUQ6AF6BAgKEAI#v=onepage&q=Leptostraca%20carapace%20two%20valves%20turgor&f=false Multicellular Animals: Volume II: The Phylogenetic System of the Metazoa
  8. Book: Robert D. Barnes . 1982 . Invertebrate Zoology . . Philadelphia, PA . 708–709. 978-0-03-056747-6.
  9. Book: An Updated Classification of the Recent Crustacea . J. W. Martin . G. E. Davis . 2001 . 132 pp . . 2009-12-14 . 2013-05-12 . https://web.archive.org/web/20130512091254/http://atiniui.nhm.org/pdfs/3839/3839.pdf . dead .
  10. Web site: Malacostraca . . January 1, 2002.
  11. Web site: Classification . . 2004 . Todd Haney . August 8, 2007 . October 14, 2013 . https://web.archive.org/web/20131014171839/http://crustacea.nhm.org/peet/leptostraca/classification.html . dead .
  12. Genefor K. Walker-Smith . Gary C. B. Poore . 2001 . A phylogeny of the Leptostraca (Crustacea) with keys to families and genera . . 58 . 2 . 383–410 . 10.24199/j.mmv.2001.58.21 . free .
  13. V. V. Petryashov . 1996 . Pseudonebaliopsis atlantica gen. n., sp. n., is a new genus and a new species of Leptostraca (Crustacea, Malacostraca) from the central part of the North Atlantic . . 75 . 12 . 1892–1896 . Russian.
  14. Web site: Synonymy . Los Angeles PEET Project on Leptostraca . Todd Haney . February 28, 2009 . . dead . https://web.archive.org/web/20080906133441/http://crustacea.nhm.org/peet/leptostraca/synonymies.html . September 6, 2008 .
  15. Nebalia kensleyi, a new species of leptostracan (Crustacea: Phyllocarida) from Tomales Bay, California . . 118 . l . 3–20 . 2005 . Todd A. Haney . Joel W. Martin . amp . 10.2988/0006-324X(2005)118[3:NKANSO]2.0.CO;2 . Boyko . Christopher B. . 2009-02-28 . 2011-07-27 . https://web.archive.org/web/20110727025757/http://atiniui.nhm.org/pdfs/10200/10200.pdf . dead .
  16. . 2007 . 87 . 5 . 1247–1254 . 10.1017/S0025315407057487 . Nebalia kocatasi sp. nov., a new species of leptostracan (Crustacea: Phyllocarida) from Izmir Bay (Aegean Sea, eastern Mediterranean) . Juan Moreira . Cengiz Kocak . Tuncer Katagan .
  17. . 2012 . 32 . 4 . 641–653 . 10.1163/193724012X638482 . A New Species of Leptostraca, Nebalia koreana (Malacostraca: Phyllocarida), from South Korea . Ji-Hun Song . Juan Moreira . Gi-Sik Min . free .
  18. Nebalia schizophthalma, a new species of Leptostracan (Malacostraca) from deep waters off the east coast of the United States . Todd A. Haney . Robert R. Hessler . Joel W. Martin . . 21 . 1 . 192–201 . 2001 . 10.1651/0278-0372(2001)021[0192:NSANSO]2.0.CO;2 . 2009-02-28 . 2011-07-27 . https://web.archive.org/web/20110727025853/http://atiniui.nhm.org/pdfs/4327/4327.pdf . dead .
  19. . 2003 . 83 . 2 . 341–350 . 10.1017/S0025315403007173h . Nebalia troncosoi sp. nov., a new species of leptostracan (Crustacea: Phyllocarida: Leptostraca) from Galicia, Iberian Peninsula (north-east Atlantic) . Juan Moreira . Eva Cacabelos . Marta Domínguez . 86253676 .
  20. J. Moreira . L. Gestoso . J. S. Troncoso . 2003 . Two new species of Sarsinebalia (Crustacea, Leptostraca) from the Northeast Atlantic, with comments on the genus . Sarsia: North Atlantic Marine Science . 88 . 3 . 189–209 . 10.1080/00364820310001390. 84442419 .
  21. Todd Haney . Joel W. Martin . 2004 . A new genus and species of leptostracan (Crustacea: Malacostraca: Phyllocarida) from Guana Island, British Virgin Islands, and a review of leptostracan genera . . 38 . 4 . 447–469 . 10.1080/0022293021000033210 . 51695603 . 2009-02-28 . 2011-07-27 . https://web.archive.org/web/20110727025904/http://atiniui.nhm.org/pdfs/10028/10028.pdf . dead .

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