Leptostraca (from the Greek words for thin and shell)[3] 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.[4] 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.[5]
Leptostraca Temporal range:
| |
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Nebalia bipes | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Subclass: | Phyllocarida |
Order: | Leptostraca Claus, 1880 [1] |
Families [2] | |
Description
editLeptostracans are usually small, typically 5 to 15 millimetres (0.2 to 0.6 in) long,[7] but the largest species (Nebaliopsis typica) can reach 4 cm, and the Silurian Ceratiocaris could grow to 75 cm.[8] 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.[4] 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.[9][10][11]
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.[5]
Classification
editIt is now accepted that leptostracans belong to the Malacostraca,[12] and the sister crown group to Leptostraca is Eumalacostraca.[13]
The Order Leptostraca is divided into three families, with ten genera containing a total of around 40 validly described extant species:[14]
References
edit- ^ "Leptostraca". Integrated Taxonomic Information System. Retrieved October 28, 2010.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af Genefor K. Walker-Smith; Gary C. B. Poore (2001). "A phylogeny of the Leptostraca (Crustacea) with keys to families and genera". Memoirs of Museum Victoria. 58 (2): 383–410. doi:10.24199/j.mmv.2001.58.21.
- ^ "Leptostraca". Online Medical Dictionary. March 1, 1998.
- ^ a b J. K. Lowry (October 2, 1999). "Leptostraca". Crustacea, the Higher Taxa: Description, Identification, and Information Retrieval. Australian Museum. Archived from the original on September 23, 2017. Retrieved August 8, 2007.
- ^ a b Robert D. Barnes (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 708–709. ISBN 978-0-03-056747-6.
- ^ Leptostraca (Crustacea: Phyllocarida: Nebaliidae) from French coastal waters: new records and new data on their ecology and distribution
- ^ Estela C. Lopretto (July 30, 2003). "Phyllocarida". Answers.com.
- ^ Invertebrate Palaeontology and Evolution
- ^ F. Knopf; S. Koenemann; F. R. Schram & C. Wolff (2006). "The urosome of the Pan- and Peracarida" (PDF). Contributions to Zoology. 75 (1/2): 1–21. doi:10.1163/18759866-0750102001. Archived from the original (PDF) on 2007-10-14. Retrieved 2007-08-08.
- ^ A phylogeny of the Leptostraca (Crustacea) with keys to families and genera
- ^ Multicellular Animals: Volume II: The Phylogenetic System of the Metazoa
- ^ J. W. Martin; G. E. Davis (2001). An Updated Classification of the Recent Crustacea (PDF). Natural History Museum of Los Angeles County. pp. 132 pp. Archived from the original (PDF) on 2013-05-12. Retrieved 2009-12-14.
- ^ "Malacostraca". Tree of Life Web Project. January 1, 2002.
- ^ Todd Haney (2004). "Classification". Natural History Museum of Los Angeles County. Archived from the original on October 14, 2013. Retrieved August 8, 2007.
- ^ 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". Zoologichesky Zhurnal (in Russian). 75 (12): 1892–1896.
- ^ Todd Haney. "Synonymy". Los Angeles PEET Project on Leptostraca. Natural History Museum of Los Angeles County. Archived from the original on September 6, 2008. Retrieved February 28, 2009.
- ^ Todd A. Haney & Joel W. Martin (2005). Boyko, Christopher B. (ed.). "Nebalia kensleyi, a new species of leptostracan (Crustacea: Phyllocarida) from Tomales Bay, California" (PDF). Proceedings of the Biological Society of Washington. 118 (l): 3–20. doi:10.2988/0006-324X(2005)118[3:NKANSO]2.0.CO;2. Archived from the original (PDF) on 2011-07-27. Retrieved 2009-02-28.
- ^ Juan Moreira; Cengiz Kocak; Tuncer Katagan (2007). "Nebalia kocatasi sp. nov., a new species of leptostracan (Crustacea: Phyllocarida) from Izmir Bay (Aegean Sea, eastern Mediterranean)". Journal of the Marine Biological Association of the United Kingdom. 87 (5): 1247–1254. doi:10.1017/S0025315407057487.
- ^ Ji-Hun Song; Juan Moreira; Gi-Sik Min (2012). "A New Species of Leptostraca, Nebalia koreana (Malacostraca: Phyllocarida), from South Korea". Journal of Crustacean Biology. 32 (4): 641–653. doi:10.1163/193724012X638482.
- ^ Todd A. Haney; Robert R. Hessler; Joel W. Martin (2001). "Nebalia schizophthalma, a new species of Leptostracan (Malacostraca) from deep waters off the east coast of the United States" (PDF). Journal of Crustacean Biology. 21 (1): 192–201. doi:10.1651/0278-0372(2001)021[0192:NSANSO]2.0.CO;2. Archived from the original (PDF) on 2011-07-27. Retrieved 2009-02-28.
- ^ Juan Moreira; Eva Cacabelos; Marta Domínguez (2003). "Nebalia troncosoi sp. nov., a new species of leptostracan (Crustacea: Phyllocarida: Leptostraca) from Galicia, Iberian Peninsula (north-east Atlantic)". Journal of the Marine Biological Association of the United Kingdom. 83 (2): 341–350. doi:10.1017/S0025315403007173h. S2CID 86253676.
- ^ a b 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. doi:10.1080/00364820310001390. S2CID 84442419.
- ^ 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" (PDF). Journal of Natural History. 38 (4): 447–469. doi:10.1080/0022293021000033210. S2CID 51695603. Archived from the original (PDF) on 2011-07-27. Retrieved 2009-02-28.
External links
edit- Media related to Leptostraca at Wikimedia Commons
- Data related to Leptostraca at Wikispecies