Leptostraca

Leptostraca Temporal range: Cambrian–Recent PreЄ Є O S D C P T J K Pg N
Nebalia bipes
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Subclass:	Phyllocarida
Order:	Leptostraca Claus, 1880 [1]
Families [2]
Nebaliidae Nebaliopsididae Paranebaliidae † Rhabdouraeidae

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]

Description

Diagram of Nebalia bipes showing the major features of the external anatomy: 1: antennule; 2: rostrum; 3: carapace; 4: abdomen / pleon; 5: furca; 6: telson; 7: pleopods; 8: antenna; 9: thoracopods; 10: eye

Leptostracans are usually small, typically 5 to 15 millimetres (0.2 to 0.6 in) long,^[6] crustaceans 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] The carapace is large and comprises two valves which cover the head and the thorax, including most of the thoracic appendages, and serves as a brood pouch for the developing embryos. 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.^[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.^[5]

Classification

It is now accepted that leptostracans belong to the Malacostraca,^[8] and the sister crown group to Leptostraca is Eumalacostraca.^[9]

The Order Leptostraca is divided into three families, with ten genera containing a total of around 40 validly described extant species:^[10]

Species	Authority	Date	Family	Distribution
Nebaliopsis typica	Sars	1887	Nebaliopsididae	Southern Hemisphere [2]
Pseudonebaliopsis atlantica	Petryachov	1996	Nebaliopsididae	North Atlantic [11]
Nebalia antarctica	Dahl	1990	Nebaliidae	Antarctica [2]
Nebalia bipes	Fabricius	1780	Nebaliidae	Arctic and sub-Arctic [2]
Nebalia borealis	Dahl	1985	Nebaliidae	north-east Atlantic Ocean [2]
Nebalia brucei	Olesen	1999	Nebaliidae	Tanzania [2]
Nebalia cannoni	Dahl	1990	Nebaliidae	South Georgia [2]
Nebalia capensis	Barnard	1914	Nebaliidae	South Africa [2]
Nebalia clausi	Dahl	1985	Nebaliidae	Italy [2]
Nebalia dahli	Kazmi & Tirmizi	1989	Nebaliidae	Pakistan [2]
Nebalia daytoni	Vetter	1996	Nebaliidae	California [2]
Nebalia falklandensis	Dahl	1990	Nebaliidae	Falkland Islands
Nebalia geoffroyi	Milne-Edwards	1828	Nebaliidae	north-east Atlantic Ocean [12]
Nebalia gerkenae	Haney & Martin	2000	Nebaliidae	California [2]
Nebalia herbstii	Leach	1814	Nebaliidae	north-east Atlantic Ocean [2]
Nebalia hessleri	Martin et al.	1996	Nebaliidae	California [2]
Nebalia ilheoensis	Kensley	1976	Nebaliidae	south-western Africa [2]
Nebalia kensleyi	Haney & Martin	2005	Nebaliidae	California [13]
Nebalia kocatasi	Kocak, Moreira & Katagan	2007	Nebaliidae	Mediterranean Sea [14]
Nebalia koreana	Song, Moreira & Min	2012	Nebaliidae	South Korea [15]
Nebalia lagartensis	Escobar & Villalobos-Hiriart	1995	Nebaliidae	Mexico [2]
Nebalia longicornis	Thomson	1879	Nebaliidae	South Pacific, South Africa, Caribbean Sea [2]
Nebalia marerubi	Wägele	1983	Nebaliidae	Red Sea [2]
Nebalia patagonica	Dahl	1990	Nebaliidae	Magellan region [2]
Nebalia schizophthalma	Haney, Hessler & Martin	2001	Nebaliidae	western Atlantic Ocean [16]
Nebalia strausi	Risso	1826	Nebaliidae	north-east Atlantic Ocean, Mediterranean Sea [2]
Nebalia troncosoi	Moreira, Cacabelos & Dominguez	2003	Nebaliidae	Spain [17]
Nebaliella antarctica	Thiele	1904	Nebaliidae	Kerguelen, New Zealand [2]
Nebaliella brevicarinata	Kikuchi & Gamô	1992	Nebaliidae	Antarctica [2]
Nebaliella caboti	Clark	1932	Nebaliidae	Cabot Strait, New Jersey [2]
Nebaliella declivatas	Walker-Smith	1998	Nebaliidae	Australia [2]
Nebaliella extrema	Thiele	1905	Nebaliidae	Antarctica [2]
Dahlella caldariensis	Hessler	1984	Nebaliidae	East Pacific Rise [2]
Sarsinebalia cristobi	Moreira, Gestoso & Troncoso	2003	Nebaliidae	north-east Atlantic Ocean [18]
Sarsinebalia typhlops	(Sars)	1870	Nebaliidae	North Atlantic, Australia [2]
Sarsinebalia urgorrii	Moreira, Gestoso & Troncoso	2003	Nebaliidae	north-east Atlantic Ocean [18]
Speonebalia cannoni	Bowman, Yager & Iliffe	1985	Nebaliidae	Turks and Caicos Islands [2]
Levinebalia fortunata	(Wakabara)	1976	Paranebaliidae	New Zealand [2]
Levinebalia maria	Walker-Smith	2000	Paranebaliidae	Australia [2]
Paranebalia belizensis	Modlin	1991	Paranebaliidae	Belize [2]
Paranebalia longipes	(Willemöes-Suhm)	1875	Paranebaliidae	Atlantic, Pacific and Indian Oceans [2]
Saronebalia guanensis	Haney & Martin	2004	Paranebaliidae	British Virgin Islands [19]

References

1. "Leptostraca". Integrated Taxonomic Information System. Retrieved October 28, 2010.
2. Genefor K. Walker-Smith & Gary C. B. Poore (2001). "A phylogeny of the Leptostraca (Crustacea) with keys to families and genera" (PDF). Memoirs of Museum Victoria 58 (2): 383–410.
3. "Leptostraca". Online Medical Dictionary. March 1, 1998.
4. J. K. Lowry (October 2, 1999). "Leptostraca". Crustacea, the Higher Taxa: Description, Identification, and Information Retrieval. Australian Museum.
5. Robert D. Barnes (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 708–709. ISBN 0-03-056747-5.
6. Estela C. Lopretto (July 30, 2003). "Phyllocarida". Answers.com.
7. 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.
8. 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.
9. "Malacostraca". Tree of Life Web Project. January 1, 2002.
10. Todd Haney (2004). "Classification". Natural History Museum of Los Angeles County. Retrieved August 8, 2007.
11. 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.
12. Todd Haney. "Synonymy". Los Angeles PEET Project on Leptostraca. Natural History Museum of Los Angeles County. Retrieved February 28, 2009.
13. 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.
14. 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.
15. 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.
16. 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.
17. 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.
18. 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.
19. 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: 447–469. doi:10.1080/0022293021000033210.