Oikopleura is a genusoftunicates in the class Appendicularia (larvaceans). It forms a mucus house every four hours at 20 degrees Celsius. This house has a coarse mesh to keep out big particles, and a fine mesh that collects the small particles, down to the nanoplankton that includes (pelagic) bacteria.
Abandoned mucus houses sink to the deep, collecting organic particles during their descent. They make an important contribution to marine snow, since Oikopleura is abundant and is a very active filterer, using powerful strokes of its tail. Its abundance is less obvious from preserved samples (that are usually analyzed) because the gelatinous body disappears in the preservation process while leaving hardly any trace.
Species of Oikopleura have the smallest genomes in the animal kingdom, only about 75Mb.
Oikopleura contains bioluminescent species.[1] About half of Oikopleura species are bioluminescent.[2][3]
The genus name comes from oikos (meaning "house") and pleura ("rib", or "side of the body"), referring to their ability to build a mucus house like other larvaceans.[4]
Oikopleura has been found to possibly be paraphyletic with respect to several other oikopleurid genera, namely: Folia, Stegosoma, Mesoikopleura, and Megalocercus. The genus might also harbour more diversity than thought, with species complexes like Oikopleura dioica comprising several reproductively incompatible clades despite consistent general morphology.[5]
A species of particular interest under this genus is the Oikopleura dioica, which is an anomaly among chordates. It has retained the fundamental body plan of the chordate; yet, it has lost the mechanism for retinoic acid signaling which operates during chordate development. The loss raises the question of the evolutionary constraints that have prevented similar changes in the other chordates.[20]
Oikopleura dioicahox genes are distributed in nine locations around the genome whereas other chordates have a cluster of hox genes.[21] Of note, this is the first chordate among the eukaryotes found to have operons.[22]
^Herring, Peter J. (1987). "Systematic distribution of bioluminescence in living organisms". Journal of Bioluminescence and Chemiluminescence. 1 (3): 147–163. doi:10.1002/bio.1170010303. PMID3503524.
^Flores-Coto C. 1965: Notas preliminares sobre la identificación de las apendicularias de las aguas veracruzanas. Anales del Instituto de Biología (México) 35: 293-296.
^Flores-Coto C.. 1974: Contribución al conocimiento de las apendicularias del arrecife “La Blanquilla” Veracruz, México con descripción de una nueva especie. Anales del Centro de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México 1: 41-60.
^Flores-Coto, César., Sanvicente-Añorve, Laura. & Sánchez-Ramírez, Marina. 2010: Appendicularian distribution and diversity in the southern Gulf of Mexico. Distribución y diversidad de apendicularias en el sur del golfo de México. Revista Mexicana de Biodiversidad, 81:123- 131. PDFArchived 2016-03-04 at the Wayback Machine
^Castellanos, I. A. and E. Suárez-Morales. 2009. Appendicularia (Urochordata) of the Gulf of Mexico, Pp. 1217–1221 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas.
^Márquez, Brightdoom., Marín, Baumar., Zoppi, Evelyn. & Moreno, Carlos. 2006: Zooplancton del Golfo De Cariaco. Bol. Inst. Oceanogr. Venezuela, Univ. Oriente.45(1):61-78 PDFArchived 2011-03-22 at the Wayback Machine
^Zoopp, Evelyn. 1971: Apendicularias de la Región Oriental de Venezuela. Studies on the Fauna of Curaçao and other caribbean Island, 132:76-109. Lam I – VI.
^Esnal G. 1972: Apendicularias de la desembocadura del Río de la Plata. Physis (Argentina) 31: 259-272.
^Esnal G. 1973: Apendicularias de las costas argentinas. Physis (Argentina) 32: 267-273.
^Esnal G. 1979: Características generales de la distribución de tunicados pelágicos del Atlántico sudoccidental, con algunas observaciones morfológicas. Physis (Argentina) 38: 91-102.
^Esnal G. 1981: Apendicularia. In: Boltovskoy (ed) Atlas del zooplancton del Atlántico sudoccidental y métodos de trabajo con el zooplancton marino: 809-820. Publicación Especial, Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Argentina. 936 pp.
^Esnal G. 1999: Appendicularia. In: Boltovskoy D (ed). South Atlantic zooplancton: 1375-1399. Backhuys Publication, Leiden, The Netherlands.
^Esnal, G.; Castro, R. (1977). "Distributional and biometrical study of appendicularians from the west south Atlantic. Ocean". Hydrobiologia. 56 (3): 241. doi:10.1007/bf00017510. S2CID21118473.
