Tunicata: Peuplements d'ascidies profondes en Nouvelle-Calédonie. Diversité des stratégies adaptatives
Monniot, C.; Monniot, F. (1991). Tunicata: Peuplements d'ascidies profondes en Nouvelle-Calédonie. Diversité des stratégies adaptatives, in: Crosnier, A. Résultats des Campagnes MUSORSTOM 8. Mémoires du Muséum national d'Histoire naturelle. Série A, Zoologie, 151: pp. 357-448
In: Crosnier, A. (Ed.) (1991). Résultats des Campagnes MUSORSTOM 8. Mémoires du Muséum national d'Histoire naturelle. Série A, Zoologie, 151. Editions du Muséum: Paris. ISBN 2-85653-186-5. 466 pp., more
In: Mémoires du Muséum national d'Histoire naturelle. Série A, Zoologie. Editions du Muséum: Paris. ISSN 0078-9747, more
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| Authors | | Top |
- Monniot, C., more
- Monniot, F.
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| Abstract |
A survey of the bathyal and abyssal area around New Caledonia began in the South-West Pacific Ocean with some recent cruises of French research vessels. The ascidian fauna appears especially diverse, with 58 species of which 31 are new. The species described here belong to almost all genera known throughout the world showing deep-sea adaptations. The 5 main types of trophic adaptation defined for deep-sea tunicates are represented. Around New Caledonia the species having the most elaborate adaptations are more numerous than in the Antarctic, Atlantic or Indian Oceans. Some of the species may possibly be intermediates between shallow water and deep-sea genera. Some genera previously known by a small number of species are here very diverse, and provide the opportunity to discuss their affinities. This applies to the genera Pharyngodictyon (Aplousobranchia), Simla (Octacnemidae), Bathyoncus and Fungulus (Stolidobranchiata). A new interpretation of Corynascidia and Pterygascidia is proposed. With the discovery of 3 new species in New Caledonia, some evolutionary stages of the genus Molguloides (Molgulidae) may now be discussed in terms of branchial structure. A tabular key of the 13 species of this genus is presented. The bathymétrie distribution is compared here and in other oceans. The species showing morphological adaptations to the deep-sea live at higher levels in the New Caledonia area than in other oceanic basins. However the presence of deep-sea forms in relatively high levels has been established in other tropical areas (Indonesia, Philippines, Comores). The higher temperature of the water at this depth in low latitudes may have less influence on the ascidian ecology than the seasonal variations occurring in temperate and cold areas at equivalent depths. The affinities of the New Caledonian deep-sea ascidians vary with the families and the kind of adaptations but they are most closely related to the antiboreal fauna of temperate and cold areas. There is no relationship with the shallow water fauna. For the Polyclinidae, with the greatest diversity, relations are established with New Zealand and the subantarctic areas. The deep-sea phlebobranchs are principally known from the southern hemisphere. New Caledonia has the largest number of Octacnemidae species wordwide. The Styelidae dominate in the deep Atlantic but are poorly represented here. The Pyuridae appear to have expanded from both Austral and Indomalayan areas. The majority of the deep-sea species of Molguloides live in the southern hemisphere and all the shallow-water species are Austral; the genus is particularly diverse around New Caledonia. |
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