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Lieferstatus:	i.d.R. innert 5-10 Tagen versandfertig
Veröffentlichung:	Januar 1999
Genre:	Naturwissensch., Medizin, Technik
ISBN:	9783540649960
EAN-Code:	9783540649960
Verlag:	Springer Berlin Heidelberg
Einband:	Kartoniert
Sprache:	English
Dimensionen:	H 235 mm / B 155 mm / D 9 mm
Gewicht:	248 gr
Seiten:	156
Zus. Info:	Paperback
Bewertung:	Titel bewerten / Meinung schreiben

Inhalt:

Morphogeny of the nasal skull was investigated in 92 embryos of 13 species of Cetacea. Compared to the original nasal capsule of land mammals, the nasal structures of Cetacea show many weighty transformations. As a result, the nostrils are translocated from the tip of the snout to the vertex of the head. Several structures of the embryonic nasal skull remain preserved even in adult cetaceans. The translocation of the nostrils to the highest point of the surfacing body is among the most perfect adaptations of cetaceans to the aquatic life habits. The morphogeny of the nasal skull suggests that all cetaceans are of common origin and form a single monophyletic order. The hitherto usual division of this order into two suborders, Mysticeti and Odontoceti, appears to be unsubstantiated. Rather, at least three closely related superfamilies should be distinguished within the order Cetacea, viz., Balaenopteroidea, Physeteroidea, and Delphinoidea. The results are in a TOC:Introduction.- Material and methods.- Synopsis of structures of the embryonic nasal skull.- Morphogeny of the nasal skull.- Metamorphosis and translocation of the nasal structures.- Comparison of the embryonic nasal structures.- The Nasal structures of adult Cetacea.- Evolutional and functional relationships.- The systematics of Cetacea according to the morphogeny of their nasal skull.- Summary.- Acknowledgements.- References.- Subject index.- Abbreviations.