turaco n : large brightly crested bird of Africa [syn: touraco, turacou, turakoo]

The turacos, plantain-eaters and go-away-birds make up the bird family Musophagidae (literally "banana-eaters"). In southern Africa both turacos and go-away-birds are commonly known as louries. They are semi-zygodactylous - the fourth (outer) toe can be switched back and forth. The second and third toes, which always point forward, are conjoined in some species. Musophagidae often have prominent crests and long tails; the turacos are noted for peculiar and quite unique pigments giving them their bright green and red feathers.

Traditionally, this group has been allied with the cuckoos in the order Cuculiformes, but the Sibley-Ahlquist taxonomy raises this group to a full order Musophagiformes. They have been proposed to link the mysterious Hoatzin to the other living birds but this was later disputed.

Ecology and behavior

Musophagidae are medium-sized arboreal birds endemic to sub-Saharan Africa, where thay live in forests, woodland and savanna. Their flight is weak, but they run quickly through the tree canopy. They feed mostly on fruits and to a lesser extent on leaves, buds, and flowers, occasionally taking small insects, snails, and slugs Contrary to what the names might suggest, they generally do not eat bananas or plantains and indeed wild-living Musophagidae do not seem to use Musa as food at all. The Musophagidae build large stick nests in trees, and lay 2 or 3 eggs.

Go-away-birds are noted for their piercing alarm calls, which alert other fauna to the presence of predators or hunters; their common name refers to this.

Coloration

The Go-away-birds and plantain-eaters are mainly grey and white. The turacos on the other hand are brightly coloured birds, usually blue, green or purple. The green color in turacos comes from turacoverdin, the only true green pigment in birds known to date. Other "greens" in bird colors result from a yellow pigment such as some carotenoid, combined with the prismatic physical structure of the feather itself which scatters the light in a particular way and giving a blue color. Turaco wings contain the red pigment turacin, unlike in other birds where red color is due to carotenoids. Both pigments are derived from porphyrins and only known from the Musophagidae at present, but especially the little-researched turacoverdin might have relatives in other birds.

Evolution and systematics

The fossil genus Veflintornis is known from the Middle Miocene of Grive-Saint-Alban (France). It was established as Apopempsis by Pierce Brodkorb in 1971, but this is preoccupied by Schenkling's 1903 use of the name for some beetles. "Apopempsis" africanus (Early Miocene of Kenya) might also belong there.

Further fossil material of putative musophagids was found in Egypt as well as in Late Oligocene deposits at at Gaimersheim (Germany) and Middle Miocene deposits at Grive-Saint-Alban and Vieux-Collonges (both France). While it is not entirely certain that these fossils indeed are of turacos, it nonetheless appears as if the family evolved in the Oligocene of central Europe or perhaps northern Africa, and later on shifted its distribution southwards. The climate of those European regions during the late Paleogene was not too dissimilar to that of (sub)tropical Africa today; the Saharan desert was not yet present and the distance across the Mediterranean was not much more than what it is today. Thus such a move south may well have been a very slow and gradual shifting of a large and continuous range.

The Early Eocene Promusophaga was initially believed to be the oldest record of the turacos; it was eventually reconsidered a distant relative of the ostrich and is now in the ratite family Lithornithidae. Filholornis from the Late Eocene or Early Oligocene of France is occasionally considered a musophagid, but its relationships have always been disputed. It is not often considered a turaco anymore in more recent times and has been synonymized with the presumed gruiform Talantatos, though it is not certain whether this will become widely accepted.

The living genera of Musophagidae, arranged in taxonomic sequence, are:

• Tauraco - green turacos (14 species)
• Ruwenzorornis - Ruwenzori Turaco
• Musophaga - blue turacos (2 species)
• Corythaixoides - go-away-birds (3 species)
• Crinifer - plantain-eaters (2 species)
• Corythaeola - Great Blue Turaco

Footnotes

References

• (1969): Les Oiseaux miocènes de la Grive-Saint-Alban (Isère) [The Miocene birds of Grive-Saint-Alban (Isère)]. Geobios 2: 157-204. [French with English abstract] (HTML abstract)
• (2002): Cenozoic Birds of the World, Part 1: Europe. Ninox Press, Prague. ISBN 80-901105-3-8 PDF fulltext
• (1999): Phylogenetic relationships of the enigmatic hoatzin (Opisthocomus hoazin) resolved using mitochondrial and nuclear gene sequences. Molecular Biology and Evolution 16(9): 1300-1307. PDF fulltext
• (2003): More Taxa, More Characters: The Hoatzin Problem is Still Unresolved. Molecular Biology and Evolution 20(9): 1484-1499. PDF fulltext Supplementary Material

External links

• International Touraco Society
• Turaco videos on the Internet Bird Collection