Friday, August 31, 2012

[Ornithology • 1999] Sangha Forest Robin | Stiphrornis sanghensis • Speciation in African forest robins (Stiphrornis); with a new species from the southwest Central African Republic



Adult male and Juvenile male Stiphrornis sanghensis, photographed in in Dzanga-Sangha Dense Forest Reserve, CAR, June 1998. Photograph by J. Cracraft.


Abstract
The monotypic genus Stiphrornis (Aves: Turdidae) is revised under a phylogenetic species concept to include four species, one of which, from the southwest Central African Republic, is new. Mitochondrial DNA sequence data are analyzed to explore the phylogenetic relationships within Stiphrornis. These data indicate relatively high levels of sequence divergence among the species and corroborate their recognition as diagnosable taxa, a conclusion also supported by morphological evidence. These findings, along with the allopatric distributions of the species, compel attention to their phylogenetic and spatial history, which was not explored when this group was ascribed to a single ‘‘biological’’ species.

Data reviewed here also suggest that the northwest Congo Basin forest, where the new species was discovered, is more zoogeographically complex than has been previously suspected. In addition, application of a phylogenetic species concept emphasizes the narrow endemism of S. gabonensis and S. sanghensis, along with its implications for conserving their threatened habitats.

The findings of this paper also reinforce the notion that patterns of geographic variation in the lowland forests of West and Central Africa are still incompletely understood and that the impact of environmental and geological history on the diversification of the forest avifauna has not yet been fully explored.



Fig. 4. Distributions of species of Stiphrornis (after Keith et al. (1992) and material examined in this study). Range limits of taxa in the western Congo Basin are poorly known at present, therefore it is uncertain whether parapatry exists between S. gabonensis and S. erythrothorax.


Stiphrornis e. gabonensis, Gabon Forest Robin (top) and 
Stiphrornis e. erythothorax, Western Forest Robin (bottom)
Source: Catalogue of the birds in the British Museum. Volume 7. 1883
Author: Joseph Smit (1836–1929) | http://en.wikipedia.org/wiki/File:StiphrornisSmit.jpg

Beresford, P. & Cracraft, J. 1999. Speciation in African forest robins (Stiphrornis): species limits, phylogenetic relationships, and molecular biogeography. American Museum Novitates. 3270: 1–22.

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