The species exhibits sexual dimorphism in size. Males are larger, measuring 38 cm (15 in) in length and weighing 340–635 g (12.0–22.4 oz), whereas females measure 33 cm (13 in) in length and weigh 340–549 g (12.0–19.4 oz). The species has barred underparts (in contrast to the related Natal spurfowl) and a conspicuous yellow eye-ring.[2]
Taxonomy
The red-billed spurfowl was described in 1838 by the English naturalist George Robert Waterhouse from specimens collected by James Edward Alexander on his expedition to Namaqualand and Damaraland. Waterhouse coined the binomial nameFrancolinus adspersus and noted that the specimens had come near the Fish River in what is now Namibia.[3] The specific epithet adspersus is Latin for "sprinkling".[4] The species is now placed in the genusPternistis that was introduced by the German naturalist Johann Georg Wagler in 1832.[5][6] The red-billed spurfowl is considered as monotypic: the proposed subspeciesmesicus is not recognised.[6]
^McGowan, P.J.K. & Kirwan, G.M. (2017). Red-billed Francolin (Pternistis adspersus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/53412 on 22 May 2017).
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