Subspecific Variation in the Redcrested Korhaan Eupodotis.Pdf
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VOL. XI, PART 12 ISSUED 30th SEPTEMBER, 1977 MISCELLANEOUS TAXONOMIC NOTES ON AFRICAN BIRDS XLIX b y P. A. CLANCEY (Director, Durban M useum, Durban) SUBSPECIFIC VARIATION IN THE REDCRESTED K O R H A A N EUPODOTIS (LOPHOTIS) RUFICRISTA (SM ITH ), 1836 The small Redcrested Korhaan or Bustard Eupodotis (Lophotis) ruficrista was described by Dr. Andrew Smith in his Report of the Expedition for Exploring Central Africa, 1836, p. 56, where it is stated to inhabit the country between Latakoo (Kuru m an) and the T ropic of Capricorn. In his Illustrations o f the Zoology o f South Africa, Aves, 1838, pi. iv (and text), the collecting local ity is m ore precisely given by the author, when Sm ith states that the “sp ecies w as first discovered in the vicinity of Latakoo,” which m ay b e accepted as the type-locality. The Redcrested Korhaan is freque ntly considered to be conspecific with two northern Ethiopian Afric an bustards: Eupodotis (L .) gindiana Oustalet, 1881: between Som aliland and Zanzibar, East A frica=B ardera, Giuba R ., south-west ern Som alia, according to M ackworth-Praed and Grant, Birds Eastern and North Eastern Africa, vol. i, 1952, p. 323, send Eupodotis (L .) savilei L y n e s , 1920: En Nahud, western K ordofan, Sudan, though Scl a t e r , Syst.Av. Aethiop., part i, 1924, p. 115, treats ruficrista, gindiana a n d savilei a s three separate species, w hich latter arrangem ent ap pears to be nearer the truth of the m atter. The north-eastern gindiana differs in the adult m ale in lacking the leaden streak below the eye, in being paler and m or e cream y, less bluish grey, over the sides of the neck, and on the breast the w hite is [Price R 1,00 nett] Reproduced bySabinet Gateway under licence granted by thePublisher (dated .) 2 2 4 Miscellaneous Taxonomic Notes on African Birds m ore extensive. The black of the throat is extended dow n the centre of the low er fore-throat and m id-breast to link up with the black ven tral surface, narrow ly sundering the pectoral white . The crest is also m arkedly paler, m ore buffy (hence the vernacular na m e Buffcrested Bustard), less vinous than in ruficrista. The dorsum further exhibits m arkedly reduced cream -coloured sagittate markings, appearing m ore uniform , and in the wings the remiges have the inner vanes extensively pale greenish yellow, form ing a pale ye llow patch over the ventral w ing when closed. In ruficrista this surface appears black. The north-western savilei is m ore rufous-sandy above than gindiana, the black over the throat in m ales not extending ca udad to the lower fore-throat and breast, and the white on the breast again restricted laterally as in ruficrista, which it also resem bles in the m ale having a grey sm udge-m ark below the eye. Bannerman, Birds of Tropical West Africa, vol. ii, 1931, p. 62, gives wings of savilei a s 243 - 257, 9? 240 - 246mm in ten measured, these me asurem ents sm aller than in the austral ruficrista. T h e f o r m s savilei a n d gindiana (with its second race E.(L.) g.hilgerti (Neum ann), 1907: Dabab, nor thern Som alia), while probably not in contact in th e southern Sudan, are still not spatially rem ote in this region of no rth-eastern A frica. They m ay be considered a parapatric pair of allospe cies rather than being treated as conspecific at this stage in our u nderstanding of the relationships of the small African bustards of the sub-genus Lophotis Reichenbach, 1848. As for the southern African Redcrested K orhaan, I c an see no ad vantage in associating this form with gindiana a n d savilei o w i n g t o the wide range of characters separating the adult m ales and the ex tensive geographical gap between it and the tw o lat ter taxa. The southern populations of gindiana reach as far south as east-central Tanzania according to M ackworth-Praed and Grant, loc.cit., w h i l e ruficrista ranges no further north-east than south-w estern and s o u t h ern Zam bia and about the Gorongosa National Park in s o u t h e r n M o 5a m b i q u e . E.(L.) ruficrista is distributed from south-western and southern Angola and South W est Africa, east to south-western and southern Zam bia, Rhodesia, southern M o 5am bique, the Transvaal north of the highveld, Botswana, the northern Cape, eastern Swaziland, and eastern Zululand. It affects lightly to m oderately densely wooded savanna with a good grass understorey, and, while q uite num erous in som e localities, tends to be highly local. A t no tim e has it been suggested that the populations show anything in the nature of sub- specifically significant variation. A recent study reveals, however, that the accepted uniform ity of the populations is an illusion, and Reproduced bySabinet Gateway under licence granted by thePublisher (dated .) by P . A . Clancey 2 2 5 that in com m on w ith m any other birds whose ranges e xtend from the xeric west of the South African Sub-Region to the m esic south eastern coastal lowlands, the Redcrested Korhaan ca n be arranged in tw o subspecies, based on variation in the colour ation of the upper- p a r t s . The xeric western populations of ruficrista, extending probably from south-western Angola, but certainly from the K a o k o - veld, south to northern and eastern Great Nam aquala n d , S o u t h W est Africa, the western Kalahari in Botswana, and the north-west of the northern Cape differ at above the accepted l evel of discrim ina tion for subspecies from the populations occurring to the north-east and east in having the m antle, scapulars, tertials and adjacent wing- surfaces redder, m ore ochraceous-rusty, less dull e arthen or stone- coloured. Such a pattern of colour variation is com m on to m any plas tic species w ith com parable distributions in the dr y interior and far west of the South African Sub-Region. A short series of ruficrista from Kurum an, the type-locality, shows that the tw o facies m eet in this district of the no rthern Cape. O f four from Kuruman in the collection of the Durban Museum , o n e r e sem bles the reddish backed western elem ent, the oth ers the eastern populations, w ith w hich latter, acting as first rev iser, I here form ally associate the nom inate subspecies. Study of the ori ginal description of Sm ith’s Otis ruficrista of 1836 at first suggested that the name m ight be m ore accurately assigned to the reddish ba cked western population, but the coloured figure by the artist G eorge Ford in S m i t h ’ s Illustrations (pi. iv of 1838) is clearly of the duller, m ore earthen brown, backed eastern populations, which ar e treated as the nom inate subspecies in the following arrangem en t of this sou thern African bustard: (a) Eupodotis (Lopliotis) ruficrista ochrofacies, s u b s p . n o v . T ype: 3 , adult. 109,5km from Stam prietfontein to D ordabis, c e n tral South W est A frica. 3 M ay, 1959. Collected on T ransvaal M useum N am ib E xpedition, 1959. In the collection of the Tr ansvaal M useum , T.M .Reg.N o. 29 806. Diagnosis: Differs from nom inate ruficrista, as defined below , in the adult fem ale having the fore-throat and breast more washed with warm buffy (deep Pinkish Buff (pi. xxix)) in n ewly m oulted condition, and taxonom ically in both sexes having t he ground to the dorsum and adjacent wing-surfaces paler and m or e ochraceous- rusty, less dull earthen or stone-coloured (Cinnamo n (Ridgway (1912), pi. xxix), versus dull Saccardo's U m ber (sam e pi-)), the dark Reproduced bySabinet Gateway under licence granted by thePublisher (dated .) 2 2 6 Miscellaneous Taxonomic Notes on African Birds m edian surfaces to the pale buffy sagittate shaft-s treaking and ver- m iculations also rather lighter and redder brow n. R um p, upper tail- coverts and rectrices with rather coarser transvers e verm iculations on a lighter ground. Sim ilar ventrally and in size. The juvenile does not differ. Measurements: W ings in 6 adult 264 - 272 (266,5), SD 3,50, culm ens from base 42 - 47,5 (45,0), SD 2,47, tarsi (approx.) 74 - 92 (85,2), SD 6,13, tails 140 - 148 (144,0), SD 3,03, wings of 4 $$ 248 - 256 (250,7), SD 3,59, culm ens 42 - 49 (44,7), SD 2, 99, tarsi (approx.) 73 - 86,5 (77,3), SD 6,16, tails 129 - 135 (133,2), SD 2,87m m . Material examined: 1 0 (northern Cape: K u r u m a n ; south-western Botswana: 96,5km N. of Boshu Bohulu Pan, 29km E. of Tshane; South West Africa: 109,5km Stam prietfontein - D ordabis, near Otji- warongo, W arm quelle, Ohopoho). Range: Northern Cape west of 23° E., western Kalahari Dese r t in Botsw ana (west of 23° E .), South W est Africa, we st and south of the Etosha Pan, north to the Kaokoveld.