Denes et al. • LEPTODON FORBESI IS A VALID SPECIES 
325 
forbesi, and we complemented the analysis with 
data taken in the field because this taxon is 
critically endangered (Birdlife International 
2000 ). 
We examined the distribution of L cayanensis 
for discontinuities in characters along its geo¬ 
graphic distribution and with L. forbesi. The 
subspecies described by Swann (1922) and taxa 
considered by Hellmayr and Conover (1949) may 
be considered valid if at least one character does 
not overlap between populations (evidence of 
lineage divergence). 
Morphometry .—We measured: beak length 
(from the tip to the rostral edge of the cere), 
width (measured at the rostral edge of the cere), 
wing (chord), tail length, and length (measured at 
3 places at the middle of each vane and at the 
rachis) of the distal white and black tail bands, 
both dorsnlly and ventrally. We used analysis of 
variance (ANOVA) to compare morphological 
measurements among subspecies based on spec¬ 
imen locality. We used only adult male specimens 
to avoid possible complications due to sexual 
dimorphism and development, and analyzed only 
specimens with information describing collecting 
location. Coordinates, when absent, were obtained 
troin maps. We used regression analysis to test for 
latitudinal trends in body size. 
RESULTS AND DISCUSSION 
Examination of Museum Specimens .—A spec¬ 
imen (M2USP 38922) of the While-necked Hawk 
'Lt'ucnptenris lacernulatus) collected in 1957 in a 
forest fragment at Usina Sinimbu, southeastern 
Alagoas (Pinto and Camargo 1961) was recog¬ 
nized as a representative of genus Leptodon. 
Generic identification was based on tail and tarsi 
''ize and proportion, and morphology of the beak. 
The bird agrees well with the holotype of L. 
f° f besi in all characters traditionally recognized, 
including the whitish hind collar, white lips on 
mantle feathers, scapulars, secondaries, and inner 
Primaries, a single broad ashy-white band on the 
'ail. and white underwing coverts. It has a white 
leading edge of the wings and two waves of 
Primary molt indicating it is an adult (Edelstam 
19 K Clark 2004). This specimen is now 
'dentified as L. forbesi. Recent raptor surveys 
foiled to detect L. lacernulatus in the states of 
Alagoas and Pernambuco (Silveira et al. 2003, 
- Sei Pke et al. 2011). 
Variability in Leptodon cayanensis .—Analysis 
(he 71 adult Leptodon cayanensis specimens 
FIG. I. The relation between body size and latitude in 
Leptodon cayanensis subspecies. 
ranging from Mexico through Central America to 
southern Brazil and Bolivia revealed no color 
differences to support the subspecies described by 
Swann (1922). Characters supposedly diagnostic 
for each subspecies were found on specimens of 
different subspecies. 
Morphometry. —Wing length of Leptodon 
cayanensis was more strongly associated with 
latitude (r = 0.38, F U65 = 41.4. P < 0.05) than 
was tail length ( r 2 - 0.28, F^ 65 = 27.2, P < 
0.05; Fig. 1). The residuals for wing length and 
tail length were similar among all subspecies 
(F 2 ,6 i = 2.72. P > 0.05 and F 2 .b\ = 0.17, P > 
0.05. respectively) when controlling for this 
latitudinal cline. There was no relation with 
latitude in beak measurements (culmen and 
w idth) (both P > 0.10). Measurements of these 
characters were similar among all putative 
subspecies (all P > 0.10) and provide no support 
for separation of subspecies. 
Distal tail bands, both black and while, were 
variable among the putative subspecies, while 
the white tail bands of L. forbesi were greater 
(56-57 mm) in width. The sample size for L. 
forbesi was small, and we described only the 
comparisons between the putative subspecies. 
