BEZY, ROBERT L. AND ROBERT C. DREWES 1985
Specific status of the East African Colubrid Snake, Psammophis tanganicus.
Journal of Herpetology 19, No. 2, pp. 246-253.
Specimens of Psammophis biseriatus differing in number of labials bordering the
orbit have been collected together at three localities in northern Kenya. When
47 P. biseriatus from eastern Africa were assigned to taxa on the basis of the
number of labials entering the orbit, 29 had three and 18 had two. These
conditions characterize the two recognized subspecies of P. biseriatus,
tanganicus and biseriatus, respectively. In addition, the two were found to
differ significantly in color pattern and numbers of temporal, ventral, and
caudal scales. Discriminant analysis using 15 ratios indicated that differences
in head shape observed at one sympatric locality are not consistent from sample
to sample. The study indicates that P. biseriatus Peters 1881 and P. tanganicus
Love-ridge 1940 are reproductively isolated.