PAUL HERTZ (MCZ), while participating in the summer 1973 OTS course, 
was able to study the thermal biology of a mainland anole, Anolis polylepis. 
This forest species appears to be passive to environmental temperature 
(at least during the rainy season) and neither actively basks nor actively 
takes refuge from the sun. It nevertheless does maintain body temperatures 
that on the average are about two degrees above air temperatures. These 
results parallel Huey's data on cristatellus in forest in Puerto Rico and 
support the Huey-Slatkin model of lizard thermoregulation. 
Hertz also observed that A. polylepis seemed to be more numerous in 
the small areas of denser vegetation resulting from minor disturbances in 
the forest, It was not clear what factors might be involved, Possible 
are higher air temperatures, higher local productivity etc. He hopes to 
return to Costa Rica in the near future to study polylepis' utilization of 
habitat patches, 
Hertz, in addition, has been investigating the relationships and status 
of Anolis cochranae, Described as a full species, it has been variously 
suggested that it is a subspecies of A. semilineatus or a high altitude 
population of the latter only clinally distinct in scale size from surrounding 
lowland populations. A search has been made for any characters other than 
scale size that might distinguish cochranae, No constant external characters 
have been found, but electrophoretic studies are now under way in collabo- 
ration with T, P. Webster. At the moment these suggest that A. cochranae 
is not a species but only an altitudinal phenotype of A. semilineatus. 
Topotypic animals from Constanza are, at all events, not as different from 
white-dewlapped populations called A. semilineatus as is A. olssoni. 
There is evident considerable inter-population difference within what is 
called semilineatus (e.g. the major difference may be between south island 
and north island populations and not between altitudinally separated 
populations on the north island), Samples, however, have been small and 
not from localities best fitted to solve the evident problems. It is very 
clear that large new collections need to be made and that these need to be 
from places chosen very carefully. 
Hertz hopes to find similar clines in other widely distributed Hispaniolan 
anoles. If patterns comparable to those found in the semilineatus complex 
are evident in other species, he hopes to develop a general model of the 
effect of altitude on scale and body sizes, The work must obviously consider 
the effects of competitive release and possible niche expansion as various 
species encounter different combinations of congeners along altitudinal 
transects, 
