Greene, H. 1980 6 December (continued) some impressions so far. Lizard biomass must be very high in some parts of the Sechura Desert, on the basis of Dicrodon guttulatum - I saw up to 4 under a small tree, and conservatively, 20 under a "bush" with a diameter of 10m - there might have been several times that many. Plus Phyllodactylus, Tropidurus , and the occasional Colopistes. My impression was that there were many more juveniles, females (and subadult males?) than there were large adult males - those with the brightest blues and reds on the foreparts. It may have been the case that there was one such male/large group of "others" - but I'm uncertain and it might be very difficult to study this. Several times I saw a Dicrodon travel fairly fast (but not at escape speed) across an open space and then go down a burrow - as if it knew the location very precisely. as I probably mentioned earlier, these lizards hand wave extremely frequently, especially just after moving. The two species of Tropidurus I saw at Cerro la Vieja were very reminiscent of Sceloporus - occidentalis or an undulatus or an