Saurian Expedition Turns Up Mystery Lizard

I had been told a few years back that our area had a disjunct population of Western Fence lizards, but had never seen them. I grew up with "bluebellies" in the Los Angeles area, and missed having them around. Actually, I had lived in Port Townsend, Washington for thirteen years, and had yet to see a lizard there. So, when a visit I made for work ended up in a conversation about the local lizards, I became very interested. The owner of a piece of property on the East-facing bluff of Discovery Bay assured me that the lizards were there in great numbers. He went into the house, and came out with a beautiful specimen of sceloporus occidentalis, which he said his son had caught and was keeping in a terrarium. He told me that I was welcome to come back another time to photograph the lizards.

The property is on a steep slope that drops 100 feet or more to Discovery Bay. Some quirk of geography has created a microclimate here where the lizards thrive, along with Prickly Pear cactus that exists nowhere else in the area.

The key to the lizards' survival seems to be the dry fallen trees, which are infested with ants. While it took about fifteen minutes for me to start finding lizards, once I did, it was obvious that they congregate around these trees, which provide both food and shelter.

The first lizard I saw was sitting motionless in a patch of grass near one of the fallen trees. This lizard was clearly s. occidentalis or some subvarietal, but was grey in color, with the exception of the tail. I photographed it but was unable to catch it. The next lizard was found on a tree which proved to be a treasure trove. I captured this one easily, and verified by flipping it over, that it did indeed have the blue ventral surface that I had come to expect.

The surprise came a few minutes later, when I spotted another lizard peering out from underneath a layer of bark. This lizard had the yellow striped tail of s. occidentalis, but was otherwise quite different. The dorsal scales were black, and the ventral surface was an eggshell white with black speckling. I tried for some time to catch this specimen, but was unable, and I settled for taking two photographs. This lizard does not appear to be either of the two species we are reported to have in the area - either sceloporous occidentalis or Gerrhonotus coeruleus, the northern alligator lizard (shown below on a tree, photographed on the same day.)

It seems unlikely that such a small population would have such an abundance of different color morphs. I wonder if perhaps this black fellow is an unrecognized species, or possibly an existing species that was not formerly known in this area. I hope to return to the area to find and hopefully collect more specimens to be able to verify this lizard's identity. Until then, it remains a mystery.