We chose as an important site to visit on this jumping spider expedition the summit of highway 175 as it goes north from Oaxaca City. There, at about 3000 metres elevation in a place called “Humo Chico”, is a foggy, damp elfin forest. In 1983 on my first trip to Mexico, I caught some elegant little jumping spiders there. Uriel named them “diamond” after the shapes of their markings. We can see that they are generally related to Mexigonus, but it’s not clear to us that they are actually Mexigonus, as they are more delicate-bodied than the other Mexigonus species we know. If they are Mexigonus, they would show the genus can evolve to such a body form, and so they are important for Uriel’s project. Their other point of interest is that two colours of males were found in 1983: one with the first two pairs of legs black, the other with just one pair of legs black. With fresh specimens, we could get new data to decide if they were Mexigonus, and whether the two forms represented different species.
We drove up on Monday from Ixtlán to this high elevation site, but it was misty, raining. We went first to the microwave station at the top, and found very little. All of us were discouraged. We decided to walk down to the main highway. I’m accustomed to jumping spider species staying hidden in their retreats, and so I expected that my anticipation in seeing these delicate spiders would be unrewarded.
And then a surprise occurred. In the drizzle, a jumping spider dropped on my beating sheet that I didn’t recognize at all. Pale and with long legs, it looked ghostly. When I picked it up in the vial I saw that it was a male with a big white moustache, and little black tips to the first legs. Beneath its white hairs the legs were a soft green colour. No jumping spider like this very distinctive species has ever been described. Here is the beautiful male staring boldly at my camera:
Here are a male and female from above:
We ended up finding 9 males and a few females of the green ghost Mexigonus. Even though I enjoy finding new species of any sort, whether brown and dull or spectacular, I have to admit that strange and colourful species excite me the most. Finding green ghost was a special moment.
But we didn’t find any “diamond” on our walk down to the highway. I was prepared to give up.