Quest for a tidal spider

In my last blog post I described my somewhat obsessive quest to find the mysterious green-faced Habronattus of southern Arizona. It’s not my only such quest. Another that comes to mind was spent mostly waiting — for the chance to return Sonora to look for the strange tidal spider of the Sea of Cortez.

On the northernmost shore of México’s Sea of Cortez is a little town called Puerto Peñasco. The land there is a harsh, harsh desert, with sparse vegetation barely hanging on. The sea, though, is beautiful, and rich with life. Where they meet, the land blooms. The fluctuation of the tides has eroded inlets that are called “negative estuaries”, mud flats with river-like channels where the tides drain. These mud flats are covered with plants like Salicornia that are tolerant of salt water.

In 2003 I visited one of these negative estuaries, and found a male Habronattus jumping spider that I thought was immature, because it lacked the usual fancy colourful ornaments typical for adult male Habronattus. But a closer look showed it to be adult, a rather peculiar one, unlike anything I’d seen. When I got it back to the lab, I was confused by its features. Some of its traits suggested that it belonged to one group of species; others suggested it belonged to another group. Was it a hybrid? Did it occupy a special place on the evolutionary tree?

I called it “the Peñasco beast”. My curiosity was strong, but I didn’t get a chance to get back to look for more until 10 years later. Our little 2013 expedition, consisting of Heather Proctor, Geneviève Leduc-Robert, Sam Evans and me, arrived to Puerto Peñasco after the drive from Tucson. We were staying and working at CEDO (Centro Intercultural Estudios Desiertos y Oceanos), a scientific and educational centre that plays many roles in raising knowledge and awareness about the amazing ecosystems there. The estuary was close by, so every day we went to look for the Peñasco beast.

What we found, instead, was a different species of Habronattus that was quite striking: a little yellow-orange “monkey” with green legs and a stunning red face, hopping from plant to plant. It was common, and yet it was another new species, never before collected. Exciting, but where was the Peñasco beast? We found but a single baby, and nothing more.

The morning came when we were to pack up and leave. I was pretty disappointed. My colleagues offered to pack up, and urged me to go out one last time to look. So, I went out with our local guide Abraham Meza López to a new spot, a bit of a drive away. The habitat at the other estuary was a bit different. I found a female! And another! And a male! I was beside myself with joy, but at the same time, anxious. We were already late returning to CEDO, and I still wanted to look for more. I knew that the crew would be worried as to why we were late, and might be imagining bad things happening to us in the unfamiliar estuary. But how to tell them not to worry? We were in the middle of this desolate estuary, probably a few kilometers from the nearest human. I knew that none of my colleagues would have their Canadian or American cell phones turned on. But, I knew that they had computers, and internet access at CEDO, and they were probably bored (but anxious) waiting for me. So, I turned my cell phone on — signal! — and sent a tweet that we’d found the Peñasco beast. When I got back I was greeted with congratulatory hugs, rather than cries of relief, and so I knew they’d seen the tweet. And we had the Peñasco beast again!

Habronattus aestus and its habitat in the negative estuaries of Sonora

Habronattus aestus and its habitat in the negative estuaries of Sonora

The specimens we got in 2013 helped me to prepare the publication describing it as a new species, Habronattus aestus. The specimens were also used in a genetic analysis that found it to be a cousin of some species found around my haunts here in Vancouver (Habronattus americanus and Habronattus ophrys). Even when you travel far away, you find things with genetic ties to home.

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