Observation of the Week, 7/7/17



Our Observation of the Week is this Five-toed Worm Lizard, seen in Mexico by @screws!

“I didn't seriously become interested in biology until I was in my 20s and worked at a (now closed) bookstore in Berkeley while going to community college,” says Sarah Crews. “I was in charge of shelving the science section and would read books about evolution and critters. One day I read a book called the Biology of Spiders. I hadn't thought much of spiders but after reading this book I was contacting people (via phone and letter as it was the olden days) mentioned in the book asking them how I too could study spiders.”

Her interest in spiders, and especially selenopid or flattie spiders (“I didn't know anything about them when I began and sort of hurriedly chose them from the World Spider Catalog so I could pretend I had a plan should I be accepted to Berkeley. It was probably one of the best accidental choices of my life.”) has led her to many places around the world, including several stints in Australia, where she’s described over thirty new species of selenopids. She’s now a post-doctorate at the California Academy of Sciences, working with Assistant Curator and Schlinger Chair of Arachnology Lauren Esposito.

Lauren runs the Islands and Seas Science and Surf Summer Institute with Erik Stiner, and Sarah was down there last month, teaching about terrestrial arthropods and geology. Herpetologist Sara Ruane was down there as well, and it was in the pitfall traps that she and her students had made where the Five-toed Worm Lizards were found. “They aren't uncommon - they just live underground, so unless you are looking for them, you probably won't find them,” says Sarah. “We were a bit surprised they were in the pitfalls, because they must surface briefly...They're very unique animals.” In local folklore, these lizards are thought crawl up the anuses of humans, but Sarah tells me “we assured them this isn't true and I think [that] sparked their interest to understand the uniqueness of the immediate world around them. Next year, I &S hopes to expand the program to work with the school in the town.” Due to its unique geological history (it’s been separated from mainland Mexico for 10-12 million years), Baja California has many endemic species. “It's a really wonderful place and I encourage everyone to go if they have the opportunity,” says Sarah. “I've been there a lot and there are still many places I want to explore there. Also, selenopids live there which means it's a great place!”

Sarah’s not kidding about the uniqueness of the Five-toed Worm Lizard. It’s one of only three species in the genus Bipes (the others, of course, being the three-toed and four-toed varieties), and they’re the only extant members of the worm lizard family (Amphisbaenia) with legs. As Sarah said, these reptiles (which are neither snakes nor lizards) spend most of their time underground, using their forelimbs to build tunnels in the soil as they look for invertebrate prey. And while they resemble snakes, the Amphisbaenia are most closely related to the wall lizards, so they developed their legless bodies entirely separately from snakes (which are believed to have evolved from lizards).

Now that she’s working at a the Cal Academy, Sarah doesn’t have as much time for iNat as she used to, but she still uses it to post observations from her field work and to look for new selenopid locales, like this one found in Borneo, a probable new species. “I like helping people learn new things and when they get excited about seeing something they haven't seen before (like Bipes) or when I get excited about seeing something I haven't seen before.”


- by Tony Iwane

- Of course there’s a video of the worm lizard!

- Check out Sarah’s publications here, and follow her on Twitter!

- Some selenopid spiders fly! (Well, glide)

Posted by tiwane tiwane, July 08, 2017 01:48 AM

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