These elateridae larvae roam moss-covered boulders and banks of the streams in Las Cruces, mandibles wide-open and hunting prey. Not pictured, because I don’t have an appropriate camera with shutter control, is their glow. If you’re in the stream at night and turn off your headlamp, you’ll soon notice small green “stars” lining the banks—hundreds of them. These guys are bioluminescent!
Two common, stream-side spiders at Las Cruces. Trechalea extensa is large and hangs out on boulders, dangling it’s fore-legs in the water at night to potentially attract prey, such as small fish. Patricia Esquete’s student’s, Neola and now Macy, have been studying their ecology the past couple of years.
The other spider, probably a nursery web spider (Pisauridae) like this one from Palo Verde, creates a silken tether on a branch and dangles from it, skating on the moving stream surface and likely capturing floating prey as it moves downstream.
I’ve found these wax mallows (Malvaceae, Malvaviscus spp.) in both Savannah and Costa Rica. The species’ range of M. arboreus – the likely Georgia resident – extends into South America, but there is an endemic to Costa Rica — M. palmanus. The specimen from Las Alturas has pubescent stems and sepals, but I’m not sure if this is characteristic.
To some degree, I have been working with crabs at Las Cruces since 2013, and I have identified only a handful of males using various keys (the latest by Magalhaus et al 2015). This year, I aimed to identify all the crabs we caught and studied if we could, so Gabby, Juliet and I sat down to identify two males, randomly chosen from a set we had discovered trematode metacercariae in, using the key.
As we slowly moved through the key towards Allacanthos pittieri which I had previously identifed in other summers and a few days earlier as a brush up, Gabby expressed some skepticism and challenged my guidance through the key. I dismissed her concerns to some degree (and I hope she’ll forgive me) as we worked through defining the terms in the first couplet, but eventually had a look at her crab’s gonapods (the structures used to transfer sperm in decapods and commonly used to identify them to species). I immediately and excitedly knew she had something else.
The three of us spent the rest of the day keying the new crab and confirming the identity of the other, and it was glorious. There is nothing cooler than working with engaged, enthusiastic, and smart students… especially on something as cool as a second crab species!
While I think we stumbled on a couplet (11) and eventually mis-identified the crab as Ptychophallus montanus, I think we’re confident that the other species of crab is P. paraxanthusi. At this point, we’re working on markers of the crab that don’t involve microscopy and allow us to identify the females.