My best guess is that this flower is from a mallow (Malvaceae) because of its bizarrely stalked reproductive parts. This was common along the banks of Rio Claro, Corcovado National Park.
These glass shrimp (I can’t recall the species) are extremely common in Osa streams, as are the Neritid snails below.
I had to take these photos from the surface, since I don’t have an underwater camera, but I think it would be extremely cool to see some underwater, macro-photography (like that over at Myrmecos) of macroinvertebrates.
Snapper (Lutjanidae – mostly Lutijanus spp.) inhabit near-ocean reaches of streams throughout Costa Rica. They are generally marine, but will often feed in freshwater and it seems that they dominate the large, fish predator group in Costa Rican streams as a result. There are at least three common species in the Osa Peninsula, where these were found, including Lutijanus novemfasciatus (the black snapper or Pacific cubera snapper). Last year, we caught L. novemfasciatus in Rio Madrigal and recorded a new species for Osa.
I’m unsure of the identification of those below, but they were photographed in Rio Claro, near the Sirena Field Station in Corcovado National Park
Traveling back from Jefferson National Forest, we stopped at Shenandoah National Park, photographing some of the breath-taking views along the ridge-top highway. A park ranger warned us of an incoming snow storm, which was expected to shut-down the park; the storm came later than predicted, so we weren’t trapped in the park, but when it did arrive, a light dusting covered the area… which was apparently the most snow received all winter… It makes me appreciate real winters.