With the new school year now well underway, it’s time to catch up on the latest news in animal discoveries. In keeping with the theme of some of my previous posts, I’d like to present a brief overview of a few recent findings on creatures that I find interesting.
Fish with Fingers—Almost!
Scientists have discovered an ancient fish fossil that suggests “primitive fish and sharks had the genes necessary to develop digits” even if they did not grow such appendages themselves. According to Swedish paleontologist Per Ahlberg, this is important because it means that the “precursors” to the bones of hands and feet have a very early origin. Thus, he states, the idea that such limbs were “a complete novelty that appeared out of nowhere … can now pretty much be dismissed.” Medical x-rays taken of the fossilized fish Panderichthys, which lived about 385 million years ago, show that it had “many of the same bones that make up a modern human arm” as well as fingerlike bones that “were concealed in the fleshy arm-like base of its fin.” These fingerlike parts later emerged when fins evolved into the limbs of the earliest tetrapods, the amphibians (our next topic).
Frogs That Have Been Found—Again!
Australia: Throughout the world, a chytrid fungus is being blamed for wiping out numerous frog populations. One such population, thought to be extinct, was that of the Armoured Mistfrog, of Queensland, Australia. The tiny frog, which is currently classified as critically endangered, had not been seen since 1991. But just a few months ago, a doctoral student who was researching frog species came across several Mistfrogs in a Queensland creek. DNA studies carried out on tissue samples from the rediscovered frogs confirmed that they were in fact Mistfrogs. In Queensland alone, seven frog species have been killed off by the fungus. So scientists are now hopeful that other rare frog species may still survive like the Mistfrogs, which are infected but not killed by the fungus. They are studying them to determine how they survive, so they can protect other frog species.
Costa Rica: Another critically endangered frog species thought to be wiped out by the chytrid fungus was recently rediscovered in the Monteverde Cloud Forest Preserve of Costa Rica. The tiny tree frog, called Isthmohyla rivulas, had not been seen for 20 years. Then, just last year, a researcher from the University of Manchester spotted a male of the species. Although this was a good sign, it was not enough to believe that the population was recovering. So, a team from the University returned to the remote spot in the forest where the male had been seen to look for more specimens. They first spotted another male of the species because it was making its soft mating call. Then they looked deeper in the foliage and spotted a tiny female, full of eggs, that was sitting on a leaf. Finding a female frog gave the scientists great hope that there is still a viable breeding population. A bonus to the expedition was that a BBC film crew that went with them was lucky enough to capture the first footage of this extremely rare tree frog.
Found in Fiji—Iguana Be Happy!
Known for their great beauty and geographical isolation, the Fiji Islands lay in the middle of the Pacific Ocean. Also known for their beauty and ecological isolation are the few species of iguanas that inhabit the Fiji Islands. One surprise is that the closest relatives of the Fijian iguanas are found in the Americas (nearly 5000 miles away). The ancestors of the Pacific lizards probably rafted to the Fiji Islands over 10 million years ago on mats of floating vegetation. Another surprise is that a new species has just been found on the Fiji Islands. Named Brachylophus bulabula, this new iguana is one of three Pacific iguana species that is still alive. The two other species are either rare or critically endangered, due to habitat loss and feral animals, such as cats, mongooses, and goats, which eat the lizards or their food. Two other species became extinct after people arrived on the islands a few thousand years ago and decided the lizards made a good meal. Now that a new Fijian iguana has been identified, scientists are working to better understand the ecology of these lizards so that they can be better protected against climate change and habitat loss.
