All articles tagged with #tetrapods
A new Science study of embolomere fossils and early tetrapodomorphs finds no evidence of the tadpole larval stage in the life cycles of early land vertebrates, implying direct development (bypassing metamorphosis) was common, challenging the long-held view that amphibian-like metamorphosis aided the water-to-land transition.
A new study of well-preserved 300-million-year-old embryos from Mazon Creek shows early land-dwelling tetrapods, including embolomeres, developed directly from hatchlings without an amphibian-like metamorphosis, reshaping how vertebrates first colonized land.
New fossil hatchlings from the fin-to-limb transition era show early tetrapods lacked a metamorphosis, suggesting amphibian-style metamorphosis emerged after land colonization and that these species retained similar body plans throughout life.
Researchers describe Tanyka amnicola, a 275-million-year-old stem tetrapod known from seven to nine jawbones found in Brazil’s Pedra de Fogo Formation. The jaws are twisted with outward-facing teeth and a denticle-covered inner surface, indicating a grinding mechanism for plant matter and suggesting early herbivory among stem tetrapods. The discovery places this “living fossil” in Gondwana’s Permian ecosystems and helps fill gaps in the fossil record, though the full skeleton remains unknown and may have measured up to about 0.9 meters in length.
Paleontologists have named a new Permian tetrapod, Tanyka amnicola, from nine jaw fossils found in Brazil, notable for a bizarre twisted lower jaw and sideways denticles that suggest an early plant-based diet; the animal may have been up to about three feet long and lived in Gondwana-era lakes roughly 275 million years ago, making it a 'living fossil' in the stem tetrapod lineage.
Paleontologists at the Field Museum describe Tanyka amnicola, a 275-million-year-old stem tetrapod whose jaw is unlike any seen in early vertebrates: a twisted shape with backward-facing, denticle-covered teeth that likely ground plants. Once thought to be a deformity, the jaw appears to be an evolutionary design, suggesting an herbivorous lifestyle for this three-foot-long, salamander-like ancestor and revealing a long-surviving, now-extinct lineage. Only the jaw has been found, so the full appearance remains speculative.
Researchers have studied mudskippers to understand how the first animals to leave the oceans and wander onto shore would have had to figure out how to blink. Mudskippers are one of the few fish that can survive outside of water for extended periods of time thanks to their amphibian-like adaptations. By studying mudskippers, the researchers say that there’s an opportunity to understand how tetrapods may have evolved to blink millions of years ago in a separate yet similar way. The mudskipper appears to have rearranged its muscles in order to pop its eyes in and out, hinting that ancient tetrapods may have evolved in a similar way.
Mudskippers, an amphibious fish, have evolved a blinking behavior that serves many of the same purposes as human blinking, providing clues as to how and why blinking might have evolved during the transition to life on land in our own ancestors. The study shows that blinking may be among the suite of traits that evolved to allow the transition to life on land in tetrapods. The researchers analyzed the behavior with high-speed videos and compared the anatomy of mudskippers with that of a closely related water-bound fish that doesn't blink.