Reference: “Fossil eggshells from the Early Cretaceous Okurodani Formation, northern central Japan” by Rina Uematsu, Kohei Tanaka, Shohei Kozu, Shinji Isaji and Shizuo Shimojima, 24 November 2022, Historical Biology. Together, these findings illustrate the value of even tiny, fragmentary eggshells in reconstructing ancient ecosystems, especially the presence of smaller animals that may be underrepresented in the skeletal fossil record. The turtle eggshells reveal the presence of small-sized non-marine turtles that can be ascribed to previously recognized skeletal remains from the strata where they were found. The discovery of small maniraptoran eggs of this age in Japan also extends the temporal and geographic ranges of these small, non-avian theropods to the middle of the Early Cretaceous of the eastern margin of Asia.” As first author Rina Uematsu explains, “Based on the dimensions of the egg fragments, we calculated that the adults of the maniraptoran species that laid them would have weighed about 12 to 17 kilograms. Our analysis suggests an affinity with the troodontids, a group of small non-avian theropod dinosaurs.”įossils of the small raptor that laid the eggs have not yet been discovered in the Lower Cretaceous strata that yielded these fossils. According to study co-author Professor Kohei Tanaka, “The shell fragments of Ramoprismatoolithus are characterized by a prismatic microstructure with branching ridges on the outer surface. The researchers carefully analyzed the physical characteristics of the eggshell fragments and impressions and performed phylogenetic analysis (which examines the evolutionary development of a species, group of organisms, or a particular characteristic they have) to determine the type of dinosaur most likely to have laid the eggs. Most of the egg material, including five fragments and four impressions, belonged to a new egg genus and species, which the researchers named Ramoprismatoolithus okurai. Two eggshell impressions belonged to indeterminate egg groups. Two of the eggshell fragments were identified as belonging to the Testudoolithidae family, a family of turtle egg fossils. The team described and classified the fossils into at least two types. The study focused on seven eggshell fragments and six eggshell impressions, which were collected from the Okurodani Formation in Gifu Prefecture between 19. Early Cretaceous eggshell fragments, the oldest found in Japan, offer a glimpse into the ecosystem of dinosaurs during this time period.Ī research team from the University of Tsukuba has recently published a study in Historical Biology, where they examined fossil eggshell fragments found in northern central Japan. This is particularly valuable for understanding the smaller animals that were less likely to be preserved. Tiny eggshell fragments can provide insights into Mesozoic ecosystems that fossils of bones and teeth do not. Credit: University of Tsukubaįossilized eggshells from Gifu Prefecture, Japan, dating back to the Early Cretaceous period, reveal previously unknown egg species from a small theropod dinosaur.ĭinosaurs left behind more evidence than just giant skeletons.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |