IUCN Red List Of Threatened Species: Nasikabatrachus Sahyadrensis". IUCN Red List Of Threatened Species.

Monks, Neale; Palmer, Philip (2002). Ammonites. Smithsonian Institution Press. ISBN 978-1-58834-024-5. Stegouros is a bizarre anatomical mosaic. The dinosaur’s skull, teeth, and club-like tail are classically ankylosaur, resembling Ankylosaurus and other late armored dinosaurs. However, the dinosaur’s slender limb bones and pelvis resemble those of stegosaurs such as Stegosaurus, which had been extinct for tens of millions of years by the time of Stegouros. ( See how Stegouros may shake up the armored dinosaurs’ family tree.)

One feature found in shells of the modern Nautilus is the variation in the shape and size of the shell according to the sex of the animal, the shell of the male being slightly smaller and wider than that of the female. This sexual dimorphism is thought to be an explanation for the variation in size of certain ammonite shells of the same species, the larger shell (the macroconch) being female, and the smaller shell (the microconch) being male. This is thought to be because the female required a larger body size for egg production. A good example of this sexual variation is found in Bifericeras from the early part of the Jurassic period of Europe. Tlatolophus probably stretched about 26 feet from snout to tail and stood about 6.5 feet tall at the hip. Based on its well-preserved skull, scientists think that the animal was a close cousin of the iconic crested lambeosaur Parasaurolophus, which are seen drinking from a lake near the beginning of the movie Jurassic Park. Pelicans ( Pelecanus) – form has been virtually unchanged since the Eocene, and is noted to have been even more conserved across the Cenozoic than that of crocodiles. [48]

Machalski, Marcin; Heinberg, Claus (2005-12-01). "Evidence for ammonite survival into the Danian (Paleogene) from the Cerithium Limestone at Stevns Klint, Denmark". Bulletin of the Geological Society of Denmark. 52: 2005–12. doi: 10.37570/bgsd-2005-52-08. a b Montresor, M.; Janofske, D.; Willems, H. (1997). "The cyst-theca relationship in Calciodinellum operosum emend. (Peridiniales, Dinophyceae) and a new approach for the study of calcareous cysts". Journal of Phycology. 33 (1): 122–131. doi: 10.1111/j.0022-3646.1997.00122.x. S2CID 84169394. Modern paleontologists have a variety of tools that help them discover, examine, and describe fossils. Electron microscopes allow paleontologists to study the tiniest details of the smallest fossils. X-ray machines and CT scanners reveal fossils' internal structures. Advanced computer programs can analyze fossil data, reconstruct skeletons, and visualize the bodies and movements of extinct organisms.In his 1859 book On the Origin of Species, esteemed naturalist Charles Darwin coined the term “living fossil” to describe living organisms that appeared unchanged from their extinct fossil relatives. The term has since been used to describe long-enduring lineages, relict populations, groups with low diversity, and groups with DNA that has hardly changed in millions of years.