Mathers, Thomas C.; Hammond, Robert L.; Jenner, Ronald A.; Hänfling, Bernd; Gómez, Africa (2013). "Multiple global radiations in tadpole shrimps challenge the concept of 'living fossils' ". PeerJ. 1: e62. doi: 10.7717/peerj.62. PMC 3628881. PMID 23638400. {{ cite journal}}: CS1 maint: unflagged free DOI ( link) Living fossils exhibit stasis (also called "bradytely") over geologically long time scales. Popular literature may wrongly claim that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims. [1] [2] [3] Harmon, L.; Losos, J.; Davies, T.; Gillespie, R.; Gittleman, J.; Jennings, W.; etal. (2010). "Early bursts of body size and shape evolution are rare in comparative data". Evolution. 64 (8): 2385–2396. doi: 10.1111/j.1558-5646.2010.01025.x. PMID 20455932. S2CID 17544335. 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.

Silutitan and Hamititanadd to our knowledge of the sauropods that lived in what is now Asia during the early Cretaceous period, from 145 million to 100 million years ago. The discovery also refines scientists’ picture of how sauropod dinosaurs spread out and diversified across ancient Earth. 10. A Japanese dinosaur from the Mesozoic Era’s last chapter cyanobacteria". ircamera.as.arizona.edu. Archived from the original on 2019-05-03 . Retrieved 2019-04-27. Such criteria are neither well-defined nor clearly quantifiable, but modern methods for analyzing evolutionary dynamics can document the distinctive tempo of stasis. [6] [7] [8] Lineages that exhibit stasis over very short time scales are not considered living fossils; what is poorly-defined is the time scale over which the morphology must persist for that lineage to be recognized as a living fossil. The term “living fossil” is an imperfect concept, which has caused much consternation among paleontologists and biologists as they have sifted through the fossil record over time. It is meant to describe an organism that has remained relatively unchanged over millions of years, or one that has no, or very few, close surviving relatives. The concept is an informal window into the past, a way for us to consider species as they may have been millions of years ago by observing their modern descendents. Of all living creatures, crocodiles perhaps bear the greatest resemblance to dinosaurs; in fact, they were contemporaries. The semiaquitic reptiles first appeared about 200 million years ago, or 30 million years after the dinos. Yet despite all the time that's passed since, there are only 24 species today, all of which look remarkably like their ancestors, and each other, except for some variation in skull shape. Compare that to the wild diversity of, say, birds, who in a much shorter interval produced around 10,000 species.The chambered part of the ammonite shell is called a phragmocone. It contains a series of progressively larger chambers, called camerae (sing. camera) that are divided by thin walls called septa (sing. septum). Only the last and largest chamber, the body chamber, was occupied by the living animal at any given moment. As it grew, it added newer and larger chambers to the open end of the coil. Where the outer whorl of an ammonite shell largely covers the preceding whorls, the specimen is said to be involute (e.g., Anahoplites). Where it does not cover those preceding, the specimen is said to be evolute (e.g., Dactylioceras).

a b McGowan, Alistair J.; Smith, Andrew B. (May 2007). "Ammonoids Across the Permian/Triassic Boundary: A Cladistic Perspective". Palaeontology. 50 (3): 573–590. Bibcode: 2007Palgy..50..573M. doi: 10.1111/j.1475-4983.2007.00653.x.Lynch, M (1990). "The rate of evolution in mammals from the standpoint of the neutral expectation". The American Naturalist. 136 (6): 727–741. doi: 10.1086/285128. S2CID 11055926. In the past, scientists calculated fish ages by counting big lines on a specific coelacanth scale. But the French scientists found they were missing smaller lines that could only be seen using polarised light — the technique used to work out the age of commercial fish. Some paleontologists believe that living fossils with large distributions (such as Triops cancriformis) are not real living fossils. In the case of Triops cancriformis (living from the Triassic until now), the Triassic specimens lost most of their appendages (mostly only carapaces remain), and they have not been thoroughly examined since 1938. Although some ancient Greek and Roman scientists recognized that fossils were the remains of life forms, many early scholars believed fossils were evidence of mythological creatures such as dragons. From the Middle Ages until the early 1700s, fossils were widely regarded as works of the devil or of a higher power. Many people believed the remains had special curative or destructive powers. Many scholars also believed that fossils were remains left by Noah's flood and other disasters documented in the Hebrew holy book.