Morelle, Rebecca (4 June 2013). "Rediscovered hula painted frog 'is a living fossil' ". BBC News . Retrieved 4 June 2013.

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] Nagalingum NS, Marshall CR, Quental TB, Rai HS, Little DP, Mathews S (11 November 2011). "Recent synchronous radiation of a living fossil". Science (published 20 October 2011). 334 (6057): 796–799. Bibcode: 2011Sci...334..796N. doi: 10.1126/science.1209926. PMID 22021670. S2CID 206535984. A fossil (from Classical Latin fossilis, lit. 'obtained by digging') [1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record.The Australian lungfish ( Neoceratodus fosteri), also known as the Queensland lungfish, is an example of an organism that meets this criterion. Fossils identical to modern specimens have been dated at over 100 million years old. Modern Queensland lungfish have existed as a species for almost 30 million years. The contemporary nurse shark has existed for more than 112 million years, making this species one of the oldest, if not actually the oldest extant vertebrate species. Fossils are echoes of an ancient past. Find out about the two major categories of fossils, how fossilization occurs, and how fossils can help paint a picture of the planet's history. 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 lateral region involves the first saddle and lobe pair past the external region as the suture line extends up the side of the shell. The lateral saddle and lobe are usually larger than the ventral saddle and lobe. Additional lobes developing towards the inner edge of a whorl are labelled umbilical lobes, which increase in number through ammonoid evolution as well as an individual ammonoid's development. In many cases the distinction between the lateral and umbilical regions are unclear; new umbilical features can develop from subdivisions of other umbilical features, or from subdivisions of lateral features. Lobes and saddles which are so far towards the center of the whorl that they are covered up by succeeding whorls are labelled internal (or dorsal) lobes and saddles. Wippich, M. G. E.; Lehmann, J. (2004). " Allocrioceras from the Cenomanian (mid-Cretaceous) of the Lebanon and its bearing on the palaeobiological interpretation of heteromorphic ammonites". Palaeontology. 47 (5): 1093–1107. Bibcode: 2004Palgy..47.1093W. doi: 10.1111/j.0031-0239.2004.00408.x. Smith, C. P. A.; Landman, N. H.; Bardin, J.; Kruta, I. (4 June 2021). "New evidence from exceptionally "well-preserved" specimens sheds light on the structure of the ammonite brachial crown". Scientific Reports. 11 (1): 11862. Bibcode: 2021NatSR..1111862S. doi: 10.1038/s41598-021-89998-4. PMC 8178333. PMID 34088905. cyanobacteria". ircamera.as.arizona.edu. Archived from the original on 2019-05-03 . Retrieved 2019-04-27. Monks, Neale; Palmer, Philip (2002). Ammonites. Smithsonian Institution Press. ISBN 978-1-58834-024-5.

What did ammonites eat and what ate them?

Morton, N (1981). "Aptychi: the myth of the ammonite operculum". Lethaia. 14 (1): 57–61. doi: 10.1111/j.1502-3931.1981.tb01074.x. Even though coelacanths are unrelated genetically to other deep-sea creatures such as sharks and rays, they are similar in ageing slowly, Ernande said. Sharks can live to be hundreds of years old. One example of a concept that could be confused with "living fossil" is that of a " Lazarus taxon", but the two are not equivalent; a Lazarus taxon (whether a single species or a group of related species) is one that suddenly reappears, either in the fossil record or in nature, as if the fossil had "come to life again". [11] In contrast to "Lazarus taxa", a living fossil in most senses is a species or lineage that has undergone exceptionally little change throughout a long fossil record, giving the impression that the extant taxon had remained identical through the entire fossil and modern period. Because of the mathematical inevitability of genetic drift, though, the DNA of the modern species is necessarily different from that of its distant, similar-looking ancestor. They almost certainly would not be able to cross-reproduce, and are not the same species. [12] The National Geographic Society supports field work in paleontology throughout the world. Emerging Explorer Zeresenay "Zeray" Alemseged conducts studies in northern Ethiopia. There, Alemseged and his colleagues unearth and study fossils that contribute to the understanding of human evolution. There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.

Initially museum staff thought the bone was part of the Moroccan stegosaur Adratiklit, since it came from the same area in the country’s Atlas Mountains. But Maidment and her colleagues soon realized that the fossil belonged to something new—making it much more significant. The Natural History Museum then established an agreement with Sidi Mohamed Ben Abdellah University in Fez, Morocco, to research the fossil together. An operational definition was proposed in 2017, where a 'living fossil' lineage has a slow rate of evolution and occurs close to the middle of morphological variation (the centroid of morphospace) among related taxa (i.e. a species is morphologically conservative among relatives). [30] The scientific accuracy of the morphometric analyses used to classify tuatara as a living fossil under this definition have been criticised however, [31] which prompted a rebuttal from the original authors. [32] Examples [ edit ] Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition. Most trilobites had eyes, although blind forms are known. The eyes are situated on the inner edge of the free cheek, adjacent to the fixed cheek. 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).

In November a Brazilian research team unveiled a remarkable toothless dinosaur in the journal Scientific Reports. The fossil creature, called Berthasaura leopoldinae, is the most complete fossil of its kind and age ever found in Brazil. It is named for two influential Brazilian women: Bertha Maria Júlia Lutz, a zoologist and pioneering women’s rights advocate, and Brazil’s first empress, Maria Leopoldina, who played a pivotal role in securing the country’s independence. 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. Butler, M.; King, A. (2004). "Phylogenetic comparative analysis: A modeling approach for adaptive evolution". The American Naturalist. 164 (6): 683–695. doi: 10.1086/426002. PMID 29641928. S2CID 4795316.