when did the first fish appear in the fossil record
530 million years ago
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Evolution of fish The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include "Haikouichthys". During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish,
Evolution of fish
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shark, Cladoselache, was a cladodont existing about 370 million years ago. It had the typical cladodont teeth, which probably also were not regularly replaced like those of modern sharks, but did appear to wear down from use. This shark did indeed appear to swallow its prey whole, fossil examples containing batches of fish arranged tail-first where the shark's stomach should be. Around this time, the stethacanthus genus of shark also begins to appear in the fossil record. Also a cladodont, it survived from the late Devonian to the early Carboniferous, dying out about 320 million years ago. While the earliest
Cladodont
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appear in the fossil record in the middle Eocene with the fossil "Eosalmo driftwoodensis", which was first described from fossils found at Driftwood Creek, central British Columbia. This genus shares traits found in the Salmoninae, whitefish, and grayling lineages. Hence, "E. driftwoodensis" is an archaic salmonid, representing an important stage in salmonid evolution. A gap appears in the salmonine fossil record after "E. driftwoodensis" until about seven million years ago (mya), in the late Miocene, when trout-like fossils appear in Idaho, in the Clarkia Lake beds. Several of these species appear to be "Oncorhynchus"—the current genus for Pacific salmon and
Salmonidae
38993
fish and invertebrate populations. Bryozoans have spread diseases to fish farms and fishermen. Chemicals extracted from a marine bryozoan species have been investigated for treatment of cancer and Alzheimer's disease, but analyses have not been encouraging. Mineralized skeletons of bryozoans first appear in rocks from the Early Ordovician period, making it the last major phylum to appear in the fossil record. This has led researchers to suspect that bryozoans arose earlier but were initially unmineralized, and may have differed significantly from fossilized and modern forms. Early fossils are mainly of erect forms, but encrusting forms gradually became dominant. It is
Bryozoa
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located on the palatine bone. Snakes do not have an extensive fossil record; the oldest known fossil is from between early and late Cretaceous period. There were Tertiary fossil snakes that became extinct by the end of the Eocene period. The first colubrid also appeared in the Eocene period. Lizards first appeared in the middle Jurassic period, and this is when the scincomorph and the anguimorph lizards were first seen. The Gekkotans first appear in the late Jurassic period and the iguanians first appear in the late Cretaceous period. The lizards of the Cretaceous period represent extinct genera and species.
Lepidosauria
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when the university's museum was merged with the Museum of the High Plains. The museum is the home of the famous Cretaceous fossil "Gillicus in Xiphactinus", better known as the "fish within a fish," which shows a small fossil fish inside the stomach of a larger fossil fish. In 2010, researchers at the museum showed that plankton-eating fish flourished in the ocean at the same time as the dinosaurs, filling in a 106-million-year gap in the fossil record. One of the authors of the paper was Mike Everhart, a curator of paleontology at the museum. FHSU comprises four colleges (Arts
Fort Hays State University
17372107
Fish egg fossil Fish egg fossils are the fossilized remains of fish eggs. Fossil fish eggs have an extensive record going at least as far back as the Devonian and spanning into the Cenozoic era. The eggs of many different fish taxa have contributed to this record, including lobe-finned fish, placoderms, and sharks. Occasionally eggs are preserved still within the mother's body, or associated with fossil embryos. Some fossil eggs possibly laid by fish cannot be confidently distinguished from those laid by amphibians; for example, the ichnogenus "Mazonova" is known from impressions of eggs which resemble eggs of both fish
Fish egg fossil
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soft, gelatinous eggs decompose quickly and have little chance to fossilize. Another major group of Mesozoic cephalopods, the belemnoids, have no documented eggs in the fossil record whatsoever, although this may be because scientists have not properly searched for them rather than an actual absence from the fossil record. Fossil fish eggs have an extensive record going at least as far back as the Devonian and spanning into the Cenozoic era. The eggs of many different fish taxa have contributed to this record, including lobe-finned fish, placoderms, and sharks. Occasionally eggs are preserved still within the mother's body, or associated
Egg fossil
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families appear to have diverged during the late Jurassic to early Cretaceous (170–120 mya). As other fish, chimaeras have a number of parasites. "Chimaericola leptogaster" (Chimaericolidae) is a monogenean parasite of the gills of "Chimaera monstrosa"; the species can attain in length. Chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, rat fish, spookfish or rabbit fish; the latter three names are not to be confused with rattails, Opisthoproctidae or Siganidae, respectively. At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks, though their last common
Chimaera
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not appear in the fossil record until the Carboniferous. Based on the size of the bone, the "Hynerpeton" individual to which it belonged had an estimated length of .7 meters (2.3 feet). The cleithrum portion is smooth, rather than rough-textured as in tetrapodomorph fish. In addition, the upper portion of the cleithrum is expanded and slightly tilted forwards, a derived character similar to "Tulerpeton" and true tetrapods. The scapulocoracoid region is large when seen from the side but very thin when seen from below. The glenoid fossa (shoulder socket) is positioned on the posterolateral (outer and rear) edge of the
Hynerpeton
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the fossil record before the end of the Cambrian, namely the Branchiopoda, Maxillopoda (including barnacles and tongue worms) and Malacostraca; there is some debate as to whether or not Cambrian animals assigned to Ostracoda are truly ostracods, which would otherwise start in the Ordovician. The only classes to appear later are the Cephalocarida, which have no fossil record, and the Remipedia, which were first described from the fossil "Tesnusocaris goldichi", but do not appear until the Carboniferous. Most of the early crustaceans are rare, but fossil crustaceans become abundant from the Carboniferous period onwards. Within the Malacostraca, no fossils are
Crustacean
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The earliest known fossil diatoms date from the early Jurassic (~185 Ma ago), although the molecular clock and sedimentary evidence suggests an earlier origin. It has been suggested that their origin may be related to the end-Permian mass extinction (~250 Ma), after which many marine niches were opened. The gap between this event and the time that fossil diatoms first appear may indicate a period when diatoms were unsilicified and their evolution was cryptic. Since the advent of silicification, diatoms have made a significant impression on the fossil record, with major fossil deposits found as far back as the early
Diatom
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on land. The first tetrapods appear in the fossil record over a period, the beginning and end of which are marked with extinction events. This lasted until the end of the Devonian 359 mya. The ancestors of all tetrapods began adapting to walking on land, their strong pectoral and pelvic fins gradually evolved into legs (see "Tiktaalik"). In the oceans, primitive sharks became more numerous than in the Silurian and the late Ordovician. The first ammonite mollusks appeared. Trilobites, the mollusk-like brachiopods and the great coral reefs, were still common. The Late Devonian extinction occurred at the beginning of the
Evolution of fish
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with fossil embryos. Some fossil eggs possibly laid by fish cannot be confidently distinguished from those laid by amphibians. Several fossilized fish or amphibian eggs have been classified as ichnogenera, including "Mazonova", "Archaeoovulus", "Chimaerotheca", "Fayolia", and "Vetacapsula". The fossil record of reptile eggs goes back at least as far as the Early Permian. However, since the earliest reptile eggs probably had soft shells with little preservation potential, reptilian eggs may go back significantly farther than their fossil record. Many ancient reptile groups are known from egg fossils including crocodilians, dinosaurs, and turtles. Some ancient reptiles, like ichthyosaurs and plesiosaurs are
Egg fossil
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considered to be the world's greatest palaeontological record of fossils from the Devonian Period, known as the 'Age of Fishes'. Five of the six main fossil fish groups from this period (dating from 370 million years ago) can be found here. A great quantity of some of the best-preserved fossil specimens of lobe-finned fish, ancestors to the tetrapods (believed to be the first four-legged air-breathing terrestrial vertebrates), were found here. The fossil site was first discovered in 1842, by Abraham Gesner (1797–1864), a geologist and medical doctor, and a pioneer in the petroleum industry. Gesner found a vast array of
Miguasha National Park
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including the cladoxylalean ferns, lepidosigillarioid lycopsids, and aneurophyte and archaeopterid progymnosperms. Fish were also undergoing a huge radiation, and the first tetrapods, such as "Tiktaalik", were beginning to evolve leg-like structures. Extinction rates appear to have been higher than the background rate, for an extended interval covering the last 20–25 million years of the Devonian. During this time, about eight to ten distinct events can be seen, of which two stand out as particularly severe. The Kellwasser event was preceded by a longer period of prolonged biodiversity loss. The fossil record of the first 15 million years of the Carboniferous
Late Devonian extinction
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to its seafood red list—a list of fish commonly sold worldwide with a high likelihood of being sourced from unsustainable fisheries. One family, the Lophiidae, is of commercial interest with fisheries found in western Europe, eastern North America, Africa, and East Asia. In Europe and North America, the tail meat of fish of the genus "Lophius", known as monkfish or goosefish (North America), is widely used in cooking, and is often compared to lobster tail in taste and texture. In Asia, especially Korea and Japan, monkfish liver, known as "ankimo", is considered a delicacy. Anglerfish appear in the fossil record
Anglerfish
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at the point when jawless fish first became more developed and coincides with the emergence of placoderms (armored fish) in both North America and Europe. Stylonurines of the surviving hibbertopterid and mycteroptid families completely avoided competition with fish by evolving towards a new and distinct ecological niche. These families experienced a radiation and diversification through the Late Devonian and Early Carboniferous, the last ever radiation within the eurypterids, which gave rise to several new forms capable of "sweep-feeding" (raking through the substrate in search of prey). Only three eurypterid families–Adelophthalmidae, Hibbertopteridae and Mycteroptidae (whose fossil record at this time only
Eurypterid
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macroscopic. However, such large animals should have left traces in the sediment in which they moved, and evidence of such traces first appear relatively late in the fossil record — long after the urbilaterian would have lived. This leads to suggestions of a small urbilaterian, which is the supposed state of the ancestor of protostomes, deuterostomes and acoelomorphs. The first evidence of bilateria in the fossil record comes from trace fossils in sediments towards the end of the Ediacaran period (about ), and the first fully accepted fossil of a bilaterian "organism" is "Kimberella", dating to . There are earlier,
Urbilaterian
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fossil record does not preserve any fish, however some strata of that age found in the Upper Peninsula correspond to deposits of that age on Ontario's St. Joseph Island where such finds have been made. Since pieces of the bony armor that once embedded in the skin of the fish "Astraspis" were preserved at St. Joseph's, the similarly aged nearby Middle Ordovician rocks of the Upper Peninsula are also likely to preserve similar fish fossils. If this supposition is correct, then Michigan's fish fossil record may go back as far 460 million years ago. In the next period, the Silurian,
Paleontology in Michigan
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The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate (Polypodiidae) and eusporangiate ferns, the latter itself comprising ferns other than those denominated true ferns, including horsetails or scouring rushes, whisk ferns, marattioid ferns, and ophioglossoid ferns. Ferns first appear in the fossil record about 360 million years ago in the late Devonian period, but many of the current families and species did not appear until roughly 145 million years ago in the early Cretaceous, after flowering plants came to dominate many environments. The fern
Fern
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deleted, but all apparent miRNA sequences still show full duplication, with potential to influence regulation of the rainbow trout's genome. This pattern of partial tetraploidy is thought to be reflected in the rest of extant salmonids. The first fossil species representing a true salmonid fish ("E. driftwoodensis") does not appear until the middle Eocene. This fossil already displays traits associated with extant salmonids, but as the genome of E. "driftwoodensis" cannot be sequenced, it cannot be confirmed if triploidy was present in this animal at this point in time. This fossil is also significantly younger than the proposed salmonid divergence
Salmonidae
88835
antennae, elytra with more fully developed venation and more irregular longitudinal ribbing, and abdomen and ovipositor extending beyond the apex of the elytra. In the Permian–Triassic extinction event at the end of the Permian, some 30% of all insect species became extinct, so the fossil record of insects only includes beetles from the Lower Triassic . Around this time, during the Late Triassic, fungus-feeding species such as Cupedidae appear in the fossil record. In the stages of the Upper Triassic, alga-feeding insects such as Triaplidae and Hydrophilidae begin to appear, alongside predatory water beetles. The first weevils, including the Obrienidae,
Beetle
4588659
existed alongside the Sphenophyllales, but diversified as that group disappeared into extinction, gradually dwindling in diversity to today's single genus "Equisetum". The organisms first appear in the fossil record during the late Devonian, a time when land plants were undergoing a rapid diversification, with roots, seeds and leaves having only just evolved. (See Evolutionary history of plants) However, plants had already been on the land for almost a hundred million years, with the first evidence of land plants dating to . The horsetails and their fossil relatives have long been recognized as distinct from other seedless vascular plants. Before the
Equisetopsida
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and this group may have split early on from other agnathans. The first jawed vertebrates probably developed during the late Ordovician period. They are first represented in the fossil record from the Silurian by two groups of fish: the armoured fish known as placoderms, which evolved from the ostracoderms; and the Acanthodii (or spiny sharks). The jawed fish that are still extant in modern days also appeared in late Silurian: the Chondrichthyes (or cartilaginous fish) and the Osteichthyes (or bony fish). The bony fish evolved into two separate groups: the Actinopterygii (or ray-finned fish) and Sarcopterygii (which includes the lobe-finned
Evolution of fish
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Gogo Formation The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community. The formation is named after Gogo Station, a cattle station where outcrops appear and fossils are often collected from, as is nearby Fossil Downs Station. The reef, which now stands up abruptly in the western Australian desert (as the Windjana Limestone), was first identified in 1940 by paleontologist Curt Teichert, who discovered the first fossil fish from the region. It has been described for the layman by the driving force behind collecting expeditions at the Gogo
Gogo Formation
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Among others, these fossils have been recovered from the Gogo Formation: Gogo Formation The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community. The formation is named after Gogo Station, a cattle station where outcrops appear and fossils are often collected from, as is nearby Fossil Downs Station. The reef, which now stands up abruptly in the western Australian desert (as the Windjana Limestone), was first identified in 1940 by paleontologist Curt Teichert, who discovered the first fossil fish from the region. It has been described for the
Gogo Formation
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type and could help unravel how the nervous system evolved in early animals. The fossil was excavated in southern China. Individual nerves are visible. Fossilized soft tissue is rare, but this particular find, by researchers in the UK, China and Germany, represents the most detailed example of a preserved nervous system yet discovered. "Chengjiangocaris kunmingensis" lived during the Cambrian explosion, a period of rapid evolutionary development about half a billion years ago when most major animal groups first appear in the fossil record. "C. kunmingensis" belongs to a group of animals called fuxianhuiids, and was an early ancestor of modern
Chengjiangocaris
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"et al." 2015. The fossil record of snakes is relatively poor because snake skeletons are typically small and fragile, making fossilization uncommon. Fossils readily identifiable as snakes (though often retaining hind limbs) first appear in the fossil record during the Cretaceous period. The earliest known snake fossils come from sites in Utah and Algeria, represented by the genera "Coniophis" and "Lapparentophis", respectively. These fossil sites have been tentatively dated to the Albian or Cenomanian age of the late Cretaceous, between 112 and 94 Ma ago. However, an even greater age has been suggested for one of the Algerian sites, which
Ophidia
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divergence of the crown group. The presence of stem taxa in the fossil record does not indicate that crown groups have evolved, and stem taxa may survive for millions of years after the crown taxa appear. For this reason, the fossil record can only suggest a hard minimum boundary for divergence dates, which corresponds to the first appearance of a crown taxon. Furthermore, Pozzi "et al." pointed out that the supplementary material published by Zalmout "et al." demonstrated that Pliopithecoidea were more closely related to living catarrhines than "Saadanius". The fossil find has also been seen by the SGS as
Saadanius
607131
as a variety of extant mammalian species, dominated by the marsupials,currently however there is limited taxonomic research into Australia's mammals. The fossil record shows that monotremes have been present in Australia since the Early Cretaceous 145–99 MYA, and that marsupials and placental mammals date from the Eocene 56–34 MYA, when modern mammals first appeared in the fossil record. Although terrestrial marsupials and placental mammals did coexist in Australia in the Eocene, only the marsupials have survived to the present. Non-volant placental mammals made their reappearance in Australia in the Miocene, when Australia moved closer to Indonesia, and rodents started to
Fauna of Australia
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movies. Fish do not represent a monophyletic group, and therefore the "evolution of fish" is not studied as a single event. Early fish from the fossil record are represented by a group of small, jawless, armored fish known as ostracoderms. Jawless fish lineages are mostly extinct. An extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils. The diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, or a combination of factors. Fish
Fish
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ago, when the first craft and use of stone tools by hominids appears in the archaeological record, until around 120,000 years ago when important evolutionary and technological changes ushered in the Middle Palaeolithic. The earliest hominids, known as Homo erectus and recognisable as human, appear in the archaeological record between 1,000,000-500,000 years ago. Locally typified by the fossil, Lampang Man. About 1,000,000 years ago, "Homo erectus" moved to Asia from Africa, where it had originated. Its use and control of fire was an important tool in its hunter-gatherer means of subsistence. "Homo erectus's " skull was smaller and thicker than
Prehistoric Thailand
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and amphibians. Paleontologist B.K. Hall has observed that the discovery of fossil fish eggs, embryos and larvae link the sciences of paleontology with evo-devo. Fossilized egg cases that may have been laid by an elasmobranch or chimaeroid are known from as far back as the Devonian period. Egg sacs that can more confidently be referred to those taxa are known from the Carboniferous to Oligocene, although no embryos are known from these. Shark eggs have been recognized in the fossil record. More than thirty fossil shark egg capsules have been discovered at the Bear River Seep Deposit of Washington state
Fish egg fossil
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record. Vertebrate fossil fauna found in the area includes "Australodelphis mirus", a Pliocene dolphin that is the first cetacean fossil recovered from the Antarctic margin of the Southern Ocean that postdates the break-up of Gondwana. Other fossil cetaceans have also been found in the area, as well as a fish, a diverse invertebrate fauna that includes molluscs, gastropods, marine diatoms, and Antarctica’s first Pliocene decapod crustacean. The site is protected under the Antarctic Treaty System as Antarctic Specially Protected Area (ASPA) No.143. Mule Peninsula Mule Peninsula is an irregularly shaped rocky peninsula between Ellis Fjord and Krok Fjord in the
Mule Peninsula
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in a freshwater (possibly cool-climate subalpine) lake.The site is an important element of Australia's fossil record, with plants, insects (including mayflies, dragonflies, cockroaches, beetles, fleas, flies and wasps), spiders, crustaceans and fish recovered. Among them is the unusual finding of a fossil horseshoe crab described as "Victalimulus mcqueeni". Small segments of a leafy twig have been recovered that were thought to be one of the oldest angiosperms (flowering plants) discovered; more recent examination reports anatomy more typical of a gnetophyte, a group of organisms for which there is a scant fossil record. A fossil member of the Ginkgo family, "Ginkgoites
Koonwarra, Victoria
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Olsen’s Gap, which is used to describe the evolutionary gap in the tetrapod fossil record between the appearance of the more derived therapsids and their ancestors, the pelycosaurs. The rocks of the Abrahamskraal Formation and its geological correlates abroad hold the promise of that fossil gap being bridged through future research endeavors in the years to come. More notable fossil species includes the dicynodont "Diictodon feliceps" which first appears in the upper sections of this formation, remaining ubiquitous until the Permian-Triassic boundary. Finally, fossils of temnospondyl amphibians such as of "Rhinosuchus", the fish "Namaichthys", invertebrate fossils of molluscs, invertebrate trackways
Abrahamskraal Formation
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primitive mysticete "Cophocetus oregonensis" appear in Oregon's fossil record in this period. Sirenians and desmostylids have also been found in coastal assemblages. Paleontologists believe that animals in these two groups fed on clams and other mollusks, which is consistent with fossil clam beds found in the Coast Range. The saber-tooth salmon "Oncorhynchus rastrosus" also swam in Oregon's Neogene rivers.Global cooling in the late Neogene gave way to glaciation in the Quaternary. Oregon's mountain ranges were covered in large ice caps, although the Cordilleran Ice Sheet did not extend into the state. Evidence of ice cap increase and decrease is preserved
Paleontology in Oregon
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Mya have been found in the US Midwest, however fossils of the modern river otter did not appear in North America until about 1.9 Mya. The earliest known fossil of "Lontra canadensis", found in the US Midwest, is from the Irvingtonian stage (1,800,000 to 300,000 years ago). The oldest fossil record of an Old World river otter comes from the late Pliocene epoch (3.6 to 1.8 Mya). The New World river otters originated from the Old World river otters after a migration across the Bering Land Bridge, which existed off and on between 1.8 million and 10,000 years ago. The
North American river otter
711444
also known as the end-Frasnian extinction. This marked the beginning of a gap in the tetrapod fossil record known as the Famennian gap, occupying roughly the first half of the Famennian stage. The oldest near-complete tetrapod fossils, Acanthostega and Ichthyostega, date from the second half of the Fammennian. Although both were essentially four-footed fish, Ichthyostega is the earliest known tetrapod that may have had the ability to pull itself onto land and drag itself forward with its forelimbs. There is no evidence that it did so, only that it may have been anatomically capable of doing so. The end-Fammenian marked
Tetrapod
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of rock layers. These works helped establish the antiquity of the Earth. Cuvier advocated catastrophism to explain the patterns of extinction and faunal succession revealed by the fossil record. Knowledge of the fossil record continued to advance rapidly during the first few decades of the 19th century. By the 1840s, the outlines of the geologic timescale were becoming clear, and in 1841 John Phillips named three major eras, based on the predominant fauna of each: the Paleozoic, dominated by marine invertebrates and fish, the Mesozoic, the age of reptiles, and the current Cenozoic age of mammals. This progressive picture of
History of evolutionary thought
7086157
Cupedidae) appear in the fossil record. In the stages of the Upper Triassic representatives of the algophagous, or algae feeding species (i.e., Triaplidae and Hydrophilidae) begin to appear, as well as predatory water beetles. The first primitive weevils appear (i.e., Obrienidae), as well as the first representatives of the rove beetles (i.e., Staphylinidae), which show no marked difference in physique compared to recent species. This was also around the first time evidence of diverse freshwater insect fauna appeared. Some of the oldest living families also appear around during the Triassic. Hemiptera included the Cercopidae, the Cicadellidae, the Cixiidae, and the
Evolution of insects
2216679
either in the fossil record or in nature, as if the fossil had "come to life again". 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. The average species turnover time, meaning the time between when a species first is established and when it finally disappears, varies widely among phyla, but averages about 2–3 million years. A living taxon that had long been thought to
Living fossil
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early forests. Despite these advantages, it is common for fertilized ovules to fail to mature as seeds. Also during seed dormancy (often associated with unpredictable and stressful conditions) DNA damage accumulates. Thus DNA damage appears to be a basic problem for survival of seed plants, just as DNA damage is a major problem for life in general. Flowers are modified leaves possessed only by the angiosperms, which are relatively late to appear in the fossil record. The group originated and diversified during the Early Cretaceous and became ecologically significant thereafter. Flower-like structures first appear in the fossil records some ~130
Evolutionary history of plants
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their evolutionary history is obscure. In ancient seas jawless vertebrate fish led to jawed fish, and thence to all other vertebrates, including humans. Being the only extant jawless vertebrates and a virtual time capsule of embryology and DNA, lampreys and hagfish are of immense scientific interest. Knowing the period during which they became parasitic would shed light on how typical they are of ancient fish. Having no bone tissue, effectively being essentially boneless, their cartilaginous framework leaves almost no fossil record - a mere three fossil species had previously been described, and in none of these was a sucker disc
Priscomyzon
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of its discovery "Lazarussuchus" was considered an example of the Lazarus effect because its "unexpected" presence followed a long gap in the choristodere fossil record. However, older specimens of "Lazarussuchus" have been found that extend its fossil range to before the Eocene, closing the apparent gap in the record. "Lazarussuchus" has been interpreted as the most basal member of Choristodera, meaning that its lineage must have been the earliest to branch off from the group. Since the first definitive choristoderes appear in the Middle Jurassic, the lineage represented by "Lazarussuchus" must have extended at least as far back as the
Lazarussuchus
401293
as "adder" went on to narrow in meaning, though in Old English "næddre" was the general word for snake. The other term, "serpent", is from French, ultimately from Indo-European "*serp-" (to creep), which also gave Ancient Greek "hérpō" (ἕρπω) "I crawl". The fossil record of snakes is relatively poor because snake skeletons are typically small and fragile making fossilization uncommon. Fossils readily identifiable as snakes (though often retaining hind limbs) first appear in the fossil record during the Cretaceous period. The earliest known true snake fossils (members of the crown group Serpentes) come from the marine simoliophiids, the oldest of
Snake
533776
oldest known echinoderm fossil may be "Arkarua" from the Precambrian of Australia. It is a disc-like fossil with radial ridges on the rim and a five-pointed central depression marked with radial lines. However, no stereom or internal structure showing a water vascular system is present and the identification is inconclusive. The first universally accepted echinoderms appear in the Lower Cambrian period, asterozoans appeared in the Ordovician and the crinoids were a dominant group in the Paleozoic. Echinoderms left behind an extensive fossil record. It is hypothesised that the ancestor of all echinoderms was a simple, motile, bilaterally symmetrical animal with
Echinoderm
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a novelty were to evolve gradually in an animal's juvenile form, then its development would not appear in the fossil record at all, but if the species were then to undergo neoteny (a form of paedomorphosis in which sexual maturity is reached while in an otherwise juvenile form), then the feature would appear suddenly in the fossil record, despite having evolved gradually. De Beer worked on paleornithology and general evolutionary theory, and was largely responsible for elucidating the concept of mosaic evolution, as illustrated by his review of "Archaeopteryx" in 1954. De Beer's also reviewed Haeckel's concept of heterochrony, with
Gavin de Beer
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fauna. This is also significant because the fossils present during this period of the Pliocene represent species which were alive during the early stages in the evolution of man, albeit on a different continent. The fossil beds were designated a National Natural Landmark in 1975. Many other species are also found in the fossil record, including mastodons, saber-toothed cats, and bone-crushing dogs (Borophaginae), as well as various species of fish, frog, vole and beaver. Hagerman Fossil Beds National Monument Hagerman Fossil Beds National Monument near Hagerman, Idaho, contains the largest concentration of Hagerman horse fossils in North America. The fossil
Hagerman Fossil Beds National Monument
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composed of small, stub-like spines. In overall appearance, the typical Entomaspidid is a near-circular, medallion-like trilobite. Entomaspididae is thought to represent the transition between the ancestral Ptychopariida, and the harpetids. Many researchers question the validity of Entompaspididae as a distinct family, and merge its genera into Harpetidae. Ulrich erected "Entomaspididae" to contain species of "Entomaspis" and "Hypothetica", from the Latest Cambrian or Earliest Ordovician of Utah. The first entomaspidids appear in the fossil record near the close of the Cambrian period in marine strata of Utah and China. They persist into the Early Ordovician before disappearing from the fossil record.
Entomaspididae
494385
used her finds, such as William Buckland and Roderick Murchison, who ended up with multiple fossil species named after them. The only person who did name a species after her during her lifetime was the Swiss-American naturalist, Louis Agassiz. In the early 1840s, he named two fossil fish species after her—"Acrodus anningiae", and "Belenostomus anningiae"—and another after her friend Elizabeth Philpot. Agassiz was grateful for the help the women had given him in examining fossil fish specimens during his visit to Lyme Regis in 1834. After her death, other species, including the ostracod "Cytherelloidea anningi", and two genera, the therapsid
Mary Anning
9653620
in evolutionary stagnation. Thus the fossil record of an evolutionary progression typically consists of species that suddenly appear, and ultimately disappear hundreds of thousands or millions of years later, without any change in external appearance. Graphically, these fossil species are represented by horizontal lines, whose lengths depict how long each of them existed. The horizontality of the lines illustrates the unchanging appearance of each of the fossil species depicted on the graph. During each species' existence new species appear at random intervals, each also lasting many hundreds of thousands of years before disappearing without a change in appearance. The degree
Koinophilia
3266157
to commercial fisheries. In reef aquariums, parasitic isopods can become a pest, endangering the fish and possibly injuring the aquarium keeper. Some members of the family Cirolanidae suck the blood of fish, and others, in the family Aegidae, consume the blood, fins, tail and flesh and can kill the fish in the process. The World Marine, Freshwater and Terrestrial Isopod Crustaceans database subdivides the order into eleven suborders: Isopods first appeared in the fossil record during the Carboniferous period of the Paleozoic some 300 million years ago. They were primitive, short-tailed members of the suborder Phreatoicidea. At that time, Phreatoicideans
Isopoda
10694368
was initially thought to be a single species, four known populations of the “species” in the southeastern United States may actually be three distinct species or taxa, each originating from a different area in Asia. "Monopterus albus" is placed in the class or subclass Actinopterygii. It arose from the Osteichthyes, the first bony fish, whose fossil record dates back to the Triassic period. In turn, the bony fish came from the Acanthodii class of bony and cartilaginous fish. The common name of "M. albus" is somewhat of a misnomer, as the Asian swamp eel is not an eel, "per se".
Asian swamp eel
397503
of evolution, the fossil record of an evolutionary progression typically consists of species that suddenly appear, and ultimately disappear, hundreds of thousands or millions of years later, without any change in external appearance. Graphically, these fossil species are represented by lines parallel with the time axis, whose lengths depict how long each of them existed. The fact that the lines remain parallel with the time axis illustrates the unchanging appearance of each of the fossil species depicted on the graph. During each species' existence new species appear at random intervals, each also lasting many hundreds of thousands of years before
Speciation
4227077
paleontological record of Cenozoic aquatic communities in North America and possibly the world, within the 50-million-year-old Green River Formation — the ancient lake bed. Fossils preserved — including fish, alligators, bats, turtles, dog-sized horses, insects, and many other species of plants and animals — suggest that the region was a low, subtropical, freshwater basin when the sediments accumulated, over about a 2 million-year period. During the Eocene this portion of Wyoming was a sub-tropical lake ecosystem. The Green River Lake System contained three ancient lakes, Fossil Lake, Lake Gosiute, and Lake Uinta. These lakes covered parts of southwest Wyoming, northeast
Fossil Butte National Monument
12425056
Ma), a fungal spike (originally thought to be an extraordinary abundance of fungal spores in sediments) formed, suggesting that fungi were the dominant life form at this time, representing nearly 100% of the available fossil record for this period. However, the relative proportion of fungal spores relative to spores formed by algal species is difficult to assess, the spike did not appear worldwide, and in many places it did not fall on the Permian–Triassic boundary. 65 million years ago, immediately after the Cretaceous–Paleogene extinction that famously killed off most dinosaurs, there is a dramatic increase in evidence of fungi, apparently
Fungus
760370
plants. Like all other vascular plants, the diploid sporophyte is the dominant phase or generation in the life cycle. The gametophytes of ferns, however, are very different from those of seed plants. They are free-living and resemble liverworts, whereas those of seed plants develop within the spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte typically consists of: Ferns first appear in the fossil record in the early Carboniferous period. By the Triassic, the first evidence of ferns related to several modern families appeared. The great fern radiation occurred in the late Cretaceous, when
Fern
1678849
soon after, the evolution of jaws. Late Ordovician-aged microfossils of what have been identified as scales of either acanthodians or "shark-like fishes", may mark Gnathostomata's first appearance in the fossil record. Undeniably unambiguous gnathostome fossils, mostly of primitive acanthodians, begin appearing by the early Silurian, and become abundant by the start of the Devonian. The group is traditionally a superclass, broken into three top-level groupings: Chondrichthyes, or the cartilaginous fish; Placodermi, an extinct clade of armored fish; and Teleostomi, which includes the familiar classes of bony fish, birds, mammals, reptiles, and amphibians. Some classification systems have used the term Amphirhina.
Gnathostomata
5844535
species. The various species of snakeheads differ greatly in size; dwarf snakeheads, such as "Channa gachua", do not surpass in length. Most other snakeheads reach between . Five species ("C. argus", "C. barca", "C. marulius", "C. micropeltes", and "C. striata") can reach or more. Snakeheads are thrust-feeders that consume plankton, aquatic insects, and mollusks when small. As adults, they mostly feed on other fish (such as carp) or on frogs. In rare cases, small mammals such as rats are eaten. The Channidae are well represented in the fossil record and known from numerous specimens. They likely originated in the south
Snakehead (fish)
2883868
early missionaries and explorers such as S. A. Parker, 1840, and J. C. Fremont, 1845. Geologist Dr. John Evans collected the first fossil fish, described as "Culpea humilis" (later renamed "Knightia eocaena"), from the Green River beds in 1856. Edward Drinker Cope collected extensively from the area and produced several publications on the fossil fish from 1870 onwards. Ferdinand Vandeveer Hayden (geologist-in-charge of the United States Geological and Geographical Survey of the Territories, the forerunner of the United States Geological Survey) first used the name "Green River Shales" for the fossil sites in 1869. Millions of fish fossils have been
Green River Formation
12596391
hypothesis for at least some of the rapid changes in life forms that appear in the fossil records. A very large number of fossils have now been discovered and identified. These fossils serve as a chronological record of evolution. The fossil record provides examples of transitional species that demonstrate ancestral links between past and present life forms. One such transitional fossil is "Archaeopteryx", an ancient organism that had the distinct characteristics of a reptile (such as a long, bony tail and conical teeth) yet also had characteristics of birds (such as feathers and a wishbone). The implication from such a
Introduction to evolution
19599111
at the same time the base of the Cisuralian series and the Permian system. It is defined as the place in the stratigraphic record where fossils of "Streptognathodus isolatus" first appear. The top of the Asselian stage (the base of the Sakmarian stage) is at the first appearance of conodont species "Streptognathodus postfusus". The Asselian contains five conodont biozones: The base of the Sakmarian stage is laid with the first appearance of "Streptognathodus postfusus" in the fossil record. The top of the Sakmarian (the base of the Artinskian) is defined as the place in the stratigraphic record where fossils of
Conodont biostratigraphy
711446
went through two major bottlenecks during the Late Devonian extinctions, also known as the end-Frasnian and end-Fammenian extinctions. These extinction events led to the disappearance of stem-tetrapods with fish-like features. When stem-tetrapods reappear in the fossil record in early Carboniferous deposits, some 10 million years later, the adult forms of some are somewhat adapted to a terrestrial existence. Why they went to land in the first place is still debated. During the early Carboniferous, the number of digits on hands and feet of stem-tetropods became standardized at no more than five, as lineages with more digits died out. By mid-Carboniferous
Tetrapod
19537447
sister group to the tetrapods (mammals, birds and reptiles, and amphibians). The extensive fossil record and numerous morphological and molecular studies have shown, however, that lungfish and some fossil lobe-finned fish are more closely related to tetrapods than they are to coelacanths; as a result tetrapods are nested within Sarcopterygii. This abides to cladistics in that in order for a clade to be monophyletic, it must have an ancestral species and all descendants of that common ancestor based on shared characteristics. As such mammals, birds and reptiles, and amphibians are highly derived lobe-finned fish despite looking nothing like the standard
Cladistic Classification of Class Sarcopterygii
17372109
in the US. These capsules are up to 5 cm in length and resemble those of modern catshark species in the genus "Apristurus". Since fossil teeth attributable to this genus go back to the late Eocene this, an ancient "Apristurus" species might very well be the mother of the fossil egg cases. A less likely candidate mother would be the genus "Scyliorhinus", which also has a fossil record stretching back to the Eocene. However, modern "Scyliorhinus" egg capsules are smoother than the Bear River Seep Deposit fossils, casting doubt on this possibility. Some well-preserved embryos have been found with yolk
Fish egg fossil
4807906
sing the theme song to the 1971 film "Shaft", "Theme from Shaft". The Fox network censors originally did not want the staff to use the song because they thought the lyrics were too obscene to appear on television. In order to prove the censors wrong and show that it could appear on television, the staff dug up footage from an old Academy Awards ceremony at which the song was performed by Isaac Hayes. When the chef of the sushi bar finds out that Homer has been poisoned, he yells at his apprentices in Japanese. The staff wanted the language they
One Fish, Two Fish, Blowfish, Blue Fish
1774540
found in a more advanced and complex form in the related cypriniform fish, such as carp. Also like the cypriniforms, the gonorynchiforms produce a substance from their skin when injured that dissolves into the water and acts an alarm signal to other fish. Although many of the families are rather small, there are several fossil genera. This listing of the groups of Gonorynchiformes includes fossil fish with a short description. They are listed in approximate order of how primitive their characteristics are. Gonorynchiformes The Gonorynchiformes are an order of ray-finned fish that includes the important food source, the milkfish ("Chanos
Gonorynchiformes
3941823
ciliated motion to move food, ostracoderms used their muscular pharynx to create a suction that pulled small and slow moving prey into their mouths. The first fossil fishes that were discovered were ostracoderms. The Swiss anatomist Louis Agassiz received some fossils of bony armored fish from Scotland in the 1830s. He had a hard time classifying them as they did not resemble any living creature. He compared them at first with extant armored fish such as catfish and sturgeons but later realizing that they had no movable jaws, classified them in 1844 into a new group "ostracoderms" which means "shell-skinned".
Ostracoderm
1662924
Tinamou Tinamous form an order of birds (Tinamiformes), comprising a single family (Tinamidae) with two distinct subfamilies, containing 47 species found in Mexico, Central America, and South America. The word "tinamou" comes from the Galibi term for these birds, "tinamu". Tinamous have traditionally been regarded as the sister group of the flightless ratites, but recent work places them well within the ratite radiation, implying basal ratites could fly. Tinamous first appear in the fossil record in the Miocene epoch. They are generally sedentary, ground-dwelling and, though not flightless, when possible avoid flight in favour of hiding or running away from
Tinamou
12590032
the discinoid genus "Pelagodiscus" have a cosmopolitan distribution. The rates of metabolism of Brachiopoda are between one third and one tenth of those of bivalves. While brachiopods were abundant in warm, shallow seas during the Cretaceous period, they have been outcompeted by bivalves, and now live mainly in cold and low-light conditions. Brachiopod shells occasionally show evidence of damage by predators, and sometimes of subsequent repair. Fish and crustaceans seem to find brachiopod flesh distasteful. The fossil record shows that drilling predators like gastropods attacked molluscs and echinoids 10 to 20 times more often than they did brachiopods, suggesting that
Brachiopod
15916744
Kyphosichthys Kyphosichthys is an extinct genus of basal actinopterygian bony fish known from the lower Middle Triassic (Anisian) marine deposits (Guanling Formation) in Luoping, eastern Yunnan Province, southwestern China. The species is the first known fossil record of highly deep-bodied Neopterygii ginglymodians. "Kyphosichthys" (Greek for "bent fish") has a strongly arched hump between the head and the dorsal fin, from which its name derives. The holotype measures 96 mm in total length, and 76 mm in standard length. The greatest body height occurs at the posterior opercular margin, where the body height is over 70% of the standard length. The
Kyphosichthys
7685321
flying squirrels have similar adaptations enabling their arboreal lifestyle; and the numbat and anteaters are both digging insectivores. Most of Australia's mammals are herbivores or omnivores. The fossil record shows that monotremes have been present in Australia since the Early Cretaceous . Marsupials probably existed in Australia at least from the early Paleocene (), although the earliest found undoubted fossils of Australian marsupials are from the late Oligocene . The indisputable remains of Australian placental mammals started from the Miocene, when Australia moved closer to Indonesia. After bats appeared reliably in the fossil record, and after rodents did. The subsequent
Mammals of Australia
13808318
other fauna we recovered from the rock matrix alongside the "Raptorex" fossil, we could generally pinpoint where it had been dug up in an area along the border with Inner Mongolia." However, only a single fish vertebra and a crushed, unidentifiable mollusk shell were actually present alongside the "Raptorex" specimen. Sereno and colleagues identified the fish vertebra as being similar to the genus "Lycoptera", a key index fossil of the early Cretaceous Yixian formation. However, they did not describe the bone or note any features in common with known "Lycoptera" specimens. Sereno's interpretation of the specimen as an early, primitive,
Raptorex
16560076
the relatively poor fossil record of Africa long before they appear in the fossil-rich deposits of Europe during the mid-Lutetian. This ancient stem lineage of lemuriform primates in Africa possibly descended from an early Asian branch of adapiforms such as a primitive branch of cercamoniines predating "Donrussellia" (one of the oldest European adapiforms). "Djebelemur martinezi" was first described in 1992 by Hartenberger and Marandat. The description was based on a lower jaw fragment and two isolated upper molars found in Tunisia at the Chambi locality, which date to the late early or early middle Eocene. It was described as an
Djebelemur
8678261
to this world from another, millions of years ago; explaining why species in the Quintaglios' fossil record appear suddenly rather than gradually. The book ends with Dybo declaring that the Quintaglios are not merely going to the stars; they are going home. Also complementing the main plot are the "Musings of the Watcher", interspersed through the book and told in flashback from the first person perspective of a god-like entity whose consciousness has survived from the previous cycle of creation. The Watcher was originally an extraterrestrial being that existed in the universe prior to the birth of the current one.
Fossil Hunter
4879544
naming the important fossil at the expense of his rival. However, Marsh did not initially recognize the true importance of the fossil. Soon after receiving it, he reported back to Mudge his opinion that the chalk slab contained the bones of two distinct animals: a small bird animal, and the toothed jaws of some unknown reptile. Marsh considered the unusual vertebrae of the bird to resemble those of a fish, so he named it "Ichthyornis", or "fish bird." Later in 1872, Marsh described the toothed jaws as a new species of marine reptile, named "Colonosaurus mudgei" after their discoverer. The
Ichthyornis
6656314
Abelisauridae Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous Period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian subcontinent and the island of Madagascar. Reports based on isolated teeth show the occurrence in the Late Jurassic of Portugal, and the confirmed existence of European Abelisaurids comes from the Late Cretaceous of France with "Arcovenator". Abelisaurids first appear in the fossil record of the early middle Jurassic period, and at
Abelisauridae
3408269
Archostemata The Archostemata are the smallest suborder of beetles, consisting of fewer than 50 known species organised into five families. They are an ancient lineage with a number of primitive characteristics. They are similar in morphology to the first beetles, which appear in the fossil record about 250 million years ago. Antennae may be thread-shaped (filiform) or like a string of beads (moniliform). This suborder also contains the only paedogenic beetles, "Micromalthus debilis". These beetles are considered rare. Fossil deposits from the Permian suggest that the Archostemata were once much more common and dispersed over a wide portion of the
Archostemata
7778687
kannemeyeriid dicynodonts doubtless constituted much of erythrosuchids' prey. However, the first erythrosuchids appear in the fossil record slightly earlier than the kannemeyeriids, so it must be assumed that they fed on other animals as well. Erythrosuchidae Erythrosuchidae (meaning "red crocodiles") are a family of large basal archosauriform carnivores that lived from the later Early Triassic (Olenekian) to the early Middle Triassic (Anisian). They were the apex predators of their day, with lengths of 2.5 to over 5 meters. Their fossil remains are known to date from South Africa (Beaufort Group of the Karoo Basin), China, and European Russia, from the
Erythrosuchidae
16939131
of the High Plains. There are very few rocks of Jurassic age in Texas. The only known Jurassic fossils of Texas come from the Malone Mountains which preserve ammonites, gastropods, and pelecypods. The Cretaceous, by contrast left a rich local fossil record. Due to the alternating rising and falling of local sea levels a variety of life from both land and sea would be preserved in its fossil record. Cretaceous vertebrate life of Texas included amphibians, birds, dinosaurs, fish, and reptiles. Almost a quarter of Texas is covered by Cretaceous rocks and are a good source of fossils. Most of
Paleontology in Texas
1762172
Lungfish Lungfish are freshwater rhipidistian fish belonging to the subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Today there are only six known species of lungfish, living only in Africa, South America and Australia. The fossil record show that lungfish were abundant since the Triassic. While vicariance would suggest this represents an ancient distribution limited to the Mesozoic supercontinent Gondwana, the fossil record suggests advanced lungfish had a widespread freshwater distribution and the
Lungfish
2064259
and birds, and their extinct relatives. Fossils of rhynchocephalians first appear in the Early Triassic, meaning that the lineage leading to squamates must have also existed at the time. Scientists believe crown group squamates probably originated in the Early Jurassic based on the fossil record. The first fossils of geckos, skinks and snakes appear in the Middle Jurassic. Other groups like iguanians and varanoids appeared in the Cretaceous. Polyglyphanodontians, a distinct clade of lizards, and mosasaurs, a group of predatory marine lizards that grew to enormous sizes, also appeared in the Cretaceous. Squamates suffered a mass extinction at the Cretaceous–Paleogene
Squamata
1271955
Redlichiida Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are "Fallotaspis" (suborder Olenellina), and "Lemdadella" (suborder Redlichiina), both belonging to this order. The first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. In terms of anatomical comparison, the earliest redlichiid
Redlichiida
4184049
in the fossil record in the early Carboniferous (the "Romer's gap") when most of the groups appear to have evolved. Further complicating the picture is the amphibian larval-adult life cycle, with physical changes throughout life complicating phylogenetic analysis. The Labyrinthodontia appear to be composed of several nested clades. The two best understood groups, the Ichthyostegalia and the reptile-like amphibians have from the outset been known to be paraphyletic. Tellingly, labyrinthodont systematics was the subject of the inaugural meeting of International Society for Phylogenetic Nomenclature. The early labyrinthodonts are known from the Devonian and possibly extending into the Romer's Gap of
Labyrinthodontia
19343232
overlapping each other, obscuring detail of the hindwing venation. Rafaelnymphes Rafaelnymphes is an extinct genus of lacewing in the family Nymphidae known from a fossil found in South America. The genus contains a single species, Rafaelnymphes cratoensis. When first described, "R. cratoensis" was known from a single fossil adult which is a compression-impression fossil preserved in layers of soft sedimentary rock. Along with other well-preserved insect fossils, the "R. cratoensis" specimen was collected from layers of the Upper Aptian Crato Formation. The formation is composed of unweathered grey and oxidized yellow limestones, which preserved numerous insects, fish, birds and reptiles
Rafaelnymphes
19343228
Rafaelnymphes Rafaelnymphes is an extinct genus of lacewing in the family Nymphidae known from a fossil found in South America. The genus contains a single species, Rafaelnymphes cratoensis. When first described, "R. cratoensis" was known from a single fossil adult which is a compression-impression fossil preserved in layers of soft sedimentary rock. Along with other well-preserved insect fossils, the "R. cratoensis" specimen was collected from layers of the Upper Aptian Crato Formation. The formation is composed of unweathered grey and oxidized yellow limestones, which preserved numerous insects, fish, birds and reptiles as a notable lagerstätten. The area is a preserved
Rafaelnymphes
19597651
"Streptognathodus postfusus". The Asselian contains five conodont biozones: The base of the Sakmarian stage is laid with the first appearance of "Streptognathodus postfusus" in the fossil record. A global reference profile for the base had in 2009 not yet been appointed. The top of the Sakmarian (the base of the Artinskian) is defined as the place in the stratigraphic record where fossils of conodont species "Sweetognathus whitei" and "Mesogondolella bisselli" first appear. Streptognathodus Streptognathodus is an extinct genus of conodonts from the Late Carboniferous to Early Permian. The top of the Kasimovian stage is close to the first appearance of
Streptognathodus
19530848
is the oldest known trace of bird eggs in the fossil record. At the Kitadani Formation, numerous other dinosaurs are known to have coexisted with "Plagioolithus", including "Fukuiraptor", "Fukuisaurus", "Fukuititan", "Koshisaurus", and an unidentified type of non-avian theropod. Also present were goniopholidid crocodiles, eucryptodire turtles, and amiiform fish. Footprints of various amphibians, dinosaurs, birds, and pterosaurs are known from the Kitadani Formation. Plagioolithus Plagioolithus is an oogenus of fossil egg. It is from the Early Cretaceous of Japan. It was probably laid by a bird, making it the oldest known fossil bird egg. "Plagioolithus" is most notable for having a
Plagioolithus
5703981
Hyperoartia Hyperoartia or Petromyzontida is a disputed group of vertebrates that includes the modern lampreys and their fossil relatives. Examples of hyperoartians from early in their fossil record are "Endeiolepis" and "Euphanerops" (which possessed a calcified branchial basket), fish-like animals with hypocercal tails that lived during the Late Devonian Period. Some paleontologists still place these forms among the "ostracoderms" (jawless armored fishes) of the class Anaspida, but this is increasingly considered an artificial arrangement based on ancestral traits. Placement of this group among the jawless vertebrates is a matter of dispute. While today enough fossil diversity is known to make
Hyperoartia
16939345
sharks, makos, tiger sharks, white sharks, and an archaic basking shark. Bony fish included mahi mahi, conger eels, rattails, ancestral billfish, cod, hake, and rockfish. Marine birds in the area included auks, the local species "Hydrotherikornis oregonus", and the pelican-like "Phocavis maritimus." The state's only known fossil egg was found in associated rock formations. The subduction zone's volcanic activity also formed the Cascade volcanic arc, which blocked moist air from the Pacific and created the state's High Desert. This is when Oregon's fossil-rich John Day Fossil Beds were first laid down. The earliest fossils in John Day indicate a subtropical
Paleontology in Oregon
19300658
Makarkinia Makarkinia is an extinct genus of lacewing in the family Kalligrammatidae described by Martins-Neto in 1997 from a fossil found in South America. The genus contains two species dating from the Cretaceous, Makarkinia adamsi and Makarkinia kerneri. When first described, "Makarkinia" was known from a single fossil wing which is a compression-impression fossil preserved in layers of soft sedimentary rock. Along with other well-preserved insect fossils, the "Makarkinia" specimens were collected from layers of the Upper Aptian Crato Formation. The formation is composed of unweathered grey and oxidized yellow limestones, which preserved numerous insects, fish, birds and reptiles as
Makarkinia
13323372
Opsithrissops Opsithrissops (Ancient Greek: "Aspect Fish Face") is an extinct genus of prehistoric bony fish that lived during the Thanetian stage of the Paleocene epoch. It is a small nektonic opportunistic carnivore in the family Osteoglossiformes which includes other bony-tongues such as the extant species of Arowana and Arapaima. It hunted small invertebrates and fish similarly to today's trout and became a Paleogene keystone species in many habitats before its disappearance from the fossil record. Despite being part of the same family as more basal and primitive bony fish like the Arowana, the "Opsithrissops" had a body that was built
Opsithrissops
13835880
oldest and most basal one known, surpassing "Raranimus" in age by several million years. However, later studies have questioned the placement of "Tetraceratops" within Therapsida, and the 2009 phylogenetic analysis using "Raranimus" places the genus outside of the clade. "Raranimus" occurs in strata that were deposited during the early Roadian stage of the Middle Permian. The sphenacodontids were most diverse before the Roadian in the Early Permian, yet therapsids did not appear as a diverse group until near the Roadian-Wordian boundary. This has left a morphological and temporal gap in the fossil record during which the origin of therapsids must
Raranimus
4694320
were the fossil remains of a large fish; ""Pterygotus"" translating to "winged fish". The specimens described by Agassiz from England were referred to a species he dubbed "Pterygotus problematicus". Agassiz first recognized the true nature of the fossils as arthropod remains five years later in 1844 after having examined more complete fossils recovered in the Old Red Sandstone of Scotland. Although recognizing the fossils of "Pterygotus" as arthropod was closer to its modern phylogenetical position, Agassiz would consider "Pterygotus" to represent a crustacean of the Entomostraca subclass. Although Frederick M'Coy did note that "Pterygotus" resembled the Limulidae and the previously
Pterygotus
966829
condyle of the humerus was not angled at 20°–30° away from long axis of the humerus. The analysis did not result in a phylogenetic pattern but rather grouped some birds with similar wing shapes together while others stood separate. It is thus unknown whether this apparent similarity to grebes represents an evolutionary relationship, or whether "Telmatornis" simply had a wing similar to that of grebes and moved it like they do. True grebes suddenly appear in the fossil record in the Late Oligocene or Early Miocene, around 23–25 mya. While there are a few prehistoric genera that are now completely
Grebe
6341537
geologic timescale. The base of the Sakmarian stage is laid with the first appearance of conodont species "Streptognathodus postfusus" in the fossil record. A global reference profile for the base (a GSSP) had in 2009 not yet been appointed. The top of the Sakmarian (the base of the Artinskian) is defined as the place in the stratigraphic record where fossils of conodont species "Sweetognathus whitei" and "Mesogondolella bisselli" first appear. Sakmarian In the geologic timescale, the Sakmarian is an age or stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Sakmarian lasted between and
Sakmarian
16945738
ostracoderms used their gills for respiration only. They had up to eight separate pharyngeal gill pouches along the side of the head, which were permanently open with no protective operculum. Unlike invertebrates that use ciliated motion to move food, ostracoderms used their muscular pharynx to create a suction that pulled small and slow moving prey into their mouths. The first fossil fishes that were discovered were ostracoderms. The Swiss anatomist Louis Agassiz received some fossils of bony armored fish from Scotland in the 1830s. He had a hard time classifying them as they did not resemble any living creature. He
Evolution of fish
14044543
an increase in unarmored vertebrates as well as a growth in fish size and the increased migration of fish into marine environments. The Devonian would also see the evolution of significantly faster-moving fish and the evolution of proper jaws. These adaptations, potentially a result of pterygotid predation, would have significantly affected the likelihood of fish representing pterygotid prey and larger predatory fish may even have begun preying on pterygotids and other eurypterids, contributing to their decline and extinction. The arguments of Romer were based on evolutionary trends in both groups and the fossil co-occurrences of both groups but he did
Pterygotidae
20042426
could have been a pathway for life to propagate between these water systems, a notion supported by fish fossil data such as the minnows and suckerfish of the Death Valley system which appear to originate in Lake Lahontan. Lake Lahontan might have drained into Lake Manly; one potential pathway would be from the Walker Lake basin over Soda Springs Valley, Fish Lake Valley and Eureka Valley where it may have been joined by overflow from Deep Springs Valley. All these valleys are at successively lower elevations. Connections to the Colorado River also existed: There is evidence that the Amargosa River
Lake Manly