During the time of the deposition of the Niobrara Chalk, much life inhabited the seas of the Western Interior Seaway. By this time in the Late Cretaceous many new lifeforms appeared such as mosasaurs, which were to be some of the last of the aquatic lifeforms to evolve before the end of the Mesozoic. Life of the Niobrara Chalk is comparable to that of the Dakota Formation, although the Dakota Formation, which was deposited during the Cenomanian, predates the chalk by about 10 million years.
Color | Explanation |
---|---|
Light grey | A "regular" taxon which the scientific consensus does not regard as a dubious, synonymous, undescribed, or otherwise taxonomically questionable name. |
Dark grey | A taxon or parataxon that is misidentified, dubious, synonymous, undescribed, or otherwise taxonomically questionable name. |
Peach | An ichnotaxon, a parataxon representing a specific kind of trace fossil. |
Light blue | An ootaxon, a parataxon representing a specific kind of fossil egg. |
Light green | A morphotaxon, a parataxon representing a single stage or anatomical part of a plant or plant-like organism. Examples include fossil pine cones, fungal spores, and leaves. |
Genus | Species | Member | Abundance | Notes |
---|---|---|---|---|
Micropycnodon [1] | M. kansasensis [1] | Smoky Hill Chalk [1] | A pycnodontiform fish similar but unrelated to modern parrotfish |
Genus | Species | Member | Abundance | Notes |
---|---|---|---|---|
H. marshi [1] | Smoky Hill Chalk [1] | Family Hadrodontidae Thurmond and Jones 1981 |
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Protosphyraena [1] | P. bentonianum | A swordfish-like pachycormid | |||
P. nitida [1] | Smoky Hill Chalk [1] | ||||
P. perniciosa [1] | Smoky Hill Chalk [1] | ||||
P. tenuis [1] | Smoky Hill Chalk [1] | ||||
P. gladius [1] | Smoky Hill Chalk [1] | Named as a new genus, Bonnerichthys | |||
Bonnerichthys [2] | B. gladius | Smoky Hill Chalk [3] | A filter feeding pachycormid |
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Apsopelix [3] | A. anglicus [3] | Smoky Hill Chalk [3] | A crossognathid. | ||
Pachyrhizodus [3] | P. caninus [3] | Smoky Hill Chalk [3] | A pachyrhizodontid | ||
P. leptopsis [3] | Smoky Hill Chalk [3] | ||||
P. minimus [3] | Smoky Hill Chalk [3] | ||||
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Xiphactinus [3] | X. audax [3] | Smoky Hill Chalk [3] | A large ichthyodectid | ||
Ichthyodectes [3] | I. ctenodon [3] | Smoky Hill Chalk [3] | An ichthyodectid | ||
Gillicus [3] | G. arcuantus [3] | Smoky Hill Chalk [3] | A saurodontid | ||
Saurodon [3] | S. leanus [3] | Smoky Hill Chalk [3] | A saurodontid | ||
Saurocephalus [3] | S. lanciformis [3] | Smoky Hill Chalk [3] | A saurodontid |
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Thryptodus [3] | T. zitteli [3] | Smoky Hill Chalk [3] | A plethodid | ||
Pentanogmius [3] | P. evolutus [3] | Smoky Hill Chalk [3] | A plethodid | ||
Martinichthys [3] | M. brevis [3] | Smoky Hill Chalk [3] | A plethodid | ||
M. xiphoides [3] | Smoky Hill Chalk [3] | ||||
Niobrara [3] | N. encarsia [3] | Smoky Hill Chalk [3] | A plethodid | ||
Zanclites [3] | Z. xenurus [3] | Smoky Hill Chalk [3] | A plethodid | ||
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Cimolichthys [3] | C. nepaholica [3] | Smoky Hill Chalk [3] | A cimolichthyid | ||
E. dirus [3] | Smoky Hill Chalk [3] | An enchodontid | |||
E. gladiolus [3] | Smoky Hill Chalk [3] | ||||
E. petrosus [3] | Smoky Hill Chalk [3] | ||||
E. shumardi [3] | Smoky Hill Chalk [3] | ||||
Apateodus [3] | Indeterminate [3] | Smoky Hill Chalk [3] | An alepisauriform actinopterygiian related to the modern lancetfish and lizardfish | ||
Stratodus [3] | S. apicalis [3] | Smoky Hill Chalk [3] | An alepisauriform actinopterygiian | ||
Leptecodon [3] | L. rectus[ citation needed ] | An alepisauriform actinopterygiian |
Genus | Species | Member | Abundance | Notes |
---|---|---|---|---|
Kansius [3] | K. sternbergi [3] | Smoky Hill Chalk [3] | A beryciform actinopterygiian | |
Trachichthyoides [3] | Indeterminate [3] | Smoky Hill Chalk [3] | A beryciform actinopterygiian | |
Caproberyx [3] | Indeterminate [3] | Smoky Hill Chalk [3] | A beryciform actinopterygiian |
Genus | Species | Member | Abundance | Notes |
---|---|---|---|---|
Indeterminate [1] | Smoky Hill Chalk [1] | A lepisosteid gar | ||
Paraliodesmus [3] | P. guadagnii [3] | Smoky Hill Chalk [3] | An amiiform | |
Urenchelys [3] | U. abditus [3] | Smoky Hill Chalk [3] | An anguilliform | |
Ferrifrons | F. rugosus | A ferrifronsid acanthomorph | ||
Aethocephalichthys [3] | A. hyainarhinos [3] | Smoky Hill Chalk [3] | An actinopterygian of indeterminate classification [4] | |
Omosoma | O. garretti | A polymixiid actinopterygiian closely related to the modern Beardfish | ||
Belonostomus [1] | Indeterminate [1] | An aspidorhynchid |
Fish are by far the most common fossils found from the formation, with remains of prehistoric sharks, ray-finned fishes, and lobe-finned fishes in abundance. As well as smaller fish, many large predatory fish were present in the seas at that time, most notably Xiphactinus . Several fish were of close relation to modern day fish including primitive coelacanths, slime heads, lancetfish, gars, swordfish, and salmonids.
Genus | Species | State | Member | Abundance | Notes | Images |
---|---|---|---|---|---|---|
C. mantelli [5] | Smoky Hill Chalk [5] | A large lamniform shark | ||||
C. appendiculata [6] | Smoky Hill Chalk [6] | A lamniform shark | ||||
C. appendiculata [5] | N/A | N/A | N/A | An extremely widely used lapsus calami for Cretalamna . [7] | ||
Johnlongia [5] | Indeterminate [5] | Smoky Hill Chalk [5] | An odontaspidid lamniform shark | |||
Pseudocorax [5] | P. laevis [5] | Smoky Hill Chalk [5] | A lamniform shark smaller than Cretoxyrhina | |||
Squalicorax [5] | S. falcatus [5] | Smoky Hill Chalk [5] | A lamniform | |||
S. kaupi [5] | Smoky Hill Chalk [5] | |||||
S. pristodontus [5] | Smoky Hill Chalk [5] | |||||
Scapanorhynchus [5] | S. raphiodon [5] | Smoky Hill Chalk [5] | A mitsukurinid shark similar in appearance to the modern day goblin shark | |||
Ptychodus [5] | P. anonymus [5] | Smoky Hill Chalk [5] | A ptychodontid hybodontoid shark | |||
P. martini [5] | Smoky Hill Chalk [5] | |||||
P. mortoni [5] | Smoky Hill Chalk [5] | |||||
P. occidentalis [5] | Smoky Hill Chalk [5] | |||||
P. polygyrus [5] | Smoky Hill Chalk [5] |
Genus | Species | State | Member | Abundance | Notes | Images |
---|---|---|---|---|---|---|
E. laqueatus[ citation needed ] | A callorhinchid chimaeriform related to the modern ratfish | |||||
Rhinobatos [5] | R. incertus [5] | Smoky Hill Chalk [5] |
Nonavian dinosaurs have been found in the Niobrara Chalk despite it being located hundreds of miles out to sea at the time. The most reasonable theory is that the carcasses drifted out to sea. It is unlikely that the bodies were carried out by outgoing tides along the shorelines where they died, but rather it is more probable that the dinosaurs were carried offshore by floodwaters during a storm. In the shallow waters the bodies would have begun to decompose and bacteria within the carcass would have produced gasses that would have accumulated in the gut, thereby making the body buoyant. Next, the prevailing winds and currents would have carried it out to sea, where it would eventually settle to the bottom and be buried in sediment. [8]
A few caudal vertebrae from a hadrosaur have been found with bite marks and have been eroded, suggesting at one point they were digested. A single tooth belonging to Squalicorax was found in situ under the vertebrae. This suggested the shark consumed the posterior end of the tail of a floating hadrosaur carcass and had partially digested it before fossilization. [9] [10] Most dinosaurs in the chalk were nodosaurs. The dinosaurs found here were endemic to Appalachia. [11]
Genus | Species | State | Member | Material | Notes | Images |
---|---|---|---|---|---|---|
C. agilis [12] | Kansas [13] | Smoky Hill Chalk [12] | "Single articulated postcranial skeleton with associated skull fragments." [14] | A small hadrosaurid | ||
Indeterminate hadrosaurid [15] | A hadrosaurid of indeterminate classification. Possibly Corythosaurus. [15] | |||||
N. coleii [12] | Kansas [13] | Smoky Hill Chalk [12] | "Partial skeleton." [16] | A nodosaurid ankylosaur. | ||
Hierosaurus [12] | H. sternbergi [12] | Kansas [13] | Smoky Hill Chalk [12] | "Osteoderms." [17] | A nodosaurid ankylosaur. |
Three genre of birds are present in the formation, although rare. They were unrelated to modern birds, as they still retained teeth. Baptornis and Hesperornis were large flightless aquatic birds suited for diving. Ichthyornis was a seabird that resembled the gulls and petrels of today. Both probably preyed on small fish and were preyed upon by sharks, large bony fish such as Xiphactinus , and mosasaurs.
Genus | Species | State | Member | Material | Notes | Images |
---|---|---|---|---|---|---|
Apatornis [18] | A. celer [18] | Smoky Hill Chalk [18] | "Postcranial elements." [20] | |||
Baptornis [18] | B. advenus [18] | Smoky Hill Chalk [18] | "Fragmentary skull [and] nearly complete postcranium." [21] | A baptornithid hesperornithiform | ||
Guildavis [18] | G. tener [18] | Smoky Hill Chalk [18] | ||||
H. crassipes [13] | Kansas [13] | "Partial postcranial skeleton." [21] | ||||
H. gracilis [13] | Kansas [13] | "Tarsometatarsus." [21] | ||||
H. regalis [18] | Kansas [13] | Smoky Hill Chalk [18] | A large hesperornithid hesperornithiform | |||
Iaceornis [18] | I. marshi [18] | Smoky Hill Chalk [18] | ||||
I. agilis [13] | Kansas [13] | Junior synonym of I. dispar. [13] | ||||
I. anceps [13] | Kansas [13] | Junior synonym of I. dispar. [13] | ||||
I. dispar [18] | Kansas [13] | Smoky Hill Chalk [18] | An ichthyornithid | |||
I. lentus [13] | Kansas [13] | |||||
I. tener [13] | Kansas [13] | |||||
I. validus [13] | Kansas [13] | Junior synonym of I. dispar. [13] | ||||
I. victor [13] | Kansas [13] | Junior synonym of I. dispar. [13] | ||||
Parahesperornis [18] | P. alexi [18] | Kansas [13] | Smoky Hill Chalk [18] | "Partial skull [and] complete postcranium." [21] |
Clams, oysters, crinoids, ammonites, and squid are all common in the Niobrara Chalk and must have constituted the majority of life at the time. Evidence of sponges, annelid worms, and crustaceans are less common and are usually found as trace fossils.
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
C. undulatoplicatus [22] | Smoky Hill Chalk [22] | ||||
D. maxima [22] | Smoky Hill Chalk [22] | ||||
Fort Hays Limestone [23] | |||||
Fort Hays Limestone [23] | |||||
Ostrea [23] | Fort Hays Limestone [23] | ||||
P. platinus [22] | Smoky Hill Chalk [22] | ||||
P. congesta [22] | Smoky Hill Chalk [22] | ||||
V. grandis [22] | Smoky Hill Chalk [22] |
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
Smoky Hill Chalk [22] | |||||
Clioscaphites [22] | Smoky Hill Chalk [22] | ||||
Rugaptychus [22] | Smoky Hill Chalk [22] | ||||
Spinaptychus [22] | Smoky Hill Chalk [22] | ||||
Tusoteuthis [22] | T. longa | Smoky Hill Chalk [22] | A nomen dubium. [24] | ||
Enchoteuthis | E. melanae | Smoky Hill Chalk | Most material formerly referred to Tusoteuthis now belongs to this taxon. [24] | ||
E. cobbani | Smoky Hill Chalk | ||||
Niobrarateuthis | N. bonneri | Smoky Hill Chalk |
Genus | Species | State | Member | Abundance | Notes |
---|---|---|---|---|---|
"Unitacrinus" [22] | "U. socialis" [22] | N/A | N/A | N/A | Common lapsus calami of Uintacrinus |
Uintacrinus |
Mosasaurs are the most common marine reptiles in the Niobrara Chalk and the most successful ones in the sea at the time. Several different genera representing the four different subfamilies of Mosasauridae: the Tylosaurinae, Plioplatecarpinae, Mosasaurinae, and Halisaurinae, were present in Niobrara. They were the dominant carnivorous marine reptiles and ate cephalopods, fish, turtles, pterosaurs, birds, and even plesiosaurs. [26] There is evidence of them consuming other smaller mosasaurs. Despite this, mosasaurs often fell prey to some of the large sharks at the time, such as Cretoxyrhina . [27]
The presence of young mosasaurs in the formation suggests that mosasaurs were viviparous and gave birth hundreds of miles out to sea, as Niobrara was in the middle of the Western Interior Seaway at the time. [28] Juveniles would likely have been vulnerable to predation by the many large mid-ocean predators present in the ecosystem.
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
C. liodontus [29] | Smoky Hill Chalk [29] | ||||
C. prophython [29] | Smoky Hill Chalk [29] | ||||
E. clidastoides [30] | Smoky Hill Chalk [30] | ||||
E. everhartorum [31] | Smoky Hill Chalk | ||||
E. tlemonectes [32] | Smoky Hill Chalk | ||||
Eonatator | E. sternbergii | Smoky Hill Chalk [29] | A small halisaurine | ||
Platecarpus [30] | P. tympaniticus [30] | Smoky Hill Chalk [30] | A plioplatecarpine | ||
Plesioplatecarpus | P. planifrons [30] | Smoky Hill Chalk [30] | |||
T. nepaeolicus [30] | Smoky Hill Chalk [30] | A large tylosaurine, with the largest T. proriger reaching about 13 metres in length. | |||
T. proriger [30] | Smoky Hill Chalk [30] | ||||
Selmasaurus [33] | S. johnsoni | Smoky Hill Chalk |
Plesiosaurs are present from two different families within Plesiosauroidea in the Niobrara Chalk: the Polycotylidae, or short-necked plesiosaurs, and the Elasmosauridae, or long-necked plesiosaurs. Polycotylids superficially resemble pliosaurs, which are not present within the formation, but are unrelated. They were fast swimmers, unlike the Elasmosaurs that used their long necks to catch fish. [34] Plesiosaurs are rare in the formation and were therefore likely uncommon in the Western Interior Seaway at the time. Specimens become much more numerous in the Pierre Shale situated above the chalk.
Genus | Species | State | Member | Time span | Notes | Images |
---|---|---|---|---|---|---|
P. latipinnis [35] | Smoky Hill Chalk [35] | 84.5-81.5 Ma ago [36] | A polycotylid. | |||
Dolichorhynchops [35] | D. osborni [35] | Smoky Hill Chalk [35] | 84.5-81.5 Ma ago [36] | A polycotylid. also present in the Pierre Shale Formation | ||
Brimosaurus [37] | B. grandis | Kansas [37] | Fort Hays Limestone [37] | A nomen dubium. | ||
Styxosaurus [35] | S. snowii [35] | Smoky Hill Chalk [35] | 85-81.5 Ma ago [36] | A large elasmosaurid, also present in the Pierre Shale Formation | ||
Elasmosaurus [35] | "E." sternbergi [35] | Smoky Hill Chalk [35] | 84.5-81.5 Ma ago | Most likely not referable to Elasmosaurus. |
Two genre of pterosaurs are present in the formation, both within Pterodactyloidea: the pteranodontid Pteranodon (sometimes broken into several genera like Geosternbergia and Dawndraco , though this is dubious) and the nyctosaurid Nyctosaurus . They are large pterosaurs with elongated cranial crests. The pterosaurs of Niobrara probably spent most of their time at sea and rarely went on land, with Nyctosaurus being a probably fully pelagic animal. Pteranodon probably foraged on the ocean surface, while Nyctosaurus was a frigatebird-like aerial predator. [38]
Genus | Species | Member | Time span | Notes | Images |
---|---|---|---|---|---|
N. gracilis [39] | Smoky Hill Chalk [39] | 85–84.5 Ma ago [36] | A nyctosaurid ornithocheiroid. | ||
P. longiceps [39] | Smoky Hill Chalk [39] | 86–84.5 Ma ago [36] | A large and very abundant pteranodontid ornithocheiroid. | ||
G. sternbergi | Smoky Hill Chalk | 86–84.5 Ma ago | A species of Pterosaur that is regarded by a few Paleontologists to be a species of Pteranodon, though most regard it as a distinct species. | ||
Sea turtles have been found from the Niobrara Chalk that reached large sizes. The biggest, Archelon , was considerably larger than its distant relative, the leatherback sea turtle, which is the largest of the sea turtles alive today. The sea turtles most likely fed on ammonites, squid, and other cephalopods.
Genus | Species | Member | Abundance | Notes | Images |
---|---|---|---|---|---|
B. barberi [41] | Smoky Hill Chalk [41] | ||||
Chelosphargis [41] | C. advena [41] | Smoky Hill Chalk [41] | |||
C. stenopora [41] | Smoky Hill Chalk [41] | ||||
Porthochelys [41] | P. laticeps [41] | Smoky Hill Chalk [41] | A toxichelid cryptodire | ||
Protostega [41] | P. gigas [41] | Smoky Hill Chalk [41] | A protostegid cryptodire | ||
Toxochelys [41] | T. latiremis [41] | Smoky Hill Chalk [41] | A chelonioid cryptodire |
Pteranodon ; from Ancient Greek πτερόν and ἀνόδων is a genus of pterosaur that included some of the largest known flying reptiles, with P. longiceps having a wingspan of over 6 m (20 ft). They lived during the late Cretaceous geological period of North America in present-day Kansas, Nebraska, Wyoming, South Dakota and Alabama. More fossil specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway.
Plesiosauroidea is an extinct clade of carnivorous marine reptiles. They have the snake-like longest neck to body ratio of any reptile. Plesiosauroids are known from the Jurassic and Cretaceous periods. After their discovery, some plesiosauroids were said to have resembled "a snake threaded through the shell of a turtle", although they had no shell.
Tylosaurus is a genus of mosasaur, a large, predatory marine reptile closely related to modern monitor lizards and to snakes, from the Late Cretaceous.
Selmasaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Two species are known, S. russelli and S. johnsoni; both are exclusively known from Santonian deposits in the United States.
The Tylosaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tylosaurines" and have been recovered from every continent except for South America. The subfamily includes the genera Tylosaurus, Taniwhasaurus, and Kaikaifilu, although some scientists argue that only Tylosaurus and Taniwhasaurus should be included.
Protosphyraena is a fossil genus of swordfish-like marine fish, that thrived worldwide during the Upper Cretaceous Period (Coniacian-Maastrichtian). Though fossil remains of this taxon have been found in both Europe and Asia, it is perhaps best known from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas. Protosphyraena was a large fish, averaging 2–3 metres in length. Protosphyraena shared the Cretaceous oceans with aquatic reptiles, such as mosasaurs and plesiosaurs, as well as with many other species of extinct predatory fish. The name Protosphyraena is a combination of the Greek word protos ("early") plus Sphyraena, the genus name for barracuda, as paleontologists initially mistook Protosphyraena for an ancestral barracuda. Recent research shows that the genus Protosphyraena is not at all related to the true swordfish-family Xiphiidae, but belongs to the extinct family Pachycormidae.
Nyctosaurus is a genus of nyctosaurid pterosaur from the Late Cretaceous period of what is now the Niobrara Formation of the mid-western United States, which, during the time Nyctosaurus was alive, was covered in an extensive shallow sea. Some remains belonging to a possible Nyctosaurus species called N.lamegoi have been found in Brazil, making Nyctosaurus more diverse. The genus Nyctosaurus has had numerous species referred to it, though how many of these may actually be valid requires further study. At least one species possessed an extraordinarily large antler-like cranial crest.
Dolichorhynchops is an extinct genus of polycotylid plesiosaur from the Late Cretaceous of North America, containing the species D. osborni and D. herschelensis, with two previous species having been assigned to new genera. Dolichorhynchops was a prehistoric marine reptile. Its Greek generic name means "long-nosed face". While typically measuring about 3 metres (9.8 ft) in length, the largest specimen of D. osborni is estimated to have a total body length more than approximately 4.29 metres (14.1 ft).
The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear Paw Mountains in Montana. It includes a wide range of marine fossils, as well as the remains of a few dinosaurs. It is known for its fossil ammonites, some of which are mined in Alberta to produce the organic gemstone ammolite.
Styxosaurus is a genus of plesiosaur of the family Elasmosauridae. Styxosaurus lived during the Campanian age of the Cretaceous period. Three species are known: S. snowii, S. browni, and S. rezaci.
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico.
The Mooreville Chalk is a geological formation in North America, within the U.S. states of Alabama and Mississippi, which were part of the subcontinent of Appalachia. The strata date back to the early Santonian to the early Campanian stage of the Late Cretaceous. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment. It is a unit of the Selma Group and consists of the upper Arcola Limestone Member and an unnamed lower member. Dinosaur, mosasaur, and primitive bird remains are among the fossils that have been recovered from the Mooreville Chalk Formation.
The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological formation, known primarily for its exceptionally well-preserved marine reptiles. Named for the Smoky Hill River, the Smoky Hill Chalk Member is the uppermost of the two structural units of the Niobrara Chalk. It is underlain by the Fort Hays Limestone Member; and the Pierre Shale overlies the Smoky Hill Chalk. The Smoky Hill Chalk outcrops in parts of northwest Kansas, its most famous localities for fossils, and in southeastern Nebraska. Large well-known fossils excavated from the Smoky Hill Chalk include marine reptiles such as plesiosaurs, large bony fish such as Xiphactinus, mosasaurs, flying reptiles or pterosaurs, flightless marine birds such as Hesperornis, and turtles. Many of the most well-known specimens of the marine reptiles were collected by dinosaur hunter Charles H. Sternberg and his son George. The son collected a unique fossil of the giant bony fish Xiphactinus audax with the skeleton of another bony fish, Gillicus arcuatus inside the larger one. Another excellent skeleton of Xiphactinus audax was collected by Edward Drinker Cope during the late nineteenth century heyday of American paleontology and its Bone Wars.
Angolasaurus is an extinct genus of mosasaur. Definite remains from this genus have been recovered from the Turonian and Coniacian of Angola, and possibly the Coniacian of the United States, the Turonian of Brazil, and the Maastrichtian of Niger. While at one point considered a species of Platecarpus, recent phylogenetic analyses have placed it between the (then) plioplatecarpines Ectenosaurus and Selmasaurus, maintaining a basal position within the plioplatecarpinae.
The Carlile Shale is a Turonian age Upper/Late Cretaceous series shale geologic formation in the central-western United States, including in the Great Plains region of Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, and Wyoming.
Paleontology in New Jersey refers to paleontological research in the U.S. state of New Jersey. The state is especially rich in marine deposits.
Paleontology in Iowa refers to paleontological research occurring within or conducted by people from the U.S. state of Iowa. The paleozoic fossil record of Iowa spans from the Cambrian to Mississippian. During the early Paleozoic Iowa was covered by a shallow sea that would later be home to creatures like brachiopods, bryozoans, cephalopods, corals, fishes, and trilobites. Later in the Paleozoic, this sea left the state, but a new one covered Iowa during the early Mesozoic. As this sea began to withdraw a new subtropical coastal plain environment which was home to duck-billed dinosaurs spread across the state. Later this plain was submerged by the rise of the Western Interior Seaway, where plesiosaurs lived. The early Cenozoic is missing from the local rock record, but during the Ice Age evidence indicates that glaciers entered the state, which was home to mammoths and mastodons.
Paleontology in Nebraska refers to paleontological research occurring within or conducted by people from the U.S. state of Nebraska. Nebraska is world-famous as a source of fossils. During the early Paleozoic, Nebraska was covered by a shallow sea that was probably home to creatures like brachiopods, corals, and trilobites. During the Carboniferous, a swampy system of river deltas expanded westward across the state. During the Permian period, the state continued to be mostly dry land. The Triassic and Jurassic are missing from the local rock record, but evidence suggests that during the Cretaceous the state was covered by the Western Interior Seaway, where ammonites, fish, sea turtles, and plesiosaurs swam. The coasts of this sea were home to flowers and dinosaurs. During the early Cenozoic, the sea withdrew and the state was home to mammals like camels and rhinoceros. Ice Age Nebraska was subject to glacial activity and home to creatures like the giant bear Arctodus, horses, mammoths, mastodon, shovel-tusked proboscideans, and Saber-toothed cats. Local Native Americans devised mythical explanations for fossils like attributing them to water monsters killed by their enemies, the thunderbirds. After formally trained scientists began investigating local fossils, major finds like the Agate Springs mammal bone beds occurred. The Pleistocene mammoths Mammuthus primigenius, Mammuthus columbi, and Mammuthus imperator are the Nebraska state fossils.
Paleontology in Kansas refers to paleontological research occurring within or conducted by people from the U.S. state of Kansas. Kansas has been the source of some of the most spectacular fossil discoveries in US history. The fossil record of Kansas spans from the Cambrian to the Pleistocene. From the Cambrian to the Devonian, Kansas was covered by a shallow sea. During the ensuing Carboniferous the local sea level began to rise and fall. When sea levels were low the state was home to richly vegetated deltaic swamps where early amphibians and reptiles lived. Seas expanded across most of the state again during the Permian, but on land the state was home to thousands of different insect species. The popular pterosaur Pteranodon is best known from this state. During the early part of the Cenozoic era Kansas became a savannah environment. Later, during the Ice Age, glaciers briefly entered the state, which was home to camels, mammoths, mastodons, and saber-teeth. Local fossils may have inspired Native Americans to regard some local hills as the homes of sacred spirit animals. Major scientific discoveries in Kansas included the pterosaur Pteranodon and a fossil of the fish Xiphactinus that died in the act of swallowing another fish.
This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like Pteranodon and Hesperornis.