Dinosaurs From the Cenomanian to the Maastrichtian, Appalachia was inhabited by various groups of dinosaurs, including
hadrosauroids,
hadrosaurs,
nodosaurs,
leptoceratopsians,
indeterminate ornithopods,
tyrannosauroids,
dromaeosaurs,
ornithomimids, and
indeterminate maniraptors. There is also plausible fossil evidence of
chasmosaurs,
lambeosaurs,
sauropods,
carcharodontosaurs,
caenagnathids,
troodontids, and
coelurosaurs that might have inhabited the area. In 2022, fossils unearthed from the Woodbine Formation in Texas confirmed that carcharodontosaurs, troodontids, and coelurosaurs did indeed inhabit Appalachia.
Tyrannosaurs In Late Cretaceous North America, the dominant predators were the
Tyrannosauroidea, huge predatory
theropods built for ripping flesh from their prey. In Appalachia,
dryptosaurs were the top predators in this clade. Rather than developing the huge heads and massive bodies of their western relatives such as
Gorgosaurus,
Albertosaurus and
Lythronax, dryptosaurs had more in common with the basal tyrannosaurs like
Dilong and
Eotyrannus. Dryptosaurs were characterized by long arms with three fingers; while they were not as large as the largest tyrannosaurids, fossils from the Potomac Formation in New Jersey show that some of them did evolve some of the large-bodied features that can be found on other tyrannosaurs. Three genera of valid Appalachian tyrannosaurs are known,
Dryptosaurus,
Appalachiosaurus, and the recently discovered
Teihivenator while other indeterminate fossils lie scattered throughout most of the southern United States like Georgia, North Carolina, and South Carolina. Fossil foot bones from Appalachian deposits indicate another, unnamed tyrannosauroid measuring , indicating that diversity in these basal tyrannosauroids remained high during the Late Cretaceous. There is also the possibility of a fourth tyrannosaur known from Applachia known as
Diplotomodon, but the genus is considered dubious. Fossils from New Jersey and Delaware, most notably in the
Mt. Laurel Formation and
Merchantville Formations, have revealed that the primitive tyrannosauroids were much more diverse than expected, and some of them grew to lengths of 8 to 9 meters long, making them around the same size as some of the more advanced tyrannosaurs found in Laramidia. Fossils in Cenomanian deposits further indicate tyrannosauroids had been a constant presence in Appalachia since the Middle Cretaceous.
Dromaeosaurs The dryptosaurs were not the only predatory dinosaurs in Appalachia. Indeterminate
dromaeosaur fossils, possibly belonging to
Velociraptorinae and
Saurornitholestinae, and teeth, most closely matching those of
Saurornitholestes, have also been unearthed in Appalachia as well; mostly in the southern states like Missouri, North Carolina, South Carolina, Alabama, Mississippi and Georgia. Finds from the Campanian Tar Heel Formation in North Carolina indicate that there may have been dromaeosaurids of considerable size; intermediate between genera such as
Saurornitholestes and
Dakotaraptor. Though known only from teeth, the discovery indicates large dromaeosaurids were part of Appalachia's fauna. Along with the dromaeosaurid remains, tyrannosauroid and possible ornithomimid remains have been unearthed in Missouri as well. It should also be noted that dromaeosaur remains are more commonly found in the southern region of Appalachia when compared to the northern region, with their sizes ranging from smaller forms to gigantic forms. Recent fossils unearthed in New Jersey show that
maniraptorans were present in Appalachia as well.
Ornithomimids Various
ornithomimid bones, such as
Coelosaurus, have also been reported from Appalachia from Missouri, Mississippi, Alabama, Georgia and as far north in states like Maryland, New Jersey, and Delaware, but it is now believed that some of these are the bones of juvenile dryptosaurs while others belong to various undescribed species of ornithomimids. As of 2019, no distinct species of ornithomimosaurs have been identified yet, mostly due to the fact that no complete skeleton has been unearthed yet. However, it can be assumed that most of them were around the same size as their Laramidian relatives, though there is one specimen that could have reached a large size similar to
Gallimimus or
Beishanlong. In 2022, fossils from the
Eutaw Formation from Mississippi revealed that large ornithomimids did indeed roam Appalachia.
Other theropods Fossils from the Woodbine Formation in Texas, one of the few fossil sites that is one of Appalachia's more well preserved fossils, reveal that other theropods might have roamed Appalachia around the time when the Western Interior Seaway first formed, they include possible specimens of
allosauroids,
troodontids,
caenagnathids, dromaeosaurs, and tyrannosaurs.
Hadrosaurs Another common group, arguably the most widespread species in the area, of Appalachian dinosaurs were the hadrosaurs which were represented by three groups including
Hadrosauromorpha,
Hadrosauroidea, and the
Hadrosauridae which is now considered to be their "ancestral homeland"; eventually making their way to Laramidia,
Asia,
Europe,
South America and
Antarctica where they diversified into the
lambeosaurine and
saurolophine dinosaurs, though some of the primitive hadrosaurs were still present until the end of the Mesozoic. While the fossil record shows a staggering variety of hadrosaur forms in Laramidia, hadrosaur remains for Appalachia show less diversity due to the relative uncommon number of fossil beds. However, a decent number of hadrosaurs are known from Appalachia with
Protohadros,
Claosaurus, and
Lophorhothon representing
Hadrosauromorpha,
Hypsibema crassicauda and
Hypsibema missouriensis representing
Hadrosauroidea, and
Hadrosaurus and
Eotrachodon representing
Hadrosauridae. These hadrosaurs from Appalachia seem to be closely related to the crestless hadrosaurs of Laramidia like
Gryposaurus and
Edmontosaurus, despite the fact that they are not considered to be
saurolophines.
Claosaurus is known from a specimen which floated into the Interior Seaway and was found in Kansas, might also be from Appalachia, since it was found closer to the Appalachia side of the seaway and is unknown from Western North America. Hadrosaur remains have even been found in
Iowa, though in fragmentary remains,
Tennessee, most notably from the
Coon Creek Formation.
Hypsibema crassicauda, over fifty feet long, was one of the largest eastern hadrosaurs, outgrowing some of more derived western hadrosaurs like
Lambeosaurus and
Saurolophus. The genus likely took up the environmental niche occupied by large
sauropods in other areas, possibly grown to colossal sizes to that of
Magnapaulia and
Shantungosaurus.
Hypsibema missouriensis, was another large species of hadrosaur, but it grew up to 45 to 49 feet, which wasn't as large as
Hypsibema crassicauda. When it was first discovered in 1945, it was mistaken for a species of sauropod. Hypsibema missouriensis, possibly even all of the other hadrosaurs living on Appalachia, had serrated teeth for chewing the vegetation in the area. Hadrosaur fossils from the
Kanguk Formation in Axel Heiberg Island in Nunavut, Canada show that hadrosaurs were rather widespread throughout Appalachia. The fossils found in the Kanguk Formation also revealed the dietary preferences of hadrosaurs, which revealed that they had a diet of
conifers,
stems,
twigs, and various
deciduous plants. In 2020, the remains of one small-bodied hadrosaur and two small-bodied hadrosauromorphs were unearthed in the New Egypt Formation in New Jersey. The fossils were dated to the Maastrichtian, which was the last stage of the Cretaceous period that ended with the extinction the dinosaurs. This information would imply that Appalachia probably had a rich diversity of life, but research will be need in order to get a better picture of this lost world. In 2021, new remains of
Hypsibema missouriensis, also known as
Parrosaurus missouriensis, were unearthed in Missouri.
Lambeosaurs Indeterminate
lambeosaurinae remains, mostly similar to
Corythosaurus, have been reported from New Jersey's
Navesink Formation,
Bylot Island and
Nova Scotia, Canada. It cannot yet be explained how lambeosaurines might have reached Appalachia though some have theorized that a land bridge must have formed sometime during the
Campanian. In 2020, a forelimb belonging to a lambeosaur was unearthed in the
New Egypt Formation from New Jersey with evidence of sharks scavenging on its remains.
Ornithopods While ornithopod fossils have been unearthed in the eastern United States in the past, including footprints in Virginia, they primarily belonged to scrappy remains and couldn't be described as distinct species, with the exception being
Tenontosaurus. However, this all changed with the descriptions of
Convolosaurus and
Ampelognathus from early Cretaceous and late Cretaceous Texas, respectively.
Nodosaurs The
nodosaurids, a group of large, herbivorous
armored dinosaurs resembling
armadillos, are another testament to Appalachia's difference from Laramidia. During the early Cretaceous, the nodosaurids prospered and were one of the most widespread dinosaurs throughout North America. However, by the latest Cretaceous, nodosaurids were scarce in western North America, limited to forms like
Edmontonia,
Denversaurus and
Panoplosaurus; perhaps due to competition from the
ankylosauridae; though they did thrive in isolation, most notably in Appalachia, as mentioned earlier and in the case of
Struthiosaurus, Europe as well. Nodosaurid
scutes have been commonly found in eastern North America, while fossil specimens are very rare. Often the findings are not diagnostic enough to identify the species, but the remains attest to a greater number of these armored dinosaurs in Appalachia. Multiple specimens have been unearthed in
Kansas in the Niobrara Formation, Alabama in
Ripley Formation, Mississippi, Delaware, Maryland and New Jersey, possibly belonging to a multitude of different species. Five possible and best-known examples of Appalachian nodosaurids, from both the early and late Cretaceous period, include
Priconodon,
Propanoplosaurus,
Niobrarasaurus,
Silvisaurus and possibly
Hierosaurus, though its validity is disputed. Just like the
Claosaurus specimen, it is possible that the specimens of
Niobrarasaurus,
Silvisaurus and
Hierosaurus floated into the Interior Seaway from the east, since these two species of nodosaurids were discovered in the famous
chalk formations of Kansas and are not known from any location from Western North America. Kansas was also a part of Appalachia when the other parts were covered by oceans, which were a part of the Western Interior Seaway.
Ceratopsians While remains of the advanced ceratopsians, most notably the
centrosaurines and
chasmosaurines which were very common in Laramidia during this time period, they were long thought to be nonpresent in Appalachia, however this notion changed in 2016 when a ceratopsian tooth was unearthed in Mississippi's
Owl Creek Formation, which has been dated to be 67 million years old. The owner of this one particular tooth was probably a chasmosaurine since by the end of the Cretaceous while the centrosaurines had completely vanished from most of North America, though they were thriving in Asia as in the case of
Sinoceratops, and most likely entered Appalachia as soon as the Western Interior Seaway closed.
Leptoceratopsians Just like their larger cousins, the
leptoceratopsids were thought to be absent from Appalachia until the mid-2010s when a jaw bone of an indeterminate genus was unearthed in North Carolina. A
Campanian-era
leptoceratopsid ceratopsian has been found in the
Tar Heel Formation, marking the first discovery of a ceratopsian dinosaur in the Appalachian zone. This specimen bears a uniquely long, slender and downcurved upper jaw, suggesting that it was an animal with a specialized feeding strategy, yet another example of speciation on an island environment. While leptoceratopsid remains, the few that have been discovered in recent years have been unearthed in the southern part of Appalachia. They appear to be completely absent from the northern part of Appalachia, states like New Jersey, Delaware, and Maryland, suggesting the idea, proposed by paleontologist David R. Schwimmer, that there was a possible providence during the Late Cretaceous (although it may be a case of
preservation bias). It is not completely understood how the leptoceratopsians were able to reach Appalachia; however, the most commonly accepted theory was that they
island hopped from Europe during the time that the Western Interior Seaway split the North American continent into two different land masses in a way that some species of leptoceratopsids, most notably
Ajkaceratops, were able to reach Europe. It should also be noted that there is a distinct difference with how the leptoceratopsians evolved in Appalachia and Laramida. The Appalachian leptoceratopsian that was unearthed in the Tar Heel Formation, which grew to the size of a large dog, had a more slender jaw that teeth that curved downward and outward in its beak. This would imply a specialized feeding strategy for feeding on the foliage that was native to Appalachia during the
Campanian.
Birds Several bird remains are known from Appalachian sites, most of them
sea birds like
hesperornithes like
Hesperornis,
Canadaga,
Baptornis,
Fumicollis,
Parahesperornis, and
Ichthyornis,
enantiornithes like
Halimornis and
ornithurans like
Apatornis and
Iaceornis, possibly indicating that Appalachia may have possessed a diverse variety of birds that were endemic to the region. Of particular interest are possible
lithornithid remains in
New Jersey, arguably one of the best records for Cretaceous birds as some specimens were preserved in the
greensands in the area, which would represent a clear example of
palaeognath Neornithes in the Late Cretaceous. However, this issue is still under debate. Examples of birds that were endemic to Appalachia include a few groups such as the
charadriiformes, which consisted of
Graculavus and
Telmatornis,
anseriformes as represented by
Anatalavis,
procellariiformes with
Tytthostonyx being a representative of the group, and
Palaeotringa and
Laornis belonging to a currently unknown group of birds. Some birds found in Canada such as
Tingmiatornis and
Canadaga were found in areas that were a part of Appalachia.
Enantiornithine birds are also known from Appalachia, as is the case of
Flexomornis from the Woodbine Formation from Texas.
Non-dinosaur herpetofauna Amphibians Through the
Ellisdale Fossil Site, a good picture of Appalachia's amphibian fauna is present. Amidst
lissamphibians, there is evidence for
sirenids (including the large
Habrosaurus), the batrachosauroidid salamander
Parrisia,
hylids, and possible representatives of
Eopelobates and
Discoglossus. These show close similarities to European faunas, but aside from
Habrosaurus (which is also found on Laramidia) there is a high degree of endemism, suggesting no interchanges with other landmasses throughout the Late Cretaceous.
Lizards There is also a high degree of endemism in regards to its reptilian fauna: among squamates, the
teiid Prototeius is exclusive to the landmass, and native representatives of
iguanids,
helodermatids, and
necrosaurids are also known.
Snakes Fossilized remains of
snakes are rare in Appalachia and much more common in Laramidia most likely due to preservation bias. However, in the late 1980s, fossil remains of a Cretaceous era snake, attributed to
Coniophis, were unearthed in North Carolina.
Turtles Amidst
turtles, which are rather common finds in Appalachia,
Adocus,
Bothremys and
Chedighaii are well represented, the latter two in particular more common in Appalachian sites than Laramidian ones.
Pleurochayah, a
bothremyid, is known from Texas. In Santonian Alabama occurred the giant endemic
Appalachemys. Two marine
stem group-
trionychians,
"Trionyx" priscus and
"Trionyx" halophilus, are known from the eastern coastal margin of Appalachia (New Jersey, Delaware, Maryland and the Carolinas).
Crocodiles Crocodiles were rather abundant in Appalachia with nine local
crocodilian genera belonging to several confirmed families, with the possibility of much more undiscovered crocodiles waiting to be unearthed.
Goniopholididae is represented by
Dakotasuchus and
Woodbinesuchus,
Alligatoridae is represented by
Bottosaurus,
Neosuchia is represented by
Scolomastax and
Deltasuchus,
Alligatoroidea are presented
Deinosuchus and
Leidyosuchus,
Gavialoidea are represented by
Thoracosaurus,
Eothoracosaurus, and
Crocodilia is presented by
Borealosuchus, are well established in Laramidia as well, probably indicative of their ocean crossing capacities.
Deinosuchus, being one of the largest crocodilians of the fossil record, was an
apex predator that did prey on the dinosaurs in the area, the same case applies for Laramidia as well, despite the fact that the majority of its diet consisted of turtles and
sea turtles. However, crocodiles still preyed on the endemic dinosaurs whenever they got the chance to do so; there is evidence of crocodile bite marks on the femur of large ornithomimosaur that indicates the predatory behavior of native crocodiles. Fossils unearthed in South Carolina and New Jersey shows that some of the crocodilians endemic to Appalachia survived the extinction of the dinosaurs and even persisted into the Cenozoic.
Dyrosauridae Dyrosauridae, most notably
Dyrosaurus and
Hyposaurus fossils, are also known form Appalachia, particularly in New Jersey, Alabama, and South Carolina.
Pholidosauridae Only one species of
pholidosaurid is known to have lived in Appalachia;
Terminonaris whose remains have been unearthed in Texas. Kansas, and Minnesota.
Pterosaurs Pterosaur fossils, mostly similar to
Pteranodon and
Nyctosaurus, have been unearthed in Georgia, Alabama and Delaware. On a similar note,
azhdarchid remains, which belong to
Arambourgiania, have been unearthed in Tennessee. Azhdarchid remains have also been unearthed in North Carolina. There have been a number of specimens of pterosaurs unearthed in areas that were a part of Appalachia during the time that the Western Interior Seaway had divided North America into two landmasses. Fossils of Appalachian pterosaurs have also been unearthed in
Kansas and
Texas.
Pteranodontidae seems to be the most common group of pterosaurs in Appalachia and is represented by five species:
Pteranodon,
Nyctosaurus,
Geosternbergia,
Dawndraco, and
Alamodactylus. Members of the
Ornithocheiridae and
Anhangueridae are represented by
Aetodactylus and
Cimoliopterus respectively.
Choristodera The remains of indeterminate
choristoderans have turned up in the
Navesink Formation; the only known genus of choristodere during the Late Cretaceous was
Champsosaurus. As a whole Appalachian choristodere fossils are very rare, speculated to the result of the lack of a suitable cold freshwater environment as seen in Laramidia at similar latitudes; the animals are speculated to have been more common at higher latitudes and altitudes. are also present in
Ellisdale and in both of
the Carolinas. The most common are
ptilodontoidean
multituberculates, such as
Mesodma,
Cimolodon and a massively-sized species. The sheer diversity of species on the landmass, as well as the earlier appearance compared to other Late Cretaceous locales, suggests that ptilodontoideans evolved in Appalachia.
Metatherians are also known, including an
alphadontid, and a
herpetotheriid. Unlike ptilodontoideans, metatherians show a lesser degree of endemism, implying a degree of interchange with Laramidia and Europe. Research in this area has revealed that the
Taeniolabidoidea mammals can trace their origins here and that there were several species of multituberculates endemic to Appalachia.
Eutheria fossils, most notably molars, have also been unearthed in Mississippi. It is possible that they belong to a creature rather reminiscent to
Protungulatum. The genus
Alphadon as well as members of the
Allotheria family have had their remains unearthed in New Jersey.
Marine life While not much was known about Appalachia's land-based fauna until recently, the marine life that in the area, as well as the life that lived in the nearby Western Interior Seaway, has been well studied by paleontologists for years. Such examples of fossil sites that have preserved the remains of marine life from that period include the Niobrara Formation, the Demopolis Chalk Formation, and the Mooreville Chalk Formation are just a few examples of the fossil sites that have successfully preserved the skeletal remains of various marine creatures from the Cretaceous. Examples of the marine fauna that lived near Appalachia include
chondrichthyes,
osteichthyes,
chelonioids,
plesiosaurs, and
mosasaurs, which were the apex predators of their environment at the time. Plesiosaur fossils, belonging to the genus
Cimoliasaurus, have been unearthed in New Jersey. Mosasaur remains have also been unearthed in Missouri. Fish fossils are rather common throughout Appalachia, especially in locations abundant in
marl,
shale, and
limestone. Fish fossils, as well as a lot of Cretaceous era marine fauna, are rather abundant in regions like the Niobrara Formation in Kansas, which is made up of shale, sandstone and limestone, as well as the
Woodbury Formation in New Jersey.
Arthropods Many species of arthropods are known from the Turonian aged
New Jersey amber, situated on the Atlantic coast of Appalachia. Arthropods are also known from the Cenomanian aged
Redmond Formation of Labrador, Canada. ==Flora==