Wannagan Creek site
Encyclopedia
The Wannagan Creek site is a fossil
site found just west of the South Unit of Theodore Roosevelt National Park
of North Dakota
, USA
. The site is Paleocene
in age, approximately 60 million years old. Paleontologists
of the Science Museum of Minnesota
have studied the site for nearly thirty years. The site is thought to represent a paleoenviroment of subtropical swampy lowland and forests. Preservation is excellent for both the flora and fauna of the site. Trace fossils of crocodilia
ns and other vertebrate
s have also been discovered.
of the Little Missouri River
. The rock units are likely sediments derived from the Laramide orogeny
deposited in an ecosystem
dominated by river
s, stream
s, pond
s, lake
s, and swamp
s.
The Wannagan Site is found in the upper portion of the Tongue River Formation (formerly Bullion Creek Formation). The rocks of this deposit consist of yellow to tan, poorly lithified claystone
s, mudstone
s, and siltstone
s with a lesser amounts of interbedded fine-grained sandstone
s and lignite
and at the Wannagan Site reach a thickness of over 60 m. The Wannagan Creek site is overlain by the Sentinel Butte Formation. This formation is generally gray to brown in color but is similar in lithology
to the Tongue River. The Sentinel Butte is roughly 90 m thick. The contact between the two formations is roughly 6 m above the Wannagan site. The Sentinel Butte contains an extensive stump-bearing petrified wood
bed above the contact at the site.
s are found at the site. All are small compared to modern mammals, the largest being sheep-sized. Preserved mammals include a squirrel
-like primitive primate
and Ptilodus
; an arboreal multituberculate. The largest mammal at the site is the condylarth
herbivore Phenacodus
. An additional mammal fossil is Protictis, a weasel sized member of Viverridae that may have hunted on the forest floor.
Reptile
s are the dominant animal type preserved at Wannagan. The largest animal (~4 meters [13 ft] in length) found at the site is the eusuchia
n crocodilia
n Borealosuchus
formidabilis (formerly known as Leidyosuchus
formidabilis). B. formidabilis is also thought to be the apex predator
of the fauna. The second largest reptile is the champsosaur Champsosaurus
gigas. C. gigas is unusual among Paleocene reptiles in that it is larger than its known Mesozoic
ancestors; 3 meters (10 ft) in length versus 1.5 meters (4.5 ft) for the largest Cretaceous
champsosaurs. Reptiles as a whole decreased in size after the Cretaceous–Tertiary extinction event. Other reptiles include soft-shelled turtle
s, varanid lizard
s, a small alligatorid
called Wannaganosuchus
, palaeophid snakes, and the snapping turtle
-like Protochelydra
zangerli.
Bird
s from Wannagan include an ibis
, an unnamed water bird, and a plover
-like shore bird. The two types amphibian
s found at Wannagan are the giant salamander
Piceorpeton willwoodense and frog
s. Fish
include fossil Esox
, freshwater rays
, gar
, and bowfin
. Additionally, the dragonfly
Gomphaeschna schrankii and the mayfly
Ephemeropteran have been found.
s at Wannagan Creek include palm
s, ginkgo
trees, bald cypress, dogwood
s, oak
s, elms, fig trees
, magnolias, dawn redwoods, hackberries
, sassafras
, sycamores
, cherries, mulberries. and cycad
s. Additional plants found at the site are grape
vines, lotus
, bur-reeds, cattails, and water-plantago
.
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
site found just west of the South Unit of Theodore Roosevelt National Park
Theodore Roosevelt National Park
Theodore Roosevelt National Park is a United States National Park comprising three geographically separated areas of badlands in western North Dakota. The park was named for U.S. President Theodore Roosevelt, in honor of his achievements in conservation as president and for the landscape's...
of North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
, USA
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The site is Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
in age, approximately 60 million years old. Paleontologists
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
of the Science Museum of Minnesota
Science Museum of Minnesota
The Science Museum of Minnesota is an American museum focused on topics in technology, natural history, physical science and mathematics education. Founded in 1907 and located in Saint Paul, Minnesota, the 501 nonprofit institution is staffed by over 500 employees and over 1,600 volunteers...
have studied the site for nearly thirty years. The site is thought to represent a paleoenviroment of subtropical swampy lowland and forests. Preservation is excellent for both the flora and fauna of the site. Trace fossils of crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
ns and other vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s have also been discovered.
Topography/Geology
The topography of the site is that of a badland, due to the downcuttingDowncutting
Downcutting, also called erosional downcutting or downward erosion or vertical erosion is a geological process that deepens the channel of a stream or valley by removing material from the stream's bed or the valley's floor. How fast downcutting occurs depends on the stream's base level, which is...
of the Little Missouri River
Little Missouri River (North Dakota)
The Little Missouri River is a tributary of the Missouri River, 560 mi long, in the northern Great Plains of the United States. Rising in northeastern Wyoming, in western Crook County about west of Devil's Tower, it flows northeastward, across a corner of southeastern Montana, and into South Dakota...
. The rock units are likely sediments derived from the Laramide orogeny
Laramide orogeny
The Laramide orogeny was a period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute, as is the cause. The Laramide...
deposited in an ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
dominated by river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s, stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...
s, pond
Pond
A pond is a body of standing water, either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens, water features and koi ponds; all designed for aesthetic ornamentation as landscape or architectural...
s, lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s, and swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s.
The Wannagan Site is found in the upper portion of the Tongue River Formation (formerly Bullion Creek Formation). The rocks of this deposit consist of yellow to tan, poorly lithified claystone
Claystone
Claystone is a geological term used to describe a clastic sedimentary rock that is composed primarily of clay-sized particles ....
s, mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
s, and siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
s with a lesser amounts of interbedded fine-grained sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
s and lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
and at the Wannagan Site reach a thickness of over 60 m. The Wannagan Creek site is overlain by the Sentinel Butte Formation. This formation is generally gray to brown in color but is similar in lithology
Lithology
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples or with low magnification microscopy, such as colour, texture, grain size, or composition. It may be either a detailed description of these characteristics or be a summary of...
to the Tongue River. The Sentinel Butte is roughly 90 m thick. The contact between the two formations is roughly 6 m above the Wannagan site. The Sentinel Butte contains an extensive stump-bearing petrified wood
Petrified wood
Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of permineralization...
bed above the contact at the site.
Fauna
Many mammalMammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s are found at the site. All are small compared to modern mammals, the largest being sheep-sized. Preserved mammals include a squirrel
Squirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
-like primitive primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
and Ptilodus
Ptilodus
Ptilodus is a genus of mammals from the extinct order of Multituberculata, and lived during the Paleocene in North America.Ptilodus was a relatively large multituberculate of in length, which is about the same size as a squirrel...
; an arboreal multituberculate. The largest mammal at the site is the condylarth
Condylarth
Condylarthra is an order of extinct placental mammals known primarily from the Paleocene and Eocene epochs. Condylarths are among the most characteristic Paleocene mammals and they illustrate the evolutionary level of the Paleocene mammal fauna....
herbivore Phenacodus
Phenacodus
Phenacodus is an extinct genus of mammals from the late Paleocene through middle Eocene, about 55 million years ago. It is one of the earliest and most primitive of the ungulate mammals, typifying the family Phenacodontidae and the order Condylarthra....
. An additional mammal fossil is Protictis, a weasel sized member of Viverridae that may have hunted on the forest floor.
Reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s are the dominant animal type preserved at Wannagan. The largest animal (~4 meters [13 ft] in length) found at the site is the eusuchia
Eusuchia
Eusuchia is a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. All living crocodilian species are eusuchians, as are many extinct forms.-Description:...
n crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
n Borealosuchus
Borealosuchus
Borealosuchus is an extinct genus of crocodilian that lived from the Late Cretaceous to the Eocene in North America. It was named by Chris Brochu in 1997 for several species that had been assigned to Leidyosuchus. The species assigned to it are:B...
formidabilis (formerly known as Leidyosuchus
Leidyosuchus
Leidyosuchus is an extinct genus of alligatoroid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is L. canadensis. It is known from a number of specimens from the middle Campanian age Dinosaur Park Formation...
formidabilis). B. formidabilis is also thought to be the apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
of the fauna. The second largest reptile is the champsosaur Champsosaurus
Champsosaurus
Champsosaurus is an extinct genus of diapsid reptile belonging to the order Choristodera. It grew to about 1.50 m long....
gigas. C. gigas is unusual among Paleocene reptiles in that it is larger than its known Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
ancestors; 3 meters (10 ft) in length versus 1.5 meters (4.5 ft) for the largest Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
champsosaurs. Reptiles as a whole decreased in size after the Cretaceous–Tertiary extinction event. Other reptiles include soft-shelled turtle
Turtle
Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
s, varanid lizard
Monitor lizard
Monitor lizards are usually large reptiles, although some can be as small as in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semiaquatic monitors are also known...
s, a small alligatorid
Alligatoridae
Alligatoridae is a family of crocodylians that includes alligators and caimans.- True alligators :Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A...
called Wannaganosuchus
Wannaganosuchus
Wannaganosuchus is an extinct genus of small alligatorid...
, palaeophid snakes, and the snapping turtle
Chelydridae
Chelydridae is a family of turtles which has seven extinct and two extant genera. The extant genera are Chelydra the snapping turtles, and its larger relative Macrochelys, of which the Alligator Snapping Turtle is the only species. Both are endemic to the Western Hemisphere...
-like Protochelydra
Protochelydra
Protochelydra is an extinct genus of Chelydridae....
zangerli.
Bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s from Wannagan include an ibis
Ibis
The ibises are a group of long-legged wading birds in the family Threskiornithidae....
, an unnamed water bird, and a plover
Plover
Plovers are a widely distributed group of wading birds belonging to the subfamily Charadriinae. There are about 40 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subfamily, Vanellinae, comprises another 20-odd species.Plovers are found throughout...
-like shore bird. The two types amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s found at Wannagan are the giant salamander
Giant salamander
The hellbender and Asian giant salamanders are aquatic amphibians found in brooks and ponds in the United States, China, and Japan. They are the largest living amphibians known today...
Piceorpeton willwoodense and frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s. Fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
include fossil Esox
Esox
Esox is a genus of freshwater fish, the only living genus in the family Esocidae — the esocids which were endemic to North America, Europe and Eurasia during the Paleogene through present.The type species is E. lucius, the northern pike...
, freshwater rays
Batoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
, gar
Gar
In American English the name gar is strictly applied to members of the Lepisosteidae, a family including seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine, waters of eastern North America, Central America, and the Caribbean islands.-Etymology:In...
, and bowfin
Bowfin
The Bowfin, Amia calva, is the last surviving member of the order Amiiformes , and of the family Amiidae...
. Additionally, the dragonfly
Dragonfly
A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...
Gomphaeschna schrankii and the mayfly
Mayfly
Mayflies are insects which belong to the Order Ephemeroptera . They have been placed into an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies...
Ephemeropteran have been found.
Flora
The flora of Wannagan is quite well preserved in some cases, with evidence of insect feeding found on many fossils. Most of the fossils have modern equivalents. The list of treeTree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s at Wannagan Creek include palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
s, ginkgo
Ginkgo
Ginkgo , also spelled gingko and known as the Maidenhair Tree, is a unique species of tree with no close living relatives...
trees, bald cypress, dogwood
Dogwood
The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
s, oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
s, elms, fig trees
Ficus
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...
, magnolias, dawn redwoods, hackberries
Hackberries
Hackberries is a common name for* the deciduous trees in the genus Celtis* some of the butterflies in the genus Asterocampa...
, sassafras
Sassafras
Sassafras is a genus of three extant and one extinct species of deciduous trees in the family Lauraceae, native to eastern North America and eastern Asia.-Overview:...
, sycamores
Platanus
Platanus is a small genus of trees native to the Northern Hemisphere. They are the sole living members of the family Platanaceae....
, cherries, mulberries. and cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s. Additional plants found at the site are grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
vines, lotus
Nelumbo
Nelumbo is a genus of aquatic plants with large, showy flowers resembling water lilies, commonly known as lotus. The generic name is derived from the Sinhalese word Nelum. There are only two known living species in the genus. The sacred lotus is native to Asia, and is the better known of the two...
, bur-reeds, cattails, and water-plantago
Plantago
Plantago is a genus of about 200 species of small, inconspicuous plants commonly called plantains. They share this name with the very dissimilar plantain, a kind of banana. Most are herbaceous plants, though a few are subshrubs growing to 60 cm tall. The leaves are sessile, but have a narrow...
.
External links
- North Dakota Geological Survey Paleontology of Theodore Roosevelt National Park
- Science Museum of Minnesota Science Museum of Minnesota's Wannagan website
- The National Park Service Theodore Roosevelt National Park's Paleontology
- Paleobiology Database: Wannagan Creek Quarry: Tiffanian, North Dakota
- Paleobiology Database: One Mile North of Wannagan Creek Quarry: Late/Upper Paleocene, North Dakota