Ptilodus
Encyclopedia
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 30 to 50 cm (11.8 to 19.7 in) in length, which is about the same size as a squirrel
. Its feet, legs and long tail suggest it was a good climber, so it very possibly lead a squirrel-like lifestyle.
The genus was named by paleontologist Edward Drinker Cope
in 1881. Cope also mistakenly assigned some material belonging to this genus to Chirox in 1884. Elements from Ectypodus (Jepsen, 1940) and Neoplagiaulax
have also been reassigned to this genus.
, and others have been proposed at one time or another. P. nellieae (Bell, 1941) is apparently mentioned in a manuscript, rather than a publication. P. sinclairi (Simpson
, 1935) seems to have become Parectypodus
sinclairi. In botany
, Ptilodus pyramidatus is an extinct Australia
n plant.
, in the United States
, in Dell Creek deposits dated to the Tiffanian stage
of the Paleocene.
The species was named by J. A. Door in 1952 (Scott et al., 2002, Dorr, 1952), though it may have been amended to its current state by David Krause in 1987.
for 'dwarf'. Remains have been discovered in Wyoming in the United States, and Alberta
, Canada
. They were recovered from the Cochrane 2 deposits of the Paskapoo Formation, which have been dated to the Tiffanian stage of the Paleocene.
Remains of this species include over 100 teeth, (upper and lower), and at least one fragment of jaw. The teeth range from 2 to 5 mm (0.078740157480315 to 0.196850393700787 in) in length. The fourth lower premolar
(p4) is about 51% shorter than the corresponding tooth in P. mediaevus; 28% less than P. kummae; 15% less than P. tsosiensis; and 5% smaller than P. fractus, which gives some idea of the relative sizes of the various animals. There are also differences in shape and the number of serrations. (Scott et al., 2002)
A couple of isolated teeth which had been previously identified as perhaps belonging to Ectypodus, have been now been placed within this taxon. All referred specimens are held in the collection of the University of Alberta
.
The species was named by C. R. Scott, R. C. Fox, and G. P. Youzwyshyn in 2002. Material assigned by Jepsen in 1940, as amended by Gazin in 1956, to Ectypodus hazeni has also been assigned to this species.
There are three species of this genus
known from the Alberta location, two of which have yet to be described. This will be attended to by David W. Krause. (Scott et al., 2002, pg. 691).
in Canada, in deposits from the lower Tiffanian stage of the Paleocene.
The species was named by David W. Krause in 1977. (Krause, 1977) The holotype
is at Alberta University.
, Utah
, and Wyoming in the United States. They have been unearthed from the deposits of the San Juan Basin, which are dated to the Torrejonian stage of the Paleocene.
Cope named the species in 1881 (Cope, 1881). The species Ptilodus feronensis, or Ptilodus ferronensis, was named C. L. Gazin in 1941 (Gazin, 1941), but all material was reassigned to P. mediaevus by Rigby in 1980. In 1929, Granger and Simpson did the same thing to the species P. plicatus, which was originally named by J. W. Gidley in 1909. Chirox plicatus was named by Cope in 1884. He described it as a marsupial
in 1884, but it is also part of this species.
The species was named by E. Douglass in 1908 (Douglass, 1908). The species P. admiralis, first described by Hay in 1930; and P. gracillis, first described by J. W. Gidley in 1909 (Gidley, 1909) are now considered part of this species.
in the United States. The species was named by G. L. Jepsen in 1940 (Jepsen, 1940).
Multituberculata
The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...
, and lived during the 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 North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
Ptilodus was a relatively large multituberculate of 30 to 50 cm (11.8 to 19.7 in) in length, which is about the same size as 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...
. Its feet, legs and long tail suggest it was a good climber, so it very possibly lead a squirrel-like lifestyle.
The genus was named by paleontologist Edward Drinker Cope
Edward Drinker Cope
Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
in 1881. Cope also mistakenly assigned some material belonging to this genus to Chirox in 1884. Elements from Ectypodus (Jepsen, 1940) and Neoplagiaulax
Neoplagiaulax
Neoplagiaulax is a mammal genus from the Paleocene of Europe and North America. In the case of the latter continent, there may possibly be some slightly earlier, Upper Cretaceous material too. It existed in the age immediately following the extinction of the last dinosaurs...
have also been reassigned to this genus.
Species
There are seven speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, and others have been proposed at one time or another. P. nellieae (Bell, 1941) is apparently mentioned in a manuscript, rather than a publication. P. sinclairi (Simpson
George Gaylord Simpson
George Gaylord Simpson was an American paleontologist. Simpson was perhaps the most influential paleontologist of the twentieth century, and a major participant in the modern evolutionary synthesis, contributing Tempo and mode in evolution , The meaning of evolution and The major features of...
, 1935) seems to have become Parectypodus
Parectypodus
Parectypodus is a genus of extinct mammal that lived from the Paleocene to the Eocene of North America. Some of the known fossil material may also be from the Upper Cretaceous. It was named by G.L. Jepsen in 1930....
sinclairi. In botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, Ptilodus pyramidatus is an extinct Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n plant.
P. fractus
The species Ptilodus fractus had a body weight of about 95 grams (3.4 oz). Remains have been found in WyomingWyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, in Dell Creek deposits dated to the Tiffanian stage
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of the Paleocene.
The species was named by J. A. Door in 1952 (Scott et al., 2002, Dorr, 1952), though it may have been amended to its current state by David Krause in 1987.
P. gnomus
Ptilodus gnomus is the smallest known member of the genus. Hence, the species epithet 'gnomus', which is New LatinNew Latin
The term New Latin, or Neo-Latin, is used to describe the Latin language used in original works created between c. 1500 and c. 1900. Among other uses, Latin during this period was employed in scholarly and scientific publications...
for 'dwarf'. Remains have been discovered in Wyoming in the United States, and Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. They were recovered from the Cochrane 2 deposits of the Paskapoo Formation, which have been dated to the Tiffanian stage of the Paleocene.
Remains of this species include over 100 teeth, (upper and lower), and at least one fragment of jaw. The teeth range from 2 to 5 mm (0.078740157480315 to 0.196850393700787 in) in length. The fourth lower premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
(p4) is about 51% shorter than the corresponding tooth in P. mediaevus; 28% less than P. kummae; 15% less than P. tsosiensis; and 5% smaller than P. fractus, which gives some idea of the relative sizes of the various animals. There are also differences in shape and the number of serrations. (Scott et al., 2002)
- Although more similar in size to homologous teeth referable to P. tsosiensis and P. fractus, the upper and lower ultimate premolars of this new species most closely resemble those of P. mediaevus in overall morphology. (Scott et al., 2002)
A couple of isolated teeth which had been previously identified as perhaps belonging to Ectypodus, have been now been placed within this taxon. All referred specimens are held in the collection of the University of Alberta
University of Alberta
The University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
.
The species was named by C. R. Scott, R. C. Fox, and G. P. Youzwyshyn in 2002. Material assigned by Jepsen in 1940, as amended by Gazin in 1956, to Ectypodus hazeni has also been assigned to this species.
There are three species of this genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
known from the Alberta location, two of which have yet to be described. This will be attended to by David W. Krause. (Scott et al., 2002, pg. 691).
P. kummae
Ptilodus kummae has an estimated weight of 120 grams (4.2 oz). Remains have been discovered in Roche Percée, SaskatchewanSaskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
in Canada, in deposits from the lower Tiffanian stage of the Paleocene.
The species was named by David W. Krause in 1977. (Krause, 1977) The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
is at Alberta University.
P. mediaevus
Remains of Ptilodus mediaevus have been recovered in New MexicoNew Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, and Wyoming in the United States. They have been unearthed from the deposits of the San Juan Basin, which are dated to the Torrejonian stage of the Paleocene.
Cope named the species in 1881 (Cope, 1881). The species Ptilodus feronensis, or Ptilodus ferronensis, was named C. L. Gazin in 1941 (Gazin, 1941), but all material was reassigned to P. mediaevus by Rigby in 1980. In 1929, Granger and Simpson did the same thing to the species P. plicatus, which was originally named by J. W. Gidley in 1909. Chirox plicatus was named by Cope in 1884. He described it as a marsupial
Marsupial
Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
in 1884, but it is also part of this species.
P. montanus
Ptilodus montanus is a large species, about 650 grams (22.9 oz)]. A brain cast indicates a well-developed sense of smell. Remains were recovered in Montana, in the rock of the Silberling Quarry, which is dated to the lower Tiffanian stage of the Paleocene.The species was named by E. Douglass in 1908 (Douglass, 1908). The species P. admiralis, first described by Hay in 1930; and P. gracillis, first described by J. W. Gidley in 1909 (Gidley, 1909) are now considered part of this species.
P. tsosiensis
Ptilodus tsosiensis has been discovered in New Mexico, the Puercan stage deposits of the Lower Paleocene San Juan Basin. The species was named by R. E. Sloan in 1981 (Sloan, 1981).P. wyomingensis
Remains of Ptilodus wyomingensis have been found in the Middle Paleocene deposits of the Rock Bench Quarry, in Wyoming and North DakotaNorth 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....
in the United States. The species was named by G. L. Jepsen in 1940 (Jepsen, 1940).