''Podokesaurus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

coelophysoid Coelophysoidea were common dinosaurs of the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to th ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

that lived in what is now the eastern United States during the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...

Period. The first fossil was discovered by the geologist

Mignon Talbot Mignon Talbot (August 16, 1869 – July 18, 1950) was an American paleontologist. Talbot recovered and named the only known fossils of the dinosaur '' Podokesaurus holyokensis'', which were found near Mount Holyoke College in 1910, and published ...

near

Mount Holyoke Mount Holyoke, a traprock mountain, elevation , is the westernmost peak of the Holyoke Range and part of the 100-mile (160 km) Metacomet Ridge. The mountain is located in the Connecticut River Valley of western Massachusetts, and is the ...

Massachusetts Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...

, in 1910. The specimen was fragmentary, preserving much of the body, limbs, and tail. In 1911, Talbot described and named the new genus and species ''Podokesaurus holyokensis'' based on it. The full name can be translated as "swift-footed lizard of Holyoke". This discovery made Talbot the first woman to find and describe a non-bird dinosaur. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

fossil was recognized as significant and was studied by other researchers, but was lost when the building it was kept in burned down in 1917; no unequivocal ''Podokesaurus'' specimens have since been discovered. It was made

state dinosaur State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * '' Our ...

of Massachusetts in 2022. Estimated to have been about in length and in weight, ''Podokesaurus'' was lightly constructed with hollow bones, and would have been similar to ''

Coelophysis ''Coelophysis'' ( traditionally; or , as heard more commonly in recent decades) is an extinct genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago during the latter part of the Triassic Period fro ...

'', being slender, long-necked, and with sharp, recurved teeth. The were very light and hollow, and some were slightly concave at each end. The (neck) vertebrae were relatively large in length and diameter compared to the (back) vertebrae, and the (tail) vertebrae were long and slender. The (upper-arm bone) was small and delicate, less than half the length of the (thigh-bone). The pubis (pubic bone) was very long, expanding both at the front and hind ends. The femur was slender, nearly straight, had thin walls, and was expanded at the back side of its lower end. The three of the lower leg were closely appressed together forming a compact structure. Since it was one of the few small

theropods Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally ca ...

known at the time it was described, the

affinities In post-classical history, an affinity was a collective name for the group (retinue) of (usually) men whom a lord gathered around himself in his service; it has been described by one modern historian as "the servants, retainers, and other fol ...

of ''Podokesaurus'' were long unclear. It was placed in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Podokesauridae along with other small theropods, and was speculated to have been similar to a

proto-bird Proavis refers to a hypothetical extinct species or hypothetical extinct taxon and was coined in the early 20th century in an attempt to support and explain the hypothetical evolutionary steps and anatomical adaptations leading from non-avian th ...

. It was suggested it was a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

of ''Coelophysis'' and a natural cast specimen was assigned to it, but these ideas are not currently accepted. The family Podokesauridae is not in use anymore, having been replaced by Coelophysidae, and ''Podokesaurus'' is thought to have been a coelophysoid. As such, ''Podokesaurus'' would have been a fleet-footed predator, with powerful forelimbs and grasping hands. It is estimated it could have run at . ''Podokesaurus'' is thought to have been collected from the

Portland Formation The Portland Formation is a geological formation in Connecticut and Massachusetts in the northeastern United States.date to the

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triassi ...

–

Sinemurian In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.3 ± 2 Ma and 190.8 ± 1.5 Ma (million years ago). The Sinemurian is preceded by the Hettangian and ...

stages of the Early Jurassic, between 201 and 190 million years ago.

Discovery and history

In 1910, the American geologist

was walking with her sister Ellen to

Holyoke Holyoke is a city in Hampden County, Massachusetts, United States, that lies between the western bank of the Connecticut River and the Mount Tom Range. As of the 2020 census, the city had a population of 38,238. Located north of Springfiel ...

, in the eastern US, when they passed a farm and noticed a small hill nearby. It had a gravel pit at one side, and was formed by an accumulation of sand, gravel, and boulders left by a receding

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...

. Talbot noticed a white streak on a

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

boulder at the bottom of the gravel pit, and upon discovering these were bones, she told her sister she had found a "real live fossil". This was because many

fossil tracks A fossil track or ichnite ( Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the y ...

had previously been discovered in the

Connecticut Valley The Connecticut River is the longest river in the New England region of the United States, flowing roughly southward for through four states. It rises 300 yards (270 m) south of the U.S. border with Quebec, Canada, and discharges at Long Isl ...

(that she had often taken her students to see), but few actual

skeletons, and none at

. She was granted permission by the land owner to collect the specimen for

Mount Holyoke College Mount Holyoke College is a private liberal arts women's college in South Hadley, Massachusetts. It is the oldest member of the historic Seven Sisters colleges, a group of elite historically women's colleges in the Northeastern United States. ...

(an all-women's college a few miles from there), where she was head of the geology department. The next day she brought a group of workmen to collect the specimen, and found another piece of sandstone that contained the rest of the fossil as well as impressions of those in the first slab. The specimen appeared to have been exposed for years with no one noticing it, the boulder having been broken open by people or frost. The fossil was brought to the laboratory where it was prepared and photographed. The incomplete specimen preserved 5 (neck), 11 (back) and 24 (tail) vertebrae, a fragment of the left (shoulder blade) and right (part of the ), a partial left (upper arm bone), of 3 fingers, including 2 (claw bones), ribs, the and (bones forming the lower front and lower back of the pelvis, respectively), the (thigh bones), the left (lower leg bone), a fragment of the right (a bone in the ankle), articulated (foot bones) of the left foot, followed by 3 pedal phalanges (toe bones), partial metatarsals and possible phalanges of the right foot, and fragments of uncertain identity. The light and delicate bones were in their natural position or nearly so within the rock, except for the tail and uncertain fragments, which were a few centimeters away from the skeleton, following a long gap in the skeleton behind the pelvis. The front half of the neck was missing. The significance of the fossil was confirmed at an intercollegiate meeting of geology departments, and when the American paleontologist

Richard Swann Lull Richard Swann Lull (November 6, 1867 – April 22, 1957) was an American paleontologist and Sterling Professor at Yale University who is largely remembered now for championing a non-Darwinian view of evolution, whereby mutation(s) could ...

subsequently encouraged Talbot to describe the specimen, she replied she did not know anything about dinosaurs, but Lull suggested she should study them and then describe it. In December 1910, Talbot read a preliminary description of the fossil at the

Paleontological Society The Paleontological Society, formerly the Paleontological Society of America, is an international organisation devoted to the promotion of paleontology. The Society was founded in 1908 in Baltimore, Maryland, and was incorporated in April 1968 in ...

meeting at

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...

, and in June 1911 she published a short

scientific description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have b ...

, in which she made the specimen the

of the new

and

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

''Podokesaurus holyokensis''. The generic name is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

words ''podōkēs'' (), which means "swift (or fleet)-footed", an

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

commonly used in reference to the Greek hero

Achilles In Greek mythology, Achilles ( ) or Achilleus ( grc-gre, Ἀχιλλεύς) was a hero of the Trojan War, the greatest of all the Greek warriors, and the central character of Homer's '' Iliad''. He was the son of the Nereid Thetis and Pe ...

, and ''saura'' () meaning "lizard", while the specific name refers to Holyoke. In full, the name can be translated as "swift-footed lizard of Holyoke". The discovery and naming of ''Podokesaurus'' made Talbot the first woman to find and describe a non-bird dinosaur. The American paleontologist Robert T. Bakker stated in 2014 that while old professors grumbled that women were unfit for working with fossils during his time at university, Talbot's discovery of ''Podokesaurus'' was a counterargument to that. By the time the description was published, Talbot had sent the fossil to the

Peabody Museum of Natural History The Peabody Museum of Natural History at Yale University is among the oldest, largest, and most prolific university natural history museums in the world. It was founded by the philanthropist George Peabody in 1866 at the behest of his nephew Oth ...

Yale University Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the w ...

for further preparation and study, where cast replicas were also made of the bones as they lay in the rock. There, Lull drew a reconstruction of the skeleton, basing the parts missing from the fossil on the equivalents in ''

Compsognathus ''Compsognathus'' (; Ancient Greek, Greek ''kompsos''/κομψός; "elegant", "refined" or "dainty", and ''gnathos''/γνάθος; "jaw") is a genus of small, bipedalism, bipedal, carnivore, carnivorous theropoda, theropod dinosaur. Members o ...

'', and created a model of the animal in life, which Talbot later described as having a "sardonic smile". Lull expanded on Talbot's article in a 1915 publication, wherein he also proposed other identities for some of the bones than what she had originally suggested, including a partial coracoid instead of a scapula and part of the tibia instead of the (part of the hips). Lull suggested that the boulder containing the fossil must have come from a ledge which lay on the south side of the

Holyoke Range The Holyoke Range or Mount Holyoke Range is a traprock mountain range located in the Connecticut River Valley of Massachusetts. It is a sub-range of the narrow, linear Metacomet Ridge that extends from Long Island Sound near New Haven, Connec ...

, about two or three miles north of where it was found, and specified that it was from the Longmeadow Sandstone. Williston Hall debris

Lull had sent his manuscript to the Danish ornithologist

Gerhard Heilmann Gerhard Heilmann (later sometimes spelt "Heilman") (25 June 1859 – 26 March 1946) was a Danish artist and paleontologist who created artistic depictions of ''Archaeopteryx'', '' Proavis'' and other early bird relatives apart from writing the 19 ...

for criticism prior to publication. Heilmann published his response in a 1913 article in which he included previously unpublished photos of the fossil received from Talbot, as well as his own restorations. He disagreed with some of Lull's anatomical interpretations, and had corresponded regarding the fossil with the American zoologist Robert Wilson Shufeldt about his contentions. Heilmann's article was one in a series about the

origin of birds The scientific question of within which larger group of animals birds evolved has traditionally been called the "origin of birds". The present scientific consensus is that birds are a group of maniraptoran theropod dinosaurs that originated ...

, wherein he examined the skeletons of prehistoric reptiles to find traits that may have been ancestral to birds. In a 1916

Washington Academy of Sciences Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

meeting, Shufeldt gave an account of his correspondence with Lull, Talbot, and Heilmann, and agreed with the latter in some of his criticisms of Lull's restoration of ''Podokesaurus''. Talbot wanted the fossil to stay at Yale or

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

on permanent exhibit, where it could "be with its kind", but it was kept at Mount Holyoke in the old science building, Williston Hall, as a local specimen, where it became a "pet curiosity" for the students. During the Christmas break of 1917, Williston Hall burned down, and no remains of the ''Podokesaurus'' fossil were found in the rubble. The American writer Christopher Benfey pointed out in 2002 that ''Podokesaurus'' therefore had the peculiar distinction of being the dinosaur that vanished twice. The German paleontologist

Friedrich von Huene Friedrich von Huene, born Friedrich Richard von Hoinigen, (March 22, 1875 – April 4, 1969) was a German paleontologist who renamed more dinosaurs in the early 20th century than anyone else in Europe. He also made key contributions about v ...

was the last to study and describe the holotype specimen, in a 1914 publication before it was destroyed (he had studied it at Yale before Talbot's description was published). While the college's fossil collections were almost entirely destroyed by the fire, its facilities and collections continued to grow and improve afterwards due to Talbot's efforts. No other unequivocal ''Podokesaurus'' specimens have since been found, but cast replicas of the type specimen remain at the Peabody Museum of Natural History and the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 int ...

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

. ''Podokesaurus'' received little further attention until new and abundant fossils of ''

'' were discovered in the late 1940s, and the anatomy of small

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

dinosaurs became clearer; the American paleontologists

Edwin Harris Colbert Edwin Harris "Ned" Colbert (September 28, 1905 – November 15, 2001)O'Connor, Anahad ''The New York Times'', November 25, 2001. was a distinguished American vertebrate paleontologist and prolific researcher and author. Born in Clarinda, Iowa, h ...

and Donald Baird compared ''Podokesaurus'' with ''Coelophysis'' in 1958, using the casts of the former. Along with the sauropodomorph ''

Anchisaurus ''Anchisaurus'' is a genus of basal sauropodomorph dinosaur. It lived during the Early Jurassic Period, and its fossils have been found in the red sandstone of the Portland Formation, Northeastern United States, which was deposited from the He ...

'', ''Podokesaurus'' was among the first substantial collections of dinosaur skeletal material known from the East Coast of North America. Apart from a tooth (assigned to ''Coelophysis'' in 1976), all other Early Jurassic theropod records on the East Coast are footprints. In 2021, ''Podokesaurus'' and ''Anchisaurus'' were proposed as contenders for

of Massachusetts by Representative Jack Patrick Lewis, with ''Podokesaurus'' winning the online poll. On May 2, 2022, Governor

Charlie Baker Charles Duane Baker Jr. (born November 13, 1956) is an American politician and businessman serving as the 72nd governor of Massachusetts since 2015. A member of the Republican Party, Baker was a cabinet official under two governors of Massach ...

signed a law making it the official state dinosaur.

Description

The preserved body of the only known ''Podokesaurus'' fossil was long. Lull estimated the complete length of ''Podokesaurus'' to have been , the neck accounting for , the back for , the (the vertebrae of the pelvic region) for , and the tail for . Von Huene estimated the animal to have been long, with the tail accounting for about , more than 1.5 times the rest of the skeleton together. Colbert estimated the animal's length at about . In 1995, the writer Jan Peczkis estimated ''Podokesaurus'' to have weighed , through pelvic height determination (based on von Huene's measurements). The paleontologist Gregory S. Paul estimated it to have weighed in 2016 (based on a 1 m length estimate). Talbot stated in 1937 that those scientists who had seen the specimen did not think it was a young individual as there were no indications of

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck ...

that would turn to bone with age, while Paul thought it was possibly juvenile. In general, the animal was lightly constructed, with hollow bones. As a

, it would likely have been similar in build to for example ''Coelophysis'', being slender, long-necked, and with sharp, recurved teeth. Since few other small theropods were known at the time ''Podokesaurus'' was described, it was mainly compared to the later genera ''Compsognathus'', '' Ornitholestes'', and '' Ornithomimus'', which were thought related. Due to the fragmentary nature of the ''Podokesaurus'' specimen and the fact that it is lost, the identity and shape of some of its bones are today unclear. As only casts of the specimen now remain, it is only possible to get a general impression of the preserved skeleton and its proportions. Talbot identified bone fragments next to the tail as skull bones because two of them were

bilaterally symmetric Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pl ...

, and one was broadly convex with a sulcus (or furrow) at the midline, and according to Lull, was possibly placed at the upper wall of the skull, not far from the . Lull thought other of these elements may have been part of the . Von Huene instead interpreted these bones as caudals from the middle of the tail.

Postcranial skeleton

The vertebrae were very light and hollow, and some were slightly concave at each end. The cervical vertebrae were relatively large in length and diameter compared to the dorsals, and had styliform (resembling a pen or bristle in shape) cervical ribs which were long, straight, and narrow, as in ''Anchisaurus''. The front dorsals were much shorter than the cervicals, then again increased in size towards the pelvis. They measured in length. The of the dorsals were narrow, high, and curved backwards, but not as expanded from front to back as in ''Compsognathus''. The dorsal ribs were strongly curved and very slender and hollow, reminiscent of those in ''

Saltopus ''Saltopus'' ("hopping foot") is a genus of very small bipedal dinosauriform containing the single species ''Saltopus elginensis'' from the late Triassic period of Scotland. It is one of the most famous Elgin Reptiles. Description ''Saltopus ...

'' and ''

Hallopus ''Hallopus'' was a prehistoric reptile, named in 1877 as a species of '' Nanosaurus'' and classified by O. C. Marsh in 1881 from the Late Jurassic Morrison Formation. Today though the animal is thought to be a pseudosuchian more closely related ...

'', the largest being long and wide. The (that connected with the ribs on each side of a vertebra) formed a circular arc downward from each side of a dorsal, extending about as far from the (the "body" of a vertebra) as the was high. The (processes that connected adjacent vertebrae) were well-developed. The centra were relatively longer than those of ''Ornithomimus'', while those of ''Compsognathus'' resembled those of ''Podokesaurus'' more, but were shorter. While the hind part of the tail was located some distance away from the rest of the skeleton, Lull believed it was in its natural position and that it would have been very long, the intermediate vertebrae having been swept away. The caudal vertebrae were very long and slender, and along with their (bones on the undersides of the caudals), resembled those of ''Ornitholestes''. A typical caudal was long and in diameter. The caudals were very similar in length and did not decrease in length until the last few in the succession. Just in front of the pubis there was a cluster of slender (abdominal ribs), the longest of which was long. The frontmost gastralia had broadened ends, which is often the condition in sternal ribs. The humerus was small and very delicate, long, less than half the length of the femur. It had a strong processus lateralis (a process directed to the side) above its lower end. Lull found it similar to that of ''Ornitholestes'', apart from the radial crest (that connected with the of the lower arm) not being as high, showing little muscular power. Von Huene estimated the radius to have been long. Lull found the hand more similar to that of ''Compsognathus'' than of ''Ornitholestes''. Only slender phalanx bones of the three fingers were preserved, including sharp, curved claws. Podokesaurus restoration

The pubis was very long, expanding both at the front and hind ends. It was wide and long, and its lower expansion was in diameter. Talbot found the pubis similar to that of the then undescribed '' Procompsognathus''. Lull argued that the pubis lay approximately in position in the fossil, pointing forwards. Heilmann instead believed the bone had been moved out of position before burial, and would have been directed backwards. Colbert and Baird suggested the pubis was directed forwards, but that it curved slightly upwards instead of downwards due to natural warping and cracking of the bone. The ischium was long, wide at the end closest to the body, and its slender shaft was in diameter, and somewhat thickened at its lower end. Lull found it similar to those of ''Compsognathus'' and ''Ornitholestes''. Below the (where the femur connects with the pelvis) there was a broad lamella running towards the pubis. The femur was slender, nearly straight, had thin walls, and was expanded at the back side of its lower end. It was long and in diameter just below the (a flange placed mid-length at the back of the femur). The fourth trochanter was strong, long and about high, and was situated past the middle of the shaft, towards the lower end. The

condyles A condyle (;Entry "condyle"
in
tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and me ...

, as seen in birds. The length of the metatarsals was , while their width was . The most complete pedal phalanx was very slender and long.

Classification

Early interpretations

When reading her preliminary description in 1910, Talbot suggested ''Podokesaurus'' to have been an "herbivorous dinosaur", but further work at Yale University showed that some bones had been incorrectly identified, and the ischium of the pelvis with a well-developed ridge was found to resemble that of ''Compsognathus''. She refrained from making a definite classification of the specimen in her 1911 description due to the lack of jaw and foot-bones which could have aided in this, but concluded it would have belonged to a "carnivorous dinosaur" based on the shape and position of the pubis, as well as the absence of a . She considered the fossil to be

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

in age (the first of the three

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

periods). In 1914, von Huene named the new

Podokesauridae, wherein he, in addition to ''Podokesaurus'', included ''Saltopus'', ''Procompsognathus'', ''Coelophysis'', and ''

Tanystropheus ''Tanystropheus'' (Greek ~ 'long' + 'hinged') is an extinct archosauromorph reptile from the Middle and Late Triassic epochs. It is recognisable by its extremely elongated neck, which measured long—longer than its body and tail combined. T ...

''. He placed this group under

Coelurosauria Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, t ...

, which at the time was used to include small theropods in general. Heilmann considered ''Podokesaurus'' very similar to the early bird ''

Archaeopteryx ''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird''), is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaīos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...

'' in 1913, and wondered why Talbot had not made any comparisons to it. He particularly found the legs and the pelvis, when the pubis was interpreted as pointing backwards (as in birds), similar to what it might look like in a bird ancestor, while considering Lull's reconstruction of a forward-directed pubis unlikely. He also found parts of the shoulder blade, forelimbs, and even tail bones similar to those of birds. He furthermore pointed to the presence of abdominal ribs and that the bones were hollow, and concluded that nothing precluded ''Podokesaurus'' from being a very primitive

, with not yet fused middle-foot bones. The only feature he found inconsistent with this interpretation was the short finger with a claw, if it was not instead part of a toe. He suggested that the issue could be determined if the skull, sternum, and were found in the rock, bones that would be important clues for classification. Heilmann wished for a clearer explanation of the placement of the middle-foot bones in relation to each other, and found it surprising that Lull's reconstruction of ''Podokesaurus'' showed an even more appressed middle-foot than was present in the later supposed descendant ''Ornithomimus'', which he thought would have developed a completely bird-like middle-foot by that time. Heilmann found ''Podokesaurus'' very unusual for a dinosaur from the Triassic, and thought it was one of the earliest bipedal vertebrates. He suggested that since it was so different from ''

Thecodontosaurus ''Thecodontosaurus'' ("socket-tooth lizard") is a genus of herbivorous basal sauropodomorph dinosaur that lived during the late Triassic period ( Rhaetian age). Its remains are known mostly from Triassic "fissure fillings" in South England. ' ...

'' and ''

Plateosaurus ''Plateosaurus'' (probably meaning "broad lizard", often mistranslated as "flat lizard") is a genus of plateosaurid dinosaur that lived during the Late Triassic period, around 214 to 204 million years ago, in what is now Central and Northern Eur ...

'', those may not have been dinosaurs, or ''Podokesaurus'' could instead have been related to ''Saltopus'' or parasuchians, but found its fossils too insufficient to say anything definite about the issue. Shufeldt elaborated on his and Heilmann's interpretation of the pubis in 1915, and stated the bone had probably been displaced during fossilization. He pointed out that if it had faced forward, it would have been in forcible contact with the abdominal ribs that would have been dangerous for internal organs during movement. Lull found Heilmann and Shufeldt's criticisms of his pelvis reconstruction probable in 1915. He listed Podokesauridae under the superfamily Compsognatha, and suggested ''Podokesaurus'' was perhaps ancestral to the later North American genera ''Ornitholestes'' and ''Ornithimimus''. In 1916, Heilmann pointed out that early dinosaurs, parasuchians, and

pterosaurs Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to 6 ...

all had similarities to birds, as well as to each other, and that Triassic reptiles like ''

Scleromochlus ''Scleromochlus'' (from el, σκληρός , 'hard' and el, μοχλός , 'lever') is an extinct genus of small pterosauromorph archosaurs from the Late Triassic period. The genus contains the type and only species ''Scleromochlus taylori'', ...

'', ''Saltopus'', and ''Podokesaurus'', were difficult to separate. He proposed that ''Podokesaurus'' and other bipedal reptiles from the Triassic were descended from

pseudosuchians Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to ...

(which many types of archosaurs were classified as at the time) that may have evolved bipedality by the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo ...

. He concluded that birds were descended from ornithosuchian pseudosuchians rather than from dinosaurs, due to their bipedality and bird-like legs. The paleontologist

Henry Fairfield Osborn Henry Fairfield Osborn, Sr. (August 8, 1857 – November 6, 1935) was an American paleontologist, geologist and eugenics advocate. He was the president of the American Museum of Natural History for 25 years and a cofounder of the American Euge ...

used ''Podokesaurus'' as an example of a "carnivorous dinosaur of the bird-like type" in 1917, while stating that similarities between birds and dinosaurs were due to

parallel evolution Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.Zhang, J. and Kumar, S. 1997Detection of convergent and paral ...

. The paleontologist

Franz Nopcsa von Felső-Szilvás Baron Franz Nopcsa von Felső-Szilvás (also Baron Nopcsa von Felső-Szilvás, Baron Nopcsa, Ferenc Nopcsa, báró felsőszilvási Nopcsa Ferenc, Baron Franz Nopcsa, and Franz Baron Nopcsa; May 3, 1877 – April 25, 1933) was a Hungarian aristoc ...

created the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus Genus ( plural genera ) is a taxonomic rank used in the biological classifica ...

Podokesaurinae in 1928, within which he included ''Podokesaurus'', ''

Procerosaurus ''Tanystropheus'' (Greek ~ 'long' + 'hinged') is an extinct archosauromorph reptile from the Middle and Late Triassic epochs. It is recognisable by its extremely elongated neck, which measured long—longer than its body and tail combined. Th ...

'', ''Saltopus'', and ''Tanystropheus''. Von Huene grouped ''Podokesaurus'', ''Coelophysis'', ''

Spinosuchus ''Spinosuchus'' (meaning "spined crocodile") is an extinct genus of trilophosaurid allokotosaur from the Late Triassic of Texas, southern United States. It has been assigned to a variety of groups over its history, from coelophysid dinosau ...

'', ''

Halticosaurus ''Halticosaurus'' (pron.:"HAL-tick-oh-SORE-us") is a dubious genus of theropod dinosaur from the late Triassic period (middle Norian stage, around 215.6–208 million years ago). It is known from a single fragmentary fossil specimen of ...

'', ''Saltopus'', '' Avipes'', and '' Velocipes'' in Podokesauridae in 1932.

Relation to ''Coelophysis''

Replica of coelurosaur bone casts from Middletown, Connecticut

In 1958, Colbert and Baird described a theropod specimen consisting of natural casts of bones in sandstone (probably formed when the bones were dissolved by acidic water, leaving molds of the bones), including a pubis, tibia, and some ribs. They found the specimen similar to ''Coelophysis'' and ''Podokesaurus'', referring to it as ''C.'' sp. (of unknown species). They considered the natural cast and ''Podokesaurus'' to be from the Portland Arkose of the Newark Group in the Connecticut valley. Though ''Podokesaurus'' was smaller than the others (being comparable in size to the smallest-known ''Coelophysis'' specimens), these researchers suggested that because it was so similar to them, this raised questions as to its validity. In 1964, Colbert synomymized ''Podokesaurus'' with ''Coelophysis'', (since the latter name was older), coining the new combination ''C. holyokensis''. He also suggested that the natural cast belonged to ''C. holyokensis''. Colbert stated that ''Podokesaurus'' could only be distinguished from ''Coelophysis'' by the neural spines of its vertebrae not being as long from front to back, and because the ischium differed in shape. He found these differences to be similar to those seen between modern reptile species within the same genus, and that they represented eastern (''C. holyokensis'') and western (''C. bauri'') species of the same genus. While he admitted that these conclusions were not ironclad, and that ''Podokesaurus'' may indeed have been distinct, he said the burden of proof should be on the proponents of such a view. In 1977, the paleontologists Paul E. Olsen and

Peter Galton Peter Malcolm Galton (born 14 March 1942 in London) is a British vertebrate paleontologist who has to date written or co-written about 190 papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosa ...

redated the Newark Supergroup (which the Portland Formation belongs to) to the Early Jurassic instead of the preceding Triassic as was previously thought. This was part of a study in which Olsen compared the fauna of various formations and concluded there had not been a sudden, widespread extinction event at the Triassic-Jurassic border, but that it had instead been gradual. Olsen stated in 1980 that while the exact provenance and systematic position of ''Podokesaurus'' will probably remain uncertain, the Portland Formation it was thought to be from was probably Early Jurassic in age, and therefore 15 million years younger than ''Coelophysis'' from the Triassic. Since features shared between ''Podokesaurus'' and ''Coelophysis'' are also known in other small theropods, such as '' Syntarsus'', Olsen suggested that ''Podokesaurus'' should be retained as a separate genus of indeterminate theropods, to avoid overextending the temporal range of ''Coelophysis''. He also applied this argument to the natural cast, regarding it as ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

'' (with uncertain relationships) among theropods rather than as ''Podokesaurus'' or ''Coelophysis''. The paleontologist Samuel P. Welles stated in 1984 that the family Podokesauridae had become a "catch-all" for most Triassic theropods. While he found ''Coelophysis'' the most similar to ''Podokesaurus'' among theropods, he thought the two differed greatly in that the fourth trochanter of the latter was below midheight on the femur (unlike the higher position in most other theropods), and its metatarsals were of equal length. The paleontologist Kevin Padian stated in 1986 that while Colbert's suggestion of synonymy was possible, the discernible similarities between ''Podokesaurus'' and ''Coelophysis'' were primitive theropod features, and the two were not as close in time as once thought. Paul said in 1988 that while the family Podokesauridae was still used for ''Coelophysis'' and kin, ''Podokesaurus'' was not based on good remains to begin with, and with only bad cast replicas remaining, he thought there would always be disagreement about the taxon. He found this to be too much ambiguity to put up with, and proposed the name Coelophysidae should be used instead (Halticosauridae, another contender, was also based on too fragmentary remains). In 1989, Colbert also doubted the synonymy of ''Podokesaurus'' with ''Coelophysis'', and that the natural casts belonged to the latter, due to their revised Early Jurassic ages, and he made no attempt to resolve the status of ''Podokesaurus'' due to the only specimen being lost. He retained the name Podokesauridae for the family. Coelophysis bauri mount

In 1990, the paleontologists Timothy Rowe and

Jacques Gauthier Jacques Armand Gauthier (born June 7, 1948 in New York City) is an American vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology. Life and career Gauthier is the so ...

considered Podokesauridae a

taxonomic waste-basket Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically define ...

, wherein taxa had been grouped based on

phenetic In biology, phenetics ( el, phainein – to appear) , also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually in morphology or other observable traits, regardless of their phylogeny or evolutionary re ...

resemblance and

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

division, and therefore under continuous revision and instability. They considered it possible that ''Podokesaurus'' and the natural cast specimen were ''Coelophysis'', but found that their similarities were not shared exclusively by them, but were ancestral features among theropods. They therefore agreed that the name ''Podokesaurus'' should be restricted to the holotype, and that it and the natural cast should be considered Theropoda ''incertae sedis''. In the same volume, the paleontologist

David B. Norman David Bruce Norman (born 20 June 1952 in the United Kingdom) is a British paleontologist, currently the main curator of vertebrate paleontology at the Sedgwick Museum, Cambridge University. From 1991 to 2011, Norman has also been the Sedgwick Mu ...

agreed with this assessment, and stated the features used to unite ''Podokesaurus'' with ''Coelophysis'' merely confirm that they were dinosaurs rather than establish a specific relation between them. The paleontologist

Thomas R. Holtz Thomas Richard Holtz Jr. (born September 13, 1965) is an American vertebrate palaeontologist, author, and principal lecturer at the University of Maryland's Department of Geology. He has published extensively on the phylogeny, morphology, ecomor ...

agreed in 1994 that the family name Podokesauridae should be replaced by Coelophysidae. By this time, the idea that small theropods should be grouped in Coelurosauria and large theropods in

Carnosauria Carnosauria is an extinct large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as '' G ...

was falling out of favor, and Coelophysoidea was considered a separate group of gracile, early theropods. The paleontologists

David B. Weishampel Professor David Bruce Weishampel (born November 16, 1952) is an American palaeontologist in the Center for Functional Anatomy and Evolution at Johns Hopkins University School of Medicine. Weishampel received his Ph.D. in Geology from the Unive ...

and Luther Young suggested ceratosaurian affinities for ''Podokesaurus'' in 1996. The paleontologist Ronald S. Tykoski and Rowe noted in 2004 that while ''Podokesaurus'' had coelophysoid features (such as a small, knob-like expansion on the lower part of the pubis), it did not have any derived traits that would unite it with ''Coelophysis''. They agreed with earlier researchers that the name ''Podokesaurus'' should be restricted to the holotype, and concluded that the natural cast may be a coelophysoid, but could not be identified beyond being a theropod. In 2004, the paleontologists Matthew T. Carrano and Scott D. Sampson stated that ''Podokesaurus'' was almost certainly a coelophysoid similar to ''Coelophysis''. It had coelophysoid features such as a long, downward curved pubis, that was longer than the ischium, and an additional

foramen In anatomy and osteology, a foramen (;Entry "foramen"
in

(opening) on the pubis, below the , but little more could be said about its

. Carrano and colleagues stated in 2004 that '' Segisaurus'' and ''Podokesaurus'' were among the latest-surviving coelophysoids, and that the

evolutionary radiation An evolutionary radiation is an increase in taxonomic diversity that is caused by elevated rates of speciation, that may or may not be associated with an increase in morphological disparity. Radiations may affect one clade or many, and be rapid ...

of this group may have ended by the latest part of the Early Jurassic. Also in 2004, the paleontologists Anthea Bristowe and Michael A. Raath listed ''Podokesaurus'' as a synonym of ''Coelophysis'' without elaboration. Tykoski rejected synonymy between the two in his 2005 dissertation, but left ''Podokesaurus'' out of his analysis. Paul suggested in 2016 that ''Podokesaurus'' may have formed the family Coelophysidae with ''Coelophysis'', '' Panguraptor'', and ''Procompsognathus''.

Paleobiology

Talbot suggested that the short, slender humerus, long, straight hindlimb bones, and the well-developed fourth trochanter of the femur indicated that ''Podokesaurus'' was bipedal. She found the fact that the tibia was much longer than the femur, that the metatarsals were very long, over half the length of the tibia, and the skeleton's light construction, were indicative of rapid locomotion. Talbot stated that Lull thought this was an adaptation to climatic conditions, as the animal must have been able to travel fast and far for water in its

semi-arid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi- ...

region. Talbot also reported a small piece of smooth, polished

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

among the ribs, and suggested it could have been a

gastrolith A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In oth ...

(stomach stone), and so the first time these were found in association with a carnivorous dinosaur. Von Huene agreed the stone was a gastrolith, distinct from the surrounding sandstone, and added it was long. Lull found the animal to have been essentially a slender,

cursorial A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. cheetah) or if it can keep a constant speed for a long distance (high endurance). "Cursorial" is often u ...

(adapted for running) animal, with carnivorous habits, but that the slenderness that made it swift also confined it to small prey. In 1932, von Huene proposed that small coelurosaurs had a jumping gait, due to their lower legs being longer than their upper legs, contrasting with the alternating steps of carnosaurs. With its large fourth trocanther, he thought ''Podokesaurus'' had probably abandoned this jumping gait, instead moving with rapid, alternating steps similar to

ratite A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites. The systematics ...

birds.

In 1982, the paleontologist

Richard A. Thulborn Richard Anthony (Tony) Thulborn is a British paleontologist. He is recognized as an expert in dinosaur tracks, and as one of the most productive paleontologists of his time. In 1982, Thulborn debunked the purported plesiosaur embryos discovered by ...

estimated the speed of various dinosaurs, based on the relationships between speed, gait, and body size of modern animals (mainly mammals). By extrapolating the stride length and cadence of ''Podokesaurus'', he estimated it could have run at about . He concluded that if a dinosaur could match a mammal in speed, it must have had similar levels of efficiency in

locomotor ability Animal locomotion, in ethology, is any of a variety of methods that animals use to move from one place to another. Some modes of locomotion are (initially) self-propelled, e.g., running, swimming, jumping, flying, hopping, soaring and gliding. Th ...

and physiology. He cautioned that comparison was difficult because dinosaur anatomy differed significantly from that of mammals and birds. Differences included the massive tails of dinosaurs, and hindlimb retractor muscles that originated behind the femur, while these muscles originate more forward in mammals and extant birds. Weishampel stated in 2006 that as a coelophysoid, ''Podokesaurus'' would have been a fleet-footed predator, with powerful forelimbs and grasping hands. Lull found that fossil footprints named '' Grallator cursorius'' agreed with the foot and stride of ''Podokesaurus''. These were abundant at a quarry in South Hadley (where they were found alongside large ''

Otozoum moodii ''Otozoum'' ("giant animal") is an extinct ichnospecies of fossilized sauropodomorph dinosaur footprints and other markings in sandstones. They were made by heavy, bipedal animals (probably dinosaurs) with a short stride that walked on four t ...

'' tracks), which he thought supported this identity. In 1926, Heilmann suggested that the foot of ''Procompsognathus'' was a better match for the ''G. cursorius'' tracks, due to the proportions of its toe bones. The paleontologist Wilhelm Bock stated in 1952 that while very similar ''Grallator'' tracks had been attributed to various small dinosaurs (such as ''Podokesaurus''), he considered such correlations too specific, and that the best that could be said was such tracks represented small coelurosaurians. The writer

Donald F. Glut Donald F. Glut (; born February 19, 1944) is an American writer, motion picture film director, and screenwriter. He is best known for writing the novelization of the second ''Star Wars'' film, ''The Empire Strikes Back''. Filmmaker Amateur car ...

suggested in 1997 that a slab with tracks from the

Brunswick Formation The Passaic Formation is a mapped bedrock unit in Pennsylvania, New Jersey, and New York. It was previously known as the Brunswick Formation since it was first described in the vicinity of New Brunswick, New Jersey. It is now named for the city of ...

of New York previously attributed to ''Coelophysis'' may instead have been produced by ''Podokesaurus'', based on its Jurassic age. This formation is now known as the Passaic Formation, and instead thought to be Late Triassic in age.

Paleoenvironment

The only known specimen of ''Podokesaurus'' is thought to have been collected from the Portland Formation (earlier known as the Portland Arkose) in the

Hartford Basin The Eastern North America Rift Basins are a series of sediment-filled '' aborted rifts'' created by large-scale continental extension. Their positions closely mirror the eastern coast of North America. Sediments and volcanic material from the ri ...

of Massachusetts. The age of this formation has long been unclear (it was thought to be Triassic until 1977), but it is currently thought to date to the

–

stages of the Early Jurassic, between 201 and 190 million years ago (earlier thought to be the

Pliensbachian The Pliensbachian is an age (geology), age of the geologic timescale and stage (stratigraphy), stage in the stratigraphic column. It is part of the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series an ...

–

Toarcian The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toar ...

stages). In 2016, the paleontologist Robert E. Weems and colleagues suggested the Portland Formation should be elevated to a

geological group In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into superg ...

within the Newark Supergroup (as the Portland Group), and thereby replacing the former name "Agawam Group". They also reinstated the Longmeadow Sandstone, where ''Podokesaurus'' was found, as a formation (within the uppermost Portland Group); it had earlier been considered identical to the Portland Formation. The Portland Group represents the uppermost part of the Newark Supergroup, and was deposited after the

Central Atlantic magmatic province The Central Atlantic magmatic province (CAMP) is the Earth's largest continental large igneous province, covering an area of roughly 11 million km2. It is composed mainly of basalt that formed before Pangaea broke up in the Mesozoic Era, near the ...

was formed during the end of the Triassic and the beginning of the Jurassic. The Longmeadow Sandstone consists of

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

(deposited by rivers and streams) red

mudstones Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' ...

, sandstones, conglomerates, minor red eolian (deposited by wind) sandstones and

siltstones Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

. Other animals known from the formation include the sauropodomorph dinosaur ''Anchisaurus'', the crocodylomorph ''

Stegomosuchus ''Stegomosuchus'' is an extinct genus of small protosuchian crocodylomorph. It is known from a single incomplete specimen discovered in the late 19th century in Lower Jurassic rocks of south-central Massachusetts, United States. It was ori ...

'', and fish such as ''

Acentrophorus ''Acentrophorus'' is an extinct genus of prehistoric ray-finned fish from the Permian and Triassic periods. Fossils have been found in Australia, Germany and the United Kingdom. It was the oldest known neopterygian. See also * Prehistoric ...

'' and ''

Semionotus ''Semionotus'' (from el, σημιον , 'mark' and el, νῶτος , 'back') is an extinct genus of ray-finned fish found throughout Northern Pangaea (North America and Europe) during the late Triassic The Triassic ( ) is a geologic period a ...

''. Dinosaur tracks include the

ichnogenera An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxa'' comes from the Greek ίχνος, ''ichnos'' meaning ''track'' and ταξις, ''taxis'' meaning ...

'' Anchisauripus'', '' Anomoepus'', ''

Eubrontes ''Eubrontes'' is the name of fossilised dinosaur footprints dating from the Late Triassic and Early Jurassic. They have been identified from France, Poland, Slovakia, Czech Republic, Italy, Spain, Sweden, Australia (Queensland), USA, India and ...

'', and ''Grallator''.

References

External links

Museum of Science, Boston – "Celebrate ''Podokesaurus holyokensis'' as the Massachusetts State Dinosaur"
24 minute video
Museum of Science, Boston – "Choosing the Massachusetts State Dinosaur"
49 minute video {{featured article Coelophysoids Hettangian life Sinemurian life Early Jurassic dinosaurs of North America Paleontology in Massachusetts Holyoke, Massachusetts Fossil taxa described in 1911 Taxa named by Mignon Talbot