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Anaschisma
Anaschisma
Anaschisma
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Anaschisma
Temporal range: Late Triassic, Carnian–Norian
Skeleton of Anaschisma at the AMNH
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Clade: Tetrapoda
Order: †Temnospondyli
Suborder: †Stereospondyli
Family: †Metoposauridae
Genus: †Anaschisma
Branson, 1905
Type species
†Anaschisma browni
Branson, 1905
Synonyms
Genus synonymy
  • Borborophagus Branson & Mehl, 1929
  • Buettneria Case 1922 (preoccupied)
  • Koskinonodon Branson & Mehl, 1929
Species synonymy
  • Anaschisma brachygnatha Branson, 1905
  • Borborophagus wyomingensis Branson & Mehl, 1929
  • Buettneria perfecta Case, 1922
  • Koskinonodon perfectus (Case, 1922)

Anaschisma ("ripped up") is an extinct genus of large temnospondyls. These animals were part of the family called Metoposauridae, which filled the crocodile-like predatory niches in the late Triassic.[1] It had a large skull about 62 centimetres (24 in) long,[2] and possibly reached 3 metres (9.8 ft) long.[3] It was an ambush hunter, snapping up anything small enough to fit in its huge jaws.[3] It was very common during the Late Triassic (Carnian-Norian age) in what is now the American Southwest.[4]

History of discovery

[edit]

Anaschisma was erected by Branson (1905) from two metoposaurid skulls from the Popo Agie Formation (Carnian) of Wyoming. The generic name Anaschisma ("ripped up") was not explained but would derive from Ancient Greek ἀνασχίζω [anaskhizo] "rip up, rend", likely alluding to the fragmented state of the original fossils noted by Branson: "The skulls were incased in a hard matrix of arenaceous shale, and had been broken in many pieces." The type species, A. browni, was coined for the skull UC 447, while a second nominal species, A. brachygnatha, was erected for the skull UC 448.[5] Moodie (1908) considered A. brachygnatha a junior synonym of A. browni, although Branson and Mehl (1929) retained the two species as distinct.[6][7] Colbert and Imbrie (1956) synonymized Anaschisma with the Newark Supergroup genus Eupelor but retained it as a valid Eupelor species endemic to the Popo Aggie Formation.[8] Chowdhury (1965) synonymized Anaschisma with Metoposaurus and sunk all North American metoposaurids from the Chinle and Dockum into browni.[9]

Hunt (1989) recovered Anaschisma as an advanced or highly derived form.[10] Some specimens attributed to Anaschisma from the Redonda Formation were renamed Apachesaurus by Hunt (1993).[11][12]

Koskinonodon

[edit]
Koskinonodon perfectus skull, now thought to belong to Anaschisma

The genus Koskinonodon was formerly named Buettneria by Case in 1922, but in 2007, B.D. Mueller realized that the name Buettneria had already been given to a bush cricket from the Republic of Congo by Karsch (1889), so he made the genus Koskinonodon the earliest available unpreoccupied name for the temnospondyl.[13] Lucas et al. (2007), however, petitioned the ICZN to suppress Karsch's name in favor of Case's name, citing evidence that the amphibian name is much more well known and widely used (the authors cited 75 uses of the name in scientific literature and books over the last 85 years), and that the bush cricket name had been seldom used in technical literature.[14] However, ICZN Opinion 2255 issued in 2010 rejected the petition.[15]

Known Koskinonodon fossils have been found in the United States, especially the Chinle Formation of Petrified Forest National Park and the Placerias Quarry in Arizona, the Garita Creek Formation of central New Mexico (the quarry at Lamy), the Petrified Forest Member of northern New Mexico, the Bluewater Creek Formation of western New Mexico, the New Oxford Formation of Pennsylvania, the Tecovas Formation of western Texas, and the Popo Agie Formation of the Chugwater Group of Wyoming.[16][7]

Synonymy of Koskinonodon with Anaschisma started when Romer (1947) proposed that Anaschisma was a senior synonym of Buettneria, Koskinonodon, and Borborophagus.[16] This was followed by Gee et al. (2019), where they redescribed the holotypes of the two nominal Anaschisma species, and then synonymized Koskinonodon, Buettneria and Borborophagus with Anaschisma.[17] The species B. bakeri which has long been assigned to the various synonyms of Anaschisma, was moved to its own genus, Buettnererpeton, in 2022.[18]

Description

[edit]
Size of Anaschisma (large) and Apachesaurus (small) compared to a human

The skull of Anaschisma differs from the skulls of other closely related organisms in a few key ways. It is wider overall and features eye sockets that are very anterior and forward oriented, more so than its contemporaries.[6] Also, the skull has prominent slime canals, which are used for transporting mucus, as well as large external nares.[19] In addition, the upper jaw is relatively weak and thin, used only for holding teeth.[19] Their large jaws could have held many teeth at once, maybe even over 100 on each side of the upper and lower jaws, but the actual number varies constantly over the animal's lifetime due to natural causes such as fighting, eating, disease, etc.[19] The sheer size of the skull is one of the most defining traits for the genus Anaschisma.[19]

Other more minor skull traits characterize Anaschisma as well: elongation of the lacrimal, shortening of the prefrontal, reduction of the interclavicle, and the most characteristic is the center lachrymal entering margin of the orbit.[3] While the shortened prefrontal is a characteristic of the family Metoposauridae, it is shorted even more in Anaschisma.[1] The interclavicle is reduced in the way that it has many hexagonal pits as well as grooves and ridges.[1] The skull of Anaschisma is also covered in this reticulate ornamentation.[20] Some researchers believe that Anaschisma has a shorter posterior process of the interclavicle, which may discriminate it from other closely related species, while others believe that there is not enough information to make that distinction.[1] Anaschisma also has ossified opisthotics, the more posterior of the bones surrounding the inner ear.[20]

Anaschisma had sharp, pointy teeth for catching and killing prey. They had marginal teeth as well as larger teeth on the palate, specifically palatine and ectopterygoid teeth.[1] They had two basic types: large with shallow grooves and small with deeper grooves. These grooves run lengthwise down the teeth and aided the animals in catching prey.[21] The teeth are elongated labio-lingually at their base and opposite, mesiodistally, at their tip. In the middle, they are not elongated either way but instead circular.[21] These dental adaptations enhanced the ability of Anaschisma to capture prey; the teeth are optimized for piercing prey and not allowing it to escape, resisting the bending force applied by the struggling organism, and propagating cracks in the hard parts of the object, such as bone, allowing for easier eating and digestion.[21]

Anaschisma had a wide, wedge-shaped, powerful tail to assist it with swimming, hunting and likely defense.[3] It was not long like the crocodiles of today, but more likely short and strong to enable it to quickly spring up from hiding and capture prey before it escapes.[3] The legs of Anaschisma display a sprawling stance and short legs with 4-digits on the front and 5 on the back limbs.[3] Anaschisma likely spent a lot of time motionless, waiting for prey, which these short legs were likely an adaptation to.[5]

Paleobiology

[edit]
Life restoration of Anaschisma chasing a fish

The hunting style of Anaschisma involved lying at the bottom of a shallow swamp, waiting for a fish, crustacean, smaller amphibian, or even a young phytosaur to wander by.[3] When it spotted prey, it used its huge jaws to engulf and consume them.[3] A few particular adaptations suggest Koskinonodon had this aquatic lifestyle. First, they had lateral lines formed by the sensory sulci. These are useful for detecting changes in water pressure made by the swimming motions of nearby organisms. Their sprawling limbs were also adapted for water. They would not move quickly or efficiently on land, although they may have done it to find another water pool with more food or other resource. Mass graves have been found, thought to be a result of a group of these animals gathering together in a withering water pool during a drought and all perishing because the water was never replenished.[19]

Paleoecology

[edit]

They lived mostly in the late Triassic; by the time the Jurassic began, most temnospondyls, Anaschisma included, were gone.[22] It is likely that they went extinct during the Triassic-Jurassic extinction event, along with the majority of other large amphibians, the class of Conodonts and 34% of all marine genera. It is unknown what caused this mass extinction; hypotheses include huge volcanic eruptions (the Central Atlantic magmatic province is a prime example), climate change, oceanic acidification, or an asteroid impact. It is known, however, that over half of the species living on Earth at that time went extinct from this event.[23] It lived alongside many other smaller amphibians, and its fossils are also commonly found with phytosaur fossils.[19][24] It was named in 1931 by Case. The best conditions for fossilization occur in river valleys or floodplains where deposition is occurring, and this animal likely lived in similar shallow, swampy habitats. As it follows, Anaschisma is famous for having extremely well preserved fossils, and they are often found in groups.[19]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Anaschisma

View on Grokipedia
from Grokipedia
Anaschisma is an extinct of large-bodied temnospondyl amphibians in the Metoposauridae, known from the (– stages) of . These aquatic predators, characterized by their flattened skulls, forward-positioned eyes, and laterally compressed tails, inhabited freshwater environments such as rivers and lakes across what is now the western and . The was originally established by Branson and Mehl in 1929 to describe fragmentary material from the Popo Agie Formation in , with the A. browni later recognized as encompassing previous synonyms like A. brachygnatha due to intraspecific variation rather than distinct taxa. Fossils of Anaschisma have been recovered from multiple localities, including the in and , the New Oxford Formation in , and the Popo Agie Formation in , indicating a widespread distribution during a time of diverse non-marine ecosystems. Reaching estimated lengths of approximately 3 meters, these amphibians possessed robust skulls up to 65 cm long equipped with conical teeth suited for capturing fish and smaller vertebrates, while their weak limbs and lateral-line sensory systems underscored their adaptation to an almost exclusively aquatic lifestyle. Mass mortality assemblages, such as those preserving dozens of individuals, suggest that Anaschisma populations were vulnerable to environmental stresses like seasonal droughts, contributing to their common occurrence in bone beds. Phylogenetically, Anaschisma represents one of the more derived metoposaurids, clustering with other North American taxa in analyses that highlight regional within the group despite their overall morphological conservatism. The genus provides key insights into the of floodplains, where it likely occupied top predator or roles alongside early dinosaurs and crocodylomorphs, before the of metoposaurids near the end of the .

Taxonomy

Etymology and classification

The genus name Anaschisma was coined by E. B. Branson in 1905, with no explicit etymology provided in the original description. Subsequent analyses suggest it derives from the Greek words ana- (meaning "up" or "back") and schisma (meaning "cleft" or "split"). Anaschisma is classified as a genus within the family Metoposauridae, a group of stereospondyl temnospondyls characterized by their large body size, dorsoventrally flattened skulls, and adaptations for aquatic lifestyles. Metoposauridae belongs to the suborder Stereospondyli and the broader order Temnospondyli, a diverse clade of extinct batrachomorph tetrapods that dominated aquatic and semi-aquatic environments from the Late Carboniferous to the Early Cretaceous periods. Temnospondyli encompasses approximately 200 genera and over 300 species, exhibiting a range of morphologies from small, terrestrial forms to giant, fully aquatic predators, and is distinguished by features such as infolded tooth enamel (labyrinthodonty) and complex palatal structures. Phylogenetically, Anaschisma occupies a derived position within Metoposauridae, supported by shared derived traits including a broad, flattened with posteriorly positioned orbits and otic notches indicative of piscivorous feeding adaptations. Cladistic analyses, incorporating morphological characters from cranial and postcranial elements, recover Anaschisma in a polytomous basal assemblage with other North American metoposaurids, highlighting the family's overall morphological conservatism during the . This placement underscores Metoposauridae's role as a specialized, short-lived radiation confined to the – stages of the .

Species and synonymy

The genus Anaschisma is currently recognized to contain a single valid , A. browni, which serves as the . This was originally described from the Popo Agie Formation (Chugwater Group) in , based on a skull ( specimen UC 447) collected near Willow Creek. The description dates to 1905, establishing A. browni as the senior for several later-named taxa within the . A second species originally assigned to Anaschisma, A. brachygnatha, was described from the same formation and locality based on another (UC 448). However, a 2019 redescription synonymized A. brachygnatha with A. browni, attributing previously noted differences—such as narrower proportions and relatively larger orbits—to intraspecific variation and ontogenetic stages rather than diagnostic traits. The genus Koskinonodon, previously recognized as distinct and known from the in and , was fully synonymized with Anaschisma in 2019, with its type species K. perfectus (and related taxa like K. princeps and Borborophagus wyomingensis) considered junior synonyms of A. browni. This revision was based on the absence of distinguishing morphological features between the holotypes, including shared cranial characteristics such as the lacrimal entering the orbital margin, posteriorly tapering frontals, a maxilla-prefrontal contact, and the jugal terminating at the anterior level of the orbital margin, as well as postcranial traits like large reticulate ornamentation on dermal elements. Ontogenetic variation had previously led to the misinterpretation of these specimens as representing separate genera. Material from the New Oxford Formation in , initially described as indeterminate metoposaurid, was reassigned to A. browni in 2021, extending the species' known distribution eastward and confirming its presence across multiple formations in .

History of discovery

Initial descriptions

The genus Anaschisma was first established in by E.B. Branson based on fossil material collected from the Popo Agie Formation ( stage of the ) in , . The , A. browni, was named from a partial (AMNH 6758) and associated vertebrae discovered near Lake Creek in Fremont County, representing one of the earliest documented metoposaurid temnospondyls from North American continental deposits. Branson also described a second species, A. brachygnatha, from a fragmentary and dentary (AMNH 6759), noting its labyrinthodont and overall similarity to other large amphibians but emphasizing the limited preservation that hindered full morphological analysis. Subsequent early collections in the 1920s added fragmentary postcranial elements, such as additional vertebrae and limb bones, from the same localities, which were initially assigned to the family Metoposauridae due to shared features like a flattened and piscivorous adaptations. These specimens, including material collected by and others, reinforced the genus's placement among non-marine temnospondyls but suffered from incompleteness, leading to an incomplete understanding of its anatomy and variability at the time. The scarcity of articulated material meant early interpretations focused primarily on cranial fragments, with comparisons drawn to European metoposaurids like . In 1929, E.B. Branson and M.G. Mehl introduced the genus Koskinonodon as a replacement name for the preoccupied Buettneria perfecta (originally described by E.C. Case in 1922 from the in ), based on more robust skull and skeletal material from the same deposits. This taxon was initially regarded as distinct from Anaschisma owing to its larger size—skulls exceeding 80 cm in length—and heavier postcranial build, suggesting potential ecological differences in the fluvial environments of the . The synonymy of Koskinonodon with Anaschisma was proposed much later, reflecting ongoing taxonomic refinements.

Recent redescriptions and synonymies

In 2019, Bryan M. Gee, William G. Parker, and Adam D. Marsh provided a comprehensive redescription of the type material of Anaschisma browni and A. brachygnatha from the Popo Agie Formation of , utilizing an updated phylogenetic framework for metoposaurids. This analysis reappraised the holotypes and associated specimens, demonstrating that previously proposed diagnostic differences between Anaschisma and Koskinonodon fell within ranges of intraspecific variation; it also synonymized A. brachygnatha as a junior of A. browni attributable to ontogenetic and intraspecific differences. This led to the synonymization of Koskinonodon perfectus as a junior of A. browni, with Anaschisma retaining precedence due to its earlier description. In 2021, Bryan M. Gee and Steven E. Jasinski described well-preserved metoposaurid fossils from the New Oxford Formation at the Zions View locality in , assigning them to A. browni based on shared cranial and postcranial features, marking the first confirmed record of the genus in eastern . The material, including multiple partial skulls and postcranial elements, was differentiated from the sympatric Calamops paludosus through detailed comparisons, significantly expanding the known geographic range of A. browni across the continent and establishing it as one of the most widespread metoposaurids. These studies employed advanced techniques, such as CT scanning of new and historical specimens, to distinguish ontogenetic variation from intergeneric differences, clarifying taxonomic boundaries within Metoposauridae. Consequently, they refined understandings of metoposaurid diversity, highlighting regional endemism patterns and the need for further investigation of eastern North American assemblages to resolve phylogenetic relationships.

Description

Skull morphology

The skull of Anaschisma is characteristically large and flattened, typical of metoposaurids, with a triangular outline in dorsal view that broadens posteriorly and narrows anteriorly, reflecting adaptations for a piscivorous lifestyle. Known specimens reach up to 42 cm in midline length from the to the postparietals, though estimates for larger individuals suggest up to approximately 65 cm. The features prominent ornamentation of pits and ridges, with large orbits positioned laterally and somewhat anteriorly, measuring approximately 60 mm in diameter and forming anteroposteriorly elongated ovals that enhance for predation. The external nares are oval-shaped and positioned anteriorly on the , while the temporal fenestrae are expansive, accommodating robust adductor musculature. Key diagnostic features include deep palatal vacuities, manifested as large interpterygoid vacuities separated by a narrow, uniform-width cultriform process of the parasphenoid, which distinguish Anaschisma from relatives like Apachesaurus that exhibit a narrower process. The parietals are elongated and slender, sub-rectangular in shape, narrowest anteriorly, and framing a round pineal foramen in their posterior third, contributing to the elongated posterior table. The quadrate is robust and blocky, longest medially and tapering laterally, providing a strong articulation for the . Exoccipitals form a significant portion of the occipital region, with distinct condyles that articulate with the vertebral column to support neck musculature, though some specimens show taphonomic damage to the . Compared to other metoposaurids such as Koskinonodon, Anaschisma has a relatively shorter snout and the contacting the orbital margin, with the prefrontal and lacrimal terminating at similar levels anteriorly. Ontogenetic variations are evident in proportions, with juvenile specimens displaying proportionally larger orbits and nares relative to width, as well as less expansion of the temporal lobes. Size differences among adults have prompted hypotheses of , though this remains unconfirmed without additional evidence. These cranial traits link to the postcranial via the exoccipital condyles but are primarily diagnostic for genus-level identification within Metoposauridae.

Postcranial skeleton

The postcranial skeleton of Anaschisma is known from fragmentary remains, primarily isolated elements associated with cranial material from the Popo Agie Formation of , indicating an overall body plan adapted for an aquatic lifestyle. The estimated total length of the animal reached 2–3 meters, with a barrel-shaped trunk that provided in shallow-water environments. The consists of robust, amphicoelous vertebral centra, with neural spines that form a low ridge along the dorsal surface, resembling a fin-like structure for stability during swimming. Up to 50 presacral vertebrae have been inferred from comparable metoposaurid specimens, though complete sequences are not preserved for Anaschisma itself. The features short, paddle-like limbs suited to in , with reduced digits numbering 4–5 in the manus, reflecting adaptations for minimal terrestrial mobility. The pectoral and pelvic girdles include a broad and ilium, which supported and muscle attachment for limb movement. The tail is characterized by elongated chevrons that enhanced lateral undulation for forward thrust. The from the skull articulate with the robust , forming a stable junction for head movement in predatory contexts.

Paleobiology

Locomotion and feeding

Anaschisma, as a metoposaurid temnospondyl, exhibited a primarily aquatic lifestyle, with locomotion dominated by lateral undulation of its long, laterally flattened serving as the main propulsion mechanism during . The 's flexible structure, supported by elongated neural arches and chevrons forming a caudal , facilitated efficient thrust in water, while the stiff limited lateral trunk bending. Its limbs functioned as flippers for steering and stability, with symmetrical, simultaneous movements akin to those in plesiosaurs or sea turtles, indicating reduced terrestrial capability due to gracilized and paddle-like elements such as the laterally flattened and rotated heads. Feeding in Anaschisma was adapted for an predation strategy, with its broad and anteropositioned orbits enabling it to lie in wait near the water bottom before launching rapid lateral head strikes at passing prey. The conical marginal teeth and wide gape suggest a piscivorous diet focused on and smaller aquatic tetrapods, employing direct bilateral biting to capture soft-bodied prey rather than feeding. Histological and biomechanical analyses of related metoposaurids indicate that this feeding mode allowed for generalist predation in variable freshwater environments, with robust jaw muscles supporting efficient prey seizure. Sensory adaptations in Anaschisma included large orbits for enhanced vision in low-light riverine conditions and a well-developed system evident in skull grooves, which detected vibrations from nearby prey or environmental cues. These features, combined with the skull's posterior taper and robust postcranial elements like the tail, underscore its role as an opportunistic aquatic predator.

Growth and ontogeny

Fossil evidence indicates that Anaschisma exhibited significant size variation throughout its , with juveniles possessing skull lengths of approximately 15 cm, corresponding to estimated total body lengths of around 0.5–1 m, while adults attained skull lengths exceeding 60 cm and total body lengths up to 3 m. This range reflects a substantial increase in body size during development, consistent with the large-bodied nature of metoposaurids. While much histological data derives from related metoposaurids like , similar patterns are inferred for Anaschisma. Bone histology from related metoposaurids, such as , reveals rapid early growth characterized by highly vascularized woven bone tissue in thick zones, transitioning to slower, punctuated growth in maturity marked by compact annuli and rest lines. Growth rings suggest individuals reached adulthood around 7 years of age, with longevity unknown. Ontogenetic changes in Anaschisma included alterations in proportions, such as negative in size relative to overall length and a narrowing of the cultriform process, indicating a transition to more robust cranial architecture in adults. morphology shifted from smaller, more conical in juveniles to larger marginal teeth in adults adapted for piscivory. death assemblages, including monodominant bonebeds, suggest potential semelparity, with adults possibly aggregating for a single breeding season before mortality, akin to some modern amphibians.

Paleoecology and distribution

Habitat and environment

Fossils of Anaschisma are primarily known from the Popo Agie Formation in , the in the , and the New Oxford Formation in the , all representing (–) nonmarine deposits. These formations document fluvial-lacustrine settings characterized by river channels, floodplains, lakes, and marshes, with sediments dominated by mudstones, siltstones, and sandstones indicative of low-energy depositional environments conducive to the preservation of aquatic and semi-aquatic vertebrates. The Popo Agie Formation, in particular, consists of reddish siltstones, mudstones, and minor sandstones interpreted as overbank and crevasse-splay deposits within a fluvial system, interspersed with lacustrine limestones suggesting shallow freshwater bodies. Environmental reconstructions indicate a with seasonal , supporting river systems that periodically flooded mudflats and lowlands. Bonebeds of Anaschisma, such as the monodominant assemblage from the lower purple unit, are preserved in fine-grained siltstones and mudstones, with taphonomic evidence of minimal transport pointing to mass mortality events, likely from in drying pools or flash floods during seasonal dry periods. Similarly, the reflects a continental fluvial-floodplain-lacustrine , with Anaschisma remains occurring in overbank mudstones and siltstones from river valleys and associated wetlands. Sedimentological features, including crevasse-splay sands and lacustrine deltas, suggest episodic flooding in a humid, monsoonal that transitioned to more seasonal , fostering environments with mudflats and ephemeral water bodies. Taphonomic patterns in Chinle Anaschisma accumulations, often in fine-grained overbank deposits, imply concentration through low-energy entrapment during flood events or in isolated pools. In the New Oxford Formation, part of the rift-related , Anaschisma fossils are found in a sequence of sandstones, conglomerates, and shales deposited in alluvial-fluvial to lacustrine settings within an active basin. This formation correlates with similar sequences like the Lockatong Formation, indicating seasonal riverine and ponded environments under a tropical paleoclimate with variable humidity. Preservation occurs in finer clastics, supporting inferences of mass death assemblages in or marginal lacustrine contexts, consistent with the genus's aquatic lifestyle.

Biogeography and faunal associations

Anaschisma exhibits a broad geographic distribution across , with definitive records from western localities in (Popo Agie Formation), , , and ( and equivalents), extending eastward to (New Oxford Formation). This span covers approximately 3,000 km from the western interior to the eastern seaboard, highlighting the connectivity of fluvial and riverine systems that facilitated dispersal during the to stages. In terms of faunal associations, Anaschisma commonly co-occurs with pseudosuchians and early archosaurs in floodplain and lacustrine deposits. Within the Chinle Formation, it shares assemblages with phytosaurs such as Machaeroprosopus and Smilosuchus, aetosaurs including Desmatosuchus and Paratypothorax, and nascent dinosaurs like coelophysoids; these interactions reflect a diverse vertebrate community in semi-aquatic to terrestrial margins. In the Popo Agie Formation, Anaschisma is part of metoposaurid-dominated amphibian faunas alongside primitive phytosaurs like Angistorhinus and Paleorhinus, as well as therapsids such as Placerias hesternus. As a large-bodied temnospondyl, Anaschisma served as an apex aquatic predator in ecosystems, preying on and smaller tetrapods while dominating amphibian assemblages. Its presence alongside phytosaurs and early crocodylomorphs, such as Hesperosuchus in the , suggests niche overlap and potential competition for resources in riverine habitats. The genus's extensive North American range, coupled with metoposaurid occurrences across Pangea, underscores the group's successful dispersal, likely enabled by humid climatic episodes and expansive fluvial networks during the .

References

  1. https://www.tandfonline.com/doi/full/10.1080/14772019.2019.1602855
  2. https://www.cambridge.org/core/journals/journal-of-paleontology/article/description-of-the-metoposaurid-anaschisma-browni-from-the-new-oxford-formation-of-pennsylvania/0614F772BC3DE5E6B97200456373C492
  3. https://doi.org/10.1080/14772019.2019.1602855
  4. https://doi.org/10.1080/02724634.2021.1922067
  5. https://doi.org/10.1017/jpa.2021.30
  6. https://www.journals.uchicago.edu/doi/10.1086/621258
  7. https://core.ac.uk/download/pdf/324160543.pdf
  8. https://digitallibrary.amnh.org/server/api/core/bitstreams/187dc998-b440-44ae-a531-245ae88a07ce/content
  9. https://www.researchgate.net/publication/249023658_Koskinonodon_Branson_and_Mehl_1929_a_replacement_name_for_the_preoccupied_temnospondyl_Buettneria_Case_1922
  10. https://pmc.ncbi.nlm.nih.gov/articles/PMC5442151/
  11. https://www.palaeontologia.pan.pl/PP64/PP-64-029-143.pdf
  12. https://peerj.com/articles/4426/
  13. https://www.researchgate.net/publication/319377000_A_juvenile_Koskinonodon_perfectus_Temnospondyli_Metoposauridae_from_the_Upper_Triassic_of_Arizona_and_its_implications_for_the_taxonomy_of_North_American_Metoposaurids
  14. https://www.prehistoric-wildlife.com/species/anaschisma/
  15. https://www.eurekalert.org/news-releases/546427
  16. https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/histological-characteristics-of-the-vertebral-intercentra-of-metoposaurus-diagnosticus-temnospondyli-from-the-upper-triassic-of-krasiejow-upper-silesia-poland/23D9FC76330DDE4E8743DE2EF3C6FEF0
  17. https://pmc.ncbi.nlm.nih.gov/articles/PMC11964259/
  18. https://pubs.usgs.gov/bul/1917p/report.pdf
  19. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1227&context=usgsstaffpub
  20. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0317325
  21. https://pubs.usgs.gov/bul/1787w/report.pdf
  22. https://www.researchgate.net/publication/333435753_Redescription_of_Anaschisma_Temnospondyli_Metoposauridae_from_the_Late_Triassic_of_Wyoming_and_the_phylogeny_of_the_Metoposauridae
  23. https://digitalrepository.unm.edu/cgi/viewcontent.cgi?article=1353&context=eps_etds
  24. https://www.researchgate.net/publication/248058387_The_vertebrate_fauna_of_the_Upper_Triassic_Chinle_Formation_in_northern_Arizona
  25. https://pubs.usgs.gov/of/1971/0333/report.pdf
  26. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0064203
  27. https://www.researchgate.net/publication/349815950_Biochronology_of_Late_Triassic_Metoposauridae_Amphibia_Temnospondyli_and_the_Carnian_pluvial_episode
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