Paleobiota of the Chinle Formation explained

The Chinle Formation is an extensive geological unit in the southwestern United States, preserving a very diverse fauna of Late Triassic (primarily Norian-age) animals and plants. This is a list of fossilized organisms recovered from the formation.

Amniotes

Archosauromorphs

Crurotarsans

See main article: Archosaurs of the Chinle Formation.

Other Archosauromorphs

Non-crurotarsan Archosauromorphs of the Chinle Formation
Genus	Species	State	Member	Abundance	Notes	Images
Crosbysaurus^[1]	C. harrisae	Arizona Utah	Blue Mesa		An archosauriform represented only by teeth. It is treated as indeterminate archosauriform remains by Irmis in 2005. It was originally thought to be an ornithischian dinosaur.
Doswellia^[2]	cf. D. kaltenbachi	Arizona	Blue Mesa	Osteoderms, vertebrae, rib and hip fragments.	A doswelliid archosauriform.
Puercosuchus^[3]	P. traverorum	Arizona	Blue Mesa	Two monodominant bonebeds.	A carnivorous azendohsaurid archosauromorph.
Rugarhynchos^[4]	R. sixmilensis	New Mexico	Bluewater Creek	Skull and postcranial fragments.	A doswelliid archosauriform. Originally described as a species of Doswellia,^[5] but subsequently transferred to a separate genus.
Syntomiprosopus^[6]	S. sucherorum	Arizona	Blue Mesa or Sonsela	Two to four individuals from a single quarry.	A short-faced archosauriform, possibly an unusual early-diverging crocodylomorph. Appears convergent with some Late Cretaceous notosuchians.
Tanystropheidae^[7]	Indeterminate	New Mexico	Petrified Forest	Vertebrae	Moderately-sized tanystropheid vertebrae from the Hayden Quarry, likely representing a new taxon closely related to Langobardisaurus and Tanytrachelos.
Tanytrachelos^[8]	Indeterminate / T. ahynis	New Mexico Arizona	Petrified Forest Mesa Redondo	Cervical rib, calcaneum, etc.	A small tanystropheid represented by several hundred fossil specimens.
Tecovasaurus^[9]	T. murryi	Arizona	Mesa Redondo		An unknown amniote represented by scattered teeth formerly believed to be from an ornithischian dinosaur. Later discoveries of similar teeth in pseudosuchians meant that these could no longer be regarded as anything more specific than some kind of archosauriform.
Trilophosaurus^[10]	T. buettneri^[11]	Arizona	Blue Mesa
	T. dornorum^[12]	Arizona	Sonsela
	T. jacobsi^[13]	Arizona	Blue Mesa Mesa Redondo
	T. phasmalophos^[14]	Arizona	Sonsela
Vancleavea^[15]	V. campi	Arizona New Mexico	"Siltstone"^[16] Petrified Forest Sonsela Blue Mesa		A strange aquatic carnivorous archosauriform, represented by both articulated skeletons and scattered elements like osteoderms and vertebrae.

Other amniotes

Miscellaneous amniotes of the Chinle Formation
Genus	Species	State	Member	Abundance	Notes	Images
Acallosuchus^[17]	A. rectori	Arizona	Blue Mesa	Known only from a partial skull.	A strange neodiapsid whose bones were heavily ornamented "with subtriangular knobs... running the length of the bones." Even these ornamentations were ornamented "with additional grooves." It is too bizarre to be currently classified as anything more than a probable diapsid.
Ancistronychus^[18]	A. paradoxus	Arizona	Sonsela	Manual unguals (hand claws).	A drepanosaur related to Drepanosaurus.
Avicranium^[19]	A. renestoi	New Mexico	'Siltstone'	Skull and neck vertebrae.	A drepanosaur with a toothless skull and a flexible neck owing to the heterocoelous (saddle-shaped) articular surfaces of the vertebral centrae. The neural spines are anteroposteriorly short and strongly anterodorsally inclined. These features closely resemble those of Drepanosaurus.
Colognathus^[20]	C. obscurus	Arizona	Blue Mesa	Known only from a jaw fragment and some isolated teeth.	Originally believed to be a fish, Colognathus was a strange amniote with distinctive fluted teeth.
Dolabrosaurus	D. aquatilis	New Mexico	Petrified Forest	Articulated vertebral and limb material.	A drepanosaur.
Drepanosaurus^[21]	D. unguicaudatus	New Mexico	Petrified Forest		A drepanosaur.
Kataigidodon^[22]	K. venetus	Arizona	Blue Mesa	Partial dentaries.	A non-mammalian eucynodont.
Kraterokheirodon^[23]	K. colberti	Arizona	Petrified Forest Blue Mesa or Mesa Redondo	Known only from two teeth.	A possible cynodont. Although they share some similarities with cynodont teeth, the teeth of Kraterokheirodon are very distinctive and can't be confidently referred to a known amniote group.
Palacrodon^[24]	Indeterminate	Arizona	Blue Mesa	Jaw fragments.	A diapsid reptile of uncertain phylogenetic placement with unusual broadened teeth. More complete fossils of this genus from the Fremouw Formation of Antarctica suggest that it was an arboreal saurian.^[25]
Placerias^[26]	P. hesternus	Arizona	Blue Mesa Mesa Redondo	Known from several hundred remains, but very rare outside of the highly concentrated Placerias Quarry.	A placeriine stahleckeriid dicynodont.
Skybalonyx^[27]	S. skapter	Arizona	Blue Mesa	Manual unguals (hand claws).	A drepanosaur which likely had a burrowing lifestyle.
Uatchitodon^[28]	U. schneideri^[29]	Arizona^[30]	Mesa Redondo	Known in Chinle from only a single tooth. The presence of venom channels is consistent with other known Uatchitodon specimens, although the Chinle specimen's channels are unique in being "completely enclosed under the surface of the crown."	A reptile of unknown affinities, probably a carnivorous archosauromorph with venomous capabilities.
Whitakersaurus^[31]	W. bermani	New Mexico	"Siltstone"		A rhynchocephalian found at Ghost Ranch.
Indeterminate procolophonid^[32]	Indeterminate	Utah

Amphibians

Amphibians of the Chinle Formation
Genus	Species	State	Member	Abundance	Notes	Images
Apachesaurus^[33]	A. gregorii	Arizona	Owl Rock Petrified Forest Blue Mesa	Common in the Owl Rock and Petrified forest members. Blue Mesa remains are fragmentary.	A metoposaurid temnospondyl which is a junior synonym of Anaschisma
Anaschisma^[34] ^[35]	A. browni^[36]	Arizona	Owl Rock Petrified Forest Sonsela Blue Mesa Mesa Redondo	A. browni is "possibly the most common tetrapod fossil in the lower Chinle", although its presence in the upper Chinle is "unclear".	A metoposaurid temnospondyl. Koskinonodon was erected for the species "Buettneria" perfecta when it was discovered that the latter genus was preoccupied. Gee et al., 2017 then synonymised it with Anaschisma.
Chinlestegophis^[37]	C. jenkinsi	Colorado			A temnospondyl in the group Stereospondyli, related to Rileymillerus from the Dockum Group of Texas. Possibly a stem-caecilian according to one analysis, though others have disputed this finding
Funcusvermis^[38]	F. gilmorei	Arizona	Blue Mesa	Numerous jaw fragments, as well as a referred maxillopalatine, vertebra, and femur	A stem-caecilian
Salientia indet.^[39]	Indeterminate	Arizona	Sonsela Member Blue Mesa Member	Five bones: four ilia and a partial maxilla.	A stem-group frog. Might be more closely related to crown-group frogs (anurans) than to Early Triassic taxa Triadobatrachus and Czatkobatrachus.

Cartilaginous fish

Chondrichthyans of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Acrodus^[40]	Indeterminate	Arizona	Petrified Forest^[41] Sonsela Mesa Redondo	Only a single tooth is known.	A hybodontiform shark.
Lonchidion^[42]	L. humblei	Arizona	Blue Mesa Mesa Redondo		A hybodontiform shark. Lonchidion remains are common throughout the Carnian microvertebrate sites of the American southwest.
Palaeoxyris	P. humblei^[43]	Arizona	Blue Mesa	Several specimens	An egg capsule of a freshwater hybodont shark.
Phoebodus^[44]	Indeterminate	Arizona	Mesa Redondo	Only a single specimen has been recovered from the formation.
Reticulodus^[45]	R. synergus	Arizona	Owl Rock Petrified Forest Sonsela		The crown of its tooth bears a "reticulating ornamentation on [its] occlusal surface[.]" Reticulodus remains are common throughout the Norian microvertebrate sites of the American southwest.
Mooreodontus^[46] ^[47]	M. moorei	Arizona	Blue Mesa Mesa Redondo	Common in the lower Chinle Formation's microvertebrate localities.	A xenacanthiform shark.

Lobe-finned fish

Lungfish

Dipnoans (lungfish) of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes
Arganodus^[50]	A. dorotheae
	Indeterminate	Arizona	Petrified Forest Sonsela Blue Mesa Mesa Redondo	Arganodus toothplates are the most common fossil in the formation from a non-tetrapod. They are evenly distributed across strata, although some individual localities have very high concentrations.	Most Chinlean Arganodus fossils are isolated tooth plates.
Ceratodus	C. dorotheae				Named by Case in 1921, in the 1980s it was referred to Arganodus.

Ray-finned fish

Actinopterygians (ray-finned fish) of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Australosomus^[51]	Indeterminate^[52]	Arizona	Mesa Redondo	Known only from two vertebrae.
Cionichthys^[53]	C. dunklei	Colorado Utah			A member of Redfieldiiformes.
Hemicalypterus	H. weiri	Utah	Church Rock Member		A member of Dapediiformes.^[54]
Lasalichthys^[55]	L. hillsi	Utah			A member of Redfieldiiformes.
	Indeterminate^[56]	Arizona	Petrified Forest Blue Mesa Mesa Redondo		Represented by isolated scales.
Lophionotus^[57]	L. sanjuanensis	Utah	Church Rock Member		A member of Semionotiformes.
	L. chinleana^[58]	Utah	Church Rock Member		A member of Semionotiformes.
Saurichthys^[59]	Indeterminate	Arizona	Upper Blue Mesa Member		A member of Saurichthyiformes.
Synorichthys	S. stewarti	Colorado Utah			A member of Redfieldiiformes.
Tanaocrossus	T. kalliokoskii	Colorado			An enigmatic actinopterygian.
Turseodus^[60]	T. dolorensis	Colorado			A member of Palaeonisciformes.
	Indeterminate^[61]	Arizona	Owl Rock Petrified Forest Sonsela Blue Mesa	Common.	Isolated scales from Chinle microvertebrate sites commonly have Turseodus-like ridges, however that feature is not unique to Turseodus and in 2005 Irmis advised researchers to regard them as indeterminate palaeoniscid remains.

Plants

The Chinle Formation has a diverse flora of plant megafossils, though they are concentrated in only a few sites with suitable conditions. One of the most diverse floral communities is found near Fort Wingate, New Mexico. Paleobotanists have traditionally placed the Fort Wingate plant beds into the Monitor Butte Member, though more recently they are placed within the Bluewater Creek Formation, a subunit of the Chinle Formation first defined in 1989.^[62] Some Fort Wingate plant fossils belong to the "Lake Ciniza beds", a localized patch of grey mudstone corresponding to an ancient lake.

Another productive areas for plant fossils is Petrified Forest National Park in Arizona. Though petrified wood could be found through the entire stratigraphy of the park, most other plant fossils are exclusive to greenish mudstone layers adjacent to the Newspaper Rock sandstone bed in the Blue Mesa Member (formerly known as the "Lower Petrified Forest").

Conifers are the most common and diverse plants, including petrified wood and leafy branches from massive trees (Araucarioxylon, Pagiophyllum) as well as smaller shrubby forms (Pelourdea). Cycad and bennettitalean leaves and other remains make up a significant portion of the flora (Zamites, Nilssoniopteris, Williamsonia, etc.). Ferns (Cladophlebis, Phlebopteris, Clathropteris, Cynepteris, etc.) are abundant, with a range of growth habits including low shrubs, tree ferns, and palm-like fronds comparable to their modern relatives. Sphenophytes (horsetails: Neocalamites, Equistetites, Schizoneura, etc.) have low diversity but high abundance, and the largest Neocalamites fossils in the Chinle Formation could reach up to 6 meters (20 feet) in height. "Seed ferns" (Chilbinia, Marcouia?) ginkgophytes (Baiera), and small lycopods (Chinlea, Selaginella) were present but uncommon. The flora is rounded out by unusual low-growing gymnosperms such as Sanmiguelia (an angiosperm-like shrub), Dechellyia, and Dinophyton (possible relatives of Gnetales).

The floral composition of the Chinle Formation (and other parts of Late Triassic North America) seem to shift with changes in climate over time. The lowest parts of the Chinle, such as the Shinarump Conglomerate, are dominated by the bennettitalean Eoginkgoites alongside the first occurrence of other persistent plants such as Phlebopteris, Equisetites, and most common conifer species. Subsequent subunits (such as the Blue Mesa Member, Monitor Butte Member, and Bluewater Creek Formation) are much more diverse, with a wide array of humidity-adapted plants making up the typical Chinle flora. This second floral zone is characterized by Dinophyton, a common but enigmatic shrubby gymnosperm. Plant fossils are rare in the upper part of the Chinle Formation, which was presumably much drier than the lower part. In these later layers, by far the most common plant fossils belong to Sanmiguelia (an endemic of southwestern North America) alongside conifers and horsetails.^{[63] [64]}

Gymnosperms

Gymnosperms of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Araucariorhiza^[65]	A. joae	Arizona^[66]	"Petrified Forest" sensu lato	Uncommon	Roots of conifers similar to modern Araucariaceae. Possibly from the same plant as Araucarioxylon arizonicum.
Araucarioxylon^[67]	A. arizonicum, A. sp.^[68]	Arizona Utah New Mexico^[69] ^[70]	"Siltstone" Petrified Forest Sonsela Blue Mesa Bluewater Creek (formerly Monitor Butte) Agua Zarca Sandstone	Abundant	Petrified trunks of large conifers possibly related to modern Araucariaceae.^[71] State fossil of Arizona.
Araucarites	A. rudicula^[72]	Arizona New Mexico	Blue Mesa Monitor Butte	Very rare	Large female conifer cones similar to those of araucariacean conifers.
Aricycas^[73]	A. paulae	Arizona	Blue Mesa (= "Lower Petrified Forest")	Moderately common	Pinnate cycad leaves
Baiera	B. arizonica	Arizona New Mexico^[74]	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (= "lower red member", formerly Monitor Butte)	Uncommon	Ginkgophyte leaves
Brachyphyllum	B. sp,B. hegewaldia^[75]	Arizona New Mexico Utah	Blue Mesa (= "Lower Petrified Forest") Agua Zarca Sandstone Shinarump Temple Mountain	Uncommon	Conifer leaves and shoots
Carpolithus	C. chinleana	Arizona	Blue Mesa (= "Lower Petrified Forest")	Rare	Seeds of uncertain affinities
Cephalotaxopsis	C. sp.	Arizona			Conifer foliage
Charmorgia	C. dijolli	Arizona	"Petrified Forest" sensu lato	Rare	Short cycad stems
Chilbinia^[76]	C. lichii	Arizona	Shinarump	Rare	An archaic seed fern with seeds and leaves more similar to Carboniferous-Permian seed ferns than to Triassic forms.
Creberanthus	C. bealeii	Arizona	Blue Mesa	Very rare	Pollen-bearing cones similar to those of some extinct "pteridosperms" (seed ferns). Associated with Alisporites opii, a common palynomorph.
Dadoxylon	D. chaneyi	Arizona	"Petrified Forest" sensu lato	Very rare	Possible cordaitalean conifer wood.
Dechellyia^[77]	D. gormanii	Arizona^[78] New Mexico^[79]	Bluewater Creek (formerly Monitor Butte) Monitor Butte	Uncommon	An enigmatic gymnosperm with narrow pinnate leaves, "clasping" leaf-like sporophylls, and winged seeds. Some leaves are affected by galls, similar to those formed by eriophyid mites in modern plants.
Dinophyton	D. spinosus^[80]	Arizona New Mexico^[81]	Blue Mesa (= "Lower Petrified Forest") Monitor Butte Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte)	Common	An unusual gymnosperm combining needle-covered shoots with seed-bearing structures having the form of "pinwheel"-like clusters of tubular needles. Possibly related to Gnetales.
Elatocladus	E. puercoensis	Arizona	Blue Mesa	Uncommon	Leaf-bearing conifer shoots
Eoginkgoites	E. sp.,E. davidsonii^[82]	Arizona Utah	Shinarump	Common within its small stratigraphic range	A bennettitalean with palm-shaped fronds similar to some ginkgo species.
Ginkgoites	G. sp.	Arizona	Blue Mesa	Rare	A ginkgophyte
Lindleycladus	L. arizonicus	Arizona	Blue Mesa	Uncommon	Conifer shoots bearing Podozamites leaves. Formerly known as Podozamites arizonicus.
Lyssoxylon	L. grigsbyi	Arizona New Mexico	"Petrified Forest" sensu lato Bluewater Creek (formerly Monitor Butte)	Rare	Cycad trunks
Marcouia	M. neuropteroides	Arizona New Mexico	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (formerly Monitor Butte) Monitor Butte	Uncommon	Fern-like gymnosperm leaves of uncertain affinities. Some leaves are affected by feeding traces including crescent-shaped marginal incisions and oval-shaped holes. These were probably produced by beetles or orthopterans (grasshoppers and kin).
Masculostrobus	M. clathratus	Arizona	Monitor Butte	Locally common	A pollen-bearing cone associated with lattice-shaped Equisetosporites chinleana pollen.
Nilssoniopteris	N. ciniza	Arizona New Mexico Utah	"Petrified Forest" sensu lato Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte) Shinarump	Uncommon	Large smooth-edged bennettitalean leaves, some of which were originally identified as Macrotaeniopteris magnifola.
Otozamites	O. macombii	New Mexico	Agua Zarca Sandstone	Uncommon	Bennettitalean leaves
Pagiophyllum	P. sp.,P. duttonia, P. navajoensis, P. readiana, P. zuniana, P. simpsonii^[83]	Arizona Colorado New Mexico	"Middle Dolores" "Petrified Forest" sensu lato Sonsela Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte) Agua Zarca Sandstone	Locally very common	Conifer leaves
Palissya	P. sp.,P. diffusa, P. sphenolepis	New Mexico Utah	Monitor Butte Agua Zarca Sandstone Shinarump	Uncommon	Conifer leaves and shoots
Pelourdea	P. poleoensis	Utah Colorado New Mexico	"Siltstone" "Middle Dolores" Poleo Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte) Shinarump	Common	A shrubby conifer with strap-like leaves arranged around a single narrow stem.
Podozamites	P. sp.,P. emmonsi, P. lanceolatus	Arizona Utah	Blue Mesa (= "Lower Petrified Forest") Shinarump Temple Mountain	Uncommon	Conifer leafs and shoots
Pramelreuthia	P. dubielli,^[84] P. yazzi	Arizona New Mexico Utah	Blue Mesa Monitor Butte	Rare	Gymnosperm microsporophylls (pollen-bearing organs)
Pterophyllum	P. sp.,P. braunianum	Arizona Utah	Shinarump	Uncommon	Bennettitalean leaves
Samaropsis	S. sp.,S. puerca	Arizona	Blue Mesa (= "Lower Petrified Forest")	Uncommon	Seeds of uncertain affinities
Sanmiguelia	S. lewisii	Arizona^[85] Utah^[86] Colorado	Rock Point Owl Rock "Middle Dolores" Petrified Forest Sonsela Blue Mesa	Common	An unusual palm-like shrub, controversially suggested to be a relative or predecessor of angiosperms (flowering plants).
Schilderia	S. adamanica	Arizona	Petrified Forest	Rare	Petrified stems of a conifer or gnetalean
Williamsonia	W. nizhonii^[87]	New Mexico	Bluewater Creek (= "lower red member", formerly Monitor Butte)	Rare	A bennettitalean "flower" (female cone)
Woodworthia	W. arizonica	Arizona	Petrified Forest	Uncommon	Stems and petrified wood of a conifer related to A. arizonicum.^[88]
Zamites	Z. sp.,Z. occidentalis, Z. powellii	Arizona^[89] Utah^[90] New Mexico	Church Rock? Owl Rock? Blue Mesa (= "Lower Petrified Forest") Sonsela Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte) Monitor Butte Agua Zarca Shinarump	Very common	Bennettitalean leaves. Some leaves exhibit feeding traces, including sharp diagonal marginal traces and slot-like non-marginal traces. These traces were probably left by beetles. Zamites powellii was formerly known as Otozamites powellii.

Ferns

Ferns of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Apachea	A. arizonica	Arizona	"Petrified Forest"	Rare	Dipteridacean fern leaves, possibly damaged specimens of Clathropteris walkeri.
Cladophlebis	C. daughertyi,^[91] C. subfalcata, C. yazzia, C. sp.	Arizona New Mexico Utah	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (= "lower red member", formerly Monitor Butte) Monitor Butte Shinarump	Very common	Large sterile fern leaves of uncertain affinities
Clathropteris	C. walkeri	Arizona New Mexico	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (= "lower red member", formerly Monitor Butte)	Common	Dipteridacean fern leaves
Cynepteris	C. sp.,C. lasiophora	Utah Arizona New Mexico	Church Rock? Owl Rock? Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (= "lower red member", formerly Monitor Butte) Monitor Butte	Common	Bipinnate fern leaves previously identified as Lonchopteris. Some leaves are affected by crescent-shaped marginal feeding traces, probably from beetles or orthopterans (grasshoppers and kin).
Itopsidema^[92]	I. vancleavi	Arizona	Sonsela	Uncommon	Stems of large osmundacean tree ferns. Some stems show evidence of being bored by oribatid mites.^[93]
Phlebopteris	P. smithii,P. utensis	Arizona^[94] New Mexico Utah	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (= "lower red member" / "Ciniza Lake beds", formerly Monitor Butte) Shinarump	Common	Matoniacean fern leaves with a palmate structure
Sphenopteris	S. arizonica	Arizona^[95]	Blue Mesa (= "Lower Petrified Forest")	Uncommon	Sterile fern leaves of uncertain affinities. Some show evidence for marginal damage by insect feeding traces.
Todites	T. fragilis	Arizona New Mexico	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (="lower red member", formerly Monitor Butte)	Uncommon	Osmundacean fern leaves
Wingatea	W. plumosa	Arizona New Mexico	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek (="lower red member", formerly Monitor Butte)	Rare	Gleicheniacean fern leaves previously named as a species of Coniopteris.

Other plants

Other plants of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Chinlea	C. sp.,C. campii	Arizona^[96]	"Petrified Forest" sensu lato	Uncommon	Small lycopod stems similar to shrubby forms such as Pleuromeia.
Equisetites	E. sp.,E. bradyi	Arizona Utah New Mexico	Blue Mesa (= "Lower Petrified Forest") Bluewater Creek ("Ciniza Lake beds", formerly Monitor Butte) Shinarump	Common	A horsetail indistinguishable from modern Equisetum.
Equisetocalis^[97]	E. muirii	Arizona	Blue Mesa	Concentrated in a narrow stratigraphic range (the Newspaper Rock sandstone bed)	Small three-dimensional horsetail stems preserved in pyrite nodules.
Isoetites	I. circularis	Arizona	"Petrified Forest" sensu lato	Rare	Quillwort shoots
Lycostrobus	L. chinleana	Arizona	Blue Mesa (= "Lower Petrified Forest")	Rare	Horsetail cones sometimes placed in the genus Equicalostrobus
Neocalamites	N. sp.,N. virginiensis	Arizona Utah Colorado^[98] New Mexico	"Siltstone" Church Rock? Owl Rock? "Petrified Forest" sensu lato Bluewater Creek (= "lower red member" / "Ciniza Lake beds", formerly Monitor Butte)	Common	Stems and leaves of a giant sphenophyte (horsetail)
Schizoneura	S. harrisii	New Mexico	Bluewater Creek (formerly Monitor Butte)	Uncommon	Stems and leaves of a large sphenophyte (horsetail) more typical of Southern Hemisphere plant assemblages.
Selaginella	S. anasazia	Arizona	Monitor Butte	Uncommon	A low-growing lycopsid similar to modern broad-leaved species of Selaginella, such as S. kraussiana

Arthropods

Arthropods of the Chinle Formation
Genus	Species	State	Stratigraphic position	Abundance	Notes	Images
Enoplocytia	E. porteri^[99]	Arizona	Sonsela?	Single well-preserved fossil	An erymid crayfish
Paleoscolytus^[100]	P. divergus	Arizona	Sonsela		A species of bark beetle, evidenced by trace fossils of tracks made on A. arizonicum specimens.

Bibliography

• Irmis, R. B. 2005. The vertebrate fauna of the Upper Triassic Chinle Formation in northern Arizona. p. 63-88. in S.J. Nesbitt, W.G. Parker, and R.B. Irmis (eds.) 2005. Guidebook to the Triassic formations of the Colorado Plateau in northern Arizona: Geology, Paleontology, and History. Mesa Southwest Museum Bulletin 9.
• Mueller, B. D. and Parker, W. G. 2006. A new species of Trilophosaurus (Diapsida: Archosauromorpha) from the Sonsela Member (Chinle Formation) of Petrified Forest National Park, Arizona. In W. G. Parker, S. R. Ash & R. B. Irmis (eds.), A Century of Research at Petrified Forest National Park, 1906-2006: Geology and Paleontology. Museum of Northern Arizona Bulletin 62:119-125
• Mueller, B.D.. 2007. Koskinonodon Branson and Mehl, 1929, a replacement name for the preoccupied temnospondyl Buettneria Case, 1922. Journal of Vertebrate Paleontology. 27. 1. 225. 10.1671/0272-4634(2007)27[225:KBAMAR]2.0.CO;2. 85763026.
• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .

Notes and References

1. "Vertebrate Fauna; Archosauriformes; Crosbysaurus harrisae," Irmis (2005) p. 71
2. William G. Parker . Sterling J. Nesbitt . Adam D. Marsh . Ben T. Kligman . Kenneth Bader . 2021 . First occurrence of Doswellia cf. D. kaltenbachi (Archosauriformes) from the Late Triassic (middle Norian) Chinle Formation of Arizona and its implications on proposed biostratigraphic correlations across North America during the Late Triassic . Journal of Vertebrate Paleontology . 41 . 3 . e1976196 . 10.1080/02724634.2021.1976196 . 243474578 .
3. Marsh . Adam D. . Parker . William G. . Nesbitt . Sterling J. . Kligman . Ben T. . Stocker . Michelle R. . 2022 . Puercosuchus traverorum n. gen. n. sp.: a new malerisaurine azendohsaurid (Archosauromorpha: Allokotosauria) from two monodominant bonebeds in the Chinle Formation (Upper Triassic, Norian) of Arizona . Journal of Paleontology . en . 96 . S90 . 1–39 . 10.1017/jpa.2022.49 . 0022-3360 . free.
4. Brenen M. Wynd . Sterling J. Nesbitt . Michelle R. Stocker . Andrew B. Heckert . 2020 . A detailed description of Rugarhynchos sixmilensis, gen. et comb. nov. (Archosauriformes, Proterochampsia), and cranial convergence in snout elongation across stem and crown archosaurs . Journal of Vertebrate Paleontology . 39 . 6 . e1748042 . 10.1080/02724634.2019.1748042 . 219917329 .
5. Lucas. Spencer. Heckert. Andrew. A new species of the enigmatic archosauromorph Doswellia from the Upper Triassic Bluewater Creek Formation, New Mexico, USA. Palaeontology. 2012. 55. 6. 1333–1348. 10.1111/j.1475-4983.2012.01200.x. 15431716 . en.
6. Heckert. A. B. . Nesbitt . S. J. . Stocker . M. R. . Schneider. V. P. . Hoffman . D. K. . Zimmer . B. W. . 2021 . A new short-faced archosauriform from the Upper Triassic Placerias/Downs' quarry complex, Arizona, USA, expands the morphological diversity of the Triassic archosauriform radiation . . 108 . 4 . Article 32 . 10.1007/s00114-021-01733-1 . free . 34213630 . 8253714 . 2021SciNa.108...32H .
7. Pritchard . Adam C. . Turner . Alan H. . Nesbitt . Sterling J. . Irmis . Randall B. . Smith . Nathan D. . 2015-03-04 . Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae . Journal of Vertebrate Paleontology . en . 35 . 2 . e911186 . 10.1080/02724634.2014.911186 . 130089407 . 0272-4634.
8. "Vertebrate Fauna; Archosauromorpha; Tanytrachelos sp.," Irmis (2005) p. 70
9. "Vertebrate Fauna; Archosauriformes; Tecovasaurus murryi," Irmis (2005) p. 71
10. "Vertebrate Fauna; Archosauromorpha; Trilophosaurus buettneri, Trilophosaurus jacobsi, Trilophosaurus sp." Irmis (2005) p. 70
11. "Vertebrate Fauna; Archosauromorpha; Trilophosaurus buettneri," Irmis (2005) p. 70
12. "Abstract," Mueller and Parker (2006) p. 119
13. "Vertebrate Fauna; Archosauromorpha; Trilophosaurus jacobsi," Irmis (2005) p. 70
14. Ben T. Kligman . Adam D. Marsh . Sterling J. Nesbitt . William G. Parker . Michelle R. Stocker . 2020 . New trilophosaurid species demonstrates a decline in allokotosaur diversity across the Adamanian-Revueltian boundary in the Late Triassic of western North America . Palaeodiversity . 13 . 1 . 25–37 . 10.18476/pale.v13.a3 . free .
15. "Vertebrate Fauna; Archosauriformes; Vancleavea campi," Irmis (2005) p. 71
16. Nesbitt . S.J. . Sterling Nesbitt . Stocker . M.R. . Michelle R. Stocker . Small . B.J. . Bryan J. Small . Downs . A. . Alex Downs . November 26, 2009 . The osteology and relationships of Vancleavea campi (Reptilia: Archosauriformes) . Zoological Journal of the Linnean Society . 157 . 4 . 814–864 . 10.1111/j.1096-3642.2009.00530.x . free.
17. "Vertebrate Fauna; Reptilia incertae sedis; Acallosuchus rectori," Irmis (2005) pp. 69-70
18. Gabriel S. Gonçalves . Christian A. Sidor . 2019 . A new drepanosauromorph, Ancistronychus paradoxus n. gen. et sp., from the Chinle Formation of Petrified Forest National Park, Arizona, USA . PaleoBios . 36 . ucmp_paleobios_46203 .
19. Pritchard. Adam C.. Nesbitt. Sterling J.. 2017-10-01. A bird-like skull in a Triassic diapsid reptile increases heterogeneity of the morphological and phylogenetic radiation of Diapsida. Royal Society Open Science. en. 4. 10. 170499. 10.1098/rsos.170499. 29134065. 5666248. 2017RSOS....470499P. 2054-5703.
20. "Vertebrate Fauna; Parareptilia; Colognathus obscurus," Irmis (2005) p. 69
21. Pritchard. Adam C.. Turner. Alan H.. Irmis. Randall B.. Nesbitt. Sterling J.. Smith. Nathan D.. 2016-10-24. Extreme Modification of the Tetrapod Forelimb in a Triassic Diapsid Reptile. Current Biology. en. 26. 20. 2779–2786. 10.1016/j.cub.2016.07.084. 27693141. 0960-9822. free.
22. Ben T. Kligman . Adam D. Marsh . Hans-Dieter Sues . Christian A. Sidor . 2020 . A new non-mammalian eucynodont from the Chinle Formation (Triassic: Norian), and implications for the early Mesozoic equatorial cynodont record . Biology Letters . 16 . 11 . Article ID 20200631 . 10.1098/rsbl.2020.0631 . 33142088 . 7728676 .
23. "Vertebrate Fauna; Amniota incertae sedis; Kraterokheirodon colberti," Irmis (2005) p. 69
24. Ben T. Kligman . Adam D. Marsh . William G. Parker . 2018 . First records of diapsid Palacrodon from the Norian, Late Triassic Chinle Formation of Arizona, and their biogeographic implications . Acta Palaeontologica Polonica . 63 . 1 . 117–127 . 10.4202/app.00426.2017 . free .
25. Jenkins . Kelsey M. . Meyer . Dalton L. . Lewis . Patrick J. . Choiniere . Jonah N. . Bhullar . Bhart-Anjan S. . 2022 . Re-description of the early Triassic diapsid Palacrodon from the lower Fremouw formation of Antarctica . Journal of Anatomy . 241 . 6 . 1441–1458 . 10.1111/joa.13770. 36168715 . 9644968 . 252565757 . December 1, 2024 .
26. "Vertebrate Fauna; Synapsida; Placerias hesternus," Irmis (2005) p. 82
27. Jenkins . Xavier A. . Pritchard . Adam C. . Marsh . Adam D. . Kligman . Ben T. . Sidor . Christian A. . Reed . Kaye E. . Kaye Reed . 2020 . Using manual ungual morphology to predict substrate use in the Drepanosauromorpha and the description of a new species . Journal of Vertebrate Paleontology . 40 . 5 . e1810058 . 10.1080/02724634.2020.1810058 . free.
28. Listed as cf. Uatchitodon sp. in "Vertebrate Fauna; Reptilia incertae sedis; Cf. Uatchitodon sp," Irmis (2005) p. 69
29. Mitchell . Jonathan S. . Heckert . Andrew B. . Sues . Hans-Dieter . 2010 . Grooves to tubes: evolution of the venom delivery system in a Late Triassic "reptile" . Naturwissenschaften . 97 . 12 . 1117–1121 . 2010NW.....97.1117M . 10.1007/s00114-010-0729-0 . 21060984 . 10093308.
30. "Vertebrate Fauna; Reptilia incertae sedis; Cf. Uatchitodon sp," Irmis (2005) p. 69
31. Heckert. Andrew B.. Lucas. Spencer G.. Rinehart. Larry F.. Hunt. Adrian P.. 2008-07-01. A New Genus and Species of Sphenodontian from the Ghost Ranch Coelophysis Quarry (upper Triassic: Apachean), Rock Point Formation, New Mexico, Usa. Palaeontology. en. 51. 4. 827–845. 10.1111/j.1475-4983.2008.00786.x. 1475-4983. free.
32. Nicholas C. Fraser . Randall B. Irmis . David K. Elliott . 2005 . A procolophonid (Parareptilia) from the Owl Rock Member, Chinle Formation of Utah, USA . Palaeontologia Electronica . 8 . 1 . Article Number 8.1.13 .
33. "Vertebrate Fauna; Temnospondyli; Apachesaurus gregorii" Irmis (2005) pp. 67-68
34. Mueller (2007)
35. Gee . Bryan M. . Parker . William G. . Marsh . Adam D. . Redescription of Anaschisma (Temnospondyli: Metoposauridae) from the Late Triassic of Wyoming and the phylogeny of the Metoposauridae . Journal of Systematic Palaeontology . 2020 . 18 . 3 . 233–258 . 10.1080/14772019.2019.1602855. 190896742 .
36. "Vertebrate Fauna; Temnospondyli; Buettneria perfecta" Irmis (2005) p. 67. Note that Koskinonodon was listed under the preoccupied (see Mueller 2007) name Buettneria in the preceding reference.
37. Jason D. Pardo . Bryan J. Small . Adam K. Huttenlocker . 2017 . Stem caecilian from the Triassic of Colorado sheds light on the origins of Lissamphibia . Proceedings of the National Academy of Sciences of the United States of America . 114 . 27 . E5389–E5395 . 10.1073/pnas.1706752114 . 28630337 . 5502650 . 2017PNAS..114E5389P . free .
38. Kligman . Ben T. . Gee . Bryan M. . Marsh . Adam D. . Nesbitt . Sterling J. . Smith . Matthew E. . Parker . William G. . Stocker . Michelle R. . 2023-01-25 . Triassic stem caecilian supports dissorophoid origin of living amphibians . Nature . 614 . 7946 . en . 102–107 . 10.1038/s41586-022-05646-5 . 36697827 . 9892002 . 256272986 . 1476-4687. 10919/113568 . free .
39. Michelle R. Stocker . Sterling J. Nesbitt . Ben T. Kligman . Daniel J. Paluh . Adam D. Marsh . David C. Blackburn . William G. Parker . 2019 . The earliest equatorial record of frogs from the Late Triassic of Arizona . Biology Letters . 15 . 2 . Article ID 20180922 . 10.1098/rsbl.2018.0922 . 30958136 . 6405462 . 10919/87931 .
40. "Vertebrate Fauna; Chondrichthyes; Acrodus sp." Irmis (2005) p. 65
41. The Petrified Forest and Sonsela Acrodus specimens are actually Reticulodus. See "Vertebrate Fauna; Chondrichthyes; Acrodus sp." Irmis (2005) p. 65 for details.
42. "Vertebrate Fauna; Chondrichthyes; Lonchidion humblei," Irmis (2005) p. 65
43. Fischer . Jan . Axsmith . Brian J. . Ash . Sidney R. . 2010-03-01 . First unequivocal record of the hybodont shark egg capsule Palaeoxyris in the Mesozoic of North America . Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen . en . 255 . 3 . 327–344 . 10.1127/0077-7749/2009/0028 . 0077-7749.
44. "Vertebrate Fauna; Chondrichthyes; Phoebodus sp." Irmis (2005) p. 65
45. "Vertebrate Fauna; Chondrichthyes; Reticulodus synergus," Irmis (2005) p. 65
46. "Vertebrate Fauna; Chondrichthyes; 'Xenacanthus' moorei," Irmis (2005) p. 64
47. Bhat . Mohd Shafi . Ray . Sanghamitra . Datta . P. M. . 2018-09-01 . A new assemblage of freshwater sharks (Chondrichthyes: Elasmobranchii) from the Upper Triassic of India . Geobios . 51 . 4 . 269–283 . 10.1016/j.geobios.2018.06.004 . 0016-6995.
48. Listed as cf. Chinlea sp. in "Vertebrate Fauna; Temnospondyli; Cf. Chinlea sp." Irmis (2005) p. 67
49. "Vertebrate Fauna; Temnospondyli; Cf. Chinlea sp." Irmis (2005) p. 67
50. "Vertebrate Fauna; Temnospondyli; Arganodus sp." Irmis (2005) p. 67
51. Listed as "cf. Australosomus" in "Vertebrate Fauna; Osteichthyes; Cf. Australosomus sp." Irmis (2005) p. 66-67
52. "Vertebrate Fauna; Osteichthyes; Cf. Australosomus sp." Irmis (2005) p. 66-67
53. Bobb Schaeffer . 1967 . Late Triassic fishes from the western United States . Bulletin of the American Museum of Natural History . 135 . 285–342 . 2246/1125 .
54. Sarah Z. Gibson . 2016 . Redescription and Phylogenetic Placement of †Hemicalypterus weiri Schaeffer, 1967 (Actinopterygii, Neopterygii) from the Triassic Chinle Formation, Southwestern United States: New Insights into Morphology, Ecological Niche, and Phylogeny . PLOS ONE . 11 . 9 . e0163657 . 10.1371/journal.pone.0163657 . 27657923 . 5033578. 2016PLoSO..1163657G . free .
55. Listed as "cf. Lasalichthyes" in "Vertebrate Fauna; Osteichthyes; Cf. Lasalichthyes sp." Irmis (2005) p. 66
56. "Vertebrate Fauna; Osteichthyes; Cf. Lasalichthyes sp." Irmis (2005) p. 66
57. Sarah Z. Gibson . 2013 . A new hump-backed ginglymodian fish (Neopterygii, Semionotiformes) from the Upper Triassic Chinle Formation of southeastern Utah . Journal of Vertebrate Paleontology . 33 . 5 . 1037–1050 . 10.1080/02724634.2013.758125 . 129797885 .
58. Sarah Z. Gibson . 2013 . Biodiversity and Evolutionary History of †Lophionotus (Neopterygii: †Semionotiformes) from the Western United States . Copeia . 2013 . 4 . 582–603 . 10.1643/CI-12-028 . 85755730 . free .
59. Ben T. Kligman . William G. Parker . Adam D. Marsh . 2017 . First record of Saurichthys (Actinopterygii) from the Upper Triassic (Chinle Formation, Norian) of western North America . Journal of Vertebrate Paleontology . 37 . 5 . e1367304 . 10.1080/02724634.2017.1367304 . 134301176 .
60. Listed as "cf. Turseodus" in "Vertebrate Fauna; Osteichthyes; Cf. Turseodus sp." Irmis (2005) p. 66
61. "Vertebrate Fauna; Osteichthyes; Cf. Turseodus sp." Irmis (2005) p. 66
62. Lucas . S.G. . Spencer G. Lucas . Hayden . S.N. . 1989 . Triassic stratigraphy of west-central New Mexico . New Mexico Geological Society Field Conference Guidebook . 40 . 191–211 .
63. Book: Parker, William G. . 2006 . Museum of Northern Arizona . 0-89734-120-1 . Parker . William G. . 62 . 46–64 . The stratigraphic distribution of major fossil localities in Petrified Forest National Park, Arizona . 71015548 . Ash . Sidney R. . Irmis . Randall B. . http://www.miketaylor.org.uk/dino/nm/Parker2006-pefo-biostratigraphy.pdf.
64. Lucas . Spencer G. . 2013 . Plant megafossil biostratigraphy and biochronology, Upper Triassic Chinle Group, Western USA . New Mexico Museum of Natural History and Science Bulletin . 61 . 354–365.
65. Daugherty . Lyman H. . Triassic Roots from the Petrified Forest National Park . 1963 . American Journal of Botany . en . 50 . 8 . 802–805 . 10.1002/j.1537-2197.1963.tb10649.x . 2027.42/141301 . 0002-9122. free .
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67. Frank H. Knowlton. 1889. New species of fossil wood (Araucarioxylon arizonicum) from Arizona and New Mexico. Proceedings of the United States National Museum. 11. 676. 1–5. 10.5479/si.00963801.11-676.1.
68. Ash . Sidney R. . 1987 . The Upper Triassic Red Bed Flora of the Colorado Plateau, Western United States . Journal of the Arizona-Nevada Academy of Science . 22 . 1 . 95–105 . 40024387.
69. Ash . Sidney R. . 1974 . Upper Triassic plants of Canon del Cobre, New Mexico . New Mexico Geological Society Guidebook . 25 . 179–184.
70. Ash . Sidney R. . 1989 . The upper Triassic Chinle flora of the Zuni Mountains, New Mexico . New Mexico Geological Society . 40 . 225–230 . 10.56577/ffc-40.225. 251985942 .
71. Web site: 2006 . Trees to Stone . live . https://web.archive.org/web/20150907234346/http://www.nps.gov/pefo/planyourvisit/upload/TreestoStone2006.pdf . September 7, 2015 . October 3, 2010 . National Park Service.
72. Axsmith . Brian J. . Ash . Sidney R. . 2006 . Two rare fossil cones from the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona, and New Mexico . Museum of Northern Arizona Bulletin . 62 . 82–94.
73. Ash . Sidney R. . 1991 . A New Pinnate Cycad Leaf from the Upper Triassic Chinle Formation of Arizona . Botanical Gazette . 152 . 1 . 123–131 . 10.1086/337871 . 83627771 . 0006-8071.
74. Ash . Sidney R. . 1967 . The Chinle (Upper Triassic) megaflora of the Zuni Mountains, New Mexico . New Mexico Geological Society Fall Field Conference Guidebook . 18 . 125–131 . 10.56577/ffc-18.125. 11630110 .
75. Ash . Sidney R. . 1973 . Two New Late Triassic Plants from the Petrified Forest of Arizona . Journal of Paleontology . 47 . 1 . 46–53 . 1302865.
76. Ash . Sidney R. . Chilbinia Gen. Nov., an Archaic Seed Fern in the Late Triassic Chinle Formation of Arizona, USA . 2006 . Palaeontology . en . 49 . 2 . 237–245 . 10.1111/j.1475-4983.2006.00542.x . 129438630 . 0031-0239.
77. Ash . Sidney R. . 1972 . Late Triassic plants from the Chinle Formation in north-eastern Arizona . Palaeontology . 15 . 4 . 598–618.
78. Ash . Sidney . 1996 . Evidence of arthropod-plant interactions in the Upper Triassic of the southwestern United States . Lethaia . en . 29 . 3 . 237–248 . 10.1111/j.1502-3931.1996.tb01657.x . 0024-1164.
79. Ash . Sidney R. . 2014-06-01 . Contributions to the Upper Triassic Chinle flora in the American southwest . Palaeobiodiversity and Palaeoenvironments . en . 94 . 2 . 279–294 . 10.1007/s12549-014-0150-3 . 129297877 . 1867-1608.
80. Ash . Sidney R. . 1970 . Dinophyton, a problematical new plant genus from the Upper Triassic of the south-western United States . Palaeontology . 13 . 4 . 646–663.
81. Book: Ash, Sidney R. . Brigham Young University Geology Studies . 1978 . 25 . 4: Plant Megafossils . https://www.researchgate.net/publication/292718693.
82. Ash . Sidney R. . 1977 . An unusual bennettitalean leaf from the Upper Triassic of the south-western United States . Palaeontology . 20 . 3 . 641–659.
83. Ash . Sidney R. . 1970 . Pagiophyllum simpsonii, a New Conifer from the Chinle Formation (Upper Triassic) of Arizona . Journal of Paleontology . 44 . 5 . 945–952 . 1302730.
84. Ash . Sidney . Litwin . Ronald J. . 1996 . Two new species of the pinnate microsporophyll Pramelreuthia from the upper Triassic of the southwestern United States . American Journal of Botany . en . 83 . 8 . 1091–1099 . 10.1002/j.1537-2197.1996.tb12807.x.
85. Ash . Sidney R. . Hasiotis . Stephen T. . 2013-04-01 . New occurrences of the controversial Late Triassic plant fossil Sanmiguelia Brown and associated ichnofossils in the Chinle Formation of Arizona and Utah, USA . Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen . 268 . 1 . 65–82 . 10.1127/0077-7749/2013/0316 . 0077-7749.
86. Ash . Sidney R. . 1982 . Occurrence of the Controversial Plant Fossil Sanmiguelia cf. S. lewisi Brown in the Upper Triassic of Utah . Journal of Paleontology . 56 . 3 . 751–754 . 1304404.
87. Ash . Sidney R. . 1968 . A new species of Williamsonia from the Upper Triassic Chinle Formation of New Mexico . Journal of the Linnean Society of London, Botany . en . 61 . 384 . 113–120 . 10.1111/j.1095-8339.1968.tb00108.x.
88. Web site: 2012 . Fossil Trees or Petrified Wood . October 14, 2021 . University of Arizona.
89. Herrick . Alisa S. . Fastovsky . David E. . Hoke . Gregory D. . 1999 . OCCURRENCES OF ZAMITES POWELLII IN OLDEST NORIAN STRATA IN PETRIFIED FOREST NATIONAL PARK, ARIZONA . National Park Service Paleontological Research . 4 . 91–95.
90. Milner . Andrew C. . 2006 . Plant fossils from the Owl Rock or Church Rock members, Chinle Formation, San Juan County, Utah . New Mexico Museum of Natural History & Science Bulletin . 37 . 410–413.
91. Ash . S.R. . 1969 . Ferns from the Chinle Formation (Upper Triassic) in the Fort Wingate area, New Mexico . United States Geological Survey, Professional Paper . Professional Paper . 613-D . 1–40 . 10.3133/pp613d . 2330-7102.
92. Daugherty . Lyman H. . Itopsidema, A New Genus of the Osmundaceae from the Triassic of Arizona . 1960 . American Journal of Botany . en . 47 . 9 . 771–777 . 10.1002/j.1537-2197.1960.tb07164.x.
93. Ash . Sidney . 2000 . Evidence of oribatid mite herbivory in the stem of a Late Triassic tree fern from Arizona . Journal of Paleontology . en . 74 . 6 . 1065–1071 . 10.1666/0022-3360(2000)074<1065:EOOMHI>2.0.CO;2 . 86324641 . 0022-3360.
94. Ash . Sidney . Litwin . Ronald J. . Traverse . Alfred . 1982 . The Upper Triassic fern Phlebopteris smithii (Daugherty) Arnold and its spores . Palynology . en . 6 . 1 . 203–219 . 10.1080/01916122.1982.9989242 . 0191-6122.
95. Ash . Sidney . 1999 . An Upper Triassic Sphenopteris Showing Evidence of Insect Predation from Petrified Forest National Park, Arizona . International Journal of Plant Sciences . en . 160 . 1 . 208–215 . 10.1086/314115 . 85020560 . 1058-5893.
96. Miller . Charles N. . The Lepidophytic Affinities of the Genus Chinlea and Osmundites Walkeri . 1968 . American Journal of Botany . en . 55 . 1 . 109–115 . 10.1002/j.1537-2197.1968.tb06950.x.
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98. Holt . Edward L. . 1947 . Upright Trunks of Neocalamites from the Upper Triassic of Western Colorado . The Journal of Geology . 55 . 6 . 511–513 . 10.1086/625462 . 129374986 . 0022-1376.
99. Miller . Gary L. . Ash . Sidney R. . 1988 . The oldest freshwater decapod crustacean, from the Triassic of Arizona . Palaeontology . 31 . 2 . 273–279.
100. Sidney R. Ash & Geoffrey T. Creber. 2000. The Late Araucarioxylon arizonicum Trees of the Petrified Forest National Park, Arizona, USA. Palaeontology. 43. 22–23. 10.1111/1475-4983.00116. 128691956 . free.