Paleobiota of the Chinle Formation

Crosbysaurus^[1]

C. harrisae^[1]

• Arizona

Utah ^[1]

• Blue Mesa^[1]

A archosauriform represented only by teeth.^[1] It is treated as indeterminate archosauriform remains by Irmis in 2005.^[1] It was originally thought to be an ornithischian dinosaur.

Tanytrachelos^[2]

Indeterminate^[2]

• Arizona^[2]

• Mesa Redondo^[2]

Represented by a cervical rib.^[2]

A tanystropheid represented by several hundred fossil specimens.

Tecovasaurus^[3]

T. murryi^[3]

• Arizona^[3]

• Mesa Redondo^[3]

An unknown amniote represented by scattered teeth formerly believed to be from an ornithischian dinosaur.^[3] Later discoveries of similar teeth in pseudosuchians meant that these could no longer be regarded as anything more specific than some kind of archosauriform.^[3]

Trilophosaurus^[4]

T. buettneri^[5]

• Arizona^[5]

• Blue Mesa^[5]

T. dornorum^[6]

• Arizona^[6]

• Sonsela^[6]

T. jacobsi^[7]

• Arizona^[7]

• Blue Mesa^[7]
• Mesa Redondo^[7]

Vancleavea^[8]

V. campi^[8]

• Arizona^[8]

• Petrified Forest^[8]
• Sonsela^[8]
• Blue Mesa^[8]

A strange aquatic carnivore of uncertain affinities that is represented by both articulated skeletons and scattered elements like osteoderms and vertebrae.^[8]

Acallosuchus^[9]

A. rectori^[9]

• Arizona^[9]

• Blue Mesa^[9]

Known only from a partial skull.^[9]

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.^[9]

Colognathus^[10]

C. obscurus^[10]

• Arizona^[10]

• Blue Mesa^[10]

Known only from a jaw fragment and some isolated teeth.^[10]

Originally believed to be a fish, Colognathus had distinct, fluted teeth.^[10]

Kraterokheirodon^[11]

K. colberti^[11]

• Arizona^[11]

• Petrified Forest^[11]
• Blue Mesa or Mesa Redondo^[11]

Known only from two teeth.^[11]

Although they share some similarities with cynodont teeth, the known Kraterokheirodon teeth are very distinctive and can't be confidently referred to a known amniote group.^[11]

Placerias^[12]

P. hesternus^[12]

• Arizona^[12]

• Blue Mesa^[12]
• Mesa Redondo^[12]

Known from several hundred remains, but very rare outside of the highly concentrated Placerias Quarry.^[12] It was likely uncommon in its ecosystem and the large numbers of specimens in the Placerias Quarry attributable to "taphonomic processes."^[12]

Uatchitodon^[13]

U. schneideri^[14]

• Arizona^[15]

• Mesa Redondo^[15]

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."^[15]

Apachesaurus^[16]

A. gregorii^[16]

• Arizona^[16]

• Owl Rock^[16]
• Petrified Forest^[16]
• Blue Mesa^[16]

Common in the Owl Rock and Petrified forest members.^[16] Blue Mesa remains are fragmentary.^[16]

Koskinonodon^[17]

K. perfecta^[18]

• Arizona^[18]

• Owl Rock^[18]
• Petrified Forest^[18]
• Sonsela^[18]
• Blue Mesa^[18]
• Mesa Redondo^[18]

K. perfecta is "possibly the most common tetrapod fossil in the lower Chinle", although its presence in the upper Chinle is "unclear".^[18]

The new genus Koskinonodon was erected for the species "Buettneria" perfecta when it was discovered that the latter genus was preoccupied.^[17]

Acrodus^[19]

Indeterminate^[19]

• Arizona^[19]

• Petrified Forest^[20]
• Sonsela^[20]
• Mesa Redondo^[19]

Only a single tooth is known.^[19]

Lonchidion^[21]

L. humblei^[21]

• Arizona^[21]

• Blue Mesa^[21]
• Mesa Redondo^[21]

Lonchidion remains are common throughout the Carnian microvertebrate sites of the American southwest.^[21]

Phoebodus^[22]

Indeterminate^[22]

• Arizona^[22]

• Mesa Redondo^[22]

Only a single specimen has been recovered from the formation.^[22]

Reticulodus^[23]

R. synergus^[23]

• Arizona^[23]

• Owl Rock^[23]
• Petrified Forest^[23]
• Sonsela^[23]

The crown of its tooth bears a "reticulating ornamentation on [its] occlusal surface[.]"^[23] Reticulodus remains are common throughout the Norian microvertebrate sites of the American southwest.^[23]

Xenacanthus^[24]

X. moorei^[24]

• Arizona^[24]

• Blue Mesa^[24]
• Mesa Redondo^[24]

Common in the lower Chinle Formation's microvertebrate localities.^[24]

Chinlea^[25]

Indeterminate^[26]

• Arizona^[26]

• Owl Rock^[26]
• Blue Mesa^[26]

Arganodus^[27]

A. dorotheae^[27]

Indeterminate^[27]

• Arizona^[27]

• Petrified Forest^[27]
• Sonsela^[27]
• Blue Mesa^[27]
• Mesa Redondo^[27]

Arganodus toothplates are the most common fossil in the formation from a non-tetrapod.^[27] They are evenly distributed across strata, although some individual localities have very high concentrations.^[27]

Most Chinlean Arganodus fossils are isolated tooth plates.^[27]

Ceratodus^[27]

C. dorotheae^[27]

Named by Case in 1921, in the 1980s it was referred to Arganodus.^[27]

Australosomus^[28]

Indeterminate^[29]

• Arizona^[29]

• Mesa Redondo^[29]

Known only from two vertebrae.^[29]

Lasalichthyes^[30]

Indeterminate^[31]

• Arizona^[31]

• Petrified Forest^[31]
• Blue Mesa^[31]
• Mesa Redondo^[31]

Represented by isolated scales.^[31]

Turseodus^[32]

Indeterminate^[33]

• Arizona^[33]

• Owl Rock^[33]
• Petrified Forest^[33]
• Sonsela^[33]
• Blue Mesa^[33]

Common.^[33]

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.^[33]