Machaeroprosopus

Machaeroprosopus is an extinct genus of mystriosuchin leptosuchomorph phytosaur from the Late Triassic of the southwestern United States. M. validus, once thought to be the type species of Machaeroprosopus, was named in 1916 on the basis of three complete skulls from Chinle Formation, Arizona. The skulls have been lost since the 1950s, and a line drawing in the original 1916 description is the only visual record of the specimen. Another species, M. andersoni, was named in 1922 from New Mexico, and the species M. adamanensis, M. gregorii, M. lithodendrorum, M. tenuis, and M. zunii were named in 1930. Most species have been reassigned to the genera Smilosuchus, Rutiodon, or Phytosaurus. Until recently, M. validus was considered to be the only species that has not been reassigned. Thus, Machaeroprosopus was considered to be a nomen dubium or "doubtful name" because of the lack of diagnostic specimens that can support its distinction from other phytosaur genera. However, a taxonomic revision of Machaeroprosopus, conducted by Parker et al. in 2013, revealed that UW 3807, the holotype of M. validus, is not the holotype of Machaeroprosopus, while the species Machaeroprosopus buceros, Machaeroprosopus being a replacement name, with a fixed type species, for Metarhinus, is the combinatio nova of the type species of the genu: Belodon buceros. Therefore, the name Pseudopalatus must be considered a junior synonym of Machaeroprosopus, and all species of the former must be reassigned to the latter. This revised taxonomy was already accepted in several studies, including Stocker and Butler (2013). Stocker and Butler (2013) also treated M. andersoni as a valid species, and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).

Machaeroprosopus

Lee Ruk from North Tonawanda · CC BY-SA 2.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.

On record

Recorded, not inferred
Sits inside
MystriosuchiniPBDB
Diet
carnivorePBDB, for Phytosauria
Motility
actively mobilePBDB, for Osteichthyes
Environment
terrestrialPBDB, for Diapsida

Time the record covers

At most 26 million years on record.

Every occurrence read is dated to somewhere between 227.3 Mya and 201.4 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Late Triassic — about 55 of 55 occurrencesLate TriassicEarly Jurassic — about 0 of 55 occurrences228–227 Mya — about 0.7 occurrences227–226 Mya — about 2 occurrences226–225 Mya — about 2 occurrences225–224 Mya — about 2 occurrences224–223 Mya — about 2 occurrences223–222 Mya — about 2 occurrences222–222 Mya — about 2 occurrences222–221 Mya — about 2 occurrences221–220 Mya — about 2 occurrences220–219 Mya — about 2 occurrences219–218 Mya — about 2 occurrences218–217 Mya — about 2 occurrences217–216 Mya — about 2 occurrences216–215 Mya — about 2 occurrences215–214 Mya — about 2 occurrences214–213 Mya — about 2 occurrences213–213 Mya — about 2 occurrences213–212 Mya — about 2 occurrences212–211 Mya — about 2 occurrences211–210 Mya — about 2 occurrences210–209 Mya — about 2 occurrences209–208 Mya — about 2 occurrences208–207 Mya — about 2 occurrences207–206 Mya — about 2 occurrences206–205 Mya — about 2 occurrences205–204 Mya — about 3 occurrences204–204 Mya — about 3 occurrences204–203 Mya — about 3 occurrences203–202 Mya — about 3 occurrences202–201 Mya — about 1 occurrence227.8 Mya200.9 Mya

55 occurrences of Machaeroprosopus on record, most of them in the Late Triassic. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.

When

55 occurrences

These are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.

Found in

8 formations

Chinle — 36.32°N, 106.47°WChinle — 35.03°N, 109.83°WChinle — 35.84°N, 111.25°WChinle — 36.09°N, 111.36°WChinle — 36.07°N, 111.34°WChinle — 35.90°N, 111.29°WChinle — 35.65°N, 111.12°WChinle — 34.86°N, 109.83°WChinle — 34.70°N, 109.58°WChinle — 34.94°N, 109.74°WChinle — 34.83°N, 109.86°WChinle — 35.05°N, 109.73°WChinle — 36.32°N, 106.43°WChinle — 34.83°N, 109.83°WBull Canyon — 35.37°N, 103.38°WBull Canyon — 34.95°N, 104.68°WBull Canyon — 35.16°N, 103.49°WRedonda — 34.98°N, 103.33°WRedonda — 34.94°N, 103.43°WRedonda — 34.97°N, 103.46°WRedonda — 35.00°N, 103.67°WCooper Canyon — 33.11°N, 101.45°WCooper Canyon — 33.45°N, 101.44°WPetrified Forest — 36.21°N, 106.62°WTravesser — 36.94°N, 103.15°WSloan Canyon — 36.92°N, 103.50°WWingate Sandstone — 38.16°N, 109.24°W

Loading coastlines…

The named rock units Machaeroprosopus has been recovered from, largest first. Drawn where the rock is now, not where it formed.

Machaeroprosopus and its relatives

Late Triassic

Where Machaeroprosopus and its relatives were recorded in the Late Triassic.

Found in the same rock

121 taxa

The Paleobiology Database records 42 sites for Machaeroprosopus, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.

This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.

Entered from

24 references

Each of the 55 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. 12 further references are not listed. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content2

Picture of Machaeroprosopus

Credit
Lee Ruk from North Tonawanda
Licence
CC BY-SA 2.0
Commercial use
the licence allows it

Laser scan

Licence
No Copyright (US)
Commercial use
cannot be read from the licence given — check the record
Specimen
Machaeroprosopus pristinus · pefo:382

The description on this site

Licence
CC BY-SA 4.0

This is what the site found, which is not the same as what exists.

Keep going

What may have been alongside itMystriosuchini through timeFormations of the Late TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Mehl 1916