Genus: Smilosuchus LONG & MURRY, 1995
Etymology: Etymology; Greek, smil, “chisel” and Greek, souchus, "crocodile."

Species: gregorii (CAMP, 1930) LONG & MURRY, 1995
Etymology:
= Machaeroprosopus gregorii CAMP, 1930
= Nicrosaurus gregorii (CAMP, 1930)
= Phytosaurus gregorii (CAMP, 1930)
= Rutiodon gregorii (CAMP, 1930)

Holotype: UCMP A272/27200

Locality: Round Rock 2 (UCMP A272), Locality 6 miles (9.6 km) southwest of Round Rock Trading Post and 3 miles (3.9 km) southeast of Round Rock, Round Rock Area, Northern Apache County, Arizona.

Horizon: Upper portion of the Lower Chinle Group, estimated to be 300 feet above the base of the Chinle.

Biostratigraphy:

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material: Skull with lower jaws, 8 associated vertebrae, a femur, and 3 dermal scutes.

Referred material:

UCM 48441: Posterior skull roof.

PPM, no number: The complete skull and lower jaws on display as a referred Leptosuchus studeri.

 

Locality: Lower levels of the bentonite beds, Lukachukai W (UCMP A270), Lukachukai Trading Post, 10 km west of Lukachukai, lower level, Lukachukai Area, Petrified Forest, Apache County, Arizona.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27192: Squamosal.

UCMP 27195: Portions of skull, scutes, and limb bones.

 

COLBERT, 1947

Locality: Ward Fossil Locality, about 3 miles east of Cameron, Coconino County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

AMNH No. 3060: Skull and jaws, 6 vertebrae, axis, 3rd, 4th, 5th, and 7th cervicals, 3rd dorsal, cervical rib and fragments of other ribs, left humerus, right ilium, ischium, and pubis, right and left femora, left ilium and ischium, dermal plates probably from the throat region and various other fragments.

 

HECKERT, VINER & CARRANO, 2021

Locality: Blue Hills, St. Johns, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

USNM 18313: Skull and associted incomplte postcranial skeleton.

Note: Pathologic elements; Left humerus, right ulna, left femur and left fibula.

 

KIRBY, 1989

Locality: Ward Terrace, east of the Little Colorado River and west of the Moenkopi Plateau, within an area bounded by Moenkopi Wash to the north and the Tloi Echii Cliffs to the South, Cocconino County, Arizona.

Horizon: Owl Rock Formation, Upper Chinle Group.

Biostratigraphy:

Age: Late Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

MNA V2534: Skull.

 

Locality: Locality MNA 908, Ward Terrace, east of the Little Colorado River and west of the Moenkopi Plateau, within an area bounded by Moenkopi Wash to the north and the Tloi Echii Cliffs to the South, Cocconino County, Arizona.

Horizon: Owl Rock Formation, Upper Chinle Group.

Biostratigraphy:

Age: Late Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

Number: Not given: Temporal fragment of a skull.

 


Locality: Locality MNA 1060, Ward Terrace, east of the Little Colorado River and west of the Moenkopi Plateau, within an area bounded by Moenkopi Wash to the north and the Tloi Echii Cliffs to the South, Cocconino County, Arizona.

Horizon: Owl Rock Formation, Upper Chinle Group.

Biostratigraphy:

Age: Late Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

Number: Not given: Temporal fragment of a skull.

 

LONG & MURRY, 1995

Locality: Nazlini 3 (UCMP V5698), Beautiful Valley, 10 km northwest of Nazlini, Nazlini Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 63921: Very large skull with complete squamosals.

 


Locality: Round Rock 4A, (UCMP V3210), approximately 18 km south of Round Rock Trading Post, Round Rock Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 35737: Very large skull and lower jaws.

 

/CASE & WHITE, 1934

Locality: “Blue Hills” in Sections 5 or 6, Block M 19, C & W Survey, Cerita de la Cruz ("Sweetly Cruz," of local parlance) Creek about 23 miles northwest of Amarillo, Potter County, Texas.

Horizon: Tecovas Member, Dockum Formation.

Biostratigraphy:

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UMMP 14336: Skull.
Note: Referred to Brachysuchus megladon by CASE & WHITE, 1934

 

Locality: Rotten Hill Bonebed (PPHM WT), Herring Ranch Locality, Rotten Hill, Potter County, Texas.

Horizon: Lower part of the Tecovas Formation, Chinle Group (or Tecovas Member, Dockum Formation).

Biostratigraphy:

Age: Adamanian age, Late Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

PPHM WT 3217:L Skull and lower jaws on exhibit (This specimen may represent a skull and lower jaw found approximately 0.8 km apart).

PPHM WT 3214: Huge unprepared skull and lower jaws found in 1952 by Joe Buick on Panhandle Geological Society field trip left by Floyd V. Studer.

?PPHM WT 2920/1: Lower Jaws.

PPHM WT 3220: Distal end of snout of very large individual.

?PPHM WT 3227: Proximal portion of very large left ischium.

? PPHM WT 3228: Proximal portion of very large left pubis.

?PPHM WT 2908: Very large right scapulocoracoid.


LUCAS, HUNT & BENNETT, 1985

Locality: Cosner Ranch, San Jon, Quay County, New Mexico.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

YPM 3695: Median scute.

 


_____________________________________________________________________________________

Species: lithodendrorum (CAMP, 1930) STOCKER, 2010
Etymology:
= Machaeroprosopus lithodendrorum CAMP, 1930
= Rutiodon lithodendrorum (CAMP, 1930)

Holotype: UCMP 26688

Locality: Lithodendron (Carrizo) Creek, 6 miles NW of Adamana, in Navajo County, Arizona.

Horizon: Lower Carrizo Fossil horizon, 346 feet above the base of the Chinle and Shinarump Formations.

Biostratigraphy:

Age: Lowest Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material: Skull with lower jaws, cervical vertebrae, ribs, limb bones and dermal scutes.

Referred material:

UCMP 26683: Fragments of large skull and dermal scutes.

UCMP 26684: Portion of small skull.

UCMP 26719: Skull lacking rostrum.

UCMP 27179: Small skull nearly complete.

UCMP 27181: Juvenile skull complete with vertebrae and scutes.

UCMP 27182: Large broken skull.

 


Locality: Lower Carrizon Horizon, A 258, Petrified Forest, Apache County, Arizona.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP 27151: Large Rostrum.

 

Locality: Second Forest (Crystal Forest), PEFO 085076 (UCMP V7037, MNA 302:93, PF172), Petrified Forest, Apache County, Arizona.

Horizon: Blue Mesa Member, Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Late Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP 26693: Squamosal and section of lower jaws.

UCMP 26694: Small lower jaws.

UCMP ?: Limb bones.

 

Locality: Billings's Gap-7042, Apache County, Arizona.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP 27017: Fragments of skeleton and scutes.

UCMP 27183: Tip of squmosal.

UCMP 27184: Squamosal.

 


Locality: Limestone Reef, PEFO 085135 (UCMP A256, FP58, MNA 302:99), Black Knoll Area, Petrified Forest, Apache County, Arizona.

Horizon: Upper Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Early Norian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP ?: 3 squamosals.

 


Locality: PEFO 085065 (UCMP V7044, MNA 302:94, PF161), First Forest (Jasper Forest), Petrified Forest, Apache County, Arizona.

Horizon: Chinle Formation.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP ?: A symphyseal portion of a pair of lower jaws.

PARKER & NESBITT, 2013

PEFO 34921:

_____________________________________________________________________________________

Species: adamanensis (CAMP, 1930) STOCKER, 2010
Etymology:
= Machaeroprosopus adamanensis CAMP, 1930
= Rutiodon adamanensis (CAMP, 1930)
= Leptosuchus adamanensis (CAMP, 1930)

Holotype: UCMP 26699

Locality: PEFO 085026 (UCMP V85235, MNA 302:115, PF123), Annie’s Canyon (part of V7038), (old Blue Forest, Petrified Forest, 6 miles SE of Adamana), Blue Mesa W Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.
Note: Old Lower Blue Forest fossil horizon 209 feet above the base of the Chinle and Shinarump Formations, Late Triassic.

Material: Skull, dentary, axis, cervical, dorsal, caudal, and sacral vertebrae, scapula and coracoid, ilium, ischia and pubes, dermal scutes.

Referred material:

UCMP 26696: Head of femur.

UCMP 26697: 2 sacral vertebrae.

UCMP 26698: Right dentary and splenial.

UCMP 26706: Pair of small dentaries.

UCMP 26717: Humerus, ventral portions of scapulae, and fragments of skeleton.

UCMP 26718: Large femur.

UCMP 26720: Dorsal scutes.

UCMP 26725: Femur, fragments of vertebrae, ilium and scutes.

UCMP 26727: Vertebra.

UCMP 26729: Vertebrae.

UCMP 26730: Ilium.

UCMP 26731: Vertebrae.

UCMP 26756: Left dentary, anterior part.

UCMP 27093: Dissociated skull elements.

UCMP 27094: Humerus.

UCMP 27104: Very small dentary.

UCMP 27106: Fragments of skull and lower jaws.

AMNH 6813: Skull lacking anterior rostrum.

 


Locality: Camp Butte N1, Dinosaur Wash, Dying Grounds, General Blue Forest Area of C. L. Camp, PEFO 085025 (UCMP V7038, MNA 302:8, SMU 228, PF122), on line between NE 1/4 of NW 1/4 and NW 1.4 of NE 1/, Sec. 26, T 18N, Blue Mesa W Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27099: Small Rostrum.

 

Locality: Phytosaur Basin E, PEFO 085024 (UCMP 7040, MNA 302:101, PF 121), in Blue Mesa siltstone of Self (1965) at very top of siltstone just beneath Camp Butte Sandstone, Blue Mesa W Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27007: Skull deck with both squamosals, portions of lower jaws, several rib sections, much scrap.

UCMP 27008: Skull, ribs, ilia, ischia, vertebrae, femora, tibiae, part of fibula, gastralia and dermal scutes.

UCMP 27010: Fragments of skull and lower jaws.

UCMP ?: Section of lower jaws.

 

Locality: Pictograph Tank, (Locality, 7041), Petrified Forest, Apache County, Arizona.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP 27011: Small crushed skull.

UCMP 27013: Skeletal fragments and teeth.

UCMP 27014: Skeletal fragments and teeth.

UCMP 27015: Skeletal fragments and teeth.

 

 

Locality: Base of Point of Bluff, PEFO 085060 (UCMP 7046, MNA 302:97, USNM 19, PF157),
Petrified Forest, Apache County, Arizona.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UCMP 27025: Series of 13 cervical and dorsal vertebrae.

 


Locality: Base of Point of Bluff, PEFO 085060 (UCMP 7046, MNA 302:97, USNM 19, PF157),
Petrified Forest, Apache County, Arizona.

Horizon: Blue Mesa Member, Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Late Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

USNM 15841: Skull.

 

Locality: Twin Buttes 1, base of Twin Buttes, PEFO 085058 (UCMP 7047, MNA 302:98, PF152), approximately 10 km southwest of Adamana, Twin Buttes Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27026: Large anterior dentary tooth.

UCMP 27027. Distal end of ulna.

 

LONG & MURRY, 1995

Locality: Placerias quarry (UCMP A269, MNA 207C), Big Hollow Wash near Romero Springs, a small valley 6 1/2 miles (approximately 10.4 km) S 65"W of St. Johns, Apache County, Arizona.
Note: Located 0.3 miles northwest of Romero Springs at approximately Long. 109'28'W and lat. 34"27'N on the USGS St. Johns quadrangle of 1921.

Horizon: Bluewater Creek Formation, Lower Chinle Group.

Biostratigraphy:

Age: Adamanian, Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27446: Squamosal.

MNA Pl. 3024, MNA Pl. 3025: Left squamosals.

 

Locality: Downs Quarry (MNA Loc. 207N), approximately 72 m east of Placerias Quarry, Big Hollow Wash near Romero Spring, approximately 10.4 km southwest of St. Johns, Apache County, Arizona.

Horizon: Bluewater Creek Formation, Lower Chinle Group.

Biostratigraphy:

Age: Adamanian, Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

MNA Pl. 2675: A beautifully preserved braincase.
Note: Originally referred to a rauischid by JACOBS & MURRY, 1980, it was found with a number of elements, including a squamosal referable to L. adamanensis.

MNA V3698: Left squamosal.

 

Locality: Fossil Garden, PEFO 085003 (UCMP V82252, PF98) (part of UCMP V7034), 6 to 8 m below? Sonsela Sandstone, Devil’s Playground Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

Number: Not given:

 


Locality: Big Hollow Wash, (UCMP V80003), St. Johns area, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27444, 27185: Two left squamosals.
Note: In 1982, Long and his associates recovered an additional 13 rutiodontine specimens from Camps locality. A number of other fragmentary phytosaur elements have also been recovered from the site. With the exception of the squamosals, these specimens are unassigned to species.

 


Locality: Blue Hills 3 (UCMP 7310), St. Johns, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27060: Miscellaneous fragments including a squamosal referable to L. adamanensis.
Note: Some poposaur material (Poposaurus gracilis) is mixed in with this number.

 


Locality: Battleship W2, PEFO 085073 (UCMP V82264, PF170), Battleship Northwest Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 126991: Right squamosal.

 


Locality: PEFO 085027 (UCMP V85236, MNA 302:116, SMU 230, PF124), Crocodile Hill (part of V7038), in variegated siltstone bed, Blue Mesa W Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 27070: Good skull material representing at lest 3 individuals, some postrcranial elements, number of other specimens listed with same number.

 


Locality: Round Rock 5 (UCMP V6945), 10 km southwest of Round Rock Trading Post, about 3 km northwest of Round Rock, Round Rock Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 124957: Left squamosal.

 

 

Locality: Walker’s Site (PF 82), Devil’s Playground Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

USNM (NPS 72-39, in part): Large beautifully-preserved skull.

 

Locality: Depot Tank E (AMNH EHC 1946:23), Depot Tank Area, Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

AMNH (EHC 1946-23): Fine skull and partial skeleton.

 


Locality: Ward’s Bonebed (UCMP V4121, V4150, V3309, V7317, etc), 5 km northeast to 10 km southeast of Cameron, near Tanner's Crossing, Cameron Area, Petrified Forest, Coconino County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

UCMP 26688: Huge squamosal.

 

LUCAS, OAKES & FROEHLICH 1985

Locality: UNM locality V-601, SW 1/4, SW 1/4, SE 1/4, sec. 28, T9N, R26E, Bull Canyon, Guadalupe County, New Mexico.

Horizon: Chinle Group.

Biostratigraphy:

Age: Carnian Stage, Lower Late Triassic Epoch, Late Triassic.

Material:

UNM V-650: Skull.

 

PARKER & IRIMIS, 2005

Locality: Battleship N locality (PFV 169), Petrified Forest, Apache County, Arizona.

Horizon: Lower Petrified Forest Formation, Chinle Group.

Biostratigraphy:

Age: Latest Carnian Stage, Late Triassic Epoch, Late Triassic.

Material:

PEFO 34043: Fragmentary skull.

 

= Leptosuchus imperfecta CASE, 1922
Etymology:
= Rutiodon imperfecta (CASE, 1922)

Holotype: UMMP 7523

Locality: Spur-Crosbyton Road, west of White River, probably on the Swensen Ranch, Crosby County, Texas.

Horizon: Tecovas Member, Dockum Formation.

Biostratigraphy:

Age: Carnian Stage, Late Triassic Epoch, Late Triassic.

Material: Skull.

 

Composite skeleton (after Long & Murry, 1995). Skull based on Smilosuchus gregorii; vertebral column to anterior caudals of Leptosuchus adamanensis (based on holotypes of Machaeroprosopus adamanensis and M. zunii); girdles based on holotype of Machaeroprosopus adamanensis; mid- and distal portion of tail based largely on the Pseudopalatinae; appendicular elements based on variety of Leptosuchus and pseudopalatine specimens; dermal armor and presacral ribs based on Leptosuchus adamanensis (holotypes of M. zunii and M. adamanensis). Neural spines on caudal vertebrae should probably be inclined more posteriorly an dmanus should probably be reduced in size relative to the pes.