Placerias Quarry, UCMP A269 (Triassic of the United States)

Where: Apache County, Arizona (34.4° N, 109.5° W: paleocoordinates 10.1° N, 48.1° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Mesa Redondo Member (Chinle Formation), Norian (228.0 - 208.5 Ma)

• One of two nearly adjacent quarries (the second is the Downs Quarry, 30 metres from the Placerias Quarry). Early workers placed the Placerias Quarry low in the Blue Mesa Member, while Lucas et al. (1997) assigned it to the Mesa Redondo (= Bluewater Creek) Member. Parker (2005) noted that the lithology of the beds and the local presence of the Shinarump Member (the basal member of the Chinle Formation) supports the Mesa Redondo assignment. Earliest Adamanian LVF

• group of beds-level stratigraphic resolution

Environment/lithology: wet floodplain; lenticular, brown, red, silty, sandy mudstone and paleosol/pedogenic, concretionary, gray, green, silty, carbonaceous claystone

• "a soft, vegetated pond bottom or other quiet water deposit"; "ancient pond or marsh, an environment of low-energy water flow that may have been seasonally low or dry (as indicated by numerous evaporites." But re-interpreted as a humid-environment soil.
• "The original quarry horizon was a bed of limestone concretions from which many broken or poorly preserved bones were recovered; this gives way to typical reddish-brown Chinle mudstones and silts, with occasional sandstone lenses, in which 'two fossiliferous levels [were] separated by 2 feet of barren sediments'...Calcareous nodules, gypsum lenses, carbonaceous particles, and yellow-brown sulfurous deposits are common"...fossils in "clay-rich mudstone...[that] varies in color from a dark to light olive gray, with little change in mineral composition. These mudstones are dominantly smectite with 10%-25% quartz and traces of feldspar, gypsum, and calcite...'chunks' of this carbonaceous material occur as dark gray and black specks usually less than a millimeter or two in diameter...the calcareous nodules...are autochthonous...[with] a micritic texture." Nodules interpreted as palustrine carbonates.

Size classes: macrofossils, mesofossils, microfossils

Preservation: coprolite

Collected by C. L. Camp in 1931-1934; reposited in the UCMP

Collection methods: bulk, quarrying, mechanical, sieve,

Primary reference: C. L. Camp and S. P. Welles. 1956. Triassic dicynodont reptiles. Part 1. Memoirs of the University of California 13:255-341 [R. Butler/R. Butler/R. Butler]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 39160: authorized by Matthew Carrano, entered by Matthew Carrano on 21.05.2004, edited by Richard Butler, Kaitlin Maguire, Jonathan Tennant and Bethany Allen

Creative Commons license: CC BY (attribution)

Taxonomic list

Chondrichthyes "indet. B"18 Huxley 1880 cartilaginous fish
Chondrichthyes "indet. C"18 Huxley 1880 cartilaginous fish
 Xenacanthiformes - Xenacanthidae
"Xenacanthus moorei" = Triodus moorei18
"Xenacanthus moorei" = Triodus moorei18 Woodward 1889 elasmobranch
 Hybodontiformes - Acrodontidae
Acrodus sp.6 Agassiz 1838 elasmobranch
MNA V3566
 Hybodontiformes - Lonchidiidae
"Lissodus humblei" = Lonchidion humblei12
"Lissodus humblei" = Lonchidion humblei12 Murry 1981 elasmobranch
 Phoebodontiformes - Phoebodontidae
Phoebodus sp.18 St. John and Worthen 1875 elasmobranch
MNA V3500
 Palaeonisciformes - Palaeoniscidae
Gyrolepis sp.18 Agassiz 1843
cf. Turseodus sp.12 Leidy 1857
 Palaeonisciformes - Redfieldiidae
Redfieldiidae indet.18 Hutchinson 1973
Lasalichthyes sp. or Synorichthyes sp.
cf. Cionichthys sp.12 Schaeffer 1967
cf. Lasalichthys sp.12 Schaeffer 1967
 Pholidopleuriformes - Pholidopleuridae
cf. Australosomus sp.1 Pivetau 1930
 Semionotiformes - Semionotidae
Semionotidae indet.18 Woodward 1890
 Dipnoi - Ceratodontidae
Ceratodus sp.12 Agassiz 1838 lungfish
 Coelacanthiformes - Coelacanthidae
Coelacanthidae indet.18 Agassiz 1843 coelacanth
cf. Chinlea sp.1 Schaeffer 1967 coelacanth
 Temnospondyli -
Temnospondyli indet.1 von Zittel 1887 tetrapod
At least 4 morphotypes
 Temnospondyli - Metoposauridae
Apachesaurus gregorii9, "Buettneria perfecta" = Koskinonodon perfectus9
Apachesaurus gregorii9 Hunt 1993 tetrapod
MNA, small centra
"Buettneria perfecta" = Koskinonodon perfectus9 Case 1922 tetrapod
MNA V3039, 3045, unnumbered
 Procolophonia - Procolophonidae
Procolophonidae indet.9 Lydekker 1889 parareptile
 Eosuchia -
Trilophosaurus sp.9 Case 1928 archosauromorph
UCMP 32390, 25877, 25825, 25839, 25826, 25798, 25790, 25424, MNA V2924, 2956, 2928. Postcrania
Trilophosaurus jacobsi n. sp.11 Murry 1987 archosauromorph
MNA V3192 (holotype), 3193, 3198, 3199, mandibular fragments. MNA V3194, 3197, maxillary fragments
Archosauriformes indet.6 Gauthier 1986 archosauromorph
Uatchitodon schneideri10 Mitchell et al. 2010 archosauromorph
MNA V3680, tooth
 Eosuchia - Doswelliidae
Vancleavea campi15 Long and Murry 1995 archosauromorph
MNA V 3669, V3670, UCMP 152646, vertebrae
 Eosuchia - Proterochampsidae
Proterochampsidae indet.1 Romer 1966 archosauromorph
 Archosauria -
Archosauria indet.5 Cope 1869 archosaur
 Dinosauromorpha - Lagerpetonidae
Dromomeron gregorii14 Nesbitt et al. 2009 ornithodiran
UCMP 25815
 Dinosauromorpha -
Dinosauriformes indet.13 Novas 1992 ornithodiran
UCMP 25834, distal femur
Dinosauriformes indet.6 Novas 1992 ornithodiran
UCMP 25793, distal tibia
Camposaurus arizonensis n. gen. n. sp.5
Camposaurus arizonensis n. gen. n. sp.5 Hunt et al. 1998 dinosaur
 Saurischia -
Saurischia indet.6 saurischian
UCMP 139622, femur. UCMP 25820, distal tibia
 Theropoda -
Theropoda indet.13 theropod
UCMP 25830
 Saurischia - Herrerasauridae
Herrerasauridae indet.5 Benedetto 1973 herrerasaurid
UCMP, 5 dorsal centra
 Ornithischia -
Ornithischia indet.1 ornithischian
 Pterosauria -
? Pterosauria indet.9 Kaup 1834 pterosaur
Parrishia mccreai n. gen. n. sp.9
Parrishia mccreai n. gen. n. sp.9 Long and Murry 1995 archosaur
UCMP 139623 (holotype), cervical. Referred vertebrae
 Pseudosuchia - Shuvosauridae
"Chatterjeea elegans" = Shuvosaurus inexpectatus9
"Chatterjeea elegans" = Shuvosaurus inexpectatus9 Chatterjee 1993 archosaur
MNA V3743, femur
 Stagonolepididae - Stagonolepididae
Acaenasuchus geoffreyi9 Long and Murry 1995 archosaur
MNA V3668, Pl. 3040, Pl. 3043, V3679, Pl. 2921, Pl. 2952, Pl. 3002, Pl. 3007, Pl. 3046, all plates
Desmatosuchus spurensis16 Case 1920 archosaur
UCMP collections. See Long & Murry (1995) for full specimen list
"Stagonolepis wellesi" = Calyptosuchus wellesi9 Long and Ballew 1985 archosaur
UCMP collections. See Long & Murry (1995) for full specimen list
? Tecovasuchus sp.3 Martz and Small 2006 archosaur
UCMP A269/126847, A269/136744
Tecovasuchus chatterjeei3 Martz and Small 2006 archosaur
MNA 2898, osteoderm
 Aetosauria -
Revueltosaurus hunti2 Heckert 2002 archosaur
MNA V3195, 3200, teeth previously referred to Trilophosaurus jacobsi
 Loricata -
Sphenosuchia indet.1 crocodilian
"Large sphenosuchian"
Hesperosuchus agilis1 Colbert 1952 crocodilian
 Loricata - Rauisuchidae
Postosuchus kirkpatricki9 Chatterjee 1985 rauisuchid
UCMP A269/27492, 27572, 27441, 140035, 124586, 27481, 27440, 27478, 27447, 27449, 27450, 27485, cranial material
 Pseudosuchia -
Poposaurus gracilis9 Mehl 1915 archosaur
UCMP & MNA collections. See Long & Murry (1995) for full specimen list
 Phytosauria - Parasuchidae
Rutiodon sp.1, Leptosuchus sp.9, "Leptosuchus adamanensis" = Smilosuchus adamanensis9
Rutiodon sp.1 Emmons 1856 archosaur
Leptosuchus sp.9 Case 1922 archosaur
Numerus specimens - see Long & Murry (1995) for details
"Leptosuchus adamanensis" = Smilosuchus adamanensis9 Camp 1930 archosaur
UCMP 27446, MNA V3024, 3025, squamosals
 Phytosauria -
"Parasuchia indet." = Phytosauria6
"Parasuchia indet." = Phytosauria6 Jaeger 1828 archosaur
 Eosuchia -
Tecovasaurus murryi4 Hunt and Lucas 1994 archosauromorph
MNA V1699, 1704, teeth
 Eosuchia - Tanystropheidae
Tanytrachelos sp.7 Olsen 1979 archosauromorph
Cervical rib
 Eosuchia -
Lepidosauromorpha indet.1 Benton 1983 crown diapsid
 Rhynchocephalia - Sphenodontidae
Sphenodontidae indet.11 Cope 1869 rhynchocephalian
MNA V3190, 3191, 3605-3612
 Eosuchia - Kuehneosauridae
? Kuehneosauridae indet.1 Romer 1966 crown diapsid
 Diapsida - Drepanosauridae
Drepanosauridae indet.17 Berman and Reisz 1992 diapsid
MNA V3637, posterior caudal vertebra. MNA V3652 (in part), posterior cervical vertebra, centrum
cf. Drepanosauridae indet.17 Berman and Reisz 1992 diapsid
MNA V3652 (in part), neural arch
 Diapsida -
Palacrodon sp.8 Broom 1906 diapsid
MNA V3684, jaw fragment; V11247, tooth
 Therapsida - Cynodontia
Cynodontia indet.7 therapsid
MNA V3618-3625, 3563
 Therapsida - Stahleckeriidae
"Placerias gigas n. sp." = Placerias hesternus
"Placerias gigas n. sp." = Placerias hesternus Lucas 1904 dicynodont