Aguja Formation

 ( Geologic Formations Of Texas ) 

The Aguja Formation is a geological formation in North America, exposed in Texas, United States and Chihuahua and Coahuila in Mexico, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel et al., 2004, "Dinosaur distribution (Late Cretaceous, North America).", pp.574-588 Fossil palms have also been unearthed here.

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Age The ages of the Aguja Formation and its primary fossil-bearing unit, the Alto Shale, are not well understood. Due to the presence of the ammonite Baculites, which only occurs from 80.67 - 80.21 Ma, in the underlying Rattlesnake Mountain Sandstone and the Terlingua Creek Sandstone, it is likely that the Upper Shale was younger than 80.2 Ma. A radiometric date of 76.9 Ma was recovered in the Alto Shale, making it likely the formation wasn't younger than 76.9 Ma. The contact with the overlying Javelina Formation has been estimated at 70 Ma agoWoodward, H. N. (2005). Bone histology of the sauropod dinosaur Alamosaurus sanjuanensis from the Javelina Formation, Big Bend National Park, Texas. but also as recently as 68.5 million years ago.Sankey, J. (2010). Faunal composition and significance of high–diversity, mixed bonebeds containing Agujaceratops mariscalensis and other dinosaurs, Aguja Formation (Upper Cretaceous), Big Bend, Texas. In New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium (pp. 520-537). This is unlikely, however, due to the presence of Bravoceratops, more primitive than an unnamed chasmosaurine from the De-na-zin Member of the Kirtland Formation, in the lowermost section of the formation. The age of the La Basa Sandstone is constrained by the presence of Scaphites hippocrepis III in the overlying Pen Formation which has been dated as old as 81.53 Ma.

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Paleofauna

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Reptiles

2 fragmentary caudal vertebrae of indeterminate are known from the Rattlesnake Mountain sandstone member.

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Ornithischians

Agujaceratops	A. mariscalensis	Texas	Lower Alto Shale		Formerly considered a species of Chasmosaurus
	A. mavericus	West Texas	Middle Alto Shale		A Chasmosaurinae.
Angulomastacator	A. daviesi	Texas	Middle Alto Shale	A left maxilla.	A Lambeosaurinae.
Ankylosauridae	Indeterminate	Texas	Lower Alto Shale	Osteoderms, vertebrae & limb elements.	Remains of an Ankylosauridae, possibly represents Euoplocephalus sp.
AquilarhinusListed as ? Gryposaurus sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.	A. palimentus	Texas	Middle Abajo Shale	Partial skeleton	Formerly referred to Kritosaurus and Gryposaurus.
Ceratopsidae genus & species indeterminate	Indeterminate	West Texas	Middle Abajo Shale	Ilia, sacral vertebra & sacral ribs.	May represent Agujaceratops, but undiagnostic.
Chasmosaurus"Dinosaur distribution (Texas and Chihuahua)." Weishampel, et al. (2004). Page 582 and 588.	C. mariscalensis	Texas		Twelve disarticulated skull (sic), postcrania, juvenile.""Table 23.1," in Weishampel, et al. (2004). Page 496.	Considered by paleontologists Lucas, Sullivan, and Hunt to be distinct enough from the Chasmosaurus type species, C. belli to warrant being split off to a new genus, Agujaceratops.
Edmontonia	E. spListed as Edmontonia cf. rugosidens in "Dinosaur distribution (Late Cretaceous; North America; Texas).", Weishampel et al., 2004, p.582	Texas	Lower Alto Shale	Osteoderm (TVP 45866-2) & skull (AMNH 3076).	A Nodosauridae.
cf. Euoplocephalus	E. sp	Texas	Lower Alto Shale	Osteoderms, sacrum & vertebra (TL-05-14).	An Ankylosauridae.
aff . Kritosaurus	K. navajovius	Texas	Upper Alto Shale	Two dentary teeth	Tooth crown morphology matches with Kritosaurus
Malefica	M. deckerti	Texas	Middle Alto Shale	A partial left maxilla.	Formerly referred to Kritosaurus.
Nodosauridae genus & species indeterminate	Indeterminate	West Texas	Middle Abajo Shale	Isolated & associated osteoderms.	Very similar to osteoderms of Invictarx.
Panoplosaurus	P. mirus	Texas	Lower Alto Shale	Osteoderm (TMM 45605-4).	A Nodosauridae.
Saurolophinae	Indeterminate	Texas	Alto Shale	Various cranial and appendicular elements	Material from several localities previously referred to Kritosaurus but do not have its diagnostic features.
Saurolophinae	Indeterminate	Texas	Alto Shale	Various manual elements and vertebrae representing two individuals	Included in phylogenetic analyses as the "Big Bend OTU", most recently considered a kritosaurin
Stegoceras	S. sp.	West Texas	Middle Alto Shale	Frontal	A pachycephalosaur, represents a new unnamed species
Texacephale	T. langstoni	Texas	Lower Alto Shale	Two frontoparietal domes.	A pachycephalosaur.
Yehuecauhceratops	Y. mudei	Coahuila			A Centrosaurinae.

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Theropods

Indeterminate ornithomimid remains are known from the Upper Aguja Formation. Indeterminate tyrannosaurid fossils are known from the Upper Aguja Formation of Texas and Mexico.

Avialae incertae sedis		West Texas	Middle Abajo Shale	4 teeth (TMM 45947-349, 350, 351).	A bird.
Chirostenotes	C. sp.	Texas		Femur & manual ungual.	A Caenagnathidae
Dromaeosauridae genus & species indeterminate	Indeterminate	West Texas	Middle Abajo Shale	Pedal phalanges (TMM 45909-2, TMM 44066-4).	A Dromaeosauridae.
cf. DromaeosaurusListed as cf. Dromaeosaurus sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.	Indeterminate	Texas"Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.
Leptorhynchos	L. gaddisi	Texas	Lower Alto Shale	Dentaries, caudal vertebra & limb elements.	A caenagnathid
Ornithomimidae	New genus & species	West Texas	Middle Abajo Shale	Vertebrae, ischium & limb elements.	An unnamed species referred to informally as the 'Aguja Ornithomimidae'.
cf. Paronychodon		West Texas	Middle Abajo Shale	2 incomplete teeth (TMM 45947-362).	A .
Richardoestesia	R. cf. gilmorei	Texas	Low Upper Shale	Fragment of a small tooth.	A Coelurosauria.
	R. isosceles	Big Bend National Park, Texas	Low Upper Shale	Teeth.	A Coelurosauria.
Saurornitholestes	S. cf. langstoni	Texas	Lower Alto Shale & Middle Abajo Shale	Teeth.	A Dromaeosauridae.
Saurornitholestinae	Inderteminate	Coahuila		Teeth and Teeth fragment	A Dromaeosauridae.
Theropoda incertae sedis	Morphotype A	West Texas	Alto Shale	8 teeth.	Unserrated, recurved teeth.
	Morphotype B	West Texas		5 tooth crowns.	Bi-serrated teeth.
	Morphotype C	West Texas		7 teeth.	Finely serrated, distal plication only.
	Morphotype D	West Texas		5 teeth.	Short, coarsely serrated distal plication.
	Morphotype E	West Texas		A tooth.	Strongly recurved, serrated distal plication.
	Morphotype F	West Texas		2 tooth fragments.	Medium size, finely serrated plications.
cf. TroodonListed as cf. Troodon sp. in "Dinosaur distribution (Late Cretaceous; North America; Texas)." Weishampel, et al. (2004). Page 582.	Indeterminate	Texas
Tyrannosauridae	Indeterminate	West Texas	Lower Alto Shale & Middle Abajo Shale	Isolated teeth & a handful of non-dental specimens.	Postcranial remains suggest a relatively small & gracile Tyrannosauridae, considered a member of the Teratophoneini

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Sauropods

Indeterminate titanosaurid remains are known from the Upper Aguja Formation of Mexico.Montellano-Ballesteros, M. 2003. "[1]."

Titanosauridae	Indeterminate	Chihuahua		Four partial posterior caudal vertebrae & dorsal or sacrocaudal vertebra	A relatively massive Lithostrotia.

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Crocodylomorphs

Crocodilia	Indeterminate	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Teeth.	A .
Deinosuchus"Aguja Formation (Upper Shale Member), Big Bend Region, Texas," in Sullivan and Lucas (2006). Page 16.	D. riograndensis	Texas, Chihuahua, and Coahuila	Upper Shale	Multiple partial skulls & skeletons accounting for nearly the entire skeleton minus the tail.	A giant Alligatoroidea.
	cf. D. sp.	West Texas	Middle Abajo Shale	Cervical osteoderm (TMM 44068-2).	An Alligatoroidea.
Goniopholididae	New genus & species	West Texas	Middle Abajo Shale	Partial skull & skeleton along with isolated osteoderms & teeth.	May pertain to Denazinosuchus or a related taxon.
Phobosuchus	P. riograndensis	Texas, Chihuahua, and Coahuila			Reclassified as a Deinosuchus species

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Turtles

Adocus	A. sp.	Big Bend National Park, Texas.	Upper Shale	Shell fragments.	An Adocidae.
cf. Aspideretoides		Big Bend National Park, Texas	Upper Shale		A Trionychidae
Baenidae		Big Bend National Park, Texas.	Upper Shale	Shell fragments.	2 morphotypes present (A & B).
Basilemys	B. sp.	Big Bend National Park, Texas.	Upper Shale & Lower Shale	Shell fragments, partial plastron & leg scutes.	A nanhsiungchelyid.
Bothremydidae genus & species indeterminate	Indeterminate	West Texas	Lower Shale	Isolated peripheral bones (TMM 44068-1, 42452-8); costal bones (TMM 44064-6).	A Bothremydidae, compatible with Chupacabrachelys.
Chupacabrachelys	C. complexus	Big Bend, Texas.	Base of the Upper Shale	A complete skull, and a nearly complete skeleton.	A Bothremydidae.
Denazinemys	D. nodosa	West Texas	Lower Shale	Shell elements.	A Baenidae.
cf. Helopanoplia		Big Bend National Park, Texas.	Upper Shale	Shell fragments.	A Trionychidae.
cf. Hoplochelys		Big Bend National Park, Texas.	Upper Shale	Shell fragments.	A Kinosternoidea.
Neurankylus	N. baueri	West Texas	Lower Shale		A Baenidae
Terlinguachelys	T. fischbecki	Big Bend National Park, Texas	Rattlesnake Mountain Sandstone	A large, incomplete specimen.	A Protostegidae.
Thescelus	T. rapiens	West Texas	Lower Shale		A Baenidae
Testudines indeterminate	Morphotype 1	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A shell fragment.
	Morphotype 2	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A shell fragment.
	Morphotype 3	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A shell fragment.
	Morphotype 4	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A shell fragment.
Trionychidae	Gen. et. sp. indet.	Big Bend National Park, Texas.	Upper Shale & Lower Shale	Costal bone (TMM 44068-4) & shell fragments.	A Trionychidae.

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Lepidosaurs

Anguidae	Gen. et. sp. indet.	Texas.		Isolated & partial right Frontal bone.	An Anguidae.
Apsgnathus	A. triptodon	Brewster County, Texas.		Jaw elements.	A Scincomorpha.
Catactegenys	C. solaster	Brewster County, Texas.		Jaw elements & teeth.	A night lizard.
Dryadissector	D. shilleri	West Texas.	Middle Abajo Shale	Numerous isolated teeth.	A Varanoidea.
Mosasauridae	Indeterminate	Ten Bits Ranch.	Rattlesnake Mountain sandstone member.	1 partial vertebra.	A mosasaur.
Odaxosaurus	O. piger	Brewster County, Texas.		Jaw elements.	An Anguidae.
cf. Parasaniwa	cf. P. wyomingensis	Texas.		Jaw fragments.	A .
Platynota	Gen. et. sp. indet.	Texas.		Dorsal vertebra (TMM 43057-332).	A .
?Scincidae	Gen. et. sp. indet.	Brewster County, Texas.		Jaw elements.	A possible skink.
cf. Scincomorpha	Gen. et. sp. indet.	Brewster County, Texas.		Jaw elements.	A Scincomorpha.
Serpentes	Gen. et. sp. indet.	Texas.		Partial left dentary & right maxilla.	A snake.
cf. Xenosauridae		Texas.		& .	A knob-scaled lizard.

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Mammals

Alphadon	A. perexiguus	Brewster County, Texas	Upper Shale		A .
Paleomolops	P. langstoni	Brewster County, Texas	Upper Shale		A ; "cannot be confidently allied with either marsupials or eutherians".

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Bony fish

A diversity of bony fish, comprising both marine (Ten Bits/Rattlesnake Mountain locality) and freshwater (Lowerverse/Lower Shale locality) taxa, is known. Approximately 75 whole and broken fragments of are known from the Rattlesnake Mountain sandstone member, presumably from bony fish.

Acanthomorpha indet.	family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An Acanthomorpha.
Acanthopterygii indet.	order indet. family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An Acanthopterygii.
	Acanthopterygian fin spine morph 1			Fin spines
	Acanthopterygian fin spine morph 2
	Acanthopterygian fin spine morph 3
	Acanthopterygian fin spine morph 4
	Euacanthopterygian fin spine morph 1
	Euacanthopterygian fin spine morph 2
Acronichthys	A. sp.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An Otophysa. Previously considered Ostariophysi indet.
Albula	A. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Over 390 complete and fragmentary teeth.	A Bonefishes.
		Lowerverse, west Texas	Lower Shale
Amiidae indet.	genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An Amiidae.
? Anomoeodus	? A. sp.	Lowerverse, west Texas	Lower Shale	Isolated tooth crown	A Pycnodontiformes. Likely transported out of a marine habitat.
Atractosteus	A. sp.	Lowerverse, west Texas	Lower Shale	Teeth, jaw fragments, vertebral centra, scales.	A gar.
Clupeiformes indet.	family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	A Clupeiformes.
cf. Cyclurus	cf. C. sp.	Lowerverse, west Texas	Lower Shale	5 fragmentary tooth plates with teeth.	An amiid.
Ellimmichthyiformes indet.	family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An ellimmichthyiform.
Elopiformes indet.	family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra	An Elopiformes.
?Enchodus	?E. sp.	Ten Bits ranch, west Texas.	Rattlesnake Mountain sandstone member.	2 abraded teeth.	An Aulopiformes.
		Lowerverse, west Texas	Lower Shale	4 isolated teeth.
Eotexachara	E. malateres	Lowerverse, west Texas	Lower Shale	Dentaries.	A Characiformes.
?Gonorynchiformes indet.	family indet. genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Cranial bone, vertebral centrum, basibranchial.	A gonorynchiform.
Mooneye indet.	genus et sp. indet.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	A Hiodontiformes.
Lepidotes	?L. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Approximately 109 complete and fragmentary teeth.	A Lepidotidae.
cf. Melvius	cf. M. sp.	Lowerverse, west Texas	Lower Shale	Vertebrae, 13 isolated teeth.	An amiid.
Micropycnodon	M. sp.	Lowerverse, west Texas	Lower Shale	4 isolated teeth	A pycnodont. Likely transported out of a marine habitat.
Osteichthyes indet.	Indeterminate species A	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	11 complete teeth.	A Osteichthyes.
	Indeterminate species B			8 complete and fragmentary teeth.
	Indeterminate species C			1 complete tooth.
	Indeterminate species D			1 complete and 1 partial tooth.
	Indeterminate			Approximately 475 complete and fragmentary teleost centra.
	Tooth morph 1	Lowerverse, west Texas	Lower Shale	Teeth
	Tooth morph 2
	Centrum morph 1			Vertebral centra.
	Centrum morph 2
	Centrum morph 3
	Centrum morph 4
Paralbula	P. cf. casei	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Approximately 900 complete and fragmentary teeth and tooth caps.	A bonefish. Lowerverse specimens likely transported out of a marine habitat.
		Lowerverse, west Texas	Lower Shale
Primuluchara	P. laramidensis	Lowerverse, west Texas	Lower Shale	Dentaries.	A Characiformes.
Stephanodus	?S. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	21 whole and fragmentary specimens.	A pycnodont.
? Wilsonichthys	? W. sp.	Lowerverse, west Texas	Lower Shale	Vertebral centra.	An osteoglossiform.

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Cartilaginous fish

Brachyrhyzodus	B. wichitaensis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	11 complete teeth.
Cantioscyllium	C. aff. meyeri	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	1 anterior tooth and 5 lateral teeth.	A Nurse sharks.
Chiloscyllium	C. aff. greeni	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Approximately 90 abraded and fragmentary teeth.	A Bamboo Shark.
Chondrichthyes		Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	23 placoid scales and 69 dermal scales.	4 morphotypes of placoid scales (A to D) present.
Columbusia	C. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	20 complete & fragmentary teeth.	A wobbegong.
Cretalamna	C. appendiculata	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	3 fragmentary teeth.	Reassigned to C. cf. C. sarcoportheta.
	C. cf. C. sarcoportheta	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	3 incomplete teeth & fragments of additional teeth.	Originally reported as C. appendiculata.
Cretorectolobus	C. olsoni	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	"20 complete and fragmentary teeth".	A carpet shark.
Hybodontidae genus & species indeterminate	Indeterminate	West Texas	Lower Shale	Fragment of a dorsal fin spine (TMM 42536-10).	A Hybodontiformes.
Hybodus	H. sp.	Ten Bits Ranch.	Rattlesnake Mountain sandstone member.	2 specimens, one complete and one partial tooth.	A Hybodontiformes.
Igdabatis	I. indicus?	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A single incomplete tooth.	A myliobatid.
Ischyrhiza	I. cf. avonicola	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	5 complete and fragmentary rostral teeth.	A sawskate.
	I. mira	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	11 fragmentary rostral teeth and 230 whole and fragmentary oral teeth.	A sawskate.
Lonchidion	L. conrugis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete and 5 fragmentary teeth.	A Hybodontiformes.
	L. selachos	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete and 5 fragmentary teeth.	A Hybodontiformes.
Meristodon	M. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	2 teeth.	A Hybodontiformes.
Myliobatiformes	Incertae sedis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	3 complete specimens.
Protoplatyrhina	P. renae	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	70 complete and fragmentary teeth.	A Hypsobatidae.
Ptychotrygon	P. agujaensis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Over 690 complete and fragmentary teeth.	A sawskate.
	P. triangularis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Over 170 complete and fragmentary teeth.	A sawskate.
	P. aff. cuspidata	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	7 whole and fragmentary teeth.	A sawskate.
	P. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	One complete tooth (TMM 46018-71).	A sawskate.
Restesia	R. corricki	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete and 5 fragmentary teeth.	A carpet shark.
Rhinobatos	R. casieri	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	"14 complete and fragmentary specimens".	A guitarfish.
	R. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	18 complete & fragmentary specimens.	A guitarfish.
Rhombodus	R. levis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Over 22 complete and fragmentary teeth.	A Rajiformes.
Scapanorhynchus	S. texanus	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	Over 800 complete and fragmentary teeth.	A Mitsukurinidae.
Sclerorhynchidae	Morphotype 1	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	One fragmentary rostral spine (TMM 46018-59).	A sawskate.
	Morphotype 2	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	One fragmentary rostral spine (TMM 46018-60).	A sawskate.
	Morphotype 3	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	3 fragmentary rostral teeth.	A sawskate.
	Morphotype 4	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	27 fragmentary rostral spines.	A sawskate.
Serratolamna	S. cf. S. caraibaea	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	About 34 teeth.	A Mackerel Shark.
Squalicorax	S. kaupi	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	"26 complete and fragmentary anterior and lateral teeth".	An Anacoracidae.
	S. aff. S. lindstromi	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 specimens.	An Anacoracidae.
	S. pristodontus	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	2 specimens.	An Anacoracidae.
	S. aff. S. yangaensis	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete & several fragmentary teeth.	An Anacoracidae.
Squatina	S. hassei	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A single complete specimen.	An angelshark.
	S. sp.	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	A complete tooth & 2 fragmentary teeth.	An angelshark.
Texatrygon	T. cf. T. copei	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete & fragmentary teeth.	A sawskate formerly reported as T. hooveri.
	T. hooveri	Ten Bits Ranch, west Texas.	Rattlesnake Mountain sandstone member.	4 complete and fragmentary specimens.	Reassigned to T. cf. T. copei.

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Invertebrates

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Ammonites

Baculites	B. mclearni		Rattlesnake Mountain Sandstone Terlingua Creek Sandstone
Hoplitoplacenticeras	H. plasticum		Rattlesnake Mountain Sandstone
Pachydiscus	P. paulsoni		Rattlesnake Mountain Sandstone

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Plants

Sabal	S. bigbendense	Big Bend National Park, Texas.	Upper Shale	4 seeds.	A Arecaceae. It has the largest seeds of any fossil Sabal.
	S. bracknellense	Big Bend National Park, Texas.	Upper Shale	5 seeds.	A Arecaceae. The seeds are indistinguishable from those of Eocene S. bracknellense, and so were assigned to that species. However, it is likely these Aguja palms would be found to represent distinct species if other parts of the plants were available for comparison.

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See also

• List of dinosaur-bearing rock formations

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Bibliography

Categories: Geologic Formations Of Texas, Cretaceous Geology Of Texas, Geologic Formations Of Mexico, Cretaceous Mexico, Campanian Stage, Sandstone Formations, Conglomerate Formations Of The United States, Shale Formations, Deltaic Deposits, Lacustrine Deposits, Tidal Deposits, Paleontology In Mexico, Paleontology In Texas, Formations, Conglomerate Formations Of Mexico

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