[D] Ricardoestesia isosceles
Describer
Sankey, 2001
Time
Cretaceous Late Campanian Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria
Diet
Carnivore
Fossilsite
Aguja Formation, Big Bend National Park, Texas; Lance Formation, Wyoming; Hell Creek Formation, North Dakota - South Dakota, US; Horseshoe Canyon Formation, Oldman Formation, Milk River Formation, Dinosaur Park Formation = Judith River Wedge, Alberta, Canada; Ocozocoautla Formation, Chiapas, Mexico
Fall Under
Ricardoestesia
Info
Ricardoestesia (Currie, Rigby & Sloan, 1990) > Ricardoestesia gilmorei (Currie, Rigby & Sloan, 1990) > Ricardoestesia isosceles (Sankey, 2001)
Holotype
LSUMG 489:6238, tooth
Comments by Mickey Mortimer
Etymology
\\\\\\\"Richard Estes\\\\\\\' isosceles triangle\\\\\\\", after the famous paleontologist Richard Estes, who demonstrated the use of theropod teeth in faunal studies.
Other material
(LSUMG 488:5483) tooth (FABL 9 mm) (LSUMG 489:6239) tooth (FABL 5.5 mm)
Description
These tooth fragments are not assignable to any known genus of Judithian theropod. They are slightly flattened, recurved and serrated (3.5-5.5 per mm). The serrations are slightly rounded with narrow interdenticle spaces.
This species was originally suggested by Currie, Rigby and Sloan to account for the stright Ricardoestesia teeth in some collections.
The teeth are similar to Ricardoestesia gilmorei in most respects. They are laterally compressed with serrations present posteriorly and sometimes anteriorly. The serrations are small (7-11 per mm), flattened, uniform in size and have small interdenticle spaces. The only difference is the straight crown with the tip roughly in the center. Ricardoestesia gilmorei teeth are recurved, as is usual for theropods.
Relationships
Ricardoestesia can be diagnosed by- teeth with very small serrations for size; distal half is convex posteriorly on anterior dentary teeth. The phylogenetic relationships of Ricardoestesia are obscure due to the many plesiomorphies, although it can be safely omitted from several groups (Ornithomimosauria, [Segnosauria] + Oviraptorosauria, Alvarezsauridae, Troodontidae, [Eumaniraptora]).
Perhaps it is related to basal coelurosaurs, tyrannosaurs or Bagaraatan. A proper assessment of Ricardoestesia\\\\\\\'s relationships would focus on the better known Ricardoestesia gilmorei, so will not be considered further here. Sankey finds these teeth are very similar to Dromaeosaurus, except they lack the lingually twisted anterior carinae autapomorphic of that genus (and seen in cf. Dromaeosaurus teeth from the Kimmeridgian of Portugal). Perhaps this is a distinct dromaeosaurine genus.
Report on Richardoestesia isosceles from Chiapas, southern Mexico: Carbot-Chanona, G. & Rivera-Sylva, H.E. (2011)
Holotype
IHNFG-0537, isolated maxilar tooth.
Description
Small tooth, triangular in shape, with the mesial border slightly curved; labio-lingually flattened oval in cross section. Small denticles present on mesial and distal carinae. The mesial denticles are much more distinct than the distal, and generally 7 to 9 denticles per millimeter are present; denticles are 0.13-0.17 mm wide and 0.13-0.2 mm high. The denticles are approximately uniform in size from halfway to the tip of tooth, but are not observed near the base. The denticles are nearly square, with rounded outline
Sankey, 2001
Time
Cretaceous Late Campanian Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria
Diet
Carnivore
Fossilsite
Aguja Formation, Big Bend National Park, Texas; Lance Formation, Wyoming; Hell Creek Formation, North Dakota - South Dakota, US; Horseshoe Canyon Formation, Oldman Formation, Milk River Formation, Dinosaur Park Formation = Judith River Wedge, Alberta, Canada; Ocozocoautla Formation, Chiapas, Mexico
Fall Under
Ricardoestesia
Info
Ricardoestesia (Currie, Rigby & Sloan, 1990) > Ricardoestesia gilmorei (Currie, Rigby & Sloan, 1990) > Ricardoestesia isosceles (Sankey, 2001)
Holotype
LSUMG 489:6238, tooth
Comments by Mickey Mortimer
Etymology
\\\\\\\"Richard Estes\\\\\\\' isosceles triangle\\\\\\\", after the famous paleontologist Richard Estes, who demonstrated the use of theropod teeth in faunal studies.
Other material
(LSUMG 488:5483) tooth (FABL 9 mm) (LSUMG 489:6239) tooth (FABL 5.5 mm)
Description
These tooth fragments are not assignable to any known genus of Judithian theropod. They are slightly flattened, recurved and serrated (3.5-5.5 per mm). The serrations are slightly rounded with narrow interdenticle spaces.
This species was originally suggested by Currie, Rigby and Sloan to account for the stright Ricardoestesia teeth in some collections.
The teeth are similar to Ricardoestesia gilmorei in most respects. They are laterally compressed with serrations present posteriorly and sometimes anteriorly. The serrations are small (7-11 per mm), flattened, uniform in size and have small interdenticle spaces. The only difference is the straight crown with the tip roughly in the center. Ricardoestesia gilmorei teeth are recurved, as is usual for theropods.
Relationships
Ricardoestesia can be diagnosed by- teeth with very small serrations for size; distal half is convex posteriorly on anterior dentary teeth. The phylogenetic relationships of Ricardoestesia are obscure due to the many plesiomorphies, although it can be safely omitted from several groups (Ornithomimosauria, [Segnosauria] + Oviraptorosauria, Alvarezsauridae, Troodontidae, [Eumaniraptora]).
Perhaps it is related to basal coelurosaurs, tyrannosaurs or Bagaraatan. A proper assessment of Ricardoestesia\\\\\\\'s relationships would focus on the better known Ricardoestesia gilmorei, so will not be considered further here. Sankey finds these teeth are very similar to Dromaeosaurus, except they lack the lingually twisted anterior carinae autapomorphic of that genus (and seen in cf. Dromaeosaurus teeth from the Kimmeridgian of Portugal). Perhaps this is a distinct dromaeosaurine genus.
Report on Richardoestesia isosceles from Chiapas, southern Mexico: Carbot-Chanona, G. & Rivera-Sylva, H.E. (2011)
Holotype
IHNFG-0537, isolated maxilar tooth.
Description
Small tooth, triangular in shape, with the mesial border slightly curved; labio-lingually flattened oval in cross section. Small denticles present on mesial and distal carinae. The mesial denticles are much more distinct than the distal, and generally 7 to 9 denticles per millimeter are present; denticles are 0.13-0.17 mm wide and 0.13-0.2 mm high. The denticles are approximately uniform in size from halfway to the tip of tooth, but are not observed near the base. The denticles are nearly square, with rounded outline