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Showing results for tags 'premaxillary'.
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Hello, Could I get an ID for this little premaxillary/nasal jaw piece? It's from the Permian-aged Ryan Formation near Waurika, Oklahoma, USA. It measures a little over 1 cm including the tooth, and seems to be from the right maxilla. I believe it contains the anterior border of the nasal opening. The seller says it could be from a Secodontasaurus or undescribed reptile.
- 17 replies
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- permian
- premaxillary
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This is being sold as a Spinosaurus premaxillary jaw from the Kem Kem, but I'm suspicious. Any opinions? And if not Spinosaurus, what could it be? Size 23 cm / 9.06 inch
- 4 replies
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- spinosaurus
- premaxillary
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Hi all, Do you agree that this 0,7 inch tooth from the Hell Creek formation is a tyrannosaurid premax, or could it be something else? Thanks!
- 6 replies
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- hell creek fm
- tyrannosaurid
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"That some of these teeth are mammalian incisors there can be but little doubt..." - O. C. Marsh1 This kind of incisor-like ("incisiform") tooth was originally thought to have belonged to a large, Cretaceous mammal. Later discoveries revealed that these teeth were actually the front teeth ("premaxillary teeth") of Tyrannosaurs - and are now known as a hallmark of their clade, Tyrannosauroidea (along with fused nasals). Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to selectively scrape meat from bone2. Identification Tyrannosaurid premaxillary teeth have a "D"-shaped cross section, with the lingual face flattened, and often have an apicobasal ridge on the midline of the lingual face. In more technical language, "...premaxillary teeth bear lingually rotated mesial and distal carinae forming a salinon cross-section at mid-crown height, and a highly convex labial aspect as in tyrannosauroids generally. In mesial/distal views carinae are sinuous, transitioning from lingually convex near the base to lingually concave approaching the occlusal surface. Carinae terminate prior to reaching the root/crown juncture. Mesial and distal aspects of the crown are depressed, yielding a weakly hourglass-shaped cross-section at the crown base... The carinae lack serrations [likely ontogenetically variable]... As in other tyrannosauroids, teeth exhibit a pronounced lingual ridge"3. Most of the current literature supports only one Tyrannosaurid species in the Hell Creek formation, Tyrannosaurus rex, a hypothesis subject to change in light of new evidence. Comments This tooth has no discernible antemortem wear. The collector appears to have applied some preservative coating, giving the enamel a slightly sharper gloss. Given the size, this is from a very young animal (smaller than "Jane", BMRP 2002.4.1). References 1. Marsh, O.C., 1892, "Notes on Mesozoic vertebrate fossils", American Journal of Science, 44: 170-176 2. David W.E. Hone and Mahito Watabe, "New information on scavenging and selective feeding behaviour of tyrannosaurs", Acta Palaeontologica Polonica 55 (4), 2010: 627-634 doi: http://dx.doi.org/10.4202/app.2009.0133 3. Zanno, L., Tucker, R.T., Canoville, A. et al. Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record. Commun Biol 2, 64 (2019). https://doi.org/10.1038/s42003-019-0308-7
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- tyrannosaurid
- tyrannosauridae
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"That some of these teeth are mammalian incisors there can be but little doubt..." - O. C. Marsh1 This kind of incisor-like ("incisiform") tooth was originally thought to have belonged to a large, Cretaceous mammal. Later discoveries revealed that these teeth were actually the front teeth ("premaxillary teeth") of Tyrannosaurs - and are now known as a hallmark of their clade, Tyrannosauroidea (along with fused nasals). Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to selectively scrape meat from bone2. Identification Tyrannosaurid premaxillary teeth have a "D"-shaped cross section, with the lingual face flattened, and often have an apicobasal ridge on the midline of the lingual face. In more technical language, "...premaxillary teeth bear lingually rotated mesial and distal carinae forming a salinon cross-section at mid-crown height, and a highly convex labial aspect as in tyrannosauroids generally. In mesial/distal views carinae are sinuous, transitioning from lingually convex near the base to lingually concave approaching the occlusal surface. Carinae terminate prior to reaching the root/crown juncture. Mesial and distal aspects of the crown are depressed, yielding a weakly hourglass-shaped cross-section at the crown base... The carinae lack serrations [likely ontogenetically variable]... As in other tyrannosauroids, teeth exhibit a pronounced lingual ridge"3. Most of the current literature supports only one Tyrannosaurid species in the Hell Creek formation, Tyrannosaurus rex, a hypothesis subject to change in light of new evidence. Comments This tooth exhibits some antemortem wear at the apex (pictured), on the carinae, and near the base of the lingual apicobasal ridge. Given the size, this is from a juvenile animal (smaller than "Jane", BMRP 2002.4.1). References 1. Marsh, O.C., 1892, "Notes on Mesozoic vertebrate fossils", American Journal of Science, 44: 170-176 2. David W.E. Hone and Mahito Watabe, "New information on scavenging and selective feeding behaviour of tyrannosaurs", Acta Palaeontologica Polonica 55 (4), 2010: 627-634 doi: http://dx.doi.org/10.4202/app.2009.0133 3. Zanno, L., Tucker, R.T., Canoville, A. et al. Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record. Commun Biol 2, 64 (2019). https://doi.org/10.1038/s42003-019-0308-7
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- tyrannosaurid
- tyrannosauridae
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From the album: Hell Creek / Lance Formations
This kind of incisor-like ("incisorform") tooth was originally thought to have belonged to a large, Cretaceous mammal. Later discoveries revealed that these teeth were actually the front teeth ("premaxillary teeth") of Tyrannosaurs - and are now known as a hallmark of their clade, Tyrannosauroidea. Closely-spaced, parallel grooves on bones suggest that Tyrannosaurs used these teeth to scrape meat from bone. Given the size, this is from a juvenile animal (smaller than "Jane"). Should Nanotyrannus be valid, then this should be considered an indeterminate Tyrannosaurid.-
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- lancian
- hell creek
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From the album: Dinosaurs
These strange, incisor-like teeth were originally thought to have belonged to a large Cretaceous mammal. Later discoveries showed that these teeth matched the front teeth of young Tyrannosaurs quite well. Given closely spaced, parallel feeding traces on bones, these "incisorform" teeth likely were used to scrape meat from bone.-
- dinosaur tooth
- cretaceous
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From the album: Marine reptiles and mammals
View of the underside with teeth-
- mosasaur
- premaxillary
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From the album: Marine reptiles and mammals
2 unidentified mosasaur species' anterior end of premaxillary bones. One with teeth broken off just beyond the skull, and the other has 2 remaining teeth, with the rest broken off at the level of the skull. the larger fossil was found in the phosphate mines of Khouribga, Morocco. ive since lost the information for the smaller fossil, sadly.-
- mosasaur
- premaxillary
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