TABLE 1. Comparison of tooth enamel thickness and enamel microstructural features in different archosauromorphs compiled from the literature.
Tooth Enamel Microstructure
Higher Taxon | Taxon | Sampler | minimum thickness |
maximum thickness |
Parallel | Columnar | BUL | LIG | Wavy | Tubules | Comments |
Archosauromorpha |
Trilophosaurus |
Sander (1999) |
20 |
20 |
|
|
x |
x |
|
|
|
Crurotarsi |
Phytosauridae (Dockum) |
Sander (1999) |
20 |
20 |
x |
|
|
x |
|
|
I and III |
|
Phytosauridae (Dockum) |
Sander (1999) |
|
150 |
x |
x |
x |
x |
|
|
II |
|
Phytosauridae (Hallau) |
Sander (1999) |
|
60 |
|
x |
|
|
|
|
|
|
Rauisuchidae |
Sander (1999) |
60 |
100 |
x |
x |
x |
x |
|
|
95% columnar; outer is parallel; rare LIG |
Mesosuchia |
Machimosaurus hugi |
Sander (1999) |
|
350 |
x |
x |
x |
|
|
|
LIG rare |
Crocodylia: Alligatoridae |
Allognathosuchus sp. |
Sander (1999) |
|
300 |
x |
x |
|
x |
|
|
up to 50/50 columnar/parallel; sometimes 95/5; LIG only in parallel |
|
Alligator mississippiensis |
Sander (1999) |
|
1000 |
x |
x |
x |
x |
|
|
Mostly columnar; LIG in columnar enamel |
Crocodylia: Crocodylidae |
Deinosuchus riograndensis |
Sander (1999) |
<150 |
525 |
|
x |
x |
|
|
|
40% columnar; 55% microunit; only specimen w/described microunits |
|
Asiatosuchus |
Sander (1999) |
|
500 |
|
x |
x |
|
|
|
compound unit enamel/weakly columnar |
|
Pristichampsa |
Sander (1999) |
20 |
50 |
x |
x |
|
x |
|
|
LIG best in the carinae |
|
Eusuchia indet |
Sander (1999) |
50 |
125 |
x |
x |
|
x |
|
|
Columnar yields to parallel |
Dinosauria:Saurischia: Theropoda |
|||||||||||
|
Basal Theropoda indet. |
Hwang (2009) |
|
|
x |
x |
x |
|
|
x |
100 µm average thickness; Kayenta Fm "carnosaur" in UCMP collections |
D:S:T:Ceratosauria |
Coelophysis bauri |
Hwang (2005, 2011) |
10 |
10 |
x |
|
|
x |
|
|
C. bauri of Hwang (2005) a distinct taxon (Hwang, 2011, p. 192) |
|
Ceratosaurus nasicornis |
Hwang (2011) |
20 |
70 |
x |
x |
x |
x |
|
x |
120 µm average thickness; varies wildly |
|
Majungasaurus sp. |
Hwang (2011) |
<50 |
>90 |
x |
x |
x |
x |
|
x |
|
D:S:T:Allosauroidea |
Allosaurus fragilis |
Hwang (2011) |
20 |
>85 |
x |
x |
x |
x |
|
|
|
|
cf. Allosaurus |
Sander (1999) |
10 |
15 |
x |
|
|
|
|
|
Not even LIG |
|
Charcharodontosaurus |
Buffetaut et al. (1986) |
|
|
|
x |
|
|
|
|
called "prisms" in published description |
|
Spinosaurus |
Buffetaut et al. (1986) |
|
|
|
x |
|
|
|
|
called "prisms" in published description |
|
"Carnosaur" |
Buffetaut et al. (1986) |
|
|
x |
? |
x |
|
|
|
|
D:S:T: Coelurosauria |
|
|
|
|
|
x |
|
|
|
|
|
D:S:T:C: Tyrannosauridae |
Tyrannosauridae indet. (TX) |
Sander (1999) |
150 |
200 |
x |
x |
|
|
|
|
Thickest at base of carina; parallel only at the outer edge, great columnar |
|
Tyrannosauridae indet. (MT) |
Sander (1999) |
|
120 |
x |
x |
x |
|
|
|
|
|
Tyrannosauridae indet. |
Hwang (2005, 2009) |
|
|
x |
x |
x |
|
|
x |
115 µm average thickness |
|
Tyrannosauridae indet. (="Nanotyrannus") |
Hwang (2009) |
|
|
x |
x |
|
|
|
x |
60µm average thickness; juvenile tyrannosaurid assigned to "Nanotyrannus" in UWGM collections |
|
Daspletosaurus torosus |
Hwang (2011) |
|
|
|
x |
|
x |
|
x |
80 µm average thickness |
|
cf. Gorgosaurus sp. |
Hwang (2009) |
|
|
x |
x |
x |
|
|
x |
80 µm average thickness |
|
Gorgosaurus libratus |
Hwang (2011) |
|
|
x |
x |
x |
x |
|
x |
|
|
Albertosaurus sarcophagus |
Hwang (2005) |
60 |
180 |
x |
x |
|
|
|
|
|
|
Albertosaurus sp. |
Stokosa (2005) |
100 |
120 |
x |
x |
|
|
|
x |
|
|
?Albertosaurus gen. A. indet. |
Stokosa (2005) |
40 |
55 |
x |
x |
|
x |
|
|
SDSM 12737; tip of tooth |
|
?Albertosaurus gen. A. indet. |
Stokosa (2005) |
180 |
200 |
x |
x |
|
x |
|
|
SDSM 15143 |
|
?Albertosaurus gen. A. indet. |
Stokosa (2005) |
95 |
100 |
x |
x |
|
x |
|
|
SDSM 64351 |
|
Tyrannosaurus sp. |
Hwang (2011) |
|
|
|
x |
|
|
|
x |
200 µm average thickness |
|
cf. Tyrannosaurus rex |
Stokosa (2005) |
45 |
50 |
x |
x |
|
x |
|
x |
SDSM 15135; Poorly developed columnar |
|
cf. Tyrannosaurus rex |
Stokosa (2005) |
60 |
75 |
|
|
|
|
|
|
SDSM 64287 |
|
cf. Tyrannosaurus rex |
Stokosa (2005) |
80 |
90 |
|
|
|
|
|
|
SDSM 15115 |
|
Tarbosaurus |
Dauphin et al. (1989) |
|
|
|
x |
|
|
|
|
intrepreted from pl. 2, fig. 4 |
|
Tarbosaurus |
Hwang (2005) |
|
300 |
x |
x |
|
|
|
|
|
D:S:T:C:incertae sedis |
Richardoestesia cf. R. gilmorei |
Stokosa (2005) |
10 |
10 |
x |
|
|
|
|
|
|
|
Richardoestesia gilmorei |
Hwang (2011) |
~10 |
~10 |
x |
|
x |
x |
|
x |
10 µm average thickness |
|
Richardoestesia isosceles |
Hwang (2011) |
~13 |
~13 |
x |
|
x |
|
|
x |
13 µm average thickness |
|
Richardoestesia sp. |
Stokosa (2005) |
10 |
15 |
x |
|
|
|
|
|
|
D:S:T:C:Maniraptora |
Troodontid indet. A |
Hwang (2005) |
|
60 |
x |
|
|
|
|
|
|
|
Troodontid indet. B |
Hwang (2005) |
|
|
x |
x |
|
|
|
|
|
|
Troodontid n. gen. et. Sp. |
Hwang (2005) |
|
30 |
x |
|
|
x |
|
|
|
|
Troodon sp. |
Sander (1999) |
|
20 |
x |
x |
x |
|
|
|
Columnar units small (2µm) and weak, seem to arise from BUL (Sander, p. 65) |
|
Troodon sp. |
Hwang (2009, 2011) |
|
|
x |
|
x |
|
|
|
20µm average thickness; parallel crystallites |
|
Troodon sp. cf. T. formosus |
Stokosa (2005) |
10 |
15 |
x |
|
|
|
|
|
|
|
Paronychodon cf. P. lacustris |
Stokosa (2005) |
0 |
15 |
x |
|
|
|
|
|
|
|
Paronychodon lacustris |
Sander (1999) |
|
20 |
x |
|
|
x |
|
|
LIG are few and weak |
|
Paronychodon (Troodontid) |
Hwang (2005) |
|
|
x |
|
|
x |
|
|
|
|
Byronosaurus jaffei |
Hwang (2005) |
|
13 |
x |
|
|
x |
|
|
|
|
Paronychodon (Dromaeosaurid) |
Hwang (2005) |
|
|
|
|
|
|
|
|
|
|
Velociraptor |
Dauphin et al. (1989) |
|
|
x |
|
|
|
|
|
interpreted from pl. 1, figs. 4-5 |
|
Velociraptor mongoliensis |
Hwang (2005) |
|
24 |
x |
|
x |
|
|
|
|
|
Bambiraptor feinbergi |
Hwang (2005) |
|
|
x |
|
|
x? |
|
|
No LIG in Hwang (2005), but faint in Hwang (writ. Comm.) |
|
Dromaeosauridae indet. |
Hwang (2005) |
|
55 |
x |
|
x |
|
|
|
|
|
Deinonychus antirrhopus |
Hwang (2011) |
17 |
30+ |
x |
|
x |
x |
|
x |
BUL poorly developed; LIG faint |
|
Saurornitholestes sp. |
Hwang (2011) |
7 |
20+ |
x |
|
x |
|
|
x |
BUL half of enamel thickness |
|
Dromaemosaurus sp. |
Hwang (2011) |
25 |
35 |
x |
|
x |
x |
|
x |
BUL half of enamel thickness, but not well-developed |
|
Dromaeosaurus sp. cf. D. albertensis |
Stokosa (2005) |
40 |
45 |
x |
x |
|
x |
|
|
Columnar at EDJ, divergent parallel more at OES |
D:S:T:Avialae |
Indeterminate Avialan A |
Hwang (2011) |
|
|
x |
|
x |
|
|
x |
20 µm average thickness |
|
Indeterminate Avialan B |
Hwang (2011) |
|
|
x |
|
x |
|
|
x |
16 µm average thickness |
Sauropodomorpha |
|||||||||||
|
Plateosaurus engelhardti |
Sander (1999) |
10 |
40 |
x |
? |
|
x |
|
|
Columnar is very poorly developed; probably more divergent parallel |
|
cf. Diplodocus |
Sander (1999) |
|
150 |
|
|
x |
|
|
|
Pseudo-wavy (Sander, p. 68) |
|
Diplodocus longus |
Hwang (2011) |
440 |
490 |
|
x |
x |
x |
|
x |
465 µm average thickness |
|
Camarasaurus sp. |
Hwang (2011) |
700 |
1000+ |
x |
x |
x |
x |
|
|
850 µm average thickness |
|
Titanosauridae indet. |
Hwang (2011) |
|
|
x |
x |
x |
x |
|
x |
170 µm average thickness |
Dinosauria:Ornithischia |
|||||||||||
D:O:Stegosauria |
Stegosaurus sp. |
Hwang (2011) |
|
|
x |
|
x |
x |
|
|
30-40 µm average thickness |
D:O:Ankylosauria |
Ankylosauria indet. |
Sander (1999) |
|
60 |
|
x |
x |
|
|
|
|
|
Ankylosaurus magniventris |
Hwang (2005) |
|
60 |
x |
x |
x |
x |
|
|
|
|
Edmontonia rugosidens |
Hwang (2005) |
|
100+ |
x |
x |
x |
x |
|
|
|
|
Sauropelta edwardsi |
Hwang (2005) |
|
105 |
x |
x |
x |
x |
|
|
|
|
Euplocephalus |
Hwang (2009, 2011) |
35 |
65 |
x |
x |
x |
x |
|
x |
55 µm average thickness; originally identified as a pachycephalosaurid |
Dinosauria:Ornithischia:Euornithopoda |
|||||||||||
D:O:E: Hypsilophodontidae |
Thescelosaurus sp. |
Sander (1999) |
14 |
140 |
x |
|
x |
|
|
|
BUL thin |
|
Thescelosaurus sp. |
Hwang (2011) |
20 |
90 |
x |
x |
x |
|
|
x |
Hwang (2011) suspects Sander's (1999) specimen is not Thescelosaurus |
D:O:E:Dryomorpha |
Dryosaurus altus |
Hwang (2011) |
|
|
|
|
x |
x |
x |
x |
55-65 µm average thickness |
|
Camptosaurus dispar |
Hwang (2011) |
|
|
|
|
x |
|
x |
x |
|
D:O:E: Iguanodontidae |
Iguanodon sp. |
Sander (1999) |
100 |
150 |
|
|
x |
|
x |
|
Inner and outer wavy enamel |
|
Tenontosaurus tilleti |
Hwang (2005) |
|
100+ |
x |
x |
x |
|
|
x |
|
D:O:E: Hadrosauridae |
Hadrosauridae indet. |
Sander (1999) |
160 |
210 |
|
|
x |
|
x |
|
|
|
Hadrosaurinae indet. |
Hwang (2009) |
|
|
|
x |
|
|
|
x |
|
|
Anatosaurus sp. |
Sander (1999) |
100 |
100+ |
|
|
x |
|
x |
x |
BUL inverted |
|
Saurolophus sp. |
Hwang (2011) |
|
165+ |
|
|
x |
|
x |
|
115 µm average thickness |
|
Gilmoreosaurus mongoliensis |
Hwang (2005) |
|
|
|
|
x |
|
x |
|
|
|
Bactrosaurus johnsoni |
Hwang (2005) |
|
|
|
|
x |
|
x |
|
|
|
Kritosaurus navajovius |
Hwang (2005) |
|
|
|
|
x |
|
x |
|
|
|
Hypacrosaurus altispinus |
Hwang (2005) |
|
|
|
|
x |
|
x |
|
|
|
Corythosaurus casuaris |
Hwang (2005) |
|
|
|
|
x |
|
x |
|
|
|
Prosaurolophus maximus |
Hwang (2011) |
|
~200 |
|
|
x |
|
x |
|
135 µm average thickness |
Dinosauria:Ornithischia: Ceratopsia |
|||||||||||
|
Neoceratopsia indet. |
Hwang (2009) |
|
|
|
x |
|
|
|
|
Average 285 µm; originally assigned to Thescelosaurus sp. |
|
Psittacosaurus sp. |
Hwang (2005) |
|
|
|
x |
x |
|
|
? |
enamel voids |
|
Protoceratops |
Dauphin et al. (1988) |
|
|
x |
x |
x |
|
|
|
interpreted from pl. 1, figs. 7-8 (maxilla) and 12 (premaxilla) |
|
Leptoceratops gracilis |
Hwang (2005) |
|
420 |
|
x |
x |
|
|
x |
|
|
Protoceratops sp. |
Hwang (2005) |
|
120+ |
|
x |
x |
|
|
x |
|
D:O:C:Ceratopsidae |
Ceratopsidae indet. (Can) |
Sander (1999) |
150 |
|
|
x |
x |
x |
|
x |
|
|
Ceratopsidae indet. (WY) |
Sander (1999) |
|
|
|
|
|
|
|
|
|
|
Triceratops sp. |
Hwang (2005) |
|
325 |
|
x |
x |
|
|
x |
|
|
Centrosaurus apertus |
Hwang (2011) |
|
|
|
x |
x |
x |
|
x |
170-270 µm average thickness depending on position |
|
Pachyrhinosaurus canadensis |
Hwang (2011) |
|
|
|
x |
x |
x |
|
x |
170-270 µm average thickness depending on position |
Dinosauria:Ornithischia:Pachycephalosauridae |
|||||||||||
|
Pachycephalosauridae indet. A |
Hwang (2005) |
|
20 |
x |
|
|
|
|
|
anterior tooth, diverging parallel |
|
Pachycephalosauridae indet. B |
Hwang (2005) |
|
40 |
x |
x |
x |
|
|
|
posterior tooth, incipient columnar |
|
Pachycephalosauridae indet. C |
Hwang (2005) |
|
50 |
x |
x |
x |
|
|
|
posterior tooth, incipient columnar |
TABLE 2. Measurements of enamel thickness in the teeth of Revueltosaurus and Krzyzanowskisaurus sampled here.
Revueltosaurus callenderi enamel measurements from longitudinal section of NMMNH P-33798 |
|||
|
|
|
|
Figure |
Section |
Enamel thickness (µm) |
Measured at: |
3.2 |
Longitudinal |
4.87 |
end of [full width of] enamel (thinnest enamel) |
3.3 |
Longitudinal |
20.42 |
middle of frame |
3.4 |
Longitudinal |
36.23 |
middle of frame |
3.5 |
Longitudinal |
68.48 |
middle of frame |
3.6 |
Longitudinal |
115.56 |
top of frame (thickest enamel) |
3g |
Longitudinal |
114.88 |
left of frame (thickest enamel) |
3h |
Longitudinal |
152.13 |
bottom of frame (thickest enamel) |
3i |
Longitudinal |
103.34 |
middle of frame |
4.2 |
Longitudinal |
46.88 |
middle of frame |
4.3 |
Longitudinal |
50.08 |
middle of frame |
4.4 |
Longitudinal |
52.43 |
middle of frame |
4.5 |
Longitudinal |
53.93 |
middle of frame |
4.6 |
Longitudinal |
15.47 |
middle of frame |
4.7 |
Longitudinal |
31.36 |
middle of frame |
4.8 |
Longitudinal |
127.6 |
middle of frame |
"Tooth has total crown height (TCH) of 13.1 mm, total crown length (TCL) 8.1 mm" |
|||
|
|
|
|
Revueltosaurus callenderi enamel measurements from transverse section of NMMNH P-33797 |
|||
Figure |
Section |
Enamel thickness (µm) |
Measured at: |
3.11 |
Transverse |
51.5 |
on denticle |
3.12 |
Transverse |
53.41 |
middle of frame |
3.13 |
Transverse |
55.15 |
middle of frame |
3.14 |
Transverse |
59.66 |
middle of frame |
5.1 |
Transverse |
42.8 |
left of frame (EDJ visible) |
5.3 |
Transverse |
92.47 |
middle of frame |
5.4 |
Transverse |
50.77 |
middle of frame |
5.5 |
Transverse |
54.48 |
middle of frame |
5.6 |
Transverse |
53.32 |
middle of frame |
5.7 |
Transverse |
62.79 |
middle of frame |
5.8 |
Transverse |
60.04 |
middle of frame |
TCH: 6 mm+ (broken) |
|
TCL: ~6 mm |
|
|
|
|
|
Krzyzanowskisaurus hunti enamel measurements from longitudinal section of UCMP 165213 |
|||
Figure |
Section |
Enamel thickness (µm) |
Measured at: |
6.2 |
Longitudinal |
112.8 |
middle of frame |
6.3 |
Longitudinal |
138.89 |
left of frame (EDJ visible) |
6.4 |
Longitudinal |
151.25 |
right of frame (unbroken outer edge of enamel) |
TCH: ~6 mm (incomplete) |
|
TCL: 6 mm |
|
|
|
|
|
Krzyzanowskisaurus hunti enamel measurements from transverse sectionof UCMP 165211 |
|||
|
|
|
|
Figure |
Section |
Enamel thickness (µm) |
Measured at: |
7.1 |
Transverse |
55.38 |
middle of bend |
7.2 |
Transverse |
64.34 |
middle of frame |
7.3 |
Transverse |
50.49 |
middle of frame |
7.4 |
Transverse |
65.54 |
middle of frame |
7.5 |
Transverse |
63.38 |
middle of frame |
7.6 |
Transverse |
43.47 |
middle of frame |
7.7 |
Transverse |
61.82 |
middle of frame |
TCH: ~10.4 mm |
TCL: ~7.4 mm |
|
|