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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