Table 1 Eruption sequence of permanent cheek teeth in living and extinct equids.

From: First Radiological Study of a Complete Dental Ontogeny Sequence of an Extinct Equid: Implications for Equidae Life History and Taphonomy

Species

Fossil site

Age

Eruption sequence of permanent cheek teeth

Crown heighta

Taxonomic adscription

Mortality type

Reference

Equus caballus

 

Modern

m1, m2, p2, p3, m3, p4

Hypsodont

Equini (Equinae)

 

40

Equus asinus

 

Modern

m1, m2, p2, p3, p4, m3

Hypsodont

Equini (Equinae)

 

39

Equus hemionus hemionus

 

Modern

m1, m2, (p2, p3, m3), p4

Hypsodont

Equini (Equinae)

 

63

Equus burchelli antiquorum

 

Modern

m1, m2, (p2, p3, m3), p4

Hypsodont

Equini (Equinae)

 

36

Equus burchelli

 

Modern

m1, m2, p2, p3, p4, m3

Hypsodont

Equini (Equinae)

 

64

Equus zebra zebra

 

Modern

m1, m2, p2, p3?, p4, m3

Hypsodont

Equini (Equinae)

 

65

Equus zebra hartmannae

 

Modern

m1, m2, (p2, p3, m3), p4

Hypsodont

Equini (Equinae)

 

66

Equus simplicidens

Hagerman Horse Quarry (USA)

Late Pliocene

m1, m2, (p2, p3), m3, p4

Hypsodont

Equini (Equinae)

Catastrophic (but previously interpreted as attritional)

51

Protohippus cf. P. perditus

Verdigre Quarry (USA)

Early Pliocene

m1, m2, (p2–p4) b , m3

Hypsodont

Equini or Protohippini (Equinae)

Catastrophic

19

Hipparion chiai and Hipparion cf. H. coelophyes

Lamagou Fauna of Fugu (China)

Late Miocene

m1, m2, p2, p3, (p4, m3)

Hypsodont

Hipparionini (Equinae)

Not reported

29

Hipparion sp.

Batallones-10 (Spain)

Late Miocene

m1, m2, (p2, p3), p4, m 3

Hypsodont

Hipparionini (Equinae)

Attritional

This study

Merychippus primus

Sheep Creek (USA)

Middle Miocene

m1, m2, (p2, p3), p4, m3

Mesodont

Primitive Equinae

Catastrophic

22

Parahippus leonensis

Thomas Farm (USA)

Early Miocene

m1, m2, (p2–p4) c , m3

Brachydont

Anchitheriinae

Attritional (but taphonomic underrepresentation of juvenile remains)

24

Archaeohippus blackbergi

Thomas Farm (USA)

Early Miocene

m1, m2, (p2–p4) c , m3

Brachydont

Anchitheriinae

Intermale combat

26

Propalaeotherium hassiacum

Geiseltal (Germany)

Middle Eocene

m1, m2, m3, (p2–p4)

Brachydont

Palaeotheriidae (Equoidea)

Not reported

28

  1. Fossil species are listed from younger to older. The mortality type is provided for fossil sites. Sequences where the p4 erupts before the m3 are in bold. Sequences where the m3 erupts before the p4 are in italics. Parentheses enclose teeth with more or less simultaneous eruption timing. aCrown height follows Mihlbachler et al.10. bThe order of eruption of premolars is not specified. cThe authors specify that the p4 erupts at the same time as the other premolars.
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