title

Comparative characteristics of incisor enamel structure in selected extinct and extant horse forms

author(s)

Vitalii Demeshkant (orcid: 0000-0002-4838-4897) [1]
Leonid Rekovets (orcid: 0000-0001-9934-7095) [1,2]

affiliation

Wroclaw University of Environmental and Life Sciences (Wrocław, Poland)
[2] National Museum of Natural History, NAS of Ukraine (Kyiv, Ukraine)

bibliography

Theriologia Ukrainica. 2026. Vol. 31: 54–68.

DOI

language

English, with Ukrainian summary, titles of tables, captures to figs

abstract

The present study reports the results of a comparative analysis of the ultrastructure of incisor enamel in selected extinct species, historical forms, and extant representatives of the genus Equus, aimed at identifying evolutionary and functional trends in its structural organization. The material examined comprised incisors of Equus suessenbornensis from the Middle Pleistocene of Germany, E. latipes from the Upper Pleistocene of Ukraine, E. caballus from different historical periods of the Holocene, as well as modern horse breeds of Central Europe. The study was carried out on horizontal and vertical sections of teeth and enamel using electron microscopy. All examined forms were characterized by a common enamel structural pattern, including Hunter–Schreger Bands (HSB), the portio interna (PI) and portio externa (PEx) layers, prismatic enamel (PE), and interprismatic matrix (IPM). Differences were revealed in the degree of development and spatial organization of these structures. Pleistocene forms, particularly E. latipes, showed features of a more archaic enamel organization, including weak differentiation of prism bundles and gradual transitions between structural types. In contrast, E. suessenbornensis demonstrated a more complex enamel structure compared with E. latipes. Historical and modern horses were characterized by a more complex enamel architecture, a more pronounced undulating arrangement of prisms and structural decussation, as well as considerable variability in the organization of PI and PEx layers and PE and IPM components. These features may reflect both the evolutionary history of the genus Equus and adaptations associated with changes in environmental conditions, feeding patterns, and domestication processes. The study confirmed that Equidae tooth enamel is a morphological feature with a relatively stable structure and reflects functional adaptations. The results indicate that the ultrastructure of incisor enamel retains phylogenetically informative features and may serve as an additional source of data in taxonomic, paleontological, and paleoecological studies.

keywords

horses, breeds, teeth, enamel structure, Pleistocene, Holocene

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