COMPARATIVE MORPHOLOGY OF THE SKIN OF THE WATER DEER (HYDROPOTES INERMIS) AND MUNTJACS (MUNTIACUS SPP.), CERVIDAE, ARTIODACTYLA

The fur and skin glands of phylogenetically close species with partially overlapping distribution ranges were comparatively studied using light and electron microscopy: the Water deer (Hydropotes inermis) and the muntiacs (Muntiacus munijak, M. reevesi, M. vaginalis and M. vuquangensis). The color and diversity of the fur, as well as the development of specific skin glands were shown to vary in the species compared, demonstrating features of adaptation to different habitats, since the former prefers near-water biotopes, vs the latter which dwell in savannas or forests. The fur color of the Water deer is variegated, while that of the muntiacs is more uniform, although color markings are present. It performs a camouflage function in accordance with the habitats of these deer. The Water deer fur is significantly heterogeneous in hair size (especially on the back, side and thighs), as well as the knottiness of the guard hairs, which protect it when moving in thickets of thorny bushes and sharp-leaved grasses along the banks of rivers and swamps. The species compared have no abundant underfur, this being typical of inhabitants of the temperate monsoon and tropical zones where there is no need in a powerful warm cover. However, the medulla of the guard hairs is quite well developed, increasing their thermal insulation through protecting the covers from seasonal and daily fluctuations in temperature and humidity. The architecture of the medulla in the hairs of the Water deer is similar to that of the hairs of elk, musk deer, roe deer and red deer, whereas in the muntiacs it is more simply structured and similar to that of the Sika deer, thus suggesting a low phylogenetic status of these species. The metric characteristics of the cuticle ornament reveal similarities in this feature between the Water deer and the Alceinae deer, while in the muntiacs it demonstrates, like in the European roe deer and the Siberian musk deer, isolation from the main group of species of the genus Cervus, in agreement with the taxonomy of the infraorder Pecora. The set of specific skin glands is broad in the study species, which is typical of deer, but there are also additional glandular formations, such as the inguinal glands in the Water deer (the only case among the deer), the frontal and mental glands, whereas the tarsal and metatarsal glands are absent. These differences are probably associated with the peculiarities of marking activity in different habitats: the Water deer marks grassy and shrubby vegetation, and probably lying downs, vs the muntiacs that leave marks on the trunks, branches and crowns of trees and shrubs.

deer, Hydropotinae, Cervulinae, hair, glands, architecture, SEM, comparative morphological analysis, adaptations