Extinct genus of deer
Candiacervus is an extinct genus of deer native to Pleistocene Crete. Due to a lack of other herbivores, the genus underwent an adaptive radiation, filling niches occupied by other taxa on the mainland. Due to the small size of Crete, some species underwent insular dwarfism, the smallest species, "C. ropalophorus", stood about at the shoulders when fully grown, while other species were relatively large and comparable in size to mainland deer species. Some species ("C. ropalophorus") are noted for their peculiar, elongate club-shaped antlers, though other species have more normal antlers.
Taxonomy.
The Cretan deer is a typical example of taxonomical problems involving endemic insular mammals, due to the much larger variety than on the mainland, and the strong endemism. This obscures taxonomy, because many endemic features of "Candiacervus" are not unique but are found in other island deer as well, such as "Cervus astylodon" (Ryukyu Islands) and "Hoplitomeryx" (Southern Italy).
De Vos (1979, 1984, 1996) identified eight morphotypes into one genus ("Candiacervus"), whereas Capasso Barbato (1992) included the larger species, "rethymnensis", "major" and "dorothensis", in "Cervus" (subgenus "Leptocervus") and the smaller species "ropalophorus" and "cretensis" in "Megaloceros" (subgenus "Candiacervus"), implying two different ancestors, and she also did not recognize sp. II with its three morphotypes, instead referring it to "ropalophorus". A new paper published in 2018 rejected the conclusion of Capasso Barbato (1992) and formally named the three morphotypes of De Vos' "Candiacervus" sp. II "C. devosi", "C. listeri", and "C. reumeri".
On the nearby island of Karpathos, Kuss found deer which were, in his view, similar to the Cretan deer. Therefore, he grouped his species "pygadiensis" and "cerigensis" under the genus "Candiacervus", but this needs further confirmation. As long as no direct link with Crete is attested, the deer genus of Karpathos is questioned, and better referred to as "Cervus".
They were traditionally considered to be related to the giant Irish elk ("Megaloceros giganteus") with some experts regarding "Candiacervus" as a subgenus of "Megaloceros". However, van der Geer (2018) finds them closer to fallow deer ("Dama"), while Croitor has suggested that the genus is closely related to the giant deer genus "Praemegaceros".
Description.
The Cretan deer is represented by no less than eight different morphotypes, ranging from dwarf size with withers height of about to very large with withers height of about , spanning a body mass range from in the smallest species "C. ropalophorus" to in the largest species "C. major." This is explained as an adaptive radiation following ecological release to occupy available niches. The larger species had proportionally longer legs than mainland deer, while the dwarf species had proportionally shorter legs. The large size of the only known individual of "C. major" may be due to pituitary gigantism, in which case the species may be a synonym of one of the smaller species, perhaps the red deer sized "C. dorothensis", which is suggested to weigh around . The short legs of the dwarf species is suggested to be an adaptation to a goat-like niche of climbing around on rocky terrain and consuming low quality foliage. The antler morphology was highly varied, in some of the dwarf species like "C. ropalophorus," the antler was simplified and greatly elongated into a club like structure unique among deer, while others retained a more typical antler morphology. The club-like antlers of "C. ropalophorus" and similar forms were probably only used for display rather than combat. The antler and skull morphology is unknown in the largest species.
Ecology.
The fauna of which "Candiacervus" is an element is called Biozone II, or the "Mus" Zone (after the "Mus" genus of mice). This fauna inhabited Crete between the late Middle and Late Pleistocene, approximately 0.3 to 0.01 million years ago. It succeeds the "Kritimys" biozone, which spanned the Early to early Middle Pleistocene.
The typical terrestrial mammalian fauna elements of this biozone aside from "Candiacervus" are a lineage of mice ("Mus bateae", "M. minotaurus"), a dwarf elephant ("Palaeoloxodon creutzburgi"), the Cretan otter ("Lutrogale (Isolalutra) cretensis"), and the Cretan shrew ("Crocidura zimmermanni").
Despite living in an environment free of large terrestrial predators, the species of "Candiacervus" exhibited relatively high rates of juvenile mortality, with likely causes of death being accidents and malnutrition. The growth rate of the bones of dwarf "Candiacervus" was relatively slow compared to living deer. Adult individuals are suggested to have had relatively long lifespans compared to extant ruminants of a similar body size, with some individuals of dwarf "Candiacervus" reaching a lifespan of 18 years.
Extinction.
The extinction of "Candiacervus" may be due to the arrival of humans at the end of the Pleistocene. They could have exterminated the deer either actively by hunting, or passively by destroying its habitat. Another option is a gradual depletion of the ecosystem, as indicated by the finding of a complete herd consisting of individuals suffering a bone disease of an osteosclerotic nature. The impact of paleolithic humans is at present still unproven, partly because of the scarcity on published fauna lists from archaeological sites (except for Knossos), partly because of the insecurely dated materials.
In 2018, it was proposed that Asphendou Cave petroglyphs in western Crete depicted "Candiacervus," suggesting that humans and "Candiacervus" chronologically overlapped on the island.