Candiacervus is an extinct genus of deer native to Pleistocene Crete.[1] 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,[2] the smallest species, C. ropalophorus, stood about 40 centimetres (16 in) at the shoulders when fully grown,[3] 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.
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,[4] such as Cervus astylodon (Ryukyu Islands) and Hoplitomeryx (Southern Italy). De Vos (1979, 1984, 1996)[5][6][7] identified eight morphotypes into one genus (Candiacervus), whereas Capasso Barbato (1992)[8] 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.[9]
On the nearby island of Karpathos, Kuss[10] 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, with some experts regarding Candiacervus as a subgenus of Megaloceros.[8] However, van der Geer (2018) finds them closer to fallow deer (Dama).[9]
The Cretan deer is represented by no less than eight different morphotypes, ranging from dwarf size with withers height of about 40 centimetres (16 in) to very large with withers height of about 165 centimetres (65 in),[6] spanning a body mass range from 27.8 kilograms (61 lb) in the smallest species C. ropalophorus to 245.4 kilograms (541 lb) 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.[11] 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,[12] which is suggested to weigh around 170.1 kilograms (375 lb).[11]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.[13] 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.[9] The antler and skull morphology is unknown in the largest species.[11]