New skull material of Pleistocene dwarf deer from Crete (Greece)

Abstract

In the Pleistocene faunas of the island of Crete, Cervidae was one of the most abundant taxa. Respective species vary in body size, including dwarfs, and skeletal morphology; however, the number of species and the identity of the mainland ancestor(s) are still debated. In this paper, we morphologically and morpho­metrically describe and analyze eight skulls of Cretan deer from a so far little known fossil site near Gerani, Rethymnon, Greece. The recorded character suite allows for affiliation to dwarfed Candiacervus Kuss, 1975, Candiacervus ropalophorus de Vos, 1984 and C. reumeri van der Geer, 2018. It comprises previously unknown unique traits, some of them hinting to sexual dimorphism. Comparisons of the Candiacervus skulls presented here with those of cervids belonging to Megalocerotini Brooke, 1828, s.s. and s.l. stress certain similarities; yet more material is needed to reconstruct Candiacervus’ phylo­genetic position. The newly detected craniodental specifics allow for more insights into island adaptation of Candiacervus; at the same time, they blur the morphological heritage of their mainland ancestors.

A Craniometric Analysis of the Subfamily Cervinae (Cervidae, Mammalia)

“…The fossil and modern osteological specimens utilized in this study are curated at various institutions, including the Institute of Zoology of the State University of Moldova (IZM), Republic of Moldova; the Institute of Zoology of the University of Wroclaw (IZW), Poland; the Museum of Geology and Paleontology of the University of Florence (MGUF), Italy; the Muséum national d'Histoire naturelle (MNHN), Paris, France; the Museum of Paleontology of the Department of Earth Sciences (MPS), University of Rome "Sapienza", Italy; the Natural History Museum "Grigore Antipa" (NHMB), Bucharest, Romania; the Natural History Museum of London (NHML), United Kingdom; the Natural History Museum "La Specola" (NHMF), University of Florence, Italy; the Paleontological Museum of the University "Claude Bernard" Lyon 1 (PMUL), France; the Faculty of Geography and History of the University of Barcelona (FGUB); and the State Museum of Natural History of Stuttgart (SMNH), Germany. Some cranial measurements of Cervus elaphus are adapted from Heptner and Tzalkin [14], while cranial measurements for Candiacervus ropalophorus are adapted from Schilling and Roessner [15]. Detailed information regarding cranial specimens, their collection numbers, institutions of curation, and measurements can be found in Table S1 of the Supplementary Materials.…”

“…The evolution of deer in conditions of insular isolation has long been recognized as a distinctive mode of evolution characterized by a suite of particular adaptations, forming a syndrome of responses to insular isolation. Among these adaptations, researchers often cite diminished body size, reduced and simplified antlers, shortened limb bones, abbreviated splanchnocranium, and generally paedomorphic cranial features [12,15,26,27]. Researchers have paid particularly close attention to Pleistocene insular deer of the Mediterranean.…”

“…Candiacervus ropalophorus. The genus Candiacervus encompasses insular deer native to Crete, which have undergone extreme reduction in body size and significant cranial shape transformation due to evolution in isolated island conditions [12,15,27,29]. The body size of Candiacervus species falls between that of Hyelaphus and Muntiacus.…”

“…Candiacervus ropalophorus is characterized by a significantly reduced relative length of the facial part of the skull [15]. The measurement from the orbit to the prosthion point attains 30% of the condylobasal length, representing an outlier value among cervines, where the relative length of the face typically ranges from 50 to 65%.…”

“…One plausible explanation for this peculiar feature in insular deer is their diminished olfactory capacities in the absence of carnivores in the insular ecosystem [26]. The braincase of C. ropalophorus is relatively short, as in continental Praemegaceros [15], while its occiput maintains a normal relative breadth for cervinae (Figure 11).…”