New material of the enigmatic giant viperid Laophis crotaloides (Squamata, Serpentes) from the Pliocene of Greece, with comments on reptilian gigantism in the Neogene of Southeastern Europe.
Abstract:
A fragmentary isolated vertebra from the early Pliocene of Megalo Emvolon (also known Karabournou) in Northern Greece is referred to the gigantic extinct viper Laophis crotaloides Owen. This taxon was originally named on the basis of 13 vertebrae recovered from Megalo Emvolon in 1857, and subsequently lodged in the collection of The Natural History Museum in London. Unfortunately, the type remains have since been lost and the species thus ignored or relegated to a nomen dubium, in spite of its estimated body length having potentially exceeded 3.5 metres. The incomplete and isolated nature of the new Laophis specimen hinders resolution to lower taxonomic levels. However, the fossil can be unequivocally placed within Viperidae because of its proportionally wide cotyle and condyle (the latter being markedly robust), probable presence of a hypapophysis, and most notably its dorsally tilted prezygapophyseal facets. Moreover, a multivariate quantitative approach supports previous assertions of large body size with an estimated maximum length and body mass, comparable to, if not larger than Lachesis muta, the largest extant viperid - a size that distinguish Laophis as amongst the largest extinct or extant venomous snakes ever known. The presence of a colossal viperid within the late Neogene ecosystems of mainland Greece is also significant because it concurs with the distribution of other gigantic Mio-Pliocene reptiles, including the large elapid Naja sp., another substantial but indeterminate species of Vipera, the varanid lizard Varanus marathonensis, and the colossal tortoises Cheirogaster. Similar coeval taxa have been found throughout the Balkan peninsula, southwestern Europe, and Asia Minor, and coincide with the onset of widespread climatic cooling during the late Miocene–late Pliocene. The spread of savannah grasslands throughout Mediterranean Europe during this time has been used to explain increased body sizes in herbivorous tortoises via dietary selection for greater consumption of C4 vegetation. However alternative ecological and/or physiological factors must be sought for large ectothermic predators, which would have had to effectively compete within a trophic system otherwise dominated by a broad range of mammalian carnivores.
http://www.academia.edu/8080438/New_material_of_the_enigmatic_giant_viperid_Laophis_crotaloides_Squamata_Serpentes_from_the_Pliocene_of_Greece_with_comments_on_reptilian_gigantism_in_the_Neogene_of_Southeastern_Europe._Abstract_Book_and_Field_Trip_Guide_XII_Annual_Meeting_of_the_EAVP_Torino_pp._68
