Naturwissenschaften DOI 10.1007/00114-005-0065-y SHORT COMMUNICATION Ulrich Kuch . Johannes Müller . Clemens Mödden . Dietrich Mebs Snake fangs from the Lower Miocene of Germany: evolutionary stability of perfect weapons Received: 5 April 2005 / Accepted: 22 October 2005 # Springer-Verlag 2005 Abstract There is a general consensus that most of today’ s nonvenomous snakes are descendants of venomous snakes that lost their venomous capabilities secondarily. This implies that the evolutionary history of venomous snakes and their venom apparatus should be older than the current evidence from the fossil record. We compared some of the oldest-known fossil snake fangs from the Lower Miocene of Germany with those of modern viperids and elapids and found their morphology to be indistinguishable from the modern forms. The primary function of recent elapid and viperid snake fangs is to facilitate the extremely rapid, stab- like application of highly toxic venoms. Our findings therefore indicate that the other components of the venom- delivery system of Early Miocene vipers and elapids were also highly developed, and that these snakes used their venom in the same way as their modern relatives. Thus, the fossil record supports the view that snakes used their venoms to rapidly subdue prey long before the mid-Tertiary onset of the global environmental changes that seem to have supported the successful radiation of venomous snakes. Introduction Among living vertebrates, snakes have the most diverse, efficient, and sophisticated venom-delivery systems [8], consisting of large mucous–serous venom glands [12], ex- tensive associated muscles allowing for highly regulated high-pressure ejection of venom [32], and long tubular fangs facilitating deep injection into prey or enemies [7, 8]. All venomous snakes belong to the Colubroidea, which com- prises the vast majority of living snakes, and three separate lineages, the Atractaspididae, Elapidae, and Viperidae, which have independently evolved a venom-delivery system. The front-fanged members of these three lineages have tradition- ally been referred to as venomous snakes from a clinical point of view, because they have either caused human morbidity and mortality, or they are at least thought to be capable of doing so. They are also venomous snakes in a biological sense, because they use their oral gland secretions to subdue prey [10]. Most of the remaining modern colubroids are not considered venomous clinically, although a few have caused severe human envenomation and even fatalities [14, 23]. While many snakes need their body musculature not only for locomotion but also for prey constriction, the capability of envenoming prey enabled colubroids to uncouple their feeding and musculoskeletal systems. This allowed for the evolution of more rapid locomotion and thus a very different ecology, which probably evolved in concert with the evolution of grassland habitats during the Tertiary [22]. Recent studies [3, 8, 29] support the hypothesis that the presence of supralabial serous secretory cells and differ- entiated maxillary dentition is a synapomorphy of the Colubroidea, followed in the course of their evolutionary diversification by repeated reduction or loss in those groups that have traditionally been called “nonvenomous colubrids” [22, 28]. A wide range of possible biological functions has been proposed for the oral gland secretions of colubroids, but evaluating their biological role only from a pharmacological and physiological perspective may not be sufficient in a functional or evolutionary context [9, 10]. In fact, while the molecular arsenal of early colubroids can be inferred [2], this is not true for the state of their venom- U. Kuch . D. Mebs Zentrum der Rechtsmedizin, Klinikum der Johann Wolfgang Goethe-Universität, Kennedyallee 104, 60596 Frankfurt am Main, Germany J. Müller (*) Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road, Mississauga, Ontario, L5L 1C6, Canada e-mail: jmuller@utm.utoronto.ca Tel.: +1-905-8283980 Fax: +1-905-8283792 C. Mödden Institut für Geowissenschaften, LE Paläontologie, Johannes-Gutenberg-Universität Mainz, Becherweg 21, 55099 Mainz, Germany