Palaeodiversity 2: 379–385; Stuttgart, 30.12.2009. 379 Taphonomic reinterpretation of a bone sample of endemic Pleistocene deer from Crete (Greece): osteoporosis versus regurgitation ISABELLE ROBERT ATTARD & JELLE W. F. REUMER Abstract A sample of fossil deer remains (genus Candiacervus) from Mavro Mouri cave, Crete, Greece is studied be- cause a large proportion shows aberrant, seemingly pathological changes to the morphology and the structure of the bones. Here we show that the aberrant appearance of the Mavro Mouri bone sample can be understood through a simple taphonomical explanation: post-mortem damage to the bones inflicted by bearded vultures (Gypaetus bar- batus). Hence they are not osteoporotically altered due to supposed malnutrition, as proposed before. This conclu- sion has a bearing on our understanding of island evolution, as it eliminates a supposed direct relation between persistent malnutrition on the one hand, and island dwarfing on the other. Keywords: Candiacervus, Gypaetus barbatus, taphonomy, malnutrition, osteoporosis, island evolution, insular dwarfism, endemism. Zusammenfassung Es werden fossile Hirsch-Reste (Gattung Candiacervus) aus der Mavro Mouri Höhle, Kreta, Griechenland, untersucht, von denen ein großer Teil ungewöhnliche, scheinbar pathologische Veränderungen ihrer Morphologie und Struktur zeigt. Diese Veränderungen der Knochen können durch einen einfachen taphonomischen Prozess erklärt werden. Es sind durch den Bartgeier (Gypaetus barbatus) verursachte postmortale Beschädigungen. Die Veränderungen sind also keine durch Mangelernährung verursachten Osteoporose-Erscheinungen wie bisher an- genommen wurde. Diese Erklärung beeinflusst unser Verständnis der Evolution von Inselfaunen, da sie eine ver- mutete direkte Beziehung zwischen fortdauernder Mangelernährung und Zwergwuchs ausschließt. Contents 1. Introduction ............................................................................379 2. Material and methods .....................................................................380 3. Description of the material. 380 4. A taphonomical hypothesis ................................................................381 5. Discussion ..............................................................................382 5.1. Taphonomy .........................................................................382 5.2. Evolutionary theory ..................................................................384 6. References .............................................................................384 1. Introduction hopping’ from Asia Minor during phases of low sea-lev- el. Like most islands in the Mediterranean Basin, the is- Mavro Mouri is a karstic locality on the north coast of land of Crete harboured a typical endemic mammal fauna Crete, a few kilometers west of the town of Rethymnon. during several phases of the Pleistocene (REESE 1996 and The site has yielded a large sample of bones of the Late articles and references therein). During Early and Middle Pleistocene endemic fossil deer Candiacervus cretensis Pleistocene times, the island harboured endemic elephants and related taxa of the Cretan cervid species flock (e. g., (Mammuthus spp.), hippo’s (Hippopotamus creutzburgi KUSS 1975; SONDAAR 1977; DE VOS 1979, 1984). A consider- BOEKSCHOTEN & SONDAAR, 1966) and a suite of rat-sized able percentage of these bones show a phenomenon that rodents (Kritimys spp.). During the Late Pleistocene the appears to be persistently misunderstood in the paleonto- fauna consisted of an endemic rodent (Mus minotaurus logical literature, i. e., an aberrant morphology showing, BATE, 1942), a shrew (Crocidura zimmermanni WETTSTEIN, among other, a thin cortex, large openings in the cortex, 1953), a species flock of cervid deer (Candiacervus spp.) and strangely worn articulation surfaces. It has led re- and a lutrine otter (Isolalutra cretensis SYMEONIDIS & searchers to various explanations. The bizarre condition of SONDAAR, 1975). There appear to have been at least two the bones has been explained as being the result of either different immigration waves and subsequent extinctions. malnutrition, of disease (osteoporosis, anaemia), or of the The animals could have reached Crete by means of ‘island influence of boring insects (or insect larvae). It was 380 PALAEODIVERSITY 2, 2009 2. Material and methods Material from the Mavro Mouri cave was excavated in the 1960’s/1970’s by several groups, among which a team of paleontologists from Utrecht University under the guid- ance of the late Dr. P. Y. S ONDAAR. Deer material was de- scribed by DE VOS (1979, 1984), while other remains were subsequently published by several researchers (see REESE 1996 for an overview). Even before the formal description of the deer material by DE VOS (1979, 1984) it was apparent that a large proportion of the deer bones from Mavro Fig. 1. First published depiction of the regurgitated bones from Mouri (more specifically from Mavro Mouri IV level C) Mavro Mouri, from SONDAAR 1977. had an aberrant appearance; this was preliminarily de- scribed and illustrated by SONDAAR (1977). Before or since, other authors have written about it (KUSS 1975; BRABER SONDAAR (1977: 694–695) who provided the following de- 1981). The Mavro Mouri Candiacervus material is now in scription: “At one Pleistocene locality on Crete, most of the collection of Naturalis, the National Museum of Natu- the deer bone exhibited osteoporosis. (Osteoporosis is a ral History, Leiden, the Netherlands, and is temporarily rarefying condition of bones which lose much of their being kept in the Natural History Museum in Rotterdam, mineral matter and become fragile and often deformed). the Netherlands. The bones are thin, the nutritive canals are very wide and In order to identify the agent responsible for the bone the articular surfaces are sharp-edged. Evidently there accumulation, we used two criteria: (1) the frequency of was a failure in bone formation while bone loss was pro- skeletal elements, and (2) the presence or absence of marks ceeding normally.” indicating alteration of the bone. The material here pub- Of these different explanations, the suggestion of se- lished was studied by the senior author during a short stay vere malnutrition and subsequent osteoporosis (SONDAAR in Rotterdam. The total amount of material consists of 1977) had led scientists to propose malnutrition as one of 3029 bones and bone fragments. Measurements were the possible reasons for dwarfing in larger island mam- made with manual calipers, photographs were made with mals (e. g., KÖHLER & MOYA-SOLA 2005). It astonished us a Nikon Coolpix 3MPixel camera. that similar malnutrition-related osteological phenomena have not been described from other islands, neither in the Mediterranean Basin nor in other regions. However, this 3. Description of the material should have been expected if the malnutrition caused the dwarfing, because dwarfing is a globally observable char- The number of bones studied is given in Tab. 1, where acteristic of insular larger mammals. A proper under- the different elements are presented in a sequence from standing of the osteological phenomena observed in the the most proximal to the most distal position in the skele- Mavro Mouri sample (and there only and so far not in ton. We based our studies on the quantitative results of other samples from Cretan sites) is thus of importance for BRABER (1981), and in addition we searched through the the theory of island evolution in larger mammals. boxes labeled ‘indeterminate’ in order to retrieve more The original black-and-white line drawings provided material. The bones were then separated in two categories: by SONDAAR (1977, here reproduced as Fig. 1) do not allow with or without indications of alteration. The results are precise identification of the causative agent. New discov- given in Tab. 2, leaving out the cranial and axial material. eries in taphonomy (e. g., ROBERT & VIGNE 2002) allow us The following features are observed on the bones: to re-evaluate the original diagnosis of malnutrition and – thinning of the cortex in the diaphysis osteoporosis, and provide a new explanation for the strange – roughening of the cortical surface, ultimately leading bone deformations. to formation of holes in the bone surface – enlargement of foramina Acknowledgements – deformation of the articular surfaces The comparative study about Mavro Mouri and the bearded – subtle size reduction of the entire skeletal element vulture was supported by the CNRS (APN program) ‘Référen- tiels taphonomiques créés par des agents non humains mod- These features surprisingly conform to the results pro- ernes’. Dr. DAV I D MAYHEW (Rotterdam) and Dr. JOHN DE VOS vided by ANDREWS (1990) for digestion of microfaunal re- (Leiden) critically read the manuscript. mains regurgitated by nocturnal raptors. ATTARD & REUMER, TAPHONOMIC REINTERPRETATION OF PLEISTOCENE DEER BONES 381 Tab. 1. Relative presence of skeletal elements in the Mavro cal changes). This interpretation, viz. the impression that Mouri IV C sample, arranged in an increasingly distal order the observed phenomena are due to disease of some kind, (NISP = number of identified specimens). has haunted literature since. In different publications, the body Total following three explanations were subsequently provided: Skeletal element NISP % region % P o l y c h a e t a . – Boreholes in the bone were suppos- antler 98 5.0 edly made by polychaete worms of the genus Polydora maxillary 42 2.1 cranial 24.2 (Polychaeta, family