Blackwell Science, LtdOxford, UKZOJZoological Journal of the Linnean Society0024-4082The Lin- nean Society of London, 2005? 2005 1443 363377 Original Article FUNCTIONAL MORPHOLOGY OF P. OGYGIAM. J. SALESA ET AL. Zoological Journal of the Linnean Society, 2005, 144, 363–377. With 11 figures Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: Downloaded from https://academic.oup.com/zoolinnean/article-abstract/144/3/363/2627519 by guest on 18 May 2020 implications for the origins of the machairodont killing bite MANUEL J. SALESA1*, MAURICIO ANTÓN2, ALAN TURNER1 and JORGE MORALES2 1School of Biological & Earth Sciences, Byrom Street, Liverpool John Moores University, Liverpool, L3 3AF, UK 2Departamento de Palaeobiología, Museo Nacional de Ciencias Naturales-CSIC, José Gutiérrez Abascal, 2. 28006 Madrid, Spain Received January 2004; accepted for publication March 2005 The skull and cervical anatomy of the sabre-toothed felid Paramachairodus ogygia (Kaup, 1832) is described in this paper, with special attention paid to its functional morphology. Because of the scarcity of fossil remains, the anatomy of this felid has been very poorly known. However, the recently discovered Miocene carnivore trap of Batallones-1, near Madrid, Spain, has yielded almost complete skeletons of this animal, which is now one of the best known machairodontines. Consequently, the machairodont adaptations of this primitive sabre-toothed felid can be assessed for the first time. Some characters, such as the morphology of the mastoid area, reveal an intermediate state between that of felines and machairodontines, while others, such as the flattened upper canines and verticalized mandibular symphysis, show clear machairodont affinities. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144, 363-377. ADDITIONAL KEYWORDS: Batallones – Carnivora – Felinae – functional anatomy – Mammalia – Miocene – pantherine – Turolian – Vallesian. INTRODUCTION straint in each group, still remain essentially a mystery. Sabre-toothed predators have evolved several times One of the reasons for this lack of resolution is the among different orders of mammals and in somewhat fact that within each convergent group of sabre-tooth different forms even among nonmammalian synapsids predators it is usually the most derived, crown taxa (Turner & Antón, 1997). The similarities in detail that are the best known anatomically while the basal between often completely unrelated taxa are so taxa have much poorer fossil records. Thus, among remarkable that the sabre-tooth adaptation has the Machairodontinae (the sabre-toothed subfamily become a text-book example of convergent evolution. within the extant family Felidae), the crown taxa such However, exactly how it evolved in each case, what the as Homotherium and Smilodon from the Pliocene and main evolutionary pressures were and where the Pleistocene have been known for many decades balance lay between adaptation and phylogenetic con- thanks to complete skulls and skeletons, while the fos- sil record of basal genera such as Paramachairodus from the Late Miocene have traditionally consisted of *Corresponding author. E-mail: [email protected] scarce and fragmentary material. The situation is not © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144, 363–377 363 364 M. J. SALESA ET AL. very different across the various families of mam- Consequently, no studies of the functional morphology malian sabre-tooths, including the Nimravidae and of Paramachairodus have yet been published. Barbourofelidae among the Carnivora (Peigné, 2002; The discovery of Batallones-1, a new Late Miocene Morlo, Peigné & Nagel, 2004) and the marsupial fossil locality near Madrid, Spain, has yielded a large Thylacosmilidae (Argot, 2003, 2004). number of specimens of P. ogygia, with at least 24 The result of this unbalanced fossil record is that individuals represented and including several skull emphasis on a series of highly convergent crown taxa and mandibles (Salesa, 2002). This locality has been has led to an exaggerated perception of homogeneity interpreted as a carnivore trap based on its special in adaptation and to suggestions that the so-called characteristics, such as the presence of an extremely ‘sabre-tooth complex’ would be under ‘strong pleiotro- high percentage of carnivores (98%) and the morphol- Downloaded from https://academic.oup.com/zoolinnean/article-abstract/144/3/363/2627519 by guest on 18 May 2020 pic control’ (Dawson et al., 1986). A better fossil record ogy of the site, essentially a hole with semivertical and a detailed study of basal taxa would greatly help walls (Antón & Morales, 2000; Morales et al., 2000). to clarify the origins of this predatory adaptation, in The carnivore guild of Batallones-1 also includes the particular of the ‘canine shear-bite’, the derived killing lion-sized sabre-toothed felid Machairodus aphanis- bite modality that has been proposed as a functional tus, the bear-dog Amphicyon sp. aff. A. castellanus, the explanation of the morphology of crown sabre-toothed primitive hyaenid Protictitherium crassum and other taxa such as Smilodon and Homotherium (Akersten, carnivores such as mustelids and Simocyon batalleri, 1985; Antón & Galobart, 1999) a medium-sized carnivore related to the extant red The genus Paramachairodus Pilgrim, 1913 includes panda (Antón & Morales, 2000; Morales et al., 2000; primitive, leopard-sized sabre-toothed cats known Salesa & Fraile, 2000; Salesa, 2002; Antón et al., from the Late Miocene faunas of Eurasia (Beaumont, 2004a; Peigné et al., 2005). 1975; Morales & Soria, 1977; Montoya, 1994; Morlo, In this paper we present a functional analysis of the 1997; Salesa et al., 2003). Two species have been tra- cranial, mandibular and cervical anatomy of P. ogygia, ditionally referred to this genus: P. ogygia (Kaup, concentrating on aspects directly related to the canine 1832), of Vallesian-Early Turolian age (MN 9–11 of shear-bite adaptation. This analysis has revealed an Mein, 1975) and P. orientalis (Kittl, 1887) of Turolian intermediate morphology between the extant felines age (MN 11–13), distinguished by several dental and the more derived sabre-toothed cats such as traits. The more primitive species, P. ogygia, had non- Smilodon or Homotherium. crenulated upper canines, a P4 without ectostyle and with a strong protocone, and a P3 with a posterointer- MATERIAL AND METHODS nal expansion. P. orientalis had crenulated upper canines, a P4 with a well marked ectostyle as well as a Functional study of the cranial and cervical anatomy reduced, backwardly displaced protocone and a P3 of Paramachairodus ogygia has been possible because reduced in size and without posterointernal expansion of the great number of newly available fossils of this (Salesa et al., 2003). species: a total of 16 skulls, 12 mandibles and several In 1924, Zdansky created the species P. maximiliani vertebrae belonging to the Batallones-1 assemblage. for a damaged skull from the Late Miocene of China. All the material is housed at the Museo Nacional de The differences between this third species and Ciencias Naturales-CSIC in Madrid, Spain. Compari- P. orientalis are largely confined to the more curved sons with other Felidae have been made using the upper canines of P. maximiliani, where there are extant felines Panthera leo, Panthera tigris, Panthera crenulations on both keels (Zdansky, 1924). These pardus, Panthera onca, Uncia uncia, Neofelis nebu- characters are now considered to be of little systematic losa, Caracal caracal, Lynx pardina and Puma con- value, because crenulations are not equally evident in color, belonging to the collections of the Museo both keels. Thus for most authors, P. maximiliani is a Anatómico de la Universidad de Valladolid and Museo synonym of P. orientalis (Pilgrim, 1931; Beaumont, Nacional de Ciencias Naturales (Madrid). 1978; Salesa, 2002; Salesa et al., 2003). We also used published information on modern felid The anatomy of Paramachairodus has been largely anatomy (Barone, 2000; Reinhard & Jennings, 1935; unknown, because it is present in only a few fossil Sisson & Grossman, 1962) and on the morphology of localities such as Pikermi (Greece, MN 12), Maragha other, more derived sabre-toothed cats such as Smilo- (Iran, MN 11) or Eppelsheim (Germany, MN 9) and don fatalis and Homotherium latidens. The latter taxa represented by relatively scarce material. Most finds were chosen as the ideal reference for comparison with have been of dentitions. While it has long been clear P. ogygia because they exemplify the most derived that Paramachairodus was a sabre-toothed cat, the state for the sabre-toothed adaptations within the absence of more extensive anatomical information has Machairodontinae, whilst P. ogygia occupies a near meant that its machairodont adaptations and wider basal position in the same subfamily. The degree of aspects of its palaeobiology have remained unknown. machairodont adaptations appears to be essentially © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144, 363–377 FUNCTIONAL MORPHOLOGY OF P. OGYGIA 365 independent of such body size differences as those In the more derived members of this group, the observed between P. ogygia and the referred taxa. paraoccipital process becomes very reduced, almost Differences in the height of the crown