Muscle attachments in the mastoid region of the skull of extant felids are studied through dissection of two adult tigers Panthera tigris (Linnaeus, 1758) Pocock, 1930, a lion Panthera leo (Linnaeus, 1758) Pocock, 1930 and a puma Puma concolor (Linnaeus, 1771) Jardine, 1834, providing for the first time an adequate reference for the study of the evolution of that region in sabretoothed felids. Our study supports the inference by W. Akersten that the main muscles inserting in the mastoid process in sabretooths were those originating in the atlas, rather than those from the posterior neck, sternum and forelimb. Those inferences were based on the anatomy of the giant panda, Ailuropoda melanoleuca (David, 1869) Milne-Edwards, 1870, raising uncertainties about homology, which were founded, as revealed by our results. The mastoid muscle insertions in extant felids differ in important details from those described for Ailuropoda, but agree with those described for domestic cats, hyenas and dogs. The large, anteroventrally projected mastoid process of pantherines allows a moderate implication of the m. obliquus capitis anterior in head-flexion. This contradicts the widespread notion that the function of this muscle in carnivores is to extend the atlanto-cranial joint and to flex it laterally, but supports previous inferences about the head-flexing function of atlanto-mastoid muscles in machairodontines. Sabretooth mastoid morphology implies larger and longer-fibred atlanto-mastoid muscles than in pantherines, and that most of their fibres ran inferior to the axis of rotation of the atlanto-occipital joint, emphasizing head-flexing action.

We update the systematics and comparative anatomy of the genus Hispanomeryx Morales, Moyà-Solà and Soria, 1981 through the description of a new and abundant fossil material from the middle Miocene localities of Toril-3, Manchones-1 and Manchones-2, Zaragoza Province, Spain. Hispanomeryx was only known by dental remains, mainly mandibles and lower teeth, and very scarce postcranial material; the fossil sample studied here includes cranial, mandibular, dental and postcranial remains, and it allows us to describe in depth, for the first time, the anatomy of the genus. We also erect the new species Hispanomeryx daamsi. The material is good and abundant enough as to include Hispanomeryx in a cladistic analysis performed to explore its phylogenetic relationships within the Pecora. This analysis includes Hispanomeryx in a monophyletic Moschidae (musk deer) composed by Micromeryx, Hispanomeryx, 'Moschus' grandeavus and extant Moschus, and recovers a clade composed by moschids and bovids; this is the first time that a Moschidae-Bovidae sister-group relationship is backed-up by morphological data. A direct sistergroup relationship between Hispanomeryx and the Bovidae is thus rejected. Several taxa previously assigned to the 'Moschidae' are rejected as true moschids. Finally, the cladistic phylogenetic analysis of Hispanomeryx demonstrates its monophyly and shows a basal species, H. aragonensis Azanza, 1986, and a clade formed by H. duriensis Morales et al., 1981 and H. daamsi sp. nov, characterized by the presence of more derived lower molars than those of H. aragonensis.

Giraffids include the only living giraffomorph ruminants and are diagnosed by the presence of bi-lobed canines and a special type of epiphyseal cranial appendages called ossicones. The family Giraffidae ranges from the latest early Miocene until today. However they are currently extant relics with only two living representatives, the African genera Okapia and Giraffa. Giraffids were much more diverse and widespread in the past, with more than 30 fossil species described. For the past decades a number of studies intended to resolve the phylogenetic relationships of the family, but due to the lack of really good cranial material no clear consensus was reached regarding the phylogenetic relationships amongst the different members of the group. The exceptionally complete remains of a new large giraffid from the late Miocene of Spain, Decennatherium rex sp. nov., allows us to improve and reassess giraffid systematics, offering a lot of new data, both anatomic and phylogenetic, on the large late Miocene giraffids of Eurasia. The results of our cladistic analysis show Decennatherium as a basal offshoot of a clade containing the gigantic samotheres and sivatheres, characterized by the presence of a Sivatherium-like ossicone-plan among other features. Decennatherium thus offers the most ancient evidence of this Sivatherium-plan and firmly establishes the early morphological patterns of evolution of a sivathere / samothere-clade that is defined as the less inclusive clade that contains Decennatherium and Sivatherium. Finally, this large group of four-ossiconed giraffids evolutionarily links Miocene Europe and Africa indicating vicariance / migration processes among the giraffid genetic pools separated by the Mediterranean Sea.

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