Članek poroča o odkritjih nahajališč pleistocenskih drobnih sesalcev v kraških zapolnitvah v Sloveniji. Najdena favna glodalcev je sestavljena iz predstavnikov arvicolidov, muridov in v manjši meri ...tudi kritecidov. V polnilu enega nahajališča pa so najdene le gliride. Določenih je šest različnih vrst lipotiplanskih insektivorov. V jamskih sedimentih so določene kosti netopirjev, ki pripadajo drugim vrstam kot žive danes v jami. The discovery of Pleistocene small mammals in karstic fillings of Slovenia is reported here. The rodent faunas collected there are mainly composed of arvicolids, murids and to a lesser degree of cricetids, although in one filling only glirids have been recorded yet. Six species of Lipotyphlan insectivores have been identified. A cave filling has yielded bats which belong to species different of those which occupy the cave to date.
A three-dimensional reconstruction of the skeleton of the giant rat of Tenerife (Canary Islands, Spain) Canariomys bravoi was obtained by computerized microtomography. Body size, body mass, and body ...shape were estimated, and limb morphofunctional indices used to infer the style of life of this recently extinct rat. A sample of recent Murinae, including the Philippines endemic giant cloud rat Phloeomys cumingi, was used for comparison. It appears that C. bravoi differed from most continental rats by its relatively large size, body proportions, and tail length. Among its distinctive features, claws almost similarly developed on fore and hind limbs, and feet longer than hands evoke an intermediate body shape between rats and arboreal murines like Phloeomys. C. bravoi was a strong and powerfully muscled rat able to move on different substrates from floor to trees, and probably had digging skills.
Une reconstitution en trois dimensions du squelette du rat géant de Tenerife (Îles Canaries, Espagne) Canariomys bravoi a été obtenue à partir d’acquisitions en microtomographie. Taille corporelle, masse corporelle, et forme du corps ont été estimées, et le style de vie fut déduit d’indices morphofonctionnels des membres. Des Murinae récents parmi lesquels Phloeomys cumingi, rat géant endémique des Philippines ont servi aux comparaisons. C. bravoi différait de la plupart des rats continentaux par sa grande taille, les proportions du corps, et la longueur de la queue. Parmi ses caractéristiques distinctives, les griffes presque d’égale importance aux membres antérieurs et postérieurs, et les pieds plus longs que les mains, évoquent une forme intermédiaire entre les rats et les vrais Murinae arboricoles comme Phloeomys. C. bravoi était un rat musclé, capable de se déplacer sur des substrats divers depuis le sol jusqu’au sommet des arbres, et capable de creuser.
Le gisement karstique de Blanquatère 1 a livré une microfaune d'âge Miocène moyen, abondante (plus de 6300 dents) et très diversifi ée en rongeurs avec 33 espèces reconnues, parmi lesquelles ...plusieurs espèces nouvelles de Cricetidae et de Gliridae. Le présent travail complète l'étude initiale par la description de Cricetidae non décrits jusqu'ici, Eumyarion, Democricetodon, Pseudofahlbuschia, des Eomyidae Ligerimys et Keramidomys et des Sciuridae Spermophilinus et Heteroxerus. Cette faune, très riche, fait de cette localité une référence pour le début du Miocène moyen (MN 4/MN 5) en Europe sud-occidentale. La faune inclut des taxons nouveaux et allochtones avec, en particulier, la présence d'un représentant des Myocricetodontinae (Dakkamys sp.), qui résulte d'une probable immigration suite à la fermeture orientale de la Téthys au cours du Langhien. C'est aussi actuellement le site le plus ancien dans lequel cohabitent Ligerimys et Keramidomys. Enfi n, cette localité souligne encore une fois l'intérêt des remplissages karstiques, susceptibles d'enregistrer des occurrences de courte durée de taxons consécutives à des événements géologiques ou climatiques. www.mnhn.fr/museum/front/medias/publication/29612_g2010n3a8.pdf
This evolution consists, first in the elaboration of the underground net systems, then in a long polyphased process of filling - emptying the karstic voids, according to the up and down base level ...changes that occurred almost continuously during the first half of the Tertiary era. The filling sediments are mostly vadose clay deposits, the various ages of which being established from the study of their fossil vertebrate contents (for latest accounts see Pelissie & Sige 2006). Then, since latest Oligocene times, the Quercy platform was covered with prograding lacustrine sediments of the Aquitaine Basin. Finally, the whole structure was strongly worn down by the so- called Plio-Pleistocene erosional phase: the previously deep underground system became closer to the surface, and was exposed both to erosion and widening, but also Plio-Pleistocene fillings occurred as shown by the fossils they include (Crochet et al. 2006). Among the latter are rare Late Pliocene and Plio-Pleistocene tooth specimens.
Malpaisomys insularis is a mouse-like rodent endemic to the eastern Canary Islands. It became extinct during the fourteenth century. It was a remarkable species living under hyperarid conditions. A ...dental microwear analysis was performed in order to determine its former diet. The elevated number of fine scratches found in Malpaisomys molars suggests that it consumed a significant part of Poaceae, grass consumption leaving the most distinctive features on dental wear facets. A graminivorous diet with a high amount of abrasive items is in agreement with the broad teeth of Malpaisomys, considered as adapted to grass consumption. However, in the absence of potential competitors over its native range, it is likely that Malpaisomys also foraged on dicots to meet higher nutrient and energetic requirements. The ecology of Malpaisomys is discussed from these results in the context of the desertic climatic conditions of the eastern Canary Islands and with a special concern on its small body size in contrast to other large-sized island murine species such as the giant rats of the central Canary Islands.
What actually is the expected pattern relating to molecular and morphological divergence? A phylogenetic correlation is expected; however, natural selection may force morphological evolution away ...from this expected correlation. To assess this relationship and the way it is modulated by selection, we investigated the radiation of the murine rodents, also called as Old World rats and mice. Regarding their diet, they are diversified as they include many omnivorous as well as specialist taxa. The size and shape of the mandible, a morphological character involved in the feeding process, was quantified and compared with an estimate of molecular divergence based on interphotoreceptor retinoid binding protein (IRBP) sequences. Size and shape of the mandible appeared to be related by an allometric relationship whatever the ecology of the taxa. Small size characterizes most murines, causing a dominance of low size distances; still, the frequency of important size differentiation increases with molecular distances. Regarding shape changes, the pattern is much contrasted between omnivores and specialists. A pattern of phenotypic drift characterizes the mandible evolution of taxa sharing an omnivorous diet. Little saturation occurs over more than 10 million years with regard to the shape of the mandible that appears as a valuable marker of phylogenetic history in this context. In contrast, important morphological distances can occur when specialist taxa are involved, even when the molecular divergence is small. Ecological specialization thus triggers an uncoupling of molecular and phenotypic evolution, and the departure from a phenotypic drift pattern.
Abstract Objective This study was designed to interpret the differences between the occlusal relationships in the murine rodents and those in their Miocene “cricetodont” ancestors. It aimed at ...understanding the functional transformations that led to the emergence of the peculiar chewing motion of the Murinae, associating forwardly directed masticatory movements to cusp interlocking, a trait unique amongst mammals. Methods Microwear analyses and simulations of occlusion achieved with size-increased 3D printings of teeth crafted from 3D data obtained by X-ray synchrotron microtomography at the European synchrotron radiation facility allow us to carefully interpret the occlusal relationships in Muroidea. Results A rotation of the direction of the chewing movements occurred from “Cricetodontinae” to Murinae. This rotation emerged without any cusp removal contrary to previous interpretations, by the way of an occlusal reorganization involving a loss of contacts between some cusps, offset by a contact with other cusps. This new organization was already present in the early and middle Miocene genus Potwarmus. Conclusion Molar tooth evolution in Murinae was characterized by the preservation and the reshaping of the primitive muroid cusps, the acquisition of supplementary cusps, and changes in the contacts between the opposite cusps. During evolution, changes of cusp patterns in upper and lower molar teeth are coordinated in order to retain a functional occlusion. Because of this functional constraint, one cusp was supposed to more likely occlude with the same opposite cusps during evolution, and therefore homologous cusps would always carry homologous attrition facets. Evolution of Murinae proves that functional continuity can also be preserved through changes in occlusal relationships independently from cusp removal.
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