A late early to early middle Eocene mammal assemblage from Bayan Ulan (Inner Mongolia,China): Implication for the reassessment of the Arshantan Asian Land Mammal Age

Paleogene mammal localities of North China are particularly well represented in the Erlian Basin, Inner Mongolia. Among them, the locality of Bayan Ulan is most famous for its late Paleocene Gashatan fauna. However, the younger Arshantan fauna of the same site is not well known, since no extensive study has been done so far. Here, we present a small mammal assemblage based on dental and tarsal material from a new Arshantan collection retrieved from the red beds of the late early to early middle Eocene Arshanto Formation at Bayan Ulan. It consists of at least six different taxa: the basal lagomorph Dawsonolagus antiquus, the large pantodont Pantolambdodon sp., the tapiroid Schlosseria magister, and the rhinocerotoids Hyrachyus crista and Rhodopagus guoi nov. sp. The assemblage is dominated by perissodactyls, especially Lophialetidae and Hyracodontidae. For the first time, p4-m1 of Dawsonolagus antiquus, tarsal material from Pantolambdodon sp., and lower dentition and tarsals of Hyrachyus crista are described and illustrated. Unlike other described Arshantan faunas, the Bayan Ulan Arshantan mammal assemblage has been collected exclusively from a single locality, which contributes to the reassessment of the misunderstood Arshantan Asian Land Mammal Age.     

Messinian Prolagus (Ochotonidae, Lagomorpha) of Italy

A systematic revision of Italian Messinian Prolagus findings has been performed, evidencing the presence of four different species. Comparative analyses allowed their separation in two groups corresponding to two different palaeobioprovinces characterized by distinct faunal affinities, source areas and tempos and modes of colonization. Such considerations allowed to cast a new light on the palaeobiogeography and the migration pathways of continental vertebrate faunas in the Mediterranean area during Messinian, and to give a new importance to the genus Prolagus as a palaeobiogeographical marker.     

Les Cases de la Valenciana,a new early Miocene small-mammal locality from the Vallès-Penedès Basin (Catalonia,Spain)

Abstract

The Valles-Penedes Basin (Catalonia, Spain) is classical area for the study of Miocene land mammal faunas. Nevertheless, the early Miocene part of the record has deserved little attention as compared to younger intervals. Most notably, the small mammals of this age have not been described in detail, consequently hampering the correlation of the Valles-Penedes record with other chronological schemes. In this work we describe the rich and diverse small mammal fauna from Les Cases de la Valenciana site (Gelida, Alt Penedès) which includes marsupials, eulipotyphlans, lagomorphs and rodents. On the basis of the presence of the cricetids Megacricetodon and Democricetodon this site is correlated with European Neogene zone MN4, yielding an age of 17–16 Ma. However, the rodent assemblage is comparable to that of chronologically close localities of the Calatayud-Montalbán Basin (Aragon, Spain), indicating that the same biochronological scheme can be applied to both areas. In this way, the coexistence of the eomyids Ligerimys ellipticus and Ligerimys florancei coupled with the presence of Megacricetodon primitivus indicates a correlation with local biozone Ca of the Calatayud-Montalban Basin, ranging from 16.3 to 16 Ma. Finally, the correlation of other early Miocene sites of the Valles-Penedes Basin is discussed and refined.     

Convergences in Scapula Morphology among Small Cursorial Mammals: An Osteological Correlate for Locomotory Specialization

Small cursorial mammals, such as lagomorphs, elephant shrews, and the more cursorial caviomorph rodents, share both the similar locomotor gait of rapid half-bounding and a similar scapula anatomy of a long, slender, caudally projecting metacromion process. This scapular morphology is also present in some notoungulates (extinct endemic South American ungulates), in rabbit-like taxa such as Propachyruchos. In the rabbit Oryctolagus this elongated metacromion process serves to increase the moment arm of the acromiotrapezius and levator scapulae ventralis muscles, which we propose may aid in scapula stabilization and resisting ground reaction forces during the landing phase onto a single forelimb in half-bounding. A long, slender metacromion process is thus an osteological correlate of locomotor specialization, that of rapid half-bounding in small to medium-sized mammals.     

Badenian and Sarmatian s.str. from the Carpathian area: Overview and ongoing research on Hungarian and Romanian small vertebrate evolution

The fossil record from the Carpathian area plays a key role for the understanding of the processes leading to the faunal interchanges between western Europe and Asia Minor during the late part of the Middle Miocene. Important mammal successions are now available from the Central Paratethys, especially Hungary and Romania. Here, we present the current state-of-the-art of the ongoing research concerning these faunas, especially small mammals and herpetofauna. We underscore the relevance of the Middle to earliest Late Miocene fossil record from these countries for chrono(bio)stratigraphic and palaeoenvironmental studies at the Eurasian scale.     

The branching order of mammuals: Phylogenetic trees inferred from nuclear and mitochrondrial molecular data

Summary In order to clarify some controverisal phylogenies such as those regarding the triplet of human, rodent, and cow and the evolutionary position of Lagompopha with respect to other mammals, we have analyzed both nuclear and mitochondrial genes using the stationary Markov model developed in our laboratory. We found that the two sets of genes give different results. In particular the mitochondrial tree showed rabbit linked first to rodents and the the rabbit-rodents branch linked to artiodactyls with human as the outgroup. The most favorite nuclear tree showed human linked first to artiocactlys and the human-artiocactyls branch linked to rabbit with rodents as the outgroup. The obvious questions, (1) which tree is the correct one, or (2) both trees can be incorrect, and (3) how can we explain such an evolutionary pattern, are discussed on the basis of our limited knowledge of factors that influence the clocklike behavior of biological macromolecules.     

Molecular Approaches Revealing Prehistoric, Historic, or Recent Translocations and Introductions of Hares (Genus Lepus) by Humans

Although only of medium size, and thus of little nutritional value compared to big game such as mammoths and ungulates, hares (Lepus spp.) probably have always been a food source for humans, as documented in archaeological finds. Nowadays, hares, particularly such species as the brown hare (L. europaeus), are among the most important game species in many European countries. For hunting, perhaps religious reasons, and in connection with certain myths, hares have been and are still being intentionally translocated. Ancient translocations by humans can be inferred from the presence of hares on islands that had no mainland connections, at least during the Pleistocene, the major evolutionary period of the genus Lepus. We review some of the literature on anthropogenic translocations of hares. We focus on three examples [the brown hare (L. europaeus), the Corsican hare (L. corsicanus), and the Sardinian hare (L. capensis)], where some molecular data could be used to trace the translocation routes and possible origins of introduced hare populations. Certain molecular marker systems, such as sequences of the hypervariable part I (HV-1) of the mitochondrial control region, show high variability in hare species and are thus promising for tracing both recent and ancient origins of translocated hares. Some other molecular marker systems as well as caveats connected with the use of such marker systems in the genus Lepus are also discussed.     

内蒙古巴彦乌兰地区始新世哺乳类及相关地层问题

记述了在内蒙古巴彦乌兰地区发现的４种始新世哺乳动物化石,其中包括１个啮齿类新种──Ｍｅｒｇｅｎｏｍｙｓ ｎｅｉｍｏｎｇｏｌｅｎｓｉｓ ｓｐ．ｎｏｖ。新种与在蒙古共和国发现的属型种Ｍ．ｏｒｉｅｎｔａｌｉｓ的不同在于个体大,下臼齿下外脊和下次小尖相对偏于唇侧。新化石的发现以及对岩石地层的分析表明巴彦乌兰剖面上原认为的伊尔丁曼哈组应包含伊尔丁曼哈及沙拉木伦组两个地层单位。     

Widespread tissue distribution of rabbit calreticulin,a non-muscle functional analogue of calsequestrin

Summary Calreticulin was identified in a variety of rabbit tissues by Western blot analysis. Indirect immunofluorescence studies on cultured cells or frozen sections from the corresponding tissues revealed that the protein was distributed to the endoplasmic reticulum or sarcoplasmic reticulum. Calreticulin was found to be an abundant calcium-binding protein in non-muscle and smooth muscle cells and a constitutent calcium-binding protein in cardiac and skeletal muscle. From the immunoblot data, calreticulin may exist as an isoform in rabbit neural retina. The present study establishes the ubiquity of calreticulin in intracellular calcium binding.     

Uveoscleral permeability to intracamerally infused ferritin in eyes of rabbits and monkeys

Summary The permeability of the uveoscleral outflow pathway from the anterior ocular chamber was examined in rabbit and monkey eyes using anionic ferritin as a tracer. Ferritin, infused intracamerally, had ready access to the choroidal interstitium, and the degree of penetration was generally correlated with the time and pressure relationships during infusion. In both species, there were accumulations of tracer in intercellular spaces at the lamina fusca, but tracer was also present in the sclera. Thus, in contrast to the situation in the eyes of hamsters, the uveoscleral outflow pathway in the eyes of rabbits and monkeys includes the choroidal connective tissue and allows passage of relatively large molecular weight substances.