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Unique anatomy of lagomorph calcaneus

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The mammalian order Lagomorpha (hares, rabbits, pikas) comprises two families (Ochotonidae and Leporidae; McKenna and Bell 1998; Nowak 1999), and Recent members have a nearly world−wide distribution (Hoffman 1993; Nowak 1999). Detailed examination of the pedal morphology of extant and fossil lagomorphs revealed a unique channel (the “calcaneal canal”) running diagonally through the lagomorph calcaneus. The ancientness, ubiquity, and appearance of the calcaneal canal in all, including the earliest recognized lagomorph calcanea, and its absence from the pedes of other mammalian taxa, may indicate a long evolutionary separation of lagomorphs from other, previously suggested lagomorph relatives.
In order to provide a scale of genetic distances in the Lagomorpha, biochemical- systematic relationships among Lepus europaeus, Lepus timidus, Oryctolagus cuniculus (Leporidae) and Ochotona rufescens (Ochotonidae) were examined by hori­zontal starch gel electrophoresis of 38 isozyme systems. Nei's (1978) genetic distances were calculated over 58 presumptive structural loci and used for the construction of numerical dendrograms. The stability of clusters was examined by the jackknife method and by comparison to a Hennigian cladogram. All these procedures revealed a constant picture of lagomorph relationships, which is in accordance with the conclusions drawn from other evidence. Divergence times were estimated using two fundamentally different approaches. They were in good agreement with paleontological data (0.49myr between the Lepus species, 3.65myr between Lepus and Oryctolagus, 37.5myr between Leporidae and Ochotonidae), but only when calculated in different ways at low and at high taxonomic levels. The results suggest a temporal acceleration of the rate of allozyme evolution in the Leporidae due to rapid adaptive radiation of biochemically highly polymorphic taxa.
We describe new dental material of Eurolagus fontannesi from the Late Miocene (Early Vallesian, MN 9) lignite beds of Bełchatów A (central Poland), which is the northernmost occurrence of this lagomorph. This material considerably increases the sample size of this rare genus and species. We review the systematic position of Eurolagus and argue that it is not an ochotonid, but represents a terminal taxon of an independently evolved stem lineage of Lagomorpha. The enamel of the molars, here studied for the first time, exhibits a relatively thin decussating external and a radial internal layer, and in general resembles the palaeolagine lagomorphs (Palaeolagus) rather than the archaeolagine leporids (Hypolagus) or advanced ochotonids (Ochotona). The dental wear features of Eurolagus fontannesi indicate that the species was a sylvan mixed−feeder. This agrees with the Bełchatów A paleoenvironment, which is best approximated as the kind of mixed mesophytic forest now encountered in the Caucasus, Iran, and India. The extinction of Eurolagus was probably related to the noticeable faunal change following the increased cooling of the European climate during the Late Miocene. The first indicator of this event can be observed in Bełchatów A, marked by the immigration of Microtocricetus and the absence of Neocometes.
We report the discovery of Erenlagus anielae, a new genus and species of stem lagomorph from the lower part of the Middle Eocene Irdin Manha Formation at the Huheboerhe locality, Erlian Basin, Nei Mongol, China. The remains consist of isolated teeth; however, the material includes all loci except the incisors and P2. The new lagomorph is characterized by a small size and high degree of unilateral hypsodonty comparable to that of Aktashmys and slightly higher than that observed in the coeval and co-occurring Strenulagus. Further, it shows advanced root fusion, which exceeds even that in Gobiolagus. Although phylogenetic relationships of the Eocene lagomorphs from Asia are still not fully resolved, the dental characters of Erenlagus anielae suggest that it is most closely related to ʻLushilagusʼ danjingensis from the Middle Eocene of Henan, China and Aktashmys montealbus from the late Early Eocene of Kyrgyzstan. This stratigraphically well-constrained finding represents one of the lagomorph genera that appeared in the Eocene Glires paleobiodiversity reservoir, the Erlian Basin in Nei Mongol.
Analyses of tawny owl pellets were used to determine the species composition and distribution of small mammals in Kampinos National Park and its protection zone (central Poland). The total material collected from 58 localities contained the remains of 11,235 vertebrates (including 8,335 mammals). The study revealed 29 species of small mammals of the following orders: Soricomorpha - 4, Chiroptera - 9, Rodentia - 14, Lagomorpha - 1 and Carnivora - 1. These included two bat species of special interest (Myotis myotis and Barbastella barbastellus) listed in the 2nd Annex to the Habitats Directive of the European Union. Muscardinus avellanarius, a rodent typical of broad-leaved woodland, appeared to be relatively common and abundant in suitable habitats. Species inhabiting wet habitats, Microtus oeconomus and Neomys fodiens, were found in many localities, whereas Arvicola amphibius was rarer and less abundant. Some important refuges of small mammals were found, mostly in strictly protected areas. Although the studies conducted to date in this area likely reveal a complete list of small species of Soricomorpha and Rodentia, it is possible that 3-5 species of Chiroptera and 2 small species of Carnivora may remain to be identified.
Gongylonema neoplasticum was identified in the oesophagus of 14 wild rabbits (Oryctolagus cuniculus) from Portugal. This is the first record of Gongylonema neoplasticum in a naturally infected lagomorph species in Europe. This paper presents the most relevant measurements of adult worms and some of their surface features seen by scanning electron microscopy. Epidemiological aspects of G. neoplasticum such as geographical distribution, host spectrum and biological features are discussed.
The extinct rabbits, Hypolagus beremendensis (Kormos, 1930) and Hypolagus brachygnathus (Petényi, 1864) were the most abundant European representatives of Hypolagus (Leporidae, Archeolaginae). In Poland their fossil remains are known from rich accumulations filling karst forms of the Kraków-Wieluń Upland and Świętokrzyskie Mountains. Review of the Polish Plio-Pleistocene (Ruscinian to Biharian) material from seven localities and the description of new specimens from six localities are given. The history of research on the Central European Hypolagus is summarised and the emended differential diagnoses with synonymy are provided for each species, accompanied by descriptions of the type material. On the basis of over 11,000 specimens, the quantitative analysis (descriptive statistics and ANOVA), as well as the detailed study of tooth enamel pattern (P2 and p3 morphotype analysis) and the bone morphology were conducted, which enabled to assess the intra- and interspecific variability. H. beremendensis, the smaller and gracile species persisted from the Late Pliocene (MN 15, Węże 1 locality) to the earliest Pleistocene (Kamyk locality). In Kamyk it co-occurred with the larger, robust, and predominant H. brachygnathus, which survived in Poland until the end of the Biharian (Zalesiaki 1A locality). Palaeoecology and adaptations of both species and the possible causes of their extinction are discussed.
A multivariate analysis of 11 skull measurements, along with evaluation of the shape of maxill-premaxill suture at palatine foramina, was carried out in pikas of the alpina-hyperborea group. The study provided rational for recognition of three distinct species in this group: Ochotona alpina (Pallas, 1773), O. hyperborea (Pallas, 1811), and O. turuchanensis Naumov, 1934. O. turuchanensis is a species from central Siberia differing from O. hyperborea in the chromosome number and type of palatine foramina and from O. alpina in size of the skull. This species is allopatric with O. alpina and partly sympatric with O. hyperborea. The subspecies svatoshi is reportedly allocated to O. hyperborea. The taxonomic status of mantchurica (now allocated to hyperborea) and scorodumovi (treated at present as an isolated subspecies of O. alpina) needs careful investigation.
Hypolagus beremendensis, a representative of the Archaeolaginae, was one of the most abundant and widespread leporids in the Plio−Pleistocene of Europe. The vast accumulations of skeletal remains from the Polish Pliocene sites (Węże 1, Rębielice Królewskie 1 and 2, and Kadzielnia 1) yielded thousands of bones representing almost all skeletal regions. The detailed hind limb morphology of Hypolagus beremendensisis presented in comparison with five extant leporids (Lepus europaeus, Oryctolagus cuniculus, Pentalagus furnessi, Sylvilagus floridanus, and S. brasiliensis), which represent a wide range of locomotor adaptations. The UPGMA analysis of 98 metric characters places Hypolagus beremendensis next to the leporine rabbits. Hypolagus beremendensis has the os coxae, femur, and talus most similar to P. furnessi, tibia and calcaneus to the leporine rabbits, and the structure of foot to Lepus. The elongation of the foot and tibiofibular segment in relation to the femur indicates an advanced cursorial adaptation and a relatively steep jump. The similarities in the proximal segments (os coxae and femur) between Hypolagus and Pentalagus highlight the conservative morphology of this region in the Leporidae.
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