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Revision of the Silesian bear fauna, based on material from 152 sites, mainly cave and karstic localities, and also archaeological and open-air sites, shows the presence of 13 forms and species. These records encompass the last 16.5 Ma and may be divided into five main morphophyletic groups. The oldest bears, represented by the genera Ballusia and Ursavus , are dated to 16.5–11 Ma, and belonged to the stem forms of the subfamily Ursinae. After a break of 6 My, the earliest members of the genus Ursus appeared, and all known Pliocene bears in Silesia belong to the genus Ursus were identified as Ursus minimus . They represent one or two migration events. Additionally, between 3.6 and 3.2 Ma, a single occurrence of Agriotherium insigne was recorded from the Weze 1 site. A few Early Pleistocene bear records are represented by U. etruscus , which was a probable ancestor of both arctoid and spelaeoid bear lineages. The oldest representative of Ursus ex gr. arctos known so far and assigned to U. a. suessenbornensis is known from one latest Early Pleistocene (1.2–0.9 Ma) locality, while other Polish records of this form require confirmation. The first occurrence of U. deningeri , the oldest taxon within the U . ex gr. deningeri–spelaeus lineage, was recorded from ~700 ka deposits in Silesia. During the pronounced cold period of MIS 12, the Scandinavian ice sheet covered almost the entire modern territory of Poland, with the exception of the Sudetes and the Carpathians. The accompanying drastic faunal turnover led to the formation of the pan-Eurasian Mammoth Fauna at ~460 ka. At that time a characteristic member of this fauna, the steppe brown bear Ursus arctos priscus , a specific ecomorph adapted to live in open grasslands, appeared in this region. It survived until the beginning of MIS 1, when modern Ursus arctos arctos appeared in Silesia and survived to the present day. U. deningeri was the most common bear during the Middle Pleistocene, while the first records of U. spelaeus spelaeus appeared since MIS 7. The latter form was replaced by U. ingressus during the Late Pleistocene (~110–100 ka). Spelaeoid bears totally dominated the cave assemblage, and finally vanished between 27 and 24 ka.

Summary In Carnivora, increases in body size often lead to dietary specialization toward hypercarnivory. Ursine bears (Tremarctos and Ursus), however, are the only omnivorous Carnivora that evolved large body sizes (i.e., >50 kg). Traits contributing to their gigantism, and how those traits evolved, have never been studied. Here we propose that special dental characters of Ursinae (parallel buccal and lingual ridges) permit a sagittally oriented mastication associated with increasing emphasis on plant foods. This pattern can be traced back to a new early diverging bear of plant-dominated omnivorous diet, Aurorarctos tirawa gen. et sp. nov. from the late Middle Miocene of North America, which was supported as the earliest known ursine bear by phylogenetic analysis. The anatomical transition to increased masticatory efficiency, probably together with the ability to hibernate, helped bears break prior ecological limitations on body size and led to the evolution of a distinctive lineage of herbivorous-omnivorous, large-bodied Carnivora., Graphical Abstract, Highlights • We describe the earliest known ursine bear, supported by phylogenetic analyses • The new fossil bear has the earliest evidence of plant-dominated omnivory diet • We discuss how traits helped ursine bears breaking energetic limitations on body size, Biological Sciences; Evolutionary Biology; Phylogenetics

Mammalian neonates are born at a wide range of maturity levels. Altricial newborns are born with limited sensory agency and require extensive parental care. In contrast, precocial neonates are relatively mature physically and often capable of independent function shortly after birth. In extant mammals, placental newborns vary from altricial to precocial, while marsupials and monotremes are all extremely altricial at birth. Bears (family Ursidae) have one of the lowest neonatal-maternal mass ratios in placental mammals, and are thought to also have the most altricial placental newborns. In particular, giant pandas (Ailuropoda melanoleuca) are thought to be exceptionally altricial at birth, and possibly marsupial-like. Here we used micro-computer (micro-computed) tomography scanning to visualize the skeletal anatomy of ursid neonates and compare their skeletal maturity with the neonates of other caniform outgroups. Specifically, we asked whether ursid neonates have exceptionally altricial skeletons at birth compared with other caniform neonates. We found that most bear neonates are similar to outgroup neonates in levels of skeletal ossification, with little variation in degree of ossification between ursine bears neonates (i.e. bears of the subfamily Ursinae). Perinatal giant pandas, however, have skeletal maturity levels most similar to a 42-45-day-old beagle fetus (~70% of total beagle gestation period). No bear exhibits the skeletal heterochronies seen in marsupial development. With regards to skeletal development, ursine bears are not exceptionally altricial relative to other caniform outgroups, but characterized largely by the drastic difference between newborn and adult body sizes. A review on the existing hypotheses for ursids' unique reproductive strategy suggests that the extremely small neonatal-maternal mass ratio of ursids may be related to the recent evolution of large adult body size, while life history characteristics retained an ancestral condition. A relatively short post-implantation gestation time may be the proximal mechanism behind the giant panda neonates' small size relative to maternal size and altricial skeletal development at birth.

Ursidae is a monophyletic group comprised of three subfamilies: Tremarctinae, Ursinae and Ailuropodinae, all of which have a rich geographical distribution. The phylogenetic relationships within the Ursidae group have been underexamined, especially regarding morphological traits such as the basicranium. Importantly, the basicranium is a highly complex region that covers a small portion of the skull, combining both structural and functional aspects that determine its morphology. Phylogenetic hypotheses of the Ursidae (including Tremarctinae) have been made based on morphological characters that considers skull, mandible and teeth features, while specific characters of the auditory region and basicranium have not been taken into account. To do this, we analyse the shape and size macroevolution of the basicranium of Ursidae, testing its morphological disparity in a phylogenetic context, which is quantified by means of the phylogenetic signal. We investigated phylogenetical autocorrelation by shape (depicted by Principal Components Analysis scores from previous published analyses) and basicranium size (depicted by centroid size, CS) using an orthonormal decomposition analysis and Abouheif C mean. The main advantages of these methods are that they rely exclusively on cladogram topology and do not require branch-length estimates. Also, an optimisation of the ancestral nodes was performed using TNT 1.5 software. In relation to the phylogenetic signal, both methods showed similar results: the presence of autocorrelation was detected in PC1 and PC2, while in PC3, PC4 and PC5 and in the size of the basicranium (CS), the absence of autocorrelation occurred. The most significant nodes (where there is autocorrelation) are the basal nodes 'Ursidae' and 'Ursinae-Tremarctinae'. Within this last group, distinctive basicranium morphology is observed, being more conservative in Tremarctinae than in Ursinae. The differences between these subfamilies could be related to historical events involving varying food and environmental preferences. The high phylogenetic signal in the node Tremarctinae probably indicates that the basicranium configuration of these bears was obtained early in their evolutionary history. Finally, our results of the basicranium and skull length ratios indicate that in Tremarctinae, the basicranium size was not determined by phylogeny but instead by other factors, such as adaptive responses to climatic changes and competition with other carnivores., Facultad de Ciencias Naturales y Museo

Panama is still far from completing its orchid flora inventories, where large genera such as Lepanthes (Pleurothallidinae) reveal novelties regularly. Here, we describe and illustrate two new species of Lepanthes. Lepanthes aures‐ursinae is similar to L. micellilabia but differs by the orbicular‐ovate, obtuse, convex leaves, larger sepals 2.7–3.0 × 2.2–2.3 mm the yellow petals, shorter column to 1 mm long and Y‐shaped bi‐laminate lip with the blades embracing the column and the body elongated towards the base of the column forming a cylindric structure. Lepanthes vertebrata is most similar to L. demissa, from which it can be distinguished by the inflorescences bearing 20–73 pedicels in well‐developed inflorescences, the vinaceous flowers, the larger lateral sepals to 6.0 × 2.3 mm, wider petals to 4.5 mm with the lower lobe longer than the blades of the lip, narrowly oblong upper lobe of petals, oblong lower lobe, shorter lip ca 1 mm long with ovate pink blades and ventral stigma. Data on distribution, habitat and ecology, etymology and phenology are provided for each species. Universidad de Costa Rica/[814-B2-161]/UCR/Costa Rica Universidad de Costa Rica/[814-B6-140]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Jardín Botánico Lankester (JBL)

The skeletal remains of a small bear (Protarctos abstrusus) were collected at the Beaver Pond fossil site in the High Arctic (Ellesmere I., Nunavut). This mid-Pliocene deposit has also yielded 12 other mammals and the remains of a boreal-forest community. Phylogenetic analysis reveals this bear to be basal to modern bears. It appears to represent an immigration event from Asia, leaving no living North American descendants. The dentition shows only modest specialization for herbivory, consistent with its basal position within Ursinae. However, the appearance of dental caries suggest a diet high in fermentable-carbohydrates. Fossil plants remains, including diverse berries, suggests that, like modern northern black bears, P. abstrusus may have exploited a high-sugar diet in the fall to promote fat accumulation and facilitate hibernation. A tendency toward a sugar-rich diet appears to have arisen early in Ursinae, and may have played a role in allowing ursine lineages to occupy cold habitats.

Members of the subfamily Ursinae dispersed into North America from Africa and Asia during the Miocene, with the appearance of Ursavus (Schlosser, 1899), Indarctos (Pilgrim, 1913), and Agriotherium (Wagner, 1837) (Dalquest, 1986; Miller and Carranza-Castan�eda, 1996; Hunt, 1998). However, none of these genera were thought to have survived past the Hemphillian Land Mammal Age in North America. It is thought that these genera were replaced, and possibly out-competed, by members of the extant genus Ursus (Linnaeus, 1758), or Plionarctos (Frick, 1926), as suggested by several sources (Bjork, 1970; Dalquest, 1986; Bell et al., 2004). It has also been suggested that the Ursavini ( Agriotherium and Indarctos ) may have given rise to the extant ursids and the Tremarctinae (Harrison, 1983; Miller and Carranza-Castan�eda, 1996). Of the Ursavini, Agriotherium is consistently found in the Hemphillian Land Mammal Age, and so is used as an index fossil in that its absence is assumed to indicate that a site is Blancan rather than Hemphillian (Lundelius et al., 1987; Bell et al., 2004; Hunt, 2004). Agriotherium is the most widely distributed member of the Ursidae, and its fossils are known from approximately 20 localities in North America, including fossil sites in Arizona, California, Florida, Kansas, Oklahoma, Nevada, Nebraska, Texas, and Mexico. These sites range from approximately 6.0 to 4.6 Ma in age and all are considered mid-late Hemphillian (Tedford et al., 2004). The latest recorded occurrence of Agriotherium from North America was ∼4.8 to 4.6 million years ago from the Yepomera Fauna, Chihuahua, Mexico (Lindsay et al., 1984; Bell et al., 2004). However, middle to late Pliocene and Pleistocene specimens are known from Poland, China, Ukraine, and South Africa. The dentary of Agriotherium described in this paper from the Hagerman Fossil Beds National Monument in Idaho is …

Evolution of the bear family Ursidae is well investigated in terms of morphological, paleontological, and genetic features. However, several phylogenetic ambiguities occur within the subfamily Ursinae (the family Ursidae excluding the giant panda and spectacled bear), which may correlate with behavioral traits of female philopatry and male-biased dispersal which form the basis of the observed matriarchal population structure in these species. In the process of bear evolution, we investigate the premise that such behavioral traits may be reflected in patterns of variation among genes with different modes of inheritance: matrilineal mitochondrial DNA (mtDNA), patrilineal Y chromosome, biparentally inherited autosomes, and the X chromosome. In the present study, we sequenced 3 Y-linked genes (3,453 bp) and 4 X-linked genes (4,960 bp) and reanalyzed previously published sequences from autosome genes (2,347 bp) in ursid species to investigate differences in evolutionary rates associated with patterns of inheritance. The results describe topological incongruence between sex-linked genes and autosome genes and between nuclear DNA and mtDNA. In more ancestral branches within the bear phylogeny, Y-linked genes evolved faster than autosome and X-linked genes, consistent with expectations based on male-driven evolution. However, this pattern changes among branches leading to each species within the lineage of Ursinae whereby the evolutionary rates of Y-linked genes have fewer than expected substitutions. This inconsistency between more recent nodes of the bear phylogeny with more ancestral nodes may reflect the influences of sex-biased dispersal as well as molecular evolutionary characteristics of the Y chromosome, and stochastic events in species natural history, and phylogeography unique to ursine bears.

A new material of Hemicyonids discovered in France, Spain and Portugal allows a new synthesis of the group, with definitions of the genera and relationships with sister-groups. The hemicyonids are shared out in three subfamilies: 1) the Phoberocyoninae enclose the genera Phoberocyon (P. hispanlcus nov. sp. of MN3a, P. dehmi , from MN3a, P. aurelianensis from MN3b, Plithocyon ( P. bruneti from MN3a; P. conquense nov. sp. from MN4, P. antunesi nov. sp. from MN, P. armagnacensis from MN5b + 6 + 7/8) and Phoberogale which is known since Upper Oligocene; 2) the Hemicyoninae which enclose Cephalogale geoffroyi, Zaragocyon from MN2, Hemicyon (H. gargan nov. sp. from the MN3a, H. stehlini from MN4b + 5, H. sansaniensis parvus from MN5b, H. sansaniensis sansaniensis from MN6, H. goeriachensis from MN6 + 7 and Dinocyon (D. thenardi) ; 3) The Ursinae with the genera Ursavus (the one of which we describe the earliest species, U. isorei nov. from MN3a), Ballusia nov. g. ( B. elmensis et B. hareni ) which yet wears many characters of Hemicyoninae and the ponto-plio-quaternary genera Indarctos, Agriotherium, Ailurarctos, Ailuropoda and Ursus .

Phylogenetic relationships of the order Carnivora have been extensively studied. However, depending on the type of data, species sampling, and method of analysis used, carnivores have been placed in nearly every possible position throughout the eutherian phylogenetic tree (for a review, see Novacek 1992). The integrity of the order itself has, however, remained intact. Undisputedly monophyletic, the order Carnivora nonetheless constitutes a very adaptable and heterogeneous group (Wayne et al. 1989) whose evolution has been marked by several events of parallel or convergent evolution and rapid radiation. Consequently, phylogenetic relationships between and within many carnivore families are also still largely unresolved. For example, the families Procyonidae, Ailuridae, Mustelidae, Pinnidedia, and Ursidae are joined at a polytomy. Within Pinnipedia, the closer affinity of Otariidae to either Phocidae or Obodenidae has long been debated. Additionally, the monophyly of the family Mustelidae has been challenged, with true mustelids and mephitids thought to belong to different branches within the superfamily Musteloidea, also including Procyonidae and Ailuridae. The phylogeny of the family Ursidae is another typical example. Six species of bears, grouped under the subfamily Ursinae, are thought to have diverged at the beginning of the Pliocene through such a rapid radiation event (Thenius 1990) that the order of species divergence is difficult to determine. Hence, the speciation event that led to extant ursine bears (American black bear, Ursus americanus; brown bear, U. arctos; polar bear, U. maritimus; Asiatic black bear, U. thibetanus; sun bear, U. malayanus; and sloth bear, U. ursinus) is usually represented as a polytomy. Rapid radiations remain unresolved largely because available data contain very few informative changes essential to infer the correct phylogenetic tree. More resolving power can be reached by using longer DNA sequences to provide a sufficient number of informative characters. Moreover, it has been shown that the combination of multiple genes in a single large data set has the potential to raise a weak phylogenetic signal above the noise level (Bull et al. 1993). Combining these two advantages, complete mitochondrial (mtDNA) sequences (approximately 17 kbp and 13 protein-coding genes) offer great potential for recovering phylogenies.

Trypsin G-banded karyotypes of eight species of Ursidae were prepared from retrovirus-transformed skin fibroblast cultures. The banding patterns of all bears are highly conserved, even though their diploid numbers range from 42 to 72. A comprehensive analysis of the homologous banding patterns within the Ursidae and with a hypothesized ancestral carnivore karyotype permitted the reconstruction of three significant chromosomal reorganization events that occurred during the evolution of the modern ursids. The first was a multichromosomal fissioning away from the biarmed (2n = 44) primitive carnivore karyotype, leading to six species of the Ursinae subfamily (2n = 78). The second was a comprehensive chromosome fusion in the lineage that led to the Ailuropodinae (giant panda) subfamily (2n = 44). The third event was a second, independent, but less extensive, centromeric fusion occurring in the line that led to the Tremarctinae (spectacled bear) subfamily (2n = 52). Ursidae karyotypes are not only highly conserved within the family but also exhibit extensive chromosome banding homology with other carnivore families.

The complete primary structure of the alpha- and beta-chains of the hemoglobin of Spectacled Bear (Tremarctos ornatus) is presented. Following cleavage of the heme-protein link and chain separation by RP-HPLC, their amino-acid sequences were determined by Edman degradation in liquid- and gas-phase sequenators. The hemoglobin of Spectacled Bear displays only five amino-acid exchanges to that of Polar Bear (Ursus maritimus, Ursinae) and Asiatic Black Bear (Ursus tibetanus, Ursinae) whereas 8 and 12 replacements, respectively, to Giant Panda (Ailuropoda melanoleuca) and Lesser Panda (Ailurus fulgens) can be found. This clearly demonstrates that the Spectacled Bear, the most aberrant bear of the Ursidae, is somewhat intermediate between Pandas and Ursinae.