Subjects -> BIOLOGY (Total: 3492 journals)
    - BIOCHEMISTRY (267 journals)
    - BIOENGINEERING (143 journals)
    - BIOLOGY (1675 journals)
    - BIOPHYSICS (50 journals)
    - BIOTECHNOLOGY (271 journals)
    - BOTANY (254 journals)
    - CYTOLOGY AND HISTOLOGY (32 journals)
    - ENTOMOLOGY (76 journals)
    - GENETICS (171 journals)
    - MICROBIOLOGY (292 journals)
    - MICROSCOPY (12 journals)
    - ORNITHOLOGY (29 journals)
    - PHYSIOLOGY (73 journals)
    - ZOOLOGY (147 journals)

BIOLOGY (1675 journals)            First | 1 2 3 4 5 6 7 8 | Last

Showing 801 - 1000 of 1720 Journals sorted alphabetically
International Journal of Peptide Research and Therapeutics     Partially Free   (Followers: 6)
International Journal of Peptides     Open Access   (Followers: 2)
International Journal of Pharmaceutical and Life Sciences     Open Access   (Followers: 5)
International Journal of Phytopathology     Open Access   (Followers: 5)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 1)
International Journal of Plant Genomics     Open Access   (Followers: 4)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Primatology     Hybrid Journal   (Followers: 7)
International Journal of Reproductive BioMedicine     Open Access   (Followers: 1)
International Journal of Scientific Reports     Open Access   (Followers: 4)
International Journal of Secondary Metabolite     Open Access   (Followers: 2)
International Journal of Signs and Semiotic Systems     Full-text available via subscription  
International Journal of Speleology     Open Access   (Followers: 3)
International Journal of Systems Biology and Biomedical Technologies     Full-text available via subscription   (Followers: 3)
International Journal of Tropical Insect Science     Hybrid Journal   (Followers: 1)
International Journal of Tryptophan Research     Open Access  
International Letters of Natural Sciences     Open Access   (Followers: 2)
International Multidisciplinary Research Journal     Open Access  
International Review of Cell and Molecular Biology     Full-text available via subscription   (Followers: 7)
International Review of Hydrobiology     Hybrid Journal   (Followers: 2)
Intervirology     Full-text available via subscription  
IntraVital     Full-text available via subscription  
Invertebrate Biology     Hybrid Journal   (Followers: 10)
Invertebrate Neuroscience     Hybrid Journal   (Followers: 4)
Invertebrate Systematics     Hybrid Journal   (Followers: 8)
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Iranian Journal of Parasitology     Open Access   (Followers: 2)
IRBM     Full-text available via subscription  
IRBM News     Full-text available via subscription  
iScience     Open Access  
Islets     Full-text available via subscription   (Followers: 1)
Israel Journal of Ecology and Evolution     Full-text available via subscription   (Followers: 1)
Istituto Lombardo - Accademia di Scienze e Lettere - Incontri di Studio     Open Access  
Italian Journal of Mycology     Open Access  
ITBM-RBM     Full-text available via subscription   (Followers: 1)
ITBM-RBM News     Full-text available via subscription   (Followers: 1)
IUBMB Life     Hybrid Journal   (Followers: 6)
IUFS Journal of Biology     Open Access  
Izvestiya, Atmospheric and Oceanic Physics     Full-text available via subscription   (Followers: 1)
Izvestiya, Physics of the Solid Earth     Hybrid Journal   (Followers: 2)
Jahangirnagar University Journal of Biological Sciences     Open Access   (Followers: 1)
Japanese Journal of Applied Physics     Full-text available via subscription   (Followers: 6)
JCI Insight     Open Access   (Followers: 3)
JDREAM : Journal of interDisciplinary REsearch Applied to Medicine     Open Access  
JETP Letters     Hybrid Journal   (Followers: 3)
JKI Datenblätter : Pflanzenkrankheiten und Diagnose     Open Access   (Followers: 2)
Jornal Interdisciplinar de Biociências     Open Access  
Journal Biastatistics : Biomedics, Industry & Business And Social Statistics     Open Access  
Journal of Bacteriology & Parasitology     Open Access   (Followers: 5)
Journal of Bioanalysis & Biomedicine     Open Access   (Followers: 1)
Journal of Bioequivalence & Bioavailability     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 4)
Journal of Computer Science & Systems Biology     Open Access   (Followers: 5)
Journal of Proteomics & Bioinformatics     Open Access   (Followers: 10)
Journal of Advanced Laboratory Research in Biology     Open Access   (Followers: 1)
Journal of Advances in Biology     Open Access   (Followers: 5)
Journal of Advances in Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Agricultural, Biological & Environmental Statistics     Hybrid Journal   (Followers: 11)
Journal of Al-Qadisiyah for Pure Science     Open Access   (Followers: 1)
Journal of Amino Acids     Open Access   (Followers: 4)
Journal of Anatomy     Hybrid Journal   (Followers: 7)
Journal of AOAC International     Full-text available via subscription   (Followers: 8)
Journal of Applied Biobehavioral Research     Hybrid Journal  
Journal of Applied Bioinformatics & Computational Biology     Hybrid Journal   (Followers: 5)
Journal of Applied Biological Sciences     Open Access   (Followers: 2)
Journal of Applied Biosciences     Open Access   (Followers: 2)
Journal of Applied Ichthyology     Hybrid Journal   (Followers: 6)
Journal of Applied Life Sciences International     Open Access   (Followers: 1)
Journal of Applied Phycology     Hybrid Journal   (Followers: 10)
Journal of Applied Virology     Open Access   (Followers: 5)
Journal of Aquatic Sciences     Full-text available via subscription   (Followers: 3)
Journal of Arachnology     Full-text available via subscription  
Journal of Asia-Pacific Biodiversity     Open Access  
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Avian Biology     Hybrid Journal   (Followers: 24)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Bio-Science     Open Access   (Followers: 3)
Journal of Bio-X Research     Open Access   (Followers: 1)
Journal of Biobased Materials and Bioenergy     Full-text available via subscription  
Journal of Biocommunication     Open Access   (Followers: 2)
Journal of Biodiversity Management & Forestry     Hybrid Journal   (Followers: 6)
Journal of Bioenergetics and Biomembranes     Hybrid Journal   (Followers: 1)
Journal of Biogeography     Hybrid Journal   (Followers: 45)
Journal of Bioinformatics and Computational Biology     Hybrid Journal   (Followers: 19)
Journal of Bioinformatics and Intelligent Control     Full-text available via subscription   (Followers: 2)
Journal of Bioinformatics and Sequence Analysis     Open Access   (Followers: 1)
Journal of Biological Control     Hybrid Journal   (Followers: 2)
Journal of Biological Dynamics     Open Access   (Followers: 1)
Journal of Biological Education     Hybrid Journal   (Followers: 2)
Journal of Biological Engineering     Open Access   (Followers: 3)
Journal of Biological Methods     Open Access  
Journal of Biological Physics     Hybrid Journal   (Followers: 1)
Journal of Biological Research - Thessaloniki     Open Access  
Journal of Biological Sciences     Open Access   (Followers: 5)
Journal of Biological Systems     Hybrid Journal   (Followers: 2)
Journal of Biology and Life Science     Open Access   (Followers: 2)
Journal of Biology, Agriculture and Healthcare     Open Access   (Followers: 11)
Journal of Biomechanics     Hybrid Journal   (Followers: 42)
Journal of Biomedical Education     Open Access   (Followers: 2)
Journal of Biomedical Informatics     Partially Free   (Followers: 16)
Journal of Biomedical Informatics : X     Open Access  
Journal of Biomedical Materials Research Part A     Hybrid Journal   (Followers: 3)
Journal of Biomedical Materials Research Part B : Applied Biomaterials     Hybrid Journal   (Followers: 2)
Journal of Biomedical Nanotechnology     Full-text available via subscription   (Followers: 3)
Journal of Biomedical Physics and Engineering     Open Access  
Journal of Biomedical Science and Engineering     Open Access   (Followers: 2)
Journal of Bionic Engineering     Hybrid Journal  
Journal of Bioresource Management     Open Access  
Journal of Biorheology     Hybrid Journal  
Journal of Biosafety and Biosecurity     Open Access  
Journal of Bioscience and Bioengineering     Full-text available via subscription   (Followers: 31)
Journal of Biosciences and Medicines     Open Access   (Followers: 3)
Journal of Biosocial Science     Hybrid Journal   (Followers: 5)
Journal of Bryology     Hybrid Journal   (Followers: 7)
Journal of Cell Biology     Full-text available via subscription   (Followers: 49)
Journal of Cell Communication and Signaling     Hybrid Journal  
Journal of Cell Death     Open Access   (Followers: 2)
Journal of Cell Science     Full-text available via subscription   (Followers: 18)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 4)
Journal of Cellular Physiology     Hybrid Journal   (Followers: 7)
Journal of Cerebral Blood Flow & Metabolism     Hybrid Journal   (Followers: 2)
Journal of Chromatography B     Hybrid Journal   (Followers: 35)
Journal of Clinical Bioinformatics     Open Access   (Followers: 5)
Journal of Clinical Toxicology     Open Access   (Followers: 6)
Journal of Communications Technology and Electronics     Hybrid Journal   (Followers: 2)
Journal of Contemporary Physics (Armenian Academy of Sciences)     Hybrid Journal   (Followers: 10)
Journal of Crustacean Biology     Hybrid Journal   (Followers: 3)
Journal of Developmental Biology     Open Access   (Followers: 2)
Journal of Ecology and The Natural Environment     Open Access   (Followers: 4)
Journal of Education, Health and Sport     Open Access   (Followers: 4)
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electromyography and Kinesiology     Hybrid Journal   (Followers: 5)
Journal of Environment and Ecology     Open Access   (Followers: 10)
Journal of Environment and Sociobiology     Hybrid Journal   (Followers: 1)
Journal of Environmental Analysis and Progress     Open Access  
Journal of Environmental Radioactivity     Hybrid Journal   (Followers: 3)
Journal of Environmental Science and Natural Resources     Open Access   (Followers: 4)
Journal of Ethnobiology     Full-text available via subscription   (Followers: 4)
Journal of Ethnobiology and Ethnomedicine     Open Access  
Journal of Ethology     Hybrid Journal   (Followers: 3)
Journal of Evolutionary Biology     Hybrid Journal   (Followers: 26)
Journal of Evolutionary Biology Research     Open Access  
Journal of Experimental and Clinical Anatomy     Open Access   (Followers: 2)
Journal of Experimental Life Science     Open Access  
Journal of Experimental Marine Biology and Ecology     Hybrid Journal   (Followers: 41)
Journal of Fish Biology     Hybrid Journal   (Followers: 36)
Journal of Functional Biomaterials     Open Access   (Followers: 3)
Journal of Fungi     Open Access   (Followers: 3)
Journal of Genomics     Open Access   (Followers: 1)
Journal of Great Lakes Research     Hybrid Journal   (Followers: 7)
Journal of Green Science and Technology     Full-text available via subscription   (Followers: 2)
Journal of Health and Biological Sciences     Open Access   (Followers: 1)
Journal of Heredity     Hybrid Journal   (Followers: 4)
Journal of Huazhong University of Science and Technology [Medical Sciences]     Hybrid Journal  
Journal of Human Evolution     Hybrid Journal   (Followers: 18)
Journal of Hymenoptera Research     Open Access   (Followers: 3)
Journal of Ichthyology     Full-text available via subscription   (Followers: 3)
Journal of Insect Behavior     Hybrid Journal   (Followers: 7)
Journal of Insect Biodiversity     Open Access   (Followers: 4)
Journal of Insect Conservation     Hybrid Journal   (Followers: 11)
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated OMICS     Open Access  
Journal of Integrated Pest Management     Open Access   (Followers: 3)
Journal of Integrative Environmental Sciences     Hybrid Journal   (Followers: 4)
Journal of Intelligent Transportation Systems: Technology, Planning, and Operations     Hybrid Journal   (Followers: 4)
Journal of Invertebrate Pathology     Hybrid Journal   (Followers: 3)
Journal of Kerbala University     Open Access   (Followers: 1)
Journal of Landscape Ecology     Open Access   (Followers: 20)
Journal of Law and the Biosciences     Open Access   (Followers: 5)
Journal of Leukocyte Biology     Open Access   (Followers: 2)
Journal of Life and Earth Science     Open Access  
Journal of Life Sciences Research     Open Access  
Journal of Lipid Research     Full-text available via subscription   (Followers: 6)
Journal of Lipids     Open Access  
Journal of Luminescence     Hybrid Journal   (Followers: 5)
Journal of Mammalian Evolution     Hybrid Journal   (Followers: 7)
Journal of Mammalian Ova Research     Full-text available via subscription  
Journal of Mammalogy     Full-text available via subscription   (Followers: 16)
Journal of Mammary Gland Biology and Neoplasia     Hybrid Journal   (Followers: 1)
Journal of Marine and Aquatic Sciences     Open Access   (Followers: 1)
Journal of Marine Sciences     Open Access   (Followers: 17)
Journal of Mathematical Biology     Hybrid Journal   (Followers: 8)
Journal of Mechanics in Medicine and Biology     Hybrid Journal  
Journal of Medical Primatology     Hybrid Journal   (Followers: 1)
Journal of Medical Toxicology     Hybrid Journal   (Followers: 6)
Journal of Medicinal Botany     Open Access  
Journal of Medicine and Philosophy     Hybrid Journal   (Followers: 8)
Journal of Melittology     Open Access   (Followers: 1)
Journal of Membrane Biology     Hybrid Journal   (Followers: 1)
Journal of Membrane Computing     Hybrid Journal  
Journal of Membrane Science     Hybrid Journal   (Followers: 25)
Journal of Metabolomics & Systems Biology     Open Access   (Followers: 2)
Journal of Molecular Biology     Hybrid Journal   (Followers: 45)
Journal of Molecular Biology Research     Open Access   (Followers: 3)
Journal of Molecular Catalysis B: Enzymatic     Hybrid Journal   (Followers: 1)
Journal of Molecular Cell Biology     Hybrid Journal   (Followers: 14)
Journal of Molecular Evolution     Hybrid Journal   (Followers: 6)
Journal of Molecular Signaling     Open Access  
Journal of Molecular Structure     Hybrid Journal   (Followers: 7)

  First | 1 2 3 4 5 6 7 8 | Last

Similar Journals
Journal Cover
Journal of Mammalian Evolution
Journal Prestige (SJR): 1.19
Citation Impact (citeScore): 2
Number of Followers: 7  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1573-7055 - ISSN (Online) 1064-7554
Published by Springer-Verlag Homepage  [2626 journals]
  • Correlated Evolution of White Spots on Ears and Closed Habitat Preferences
           in Felids
    • Abstract: Abstract The pigmentation patterns of many carnivorous mammals comprise contrasting white patches of hair in different parts of the body whose evolution remains largely misunderstood. Some felids (Felidae) exhibit conspicuous white spots on the posterior part of the ears, while the ear color of others is uniform. On the basis that ear movement in felids has a role in intraspecific communication and that color contrast enhances detection, here it is hypothesized that white spots on ears may be particularly adaptive under conditions of poor visibility and thus be associated with the occupancy of closed habitats. This prediction was tested using phylogenetic logistic regression models with all species of extant felids. Results show a clear association between the occurrence of white spots on ears and preference for closed habitats, and this is independent of body size and whether species that occupy both closed and open habitats are considered as closed- or open-habitat specialists. Phylogenetic signal analyses indicate that the occurrence of white spots on ears is a highly conserved trait while habitat preferences are evolutionarily labile, suggesting that the presence of white spots may have partly contributed to the adaptation of felids to closed habitats. These findings indicate that some subtle pigment traits have fulfilled a significant role in determining the success of habitat occupancy by felids and possibly other mammals, which in turn has driven the evolutionary maintenance of such traits.
      PubDate: 2019-03-16
       
  • Evolutionary and Functional Implications of Incisor Enamel Microstructure
           Diversity in Notoungulata (Placentalia, Mammalia)
    • Abstract: Abstract Notoungulates are an extinct clade of South American mammals, comprising a large diversity of body sizes and skeletal morphologies, and including taxa with highly specialized dentitions. The evolutionary history of notoungulates is characterized by numerous dental convergences, such as continuous growth of both molars and incisors, which repeatedly occurred in late-diverging families to counter the effects of abrasion. The main goal of this study is to determine if the acquisition of high-crowned incisors in different notoungulate families was accompanied by significant and repeated changes in their enamel microstructure. More generally, it aims at identifying evolutionary patterns of incisor enamel microstructure in notoungulates. Fifty-eight samples of incisors encompassing 21 genera of notoungulates were sectioned to study the enamel microstructure using a scanning electron microscope. We showed that most Eocene taxa were characterized by an incisor schmelzmuster involving only radial enamel. Interestingly, derived schmelzmusters involving the presence of Hunter-Schreger bands (HSB) and of modified radial enamel occurred in all four late-diverging families, mostly in parallel with morphological specializations, such as crown height increase. Despite a high degree of homoplasy, some characters detected at different levels of enamel complexity (e.g., labial versus lingual sides, upper versus lower incisors) might also be useful for phylogenetic reconstructions. Comparisons with perissodactyls showed that notoungulates paralleled equids in some aspects related to abrasion resistance, in having evolved transverse to oblique HSB combined with modified radial enamel and high-crowned incisors.
      PubDate: 2019-03-13
       
  • Commonality in Pelvic Anatomy among Three Fossorial, Scratch-Digging,
           Mammalian Species
    • Abstract: Abstract This study tests whether three species of fossorial, scratch-digging mammals – Dasypus novemcinctus, Ictidomys tridecemlineatus, and Taxidea taxus – show commonality in pelvic anatomies inferred to be adaptive for this behavior and, correspondingly, divergence in these anatomies from nonfossorial species. The fossorial and nonfossorial species are in the same superorder or family; the comparative sets of species are D. novemcinctus with Bradypus variegatus and Choloepus hoffmanni, I. tridecemlineatus with Sciurus carolinensis, and Ta. taxus with Gulo gulo, Martes americana, and Neovison vison. Fossorial species are hypothesized to show higher prevalence of fusion of sacroiliac and sacroischial (if present) joints, reduction in size or loss of pelvic symphysis, greater number of sacral vertebrae, greater number of vertebrae in articulation with ilium and ischium, and longer ischium. Only males were used in the study; total sample size was 318 adults and 135 subadults. Results show commonality among fossorial species in greater number of sacral vertebrae and rigidity of the pelvis. One inconsistency with expectations is that the pelvic symphysis in fossorial species is as sturdy as in nonfossorial species, based on prevalence of symphyseal fusion and relative length and breadth of pelvic symphysis. Greater number of sacral vertebrae may be due to assimilation of a lumbar vertebra(−e) with the sacrum in fossorial species associated with their slow running speed. A rigid pelvis, due to fusion of pelvic joints and relatively longer or broader pelvic symphysis, effectively transfers forces between vertebral column and hind limb.
      PubDate: 2019-03-08
       
  • Into Landscapes of Fear: Marsupial Predators
    • PubDate: 2019-03-05
       
  • Phylogenetic and Morphological Analysis of Birch Mice (Genus Sicista ,
           Family Sminthidae, Rodentia) in the Kazak Cradle with Description of a New
           Species
    • Abstract: Abstract Birch mice (genus Sicista) represent an early diverging lineage of dipodid rodents with a wide geographic distribution and a cryptic lifestyle that makes the genus difficult to study. As a result, reconstructing the evolutionary phylogeny of the group remains incomplete. Here, we report the molecular phylogeny of the genus based on mitochondrial and nuclear markers sampled from 12 of the 14 known living species. Moreover, we discuss morphological character (i.e., fur coloration and glans penis morphology) evolution in the genus. We have found a strong agreement between phylogenetic relationships among species and morphological peculiarities, both supporting a mountainous origin of Sicista, and a recent spread towards lowlands of some lineages. Glans penis structure turned out to be rather simple in the early lineages, but became more complex in phylogenetically later diverging taxa. The presence of dorsal stripes is associated with the colonization of lowland habitats. In addition, we describe here a species new to science from the Tien Shan Mountains, and provide evidence of uncovered cryptic diversity from the region. Additionally, we revise the identification of a specimen collected from China, thus documenting the presence of Sicista pseudonapaea, previously unreported from that country.
      PubDate: 2019-03-01
       
  • Virtual Endocast Morphology of Mesotheriidae (Mammalia, Notoungulata,
           Typotheria): New Insights and Implications on Notoungulate Encephalization
           and Brain Evolution
    • Abstract: Abstract We provide morphological, quantitative, and qualitative studies of cranial endocasts of mesotheriid notoungulates solving previous open debate on notoungulate endocasts. For that purpose, we use the most accurate digital reconstructions methods. We confirm that mesotheriids have endocasts similar in shape and gyrification to those of other rodent-like notoungulates (i.e., Hegetotheriidae and Interatheriidae) and living cavy rodents (e.g., Dolicavia minuscula, Hydrochoerus, and Cavia). We identify these similarities as evolutionary response to potentially similar ecological constraints. Based on the encephalization quotient (EQ) of several notoungulate families (i.e., Mesotheriidae, Interatheriidae, Notohippidae, Toxodontiidae, and Hegetotheriidae), there seems to be no increase in terms of EQ or neocortical complexity through time in that group. In addition, comparison with several Holarctic ‘euungulates’ leads us to propose differential predation pressure as a potential driver for EQ. Among notoungulates, braincase comparison between well-known Oligocene–Pleistocene mesotheriids and other families identifies lifestyle as an additional possible driver for EQ, with lower values for semifossorial taxa, in a similar way to rodents. Finally, the observed stability of mesotheriid EQ (from the Oligocene to the Pliocene) would match a conservative lifestyle further reflected by their highly invariant appendicular skeleton.
      PubDate: 2019-03-01
       
  • Absence of Relationship between Mitochondrial DNA Evolutionary Rate and
           Longevity in Mammals except for CYTB
    • Abstract: Abstract On the relationship between mitochondrion and longevity in mammals, two viewpoints have been proposed: one found that the amino acid substitution rates of most of the mitochondrial DNA-coding peptides were positively correlated with longevity, while the other raised the opposite view. To resolve this dichotomy, and to explore the relationship between mtDNA evolution and longevity in mammals, we examined this relationship in 85 mammal species, at the nucleotide sequence level. Previous studies have demonstrated that phylogenetic inertia, substitution saturation, and body mass can affect the relationship between longevity and substitution rate. Therefore, analyses should take these factors into account. This study found that after controlling the aforementioned factors, no significant positive or negative relationship existed between mitochondrial DNA evolutionary rate and longevity except for CYTB, partly agreeing with a previous study. Variations of longevity can be explained partly by the evolutionary rate of CYTB, but other influencing factors still need to be studied in the future.
      PubDate: 2019-03-01
       
  • Functional and Systematic Implications of the Postcranial Anatomy of a
           Late Miocene Feline (Carnivora, Felidae) from Batallones-1 (Madrid, Spain)
           
    • Abstract: Abstract The Spanish late Miocene locality of Batallones-1 yielded a rich sample of large carnivorans, including saber-toothed felids, amphicyonids, and ailurids, but also of smaller species, with the small cats being especially interesting. Two species are known from Batallones-1, one of them the size of a wildcat, Felis silvestris, the other one the size of a caracal, Caracal caracal. The former is represented by skulls, mandibles, and postcranial bones, whereas the latter is known from a collection of long bones. Both species are less abundant than their larger relatives, the saber-toothed felids Promegantereon ogygia and Machairodus aphanistus, but the available sample allows us to assess body proportions and adaptations of the smallest species, and to propose a new genus for this feline, Leptofelis vallesiensis. Its limb bones are remarkably gracile compared to fossils of the earlier genera Pseudaelurus, Miopanthera, and Styriofelis, and comparable in cursorial adaptations to the wildcat, very different from extant arboreal cats. While middle Miocene felids were likely semi-arboreal forest dwellers, L. vallesiensis would be mostly terrestrial, climbing essentially for protection. This indicates an adaptation to a mosaic of habitats, including relatively open terrain, and may be related to the climatic changes detected in Eurasia during the late Miocene.
      PubDate: 2019-03-01
       
  • Elbow Joint Geometry in Bears (Ursidae, Carnivora): a Tool to Infer
           Paleobiology and Functional Adaptations of Quaternary Fossils
    • Abstract: Abstract Bears are currently represented by eight species among Carnivora. Being all particularly large and generally plantigrade limits to certain extent their functional morphology so that inferences about their past diversification are difficult to achieve. We analyzed variation in bears’ elbow joint size and shape to reconstruct paleobiology of Quaternary fossil species. By using 2D geometric morphometrics, we were able to discriminate with high degree of accuracy species, locomotor and habitat adaptations among extant bears. The giant panda and the spectacled bear are well characterized by an enlarged medial epicondyle, while large members of the genus Ursus can be distinguished by their relatively longer and wider trochlea. Elbow joint size varies consistently among ecological categories of extant bears and is generally selected by discriminant function models providing a high degree of classification accuracy (> 80%). American genera Arctotherium and Arctodus are predicted as non-climbing species potentially adapted to open and mixed environments in agreement with their potentially opportunistic feeding behavior. They retain a wide medial epicondyle probably in relation to a high degree of forelimb dexterity. Cave bears are equally predicted as non-climbers adapted to open habitats while the middle Pleistocene Ursus deningeri and fossil Ursus arctos are generally classified as scansorial species with a preference towards mixed habitats. Our study is the first to demonstrate that fragmentary distal epiphyses also can be useful for interpreting functional morphology and ecological adaptations within the family Ursidae.
      PubDate: 2019-03-01
       
  • The Palmar and Plantar Anatomy of Dromiciops gliroides Thomas, 1894
           (Marsupialia, Microbiotheria) and its Relationship to Australian
           Marsupials
    • Abstract: Abstract The monito del monte Dromiciops gliroides Thomas, 1894, is a marsupial endemic to the temperate rainforests of Argentina and Chile. Studies on its phylogenetic relationships show the species is more closely related to Australian marsupials than to any other American taxon. The study of the palmar and plantar anatomy in this species through direct observation of more than 86 specimens and comparisons with American and Australian marsupials show the pattern of D. gliroides is derived from the ancestral mammalian pattern. Dromiciops gliroides show the presence of a single palmar/plantar pad in the position of interdigital pad 1 and the lack of a thenar pad (or the complete fusion between both pads), a pattern that appears closer to some Australian diprotodont marsupials. Also shared with several Australian marsupials is the transverse orientation of pad ridges, a condition that is not shared with most arboreal/scansorial American marsupials (e.g., Caluromys spp., Marmosa spp., Marmosops spp.).
      PubDate: 2019-03-01
       
  • Demographic Parameters of the Silky Shrew-Opossum Caenolestes fuliginosus
           (Paucituberculata, Caenolestidae) along an Altitudinal Gradient in the
           Cordillera Central of the Colombian Andes
    • Abstract: Abstract The order Paucituberculata is poorly studied in comparison to other marsupial orders. This order has been of interest in evolutionary research because it shows unique characteristics within marsupials (e.g., morphology and anatomy). Caenolestes fuliginosus is the most studied and better represented species in mammalian collections. However, there is limited information regarding its ecology and even less data on population parameters. This study aims to describe some of the population parameters (i.e., sex and age ratios within an altitudinal gradient), providing information about sexual dimorphism and reproduction of this species. This research was conducted in Risaralda, Caldas, and Tolima departments in Colombia, between March and October 2014. The sampling effort was 9180 trap/nights. Sherman and pitfall traps with two types of bait used. During the study, 52 individuals were captured, consisting of 31 males and 19 females. Our results suggest that populations of this species have a male-biased sex ratio, and this bias remains consistent along the altitudinal gradient of its range. We report sexual dimorphism in C. fuliginosus with significant differences in canine shape and size and in body weight between male and female individuals. Finally, we suggest that the method used in this study should be applied in future studies of C. fuliginosus due to its effectiveness.
      PubDate: 2019-03-01
       
  • Internal Morphology of Osteoderms of Extinct Armadillos and Its
           Relationship with Environmental Conditions
    • Abstract: Abstract The most complete and continuous fossil record of armadillos is composed mostly by isolated osteoderms, frequently found in paleontological and archaeological sites that bear continental South American mammals. Their external morphology has been used to define several species. In the last decade, many authors have focused on the internal structure of vertebrate osteoderms using histological and paleohistological studies. These studies allowed identification of useful features in systematic and phylogenetic contexts. In armadillos, osteoderms are constituted by compact bone tissue (primary and secondary osteons, and concentric layers or lamellae) that delimits cavities, which could contain different soft tissues (adipose tissue, hair follicles, bone marrow, and sweat and sebaceous glands). Traditional paleohistological techniques have allowed the recognition of homologous cavities to those found in osteoderms of current species and from comparison deduce which kind of tissue could had occupied them. We have recently utilized 3D reconstructions in osteoderms of extant species of armadillos to analyze the micromorphology, disposition, and the relationship of different cavities and understand them in depth. Here, we present the results of the application of paleohistology and microtomography in osteoderms of representatives of diferent taxa of extinct Dasypodidae (Astegotheriini, Stegotheriini, “Utaetini,” Euphractini, Eutatini), which allowed us to compare homologous structures based on their three-dimensional reconstruction. The results, added to the previous external morphology studies, have allowed us to define morphological patterns (consistent within each linage). The variation of the volume and extension of cavities associated with different tissues could be strongly associated with changes in the climate and environmental conditions of the species distribution areas.
      PubDate: 2019-03-01
       
  • Using Paleoclimate and the Fossil Record to Explain Past and Present
           Distributions of Armadillos (Xenarthra, Dasypodidae)
    • Abstract: Abstract Numerous climatic fluctuations occurred during the Cenozoic (last 66 Ma BP); some of them were drastic (e.g., during the Eocene-Oligocene boundary) while others were more gradual (e.g., late Tertiary cooling), but both have deep effect on the biotas. Armadillos are exclusively from the Americas; they have an old evolutionary history in South America and faunal replacement and/or local extinctions were detected, linked with climatic fluctuations. The global cooling of the late Eocene - early Oligocene coincides with a well-documented faunal turnover of Dasypodinae by Euphractinae in Patagonia. During cold and arid periods of the Quaternary, Euphractinae and Tolypeutinae moved more than once to the eastern Pampean Region, and Dasypodinae moved northward to central Brazil or even further north to the Guyana Region. During interglacial periods some armadillos went extinct locally and/or moved to Patagonia (Zaedyus), central Argentina (Tolypeutes matacus, Chaetophractus vellerosus), or from the north to Mesopotamia and the Pampean Region (Dasypus). Since the end of the Pleistocene/early Holocene, human activity has strongly impacted armadillo populations. Currently, the eastern Pampean Region (Argentina) is characterized by the presence of the couple C. villosus - D. hybridus (probably established since the late Holocene), but during the Pleistocene was Z. pichiy – T. matacus while Z. pichiy - C. villosus characterized early-middle Holocene. This work serves as evidence that paleozoological studies can be used to assess responses of biological systems to large scale perturbations and is the basis for studying future species distributions, in order to identify species in danger of extinction and establish management actions.
      PubDate: 2019-03-01
       
  • Re-examination of the Jurassic Mammaliaform Docodon victor by Computed
           Tomography and Occlusal Functional Analysis
    • Abstract: Abstract Docodon was the first described docodont, and has long featured prominently in the comparative and functional morphology of mammaliaform mandibles and teeth. We have now re-examined the dental and mandibular fossils of Docodon from Yale Quarry 9 at the Como Bluff site in the Late Jurassic Morrison Formation, using Computed Tomography (CT) scans and 3D image analyses. Our CT study revealed that some features used to distinguish the several Docodon “species” in historical studies many decades ago were based on incorrect manual restoration of mandibles, and on variable features of deciduous premolars, which are replaced in typical mammaliaform fashion. This supports a long-held notion that the multiple species of Docodon from the same quarry of the Morrison Formation are over-split and should be synonymized. We formally propose that the specimens examined in this study be synonymized under Docodon victor. Our new Occlusal Fingerprint Analysis (OFA) of Docodon molars supports the hypothesis that Docodon had a consistent dorso-posterior or palinal component in chewing in the disto-distolingual to distolingual direction. This helps to resolve the controversial historical alternative hypotheses postulated for tooth occlusion in the taxon. The Docodon occlusal pattern is likely a derived feature, evolved within Docodonta. A posterior component in the occlusal trajectory is a functional convergence of Docodon on unrelated traversodontid cynodonts.
      PubDate: 2019-03-01
       
  • Modern Tapirs as Morphofunctional Analogues for Locomotion in Endemic
           Eocene European Perissodactyls
    • Abstract: Abstract Tapirs have historically been considered as ecologically analogous to several groups of extinct perissodactyls based on dental and locomotor morphology. Here, we investigate comparative functional morphology between living tapirs and endemic Eocene European perissodactyls to ascertain whether tapirs represent viable analogues for locomotion in palaeotheres and lophiodontids. Forelimb bones from 20 species of Eocene European perissodactyls were laser scanned and compared to a forelimb dataset of extant Tapirus. Bone shape was quantified using 3D geometric morphometrics; coordinates were Procrustes aligned and compared using Principal Component Analysis and neighbor-joining trees. Functional traits included lever-arm ratios (LARs; proxy for joint angular velocity), long-bone proportions (speed proxy), and estimated body mass. Results suggest that Paralophiodon and Palaeotherium magnum resemble Neotropical tapirs in humeral morphology and LARs. Palaeotheres demonstrate extensive forelimb shape disparity. Despite previous assessments, metacarpal shape analyzes do not support a strong morphological similarity between palaeotheres and tapirs, with Tapirus pinchaque representing the closest analogue for Eocene European equoid manus morphology. Our analyses suggest lophiodontids were not capable of moving as swiftly as tapirs due to greater loading over the manus. We conclude that the variation within modern tapir forelimb morphology confounds the assignment of one living analogue within Tapirus for extinct European equoids, whereas tapirs adapted for greater loading over the manus (e.g., T. bairdii, T. indicus) represent viable locomotor analogues for lophiodontids. This study represents a valuable first step toward locomotor simulation and behavioral inference for both hippomorph and tapiromorph perissodactyls in Eocene faunal communities.
      PubDate: 2019-02-18
       
  • Evolution of Appendicular Specializations for Fossoriality in
           Euryzygomatomyine Spiny Rats across Different Brazilian Biomes
           (Echimyidae, Hystricognathi, Rodentia)
    • Abstract: Abstract The evolution of subterranean and fossorial rodents has been linked to the Neogene climatic shift to xeric conditions leading to open vegetation, like prairies and grasslands; most modern subterranean rodents occur in arid and open areas. Among South American spiny rats (family Echimyidae), the subfamily Euryzygomatomyinae includes both fossorial (Clyomys and Euryzygomatomys) and ambulatorial (Trinomys) genera, some of them endemic to open vegetated areas and other ones restricted to forested regions. The closely related genus Carterodon is also a fossorial rodent endemic to open vegetated areas. If the open environments constitute a determinant factor triggering the evolution of fossoriality in these spiny rats, it is expected that the fossorial lineages evolving since the Miocene in open environments (Carterodon sulcidens and Clyomys laticeps) show morphologies more specialized for digging than those currently restricted to Atlantic Forest habitats (Euryzygomatomys spinosus). Moreover, it is likely that Trinomys species specialized for xeric environments (T. albispinus and T. yonenagae) show incipient adaptations for fossoriality. The appendicular skeleton of three fossorial and five ambulatorial echimyid species were morphometrically analyzed with multivariate statistical approaches in order to test these presuppositions. The analyses showed that the appendicular morphology of T. yonenagae and T. albispinus, in comparison with the Atlantic Forest Trinomys species, and of C. sulcidens and C. laticeps in relation to E. spinosus are more adapted to scratch-digging activities, corroborating the hypothesis that open environments favor the evolution of fossoriality in spiny rats.
      PubDate: 2019-02-06
       
  • Brain and Behavior of Dromiciops gliroides
    • Abstract: Abstract We have analyzed the internal structure of the brain of the microbiotherian marsupial Dromiciops gliroides and compared it with the brains of American and Australian marsupials. Dromiciops does not have a fasciculus aberrans, but does exhibit other features of brain structure that are similar to diprotodontid metatherians (e.g., lamination of the lateral geniculate nucleus of the dorsal thalamus). Cortical organization in Dromiciops shows some similarities with that in Australian marsupial carnivores in that the proportional areas of isocortex devoted to somatosensory and visual function are similar in size to each other, and greater in area than that devoted to olfactory or auditory function. This points to similar sensory requirements for the foraging lifestyle of Dromiciops and small Australian marsupial carnivores, with isocortical specialization for somatosensation and vision. We also examined phylogenetic relationships of Dromiciops with extant marsupials based on maximum parsimony analysis using a soft body brain morphology-only matrix, representing 93 extant marsupial taxa. The results recovered Dromiciops as a sister group to the Australasian marsupial clade Diprotodontia.
      PubDate: 2019-01-21
       
  • Enamel Microstructure in Eocene Cetaceans from Antarctica (Archaeoceti and
           Mysticeti)
    • Abstract: Abstract Modern baleen whales have no adult teeth, whereas dolphins and porpoises have a homodont and polydont dentition, with simplified enamel microstructure. However, archaic cetaceans (archaeocetes and early mysticetes and odontocetes) had a complex and ornamented dentition, with complex enamel microstructure as in terrestrial mammals. This study describes the morphology of teeth and enamel microstructure in two fossil cetaceans from Antarctica: a basilosaurid archaeocete from the La Meseta Formation (middle Eocene); and Llanocetus sp. from the Submeseta Formation (late Eocene), one of the oldest mysticetes known. The two teeth analyzed were lower premolars, with transversely compressed triangular crowns composed of a main cusp and accessory denticles. The enamel microstructure of the basilosaurid and Llanocetus sp. is prismatic with Hunter-Schreger bands (HSB) and an outer zone of radial enamel. In the basilosaurid, the enamel is relatively thin and measures 150–180 μm, whereas in Llanocetus sp. it is considerably thicker, measuring 830–890 μm in the cusp area and 350–380 μm near the crown base. This is one of the thickest enamel layers among cetaceans, extinct and living. Structures resembling enamel tufts and lamellae were observed in both fossils at the enamel-dentine junction (EDJ) and extending along the thickness of the enamel layer, respectively. The presence of HSB and biomechanical reinforcing structures such as tufts and lamellae suggests prominent occlusal loads during feeding, consistent with raptorial feeding habits. Despite the simplification or absence of teeth in modern cetaceans, their ancestors had complex posterior teeth typical of most mammals, with a moderately thick enamel layer with prominent HSB.
      PubDate: 2019-01-17
       
  • Morphology and Evolution of the Xenarthra: an Introduction
    • PubDate: 2018-12-01
       
  • Epaxial Musculature in Armadillos, Sloths, and Opossums: Functional
           Significance and Implications for the Evolution of Back Muscles in the
           Xenarthra
    • Abstract: Abstract To investigate the evolution of xenarthran epaxial muscles, fresh specimens of the North American Common long-nosed armadillo Dasypus novemcinctus and of a marsupial, the Virginia opossum Didelphis virginiana, were dissected. Data from one fixed specimen of a two-toed sloth Choloepus didactylus were also used for comparison, because it is a xenarthran exhibiting a highly derived locomotor mode. The opossum was used to represent a more generalized mammalian condition. Each of the three mammalian epaxial muscle groups, the iliocostalis, longissimus dorsi, and transversospinalis, was removed and its mass was determined. All data were corrected for body mass and length. Unpaired, one-tailed t-tests showed the average mass of the iliocostalis and transversospinalis of Dasypus to be significantly larger than the mass of the same muscles in Didelphis, whereas the average mass of the longissimus dorsi was not statistically different between the two species. In agreement with pronounced lateral bending and de-emphasized dorso-ventral flexion and extension, Choloepus also had a relatively large iliocostalis and small longissimus. Our limited data suggest that this condition was inherited from non-arboreal and probably digging early xenarthrans. We believe the relatively larger iliocostalis and transversospinalis muscles in Dasypus can be attributed to the need to provide vertical stabilization of the trunk and resist lateral reaction forces generated by digging. Thus, for Xenarthra it represents a synapomorphy linked to adaptations for fossoriality.
      PubDate: 2018-12-01
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 54.160.19.155
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-