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At least 253 records · Page 14Linked to original sources

PubMed2001

Do big-brained animals play more? Comparative analyses of play and relative brain size in mammals.

It has been hypothesized that play is more likely to be present in larger brained species. We tested this hypothesis in mammals using independent contrasts, a method that controls for phylogenetic relatedness. Comparisons across 15 orders revealed that the prevalence and complexity of play was significantly correlated with brain size, with larger brained orders having more playful species. Three orders, Rodentia, Marsupialia, and Primates, were used for within-order comparisons among species and, where possible, among families. The comparisons were not significant for rodents or primates, and those for marsupials yielded inconsistent results. Therefore, although a strong relationship is present at the highest taxonomic level of comparison, it diminishes or evaporates at lower level comparisons.

Animals↗

PubMedDate not supplied

Novel sex differences in linkage values and meiotic chromosome behaviour in a marsupial.

There have been few reported family studies of gene segregation in marsupials and no report on genetic linkage in a marsupial species. The paucity of such genetic data probably stems from the lack of marsupial species sufficiently well adapted to a laboratory environment to give the abundant progeny from controlled crosses which are required in such work. A colony of the fat-tailed insectivore Sminthopsis crassicaudata (Marsupialia: Dasyuridae), which was established in the R. A. Fisher Laboratories, University of Adelaide, more than 20 years ago, has now provided unusual linkage data. These data indicate that the linkage situation in this marsupial species differs markedly from that in eutherian mammals. Extremely large differences exist between the sexes in the values of the recombination frequencies, with much closer linkage occurring in females. Cytological examination of meiosis in males and females has revealed a major difference between the sexes in chromosome behaviour.

Animals↗

PubMed1978

The use of marsupial x eutherian somatic cell hybrids to study marsupial cell surface antigens.

Buck and Bodmer (1976) have developed a technique for identifying an antigen on the surface of human x mouse somatic cell hybrids, specified by a gene on a particular human chromosome. We have successfully adapted this technique to a study of marsupial cell surface antigens. Somatic cell hybrids between Macropus rufus (Marsupialia) lymphocytes and the mouse cell lines PG19 and 1R were injected intraperitoneally into mice of the same inbred strain from which the above cell lines were derived (C57B16J and C3H, respectively). The only identified M. rufus chromosome present in the hybrid cells was the X chromosome. The antisera, after adsorption with PG19 or 1R, were tested using indirect immunofluorescence, against the hybrid cells, and also against sub-clones (derived from hybrids) which had apparently lost the M. rufus X chromosome, or at least its long arm. The results of these tests showed that the absorbed antisera contained reactivity against an M. rufus cell surface antigen (or antigens). The reactions of one of the antisera were most simply interpreted by supposing that it was detecting an M. rufus X-lined antigen(s).

Animals↗

PubMed1982

Anatrichosoma haycocki sp. n. (Nematoda: Trichuridae) from the paracloacal glands of Antechinus spp. With notes on Skrjabinocapillaria skarbilovitsch.

Anatrichosoma haycocki sp. n. (Nematoda: Trichuridae) is described from the paracloacal glands of Antechinus swainsonii (Waterhouse, 1840) and A. stuartii Macleay, 1841 (Marsupialia: Dasyuridae) from Nadgee State Forest, New South Wales, Australia. Immature male and female worms occur free in the intestine. A. haycocki is distinguished from other species of Anatrichosoma by the following suite of morphological characters: small size, absence of longitudinal cuticular striations in both sexes, subterminal constriction of male tail bearing 14 minute papillae and inflation of posterior portion of mature female giving Trichuris-like appearance. It is also characterised by its occurrence in paracloacal glands in a genus of small carnivorous dasyurid marsupial restricted to Australia and New Guinea. Skrjabinocapillaria rodentium Wertheim and Chabaud, 1979 is recognised as a synonym of Anatrichosoma gerbillis (Bernard, 1964). The genus Skrjabinocapillaria Skarbilovitsch, 1946 is placed as a synonym of Capillaria Zeder, 1800, resulting in the new combination for the type species: C. eubarsata (Skarbilovitsch, 1946) comb. nov. It is suggested that deep penetration of the female uterus by the male at insemination is a behavioural feature common to members of the Trichinelloidea and that the morphology of the male reproductive tract reflects the mechanisms of penetration employed by members of each genus.

Animals↗

PubMed1997

High-precision 40Ar/39Ar geochronology and the advent of North America's Late Cretaceous terrestrial fauna.

A densely sampled, diverse new fauna from the uppermost Cedar Mountain Formation, Utah, indicates that the basic pattern of faunal composition for the Late Cretaceous of North America was already established by the Albian-Cenomanian boundary. Multiple, concordant 40Ar/39Ar determinations from a volcanic ash associated with the fauna have an average age of 98.39 +/- 0.07 million years. The fauna of the Cedar Mountain Formation records the first global appearance of hadrosaurid dinosaurs, advanced lizard (e.g., Helodermatidae), and mammal (e.g., Marsupialia) groups, and the first North American appearance of other taxa such as tyrannosaurids, pachycephalosaurs, and snakes. Although the origin of many groups is unclear, combined biostratigraphic and phylogenetic evidence suggests an Old World, specifically Asian, origin for some of the taxa, an hypothesis that is consistent with existing evidence from tectonics and marine invertebrates. Large-bodied herbivores are mainly represented by low-level browsers, ornithopod dinosaurs, whose radiations have been hypothesized to be related to the initial diversification of angiosperm plants. Diversity at the largest body sizes (>10(6) g) is low, in contrast to both preceding and succeeding faunas; sauropods, which underwent demise in the Northern hemisphere coincident with the radiation of angiosperms, apparently went temporarily unreplaced by other megaherbivores. Morphologic and taxonomic diversity among small, omnivorous mammals, multituberculates, is also low. A later apparent increase in diversity occurred during the Campanian, coincident with the appearance of major fruit types among angiosperms, suggesting the possibility of adaptive response to new resources.

Animals↗

PubMedDate not supplied

Molecular identification of uncoupling proteins 2 and 3 in a carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii).

This study investigated the expression of uncoupling proteins 2 and 3 (UCP2 and UCP3) in the carnivorous marsupial Sarcophilus harrisii. The current study used molecular techniques to ascertain whether this species expresses UCP2 and/or UCP3. This species increases nonshivering thermogenesis in response to cold exposure and norepinephrine, although our previous study was unable to demonstrate the presence of brown adipose tissue or uncoupling protein 1. Samples of skeletal muscle and white adipose tissues were taken from five S. harrisii pre- and post-cold acclimation (2 degrees -3 degrees C for 2 wk). The tissues were examined for UCP2 and UCP3 expression through Western blots and reverse transcriptase polymerase chain reaction, with subsequent sequencing to ensure identification of the desired gene. These data suggest that S. harrisii expresses UCP2 but not UCP3. The sequencing of the amplified S. harrisii UCP2 cDNA has revealed a 76% homology with human UCP2 cDNA and a 72% homology with rat UCP2 cDNA. The expression of UCP2 but not UCP3 suggests that UCP2 is conserved from a common ancestor to both the Marsupialia and the Eutheria taxa.

Acclimatization↗

PubMed2005

The platypus is in its place: nuclear genes and indels confirm the sister group relation of monotremes and Therians.

Morphological data supports monotremes as the sister group of Theria (extant marsupials + eutherians), but phylogenetic analyses of 12 mitochondrial protein-coding genes have strongly supported the grouping of monotremes with marsupials: the Marsupionta hypothesis. Various nuclear genes tend to support Theria, but a comprehensive study of long concatenated sequences and broad taxon sampling is lacking. We therefore determined sequences from six nuclear genes and obtained additional sequences from the databases to create two large and independent nuclear data sets. One (data set I) emphasized taxon sampling and comprised five genes, with a concatenated length of 2,793 bp, from 21 species (two monotremes, six marsupials, nine placentals, and four outgroups). The other (data set II) emphasized gene sampling and comprised eight genes and three proteins, with a concatenated length of 10,773 bp or 3,669 amino acids, from five taxa (a monotreme, a marsupial, a rodent, human, and chicken). Both data sets were analyzed by parsimony, minimum evolution, maximum likelihood, and Bayesian methods using various models and data partitions. Data set I gave bootstrap support values for Theria between 55% and 100%, while support for Marsupionta was at most 12.3%. Taking base compositional bias into account generally increased the support for Theria. Data set II exclusively supported Theria, with the highest possible values and significantly rejected Marsupionta. Independent phylogenetic evidence in support of Theria was obtained from two single amino acid deletions and one insertion, while no supporting insertions and deletions were found for Marsupionta. On the basis of our data sets, the time of divergence between Monotremata and Theria was estimated at 231-217 MYA and between Marsupialia and Eutheria at 193-186 MYA. The morphological evidence for a basal position of Monotremata, well separated from Theria, is thus fully supported by the available molecular data from nuclear genes.

Amino Acid Sequence↗

PubMed1982

The relative DNA contents of the eutherian and marsupial X chromosomes.

The relative DNA contents of individual chromosomes of Sminthopsis crassicaudata (Marsupialia) have been measured by DNA cytophotometry. Measurements of the relative nuclear DNA contents of man and Sminthopsis have been made and show that the DNA content of the marsupial X chromosome is substantially less than that of the X chromosome of man. The implications of this observation with respect to the argument of the conserved X chromosome in mammals are presented.

Animals↗

PubMed1996

Serological survey of small mammals in a vesicular stomatitis virus enzootic area.

Small mammals were captured in a Costa Rican dairy farm located in a vesicular stomatitis virus (VSV) enzootic focus, in order to determine which species were naturally infected by this virus. Monthly captures were performed from March 1989 to February 1990. Eighty-four individuals belonging to the orders Rodentia (n = 52), Insectivora (n = 31) and Marsupialia (n = 1) were captured. Only Sigmodon hispidus had neutralizing antibodies to VSV; among 21 animals, six had antibodies to Indiana, one to New Jersey, and two to both serotypes. In addition, groups of 40 sentinel mice (Mus musculus, strain C3H) were placed in cages distributed throughout the farm. Each group was exposed for 1 mo over a period of 1 yr. None of 312 sentinel mice developed antibodies against either VSV serotype. Based on these results, we believe that S. hispidus might be part of the natural cycle of VSV in this enzootic focus. Caged Mus musculus do not seem appropriate for monitoring VSV activity in this area.

Animals↗

PubMed2003

Provision of tricuspid valve leaflets by septal papillary muscles in the right ventricle of human and other mammal hearts.

Leaflets of the tricuspid valve are provided by tendinous cords extending from the papillary muscles. The situation is complicated with the septal muscles, which generally occur in two groups, one as constant musculus coni arteriosi and the second as other variable septal muscles. We tested whether there is a variability in the provision of the tricuspid valve in different taxonomical groups of mammals. The material examined consisted of 299 hearts of mammals (Primates, Ungulata, Carnivora, Lagomorpha, Rodentia, Marsupialia). The musculus coni arteriosi in the majority of mammals provided only the front leaflet, but among Ungulata and Rodentia it provided simultaneously the front and septal leaflet. The other septal muscles provided the front, septal and even back leaflets. The following regularity was observed: in the hearts of Primates provision of the front leaflet and the front part of the septal leaflet predominated, among Ungulata the muscles provided the middle part of the septal leaflet, but among the other mammals the rest of the septal muscles provided, significantly, the back part of the septal leaflet. Such a provision was characteristic for predators, hares, rodents and marsupials. These circumstances may allow the conclusion to be drawn that there is a taxonomical dependence in the provision of the tricuspid valve in the hearts of the mammals under examination.

Animals↗

PubMed1991

[Aponeurosis plantaris--phylogenetic development].

The plantar aponeurosis is differentiated in its most primitive form in Marsupialia, where it is formed by a single connective tissue strip, a continuation of the tendon of the m. plantaris. The tendon is usually not fixed to the calacaneal tuberosity. The lateral tract (fibular) of the plantar aponeurosis takes a distal course and forms processes for the first to fifth toe. (The number of inserting strips is different and variable in different species of marsupials). A separate medial (tibial) strip of the aponeurosis is lacking. 2. In Insectivora the plantar aponeurosis is differentiated similarly as in marsupials. Again the medial (tibial) strip of the aponeurosis is absent and the tendon of the m. plantaris is more firmly fixed to the calcaneus. Scandentia (Tupalia) have a two-layer aponeurosis. The fibular (lateral) layer is in continuation of the tendon of the m. plantaris, the medial (tibial) layer starts at the calcaneal tuberosity. The plantar aponeurosis of Tupalia does not yet form two separable tracts, however, the forming layers of the aponeurosis indicate the future separation of the uniform connective tissue plate. 3. In prosimians and simians a separate medial (tibial) tract develops which is independent on the tendon of the m. plantaris, and in anthropoids and humans gradually the planta predominates.

Animals↗

PubMed1989

Ultrastructural variation in enamel of Australian marsupials.

This paper initiates a survey of the enamel of fossil and extant Australian marsupials by scanning electron microscopy. Enamel was examined from 17 extant and 11 extinct marsupials. Assessment was made of prism packing pattern, prism course, tubule presence, tubule size and distribution. Values calculated were: prism diameter; prism axis ratio; cross-sectional prism area; cross-sectional ameloblast area; and numerical prism density. Three different prism packing arrangements were found for extant and fossil marsupials within the classical Pattern 2. The Pattern 1 arrangement found in three extant species was relatively unexpected given the general acceptance of Marsupialia as having Pattern 2 enamel. Attention is drawn to the variable loss of prism demarcation towards the outer enamel surface. The majority of both extant and fossil marsupials exhibited a simple radial prism course. Prism diameters were small ranging from 1.4 micron to 3.9 micron and prism densities were high, compared to those for human and multituberculate enamel. A significant inter-species variation was noted in the presence and size of enamel tubules. The absence of enamel tubules in the incisors of D. optatum, N. tedfordi and T. rostratus and the molar of W. wakefieldi was confirmed. Large bulbous spaces were found either along or at the termination of enamel tubules in some teeth of five fossil species: these spaces may represent the resting place of an ameloblast. We have found: a greater variation in prism packing patterns; a greater difference in characteristics studied between incisor and molar teeth; and a greater variety of tubule morphology than anticipated. There are signs that useful enamel ultrastructural characters are emerging to help ultimately with taxonomic investigations of Australian marsupials.

Animals↗

PubMed1986

[Upright posture of man and morphologic evolution of the musculi extensores digitorum pedis with reference to evolutionary myology. III].

The following anatomical objects were studied with regard to myology during evolution: M. extensor hallucis longus (MEHL), M. extensor digitorum longus (MEDL) with M. peroneus tertius (MP III), M. peroneus brevis (MPB) with M. peroneus digiti V (MPD V), M. extensor hallucis brevis (MEHB), M. extensor digitorum brevis (MEDB), and the Retinaculum musculorum extensorum imum (RMEI). The study was carried out by the preparation of 3 different groups of material. The 1st group consists of lower extremities of humans. The number of the extremities differs for the particular objects between 151 and 358 (see page 381). The 2nd group of material consists of 122 Membra pelvina from Marsupialia, Insectivora, and Primates. Table 1 shows as well the mammalian species as the number of the studied extremities. The extremities of the 1st and 2nd group were preserved in an manner suitable for a macroscopic preparation. The 3rd group of material consists of 71 lower extremities from embryos and fetus. The lower legs and feet were stained either according to the method described by Morel and Bassal with eosin added or according to Weigert. From this material, complete series of cross sections were prepared. Table 2 shows the age of the embryos (VCL [mm]) as well as the number of the studied extremities. It is important that up to the age of 46 mm VCL the difference in the age of the embryos usually amounts from 0.5 to 1.0 mm. This small difference in the age of the embryos and fetus allows a very good follow up of the changes in construction during the organogenesis. The comparison of the 3 different groups shows the following changes for the above mentioned muscles: The M. extensor hallucis longus (MEHL) is a muscle which is not split. The same result applies for its tendon which inserts at the distal phalanx of the hallux. This primitive form of the muscle amounts actually to 51.12% in human beings. In 48.88% of the cases, additional tendons and muscles are formed by the MEHL. Most of these supplements are positioned on the medial side of the main tendon, only a few lie to the lateral side. For the supplement tendons, the medial one as well as the lateral one occasionally possess a muscle belly. The muscle of the medial tendon is split off from the proximal margin of the MEHL. The muscle of the lateral tendon is split off from the distal margin of the MEHL.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1984

[Comparative anatomical studies of the vomeronasal complex and the rostral palate of various mammals. I].

The anatomy of the vomeronasal complex and, in connection with this, the structures of the rostral palate were studied in different species of mammals, namely members of the order Marsupialia, Scandentia, Insectivora, Primates, Rodentia, and Lagomorpha. The following results were obtained: The organs of Jacobson of all forms studied are well-developed. The organ of Jacobson is situated at the base of the nasal septum and opens rostrally, always closely connected to the nasopalatine duct. Even in rodents, lagomorphs and Solenodon, where the openings of the organs are positioned rostral to the ductus, both systems are nevertheless connected by means of special furrows. Accordingly the organs of Jacobson are functionally much more closely related to the oral cavity than to the nasal cavity, which they actually belong to. This can be emphasized by the peculiar structures of the rostral palate inclosing the papilla palatina and with it the oral openings of the nasopalatine ducts. In all species studied, the anterior part of the upper jaw presents a very interesting situation because the median furrow of the rhinarium communicates directly or indirectly with the sulcus papillae palatinae, thus forming a very distinct system of grooves which preserves a connection between the nasopalatine ducts and the preoral surroundings. In rodents, lagomorphs, and Solenodon, we find in this part of the palate a special situation because of their unusually arranged incisors, which are not separated by a diastema. However, also in these cases, there are distinct connecting passages between the papilla palatina and the extraoral surroundings. The conditions found in Ratufa bicolor and in early stages of the rat demonstrate that the extraordinary topography of the rostral palate in rodents is a secondary formation by means of ontogeny and phylogeny. Cebus apella, a platyrrhine simian, shows already a clear reduction of palatal structures compared to those found in prosimians. In Setifer setosus and Echinops telfairi, we find the papilla palatina and with it the oral openings of the nasopalatine ducts overgrown by a bipartite caudal branch of the rhinarium. The neonate Setifer allows us to reconstruct the mechanism of this overgrowing procedure. We find a similar situation in Erinaceus, where the papilla palatina remains uncovered, however. Because of contradictory bibliographical data, some elements of the vomeronasal complex in mammals needed to be carefully analysed in regard to structure and nomenclature: in many species the paraseptal cartilage bifurcates rostrally into a dorsal and a ventral branch.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗

PubMed1994

A new species of Oesophagostomoides (Nematoda: Cloacinidae) from the northern hairy-nosed wombat Lasiorhinus krefftii with a key to species of the genus.

Lasiorhinus krefftii, the northern hairy-nosed wombat, is a rare and endangered marsupial existing as a single population in the Epping Forest National Park, Queensland, Australia. Dissection of a juvenile wombat that had died from natural causes revealed the presence in the colon of a new species of Oesophagostomoides Schwartz, 1928, a genus found only in wombats (Vombatidae, Marsupialia). Oesophagostomoides eppingensis n. sp. differs from the other species in the genus in the length of spicule, form of the dorsal ray, length of the vagina, and proportions of the female's posterior end. Morphological similarities between species suggest that there may have been switching of the species of Oesophagostomoides between L. krefftii and Vombatus ursinus (the common wombat). The potential contribution of colon parasites to the energy budget of wombats may be of importance when determining conservation management strategies for L. krefftii.

Animals↗

PubMedDate not supplied

[The systematic position of Hymenolepididae (Cestoda) from Australian marsupials].

A review of Hymenolepididae from Australian Marsupialia is given. These cestodes are transmitted out of the genus Hymenolepis, into which they were previously included. 3 species of them are transmitted to the genus Rodentolepis, and 7 species are arranged as a new genus Potorolepis. The diagnosis of Potorolepis and a list of species included are given. Possible phylogenetic relations of the genus Potorolepis with nearest groups of cestodes are discussed.

Animals↗

PubMed2005

Evolution of the vertebral formulae in mammals: a perspective on developmental constraints.

Developmental constraints refer to biases that limit phenotypic changes during evolution. To examine the contribution of developmental constraints in the evolution of vertebrate morphology, we analyzed the distribution pattern of mammalian vertebral formulae. Data on mammalian vertebral formulae were collected from the Descriptive Catalogue of the Osteological Series Contained in the Museum of the Royal College of Surgeons of England by Richard Owen (1853) and were plotted onto the most reliable mammalian phylogenetic tree based on recent molecular studies. In addition to the number of cervical vertebrae that is almost fixed to 7, we found that the number of thoracolumbar vertebrae tends to be 19 in many groups of mammals. Since fidelity of the number of thoracolumbar vertebrae was also completely maintained in Monotremata and Marsupialia, we presumed that thoracolumbar vertebral number as well as cervical vertebral number might have been fixed in the primitive mammalian lineage. On the basis of primitive vertebral formulae, we could clarify the polarity of evolution and identify several deviations from the primitive states during the mammalian evolution. The changes in the vertebral formulae in eutherian mammals seem to be lineage-specific, such that most species in Carnivora have 20 instead of 19 thoracolumbar vertebrae. Because such lineage-specific vertebral formulae contrast with the estimated distribution pattern on the assumption of evolution only through the selective pressure, we concluded that developmental constraints played an important role in the evolution of mammalian vertebral formulae.

Animals↗

PubMed1998

The function of vigilance in sympatric marsupial carnivores: the eastern quoll and the Tasmanian devil.

Sympatric marsupial carnivore (Marsupialia: Dasyuridae) species experience different levels of risk of predation and competition as a consequence of different body size and feeding adaptations. The small eastern quoll, Dasyurus viverrinus, is preyed upon by owls and is aggressively displaced from carcasses by its larger competitor and potential predator, the Tasmanian devil, Sarcophilus laniarius. Devils have no known predators but this specialized scavenger experiences intense intraspecific competition. I studied the vigilance behaviour of individuals of these species feeding on carcasses. (1) Eastern quolls were more vigilant in the presence than in the absence of devils, suggesting that their vigilance functions to detect predators/competitors. (2) Devils showed a decrease in vigilance with increasing body size and age, and a trend towards a decrease with increasing group size. These are the same patterns expected if vigilance was in response to predation risk, although devils have no predators. Vigilance behaviour did not change in the presence of eastern quolls, suggesting that vigilance is not directed towards interspecific competitors. (3) As expected from their greater risk of predation and injury from a larger competitor, eastern quolls appeared to invest more in vigilance than devils did: they used vigilance postures that gave better visibility but disrupted feeding more. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗