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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Determinants of reproductive status and mate choice in captive colonies of the naked mole-rat, Heterocephalus glaber

Clarke, Frank Michael January 1999 (has links)
No description available.
2

The distribution and abundance of herpetofauna on a Quaternary aeolian dune deposit : Implications for strip mining

Maritz, Bryan 04 November 2008 (has links)
Exxaro KZN Sands is planning the development of a heavy minerals strip mine south of Mtunzini, KwaZulu-Natal, South Africa. The degree to which mining activities will affect local herpetofauna is poorly understood and baseline herpetofaunal diversity data are sparse. This study uses several methods to better understand the distribution and abundance of herpetofauna in the area. I reviewed the literature for the grid squares 2831DC and 2831 DD and surveyed for herpetofauna at the study site using several methods. I estimate that 41 amphibian and 51 reptile species occur in these grid squares. Of these species, 19 amphibian and 39 reptile species were confirmed for the study area. In all, 29 new unique, grid square records were collected. The paucity of ecological data for cryptic fauna such as herpetofauna is particularly evident for taxa that are difficult to sample. Because fossorial herpetofauna spend most of their time below the ground surface, their ecology and biology are poorly understood and warrant further investigation. I sampled fossorial herpetofauna using two excavation techniques. Sites were selected randomly from the study area which was expected to host high fossorial herpetofaunal diversity and abundance. A total of 218.6 m3 of soil from 311 m2 (approximately 360 metric tons) was excavated and screened for herpetofauna. Only seven specimens from three species were collected. All were within approximately 100 mm of the surface even though some samples removed soil 1 m below the surface. There was no detectable difference in fossorial herpetofaunal density (individuals.m-2) between methods or from areas under different land uses. Neither soil compaction nor land use nor soil texture predicted fossorial herpetofaunal density or abundance. The data suggest that fossorial herpetofauna occur at extremely low densities in the area. This finding has implications for population estimates and conservation measures for these species. In order to better understand the effects of land use on herpetofaunal diversity, I used sample-based rarefaction curves to compare the diversity of the herpetofaunal species assemblages occurring in each of the four main land uses on the study site. Forest areas hosted significantly higher diversity than grasslands and the two agricultural mono-cultures, Eucalyptus and sugarcane plantations. Additionally I demonstrated empirically that riparian woodlands host higher species richness and herpetofaunal abundance than non-riparian areas. Potential reasons for the apparently suppressed diversity of these areas include the use of pesticides and/or herbicides, harvesting regimes, and the reduction in habitat heterogeneity. The potential value of riparian woodlands as refugia and corridors that could facilitate recolonisation of revegetated areas post-mining is discussed. Negative influences of mining activities on local herpetofauna are of particular interest given the potential and verified presence of several threatened taxa in the area including Bitis gabonica, Python natalensis, Afrixalus spinifrons, Hemisus guttatus and Hyperolius pickersgilli. These, as well as the “conservation needy” species proposed in a specialist report on the impacts of the mine on local herpetofauna are discussed in the light of my fieldwork. Mitigatory measures are required to reduce the negative impacts likely to be experienced by certain threatened taxa. I discuss a proposal for the development of a wetland reserve targeting, among other amphibian species, H. pickersgilli.
3

Phylogenetic Biology of the Burrowing Snake Tribe Sonorini (Colubridae)

Holm, Peter January 2008 (has links)
The Sonorini is a diverse assemblage of cryptozoic to fossorial snakes. Molecular and morphological evidence is ambiguous as to whether the tribe is monophyletic or consists of two or more independent clades. Morphological analysis, using Coluber constrictor and Liochlorophis vernalis as outgroups, indicates that the genera Conopsis, Ficimia, Gyalopion, Pseudoficimia, Stenorrhina, and Sympholis form the sister group to Chilomeniscus, Chionactis, and Sonora. This clade, in turn, is sister to Scolecophis and Tantilla. The putative genera Geagras and Tantillita are nested within the Tantilla calamarina and T. taeniata species groups, respectively.Each of the three major clades contains one or more highly fossorial forms that appear to be independently derived. Morphometric and natural history data from museum specimens, field studies, and the literature indicate that taxa with highly fossorial morphologies specialize on buried prey. Sympholis is at least a part-time commensal of leaf-cutting ants that feeds on beetle grubs; Chilomeniscus is a soil burrower that feeds on burrowing roaches and vermiform beetle larvae, whereas other members of the Ficimia and Sonora clades feed on various combinations of arachnids, orthopterans, and beetle grubs. Geagras redimitus, presumably a detritus burrower, feeds on vermiform beetle larvae, whereas Scolecophis and most Tantilla feed on centipedes. At least three other Tantilla species, including T. gracilis, T. relicta, and T. vermiformis, show parallel trends towards miniaturization, fossorial morphology, and diet of insect larvae.
4

Ecological impacts of Highveld gerbils (Tatera Brantsii) on a rehabilitated ash disposal site / Nevil Ian Wright

Wright, Nevil Ian January 2006 (has links)
Tatera brantsii was numerically dominant in the small mammal community on the plateaux of the rehabilitated ash disposal sites of ESKOM's Hendrina Power Station in 1998 and 1999 (Vermaak 2000). The species seemed well adapted to exploit this environment and, through biopedturbation, had altered the topsoil structure and chemistry. The consequences of this and other activities also affected the rehabilitated plant community of the PFA-dam habitat. Burrowing appeared limited to just under the topsoil layer, and seemed more extensive than burrows of this species in natural ecosystems. The burrow system architecture was mapped and quantified, and localised increases in nitrates, phosphorous and organic carbon in immediately associated substrate were noted. However, this substrate enrichment was transient, and disappeared following the abandonment, and subsequent collapse of burrow systems, when gerbil colonies migrated away from the area. The mixing of soil horizons also resulted in a more homogeneous substrate, which was more friable, and thus drier. The high pH and salinity of the topsoil layer in areas undisturbed by gerbil burrowing, and concentrations of particular elements associated with either the topsoil covering or the ash, were reduced as a consequence of substrate mixing in disturbed areas. Gerbil impacts on the substrate of this habitat seemed to promote pedogenesis, eliminating the sharp distinction between the topsoil covering and the ash below, but the re-exposed ash of the burrow mounds would become subject to erosion, and reduce the effectiveness of the rehabilitation effort. Gerbil activities increased the number of plant species, especially ruderal forbs, comprising the plant community of the PFA-dam habitat, but plant community diversity was not significantly increased. However, numerical dominance by few tussock grass species was diminished , possibly reflecting burial under mounds of excavated substrate. The biomass and cover of some grass species were reduced in areas of gerbil impacts, and plant lifecycles appeared to be completed sooner in areas affected by gerbil activities. These effects may be as a result of the drier substrate produced following the collapse of the extensive network of abandoned burrows. The succession of this plant community towards an underutilised grassland state, the expected outcome of the rehabilitation effort, was minimally affected by gerbil activities. The effects of T.brantsii activities in this PFA-dam habitat were not as distinct as the effects noted by other authors studying fossorial rodent impacts in less disturbed habitats. This could be because further disturbances in this habitat would merely add to the currently disturbed state, whereas disturbance in more natural habitats, would show more of a change from the initial state. / Thesis (M.Sc. (Zoology))--North-West University, Potchefstroom Campus, 2007.
5

Ecological impacts of Highveld gerbils (Tatera Brantsii) on a rehabilitated ash disposal site / Nevil Ian Wright

Wright, Nevil Ian January 2006 (has links)
Tatera brantsii was numerically dominant in the small mammal community on the plateaux of the rehabilitated ash disposal sites of ESKOM's Hendrina Power Station in 1998 and 1999 (Vermaak 2000). The species seemed well adapted to exploit this environment and, through biopedturbation, had altered the topsoil structure and chemistry. The consequences of this and other activities also affected the rehabilitated plant community of the PFA-dam habitat. Burrowing appeared limited to just under the topsoil layer, and seemed more extensive than burrows of this species in natural ecosystems. The burrow system architecture was mapped and quantified, and localised increases in nitrates, phosphorous and organic carbon in immediately associated substrate were noted. However, this substrate enrichment was transient, and disappeared following the abandonment, and subsequent collapse of burrow systems, when gerbil colonies migrated away from the area. The mixing of soil horizons also resulted in a more homogeneous substrate, which was more friable, and thus drier. The high pH and salinity of the topsoil layer in areas undisturbed by gerbil burrowing, and concentrations of particular elements associated with either the topsoil covering or the ash, were reduced as a consequence of substrate mixing in disturbed areas. Gerbil impacts on the substrate of this habitat seemed to promote pedogenesis, eliminating the sharp distinction between the topsoil covering and the ash below, but the re-exposed ash of the burrow mounds would become subject to erosion, and reduce the effectiveness of the rehabilitation effort. Gerbil activities increased the number of plant species, especially ruderal forbs, comprising the plant community of the PFA-dam habitat, but plant community diversity was not significantly increased. However, numerical dominance by few tussock grass species was diminished , possibly reflecting burial under mounds of excavated substrate. The biomass and cover of some grass species were reduced in areas of gerbil impacts, and plant lifecycles appeared to be completed sooner in areas affected by gerbil activities. These effects may be as a result of the drier substrate produced following the collapse of the extensive network of abandoned burrows. The succession of this plant community towards an underutilised grassland state, the expected outcome of the rehabilitation effort, was minimally affected by gerbil activities. The effects of T.brantsii activities in this PFA-dam habitat were not as distinct as the effects noted by other authors studying fossorial rodent impacts in less disturbed habitats. This could be because further disturbances in this habitat would merely add to the currently disturbed state, whereas disturbance in more natural habitats, would show more of a change from the initial state. / Thesis (M.Sc. (Zoology))--North-West University, Potchefstroom Campus, 2007.
6

Experimental Translocation of the Florida Sand Skink (<em>Plestiodon</em> [=<em>Neoseps</em>] <em>reynoldsi</em>): Success of a Restricted Species Across Diverse Microhabitats

Osman, Nicholas Paul 18 June 2010 (has links)
The fossorial Florida Sand Skink (Plestiodon [=Neoseps] reynoldsi) inhabits a restricted range of scrub and sandhill fragments on the ridges of central Florida. The high rate of urban and agricultural development in this area necessitates conservation strategies other than land acquisition and management because of the limited remaining Florida Sand Skink habitat available. This study tests the viability of translocation as a conservation strategy for this species and assesses which features of a recipient site contribute to the successful establishment of a population. In 2007, 300 individuals were collected and moved from an intact scrub habitat, individually marked, and moved to a nearby reclaimed site with no existing Florida Sand Skink population. Fifteen 20 m² enclosures were constructed at the recipient site, and 20 skinks were randomly assigned to each. These enclosures were divided among five treatments, which were represented the range of habitat types at the donor site and differed in the presence or absence of a shade-providing object and coarse woody debris. Translocated skinks were monitored for two years to measure survival and reproduction. While survival and reproduction were apparent in all treatments, survival was significantly greater in enclosures with no shade-providing object and low soil moisture, and reproduction was most evident in enclosures with less light intensity and soil compaction. Common measurement of environmental variables at the donor and recipient sites showed that all of the recipient site enclosures differed from the donor site in the amount of vegetative cover but contained the structural heterogeneity that is associated with Florida Sand Skink presence in the wild. This study indicates that translocation is a practical conservation strategy for this species, and my results can be used to inform protocol for future Florida Sand Skink translocation efforts.
7

Neuroecologia na ordem Rodentia: aspectos da cognição espacial em ratos-de-espinho e a evolução da encefalização / Spatial cognition and its relation with fossoriality in three species of spiny-rats (echimyidae: rodentia): evolutionary implications

Freitas, Jorge Nei Silva de 14 October 2013 (has links)
As diferentes demandas ecológicas impostas pela vida epígea e hipógea podem favorecer a melhoria das funções cognitivas espaciais. Comparamos a aprendizagem e a memória espacial, em labirinto complexo do Trinomys iheringi denigratus (terrestre de Mata Atlântica), T.yonenagae (semi-fossorial das Dunas na Caatinga) e Clyomys bishopi (fossorial do Cerrado). O aprendizado e memória espacial foram avaliados 10 T.i.denigratus (250±34g), 18 T.yonenagae (125±7,8g) e seis Clyomys bishopi (338±34g), a partir do: tempo até a saída do labirinto (TFL) e o número de erros cometidos (NER), em indivíduos colocados em labirinto de seis caminhos cegos e uma saída (0,20x1,10x1,50m), durante cinco testes consecutivos (30min) por dia, durante três dias consecutivos (fase de aprendizagem). Os ratos foram novamente testados em única sessão realizada após 48, 120 e 504h (fase de memória). O desempenho foi testado ao longo dos testes utilizando uma ANOVA um-fator (p<0,05). As taxas de aprendizagem (TA) do TFL das duas espécies foram mensuradas a partir do b da equação da curva de aprendizagem, e comparadas usando-se ANOVA um-fator (p<0,05). As variáveis do último teste de cada dia com os do primeiro teste do dia seguinte foram usadas como indicativas de memória-de-médio-prazo (MMP) e comparadas por espécie (teste T, dados-pareados, p<0,05). As taxas de retenção da aprendizagem (TR) com relação aos intervalos dos testes de memória, foram usadas como índice de memória-de-longo-prazo (MLP) e foram comparadas pela ANOVA um-fator (p<0,05). As espécies não apresentaram diferença significativa entre si mas não entre os testes tanto para TFL (F=0,85; p = 0,705; F=8,86; P < 0,000) quanto para NER (F=0,56; p=0,979; F = 3,65; p = 0,000). A TA foi marginalmente significativa (F = 2,784; p = 0,077) entre as espécies, sendo que T. yonenagae e C. bishopi não apresentaram diferença entre eles e ambos diferiram do T. i. denigratus. Com relação à memória-de-médio-prazo, T. Yonenagae e T. i. denigratus apresentaram diferença significativa para TFL entre os testes 10-11 (t = -3,406; p = 0,003) (t=- 2,300; p=0,050), mas não entre os testes 5-6 (t=-0,779; p=0,447) (t = -1,061; p=0,320). Já o C.bishopi sofreu redução entre os testes 5-6 e os testes 10-11, mas sem diferença significativa. Para a variável NER, não foi detectada diferença significativa, tanto para T. yonenagae (entre os 5 testes 5 e 6: t = 314,000, P = 0,558; testes 10 e 11: t=325,000, P=0,812) quanto para T.i.denigratus (entre os testes 5-6, t=0,590, P=0,562; testes 10-11: t=-1,855 P=0,080), por outro lado, C. bishopi apresentou a tendência de redução dos valores de NER entre os testes 5-6 (t = 0,442; p = 0,676) e 10-11 (t = 3,558; p = 0,016) sendo esta significativa. Quanto à MLP, dentre cada espécie não houve diferença significativa. Assim o semi-fossorial T.yonenagae e o fossorial C.bishopi se destacam quanto a aprendizagem do que a terrestre T.idenigratus, entretanto apenas C.bishopi é mais eficiente com relação a memoria-de-médio-prazo. Caso o efeito da filogenia seja controlada, sugere-se que o hábito fossorial seja componente do regime seletivo para evolução da cognição espacial / The different ecological contests imposed by epigeal and hypogeal lifestyles can facilitate the improvement of cognition spatial. We compared the spatial learning and memory in complex maze of Trinomys iheringi denigratus (terrestrial Atlantic rainforest), T.yonenagae (semifossorial Dunes of Caatinga) and Clyomys bishopi (fossorial of Cerrado). The spatial learning and memory were assessed 10 T.i.denigratus (250 ± 34g), 18 T.yonenagae (125 ± 7.8 g) and six Clyomys bishopi (338 ± 34g), from: time to exit the maze (TFL) and the number of errors (NER) in individuals placed on the complex maze of paths six blind and an outlet (0,20 x1, 10x1, 50m) for five consecutive tests (30min) per day for three consecutive days (learning phase) . The rats were tested in one session held after 48, 120 and 504Hours (memory phase). The performance was analyzed over the tests using a one-way ANOVA (p <0.05). Learning rates (TA) of the TFL of both species were measured from the b of the equation of the learning curve, and compared using one-way ANOVA (p <.05). The variables for each of the last test day with the first test the following day were used as indicators of memory to medium-term (MMP) and compared by species (t-test, paired-data, p <0.05) . Retention rates of learning (TR) with respect to the intervals of memory tests, were used as an index of memory-to-long-term (MLP) and were compared by one-way ANOVA (p <0.05). The species did not differ significantly from each other but not between tests for both TFL (F = 0.85, p = 0.705 F = 8.86, P <0.000) and for NER (F = 0.56, p = 0.979 , F = 3.65, p = 0.000). The TA was marginally significant (F = 2.784, p = 0.077) between species, and T. yonenagae and C. bishopi showed no difference between them and both were different from T. i. denigratus. With respect to memory-to-medium term, T. yonenagae and T. i. denigratus showed significant difference between the tests 11 and 10 for TFL (t = -3.406, p = 0.003) (t = -2.300, p = 0.050), but not between tests 5 and 6 (t = -0.779, p = 0.447 ) (t = -1.061, p = 0.320). Already C.bishopi showed decreased between tests 5-6 and tests 10-11, but without significant difference. For variable NER, no significant differences were detected for both T. yonenagae (between tests 5 and 6: t = 314.000, P = 0.558, Tests 10 and 11: t = 325,000 P = 0.812) and for T.i.denigratus (between tests 5.6, t = 0.590, P = 0.562; Tests 10-11: 7 t = -1.855 p = 0.080), on the other hand C. bishopi showed a trend to decreased NER between tests 5-6 (t = 0.442, p = 0.676) and 10-11 (t = 3.558, p = 0.016) which is significant. As for MLP, among each species there was no significant difference. Thus the semi-fossorial T.yonenagae and fossorial C.bishopi stand out as the learning of the terrestrial T.i.denigratus, however only C.bishopi is more efficient with respect to memory-to-medium term, if the effect of phylogeny is controlled, we suggested that the fossoriality could comprising the part of selective regime for evolution of the spatial cognition
8

Neuroecologia na ordem Rodentia: aspectos da cognição espacial em ratos-de-espinho e a evolução da encefalização / Spatial cognition and its relation with fossoriality in three species of spiny-rats (echimyidae: rodentia): evolutionary implications

Jorge Nei Silva de Freitas 14 October 2013 (has links)
As diferentes demandas ecológicas impostas pela vida epígea e hipógea podem favorecer a melhoria das funções cognitivas espaciais. Comparamos a aprendizagem e a memória espacial, em labirinto complexo do Trinomys iheringi denigratus (terrestre de Mata Atlântica), T.yonenagae (semi-fossorial das Dunas na Caatinga) e Clyomys bishopi (fossorial do Cerrado). O aprendizado e memória espacial foram avaliados 10 T.i.denigratus (250±34g), 18 T.yonenagae (125±7,8g) e seis Clyomys bishopi (338±34g), a partir do: tempo até a saída do labirinto (TFL) e o número de erros cometidos (NER), em indivíduos colocados em labirinto de seis caminhos cegos e uma saída (0,20x1,10x1,50m), durante cinco testes consecutivos (30min) por dia, durante três dias consecutivos (fase de aprendizagem). Os ratos foram novamente testados em única sessão realizada após 48, 120 e 504h (fase de memória). O desempenho foi testado ao longo dos testes utilizando uma ANOVA um-fator (p<0,05). As taxas de aprendizagem (TA) do TFL das duas espécies foram mensuradas a partir do b da equação da curva de aprendizagem, e comparadas usando-se ANOVA um-fator (p<0,05). As variáveis do último teste de cada dia com os do primeiro teste do dia seguinte foram usadas como indicativas de memória-de-médio-prazo (MMP) e comparadas por espécie (teste T, dados-pareados, p<0,05). As taxas de retenção da aprendizagem (TR) com relação aos intervalos dos testes de memória, foram usadas como índice de memória-de-longo-prazo (MLP) e foram comparadas pela ANOVA um-fator (p<0,05). As espécies não apresentaram diferença significativa entre si mas não entre os testes tanto para TFL (F=0,85; p = 0,705; F=8,86; P < 0,000) quanto para NER (F=0,56; p=0,979; F = 3,65; p = 0,000). A TA foi marginalmente significativa (F = 2,784; p = 0,077) entre as espécies, sendo que T. yonenagae e C. bishopi não apresentaram diferença entre eles e ambos diferiram do T. i. denigratus. Com relação à memória-de-médio-prazo, T. Yonenagae e T. i. denigratus apresentaram diferença significativa para TFL entre os testes 10-11 (t = -3,406; p = 0,003) (t=- 2,300; p=0,050), mas não entre os testes 5-6 (t=-0,779; p=0,447) (t = -1,061; p=0,320). Já o C.bishopi sofreu redução entre os testes 5-6 e os testes 10-11, mas sem diferença significativa. Para a variável NER, não foi detectada diferença significativa, tanto para T. yonenagae (entre os 5 testes 5 e 6: t = 314,000, P = 0,558; testes 10 e 11: t=325,000, P=0,812) quanto para T.i.denigratus (entre os testes 5-6, t=0,590, P=0,562; testes 10-11: t=-1,855 P=0,080), por outro lado, C. bishopi apresentou a tendência de redução dos valores de NER entre os testes 5-6 (t = 0,442; p = 0,676) e 10-11 (t = 3,558; p = 0,016) sendo esta significativa. Quanto à MLP, dentre cada espécie não houve diferença significativa. Assim o semi-fossorial T.yonenagae e o fossorial C.bishopi se destacam quanto a aprendizagem do que a terrestre T.idenigratus, entretanto apenas C.bishopi é mais eficiente com relação a memoria-de-médio-prazo. Caso o efeito da filogenia seja controlada, sugere-se que o hábito fossorial seja componente do regime seletivo para evolução da cognição espacial / The different ecological contests imposed by epigeal and hypogeal lifestyles can facilitate the improvement of cognition spatial. We compared the spatial learning and memory in complex maze of Trinomys iheringi denigratus (terrestrial Atlantic rainforest), T.yonenagae (semifossorial Dunes of Caatinga) and Clyomys bishopi (fossorial of Cerrado). The spatial learning and memory were assessed 10 T.i.denigratus (250 ± 34g), 18 T.yonenagae (125 ± 7.8 g) and six Clyomys bishopi (338 ± 34g), from: time to exit the maze (TFL) and the number of errors (NER) in individuals placed on the complex maze of paths six blind and an outlet (0,20 x1, 10x1, 50m) for five consecutive tests (30min) per day for three consecutive days (learning phase) . The rats were tested in one session held after 48, 120 and 504Hours (memory phase). The performance was analyzed over the tests using a one-way ANOVA (p <0.05). Learning rates (TA) of the TFL of both species were measured from the b of the equation of the learning curve, and compared using one-way ANOVA (p <.05). The variables for each of the last test day with the first test the following day were used as indicators of memory to medium-term (MMP) and compared by species (t-test, paired-data, p <0.05) . Retention rates of learning (TR) with respect to the intervals of memory tests, were used as an index of memory-to-long-term (MLP) and were compared by one-way ANOVA (p <0.05). The species did not differ significantly from each other but not between tests for both TFL (F = 0.85, p = 0.705 F = 8.86, P <0.000) and for NER (F = 0.56, p = 0.979 , F = 3.65, p = 0.000). The TA was marginally significant (F = 2.784, p = 0.077) between species, and T. yonenagae and C. bishopi showed no difference between them and both were different from T. i. denigratus. With respect to memory-to-medium term, T. yonenagae and T. i. denigratus showed significant difference between the tests 11 and 10 for TFL (t = -3.406, p = 0.003) (t = -2.300, p = 0.050), but not between tests 5 and 6 (t = -0.779, p = 0.447 ) (t = -1.061, p = 0.320). Already C.bishopi showed decreased between tests 5-6 and tests 10-11, but without significant difference. For variable NER, no significant differences were detected for both T. yonenagae (between tests 5 and 6: t = 314.000, P = 0.558, Tests 10 and 11: t = 325,000 P = 0.812) and for T.i.denigratus (between tests 5.6, t = 0.590, P = 0.562; Tests 10-11: 7 t = -1.855 p = 0.080), on the other hand C. bishopi showed a trend to decreased NER between tests 5-6 (t = 0.442, p = 0.676) and 10-11 (t = 3.558, p = 0.016) which is significant. As for MLP, among each species there was no significant difference. Thus the semi-fossorial T.yonenagae and fossorial C.bishopi stand out as the learning of the terrestrial T.i.denigratus, however only C.bishopi is more efficient with respect to memory-to-medium term, if the effect of phylogeny is controlled, we suggested that the fossoriality could comprising the part of selective regime for evolution of the spatial cognition
9

Revisão taxonômica do gênero Apostolepis Cope, 1862 (Serpentes, Dipsadidae, Xenodontinae, Elapomorphini) /

França, Daniella Pereira Fagundes de January 2018 (has links)
Orientador: Hussam El Dine Zaher / Resumo: Apostolepis Apostolepis é o gênero mais diversificado da Tribo Elapomorphini, composto por 40 espécies válidas, sendo 36 brasileiras e quatro que distribuem-se nas Guianas, Colômbia, Peru, Bolívia, Paraguai e Argentina. Apostolepis é reconhecido como um dos grupos taxonomicamente mais problemáticos de Dipsadidae, principalmente por causa de descrições de espécies com informações insuficientes, por vezes baseadas em variações intraespecíficas e em indivíduos anômalos. Mais de 50 táxons nominais são relacionados a Apostolepis, dos quais 21 foram descritos nos últimos 30 anos e 35 baseados apenas no holótipo; vários já sinonimizados a espécies descritas anteriormente. Por causa dos hábitos de vida as espécies do gênero não são abundantemente encontradas, fazendo com que muitas espécies ainda sejam minimamente conhecidas e outras conhecidas apenas pelo holótipo. Combinando todos esses fatores, foram gerados muitos equívocos na identificação das espécies, contribuindo para uma sucessão massiva de controvérsias taxonômicas e resultando no insatisfatório entendimento da evolução, ecologia e história natural das espécies do grupo. Por essas razões este estudo objetivou revisar a taxonomia das espécies atualmente alocadas no gênero, examinando séries de museus nacionais e internacionais, através de visitas, empréstimos e dados enviados pelas instituições. Analisei caracteres merísticos de 1803 espécimes provenientes de 32 coleções científicas na América do Sul, Estados Unidos e Europa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Apostolepis is the most diverse genus of the Tribe Elapomorphini. It is composed of 40 valid species, being 36 from Brazil and others distributed in the Guianas, Colombia, Peru, Bolivia, Paraguay and Argentina. The genus Apostolepis is recognized as one of the most problematically taxonomic groups of Dipsadidae because original species descriptions with insufficient information, sometimes based on intraspecific variations and anomalous specimens. More than 50 nominal taxa are related to Apostolepis, of which 21 were described in the last 30 years and 35 based only on the holotype; several taxa already synonimized to species described above. Because of life habits of species are not abundantly found, causing that many species are still minimally known and others known only by the holotype. Combining all these factors, many misunderstandings were generated in the identification of the species, contributing to a massive succession of taxonomic controversies and resulting in an unsatisfactory understanding of the evolution, ecology and natural history of the species. For these reasons, this study aimed to review the taxonomy of species currently allocated to the genus, examining series of European, South and North American museums through visits, loans and data sent by institutions. Of 1803 specimens from 32 scientific collections, referring to 50 nominal taxa I analyzed meristic characters, of small part I observed the hemipenian and cranial morphology, of about 817 specimens ob... (Complete abstract click electronic access below) / Doutor
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Palaeontology of primitive wombats

Brewer, Philippa, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Wombats (Vombatidae, Marsupialia) are fossorial marsupials that are most closely related to koalas amongst living marsupials. The cheek teeth of wombats are unique amongst Australian marsupials in being hypselodont (the condition where the teeth continue to grow throughout life and the formation of roots is suppressed). Hypselodonty is an adaptation to high degrees of tooth wear. The fossil record of vombatids is largely restricted to Pliocene to recent deposits and is largely represented by isolated teeth. Six genera are currently recognised from these deposits, all of which have hypselodont teeth. To date, a single isolated vombatid tooth has been described from pre-Pliocene deposits of South Australia and is the only example of a vombatid cheek tooth that possesses roots. Seventy specimens, representing five species of vombatid, have been recovered from Oligo-Miocene deposits in the Riversleigh World Heritage Site in northwestern Queensland and are described here. Among these are four new species and one new genus. A new species of Warendja from Riversleigh is described. It represents the oldest known hypselodont vombatid. This species is compared with additional specimens of the Pleistocene species of Warendja (W wakefieldi). Three species of Rhizophascolonus and a new monotypic genus are also described. Phylogenetic analysis of these taxa indicates that Rhizophascolonus may represent a sister taxon to the other vombatids. These specimens comprise almost all known examples of Oligo-Miocene vombatids. Most of the specimens are isolated teeth and are highly variable in size and morphology. Cusp detail is clearly preserved on many, allowing for omparison with the cusp morphology on juvenile cheek teeth of the common wombat (Vombatus ursinus). All of the taxa found in the deposits at Riversleigh share a number of characters such as marked differences in enamel thickness and height around the cheek teeth. It is argued here that these shared characters are indicative of high amounts of tooth wear and/or occlusal stresses acting on the trailing edge enamel. Combined with evidence of scratch-digging adaptations of the forelimbs it is suggestive of a rhizophagous niche for at least some of these early vombatids.

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