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La région de l’oreille osseuse chez les Proboscidea (Afrotheria, Mammalia) : anatomie, fonction, évolution / The ear region of the Proboscidea (Afrotheria, Mammalia) : anatomy, function, evolutionSchmitt, Arnaud 04 October 2016 (has links)
Les éléphants font partie des rares mammifères capables d’entendre les infrasons et leur comportement locomoteur est unique. Ces singularités correspondent à des spécialisations de leurs organes sensoriels contenus dans l’oreille interne : la cochlée (audition) et le système vestibulaire (locomotion). Alors que la diversité actuelle des proboscidiens est très faible (trois espèces), ce groupe a été bien plus diversifié pendant les 60 millions d’années qui composent son histoire. Cette thèse étudie pour la première fois de façon complète la morphologie et la fonction de la région de l’oreille (périotique, labyrinthes osseux et membraneux) d’éléphants actuels grâce aux techniques CT scan 3D. De plus, les périotiques de quatorze genres de proboscidiens fossiles sont décrits afin de documenter l’évolution de ce complexe anatomique au sein de cet ordre de mammifères. Les résultats montrent que certains caractères de l’oreille sont très variables au niveau spécifique. Notre analyse inclut les plus anciens proboscidiens connus et suggère que la morphologie de la région otique a évolué graduellement pendant la première moitié de l’histoire évolutive du groupe et que le morphotype moderne éléphantin est déjà acquis chez les Deinotheriidae et généralisé chez les éléphantimorphes. Les inférences sur la locomotion et l’audition des taxons fossiles confirment ces observations. Ce travail permet ainsi de lever le voile sur l’évolution d’une région anatomique majeure, jusque-là méconnue chez un groupe emblématique de mammifères. / Elephants are among the few mammals able to hear infra-sounds, and they display a unique locomotor behavior. It corresponds to specializations of their sensory organs contained in the inner ear: the cochlea (audition) and the vestibular system (spatial orientation). While only three species are living today, they were a much more diverse group found in five continents and with a 60 Ma-long history. We provide here the first comprehensive morphological and functional study of the ear region (petrosal, bony and membranous labyrinths) of extant elephants using 3D CT scan techniques. Additionally, we describe and compare the petrosals of fourteen extinct proboscidean genera in order to shed light on the evolution of this anatomical complex in the Proboscidea. The results show that some features of the petrosal and bony labyrinth of extant elephants - such as the number of turns of the cochlea – display a noticeable level of intra-specific variability. Our analysis includes the earliest-known proboscideans and suggests that the petrosal and bony labyrinth morphology evolved gradually during the first half of the proboscidean evolutionary history, but also that the modern morphotype exhibited in elephants was probably already acquired in deinotheriids and generalized in elephantimorphs. Functional inferences on the locomotor behavior and the audition of extinct proboscideans confirm these observations. This work hence provides new insights on the evolution of a major anatomical region hitherto poorly known in an emblematic group of mammals.
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Contribuição ao estudo dos Proboscidea (Mammalia, Gomphotheriidae) do quaternário do Estado do Rio Grande do Sul, BrasilMarcon, Gabrielli Teresa Gadens January 2007 (has links)
A revisão de espécimes já descritos e o estudo de novos espécimes permitiu identificar Stegomastodon waringi como o único proboscídeo registrado para os municípios de Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. Observou-se ainda um tamanho relativamente maior, e uma maior complexidade relativa no padrão de desgaste oclusal dos molares da espécie no Estado do Rio Grande do Sul, quando comparados com dentes homólogos dos demais estados do Brasil. / The revision of the already described and of new specimens allowed the identification Stegomastodon waringi as the only proboscidean found in the municipalities of Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. It was also observed that the molars are relatively larger, and that their occlusal wear pattern is relatively more complex in the molars of the species in the Rio Grande do Sul State when compared to those from the other Brazilian states.
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Contribuição ao estudo dos Proboscidea (Mammalia, Gomphotheriidae) do quaternário do Estado do Rio Grande do Sul, BrasilMarcon, Gabrielli Teresa Gadens January 2007 (has links)
A revisão de espécimes já descritos e o estudo de novos espécimes permitiu identificar Stegomastodon waringi como o único proboscídeo registrado para os municípios de Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. Observou-se ainda um tamanho relativamente maior, e uma maior complexidade relativa no padrão de desgaste oclusal dos molares da espécie no Estado do Rio Grande do Sul, quando comparados com dentes homólogos dos demais estados do Brasil. / The revision of the already described and of new specimens allowed the identification Stegomastodon waringi as the only proboscidean found in the municipalities of Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. It was also observed that the molars are relatively larger, and that their occlusal wear pattern is relatively more complex in the molars of the species in the Rio Grande do Sul State when compared to those from the other Brazilian states.
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Contribuição ao estudo dos Proboscidea (Mammalia, Gomphotheriidae) do quaternário do Estado do Rio Grande do Sul, BrasilMarcon, Gabrielli Teresa Gadens January 2007 (has links)
A revisão de espécimes já descritos e o estudo de novos espécimes permitiu identificar Stegomastodon waringi como o único proboscídeo registrado para os municípios de Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. Observou-se ainda um tamanho relativamente maior, e uma maior complexidade relativa no padrão de desgaste oclusal dos molares da espécie no Estado do Rio Grande do Sul, quando comparados com dentes homólogos dos demais estados do Brasil. / The revision of the already described and of new specimens allowed the identification Stegomastodon waringi as the only proboscidean found in the municipalities of Dom Pedrito, Iraí, Itaqui, Nova Palma, Osório, Pântano Grande, Quaraí, Rosário do Sul, Santa Vitória do Palmar e São Gabriel. It was also observed that the molars are relatively larger, and that their occlusal wear pattern is relatively more complex in the molars of the species in the Rio Grande do Sul State when compared to those from the other Brazilian states.
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A Paleontological Analysis of Late Pleistocene Proboscidea from Saltville, Virginia: Taphonomy, Systematic Paleontology, and PaleobiologySilverstein, Rachel 01 May 2017 (has links)
Saltville, Virginia (Smyth County and Washington County) has been known for its late Pleistocene megafauna since the 1700s. Based on reviews of past excavations and material in collections, the most prominent fossils found at Saltville are proboscideans. Teeth of Mammuthus (mammoth) and Mammut (mastodon) from East Tennessee State University Museum of Natural History, Virginia Museum of Natural History, and Smithsonian were the focus of this research. Evidence of sedimentary abrasion and degree of concretion development was used to address the taphonomic history of the assemblage. Evidence of root resorption, tooth expectoration, and eruption and wear of proboscidean molars was used to understand age-related patterns in the proboscidean assemblage. The Saltville proboscidean assemblage contains a disproportionate amount of juvenile mammoth and mastodon teeth, some of which were lost in life. This assemblage has also been modified extensively by sedimentary abrasion.
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A Phylogenetic Study of the Plant Family Martyniaceae (Order Lamiales)January 2011 (has links)
abstract: Acceptance of the plant group Martyniaceae as a distinct family has long been questioned. Previously placed in the family Pedaliaceae, the Martyniaceae have been allied to numerous other families within the order Lamiales. The objectives of this study include the investigation of the placement of the Martyniaceae within the order Lamiales using molecular data (chloroplast DNA sequences), the further examination of the internal relationships of the Martyniaceae using an expanded nuclear and chloroplast sequences data set, and the construction of a taxonomic treatment of the family that includes all published names and taxa in the Martyniaceae. An analysis of the Lamiales using two chloroplast gene regions (ndhF and rps16) reveals that the Martyniaceae should be segregated from the family Pedaliaceae, but is not able to support the placement of any of its putatively-related families as sister to the Martyniaceae. Sequences from 151 taxa of the Lamiales are included in the analysis, including six representatives from the Martyniaceae. An analysis of the Martyniaceae using three chloroplast gene regions (psbA-trnH spacer, trnQ-5'rps16 intergenic spacer, and trnS-trnG-trnG spacer and intron) and the Internal Transcribed Spacer resolves two major clades within the Martyniaceae corresponding to the North American taxa (Martynia and Proboscidea) and the South American taxa (Craniolaria, Holoregmia, and Ibicella). Sequences from all five genera and 15 taxa were included in the analysis. Results from the molecular phylogenetic analyses are incorporated into a revised taxonomic treatment of the family. Five genera and thirteen species are recognized for the family Martyniaceae. / Dissertation/Thesis / Ph.D. Plant Biology 2011
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Genome evolution and systematics of the Paenungulata (Afrotheria, Mammalia)Pardini, Amanda T. 12 1900 (has links)
Dissertation (PhD)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: Increases in taxonomic sampling and the numbers and types of markers used in
phylogenetic studies have resulted in a marked improvement in the interpretation of
systematic relationships within Eutheria. However, relationships within several clades,
including Paenungulata (Hyracoidea, Sirenia, Proboscidea), remain unresolved. Here the
combination of i) a rapid radiation and ii) a deep divergence have resulted in limited
phylogenetic signal available for analysis. Specifically i) a short internode separating
successive branching events reduces the time available for changes to occur, while ii) the
longer the time since divergence, the greater the opportunity for signal to be negatively
affected by homoplasy. This is evident in both molecular and morphological data where
an overall consensus on paenungulate relationships is lacking. Morphological analysis of
anatomical and fossil evidence favours the association of Sirenia (S) and Proboscidea (P)
(Tethytheria) to the exclusion of Hyracoidea (H); further, support for uniting these three
taxa as Paenungulata is contentious. In contrast, molecular data provide strong support
for Paenungulata but intra-ordinal relationships are ambiguous. Although results from
mitochondrial DNA sequence data favour Tethytheria, there is no consensus of support
for this clade from nuclear DNA. Nuclear DNA is typified by node instability but favours
H+P in the largest concatenation of sequences. Due to the expected increased effect from
homoplasy and consequently the increased likelihood for misleading signal, it is unclear
which result is most likely to represent the “true” tree.
An analysis of available and added intron sequences to characterise signal heterogeneity
among nuclear DNA and mitochondrial DNA partitions indicated that the phylogenetic
utility of partitions varies considerably. Subpartitioning of the data according to similar
evolutionary processes/characteristics (e. g., mtDNA vs. nDNA and codon position)
revealed new insights into the signal structure of the data set; specifically i) that nuclear
DNA first codon positions, and to a lesser degree second codon sites, provide convincing
support for H+P, and ii) that support for S+P by faster evolving sites within mtDNA
suggests that this may be the result of misleading signal. If H+P represents the “true
tree”, then support for this clade indicates that phylogenetic signal has been reduced over time as a result of multiple hits, which explains the presence of (hidden) support in
slower evolving sites where homoplasy is less likely to occur, in contrast to faster
evolving sites where no support for H+P was observed.
In an attempt to provide further resolution from an alternative perspective to that possible
with DNA sequence data, chromosomal rearrangements were identified among the three
paenungulate lineages. Using comparative chromosome painting, unique changes within
each order and specific to Paenungulata were characterised, however, intra-ordinal
synapomorphies were not recovered. Although this may suggest a hard polytomy, the
slow to moderate rate of evolution estimated from the data is likely not sufficient relative
to the rapid radiation associated with the paenungulate node. Further examination of
chromosomal rearrangements at a higher level of resolution may yet reveal informative
changes. / AFRIKAANSE OPSOMMING: ‘n Toename in die aantal taksonomiese monsters sowel as die aantal en soort merkers wat
in filogenetiese studies gebruik word, het tot ‘n merkbare verbetering in die vertolking
van sistematiese verwantskappe binne die Eutheria gelei. Desondanks bly ‘n aantal klades
(stamlyne), met inbegrip van Paenungulata (Hyracoidea, Sirenia, Proboscidea), steeds
onopgelos. By laasgenoemde het die kombinasie van i) ‘n vinnige radiasie en ii) ‘n diep
divergensie die filogenetiese sein wat vir analise beskikbaar is, beperk. Meer spesifiek sal
i) opeenvolgende vertakkings wat deur kort internodusse geskei word die beskikbare tyd
waartydens veranderings kan intree, verminder, terwyl ii) ‘n toename in tydsverloop
sedert divergensie die kans dat die sein deur homoplasie nadelig beïnvloed sal word,
vergroot. Dit word in sowel molekulêre en morfologiese data, waar ‘n oorhoofse
konsensus t.o.v. verwantskappe van Paenungulata ontbreek, waargeneem. Morfologiese
analise van anatomiese en fossielbewyse ondersteun die samevoeging van Sirenia (S) en
Proboscidea (P) (Tethytheria) ten koste van Hyracoidea (H). Ondersteuning vir die
samevoeging van dié drie taksa as Paenungulata is egter aanvegbaar. In teenstelling
hiermee word Paenungulata sterk deur molekulêre data ondersteun, al bly die
verwantstkappe op intra-orde vlak, steeds onduidelik. Alhoewel die resultate van
mitochondriale DNA op Tethytheria dui, word die klade nie deur data van kern-DNA
ondersteun nie. Kern-DNA word gekarakteriseer deur node instabiliteit maar verkies H+P
in die grootste samevoeging van geen volgordes. Na aanleiding van die verwagte
toename in die effek van homoplasie en die gevolglik groter kans op ‘n misleidende sein,
is dit nie duidelik watter van die resultate die meer korrekte filogenetiese stamboom
verteenwoordig nie.
Analise van beskikbare en nuut toegevoegde intron-volgordes om sein-heterogeniteit
tussen kern- en mitochondriale DNA verdelings te karakteriseer, toon dat die
filogenetiese nut van verdelings beduidend verskil. Onderverdeling van die data op grond
van soortgelyke evolusionêre prosesse/karaktereienskappe (bv. mtDNA vs. nDNA, en
kodonposisie) het na nuwe insigte in die seinstruktuur van die datastel gelei. Meer
spesifiek dat i) kern-DNA se eerste kodonposisies, en tot ‘n mindere mate die tweede kodonposisies, H+P oortuigend ondersteun en ii) dat ondersteuning vir S+P deur posisies
binne mtDNA wat vinnig verander, op ‘n misleidende sein mag dui. As H+P die korrekte
stamboom verteenwoordig dui ondersteuning vir die klade op ‘n filogenetiese sein wat
met verloop van tyd as gevolg van veelvuldige seinvoorkomste verklein het. Dit verklaar
die aanwesigheid van versluierde ondersteuning in stadig-veranderende posisies waar die
neiging tot homoplasie klein is, in teenstelling met posisies wat vinniger verander en
waar ondersteuning vir H+P nie waargeneem is nie.
Op soek na verhoogde resolusie vanuit ‘n ander perspektief as DNA-volgordebepaling, is
chromosomale herrangskikkings in die drie stamlyne van Paenungulata nagevors. Met
behulp van vergelykende chromosoomkleuring is unieke veranderings binne elke orde en
spesifiek binne Paenungulata gekarakteriseer, maar geen sinapomorfe kenmerke is op die
intra-orde vlak gevind nie. Alhoewel dit op ‘n onopgeloste politomie mag dui, is die
stadige tot matige evolusietempo wat van die data afgelei word, relatief tot die vinnige
radiasie wat met die Paenungulata-nodus geassosieer word, waarskynlik onvoldoende vir
‘n oplossing. Verdere navorsing oor chromosomale herrangskikkings met ‘n hoër
resolusievlak mag addisionele insiggewende veranderings aantoon.
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The American Mastodon (<i>Mammut americanum</i>) at Wittenberg UniversityChatfield, Evie 03 August 2023 (has links)
No description available.
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