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Gorgonocephalus eucnemis, Ophiothrix suensonii and Ophiothrix spiculata are aerobic Echinoderms. Previous observations on the anatomy of these two genera state five pairs of radial shields and genital plates are responsible for regulating the position of the roof of the body disc and the flushing of water in and out of the bursae. Rates of bursal ventilation increase by an average 60-64% when the ophiuroid is exposed to an increase in food or a decrease in dissolved oxygen in Gorgonocephalus. When exposed to hypoxic oxygen concentrations O. suensonii and O. spiculata increased bursal-ventilation rates by (means of) 35% and 28%. Measurements of DO from inside and outside the bursae show that DO is being absorbed during bursal-ventilations. These findings suggest bursal ventilation is a means of respiration and increased rates of bursal-ventilation may help meet increased oxygen demands during feeding and some periods of hypoxia. This dissertation includes unpublished, co-authored material.

Yes / Background: Carbon (δ13C) and nitrogen (δ15N) isotope ratios of collagen from teeth and bone are used to study human nutrition and health. As bones are constantly remodelling throughout life, isotopic values of bone collagen represent an average of several years. In contrast, human teeth do not remodel and their primary dentine contains only the isotopic data from the time of formation. In contrast to all other bones, human auditory ossicles also appear not to remodel. As they develop in utero and finish formation in the first 2 years of life, their collagen should also represent isotopic values of these two relatively short periods. Aim: By comparing δ13C and δ15N data from ossicles and incremental dentine, this study aims to investigate how two developmental periods of the ossicles, in utero and the first 2 years of life, reflect in collagen obtained from the ossicles. Subject and methods: Ossicle and tooth samples of 12 individuals aged 0.5 ± 0.4 years to 13 ± 1 years from the nineteenth century St. Peter’s burial ground in Blackburn were collected and processed to obtain bulk bone and incremental dentine collagen which was measured for δ13C and δ15N. Results: Averaged δ13C and δ15N of ossicles are lower when compared to every age group except after 3 years of age. Average offset between ossicles and dentine of different groups ranges from 0.4–0.9‰ for δ13C and from 0.3–0.9‰ for δ15N, with highest counterbalance at birth and after the first 5 months after birth. Conclusions: There appears to be a systematic offset between the dentine and ossicle data. It seems that the second phase of development does not influence the isotopic values of collagen significantly and the data we are obtaining from ossicles represents the in utero period. / Research grant from The Society for the Study of Human Biology.

Atualmente a ordem Dendrochirotida é composta por 800 espécies, sendo que metade destas estão entre as famílias Sclerodactylidae e Phyllophoridae. Todavia, a maior parte das informações acerca dos seus táxons é proveniente de revisões morfológicas muito antigas (Phyllophoridae em 1954, e Sclerodactylidae não revisada). Este estudo, portanto, se configura como o primeiro teste formal da monofilia das famílias Sclerodactylidae e Phylllophoridae e suas subfamílias. O presente trabalho constitui um estudo morfológico minucioso das estruturas que compõem o endoesqueleto dos Holothuroidea que são os ossículos dérmicos e anel calcário, vislumbrando alcançar através de uma análise cladística os objetivos descritos a seguir: (i) testar a monofilia de Phyllophoridae; (ii) testar a monofilia de Sclerodactylidae; (iii) testar a monofilia das subfamílias de Phyllophoridae e (iv) testar a monofilia das subfamílias de Sclerodactylidae. O material estudado foi obtido a partir de visitas e/ou empréstimos de museus nacionais e internacionais. Foram estudados espécimes de todas as ordens de Holothuroidea, à exceção de Elasipodida, totalizando 956 espécimes pertencentes a 78 espécies, das quais quatro foram delimitadas como grupo externo (i.e. Aspidochirotida, Apodida e Dendrochirotida [Cucumariidae e Psolidae]) e 44 delimitadas como grupo interno (todas as espécies tipo foram analisadas). Setenta e dois caracteres foram descritos e ilustrados através de fotografias ou microscopia eletrônica de varredura. As análises foram realizadas com o programa PAUP (v. 4.0), através do algoritmo de parcimônia Tree Bissection and Reconnection (TBR) de branch-swapping, com 5000 réplicas. O estudo morfológico detalhado permitiu elencar novos caracteres, bem como reinterpretar caracteres já estabelecidos, além de fornecer correções de interpretações equivocadas acerca de tais estruturas. Sclerodactylidae foi recuperada como monofilética e está composta por três subfamílias (todas foram recuperadas como monofiléticas), Clado I, Sclerodactylinae e Thyoninae. Phyllophoridae foi recuperada como monofilética e está composta por três subfamílias (todas foram recuperadas como monofiléticas), Cladolabinae, Phyllophorinae e Semperiellinae. / Currently, the order Dendrochirotida comprises about 800 species, half of these being within the families Sclerodactylidae and Phyllophoridae. Regardless, most information about these families is from old morphological revisions (Phyllophoridae in 1954 and Sclerodactylidae not reviewed). This study appears as the first formal test of the monophyly of the families Sclerodactylidae and Phylllophoridae and their respective subfamilies. The present work constituted a detailed morphological study of the structures that compose the Holothuroidea endoskeleton which are the dermal ossicles and calcareous ring to achieve through a cladistic analysis the following objectives: (i) to test the monophyly of Phyllophoridae; (ii) to test the monophyly of Sclerodactylidae; (iii) to test the monophyly of the Phyllophoridae subfamilies and iv) to test the monophyly of the subfamilies of Sclerodactylidae. The material studied was obtained from visits and/or loans from the national and international museums. Specimens of all orders of Holothuroidea were analyzed with the exception of Elasipodida, yielding 956 specimens belonging to 78 species, of which four were delimited as outgroups (i.e. Aspidochirotida, Apodida and Dendrochirotida [Cucumariidae and Psolidae]) and 44 delimited as internal groups (all type specimens were analyzed). A total of 72 morphological characters were described and illustrated through photographs or scanning electron microscopy images. The analyses were conducted with the aid of PAUP (v.4.0) using a parsimony algorithm Tree Bisection and Reconnection (TBR) branch-swapping (5000 replicates). This detailed morphological study allowed us to list new characters, to reinterpret. already established ones as well as providing corrections of misinterpretations about such structures. Sclerodactylidae was recovered as monophyletic and is composed of three subfamilies (all were recovered as monophyletic), Clade I, Sclerodactylinae and Thyoninae. Phyllophoridae was recovered as monophyletic and consists of three subfamilies (all were recovered as monophyletic), Cladolabinae, Phyllophorinae and Semperiellinae.

Acoustically, teleost swimbladders have been considered resonant underwater bubbles. Contrary results indicating that bladders are tuned less sharply than such a bubble have been explained by damping of surrounding fish tissue. Recent findings in toadfish and weakfish, however, suggest that the bladder is a highly damped structure and that the frequency of the fish sounds is deternlined as a forced response to sonic muscle movement rather than by resonance of the bladder. In this study I examined acoustics and material properties of swimbladders in Tilapia (an auditory generalist) and the channel catfish (an auditory specialist). The swimbladder was struck with a piezoelectric impact hammer. Amplitude and timing characteristics of bladder sound and displacement were compared for strikes of different amplitudes. Most of the first cycle of sound occurs during swimbladder compression, indicating that the bladder rapidly contracts and expands as force increases during the strike. Harder hits are shorter in duration generate a similar displacement duration with an increasing number of shorter cycles and a 12-15 dB increase in sound amplitude. The frequency spectrum is broad, and the dominant frequency is driven by the strike and not the natural frequency of the bladder. The displacement waveform varies between species catfish exhibit a greater structural stiffness and lower amplitude movement and higher sound amplitude for an equivalent hammer strike. Material properties (peak load, stress, strain, Young's modulus), fiber direction (catfish only), and structural stiffiless of bladders exhibit various patterns suggesting that the bladder walls are not uniform structures. Additionally thickness varies regionally. Notably Young's modulus in both species is similar despite large difference in stress and strain. The modulus of catfish bladder increased 1600-fold when dried. Finally the bladder of both species had a high water content averaging about 70%. These data suggest that viscous damping caused by water in the bladder wall is a major factor responsible for acoustic properties of the teleost swimbladder.

Innerhalb der Decapoda stellt das Taxon Brachyura eines der artenreichsten Taxa mit bis zu 10000 Arten dar. Die Phylogenie der Brachyura wird aufgrund morphologischer und molekularer Untersuchungen seit mehr als ein Jahrhundert kontrovers diskutiert. Zur Klärung phylogenetischer Fragestellungen wurde mit den vergleichenden Untersuchungen der Magenossikel und der Magenzähne von 66 Taxa der Brachyura ein neuer phylogenetischer Ansatz gewählt. Mit Anwendung eines spezifischen Färbepigmentes, Alizarin-Rot S, konnten sechs neue Magenossikel einer bereits existierenden Nomenklatur hinzugefügt werden, so dass jetzt 41 Magenossikel für das Grundmuster der Brachyura angenommen werden können. Im Ergebnis der phylogenetischen Analyse wird ein monophyletisches Taxon Brachyura einschließlich der Taxa Dromiidae und Raninidae unterstützt. Die von Guinot (1977, 1978) als Monophyla postulierten Teiltaxa Podotremata und Heterotremata finden hier keine Unterstützung. Taxa wie Raninidae und Cymonomidae, welche aufgrund der coxalen Position ihrer Genitalporen dem Taxon Podotremata sensu Guinot zugeschrieben werden, weisen nach vorliegenden Daten eine nähere Verwandtschaft zu den "höheren" Krabben auf. Eine Monophylie eines Taxons Thoracotremata sensu Guinot kann dagegen basierend auf den analysierten Magenstrukturen, aber auch auf der Grundlage molekularer Studien (Schubart et al. 2000a, 2000b) und dem vorliegenden Daten zum Fossilbericht angenommen werden. Eine basale Stellung der Dynomenidae und Dromiidae im Ergebnis der kladistischen Analyse lässt sich mit den Fossilfunden aus dem mittleren Jura in Übereinstimmung bringen. Des weiteren kann für die meisten Taxa der "höheren" Krabben ein gemeinsamer Vorfahre für die obere Kreide bzw. bis zum Beginn des Tertiärs postuliert werden. / Within the Decapoda the taxon Brachyura is the species-richest taxon with up to 10000 species. The phylogeny of the Brachyura has been discussed based on morphological and molecular investigations since more than a century. The investigation of the foregut-ossicles and gastric-teeth of 66 brachyuran species, is a new approach to answer important phylogenetic questions. Using a specific staining pigment Alizarin Red S, six new described foregut-ossicles are added to an existing nomenclature. As a result of this method the presence of 41 foregut-ossicles is proposed for the ground pattern of the Brachyura. The cladistic analysis supports a monophyletic origin of the Brachyura including the Dromiidae and the Raninidae. The taxa Podotremata and Heterotremata, postulated as monophyletic by Guinot (1977, 1978), are not supported in the present study. The Dromiidae and Raninidae, which are placed within the Podotremata sensu Guinot, are closer related to the "higher crabs". Based on the analysed foregut-characters, several molecular studies (Schubart et al. 2000a, 2000b), and the data of the fossil record, a monophyletic origin of the Thoracotremata sensu Guinot is suggested. The analysed basal position of the Dynomenidae and Dromiidae is in agreement with the brachyuran fossil record. A common ancestor for most of the "higher" brachyuran crabs is suggested for the period between the upper Cretaceous and the beginning of the Tertiary.

In order to get a better insight into the function of the human middle ear it is necessary to simulate its dynamic behaviour by means of the finite-element method. Three-dimensional measurements of the surfaces of the tympanic membrane and of the auditory ossicles malleus, incus and stapes are carried out and geometrical models are created. On the basis of these data, finite-element models are constructed and the dynamic behaviour of the combinations tympanic membrane with malleus in its elastic suspensions and stapes with annular ligament is simulated. Natural frequencies and mode shapes are computed by modal analysis. These investigations showed that the ossicles can be treated as rigid bodies only in a restricted frequency range from 0 to 3.5 kHz. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

In order to get a better insight into the function of the human middle ear it is necessary to simulate its dynamic behaviour by means of the finite-element method. Three-dimensional measurements of the surfaces of the tympanic membrane and of the auditory ossicles malleus, incus and stapes are carried out and geometrical models are created. On the basis of these data, finite-element models are constructed and the dynamic behaviour of the combinations tympanic membrane with malleus in its elastic suspensions and stapes with annular ligament is simulated. Natural frequencies and mode shapes are computed by modal analysis. These investigations showed that the ossicles can be treated as rigid bodies only in a restricted frequency range from 0 to 3.5 kHz. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Pour bien comprendre comment les espèces actuelles ont évolué, il est important d’étudier certains groupes clés. Ces groupes clés sont parfois bien négligés au profit d’autres groupes apparentés. L’embranchement Hemichordata forme, avec Echinodermata, le clade Ambulacraria. Ce dernier, avec l’embranchement Chordata, forme le super-embranchement Deuterostomia. Parmi les deutérostomes, la classe d’hémichordé Enteropneusta est souvent considérée comme étant la plus ressemblante au dernier ancêtre commun des deutérostomes. Les entéropneustes partagent en effet plusieurs caractéristiques avec Chordata et Ambulacraria et en étudiant celles-ci on peut reconstruire et comprendre leurs états ancestraux. Dans le chapitre d’introduction, j’aborde la morphologie générale des hémichordés et leurs relations évolutives avec les deux autres embranchement deutérostomes. Je présente aussi les caractéristiques qu’ils partagent avec les échinodermes et les cordés. J’aborde ensuite les formes que prennent les parties dures chez les animaux et en particulier chez les deutérostomes. Dans le chapitre deux, j’examine et décris la forme et la composition chimique des osselets chez huit espèces d’hémichordé. Cette étude représente un énorme bond dans nos connaissances sur la biominéralisation chez les hémichordés, car jusqu’à présent les osselets n’avaient été décrits que chez deux espèces, et la composition chimique déterminée chez une seule d’entre elle. J’interprète également ces données dans un contexte évolutif, car les osselets d’hémichordé sont probablement homologues au squelette des échinodermes. Ce chapitre est important, car il nous donne une hypothèse sur l’origine des osselets chez le dernier ancêtre commun des ambulacraires. Dans le chapitre trois, je quantifie l’asymétrie dans les fentes pharyngiennes de populations de deux espèces d’entéropneustes et d’une espèce de cordé non-vertébré. En mettant ces différents nivaux de symétrie en parallèle avec leur comportement alimentaire, les résultats supportent l’hypothèse de l’alimentation par filtration comme rôle initial des fentes pharyngiennes chez les deutérostomes et que la perte de cette fonction induit du bruit développemental, une vestigialisation ou une perte des fentes branchiales. Dans le chapitre quatre, J’utilise la micro-tomographie aux rayons-X pour décrire une espèce d’hémichordé qui était jusqu’à présent un numen nudum. Cette nouvelle technique est comparée avec l’histologie traditionnelle afin de prouver qu’elle pourrait être utilisée dans les futures études taxonomiques sur les hémichordés. Dans le chapitre cinq, je présente quelques expériences qui ont dû être exclues des chapitres précédents car elles ont donné des résultats négatifs non-publiables. Je discute des raisons pour lesquelles ces expériences ont échoué ainsi que quelques pistes de solutions possibles pour qui voudrait tenter de les refaire. Ensuite je récapitule les résultats des chapitres précédents pour montrer comment étudier les hémichordés peut encore nous apprendre beaucoup sur d’autres groupes pourtant déjà très étudiés. / The phylum Hemichordata forms, with Echinodermata, the group Ambulacraria that in turns forms with Chordata, the Deuterostomia. Among deuterostomes, the hemichordate class Enteropneusta is often viewed as the group that most closely resembles the last common ancestor of deuterostomes. Enteropneusts indeed share many traits with the other two deuterostome phyla and by studying them, we can infer the ancestral states of those traits. In the first chapter, I present the general morphology of hemichordates and their relationships with the other two deuterostome phyla. I also discuss the shared traits between the hemichordates, the echinoderms and the chordates. Last, I present the varied shapes that hard parts can take in animals, with a focus on deuterostomes. In chapter two, I describe the shape and mineral composition of ossicles in eight enteropneust species. This study is a major leap in our understanding of biomineralization in Hemichordata since up to this point ossicles were only described in two species and the mineral composition determined for only one. I discuss these results in an evolutionary context since hemichordate ossicles are probably homologous with echinoderm skeletal ossicles. This chapter is significant because it provides a hypothesis on the origin of ossicles in the last common ancestor of ambulacrarians. In chapter three, I quantify the level of asymmetry of the pharyngeal slits in populations of two species of enteropneusts and the invertebrate cephalochordate Branchiostoma floridae. We found that adults of these species display fluctuating asymmetry in the gills and that this asymmetry is lower in filter feeding. This is significant because it supports the hypothesis that filter feeding is an ancestral feature of deuterostomes and that the loss of this function increases developmental noise, vestigiality, or loss of the gills. In chapter four, I use X-ray microtomography to describe the enteropneust Balanoglossus occidentalis that was heretofore a nomen nudum. This new technique is compared with traditional histology to show that it is a viable tool in hemichordate taxonomical studies. In chapter five, I present a few experiments that had to be excluded from the other chapters because they gave negative, unpublishable results. I discuss the probable causes of their failures and potential ways to solve these issues for those who would want to pursue them further. Finally, I summarise the results of the previous chapters to show how studying hemichordates can still teach us a lot about the origin and evolution of the better studied deuterostome phyla.