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    The shape of penguins in four dimensions : assessing macroevolutionary shifts in a constructional morphology framework : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology at Massey University, Albany Campus, New Zealand
    (Massey University, 2022) Giovanardi, Simone
    Describing the morphology of a clade through deep time provides rich insight into the drivers that shaped modern diversity. It is in this context that Adolph Seilacher developed the constructional morphology concept, in order to describe which are the major pressures acting on an organism's morphological appearance. The three components or apices of constructional morphology are the evolutionary history of the organism, the constraints placed on the structure, and the opportunity provided by adaptation. The structure of this thesis is based on the constructional morphology concept with each chapter focusing on the impact of each of the three components of constructional morphology with the scope to provide a novel approach to quantify morphological macroevolution. After introducing concepts of constructional morphology, geometric morphometrics and Bayesian statistics in Chapter 1, Chapter 2 presents an analysis to estimate the historical apex: a phylogenetic analysis based on the synthesis of previous published matrices, as well as a description of the giant fossil penguin Kairuku waewaeroa. The resulting phylogenetic tree indicates that the penguin evolutionary history was characterised by many monophyletic large groups that challenges previous results and indicate that the body plan of extinct penguins could be more diverse than previously thought. Chapter 3 focused on the structural apex, aiming to provide a generalisable Bayesian approach to estimate the size of extinct giant penguins in the context. By measuring the total volume of the femur and the humeral articular facet of the coracoid it was possible to generate two sets of models that together provided novel evidence in favour of reduced body mass estimates for giant penguins when compared with prior published estimates. Moreover, although the two sets of estimates are derived from two distinct features, the body mass estimates from the two models tend to converge, providing confidence in the accuracy of the Bayesian-informed method. Chapter 4 presents and investigation into the impact of adaptation on two separate locomotory modules, the humerus and the tarsometatarsus, using 3D geometric morphometric techniques. Comparing morphological rates of change reveals a steady rate decrease in the humerus and more heterogeneous rates for the tarsometatarsus. Similar results are obtained by estimating the morphospaces for humeri and tarsometatarsi from hypothetical ancestors using a penalized likelihood approach. The synthesis that this constructional morphology framework approach provides highlights the important relationship between shape and size, showing how size can be a driver of morphological innovation. More importantly, the results of this thesis highlight the relevance that constructional morphology still has today, and how it can be integrated into palaeontology and evolutionary biology studies through the use of advanced statistical techniques. A constructional morphology approach is not solely applicable to penguins and may be extended to a broad range of groups of organisms, contributing thus to better understand the underlying forces that shaped the origins of modern biota.
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    Evolution and stable isotopes in Placostylus species of the southwest Pacific : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology, Massey University, New Zealand
    (Massey University, 2021) Quenu, Mathieu
    Human activities during the Holocene have induced a sixth biodiversity crisis and initiated rapid changes in the climate. The anthropogenic pressures put on ecosystems can result in direct or indirect environmental degradation, fragmentation and defaunation. Understanding local patterns of wildlife population structure, species interactions and initial biodiversity are all crucial to making well-informed decisions that leads to population sustainability and conservation of global biodiversity. This thesis is focused on the genus of giant land snail Placostylus and seeks to improve our overall knowledge of the genus and its potential to store information about the local environment (such as temperature and humidity) during shell formation. Placostylus is a genus endemic to the southwest Pacific and the many species present a valuable opportunity to integrate studies of ecology and environment at a scale relevant to current anthropogenic climate change. The characteristics of Placostylus shells can be used to investigate extant and extinct morphological variation within the genus, and their chemical composition can be used to track the environmental conditions in which the snails lived. In parallel to shell analysis the generation of genetic data can be used to infer phylogenetic relationships between distant taxa, and at a fine-scale patterns of population structure allow us to infer gene flow and differentiation. Understanding the extent to which shell shape and size is controlled by genetic differences and how much phenotypic plasticity leads to differences is essential if we are to correctly interpret the significant of phenotypic variation. For example, arid conditions can lead to Placostylus snails maturing when much smaller in size. Potentially, intraspecific shell shape and size variation and shell chemistry can all inform us about the local environmental conditions that existed as snail shells were formed. Three main axes are developed throughout the thesis. First the diversity of Placostylus and extended species of the super-family Orthalicoidea are introduced using a phylogenetic investigation. Evolutionary relationships are inferred from DNA sequences of mitochondrial and nuclear genetic datasets. Second, morphological variation is examined in detail where two Placostylus snail species are sympatric (the Isle of Pines, New Caledonia). The variation in shell shape of taxa living and growing in the same environment must represent genetic differences rather than phenotypic plasticity. However, genetic data from the Placostylus species present on the Isle of Pines was needed when a third snail morphotype was discovered. On the Isle of Pines giant land snails of the species P. fibratus are harvested for food, where iii they are sympatric with the vulnerable species P. porphyrostomus. Understanding local population structure of both species and their interaction will inform management decisions for both species. Third, the stable isotopic composition of extant Placostylus shells is analysed from Placostylus shells from New Zealand and New Caledonia. This works has the aim to establish a climate proxy system which through the analysis of fossil shells could inform us about past environmental conditions. A protocol to sample high-resolution isotopic signatures from Placostylus shells is developed and the stable isotopic composition of shells are examined in light of the environmental variables of the snail collection locations.
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    Genetic and phenotypic variation used to identify populations of endangered green gecko (Naultinus) found in the north-west South Island, New Zealand : a thesis submitted in fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Albany and Palmerston North. EMBARGOED until further notice.
    (Massey University, 2018) King, Samantha J.
    Two species of green gecko (Naultinus stellatus and Naultinus tuberculatus) found in the north and west South Island are endemic to New Zealand and are classified as Nationally Vulnerable (Hitchmough et al. 2016). Detailed information about the ecology, morphology and distribution of these geckos is limited, including what traits are diagnostic, details of their geographic range and it is unknown whether both species hybridise in the wild. My research aimed to investigate if the Denniston and Stockton Plateaus in New Zealand’s South Island represent a putative contact zone between N. stellatus and N. tuberculatus and if natural hybridisation occurs. Naultinus species are known to reproduce with each other in captivity and a few wild caught individuals (n=5) have led to an inference of introgressive hybridisation. In addition, I aimed to collect basic data on the ecology and morphology of both species and a putative hybrid to determine the extent of inter and intraspecific variation in phenotypic traits. I did not find evidence of a contact zone or hybridisation occurring between N. tuberculatus and N. stellatus; all geckos sampled in this study from Denniston and Stockton plateaux were morphologically and genetically part of N. tuberculatus. My results show significant intraspecific phenotypic variation between populations for each species. For example, body colour patterns of some populations are more similar between species than within. However, concordance between genetic markers and colour combinations of mouth and tongue provided evidence of clear species differences, and traits to distinguish the species, despite intraspecific variation of other traits. Finally, I recorded detailed habitat parameters for each individual and documented variation in perch height, both within populations and between sex. This information helps conservation practitioners to implement best practice techniques for green gecko conservation management by determining ecotypes and habitat use, population variance, which can prevent the further decline of both genetic variation and risk to species. Specifically, this research aids the mitigation of negative impacts by mining operations and development, such as is the current threat to the Denniston and Stockton plateaux.--Shortened abstract
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    Assessing the effect of plant surface on the predatory ability of Orius vicinus : a potential biological control agent of the tomato-potato psyllid (Bactericera cockerelli) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand
    (Massey University, 2019) Gamarra Landa, Abel
    The tomato-potato psyllid (TPP), Bactericera cockerelli (Sulc), is a pest to solanaceous crops (e.g. potato, tomato, peppers, and eggplant) and is associated with economically important plant diseases. Subsequently, chemical control is the preferred management option. However, chemical reliance is associated with a host of issues. The development of biological control methods is vital to implementing Integrated Pest Management (IPM) programs as an alternative to broad-spectrum insecticide usage. The predatory bug Orius vicinus (Ribaut) is a potential biological control agent that is capable of consuming all nymphal life stages of TPP. In order to be a commercially viable management option, potential biological control agents of TPP have to cope with the different morphological plant features of the pest’s wide range of host plants. Tomato and capsicum plant surfaces were selected as the experimental surfaces for my thesis because they differ significantly in their substrate morphology. Tomato plant surfaces can be a hostile environment for potential biological control agents due to the negative effect tomato trichomes have on their foraging performance. Alternatively, because capsicum plant surfaces are virtually void of trichomes they appear to be more suitable for effective biological control agent deployment. I exposed the predatory bug to a variety of TPP nymph densities (10, 20, 30 and 40 individuals) in order to determine the functional response of O. vicinus. Furthermore, the predatory bug was exposed to all five TPP nymphal stages simultaneously. The predatory performance of O. vicinus was also assessed on experimental arenas varying in complexity (leaflet vs. small plant environments). The functional response was determined to be Type II on both plant surfaces. Nymph consumption at higher prey densities (30 and 40 nymphs) was significantly greater on capsicum than on tomato. Nymph consumption at lower prey densities (10 and 20 nymphs) was only significantly greater on capsicum when the complexity of the experimental arena increased from leaflet to small plant. The influence of O. vicinus in nymph dispersal was also assessed. My results revealed that the presence of O. vicinus increased the dispersal of nymphs to lower leaf surfaces and that nymph dispersal was significantly greater on capsicum than on tomato. TPP nymph size preference by O. vicinus was determined in my study. I established that the predatory bug is capable of killing all nymphal stages. My study strongly indicated that the predatory bug is more likely to target and consume medium (3rd instars) and large nymphs (4th and 5th instars) over small nymphs (1st and 2nd instars). I investigated the behaviour of O. vicinus adults and TPP nymphs during their interactions via video recordings. The predatory bug spent a significantly greater amount of time investigating TPP nymphs on capsicum than on tomato. There was significantly higher number of attacks recorded on capsicum. The greater killing percentage on tomato suggests that the defensive capabilities of TPP nymphs appear to have been negatively affected by the tomato substrate. The results from my study indicate that augmentative releases of O. vicinus, in the presence of smaller TPP nymphs, could be a viable biological control option on capsicum plants. However, the predatory bug will likely struggle if deployed on tomato plants. Future studies should be conducted in settings such as open field or glasshouses using multiple predatory bugs in the presence of susceptible life stages to assess augmentative release efficiency.
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    Evolution of the spherical cell shape in bacteria : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany, New Zealand
    (Massey University, 2019) Yulo, Paul Richard Jesena
    Cell shape is an important feature of bacterial cells. It is involved in critical aspects of bacterial cell biology such as motility, growth, and the evasion of predators. Despite this, how cell shape has evolved in bacteria is unclear. For most rod-shaped bacteria, the maintenance of cell shape depends primarily on the bacterial actin-like protein, MreB. In this study, we show that the deletion of MreB from the rod-shaped model organism Pseudomonas fluorescens SBW25 results in the formation of aberrant spherical cells that have increased size and reduced fitness. This new MreB-null strain (ΔmreB) is susceptible to mechanical damage and grows poorly due to cell division defects. Furthermore, synthesized peptidoglycan (PG) chains were shorter and cell wall assembly was disorganised in this strain. A 1,000-generation evolution experiment comprised of multiple independent lineages produced spherical cells that have a reduced cell size and improved fitness. Mutations in the PG synthesis protein PBP1a were found across multiple lineages. Genetic reconstructions demonstrated that these mutations have a loss-of-function effect that reduced PG cross-linking and restored the ordered assembly of the cell wall, thereby reducing cell size and improving fitness in MreB-null cells. In one lineage, a five-gene deletion that included the gene coding for the outer membrane channel OprD was found to be beneficial. This deletion reduced cell size, improved fitness, and restored orderly cell wall construction. The mechanism responsible for this is unknown, but it may be related to modifications in septum localisation via the Min system. Finally, we show using phylogenetic analysis that PBP loss is a general trend in bacteria that evolved to become spherical, hinting at a plausible strategy for the evolution of the spherical cell shape from rod-shaped progenitors.
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    The genetic architecture of the divaricate growth form : a QTL mapping approach in Sophora (Fabaceae) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Biology at Massey University, Manawatu, New Zealand
    (Massey University, 2019) Pilkington, Kay
    Divarication is a plant growth form described, in its simplest form, as a tree or shrub with interlaced branches, wide branch angles and small, widely spaced, leaves giving the appearance of a densely tangled shrub. This growth form is a unique feature in the New Zealand flora that is present in ~ 10% of the woody plant species, a much higher frequency than that of other regional floras. While several hypotheses have been developed to explain why this growth form has evolved multiple times within New Zealand, to our knowledge, no work has addressed the genetic basis of the divaricating form. Sophora is one of several genera in New Zealand that possesses divaricate species. Among the factors making this an ideal system for a genetic investigation of divarication is an existing F₂ population formed from reciprocal crosses between the divaricating S. prostrata and the non-divaricating S. tetraptera. Using this segregating population and newly developed molecular markers, the first linkage maps for Sophora were generated, providing a new genetic resource in Sophora. These linkage maps allowed for quantitative trait locus (QTL) mapping for traits associated with the divaricate form in the segregating population. Multiple QTL were mapped to seven of the divaricate traits with many QTL co-locating for multiple traits, indicating that the divaricate growth form is genetically controlled by many loci, potentially including pleiotropic loci, that each contribute to the overall divaricate phenotype in Sophora. The strigolactone biosynthesis and perception pathway is a good candidate for involvement in control of the divaricate form based on mutant phenotypes in Pisum that display similarities to the divaricate growth form, such as increased branching, shorter plant height and smaller leaves. QTL, for multiple traits, were mapped to two candidate genes investigated, RMS1 and RMS4. An amino acid replacement was identified in RMS1, in S. prostrata, that is predicted to be deleterious suggesting it may be non-functional in S. prostrata. These results support RMS1 as a strong candidate gene for future work on divarication. This study is the first to investigate the genetic architecture of the divaricate growth form and contributes to further understanding of this unique feature in the New Zealand flora and of plant architecture generally.
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    The roles of morphology, individuality and arrival from migration in the foraging ecology of bar-tailed godwits at the Manawatū River estuary : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University, Manawatū, New Zealand
    (Massey University, 2018) Ross, Tobias Alexander
    Bar-tailed Godwits (Limosa lapponica baueri) are a hugely size-variable shorebird exhibiting reverse sexual dimorphism as well as substantial variation within the sexes. This variation is especially pronounced in bill lengths, and differences in bill size could result in dietary differences between individuals. I studied the foraging ecology of individually-marked godwits at the Manawatū River Estuary in New Zealand, a small site amenable to making repeated observations of birds by videography. Specifically, I investigated the effects of bill size variation on intake rates and diet composition of godwits and tested for individual specialisation. Birds were found to use prey-specific foraging modes, the effect of which far outstripped that of any morphological or environmental factor. I found that shorter-billed birds (males) had slightly higher and less variable intake rates than their longer-billed (female) counterparts. The shorter-billed birds focused their efforts on catching small surface prey such as Potamopyrgus, to the extent where around half of the males specialised on these small snails. In comparison, longer-billed birds ate a more diverse array of prey items, notably consuming more worms which were buried deeply in the sediment. In addition to some birds specialising on certain prey, other prey were taken preferentially by only certain individuals across the size spectrum. This suggests that the diets of godwits are not only influenced by morphology but also by individual preferences of the birds themselves. I also tested for a carry-over effect of prolonged flight on foraging performance of godwits. The 8–10-day post-breeding migratory flight of godwits direct from Alaska to New Zealand is the longest known endurance flight of any land-bird. This flight has many expected physiological impacts, including a reduction in digestive tract mass that could lead to lower functionality of the digestive tract and therefore limit intake rates after arrival. By monitoring the daily occurrence of marked birds I determined when birds arrived on migration, and tested whether intake rates and diet choice changed in the fortnight after birds arrived. I found that intake rates were slightly higher and less variable with time since arrival. Furthermore, there was an increase in the consumption of the hard-shelled mud snail Amphibola crenata with time, suggesting a recovery of gizzard mass. Given the scale of the migration, however, these effects were surprisingly small and imply that diet choice and energy intake are affected only slightly by a physiological carry-over effect from migration.
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    Integrating species distribution models, genetics and morphology to infer species dynamics of New Zealand Phaulacridium grasshoppers : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Zoology at Massey University, Palmerston North, New Zealand
    (Massey University, 2016) Sivyer, Louisa Maree
    Species comparison studies have used a number of different methods that can contribute to our understanding of processes that influence the differences and similarities observed between species. This thesis describes the geographic distribution, spatial genetics, and morphology of two New Zealand Phaulacridium grasshoppers, the widespread P. marginale and the restricted P. otagoense. The primary focus was on Phaulacridium populations from the region of the southern South Island where the two species ranges overlap, for the purpose of examining the evolutionary and ecological interactions of the species. The geographic distribution of the two species was analysed using the recorded and potential modern distribution of Phaulacridium grasshoppers. Models of environmental envelopes for each species demonstrated that the potential distribution of P. marginale covered the majority of New Zealand. In contrast, the potential distribution of P. otagoense is restricted to patches of land primarily in the southern South Island where this species is known to occur. The phylogeographic structure of Phaulacridium species was analysed using dense population samples. Two main mtDNA COI sequence groups were found, one was shallow but geographically widespread, while the other was more diverse but geographically restricted. Within the southern South Island region both mitochondrial lineages co-occur within a single location. Demographic history analysis suggested that the widespread range of P. marginale is the result of recent population, and the restricted P. otagoense was recently represented in large populations. The morphological variation of Phaulacridium grasshoppers was explored using traditional and geometric techniques. Two distinct morphotypes were apparent, the larger morph was geographically widespread and the smaller morph was restricted to the southern South Island. Both morphotypes co-occur in locations within the southern South Island region. Furthermore, several individuals could not be classified into a discreet morphotype, suggesting that these individuals had a mixture of morphological features, as expected of a hybrid. Comparing the morphological and genetic data from the current study demonstrates the first reported case of introgression between P. marginale and P. otagoense. It is evident that Phaulacridium F1 hybrids exist in the wild, however it is unknown whether these F1 hybrids are fertile and also if F2 hybrids (backcrossed from parental species or F1 hybrids) are viable and fertile.
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    Population fragmentation in the small-scaled skink (Oligosoma microlepis) : the consequences of human landscape transformation on a habitat specialist's distribution, morphology, and genetics : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Manawatu, New Zealand
    (Massey University, 2012) Nelson-Tunley, Moniqua
    The endemic small-scaled skink (Oligosoma microlepis) is restricted to the central North Island of New Zealand. Strong preference for exposed rock piles, a relatively rare habitat, has created a fragmented distribution and restricted subpopulation sizes. The Department of Conservation lists the species as in serious decline, with IUCN listing it as vulnerable. At the stronghold of this species in the southern part of its range, subpopulations exist on small rock piles separated by up to 11 km of pastureland. Scattered northern subpopulations are separated by more than 19 km. These distances may act as dispersal barriers, as might the lack of refugia between subpopulations on pastureland. Lack of migration between subpopulations could reduce genetic diversity and increase inbreeding. Reduced genetic diversity could decrease resistance to disease, parasitism and environmental change, whereas inbreeding may reduce fertility, lifespan and juvenile survival. This thesis used a combination of survey data, morphological measurements and population genetics to investigate potential causes and consequences of population fragmentation on the small-scaled skink, with the aim of providing information to guide the long-term conservation of this species. A survey of known small-scaled skink subpopulations was conducted to determine if the species is in decline. In addition, potential small-scaled skink habitat was searched, including previously surveyed sites. Evidence of decline was inconclusive, with three subpopulations appearing to be in decline and discovery of five new subpopulations. Genetic (16S mitochondria and microsatellites) and morphological analysis was used to examine subpopulation differences in relation to species distribution, including investigating inbreeding within subpopulations. Relatedness between subpopulations was consistent with isolation by distance, indicating that small-scaled skink dispersal is limited by distance, but not significantly limited by pasture between subpopulations. Inbreeding was not detected within any subpopulation.The main findings of this thesis were that evidence of species decline was inconclusive, with possible species expansion and undetected subpopulations. Dispersal was limited by dispersal distance but not by pasture and no subpopulation was subject to significant inbreeding. Current research indicates that pasture does not negatively affect the species, and may be beneficial in the formation and maintenance of habitat.