Geometric morphometrics is routinely used in ecology and evolution and morphometric datasets are increasingly shared among researchers, allowing for more comprehensive studies and higher statistical power (as a consequence of increased sample size). However, sharing of morphometric data opens up the question of how much nonbiologically relevant variation (i.e., measurement error) is introduced in the resulting datasets and how this variation affects analyses. We perform a set of analyses based on an empirical 3D geometric morphometric dataset. In particular, we quantify the amount of error associated with combining data from multiple devices and digitized by multiple operators and test for the presence of bias. We also extend these analyses to a dataset obtained with a recently developed automated method, which does not require human‐digitized landmarks. Further, we analyze how measurement error affects estimates of phylogenetic signal and how its effect compares with the effect of phylogenetic uncertainty. We show that measurement error can be substantial when combining surface models produced by different devices and even more among landmarks digitized by different operators. We also document the presence of small, but significant, amounts of nonrandom error (i.e., bias). Measurement error is heavily reduced by excluding landmarks that are difficult to digitize. The automated method we tested had low levels of error, if used in combination with a procedure for dimensionality reduction. Estimates of phylogenetic signal can be more affected by measurement error than by phylogenetic uncertainty. Our results generally highlight the importance of landmark choice and the usefulness of estimating measurement error. Further, measurement error may limit comparisons of estimates of phylogenetic signal across studies if these have been performed using different devices or by different operators. Finally, we also show how widely held assumptions do not always hold true, particularly that measurement error affects inference more at a shallower phylogenetic scale and that automated methods perform worse than human digitization.
The establishment of north-west Australia's nineteenth-century pearlshell fisheries led to the first occupation of many arid offshore islands since the early mid-Holocene. The nature of this occupation, and how crews subsisted on such remote landscapes, remains poorly understood. We investigate a rare instance of an archaeobotanical and zooarchaeological record for this colonial-era activity at Bandicoot Bay, Barrow Island. Varied taxonomic representation suggests an atypical subsistence strategy for a maritime industry, involving broad exploitation of resources over several local landscapes and an absence of remains of provisioned food. Identified plant taxa largely conform to resources known ethnographically to have been exploited by north-west Aboriginal communities, and many relate to traditional food practices. The spatial patterning of charred wood and bone suggests multiple burning activities and areas of specific use. Conditions of wood fuel on the island may have prompted the augmentation of fuel, indicated by the presence of non-local wood charcoal and high proportions of calcined bone. These findings (i) are consistent with the hypothesis that the site's occupants originated from the north-west as part of coerced pearling labour and (ii) provide unique insight into the role offshore islands may have occupied in the management of this industry's labour forces. RÉSUMÉAu 19 e siècle, le développement d'une industrie de pêche des huitres perlières dans le nord-ouest de l'Australie entraina la première réoccupation de nombreusesîles arides de cette région, après celles datant du milieu de l'Holocène. La nature de ces occupations et la façon dont leséquipages purent subsister au sein de milieux si isolés demeurent mal comprises. Nous examinons ici un exemple rare d'assemblages archéozoologiques et archéobotaniques pour ce type d'activités de la période coloniale, dans la baie de Bandicoot, Barrow Island. La diversité des représentations taxonomiques de faune suggère une stratégie de subsistance atypique pour une industrie maritime, incluant un mode d'exploitation extensif des ressources issues de plusieurs environnements locaux, ainsi qu'une absence de restes provenant de nourriture approvisionnée. Les taxons botaniques identifiés correspondentà ceux exploités par les communautés aborigènes du nord-ouest du continent, selon les données ethnographiques, et beaucoup sont associés aux pratiques de subsistance traditionnelles. La répartition spatiale des restes anthracologiques et de faune suggère l'existence de plusieurs types de combustion et zones d'activités spécialisées. La disponibilité du bois de feu sur l'île a pu motiver la recherche de solutions pour augmenter les ressources en combustible, comme semble l'indiquer la présence de charbons de bois d'essence non locale et les proportions importantes d'os calcinés. Ces résultats (i) supportent l'hypothèse selon laquelle les occupants de ce siteétaient originaires du nord-ouest du continent et furent déplacés par le biais du système de travail forcé imposé ...
Use of Indigenous divers on nineteenth-century northwest Australian pearling luggers gave rise to a transregional apparatus of coercion, physical mistreatment, and arguably, slavery. Where accounts of conditions experienced by divers are limited to the documents of contemporary colonial men, our contribution explores a rare archaeological perspective. Zooarchaeological and taphonomic analysis of the Bandicoot Bay campsite, Barrow Island, evokes an exploitative labor relationship inherited from a wider colonial process yet actively re-negotiated by its participants through subsistence practices. The operation's pearlers selected a camp that advantaged concerns for labor organization and resource management while their divers seized opportunities for self-directed subsistence.
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