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11 result(s) for "Apterygidae"
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Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx
Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs. We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates. The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.
Kiwi translocation review: Are we releasing enough birds and to the right places?
Translocations of kiwi (Apteryx spp.) are one of the most common and growing types of conservation translocations in New Zealand. However, their outcomes remain mostly unpublished, which does not allow for sharing of lessons learnt from past developments. We reviewed 102 kiwi translocations from the 19th century until 2018, and identified factors affecting their outcome. North Island brown kiwi (A. mantelli) was the most translocated species, but the highest impact of translocations on the improvement of conservation status was for the rarest taxa: little spotted kiwi (A. owenii), rowi (A. rowi), and Haast tokoeka (A. australis 'Haast'). Translocations are typically used for creating secure populations and, more recently, for ecosystem restoration objectives and meta-population management. We developed a set of criteria to evaluate the outcome of introductions and reintroductions based on demographic parameters alongside current recommendations on genetic make-up of translocated populations. These criteria allowed us to categorise historical and recent translocations that were carried out for a wide array of objectives. Currently, based on these criteria, only a few translocated populations can be considered successful in the medium–long term: 15+ years following the release of a genetically diverse population (40+ unrelated individuals). Most historical translocations failed or require further genetic and habitat management. However, a majority of kiwi translocations have occurred over the last two decades and, while several populations have successfully established, for most of them, it is too soon to assess their medium-long term outcome. An analysis of factors affecting translocation outcomes revealed that, despite ongoing predator control, populations at small, unfenced sites on the mainland suffer from dispersal and predation, which has negative demographic and genetic consequences. Releases to larger mainland sites and predator-free areas have increased survival times, which indicates higher chances for a positive translocation outcome. Moreover, translocated wild-caught and captive-sourced birds survived longer compared to birds from the Operation Nest Egg programme, particularly at sites that were not predator-free. We highlight the need for genetic considerations in the planning and adaptive management of proposed and existing translocated populations. Specifically, we suggest that differences in kiwi survival, based on the type of released birds and release site's area size and predator status, should be considered during translocation planning. Similarly, we encourage a standardised monitoring approach, increased reporting, and publishing the outcomes of translocations.
Identification of the type locality of the South Island Brown Kiwi Apteryx australis
New Zealand’s iconic, flightless and endangered species of kiwi (Apterygidae) are at risk of extinction on the mainland due to predation by introduced mammals. In order to provide effective conservation management a robust understanding of genetic variation in the group is needed. Recent genomic analyses of kiwi suggest that several cryptic and as yet undescribed lineages occur in the South Island, most notably within a taxon that has until now been called Apteryx australis australis, the South Island Brown Kiwi or Tokoeka. In order for these lineages to be formally described and treated as separate conservation units it is first necessary to determine from which lineage of Tokoeka the holotype was collected. To determine this, we generated a near complete mitochondrial genome and nuclear SNP dataset for the holotype and compared these with living kiwi populations. Our results definitively assign the holotype to the Stewart Island population of brown kiwi which until now was recognized as a distinct subspecies Apteryx australis lawyri (Rothschild, 1893). This leads us to synonymize Apteryx lawryi Rothschild, 1893 within Apteryx australis Shaw, 1813. As the holotype was collected by sealers in the early 19th century, the result also provides a novel insight into the activities of early sealers in New Zealand. New names for taxa will need to be erected for any mainland South Island taxa described, because there are no scientific names available for taxonomy.
The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds
Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These 'bill-tip organs' allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill-tip organs and associated somatosensory brain regions are likely a result of similar ecological selective pressures, with inter-specific variations reflecting finer-scale niche differentiation.
Redescription of the kiwi tick Ixodes anatis (Acari: Ixodidae) from New Zealand, with notes on its biology
Ixodes anatis Chilton is of veterinary and conservation importance in New Zealand due to its association with the threatened kiwi (Aves: Apterygidae: Apteryx spp.). Since the tick’s description in 1904, there has been debate regarding its correct taxonomic position and nomenclature. Herein all life stages of this species are redescribed and accompanied by electron micrographs and drawings. The systematics, host preferences, distribution, disease relationships and conservation biology of the species are also discussed.
More than One Way of Being a Moa: Differences in Leg Bone Robustness Map Divergent Evolutionary Trajectories in Dinornithidae and Emeidae (Dinornithiformes)
The extinct moa of New Zealand included three families (Megalapterygidae; Dinornithidae; Emeidae) of flightless palaeognath bird, ranging in mass from <15 kg to >200 kg. They are perceived to have evolved extremely robust leg bones, yet current estimates of body mass have very wide confidence intervals. Without reliable estimators of mass, the extent to which dinornithid and emeid hindlimbs were more robust than modern species remains unclear. Using the convex hull volumetric-based method on CT-scanned skeletons, we estimate the mass of a female Dinornis robustus (Dinornithidae) at 196 kg (range 155-245 kg) and of a female Pachyornis australis (Emeidae) as 50 kg (range 33-68 kg). Finite element analysis of CT-scanned femora and tibiotarsi of two moa and six species of modern palaeognath showed that P. australis experienced the lowest values for stress under all loading conditions, confirming it to be highly robust. In contrast, stress values in the femur of D. robustus were similar to those of modern flightless birds, whereas the tibiotarsus experienced the highest level of stress of any palaeognath. We consider that these two families of Dinornithiformes diverged in their biomechanical responses to selection for robustness and mobility, and exaggerated hindlimb strength was not the only successful evolutionary pathway.
Kiwi forego vision in the guidance of their nocturnal activities
Background: In vision, there is a trade-off between sensitivity and resolution, and any eye which maximises information gain at low light levels needs to be large. This imposes exacting constraints upon vision in nocturnal flying birds. Eyes are essentially heavy, fluid-filled chambers, and in flying birds their increased size is countered by selection for both reduced body mass and the distribution of mass towards the body core. Freed from these mass constraints, it would be predicted that in flightless birds nocturnality should favour the evolution of large eyes and reliance upon visual cues for the guidance of activity. Methodology/Principal Findings: We show that in Kiwi (Apterygidae), flightlessness and nocturnality have, in fact, resulted in the opposite outcome. Kiwi show minimal reliance upon vision indicated by eye structure, visual field topography, and brain structures, and increased reliance upon tactile and olfactory information. Conclusions/Significance: This lack of reliance upon vision and increased reliance upon tactile and olfactory information in Kiwi is markedly similar to the situation in nocturnal mammals that exploit the forest floor. That Kiwi and mammals evolved to exploit these habitats quite independently provides evidence for convergent evolution in their sensory capacities that are tuned to a common set of perceptual challenges found in forest floor habitats at night and which cannot be met by the vertebrate visual system. We propose that the Kiwi visual system has undergone adaptive regressive evolution driven by the trade-off between the relatively low rate of gain of visual information that is possible at low light levels, and the metabolic costs of extracting that information.
Evidence for an Auditory Fovea in the New Zealand Kiwi (Apteryx mantelli)
Exploits known correlations between morphology and physiology in the avian inner ear and brainstem to predict the frequency range of best hearing in the North Island brown kiwi. Looks at how such evidence may be an adaptation to a nocturnal lifestyle in which auditory communication plays a dominant role. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
Bill Morphology of Ibises Suggests a Remote-Tactile Sensory System for Prey Detection
Birds that forage by probing must often use senses other than vision to find their prey. Remote touch is a sense based on the interception of vibrations produced by moving prey in the substrate or on the evaluation of pressure patterns produced by hard-shelled sessile prey. In probing birds, this system is mediated by an organ made up of clusters of mechanoreceptors housed within pits in the bone of the bill-tips. This bill-tip organ was first described in probing shorebirds (Scolopacidae), and more recently in kiwi (Apterygidae). Here, we describe this bill-tip organ in a third family of probing birds, the ibises (Threskiornithidae). We examined the bill morphology of 11 species of ibis from 8 genera. We found bill-tip organs in species in a wide range of habitat types, from predominantly terrestrial to predominantly aquatic, which suggests that ibises may use remote touch when foraging both in water and in granular substrates. Our data imply a link between bill-tip morphology and habitat use—a pattern that we believe warrants further investigation.
Remote touch prey-detection by Madagascar crested ibises Lophotibis cristata urschi
Birds that forage by probing must often rely on sensory systems other than vision to detect their buried prey. Such senses may include hearing (e.g. Australian magpies (Atramidae), American robins (Turdidae)) or chemical senses/olfaction (e.g. kiwi (Apterygidae) and some shorebirds (Scolopacidae)). Probe foraging kiwi and shorebirds are also able to use vibrotactile cues to locate prey buried in the substrate at some distance from their bill-tips ('remote touch'). These birds possess an organ consisting of a honey-comb of sensory pits in bone of the bill-tips, packed with mechanoreceptive nerve ending (Herbst corpuscles). Such a bill-tip organ has recently also been described in ibises (Threskiornithinae), but its function not elucidated. We designed a foraging experiment presenting mealworm prey to three captive Madagascar crested ibises Lophotibis cristata urschi under a variety of trial conditions to discover whether they were using remote touch, mediated by their bill-tip organ; chemosense/olfaction; or hearing to locate buried prey. The ibises were reliant on remote touch for prey detection - the first time this sensory system has been demonstrated for this group of birds. They did not appear to use hearing or chemical senses/olfaction to aid in prey detection.