4 research outputs found
Quantitative analysis of morphometric data of pre-modern birds: phylogenetic versus ecological signal
Birds are one of the most diverse clades of extant terrestrial vertebrates, a diversity that first
arose during the Mesozoic as a multitude of lineages of pre-neornithine (stem) birds
appeared but did not survive into the Cenozoic Era. Modern birds (Neornithes) inhabit an
extensive array of ecologically distinct habitats and have specific and varied foraging
strategies. Likewise, the morphological disparity among Mesozoic lineages appears to
underscore a significant degree of ecological diversity, yet attempts to determine lineage specific ecologies have mainly been limited to superficial narratives. In recent years,
numerous studies have used various morphometric proxies to interpret the
paleoecology of Mesozoic bird lineages, but largely without evaluating the interplay
between ecological and phylogenetic signals. Moreover, most studies of this sort
transform the original data into logarithms to control dimensionality, underestimating
the biases induced upon such transformations. The goal of this study is to
quantitatively address the ecomorphology of crown-group Neornithes using a dense
sample of raw forelimb and hindlimb measurements, and to examine if such results can be
used to infer the ecologies of Mesozoic bird lineages. To that end, scaling of limb
measurements and ecological data from modern birds was assessed statistically using
phylogenetic comparative methods, followed by the inclusion of fossil taxa. A strong
relationship was recovered between humerus and hindlimb allometric scaling and
phylogeny. Our results indicate that while some ecological classes of modern birds
can be discriminated from each other, phylogenetic signature can overwhelm
ecological signal in morphometric data, potentially limiting the inferences that can be
made from ecomorphological studies. Furthermore, we found differential scaling of leg
bones among Early Cretaceous enantiornithines and ornithuromorphs, a result hinting that
habitat partitioning among different lineages could be a pervasive phenomenon in avian
evolutio
A theropod trackway providing evidence of a pathological foot from the exceptional locality of Las Hoyas (upper Barremian, Serrania de Cuenca, Spain)
We describe a trackway (LH-Mg-10-16) occurring in laminated carbonated limestones of the
Las Hoyas locality, Serranı´a de Cuenca, Spain. It is unmistakably a large theropod dinosaur
trackway encompassing two unusual aspects, namely, wide-steps, and a set of equally
deformed left footprints (with a dislocated digit). The layer also preserves other vertebrate
trails (fish Undichna) and different impressions in the sediment. To address these complex
settings, we devised a multidisciplinary approach, including the ichnological and taphonomical descriptions, characterisation of the rock lithofacies using thin-sections, 3D structuredlight digitalisation with a high precision of 200–400 μm, and a geometric morphometric comparison with a large sample of bipedal dinosaur trackways. Sedimentary analyses showed
that the trackway was produced in a humid, benthonic microbial mat, the consistency and
plasticity of which enabled the preservation of the details of the movement of the animal.
The results of the geometric analysis indicate that the “wide-steps” of the trackway is not
unusual compared to other trackways, providing evidence that it was made by a single individual with an estimated hip height approximately 2 m. Analogous pathologies in extant
archosaurs that yield the combination of wide steps and deformed digits in the same trackway were considered. All results mutually support the hypothesis that a large theropod dinosaur, with a pathological foot, generated the trackway as it crossed an area of shallow water
while slowly walking towards the main water source, thus stepping steadily over the benthonic mat over which multiple fish were swimmin
A theropod trackway providing evidence of a pathological foot from the exceptional locality of Las Hoyas (upper Barremian, Serranía de Cuenca, Spain)
We describe a trackway (LH-Mg-10-16) occurring in laminated carbonated limestones of the Las Hoyas locality, Serranía de Cuenca, Spain. It is unmistakably a large theropod dinosaur trackway encompassing two unusual aspects, namely, wide-steps, and a set of equally deformed left footprints (with a dislocated digit). The layer also preserves other vertebrate trails (fish Undichna) and different impressions in the sediment. To address these complex settings, we devised a multidisciplinary approach, including the ichnological and taphonomical descriptions, characterisation of the rock lithofacies using thin-sections, 3D structured-light digitalisation with a high precision of 200-400 μm, and a geometric morphometric comparison with a large sample of bipedal dinosaur trackways. Sedimentary analyses showed that the trackway was produced in a humid, benthonic microbial mat, the consistency and plasticity of which enabled the preservation of the details of the movement of the animal. The results of the geometric analysis indicate that the 'wide-steps' of the trackway is not unusual compared to other trackways, providing evidence that it was made by a single individual with an estimated hip height approximately 2 m. Analogous pathologies in extant archosaurs that yield the combination of wide steps and deformed digits in the same trackway were considered. All results mutually support the hypothesis that a large theropod dinosaur, with a pathological foot, generated the trackway as it crossed an area of shallow water while slowly walking towards the main water source, thus stepping steadily over the benthonic mat over which multiple fish were swimming
Table S1 from Open data and digital morphology
Summary of main online repositories for 3D digital morphological data