Characteristics of Mountain Lion Bed, Cache and Kill Sites In Northeastern Oregon

We described mountain lion (Puma concolor) habitat characteristics during two studies in the same area of northeastern Oregon during the 1990s. In the first study (1992-1994) we evaluated micro-habitat features associated with 61 diurnal bed sites that were not associated with kills. We used similar techniques in the second study (1996- 1998) to evaluate habitat features at 79 cache sites near lion-killed prey. A dog was used to find 93% of the diurnal bed sites. Radio telemetry triangulation was used in the second study. Characteristics of diurnal bed sites and cache sites were compared with random habitat plots. Rock structure and downed logs were identified as important habitat components at diurnal bed sites. Canopy cover at cache sites was significantly higher than at random sites. Cache sites also were associated with rock structure, but not to the same degree as diurnal bed sites. In both studies mountain lions used sites in close proximity to habitat edges more frequently than expected based on random plots. Understanding the similarities and differences of habitat use at diurnal bed, cache and kill sites sheds light on the ecological adaptation of mountain lions to the multiple environmental influences and disturbances of managed forests

The braincase and inner ear of ‘Metriorhynchus’ cf. ‘M.’ brachyrhynchus – implications for aquatic sensory adaptations in crocodylomorphs

During their long evolutionary history crocodylomorphs achieved a great diversity of body sizes, ecomorphotypes and inferred feeding ecologies. One unique group of crocodylomorphs are the thalattosuchians, which lived during the Jurassic and Cretaceous (ca. 191–125 Ma). They transitioned from shallow marine species, like teleosauroids, into fully pelagic forms with paddle shaped limbs and a vertically orientated tail fluke, the metriorhynchids. The osteological adaptations that allowed metriorhynchids to live in the water are generally well understood, but less is known about their neurosensory and endocranial systems, such as the brain, inner ears, sinuses and cranial nerves and how they relate to their aquatic lifestyle. Based on micro-computed tomography (μCT) data and three-dimensional models, we here describe the braincase and endocranial anatomy of a fully marine metriorhynchid, ‘Metriorhynchus’ cf. ‘M.’ brachyrhynchus (NHMUK PV OR 32617). We found several neuroanatomical features that likely helped this species function in its marine environment. These include a unique flexure in the brain endocast not seen in other thalattosuchians. Other features that have previously been seen in thalattosuchians include enlarged cerebral hemispheres, a hypertrophied venous sinus system, enlarged internal carotid arteries and foramina, and closed/absent lateral pharyngotympanic foramina. The specimen also possesses a pelagic metriorhynchid bony labyrinth morphology, with a compact and dorsoventrally short shape, thick semicircular canals, an enlarged vestibule and potentially a short cochlear duct. A review of character distribution confirms that some of these features evolved at the base of Thalattosuchia in semiaquatic species, long before metriorhynchids became pelagic, suggesting that endocranial anatomy helped allow metriorhynchoids colonize the ocean realm.Fil: Schwab, Julia A.. University of Edinburgh; Reino UnidoFil: Young, Mark T.. University of Edinburgh; Reino UnidoFil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Witmer, Lawrence. Ohio University; Estados UnidosFil: Walsh, Stig A.. University of Southampton; Reino UnidoFil: Katsamensis, Orestis. Faculty Of Engineering And Physical Sciences; Reino UnidoFil: Brusatte, Stephen L.. University of Edinburgh; Reino Unid

Ontogenetic variation in the crocodylian vestibular system

Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known about the vestibular system of the inner ear. Here we use 30 high-resolution computed tomography (CT) scans and three-dimensional geometric morphometrics to investigate the size and shape changes of crocodylian endosseous labyrinths throughout ontogeny, across four stages (hatchling, juvenile, subadult and adult). We find two major patterns of ontogenetic change. First, the labyrinth increases in size during ontogeny, with negative allometry in relation to skull size. Second, labyrinth shape changes significantly, with hatchlings having shorter semicircular canal radii, with thicker diameters and an overall dorsoventrally shorter labyrinth than those of more mature individuals. We argue that the modification of the labyrinth during crocodylian ontogeny is related to constraints imposed by skull growth, due to fundamental changes in the crocodylian braincase during ontogeny (e.g. verticalisation of the basicranium), rather than changes in locomotion, diet, or other biological functions or behaviours

‘Ear stones’ in crocodylians: a cross-species comparative and ontogenetic survey of otolith structures

The vestibular system of the inner ear is a crucial sensory organ, involved in the sensation of balance and equilibrium. It consists of three semicircular canals that sense angular rotations of the head and the vestibule that detects linear acceleration and gravity. The vestibule often contains structures, known as the otoliths or ‘ear stones’. Otoliths are present in many vertebrates and are particularly well known from the fossil record of fish, but surprisingly have not been described in detail in most tetrapods, living or extinct. Here, we present for the first time a survey of the otoliths of a broad sample of extant crocodylian species, based on computed tomography scans. We find that otoliths are present in numerous crocodylian species of different growth stages, and they continue to increase in size during ontogeny, with positive allometry compared to skull length. Our results confirm that otoliths are a common component of the crocodylian vestibular system, and suggest they play an important role in sensory detection. Otoliths are likely common, but overlooked, constituents of the inner ear in tetrapods, and a broader study of their size, shape and distribution promises insight into sensory abilities

Cephalic salt gland evolution in Mesozoic pelagic crocodylomorphs

Cowgill, Thomas, Young Fls, Mark T, Schwab, Julia A, Walsh, Stig, Witmer, Lawrence M, Herrera, Yanina, Dollman, Kathleen N, Turner, Alan H, Brusatte, Stephen L (2023): Cephalic salt gland evolution in Mesozoic pelagic crocodylomorphs. Zoological Journal of the Linnean Society 197 (3): 812-835, DOI: 10.1093/zoolinnean/zlac027, URL: https://academic.oup.com/zoolinnean/article/197/3/812/659333

Decelerated dinosaur skull evolution with the origin of birds

© 2020 Felice et al. The evolutionary radiation of birds has produced incredible morphological variation, including a huge range of skull form and function. Investigating how this variation arose with respect to non-avian dinosaurs is key to understanding how birds achieved their remarkable success after the Cretaceous–Paleogene extinction event. Using a high-dimensional geometric morphometric approach, we quantified the shape of the skull in unprecedented detail across 354 extant and 37 extinct avian and non-avian dinosaurs. Comparative analyses reveal fundamental differences in how skull shape evolved in birds and non-avian dinosaurs. We find that the overall skull shape evolved faster in non-avian dinosaurs than in birds across all regions of the cranium. In birds, the anterior rostrum is the most rapidly evolving skull region, whereas more posterior regions—such as the parietal, squamosal, and quadrate—exhibited high rates in non-avian dinosaurs. These fast-evolving elements in dinosaurs are strongly associated with feeding biomechanics, forming the jaw joint and supporting the jaw adductor muscles. Rapid pulses of skull evolution coincide with changes to food acquisition strategies and diets, as well as the proliferation of bony skull ornaments. In contrast to the appendicular skeleton, which has been shown to evolve more rapidly in birds, avian cranial morphology is characterised by a striking deceleration in morphological evolution relative to non-avian dinosaurs. These results may be due to the reorganisation of skull structure in birds—including loss of a separate postorbital bone in adults and the emergence of new trade-offs with development and neurosensory demands. Taken together, the remarkable cranial shape diversity in birds was not a product of accelerated evolution from their non-avian relatives, despite their frequent portrayal as an icon of adaptive radiations

The water-land-food-energy-climate nexus for a resource efficient Europe.

Α novel methodology for addressing policy inconsistencies and knowledge gaps that hinder the transition to a greater resource efficiency Europe is proposed. We focus on the integration of all different sectors that interact and influence each other, namely the “water- energy- food- land use- climate nexus” and we develop tools for identifying and quantifying their complex interlinkages under the influence of climate change. In order to achieve this, we employ a series of sophisticated models (referred to as “thematic models”), each of which addresses a different nexus dimension, or a combination of a few, while none addresses all nexus dimensions in an integrative manner. We use dynamic systems modeling and other complexity science techniques in order to “merge” different thematic model outputs in a single coherent result, which is presented to the user in an easyto-comprehend Serious Game environment. This way, the effect of policies that are designed to affect one field (nexus dimension) on others can be quantified and simulated, thus informing policy-makers for the unintended consequences of their policies, reducing uncertainties, covering knowledge gaps and leading to a resource efficient Europe faste

Ontogeny and phylogeny of ankylosaurs

29 p. : ill., map ; 26 cm.Includes bibliographical references (p. 20-23).Here we report the occurrence of a juvenile ankylosaur from the Upper Cretaceous locality Ukhaa Tolgod in southern Mongolia. The locality is well known for its exquisitely preserved theropods, mammals, and squamates, but until now has not yielded diagnostic ankylosaur material, although ankylosaur specimens are common at the site. The new specimen consists of a nearly complete skull with associated mandible and osteoderms that exhibits the following ankylosaurid synapomorphies: two pairs of osteodermal "horns" projecting from the quadratojugals and squamosals; a wide, triangular skull; a premaxillary beak edge that is not continuous with the maxillary tooth row; and absence of premaxillary teeth. We refer the specimen to Pinacosaurus grangeri based on the presence of a large premaxillary sinus, a quadrate not co-ossified with the paroccipital process, and several pairs of accessory openings in the narial region. The new specimen differs from the holotype and other specimens in having five pairs of openings in the narial region, indicating that extensive morphological variability exists in the narial anatomy of P. grangeri. The specimen is identified as a juvenile based on its small size and the incomplete fusion of secondary dermal ossifications to the skull roof, exposing sutural boundaries. Juvenile ankylosaur skulls are rare, but crucial for understanding the basic anatomy of the highly fused and apomorphic adult skull. Morphological data from the new skull and other specimens are added to existing phylogenetic analyses of the Ankylosauria in order to identify diagnostic characters that aid in resolving ankylosaur relationships. The specimen also provides data on the ontogenetic sequence of secondary dermal ossification. Presence of dermal ossifications covering only the narial region, quadratojugals, and squamosals supports the hypothesis that osteoderms in these areas appear early in ontogeny. Furthermore, two well-developed osteoderms were found in close apposition but unfused tothe ventrolateral edges of the mandible. All known mandibles from adult ankylosaurs exhibit fusion of these elements to the underlying bones. Thus, mandibular osteoderms also appear relatively early but do not become fused until much later

‘Ear stones’ in crocodylians: a cross-species comparative and ontogenetic survey of otolith structures

The vestibular system of the inner ear is a crucial sensory organ, involved in the sensation of balance and equilibrium. It consists of three semicircular canals that sense angular rotations of the head and the vestibule that detects linear acceleration and gravity. The vestibule often contains structures, known as the otoliths or ‘ear stones’. Otoliths are present in many vertebrates and are particularly well known from the fossil record of fish, but surprisingly have not been described in detail in most tetrapods, living or extinct. Here, we present for the first time a survey of the otoliths of a broad sample of extant crocodylian species, based on computed tomography scans. We find that otoliths are present in numerous crocodylian species of different growth stages, and they continue to increase in size during ontogeny, with positive allometry compared to skull length. Our results confirm that otoliths are a common component of the crocodylian vestibular system, and suggest they play an important role in sensory detection. Otoliths are likely common, but overlooked, constituents of the inner ear in tetrapods, and a broader study of their size, shape and distribution promises insight into sensory abilities.Facultad de Ciencias Naturales y Muse

Variation, variability, and the origin of the avian endocranium:Insights from the anatomy of alioramus altai (theropoda: Tyrannosauroidea)

The internal braincase anatomy of the holotype of Alioramus altai, a relatively small-bodied tyrannosauroid from the Late Cretaceous of Mongolia, was studied using high-resolution computed tomography. A number of derived characters strengthen the diagnosis of this taxon as both a tyrannosauroid and a unique, new species (e.g., endocranial position of the gasserian ganglion, internal ramification of the facial nerve). Also present are features intermediate between the basal theropod and avialan conditions that optimize as the ancestral condition for Coelurosauria--a diverse group of derived theropods that includes modern birds. The expression of several primitive theropod features as derived character states within Tyrannosauroidea establishes previously unrecognized evolutionary complexity and morphological plasticity at the base of Coelurosauria. It also demonstrates the critical role heterochrony may have played in driving patterns of endocranial variability within the group and potentially reveals stages in the evolution of neuroanatomical development that could not be inferred based solely on developmental observations of the major archosaurian crown clades. We discuss the integration of paleontology with variability studies, especially as applied to the nature of morphological transformations along the phylogenetically long branches that tend to separate the crown clades of major vertebrate groups