The Biggest Megaraptoridae (Theropoda: Coelurosauria) of South America

Megaraptorans are a theropod clade distributed in former Gondwana landmasses and Asia. Most members of the clade are known from early Cretaceous to Turonian times whereas Maastrichtian megaraptorans are known just from isolated and poorly informative remains. The aim of present contribution is to describe a partial skeleton of a megaraptorid coming from Maastrichtian beds at Santa Cruz province, Argentina. This new taxon constitutes the most informative megaraptoran from post-Turonian beds. Phylogenetic analysis nested the new taxon together with South American megaraptorans in a monophyletic clade, whereas Australian and Asian members constitute successive stem groups. South American forms differ from more basal megaraptorans in several anatomical features and in being much larger and more robustly built. It is possible that the Cenomanian-Turonian extinction of carcharodontosaurids was allowed to megaraptorans to occupy the niche of top predators in South America.

The Contribution of Kurī (Polynesian Dog) to the Ecological Impacts of the Human Settlement of Aotearoa New Zealand

The pre-human Aotearoa New Zealand fauna was dominated by avian and reptilian species. Prior to first human settlement by East Polynesian colonists, the top predators were two giant raptorial birds. Aside from humans themselves, colonisation also resulted in the simultaneous introduction of two novel mammalian predators into this naive ecosystem, the kiore (Pacific rat) and kurī (Polynesian dog). While the ecological impacts of kiore are relatively well understood, those of kurī are difficult to assess, and as such kurī have frequently been disregarded as having any meaningful impact on New Zealand’s biodiversity. Here we use the archaeological and palaeoecological record to reassess the potential impacts of kurī on this ecosystem. We argue that far from being confined to villages, kurī could have had a significant widespread but relatively localised impact on New Zealand’s avian, reptilian and marine mammal (seals and sea lions) fauna as a novel predator of medium-sized species. In this way, kurī potentially amplified the already significant impacts of Polynesian colonists and their descendants on New Zealand’s ecosystem, prior to European arrival. As such, kurī should be included in models of human impact in addition to over-hunting, environmental modification and predation by kiore.

Assessing bird predation on New Zealand’s lizard fauna using lizard-mimicking replicas

<p>Wildlife management is fraught with challenges due to the complexities of community ecology. Interventions aimed at restoring ecosystems, or managing species, can have unintended negative outcomes for target species. The effect of avian predation on native lizard fauna in New Zealand is not clearly understood, despite birds being regarded as top predators within mammal-free ecosystems. At least thirty-one species of bird have been recorded preying on native lizards, but few studies have directly addressed avian predation on lizards, with the majority of evidence sourced from published anecdotes. New Zealand’s herpetofauna are already vulnerable due to range contractions resulting from mammalian predation and habitat loss, with 87% of New Zealand lizard species considered ‘At Risk’ or ‘Threatened’. Understanding the risks posed to lizards will help to inform successful management of vulnerable populations. I used lizard-mimicking replicas to identify and assess predation rates exerted by bird species on lizard populations within the Wellington region of New Zealand. I examined the use of lizard replicas as a tool to quantify predation by examining how birds interacted with replicas and comparing attack rates with novel items simultaneously placed in the field. I determined which bird species were preying on replicas, the extent of such predation, and whether site vegetation or daily weather influenced the probability of avian attack on replicas. Although attack frequency did not differ between novel items and lizard replicas, birds exhibited a realistic predatory response by preferentially attacking the head of lizard replicas. Interactions by birds with lizard-mimicking replicas cannot be confirmed as true predation attempts, but lizard replicas can nevertheless be used to quantify predation pressures exerted on lizard populations by opportunistic bird species. Seven ground-foraging bird species were found to attack lizard replicas. Two species, the pūkeko (Porphyrio melanotus melanotus) and southern black-backed gull (Larus dominicanus dominicanus), were identified as high impact species. The average predation risk experienced by lizard replicas varied greatly across environments, with 0 – 25% of replicas attacked daily at sites. Canopy cover and daily rainfall were not significant predictors, but potentially decreased the likelihood of replica attack. Predation risk varied for lizard replicas as a result of differing assemblages of bird predators at sites, and the presence and foraging behaviour of specific predatory birds. Predation by birds is likely to be an issue where predation pressure is high, or lizard populations are small, range restricted, or recovering from the presence of mammalian predators. When managing vulnerable lizard populations, managers should take into account the threats posed by avian predators so that lizard communities can recover successfully following the same trajectory as native birds.</p>

Assessing bird predation on New Zealand’s lizard fauna using lizard-mimicking replicas

<p>Wildlife management is fraught with challenges due to the complexities of community ecology. Interventions aimed at restoring ecosystems, or managing species, can have unintended negative outcomes for target species. The effect of avian predation on native lizard fauna in New Zealand is not clearly understood, despite birds being regarded as top predators within mammal-free ecosystems. At least thirty-one species of bird have been recorded preying on native lizards, but few studies have directly addressed avian predation on lizards, with the majority of evidence sourced from published anecdotes. New Zealand’s herpetofauna are already vulnerable due to range contractions resulting from mammalian predation and habitat loss, with 87% of New Zealand lizard species considered ‘At Risk’ or ‘Threatened’. Understanding the risks posed to lizards will help to inform successful management of vulnerable populations. I used lizard-mimicking replicas to identify and assess predation rates exerted by bird species on lizard populations within the Wellington region of New Zealand. I examined the use of lizard replicas as a tool to quantify predation by examining how birds interacted with replicas and comparing attack rates with novel items simultaneously placed in the field. I determined which bird species were preying on replicas, the extent of such predation, and whether site vegetation or daily weather influenced the probability of avian attack on replicas. Although attack frequency did not differ between novel items and lizard replicas, birds exhibited a realistic predatory response by preferentially attacking the head of lizard replicas. Interactions by birds with lizard-mimicking replicas cannot be confirmed as true predation attempts, but lizard replicas can nevertheless be used to quantify predation pressures exerted on lizard populations by opportunistic bird species. Seven ground-foraging bird species were found to attack lizard replicas. Two species, the pūkeko (Porphyrio melanotus melanotus) and southern black-backed gull (Larus dominicanus dominicanus), were identified as high impact species. The average predation risk experienced by lizard replicas varied greatly across environments, with 0 – 25% of replicas attacked daily at sites. Canopy cover and daily rainfall were not significant predictors, but potentially decreased the likelihood of replica attack. Predation risk varied for lizard replicas as a result of differing assemblages of bird predators at sites, and the presence and foraging behaviour of specific predatory birds. Predation by birds is likely to be an issue where predation pressure is high, or lizard populations are small, range restricted, or recovering from the presence of mammalian predators. When managing vulnerable lizard populations, managers should take into account the threats posed by avian predators so that lizard communities can recover successfully following the same trajectory as native birds.</p>

Low-Stress Livestock Handling Protects Cattle in a Five-Predator Habitat

Given the ecological importance of top predators, societies are turning to non-lethal methods for coexistence. Coexistence is challenging when livestock are released within wild predator habitats, even when people supervise or use lethal methods. We report a randomized, controlled design to evaluate low-stress livestock handling (L-SLH), a form of range riding, to deter grizzly (brown) bears, gray wolves, cougars, black bears, and coyotes in Southwestern Alberta. The treatment condition was supervision by two newly hired and trained range riders and an L-SLH practicing range rider. This treatment was compared against a baseline pseudo-control condition of the single experienced range rider working alone. Cattle experienced zero injuries or deaths in either condition. We infer that inexperienced range riders trained and supervised by an experienced rider did not raise or lower the risk to cattle. Also, predators did not shift to the cattle herds protected by fewer range riders. Pending experimental evaluation of other designs, we recommend use of L-SLH.

Where’s the best supermarket deal? Female Southern Rockhopper Penguins (Eudyptes chrysocome) show variable foraging areas during the guard stage at Isla de los Estados, Argentina

Understanding the spatial distribution of seabirds contributes to comprehending their ecological requirements and dispersion patterns. We studied the at-sea distribution of female Southern Rockhopper Penguins (Eudyptes chrysocome (J.R. Forster, 1781)) at Isla de los Estados colony during the early chick-rearing period. We used a clustering analysis approach to identify different groups according to the foraging trip (tracking and diving data from GPS and temperature and depth data loggers) and diet (δ15N composition on blood samples) characteristics. Foraging trips differed in duration, location, and dive depths explored. Females in clusters 1 and 3 traveled longer distances and in opposite directions (36.3 ± 21.3 and 40.3 ± 14.0 km, respectively). Females in cluster 2 fed closer to the colony (16.8 ± 7.8 km). Dives occurred in pelagic habitats. Higher δ15N values suggested a greater proportion of fish (e.g., the Fuegian sprat, Sprattus fuegensis (Jenyns, 1842)) consumption in the northern foraging areas (cluster 1). The variability observed in the spatial distribution suggests flexibility in the foraging behavior of Southern Rockhopper Penguins and availability of adequate foraging areas within the colony range during the early chick-rearing period, both important features for Southern Rockhopper Penguin population. These results contribute to understanding the use of the Southern Ocean by marine mesopredators and top predators and to the marine spatial planning in the area.

Ontogeny, evolution and palaeogeographic distribution of the world’s largest ammonite Parapuzosia (P.) seppenradensis (Landois, 1895)

The world’s largest ammonite, Parapuzosia (P.) seppenradensis (Landois, 1895), fascinated the world ever since the discovery, in 1895, of a specimen of 1.74 metres (m) diameter near Seppenrade in Westfalia, Germany, but subsequent findings of the taxon are exceedingly rare and its systematic position remains enigmatic. Here we revise the historical specimens and document abundant new material from England and Mexico. Our study comprises 154 specimens of large (< 1 m diameter) to giant (> 1m diameter) Parapuzosia from the Santonian and lower Campanian, mostly with stratigraphic information. High-resolution integrated stratigraphy allows for precise cross-Atlantic correlation of the occurrences. Our specimens were analysed regarding morphometry, growth stages and stratigraphic occurrence wherever possible. Our analysis provides insight into the ontogeny of Parapuzosia (P.) seppenradensis and into the evolution of this species from its potential ancestor P. (P.) leptophylla Sharpe, 1857. The latter grew to shell diameters of about 1 m and was restricted to Europe in the early Santonian, but it reached the Gulf of Mexico during the late Santonian. P. (P.) seppenradensis first appears in the uppermost Santonian- earliest Campanian on both sides of the Atlantic. Initially, it also reached diameters of about 1 m, but gradual evolutionary increase in size is seen in the middle early Campanian to diameters of 1.5 to 1.8 m. P. (P.) seppenradensis is characterized by five ontogenetic growth stages and by size dimorphism. We therefore here include the many historic species names used in the past to describe the morphological and size variability of the taxon. The concentration of adult shells in small geographic areas and scarcity of Parapuzosia in nearby coeval outcrop regions may point to a monocyclic, possibly even semelparous reproduction strategy in this giant cephalopod. Its gigantism exceeds a general trend of size increase in late Cretaceous cephalopods. Whether the coeval increase in size of mosasaurs, the top predators in Cretaceous seas, caused ecological pressure on Parapuzosia towards larger diameters remains unclear.