Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru Part 2: Xenarthra, Carnivora, Perissodactyla, Artiodactyla, and Sirenia

Overlooked jaguar guardians: Indigenous territories and range-wide conservation of a cultural icon

Indigenous territories (ITs) are an integral component of global conservation strategies. We evaluate the range-wide overlap of ITs and the distribution of the jaguar (Panthera onca), a Neotropical apex predator with considerable cultural significance among Indigenous Peoples. We quantified overlap between protected areas (PAs) and ITs among: (1) jaguar range, (2) the species' core habitats, known as Jaguar Conservation Units (JCUs), and (3) corridors connecting JCUs. We further evaluated deforestation rates between 2000 and 2020 among protected, unprotected, and indigenous portions of JCUs and corridors and compared jaguar density estimates among these land tenures. Our results indicate that ITs overlap 27.7% of jaguar range. South American JCUs and corridors, which comprise ~ 94% of jaguar distribution, experienced significantly less deforestation where ITs intersected PAs. We documented an unbalanced ratio of jaguar density estimates between indigenous and non-indigenous areas, highlighting the need for more representative sampling. Collaborative approaches for jaguar conservation, informed and guided by indigenous knowledge, can support more inclusive and effective monitoring that reduces dependence on external support.

Occipital condyle width (OCW) is a highly accurate predictor of body mass in therian mammals

BACKGROUND

Body mass estimation is of paramount importance for paleobiological studies, as body size influences numerous other biological parameters. In mammals, body mass has been traditionally estimated using regression equations based on measurements of the dentition or limb bones, but for many species teeth are unreliable estimators of body mass and postcranial elements are unknown. This issue is exemplified in several groups of extinct mammals that have disproportionately large heads relative to their body size and for which postcranial remains are rare. In these taxa, previous authors have noted that the occiput is unusually small relative to the skull, suggesting that occiput dimensions may be a more accurate predictor of body mass.

RESULTS

The relationship between occipital condyle width (OCW) and body mass was tested using a large dataset (2127 specimens and 404 species) of mammals with associated in vivo body mass. OCW was found to be a strong predictor of body mass across therian mammals, with regression models of Mammalia as a whole producing error values (~ 31.1% error) comparable to within-order regression equations of other skeletal variables in previous studies. Some clades (e.g., monotremes, lagomorphs) exhibited specialized occiput morphology but followed the same allometric relationship as the majority of mammals. Compared to two traditional metrics of body mass estimation, skull length, and head-body length, OCW outperformed both in terms of model accuracy.

CONCLUSIONS

OCW-based regression models provide an alternative method of estimating body mass to traditional craniodental and postcranial metrics and are highly accurate despite the broad taxonomic scope of the dataset. Because OCW accurately predicts body mass in most therian mammals, it can be used to estimate body mass in taxa with no close living analogues without concerns of insufficient phylogenetic bracketing or extrapolating beyond the bounds of the data. This, in turn, provides a robust method for estimating body mass in groups for which body mass estimation has previously been problematic (e.g., "creodonts" and other extinct Paleogene mammals).