More than two million species have been described so far, but our knowledge on most taxa remains scarce or inexistent, and the available biodiversity data is often taxonomically, phylogenetically and spatially biased. Unevenness in research effort across species or regions can interact with data biases and compromise our ability to properly study and conserve biodiversity. Herein, we assess the influence of biological, conservation, geographic and socioeconomic correlates of reptile research effort globally and across six biogeographic realms. We combine bibliometric data from the Scopus database with trait-based approaches and provide research effort information for 10 531 reptile species, modelling it as a function of 10 putative correlates of species-level variation in research effort through negative binomial generalised mixed effect models. We show that reptile research effort is highly skewed toward certain taxa and regions, such as turtles, crocodiles, tuatara, viperids, pythons and some anguimorph lizards, as well as for temperate compared to tropical regions. Our findings indicate that greater research attention is directed towards large-sized and early described reptile species, particularly those whose geographic range overlap with biodiversity institutions. Although we demonstrate that biological and socioeconomic factors more strongly affect reptile research effort variation, geography and conservation-related factors also matter. Global patterns are mostly consistent, but variation across realms were observed and likely reflects differences in socioeconomic attributes as well as in the amount of species to be studied in each realm. Directing researchers and citizen scientists' attention toward understudied taxa will contribute to alleviate this biased biodiversity knowledge, although the sheer amount of species in tropical regions inevitably makes it a long-term solution. Performing comparative studies across species with similar levels of research attention could represent a more immediate and feasible alternative.

Exotic species are major threats to biodiversity worldwide. Domestic dogs (Canis familiaris) are among the most common invasive predators in the world, interacting with wildlife in many ways. We present ecological data based on camera traps and occasional observations of free–roaming domestic dogs from localities within the Brazilian Atlantic forest and Cerrado hotspots. Canis familiaris was the second most abundant mammal species, and the most abundant carnivore. Dogs chased, killed, and/or competed with at least 26 native species. They consumed none of the killed animals, which together with the predominant records of solitary individuals acting during the daytime indicates they are mainly free–roaming dogs relying on humans for food and shelter. The high numbers of dogs and the wide range of prey suggest wildlife could be greatly impacted by domestic dogs, especially in areas that are highly threatened by anthropogenic activities, such as biodiversity hotspots. We highlight possible measures (such as the eradication or removal of dogs from natural areas) that could help to reduce the environmental damage caused by domestic dogs in the region.

Most species remain unknown to science and might go extinct before we recognize their existence. Although specimens belonging to many of these unknown taxa may already be housed in scientific collections, they can remain ‘shelved’ for years bearing the wrong name or without a formal name. We investigate factors underlying variation in time lag between collection and description dates for 2356 reptile species described worldwide between 1992 and 2017. We modelled the time to description using biological and sociological variables in a time-to-event analysis. Time lag between collection and description varied from zero to 155 years (median = 5). More than one-quarter of species involved specimens ‘shelved’ for 12 years or more. The time lag was shorter when the collector of the holotype – specimen serving as the name-bearer of the species – was an author of the description, while taxonomic revisions uncovered species with longer time lags. Unknown species collected by non-taxonomists and ‘shelved’ in scientific collections remained incorrectly identified for a much longer time. Taxonomic revisions are crucial to reverse this trend and improve benefits of the collecting performed by non-taxonomists. Our findings reveal the kinds of preserved reptile specimens that most likely represent unknown species in scientific collections.

Brodie et al., 1991). Although antipredator mechanisms are known for several different animal groups (Edmunds, 1974), behavioral observations in nature might prove difficult. Most species are naturally rare (Preston, 1948), and in situ observations of predator-prey interactions are generally scarce (Fitch, 1987). However, for many species this difficulty can be overcome through the inspection of specimens housed in scientific collections. For instance, individuals

We present information on the reproduction of Gymnodactylus darwinii based on macroscopic analysis of its gonads. We found no sexual dimorphism in body size (SVL) between adult males and females, but males had, on average, wider heads and longer forearms. Both sexes had very similar sizes at sexual maturity and maximum body sizes, suggesting male–male competition for resources does not occur, and/or there are no sexual differences in survival rates. The smallest specimen had 24 mm SVL, and juvenile/immature specimens of similar or slightly bigger sizes were collected throughout the year suggesting a continuous turnover of individuals in the population. Adult males showed a continuous reproductive cycle, contrasting with a seasonal cycle of females, where maximum gonadal volume was observed from September to December. This is not uncommon and may be related to differential response to local environmental conditions, or because distinct investment in reproduction. Females have a small and fixed clutch size (two eggs per clutch), a pattern also observed in its congener G. amarali and in many geckonids, which is likely due to phylogenetic inertia. To compensate for a fixed clutch size, females may be able to lay more than one clutch per reproductive season.