In an article published in the magazine ultrasound A group of Brazilian researchers reports the results of a review of the scientific literature on reptiles published between 1960 and 2021, considering the more than 11,000 species described since the 18th century.
According to the authors, affiliated with the Federal University of Goiás (UFG) and the State University of Campinas (UNICAMP), 15% of the articles published in the period address ten species (four turtles, four snakes, one lizard and one crocodile). . Less than ten articles were published on 90.5% of all species, and none were published on 38.2%.
The reasons why some reptile species are more studied than others, they suggest, have to do with size, habitat type, endangerment, proximity to research institutions, and national income, among other factors that affect research priorities in this field.
“Although there are many more species in tropical regions, there has been much more research on species in temperate regions, especially in the northern hemisphere, where most countries are relatively wealthy and have more research institutions than elsewhere. For For this reason, rich countries should also invest in research on biodiversity in tropical regions,” said Mario R. Moura, one of the three authors.
The other co-authors are Jhonny Guedes, who participated in the study for his doctorate. research sponsored by the UFG Graduate Program in Ecology and Evolution; and José Alexandre Diniz-Filho, his thesis director and professor at the Institute of Biological Sciences (ICB) of the UFG.
Data biases
The authors examined a total of 89,280 articles in the Scopus database, which they say is one of the largest search resources for scientific literature and offers greater journal coverage than many others. They searched for all 11,570 valid reptile species according to the May 2021 publication of the reptile database which collects taxonomic information on all living species of reptiles.
After excluding 1,039 species described after 2015 to allow for potential bias due to recent discovery, they ended up with 10,531 reptile species for which papers had been published between 1960 and 2021. The vast majority (10,157) were scaly (snakes and lizards), but there were also a good number (348) of chelonians (tortoises, galapagos and tortoises).
Unsurprisingly, more papers on species described earlier had been published, due both to the time available for studies and the availability of specimens in the collections of natural history museums. Other biases that caught the attention of the authors included the predominance of large animals among those most studied, a trend also observed with respect to other vertebrates, and the relative abundance of research on species with terrestrial and aquatic habitats, while research on tree species and fossorial species (burrows) were scarcer.
“Generally speaking, the species that are most visible to humans are the most studied. Some lizards that inhabit leaf litter (dead material that has fallen from trees and shrubs to the ground) and many pit snakes have not been studied at all. Collecting at these locations requires more complex methods that can also be expensive,” Moura said.
Thus, the most studied species were the green turtle (Chelonia mydas), with 2,130 articles, and the loggerhead turtle (Caretta caretta), with 2,058. Both lay eggs on beaches around the world each year and are around 1.5m long. The American alligator (Alligator mississippiensis), a 4.5 m or longer crocodilian reptile native to the southeastern United States, ranked sixth among the most studied species, with 1,049 articles published in the period.
The degree to which species are threatened is another key factor influencing the amount of research devoted to them. The turtles just mentioned, for example, are classified as Endangered and Vulnerable, respectively, on the Red List maintained by the International Union for Conservation of Nature (IUCN).
“This is good news. It is important to have as much knowledge as possible about the most threatened species to ensure that conservation strategies are effective,” Moura said.
The authors also detected a research bias toward species whose ranges are close to cities, highways, waterways, and airports, while fewer studies tend to be published on species with ranges in remote or relatively inaccessible areas.
As a long-term solution to the knowledge gap and to counteract these research effort biases, the authors advocate directing the attention of both professional biologists and citizen scientists to understudied taxa. They add that a more immediate and feasible alternative might be to encourage comparative studies of species with similar levels of research attention. Comparisons between species are quite common in herpetology (the study of amphibians and reptiles).
Citation: Reptile Research Is Strongly Influenced by Access to Specimens, Review of Findings (April 5, 2023) Accessed April 5, 2023 from
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