Extinct, obscure or imaginary: the lizard species with the smallest ranges

Meiri, Shai and Bauer, Aaron M. and Allison, Allen and Castro-Herrera, Fernando and Chirio, Laurent and Colli, Guarino and Das, Indraneil and Doan, Tiffany M. and Glaw, Frank and Grismer, Lee L. and Hoogmoed, Marinus and Kraus, Fred and LeBreton, Matthew and Meirte, Danny and Nagy, Zoltán T. and Nogueira, Cristiano de C. and Oliver, Paul and Pauwels, Olivier S. G. and Pincheira-Donoso, Daniel and Shea, Glenn and Sindaco, Roberto and Tallowin, Oliver J. S. and Torres-Carvajal, Omar and Trape, Jean-Francois and Uetz, Peter and Wagner, Philipp and Wang, Yuezhao and Ziegler, Thomas and Roll, Uri and Stevens, George (2018) Extinct, obscure or imaginary: the lizard species with the smallest ranges. Diversity and Distributions, 24 (2). pp. 262-273. ISSN 1472-4642

Full content URL: http://doi.org/10.1111/ddi.12678

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Abstract

Aim

Small geographic ranges make species especially prone to extinction from anthropogenic disturbances or natural stochastic events. We assemble and analyse a comprehensive dataset of all the world's lizard species and identify the species with the smallest ranges—those known only from their type localities. We compare them to wide-ranging species to infer whether specific geographic regions or biological traits predispose species to have small ranges.
Location

Global.
Methods

We extensively surveyed museum collections, the primary literature and our own field records to identify all the species of lizards with a maximum linear geographic extent of <10 km. We compared their biogeography, key biological traits and threat status to those of all other lizards.
Results

One in seven lizards (927 of the 6,568 currently recognized species) are known only from their type localities. These include 213 species known only from a single specimen. Compared to more wide-ranging taxa, they mostly inhabit relatively inaccessible regions at lower, mostly tropical, latitudes. Surprisingly, we found that burrowing lifestyle is a relatively unimportant driver of small range size. Geckos are especially prone to having tiny ranges, and skinks dominate lists of such species not seen for over 50 years, as well as of species known only from their holotype. Two-thirds of these species have no IUCN assessments, and at least 20 are extinct.
Main conclusions

Fourteen per cent of lizard diversity is restricted to a single location, often in inaccessible regions. These species are elusive, usually poorly known and little studied. Many face severe extinction risk, but current knowledge is inadequate to properly assess this for all of them. We recommend that such species become the focus of taxonomic, ecological and survey efforts.

Keywords:Macroecology, accessibility, endemism, extinction, geckos, holotype, range size, skinks, threat, type locality
Subjects:C Biological Sciences > C180 Ecology
Divisions:College of Science > School of Life Sciences
ID Code:30019
Deposited On:15 Dec 2017 15:37

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