Tuesday, April 7, 2020

[Herpetology • 2020] Riolama grandis & R. stellata • Lizards from the Lost World: Two New Species and Evolutionary Relationships of the Pantepui Highland Riolama (Gymnophthalmidae)


Riolama stellata & R. grandis
Recoder, Prates, Marques-Souza, Camacho, Nunes, Vechio, Ghellere, McDiarmid & Rodrigues, 2020


Abstract
The Pantepui region of northern South America harbours an endemic fauna that differs dramatically from those of the surrounding lowland rainforests and savannas. A component of this unique fauna is Riolama, a poorly known genus of microteiid lizards with four described and two undescribed species restricted to tepui mountains. We here implement an integrative approach to formally describe the two unnamed species and investigate the phylogenetic relationships and timing of diversification in Riolama using a fossil-calibrated molecular approach. Our results suggest that diversification initiated in Riolama during the Oligocene (c. 28 Mya), thereby characterizing the genus as an ancient lineage. This supports the Plateau biogeographic hypothesis to explain the diversification of the Pantepui fauna. Our divergence time estimation analysis also provides an updated temporal framework for the diversification of the highly diverse Gymnophthalmidae clade.

Keywords: diversity, endemism, herpetofauna, MRCA, taxonomy, tepui




 Riolama grandis in life.
 paratype (MZUSP 116629, field number MTR 40266), a juvenile male with 41.0 mm SVL.

Riolama grandis Recoder et al., sp. nov.
Riolama sp. nov. a, McDiarmid et al., 1988: 669. 
Riolama sp. A (Neblina), McDiarmid & Donnelly, 2005: 515, 540; Kok, 2015: 501, fig. 7.
"The Brown Giant"

Etymology: The specific epithet, grandis, is a Latin adjective, meaning ‘big’ or ‘large’, in reference to the larger body size of this new species compared to congeners



Paratopotype of Riolama stellata in life (MZUSP 116617, field number MTR 40309), an adult male with 41.9 mm SVL.  

Riolama stellata Recoder et al., sp. nov.
Riolama sp. nov. b, McDiarmid et al., 1988: 669. 
Riolama sp. B (Neblina), McDiarmid & Donnelly, 2005: 515, 540; Kok, 2015: 501, fig. 7.
"The Night Sky" 

Etymology: The specific epithet is the Latin adjective stellatus, which means ‘starred’, referring to the ventral and lateral colour pattern composed of light dots scattered on a dark background, which resemble a starry night sky.


 Renato Recoder, Ivan Prates, Sergio Marques-Souza, Agustín Camacho, Pedro M. Sales Nunes, Francisco Dal Vechio, José Mario Ghellere, Roy W. McDiarmid and Miguel Trefaut Rodrigues. 2020. Lizards from the Lost World: Two New Species and Evolutionary Relationships of the Pantepui Highland Riolama (Gymnophthalmidae). Zoological Journal of the Linnean Society. zlz168. DOI:  10.1093/zoolinnean/zlz168 

Lagartos da Neblina: cientistas descrevem novas espécies do ponto mais alto do Brasil 
Novos lagartos do pico da Neblina


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