A high mountain lizard from Peru: The world’s highest-altitude reptile

Abstract

Life at high altitudes is particularly challenging for ectothermic animals like reptiles and involves the evolution of specialised adaptations to deal with low temperatures, hypoxia and intense UV radiation. As a result, only very few reptile taxa are able to survive above 5,000 m elevation and herpetological observations from these altitudes are exceedingly rare. We report here an exceptional observation of a lizard population (Liolaemus aff. tacnae; Reptilia, Squamata) from the high Andes of Peru. During an ascent of Chachani mountain (6,054 m, 16°11'S, 71°32'W), we observed and documented photographically this species living between 5,000 and 5,400 m above sea level. Following a review of literature, we show that this is the highest known record of a reptile species.

Oxygen environment and metabolic oxygen demand predictably interact to affect thermal behavior in a lizard, Sceloporus occidentalis

“…Whitney, ~4400 m asl) have PO 2 approximating ~12% O 2 at sea level, at which we detected no aerobic effects on thermal behavior. Moreover, most reptiles are found at elevations below 4400‐m asl, with the highest‐elevation species only known to occur up to ~5400 m asl (Cerdeña et al, 2020). At 5400‐m asl PO 2 approximates only ~11% O 2 at sea level, just within the range of hypoxia required to elicit behavioral anapyrexia from S. occidentalis with elevated metabolic rates.…”

“…Whitney, ~4400 m asl) have PO 2 approximating ~12% O 2 at sea level, at which we detected no aerobic effects on thermal behavior. Moreover, most reptiles are found at elevations below 4400-m asl, with the highest-elevation species only known to occur up to ~5400 m asl (Cerdeña et al, 2020).…”

Viviparity imparts a macroevolutionary signature of ecological opportunity in Liolaemus lizards

“…Liolaemus (288 spp), by contrast, is characterized by myriad transitions in parity mode 35,37 . Liolaemus is known for markedly high rates of body size evolution (snout-vent length; SVL) 38 and, as a group, occur in every habitat in South America, from sea level to more than 5,400 meters in elevation, and from tropical to temperate latitudes (from -9.5 to -54°S) 35,39 .…”

“…The geographic distribution of this lineage is truly extraordinary: Liolaemus includes the world's highest-elevation lizard (L. aff. tacnae) 39 , and the southernmost lizard species in the world (L. sarmientoi and L. magellanicus) 40 . As in many other squamate groups, viviparous Liolaemus species inhabit cold environments and the substrate choice of the lineage is fairly well characterized 35,41,42 .…”

Does Hyperoxia Restrict Pyrenean Rock Lizards Iberolacerta bonnali to High Elevations?

“…Mountains cover approximately 30% of the world's land surface [1]. These biodiversity hotspots [2] harbour virtually all life forms (including diversity of bacteria [3,4], insects [5,6], arachnids [7], gastropods [8,9], fish [10,11], amphibians [12,13], mammals [14,15], birds [16], and squamate reptiles [17,18]). Mountain ecological landscapes are characterised by altitudinal zonation [19], where organisms tend to be adapted to a relatively narrow range of environmental conditions including colder temperature regimes (mean and extremes), strong UV irradiance, and lower atmospheric pressure, thus reduced oxygen availability as altitude increases.…”