South America’s complex history, along with its diverse topography and climate, has given rise to an exceptionally diverse herpetofauna—as noted by the renowned North American herpetologist William Duellman. Argentina is the country that best summarizes this statement. From the tedious straight roads of the temperate grasslands near the Río de la Plata to the winding curves along the Andes Mountains, Argentine landscapes offer a unique natural mosaic in the Southern Hemisphere. The species composition of reptiles, which are generally habitat specialists, naturally changes at the same pace. Could there be a better setting for three Brazilian herpetologists fascinated by observing and photographing wildlife?
Departing from Buenos Aires, our first stop was approximately 500 km to the southwest, in the village of Sierra de La Ventana. There, we were able to discover a geological formation, homonymous to the village, which emerges abruptly from the Pampean plains*, and whose origin dates back to the Precambrian period, around 2.2 billion years ago. Much older than the Andes themselves, therefore. In this location, our main goal was to find the rare and endangered Casuhatien Anole (Pristidactylus casuhatiensis), a beautiful greenish lizard endemic* to the Ventania mountain chain. Despite our efforts over three days, we did not find any trace of this species. However, we did not leave without being rewarded by beautiful images of the landscape (Figure 2) and other species of lizards, such as the Cabrera’s Whiptail (Contomastix celata) and the William’s Marked Gecko (Homonota williamsi) (Figures 1 and 3)
Heading southwest for about 500 km, we enter a region with a semi-arid climate, in the municipality of General Roca. Semi-arid regions have specific ecological features that vary between those of humid and desert climates. They often have low rainfall rates-but not as low as those of a desert climate. Due to our limited time, and to escape the high noon heat, we only carried out a few hours of searches for reptiles in this location, during the late afternoon and evening. At the end of the afternoon, among the shrubby vegetation—with thorns of all imaginable sizes—, some individuals of Darwin’s Tree Iguana (Liolaemus darwinii) were crawling (Figure 4). Fast and with complete visual affinity to the environment, getting good pictures of them was really challenging. At night, the swift Liolaemus lizards gave way to the slow and patient South American Marked Geckos (Homonota horrida); equally charming, they were much easier to photograph (Figure 5). Finally, the night was crowned with the observation of a predation event, something always difficult to see in the field. In this battle of venomous arthropods, the Tarantula (Grammostola sp.) defeated its rival, a Yellow Scorpion (Brachistosternus sp.) (Figure 6).
We continued our journey towards the west. Traveling for just over 300 km and climbing more than 1000 m in altitude, we arrive at the municipality of Aluminé, more specifically at Villa Pehuenia, located in the Cordillera de Los Andes. There, closer to Chile than most other Argentine cities, the environment was also completely different from what we had seen before: the Villa Pehuenia is situated in the middle of a transition between Montane grasslands and Temperate broadleaf and mixed forests, with the stunning presence of large lakes and snowy hills, with a very beautiful appearance (Figure 7). As if in an attempt to match the beauty of the environment, the lizard fauna that we observe in the place is dominated by a particularly admirable species. It was not necessary to walk for thousands of meters to start finding specimens of the Thin Tree Iguana (Liolaemus tenuis). This skinny lizard is only found in that region of Argentina. It presents an outstanding combination of smooth sparkling scales, alternating greenish and bluish tones, from the anterior to the posterior region of the body (Figure 8). With a less striking color—although also beautiful—and a robust body covered with keeled scales, the Chilean Tree Iguana (Liolaemus chiliensis) (Figure 9) also brought us great joy by revealing its presence amidst the dense undergrowth.
Our next destination would be the town of Bardas Blancas. We drove for about 350 km northeastward and entered the province of Mendoza. Before starting the search for reptiles, we crossed the Paso Pehuenche, a customs house located between the department of Malargüe, in Argentina, and the province of Talca, in Chile. After fulfilling our legal obligations and receiving very good service, we mentioned to the customs inspectors the reason for our being there-to find and photograph a High Mountain Lizard (Phymaturus verdugo). The High Mountain Lizards are notable lizards for their herbivorous diet and flattened body in the dorsal-ventral direction, with spiny scales on the tail. They are found on the eastern and western slopes of the Andes, always in rocky places, where they shelter between rock crevices. In other words, in order to obtain good images, we would have to be sneaky to the point of preventing the lizards from escaping into a crevice. The reason behind this is, because of their flattened body, High Mountain Lizards are able to access deep caves in the rocks, making their observation unfeasible. We stopped the car on the edge of a stony hill and started searching. We noticed a considerable amount of lizard feces, which gave us immediate liveliness. It didn’t take long for us to find the first two individuals. Faster than us, however, they dispersed into nearby crevices, and we didn’t get a single image. But, as luck usually smiles on those who insist, we were successful on the third one. We saw the lizard a few meters away while basking in the sun (Figure 10). We approached slowly, without scaring it (unlike what we had done in previous encounters) and finally we were able to get great pictures of this beautiful reptile with a black head, greenish body, and yellow tail (Figure 11). With our mission accomplished, we returned through Paso Pehuenche. Surprisingly, the customs inspectors were waiting for us anxiously, curious to know if we had succeeded in finding that lizard. We tell them about the adventure, show some pictures taken and continue our journey.
After the first rewarding glimpses of the trip, we arrived at the Reserva Natural Villavicencio, located approximately 320 km northeast of Bardas Blancas. The reserve covers just over 60,000 hectares, among which three environments can be identified: Monte, Cardonal, and Puna, all composed mainly of grasslands and mountain scrub, with a very dry appearance. Despite the 21 species of reptiles found at the site, we were focused on finding the peculiar Patagonian Lancehead (Bothrops ammodytoides), the most southernly distributed snake species in the world. Although we were unable to find the target species, we came across an equally interesting snake. Amidst the multiple rocks and cacti of the place, a young individual of the Mousehole Snake (Philodryas trilineata) (Figure 12) was unsuspectedly crawling, possibly searching for small lizards. Interestingly, the Mousehole Snake also has an elongated, slightly upturned snout (although not as much as the Patagonian Lancehead), a unique feature within the genus Philodryas and only shared with its sister species*, Philodryas baroni. At the end of the day, in the Reserva Natural Villavicencio, our fate really seemed tied to “big noses”.
At the last part of the journey, we begin the return towards Buenos Aires (more than 1000 km southeast of the Reserva Natural Villavicencio). On the long journey back, we obviously couldn’t miss out on valuable opportunities to continue observing unique animals. Close to the municipality of San José, in a semi-arid and very hot formation, we found the most special Gecko of the trip, the Underwood’s Marked Gecko (Homonota underwoodi) (Figure 13). With psammophilous habits* light coloration and elliptical pupils, this species reminded us more of the lizard fauna of the Middle East than of its South American counterparts. Further on, in the imposing Sierras de Córdoba, we still had time for two memorable encounters. The first, a Painted Lancehead (Bothrops a f. diporus), the only venomous snake on the entire trip. With a vast repertoire of defensive behaviors and a lot of aggressiveness, photographing it was a spectacle in itself (Figure 14).
Finally, we had a comparable opportunity to Sierra de la Ventana (where the encounter with the Casuhatien Anole wasn’t possible). Although we were not dealing with exactly the same species, observing the Argentine Anole (Pristidactylus achalensis), with its greenish color and turquoise flanks in the males, would also be very rewarding. Taking precious tips from one of the guides of the Quebrada del Condorito National Park, we headed to the spot where it would be more likely found. And so, it was. Quickly, both under and on the rocks, we could find several individuals, varying from young to adults, and of both sexes (Figure 15).
This way, with many photos in our luggage and surely an even greater number of unforgettable memories, we ended our journey in Argentina and returned to Brazil. Lucky for us, the extraordinarily rich herpetofauna of South America still holds many secrets, most of which are completely unknown to our eyes. Sounds like a great excuse for future trips, doesn’t it?
Glossary:
*Pampean: originating in the Pampas region, which are open formations in the southern portion of South America.
*Endemic: restricted to a certain region.
*Psammophile: that lives associated with sandy formations.
*Sister-species: designation used to denote the groupings that include close-related species evolutionarily.
