This snake was captured close to the center of Covunco town in December, 2009. I used the date of 15 December as an approximate time for this observation, not sure of when it was found during this month.

These lizards were basking on the large rock outcrop behind the horses (picture 3).
Individual 1 (picture 1) is acquiring the adult male color pattern - a yellowish-green suffusion on the back and base of the tail. Individual 2 (picture 2), also a large male, still has the color pattern characteristic of juveniles and adult females.

These Phymaturus querque shared these rocks with individuals of Phymaturus zapalensis (next observation). This is another place where I have found both of these Phymaturus species in microsympatry (i.e., living together).

This lizard was observed basking on a block of large rocks (picture 2).

It is an adult female.

Also basking on this same rock pile were two Phymaturus querque (previous observation). This is a clear example of microsympatry between these two species of Phymaturus. I don't know how they differ from one another in other aspects of their ecology.

These lizards were observed basking on large rocks near to the entrance to the Minas de Paramillo.

The first animal (picture 1) is an adult male, with the yellow-greenish suffusion over its back and tail. The second individual (picture 2) is a smaller male, which still has the color pattern of adult females and juveniles.

This animal was observed basking on rocks in a boulder field near Laguna Batea.

It is an adult female. The pattern of this female is the same for all juveniles and for subadult males. Adult males have a different coloration.

This female has lost the basal part of her tail and regenerated a new length (pictures 1 and 2) that is distinct from the original tail that is covered with spiny scales.

These two lizards were found hiding under a flat rock near to the edge of this temporary pond (picture 4). A subadult Phymaturus zapalensis was under the same rock with these two Ph. querque!

The color pattern of the juveniles and adult females are very different from that of adult males.

These four Pleurodema larvae were captured on 6 April, 2023, in a stock, watering pond (picture 18). They were kept in an aquarium (photographed on 30 April, 2023), where they metamorphosed in May, 2023. The froglets are definitely Pleurodema bufoninum, and pictures of them will be uploaded at a later time.

The pond also was home to two species of notonectid bugs.

This is a hatchling Ph. trilineata. They were abundant in this area, as on the previous day, we saw three of them during one hour at a similar habitat, but a couple of kilometers to the south, in Chubut Province.
But, this animal was brought to me some octopus-fishing people who were searching for the mollusks out in the rocky pools exposed at low tide. When they gave me the snake they said that they had captured it while wading in the channel of the estuary that drains the Arroyo Sjenka (picture 4). This location surprised me a lot, as the water there would be a mixture of fresh and salt water, and could have been flowing quite rapidly. But, it is possible that when they found the animal the tide was rising and at equilibrium with the water flowing out of the arroyo, and so was not actually moving very much. I have never heard of this species found in water, even freshwater. The next day, my doubts were removed. Another couple of visitors to the place told me that they had seen a snake in these same waters earlier in the morning. They couldn't say what species they saw, but given that the Ph. trilineata were the only snakes that I saw here over the course of four days, it is probable that they too saw a swimming Ph. trilineata.

These lizards were basking on larger rocks that were part of a small hill that had been cut through for Ruta 23.

They were wary, and seemed to be much less abundant than L. bibronii here.

Both of these adults had lost parts of their tails (pictures 1 and 7). Pictures 4 and 9 show how the regenerated tails have different scalation than the unbroken tail.

Aguadita temporal, especie observada varias veces en la zona. Foto 1 corresponde a los huevos. Dejo otra observación para mostrar el amplexo y formación de huevos: https://www.argentinat.org/observations/102689277

This adult female was observed hopping around on the ground in a Nothofagus dombeyi/Chusquea culeou forest in the late afternoon. This was on a hillside that was at least 500 m away from the shores of Lago Perito Moreno.

This is an adult male.
I am pretty sure that this is a Batrachyla leptopus, because its skin is very rugose. Unfortunately, I did not take a picture of its ventral surface, where the color pattern is diagnostic for the species.

This is an adult female. I think it is possible that this is a B. antartandica, rather than B. leptopus as iNaturalist identifies it. The reason for this is that the B. leptopus that I just put up on the site, and captured at the same time and place, has skin that is much more rugose ("warty") than this animal. One difference between these two species is that B. antartandica has a smoother skin than does B. leptopus. I have capture a number of B. leptopus at another locality, and they had a much more warty skin, and the diagnostic belly coloration, than this specimen.
Unfortunately, I did not take a picture of the ventral part of the animal, where the coloration is diagnostically different between these two species.

This is an adult female. It was basking on rocky ground with steppe vegetation. Although this species has a big distribution in northern Patagonia, I find them incredibly hard to find - this is the only one in 18 years of working in this habitat! They can't be extremely rare if they have such a large distribution. I obviously don´t know what their behavior is like!
One of the most notable features of this species is the gray-and-white striping on the underside. Photos 1 and 4 show this coloration on the throat, but it continues down onto the belly region. What this color pattern serves for, where it is pretty much invisible from above, is unknown to me.

This is a subadult male.
This is an adult female. The locality where I found this animal is about 20 km SW of where Cei et al. (2003) collected the type specimen for their species Diplolaemus sexcinctus.
Recent molecular studies by Femenías et al. (2020) show that there may be at least six "cryptic species" within this species-complex. Detailed studies of the morphology of the group will be needed to corroborate these molecular studies.
For now, I think that this specimen belongs in the species Diplolaemus sexcinctus "sensu stricto", i.e., belonging to the population that Cei et al. described in 2003.

This is an This is a juvenile male.
Recent molecular studies by Femenías et al. (2020) show that there may be at least six "cryptic species" within this Diplolaemus sexcinctus species-complex. For now, this specimen belongs in their species "Diplolaemus sexcinctus lineage 4". Detailed studies of the morphology of the group will be needed to corroborate these molecular studies and to formally describe them as a new species.

This is a sub-adult female.
Recent molecular studies by Femenías et al. (2020) show that there may be at least six "cryptic species" within this Diplolaemus sexcinctus species-complex. For now, this specimen belongs in their species "Diplolaemus sexcinctus lineage 4". Detailed studies of the morphology of the group will be needed to corroborate these molecular studies and to formally describe them as a new species.

These three photos show two interesting aspects of R. arenarum populations in Mendoza Province.
Photos 1-3 show irregularly arranged, bright yellow spots on the back and sides of this animal. Jose Cei (1959) made observations on the number of animals that had these spots. He found that in Mendoza and adjacent San Jose Provinces, up to one-quarter (25%) of a local population may be spotted. In nearby provinces like San Luis and Cordoba, none, or singleton spotted animals were found. So, there is a geographic part to what exists in this wide-spread species. What is the meaning/importance of these bright spots? In some strains of laboratory mice, similar, irregular spotting is well understood as happening because of cells are mutated to lack pigment (melanin) while the early embryo is forming the layer of cells that will ultimately become the skin of the mouse. The mutant cells multiply and ultimately form patches of of white skin and hair. Presumably, something like this is happening here, with clones of yellow-pigmented cells appearing on different parts of what will become the dorsal skin during embryological development. Nothing more than Cei's report seems to have been published about the biology of this unusual coloration.
Photos 2 and 3 show the second unusual condition in these Mendoza-San Jose toads - a reflex that Cei called "hypnotic" and "spastic". When one of these toads is disturbed, it assumes this position, with its legs pulled in close to the body, the back curled over, and the eyes closed. The animals remain like this for many minutes. Cei found that the frequency of this behavior was much higher than yellow-spotting, reaching 60 percent in some of these same Mendoza/San Jose populations. It was absent in populations from other populations. The behavior is probably an adaptive, defense against attack by predators. Making the body as compact as possible, and secreting the noxious fluids from the large glands on the dorsal surface presumably keeps predators from attacking and hurting the animals. But again, I haven't found further experimental studies that would support, or not, this claim.
This common toad is full of interesting things for naturalists to study!

This species name is doubtful for this animal. In a good molecular study by Blotto et al. (2013) they found that the DNA similarity of animals from nearby Lago Paimún were in a separate, but adjacent lineage to Chilean E. roseus. More studies may show that these Neuquén Eupsophus should be classified as a new species.

This animal is an example of the aquatic phase of this species. In nearby Laguna Blanca, the introduction of predatory fishes resulted in the extinction of this species in that lake in the 1980s. In nearby, smaller lagunas, where the fish were not introduced, this aquatic phase still occurs.
In this aquatic phase the animals develop the highly vascularized skin (photo 2) that probably allows the frogs to live completely submerged in the water. This is the case with a similar, highly vascularized Telmatobius frog that lives in Lago Titicaca in Bolivia/Peru. The vascularization is reversible and the animals can survive on land.

In 1982 these aquatic frogs were very abundant in Laguna Blanca, with as many as a dozen or so hiding under rocks in the shallow water at the edge of the lake. Within a couple of years they had all been eaten by the introduced trout and "trucha criolla" (Percichthys trucha). The extinction of the frogs led to an irreversible collapse of a unique aquatic ecosystem.

This species name is doubtful for this animal. In a good molecular study by Blotto et al. (2013) they found that the DNA similarity of animals from nearby Lago Paimún were in a separate lineage from Chilean E. roseus. More studies may show that these Neuquén Eupsophus should be classified as a new species.

Photo 2 shows the "protective" posture that this frog is in: hunched down with the hands partly covering the closed eyes, and rear part of the body raised up. This posturing protects the head and at the same time presents the dorsal "eyes" (enlarged lumbar glands).
It would be interesting to know if these lumbar glands have a noxious secretion, or function to make false "eyes", which might cause a potential predator to decide to go away.

These photos show two Black rats (Rattus rattus) that I trapped in a compost pile in the barrio. They are of interest because they represent examples of a genetic polymorphism in coloration in the same species, and could cause confusion in identifying rats from around houses.
If you look at photos 3 and 4, where the two animals are side by side, you can see the major color differences between the two animals (gray versus brown). If you didn't know, you might think that these were two different species. That is not the case - they are the same species, and could even have been born in the same litter. The gray color phase (called the "rattus" phase) is the one that is most common in this part of Argentina. The brown rat (the "alexadrinus" phase) is less common, comprising (maybe) 20 percent of these rats in the Bariloche area.
The brown phase rat looks superficially like another species: the Norway rat (Rattus norvegicus) that is also present in Bariloche. But, the Norway rat is much stouter than the Black rat, usually larger, and has a stubby tail, in contrast to the long, tapering tail of the Black rat.

This gecko was hiding underneath a fiber-glass bag (photo 2) left in this Larrea-dominated habitat (photo 3). In late October, 2021 (springtime), there were about 7 Agathemera millepunctata under this same bag.
Photo 1 is a "posed" picture of the animal placed on a dead branch near the bag.