Southwestern Peru Research Articles

First record of <i>Abrothrix olivacea</i> (Waterhouse, 1837) in Peru based on historical material from Tacna

Abrotrichini is the sigmodontine tribe with the fewest species in Peru, known only from two species: Abrothrix andina and Ab. jelskii, both distributed in the high Andean regions of Peru above 3000 m in altitude. A detailed review of the morphology of historical specimens collected in the Tacna department and identified as Akodon mollis was conducted. As a result, we found that the examined specimens corresponded to Abrothrix olivacea, a species previously known only from Chile and Argentina. This discovery represents the first record of this species in Peru, extending its distribution range 165 km north of its previous northernmost record in Quebrada Camarones, Arica-Parinacota, Chile. Furthermore, this finding significantly reduces the distribution range of Akodon mollis to the northwestern region of Peru. We also provide key craniodental characters to differentiate species of Abrothrix and Akodon in southwestern Peru and northern Chile. For Peru, this record increases the diversity of mammals to 588 species and rodents to 201 species. In the case of the Tacna department, mammalian diversity increases to 47 species. This work highlights the value of natural history museum collections in enhancing our understanding of species diversity.

Regional Controls on Climate and Weather Variability on the Southwest Coast of Peru

Southwestern Peru has an arid climate typical of subtropical west coasts bordering cold ocean currents. Mountain runoff is barely able to sustain urban needs and motivates this research. Using high-resolution satellite reanalysis products, the meso-scale climate and weather variability are explored via point-to-field regression. A time series spanning 1970–2022 of Tacna area (18 S, 70.2 W, 570 m) rainfall, potential evaporation, wind, and weather parameters were evaluated for thermodynamic and kinematic features. Although sea breezes draw marine air inland, they simultaneously generate low-level divergence and subsidence aloft. Potential evaporation in early summer causes water deficits that are rarely offset by late summer runoff from the Andes Mountains. Winter (May–September) showers from passing cold fronts are more frequent during El Niño. Warming of the tropical east Pacific accelerates subtropical westerly winds that lift over the coastal plains. Quasi-stationary Rossby wave patterns amplify transient troughs at 70 W, but the winter showers rarely exceed 4 mm/day due to low-level stability from negative heat fluxes over cool seawater offshore. Two winter wet spells were studied using satellite and surface data (July 2002, July 2009). Light showers were prominent in elevations from 400 to 900 m. An early summer dry spell was considered (November 2020), wherein southeast winds, coastal upwelling, and low dewpoint temperatures coincided with La Niña conditions. A rain-gauge transect showed that summer convection stays east of the Andes escarpment and seldom benefits the coastal plains. Thus, water resources in Tacna are strained beyond the carrying capacity.

New age constraints on the break-up of Rodinia and amalgamation of southwestern Gondwana from the Choquequirao Formation in southwestern Peru

Abstract The Choquequirao Formation is a >3 km-thick amphibolite-grade succession that outcrops in the Central Andes of southern Peru. To constrain its age and tectonostratigraphic setting, detrital zircon and metamorphic zircon, titanite, and rutile U–Pb isotopic analyses were conducted. Mantle-derived c. 640 Ma detrital zircons constrain the maximum age of the lower part of the succession and 550–490 Ma metamorphic zircon domains constrain its minimum age. The absence of early Paleozoic detrital zircons suggests that deposition predated early Paleozoic orogenesis in southwestern Gondwana. The close similarity of detrital zircon age spectra to those from sediments deposited on the Arequipa basement suggests that the Choquequirao Formation was deposited on the Arequipa Terrane. Metamorphic titanite dates are highly overdispersed, yet they overlap with c. 460 Ma peak metamorphism recorded by metamorphic zircon. Pb-loss pathways displayed by metamorphic titanite have a lower intercept that overlaps with c. 325 Ma metamorphic rutile, which corresponds to Hercynian orogenesis. A poorly constrained upper intercept of c. 510 Ma may correspond to Pampean and/or early Famatinian orogenesis. We interpret the Cryogenian–Ediacaran Choquequirao Formation as having been deposited during the opening of the Palaeo-Iapetus (Puncoviscana–Clymene) Ocean between eastern Arequipa and southern Kalahari prior to the subsequent collision with southwestern Amazonia during the Pampean Orogeny.

Distribution extension of Lasiurus arequipae Málaga, Díaz, Arias & Medina, 2020 (Chiroptera, Vespertilionidae) and contributions to its natural history

The recently described bat Lasiurus arequipae Málaga, Díaz, Arias & Medina, 2020 is endemic to Peru. Lasiurus are­quipae is currently known to occur at two localities in the department of Arequipa and one locality in the department of Tacna in southwestern Peru. Here, based on morphological and molecular data, we present a fourth locality that represents the southernmost record of this species and extends its known range 62 km south from the nearest locality in Tacna. Additionally, we provide information some aspects on the natural history and acoustic profile of L. arequipae.

Ultrastructure, composition, and 87Sr/86Sr dating of shark teeth from lower Miocene sediments of southwestern Peru

Bioapatite of fossil bone and teeth is susceptible to alteration and ion exchange during burial and diagenesis, varying its Sr content through the geological time. Nevertheless, fossil shark teeth are a powerful proxy for both chronostratigraphic and paleoecological reconstructions, thanks to the presence of the enameloid, a hard outer layer consisting of resistant fluorapatite crystallites. Here, we analyze fossil shark teeth from the Miocene sediments of the Chilcatay Formation of the Pisco Basin (southwestern Peru) with the aim of dating poorly constrained strata in this region. (Ultra)structural and compositional analyses of fossil lamniform and carcharhiniform teeth are performed through macroscopical observations, optical microscopy and SEM-EDS for evaluating the preservation state of the collected teeth. Shark teeth display a compact and well preserved outer enameloid layer formed by highly ordered bundles of crystallites that is distinctly separated by a more porous and heterogeneous inner core of dentine featuring diagenetic artefacts and microborings. Compositional mapping highlights differences in the distribution of Ca, P, F, and S in the enameloid and dentine, and chemical results show a Sr content that is consistent with the range reported for extant shark teeth. The best preserved teeth were selected for Strontium Isotope Stratigraphy (SIS), measuring the 87Sr/86Sr values in the enameloid and obtaining numerical (absolute) age estimates. In the Ica River Valley, SIS dates the Chilcatay strata to the Burdigalian (between 19.1 and 18.1 Ma), in agreement with previous radiometric, isotopic and biostratigraphic ages obtained in the same region. At Media Luna, the Chilcatay strata are dated herein for the first time, resulting in a slightly older age of 21.8–20.1 Ma (late Aquitanian–early Burdigalian). These results strengthen the notion that the Sr-ratio of shark teeth can be successfully applied for obtaining reliable age estimates via SIS.

Concentrated Solar Power (CSP) Systems to Solve the Problem of the Increasing in Electricity Demand in the Summer Season in Iraq

Concentrated solar power (CSP) is the conversion of the sun's energy into thermal energy by concentrating the solar radiation by means of mirrors or any other optical element such as lenses on a receiver containing a liquid such as water, molten salt, industrial oil or compressed gas to provide heat for heating and for industrial purposes or to generate steam that rotates a turbine to produce electricity. CSP plants may contain thermal storage units to provide electrical and thermal energy during the night or when the weather is cloudy. Concentrated thermal and electrical energy generation requires high direct solar radiation (DNI) which represents 90% of the sunlight on a sunny day and its value is neglected on a cloudy day, so (CSP) is effective in the sun belt regions, which are located at latitudes between 15 and 40 degrees north and south of the equator, these regions include: the Middle East, North Africa, South Africa, India, southwestern United States, Mexico, Chile, Peru, eastern China, Australia, southern Europe and Turkey. Also, solar radiation is high at high latitudes, as dispersion is low. The best areas to install CSP plants are the areas where direct solar radiation (DNI) is greater than (2800 kwh/m2 per year). The time taken to build CSP plants is from (1-3) years depending on the size of the plant, and its operational life is more than 30 years. The area needed by these plants is 2 hectares per megawatt. This article highlights on the systems for generating electric power from concentrated solar energy and presents the different fluids used in heat transfer, as well as the methods of thermal storage.

Rainy season precipitation forecasts in coastal Peru from the North American Multi‐Model Ensemble

AbstractWe assessed operational forecasts of rainy season (January–March [JFM]) precipitation over coastal Peru from seven global climate models (GCMs) in the North American Multi‐Model Ensemble (NMME) from 1982 to 2020. Similar to previous representations by GCMs, regional climate models, and atmospheric reanalyses, the NMME models produce excessive precipitation (more than twice the observed values) over all of coastal Peru. Based on a set of commonly used metrics (correlation, mean error, RMSE, and Heidke skill score), there is a wide range in accuracy among the NMME models. As expected, forecast accuracy degrades with increasing lead time from December to July, but the rate of decline varies greatly by region and among models. The cause(s) of differences in model performance remains unclear, but resolution does not appear to be a significant factor. Highest forecast skill is found for southwestern Peru (correlations with observations are significant at all lead times), probably because of its stronger relationship between rainfall and El Niño–Southern Oscillation (ENSO), and lowest skill occurs for west‐central Peru (insignificant correlations at all lead times). The distribution of interannual rainy season precipitation in northwestern Peru is extremely positively skewed (skewness >2), making evaluation of forecasts difficult from only a few years that deviate strongly from the mean. Improved correlations with observations across regions are generally found by subsetting multi‐model mean forecasts using the better‐performing models. Over northwest Peru at short lead times, NMME rainy season precipitation forecasts outperform a simple statistical correlation between JFM rainfall and ENSO, but not at longer leads, while NMME's forecasts for west‐central Peru underperform statistical correlations at all lead times. Over southwest Peru, the NMME models are consistently more skilful than a statistical correlation, and these differences become larger with increasing lead time.

Geology and geochronology of the Don Javier Cu-Mo porphyry deposit, southern Peru

The Don Javier porphyry Cu-Mo deposit is located in the Yarabamba district of the Arequipa region, Peru, which represents the northwestern end of the Paleocene-early Eocene Cu belt of the central Andes, extending from northern Chile into southwestern Peru. The deposit occurs around the contacts of a dacite porphyry stock emplaced into the pre-mineralization and Yarabamba granodiorite batholith. The intrusions display a telescoped sequence of alteration, from shallow sericitic to deeper chloritic-sericitic, with minor remnant potassic assemblages, which are surrounded by propylitic zones. EB-, M-, EQ-, SQ-, and D-type veinlets occur in all alteration zones. The higher Cu and Mo grades are mainly associated with the widely distributed sulfide-quartz veinlets within the potassic and chlorite-sericite overlapping zones. The mineralized zone measures ∼500 m in width (NE-SW) by ∼800 m in length (NW-SE). Uranium-Pb zircon ages show that the Yarabamba granodiorite plutons were emplaced at ∼ 64.6 Ma and subsequently intruded by the inter-mineralization dacite porphyry intrusions at ∼ 59.9 to 59.5 Ma. Molybdenite Re-Os ages indicate that the deposit formed between ∼ 60.5 and 59.6 Ma. Younger molybdenite Re-Os ages (∼45.4 to 44.4 Ma) obtained in the deep parts of the altered rocks suggest that the deposit might have been overprinted by later hydrothermal activity in the Eocene. The success of exploration at Don Javier emphasizes that traditional methods such as geologic and geophysical mapping followed by timely drilling tests can still be effective in a mature metallogenic belt.

Hydrogeochemistry of the Thermal Springs of Pojqpoquella and Phutina, Puno, Peru

This paper deals with the results of a hydrogeochemical study of two thermal springs that originate from in very high altitudes in southwestern Peru with outflow temperatures of maximal 38,4 °C and flow rates of 1.08 - 2.02 l/s. Water samples from the Pojqpoquella and Phutina geothermal wells, were collected during the period between September 2018 and January 2019 in the main area of Puno. Chemical types of the thermal spring are Na+, Ca2+, Cl- and in Ayaviri and Putina. According to the Piper and Schoeller diagrams for the Pojqpoquella thermal spring water is classified as Na++ K+ (75 %) and Cl- (60 %) type water while that of the Phutina thermal spring is classified as Na++ K+ (76 %) and Cl- (72 %) type water. The electrical conductivity (EC) values for the Pojqpoquella and Phutina thermal spring waters is 2160 - 3142 μS/cm and 3160 - 3184 μS/cm, respectively, the thermal spring waters have a high electrical conductivity which shows that it has interacted with the host rock for a long time. The reservoir rocks of the Pojqpoquella thermal system consist of a red sandstones and conglomerate rocks while the reservoir rocks of the Phutina thermal system consist of a thick sequence of cretaceous rocks.

Hostplant and last instar of Amastus walkeri (Rothschild, 1922) from southwestern Peru (Lepidoptera: Erebidae, Arctiinae)

The hostplant, Schinus molle L. (Anacardiaceae) and the last instar of the Arctiinae Amastus walkeri (Rothschild, 1922) are reported for the first time. Several caterpillars with abundant setae and gregarious behavior, were observed feeding on the leaves of Schinus molle L. in the department of Arequipa, southwestern Peru. Ten caterpillars were collected and raised in laboratory condition. Two adults were recovered. According to the external morphology of the adults, they correspond to the species identified as Amastus walkeri (Rothschild).

Six new species of spider beetles (Coleoptera: Ptinidae) in the genus Cordielytrum Philips.

Six new species of spider beetle are described from southwestern Peru: Cordielytrum silvae, sp. n., C. inca, sp. n., C. fimbriatum, sp. n., C. obscurum, sp. n., C. adustum, sp. n., and C. globuloides, sp. n. The potential for undescribed diversity in this genus is discussed, as well as the geographic distribution and biology of species.

Comentarios y adiciones sobre especies recientemente descritas del grupo Liolaemus montanus procedentes de Perú

In this paper, information is added and comments are made about two recently describedPeruvian species of Liolaemus from the montanus group: L. balagueri and L. qalaywa. WhenL. balagueri was described, differences from L. nazca was based on a phylogenetic analysis of asingle mitochondrial locus, but without including phenotypic diagnostic traits that might differentiatedthem. On the other hand, L. qalaywa description was based upon specimens fromApurimac department and intraspecific variation in meristic traits were missing. In this study,we added a molecular and morphological analyses between L. balagueri and L. nazca, supportingmore rigorously the separation between these two taxa. In addition, the geographic rangeof L. qalaywa is extended to Cusco department (southwestern Peru), intraspecific variation ofmorphological characteristics and geographic information up to 79 specimens are included,and the conservation issues of this species is commented.

An Endemic and Endangered New Species of the Lizard Liolaemus montanus Group from Southwestern Peru (Iguania: Liolaemidae), with a Key for the Species of the L. reichei Clade.

The southwestern Andes of Peru harbor a hidden taxonomic diversity of reptiles. We describe a new species of Liolaemus Wiegmann (Iguania: Liolaemidae) from xerophytic environments of the southwestern slopes of the Andes of Peru, 2,400-2,900 m asl. The new species, previously considered to be a population of L. insolitus Cei, exhibits unique diagnostic characters of morphology, scalation and color pattern, and molecular evidence that suggest that it belongs in the Liolaemus montanus species group and the L. reichei clade. Moreover, the species is endemic to the eastern slopes of La Caldera batholith in the Department of Arequipa, southern Peru. We also provide information on the conservation status of the species and suggest it be included in the IUCN red list of the threatened species as endangered (EN). A key for the species of the L. reichei clade is provided.

Valoración económica del secuestro y almacenamiento de carbono en la puna seca del suroeste del Perú

In the face of a global warming scenario, carbon capture and storage has become an international strategy to mitigate the effect of greenhouse gases. Oceans and Tropical forests are considered the largest carbon sinks in the world, however a few studies have evaluated the relative importance of other plant formations as carbon sinks in the Neotropical Region. This study documents the economic value of carbon capture and storage by five plant formations representative in the Puna Seca of southwestern Peru. Sampling plots were established to estimate the biomass contained in seedlings of Pajonal, Tolar, Bofedal, Yaretal and Quenual, in Salinas y Aguada Blanca National Reserve (Arequipa, Peru). Later, carbon stored and carbon captured as CO2 was estimated. The Peruvian average carbon exchange price per ton of CO2 was used for the economic evaluation of environmental services. It was found that the Reserve contains at least 13,507,104.16 equivalent metric tons of CO2 worth U$D 86,310,395.58. Bofedal was the main vegetal formation that contributed in these values (52.48 %), in spite of being little represented in the total area of the Reserve (2.58 %). It is expected that the economic value obtained will serve as a frame of reference in decision-making for various purposes (environmental awareness, environmental management instruments, national accounting, among others).

Smooth flows? Hydrosocial communities, water governance and infrastructural discord in Peru’s southern highlands

ABSTRACTThe article examines how the design and governance of Peru’s water infrastructure shape the social practices and cultural values stakeholders engage in and draw on when negotiating water rights in a year of drought. Reviewing ethnographic data on a large irrigation project in south-western Peru, we discuss how the project both perpetuates power relations between water experts, authorities and users and creates room to challenge its hierarchical organization. The project’s infrastructural assemblage of state and community canals offers an interesting case to explore how the stakeholder cooperation encouraged by Peru’s water law produces hydrosocial communities.

Contributions to the natural history of Mormopterus kalinowskii (Chiroptera: Molossidae) in the southwest of Peru

Mormopterus kalinowskii, is an insectivorous species restricted to the Andean western slopes of Peru and Chile, it is rare and has very scarce available information. We evaluated sex ratio, roost use, and relationship between reproductive patterns and monthly seasonal variation throughout a 13-month period. In addition, we performed the first description and characterization of its echolocation calls. The study area was located in the Ite Valley, Tacna department (southwestern Peru) at the northernmost part of the Atacama Desert, one of the driest deserts in the world. Bats were caught using mist-nets. Sex ratio in the population was calculated from all individuals captured, and its difference with regard to a 1:1 ratio was assessed through a Binomial Coefficient Test. Roost use was assessed through observation and inspection of the study area. Pearson and Spearman correlation coefficients were calculated to establish the relationship between the number of captures and temperature and precipitation data. Echolocation calls were recorded using a Petterson D240x Ultrasound detector plugged to a digital recorder. Spectrogram displays of recorded calls allowed describing structural patterns within echolocation calls and to measure frequency and time parameters. 79 individuals of M. kalinowskii were captured; 30 males and 49 females. Sex ratio obtained, 1:1.63, evidenced more females in the study area. M. kalinowskii uses crevices as roosts and has a single reproductive cycle per year. Higher capture rates are correlated with temperature (r = 0.526), but not precipitation (r = 0.096). Calls in search phase exhibited long duration pulses and a descending quasi-constant frequency (QCF) component from 39 to 33 kHz, reducing length and increasing bandwidth when attempting to catch prey. The sex ratio, 1:1.63 (≈ 2), suggests that M. kalinowskii is a polygamous species, as occurs in the others molossids, whereas the single annual reproductive cycle shown by M. kalinowskii would indicate a seasonal monoestrous reproductive pattern. Echolocation calls share several traits observed in other molossids; however, the frequency values for M. kalinowskii search phase pulses could be the highest recorded among the molossid bats of the Pacific coastal desert, allowing them to detect smaller prey as a strategy to mitigate food competition among insectivorous bats in arid environments.

“Our gold is dirty, but we want to improve”: Challenges to addressing mercury use in artisanal and small-scale gold mining in Peru

Mercury use in artisanal and small-scale gold mining (ASGM) has captured global attention and concern for decades. Policy makers and development practitioners routinely promote awareness campaigns and technical assistance to address mercury use in ASGM; however, this focus obscures other barriers that stand in the way of addressing mercury emissions from the sector. Focused on the town of Relave, in the Ayacucho Region of Southwestern Peru, this paper examines the perspectives and practices of some of the community members who are involved with ASGM activities. It highlights their own views of the challenges related to ASGM and explores the ways in which they are addressing these challenges. Despite their efforts, this paper reveals that there are two key barriers to controlling mercury use in Relave, which lie outside of the communities’ lack of awareness and technological capabilities. These include the deprioritization of mercury use and pollution among community members as compared to other community and public health concerns and inequities in the supply chain that position miners and mineral processors with little to no control over the distribution, use, and emissions of mercury. The implications of these findings for policy decisions, regulatory schemes, and development initiatives are not only relevant to Peru, but are also significant for other countries committed to addressing mercury emissions from ASGM.

Palaeoenvironmental analysis of the Miocene barnacle facies: case studies from Europe and South America

Abstract Acorn barnacles are sessile crustaceans common in shallow-water settings, both in modern oceans and in the Miocene geological record. Barnacle-rich facies occur from polar to equatorial latitudes, generally associated with shallow-water, high-energy, hard substrates. The aim of this work is to investigate this type of facies by analysing, from the palaeontological, sedimentological and petrographical points of view, early Miocene examples from Northern Italy, Southern France and South-western Peru. Our results are then compared with the existing information on both modern and fossil barnacle-rich deposits. The studied facies can be divided into two groups. The first one consists of very shallow, nearshore assemblages where barnacles are associated with an abundant hard-substrate biota (e.g., barnamol). The second one includes a barnacle-coralline algae association, here named “barnalgal” (= barnacle / red algal dominated), related to a deeper setting. The same pattern occurs in the distribution of both fossil and recent barnacle facies. The majority of them are related to very shallow, high-energy, hard-substrate, a setting that represents the environmental optimum for the development of barnacle facies, but exceptions do occur. These atypical facies can be identified through a complete analysis of both the skeletal assemblage and the barnacle association, showing that barnacle palaeontology can be a powerful tool for palaeoenvironmental reconstruction.

Short Communication: Second record of Eumops chiribaya (Chiroptera, Molossidae) in Peru

Medina CE, Díaz DR, Malaga BA, Medina YK, López E. 2018. Short Communication: Second record of Eumops chiribaya (Chiroptera, Molossidae) in Peru. Biodiversitas 19: 1979-1984. The bat Eumops chiribaya was recently described from southwestern Peru, based on unique specimen collected in the coastal desert of Moquegua Department. Herein, we document the second record for the country based on a specimen collected in Arequipa Department. This specimen is described in detail and compared with the holotype of E. chiribaya. This record represents a significant extension of the geographic range for this species, both in latitude and elevation, and it show the high diversity of bats living in the coastal valleys of southwestern Peru. Our record adds one genus and species to the Arequipa Department, totaling 17 bat species in the Department.

Xanthotropis, a new genus in the Neotropical millipede subfamily Aphelidesminae (Diplopoda, Polydesmida, Aphelidesmidae).

The monotypic taxon Xanthotropis n. gen. is established to accommodate Haematotropis media Golovatch, Hoffman Spelda, 2004, known only from the vicinity of Manaus, Brazil, as it is incompatible with both its originally assigned genus and Aphelidesmus Brölemann, 1898, a suggested alternative. Xanthotropis is defined primarily by minute teeth on paranota 2-4, a sublinear posterior margin of the telson, and an elongated, distally expanded/laminate acropodite. The Aphelidesmidae Brölemann, 1916, range from northeastern Mexico and Tobago to northern Brazil and southwestern Peru; a questionable more-northerly record, from Monterey, Mexico, requires verification with fresh material. One of two families of the polydesmidan superfamily Platyrhacoidea (Leptodesmidea), Aphelidesmidae comprises two subfamilies, the nominate and Amplininae Hoffman, 1954. The latter has been addressed by several authors, and we here review Aphelidesminae by providing full synonymies, a literature review, and a key to its four genera: Aphelidesmus Brölemann, 1898; Haematotropis and Ochrotropis, both by Jeekel, 2000; and Xanthotropis n. gen.