Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The collections of the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (MACN) not only reflect biodiversity but also the historical impact of scientific institutions on the evolution of knowledge. Through them, one can observe the transformation of research, conservation, and outreach practices, shaped by the political and social contexts of each era. A representative example of this legacy is the collection of fish gathered during the 1938 and 1939 expeditions to Saint Helena and Ascension Islands in the South Atlantic, carried out as part of the efforts of the Argentine Merchant Navy. The ship Sentinel II, originally intended for the installation of underwater cables, played a key role in these expeditions. After being acquired by the Compañía Argentina de Navegación y Comercio África-Río de la Plata, it was used for lobster and exotic fish fishing while also collecting scientifically valuable samples for the Museum. Between 1938 and 1939, the fish collection of the MACN’s Ichthyology Division received around 33 lots of fish related to these voyages. This article highlights how the study of these fish, traditionally approached from a biological perspective, offers a unique opportunity to explore a little-known event in the history of the Museum and the Argentine Merchant Navy.

The purpose of this work is to present a preliminary list of the taxonomic composition with comments on the biological and ecological characteristics of the Heteroptera present in a pastoral ecosystem of the locality of Santa Catalina, Jujuy, Argentina. A preliminary list of 17 species belonging to three infraorders and six families is presented: Coreidae, Lygaidae, Pentatomidae and Rhopalidae (Pentatomomorpha), Miridae (Cimicomorpha) and Saldidae (Leptopodomorpha). Four species are new records for the province of Jujuy. Host plant data are provided for nine species.  

We report the first record of Ischnothele annulata (Mygalomorphae: Ischnothelidae) for the province of San Juan, Argentina. This finding extends its known distribution, marking a new western limit with the nearest locations being Chepes and Quines in La Rioja and San Luis, respectively. The observed population is within the arid region of central-western Argentina, at the ecotone between the Arid Chaco and the Monte Desert.

Hydra viridissima (Pallas, 1766) is reported for the first time in the city of Corrientes, Argentina, in a freshwater body. The specimens were attached to the roots of native aquatic plants and were found to be undergoing both sexual reproduction, with the presence of ovary and testis, and asexual reproduction through budding. The species was notrecorded again in this body of water during 2023 and 2024.

Characidium is the most diverse genus within the family Crenuchidae, with a total of 88 valid species, although there is evidence that it is probably a polyphyletic group. Recent expeditions to northern Uruguay revealed the first records of Characidium serrano Buckup & Reis, 1997, extending its distribution in about 300 km to the south and allowingto consider it as an endangered species for Uruguay, considering its restricted distribution in the country. Different phylogenetic reconstructions and comparisons based on COI (Model-based analysis, Parsimony analysis and Evolutionary Divergence between sequences) of new sequences with those previously published indicate: 1) a closer phylogenetic relationship of C. serrano with C. clistenesi or alternatively with (C. rachovii + C. orientale) than with C. pterostictum and 2) non-coincident topologies that in all cases suggest the non-monophyly of Characidium.The analyzed sequences of the genus Characidium formed 9 main stables groups that are obtained in each of the analyzes carried out, which were also recovered in studies previously performed by other authors, but with general topologies not coincident and poorly supported in their basal nodes.

Phalloceros mimbi sp. nov. is described from specimens collected in the floodplains of the middle and lower Uruguay River in Uruguay (Río Negro and Salto Departments) and Argentina (Entre Ríos Province). This species belongs to the P. harpagos species complex and is diagnosed by the following unique combination of characters: 1) presence of a symmetric hood-like structure located immediately anterior to the urogenital papilla in females, 2) absence of large papillae at the mandibular symphysis of large adult females, 3) possession of well-developed hooks positioned in distal portion of gonopodial appendices of males and4) lateral spot usually present in both sexes. To date, P. mimbi has not been found coexisting in sympatry with other Phalloceros species. The geographically closest species is P. caudimaculatus, who differs from P. mimbi by the absence of hooks in gonopodial appendix in males. Two of the three known populations of P. mimbi are relatively protected from the main threats to the species. However, conservation initiatives should consider its presence and ensure that it receives the necessary attention; considering that its global distribution occupies less than 200.000 km2 and its occurrence area represents less than 10% of the national territory it must be considered a priority for conservation and an Threatened Species for the species list of Sistema Nacional de Áreas Protegidas (SNAP) of Uruguay.

The research on the population dynamics of vicuñas in three habitats within the regions of Puno and Moquegua aimed to: a) Quantify the population fluctuation of vicuñas and flora diversity in the Sandy, Wetlands, and Grasslands habitats. b) Estimate the population density of vicuñas and flora biomass in the Sandy, Wetlands, and Grasslands habitats. To conduct this investigation, linear transect methodology was employed, utilizing the Hayne estimator for each mentioned habitat and random quadrants. The results revealed a trend towards an increase in the number of individuals and family groups in the sandy dune habitat, while lower values were recorded in the wetlands and grasslands habitats. However, it is worth noting that population density was higher in the Wetlands habitat, with a value of 0.699 indiv/ha, followed by the Sandy habitat with 0.275 indiv/ha, and the Grassland with 0.163 indiv/ha. Additionally, a higher number of females than males were observed, with groups of up to 34 male individuals forming herds. Furthermore, the Sandy habitat exhibited lower flora diversity and biomass (1653.89 kg), whereas greater flora diversity and biomass were recorded in the wetlands (24773.76 kg), and the Grasslands calculated at 25524.48 kg. These findings provide valuable information regarding the population dynamics of vicuñas, flora diversity, and biomass in the analyzed habitats, crucial for their conservation and proper management in the regions of Puno and Moquegua.

Bats use several types of shelters, both natural and artificial, which allow them resting, reproduction, breeding, among other fundamental activities. Some shelters can be used by two or more species, even from different bat families. In this paper, we report the first record of Molossops temminckii for El Palmar National Park (PNEP, Entre Ríos, Argentina) and the use of billboard posts as artificial shelters. Two posts were recorded being used as shelters by the species and in one of them we found a mixed colony of M. temminckii and Myotis sp. (Myotis cf. nigricans). The use of posts as artificial shelters may be related to the ease of occupying previously constructed holes, even in natural environments such as protected areas with a large availability of natural shelters. This work also allowed increasing the known number of bat species in the PNEP to six species.

We studied the Austral Rail (Rallus antarcticus, Vulnerable, BirdLife 2025) in a 22.5-hectare aquatic reedbed in Santa Cruz Province, Argentina, following the removal of cattle and the restoration of vegetation cover. Using a combination of transmitters, camera traps, and Tomahawk traps, we established that the Austral Rail has two breeding events per year and constitutes a partially migratory population. We also obtained missing biometric and biomass data. During the study, it was possible to learn about their behavior, activity schedules, reproductive phenology, and other aspects such as feeding and parental care.The proportion of individuals that abandon their territories during the winter (partial migrants) return in spring,  stablishing new territories each year and changing locations. Rails are seen much less frequently in winter, partly because they vocalize less, and partly because the reed bed freezes and no individuals are seen, while in areas where it does not freeze, individuals concentrate, but part of the population disappears.

Coloration patterns in wildlife species are basic adaptations for the survival of populations, acting in camouflage, mimicry, sexual selection and thermoregulation. Atypical cases of coloration of taxa are also common, such as leucism, which is a hypopigmentary variation of the skin or fur, which occurs throughout or partially on the body. Leucism has been associated with environmental factors, such as anthropized habitat, low-quality diet, radioactive contamination and effects of anthropogenic actions. Likewise, individuals with leucism are more frequent in small and isolated populations since inbreeding increases the possibility of recessive alleles being expressed. Despite the few records, several cases have been documented in rodents over time. During April and May 2020, the activity of a gopher with total leucism that inhabited a niche fragmented by a residential villa and a golf course was monitored. This work presents the first known case of leucism in Cratogeomys merriami for the State of Mexico.