studied the ecology of the Snouted Treefrog (Ololygon berthae), providing new insights into sexual size dimorphism, fecundity, reproductive activity pattern, age, growth, and diet. We examined a set of 86 specimens from multiple localities from Corrientes Province, Argentina. Ololygon berthae exhibited sexual size dimorphism, with females averaging larger and heavier than males. The reproduction of O. berthae occurred during at least two periods of reproductive activity: in spring (September-October) and in summer (February-March). Gravid females contained an average of 331.1 mature ova. Based on skeletochronology, both sexes reached sexual maturity at 1 y old, while males exhibited longevity of 4 y compared to 3 y in females. Growth patterns for body size of males and females fit the von Bertalanffy's growth model well, with a tendency of females to reach a larger asymptotic size and higher growth coefficients than males, although these differences were not significant. Ololygon berthae showed a generalist diet and a sit-and-wait predation strategy. The consumption of terrestrial prey by O. berthae revealed terrestrial behavior that was unexpected for a scansorial species. Filling such knowledge gaps in the ecology of O. berthae improves the understanding of this species and could help determine if conservation actions are needed.

Se estudió la variación geográfica en la morfología craneana de Myotis riparius (Chiroptera, Vespertilionidae) a partir de 45 ejemplares que cubren prácticamente toda el área de distribución de esta especie en Argentina. Los resultados de los análisis morfométricos sugieren que las poblaciones de este murciélago en Argentina se corresponden con más de un taxón. Por un lado, las muestras referidas como M. riparius muestran una moderada uniformidad morfológica cualitativa externa y craneana, con cierta separación cuantitativa entre los animales del noroeste y Chaco y aquellos del noreste y centro-este. Por otro lado, las poblaciones del este de Corrientes, cercanas al río Uruguay, son reidentificadas como M. pampa Novaes, Wilson y Moratelli 2021, una especie recientemente descripta. Se destaca la necesidad de realizar nuevos estudios taxonómicos integrativos para avanzar con la resolución de los interrogantes planteados en este trabajo y otros previos. Con el registro de M. pampa , se eleva a 14 el número de especies del género Myotis presentes en Argentina.

An assemblage of 22 fossil woods was collected from sandstones of the Solari/Botucatu Formation, Late Jurassic-Early Cretaceous, at Paraje Tres Cerros, Corrientes Province, Argentina. The preservation of most fossils is poor. However, twelve samples have radial pitting and a few cross-fields preserved. These characters allow the assignment of fossil woods to the Araucariaceae. All the fossils seem to be of the same taxonomic unit with the following main characteristics: growth ring boundaries distinct (poorly marked), intertracheary araucarian radial pitting, uni- to biseriate bordered pits, wide tracheids, araucarioid cross-field pitting, uniseriate rays, and absence of axial parenchyma and resin canals. The fossils were assigned to cf. Agathoxylon Hartig. The size of the fossil woods and the growth ring curvatures indicate that the samples were part of big trees. The width of the growth rings also indicates significant annual growth. The taxonomic assignment suggests that monospecific forests of Araucariaceae developed in the area. This is the record of the first Mesozoic fossil remains from the Corrientes Province.

Homonota taragui is an endemic gecko of the northeast of Argentina. We estimate demographic parameters: number of individuals by populations, sex and ontogenetic stage; sexual dimorphism; survival of this species; and describe the use of microhabitat and movement patterns. We measured 11 morphological variables, determined the sex and marked individually. We found bigger head width in males. Some factors contribute to the vulnerability of this species such as its constrained geographical distribution, use of the specific microhabitat and the isolation of their populations. We highlight demography studies as an essential data source for management and conservation of critically endangered species.

Isolated rocky outcrops represent biodiversity centers, refuges for endangered species, and favorable scenarios for endemism. Most studies in these ecosystems have been focused mainly on their flora and secondarily on different groups of animals. To highlight the value of rocky outcrops as ecosystems for biodiversity conservation, in the present study, we describe the diversity of herptiles of three isolated rocky outcrops of northeastern Argentina and compare it with that of other natural areas of the region. We conducted fieldwork from September 2010 to March 2017. We calculated the alpha diversity and the number of rare, threatened and endemic species. For comparative diversity analysis, we calculated the importance of each area for amphibians and reptiles and the beta diversity. Were recorded a total of 56 species (23 amphibians and 33 reptiles), representing 35% of the herptiles recorded for Corrientes province. These species included 19 rare species, seven threatened species, and two endemic species. The overall beta diversity showed considerably differences in species composition between the compared areas. The rocky outcrops showed higher importance for amphibians and reptiles than the other areas studied. Our study contributes to the knowledge of rocky outcrops and highlights their importance in biodiversity conservation.

Introduction: Rocky outcrops influence both micro and macro habitat for plants and animals by increasing the availability and predictability of food, providing shelter, and unique microclimatic conditions. Objective: We describe the bat assemblage in three isolated rocky outcrops and their surrounding pediments, adding new data about trophic guilds and roosts. Methods: We surveyed the bat fauna of Paraje Tres Cerros, Corrientes Province, Argentina, exploring 13 sites during 26 field trips, using mist nets and search of roosts. We made an accumulation species curve and calculate inventory completeness. The similarity and composition of different habitats was compared by a Non-Metric Multidimensional Scaling (NMDS) and an ANOSIM test. Results: We reported 13 species, with a completeness inventory of the 80 % (Jacknife1), corresponding to the families Vespertilionidae, Molossidae and Phyllostomidae. The insectivorous bats were the best represented guild. We found nine types of roost for eight species in different sites. The analysis expressed low differences in the species composition between both types of habitats in the area. Conclusions: The rocky outcrops and their pediments are important ecosystems for the conservation and diversity of the bats in the region, since their assemblages are regionally unique.

We provide an updated checklist of birds of a unique landscape in northeastern Argentina, which is characterized by three isolated, rocky outcrops and their surrounding agroecosystem. We recorded 188 bird species, including nine that are globally or nationally threatened. We highlight the presence of several grassland-specialist birds of conservation concern. Of the species recorded, 80.6% are residents and 17.7% are migrants. The heterogeneity of the landscape and its structural complexity accounts the existence of a high avian species diversity, which includes both generalists and specialists. This study confirms the conservation value of this ecosystem, due both to the rocky outcrops and grassland matrix. Grasslands are one of the most threatened biomes in the world.

Natural History (NH) is a relevant discipline of the Natural Sciences that describes organisms in their environment from accurate observation. As the mother of Western sciences, its origin dates back to Aristotle’s writings. Since then it crossed human history providing essential knowledge for humanity development. After flourishing between the 17th and 19th centuries due to the exploratory travels of European naturalists to the new continents, NH has lost appreciation in its contribution to scientific knowledge. The debate about its role in sciences has swung like a pendulum between estimation and dismissal. In this contribution, we present the main themes of this debate. We expose our point of view from our experience that revalues the history of NH under the influence of Alexander von Humboldt and Amado Bonpland´ works. The specialization of sciences, technological advances, the loss of the naturalistic sense, and the connection with romanticism have been among, the main causes that have discredited NH. However, we conclude that history shows us that NH has been and is fundamental for the growth and development of humanity.

La Historia Natural (HN) es una disciplina relevante de las Ciencias Naturales que se encarga de describir a los seres vivos y su ambiente a partir de la observación precisa. Como madre de las ciencias occidentales, sus orígenes se remontan a los escritos de Aristóteles, para atravesar desde entonces la historia de la humanidad brindando conocimientos esenciales para su desarrollo. Luego de su auge entre los siglos XVII y XIX con los viajes exploratorios de los naturalistas europeos a los nuevos continentes, la HN ha perdido valoración en el aporte a la construcción del conocimiento científico. Desde entonces el debate sobre el rol de la HN en las ciencias ha oscilado como un péndulo entre su estimación y desestimación. En esta contribución, presentamos los principales temas de este debate aportando nuestro punto de vista a partir de nuestra experiencia en la revaloración de la historia de la HN, resignificada con la influencia de la obra de Alexander von Humboldt y Amado Bonpland. La especialización de las ciencias, los avances tecnológicos, la pérdida del sentido naturalista y la vinculación con el romanticismo han sido, entre otras, las principales causas que han desacreditado a la HN. Sin embargo, concluimos que la historia nos muestra que la HN ha sido y es fundamental para el crecimiento y desarrollo de la humanidad.

We described the karyotypes of five snake taxa from Argentina: Erythrolamprus almadensis, E. ceii, E. poecilogyrus caesius, E. p. schotti and E. p. sublineatus, and also intergrading individuals between the last two subspecies by conventional staining, chromosome bandings and fluorescent in situ hybridization (FISH) with 28S ribosomal DNA probes. Erythrolamprus ceii and E. almadensis share a diploid chromosome number of 2n= 28, whereas in E. poecilogyrus intraspecific variations were observed: E. p. caesius has 2n= 28, E. p. schotti and E. p. sublineatus as well as in the intergrading individuals have 2n= 32. In E. almadensis and E. p. caesius, the 2nd and 6th chromosome pairs respectively are heteromorphic by size, morphology and C-banding pattern. These results allow us to suggest that these chromosome pairs might be considered as the ZW sex chromosomes in these species. The present comparative cytogenetic analyzes contributes to the already remarkable karyotypic variability in Erythrolamprus genus and propose a hypothesis about potential mechanisms involved in the chromosome evolution among taxa analyzed. Furthermore, the karyotypic differences observed between E. p. caesius (2n= 28) and E. p. schotti and E. p. sublineatus (2n= 32) might play a causal role in speciation.

The karyotypes of four Xenodontini snake species, Lygophis dilepis, L. meridionalis, L. flavifrenatus and L. anomalus, are here described for the first time. We studied specimens from northeastern Argentina using conventional and silver (Ag-NOR) staining. While the typical ophidian karyotype is 2n = 36, we found that the karyotype of the studied species is 2n = 34, with metacentric and submetacentric chromosome pairs. The 4th NOR staining revealed that nucleolar organizer regions (NORs) are located on one pair of microchromosomes. In L. dilepis and L. anomalus the 4th chromosome pair is heteromorphic, and we suggest that it might be considered as the ZW sex chromosome pair. The optimization of available karyological data on a molecular phylogenetic tree of the tribe Xenodontini shows that the diploid numbers 2n = 28, 30 and 34 represent putative synapomorphy for Erythrolamprus, Xenodon and Lygophis, respectively. Our results provide new insights which fill gaps in our knowledge on the cytology in the genus Lygophis and identified a possible diagnostic character for the genus.

Background: a series of events take place in a precise spatial and temporal context during the development of any organism. Typically, certain ontogenetic processes are consistent with the proper completion of previous events. Objective: to identify possible heterochronic events that may relate to altricial and precocious development patterns. Methods: we analyzed the ontogeny of three species of birds with two different development models: Columba livia (semialtricial 2), Coturnix coturnix, and Gallus gallus domesticus (precocial 2). The starts and endings of thirteen morphological events were compared, from hour 16 of incubation to the time of hatching. Results: while no differences in the sequence of developmental events were found, the events of the maturation stage in the altricial kind started earlier compared to the precocial species. Ontogenetic acceleration events in C. livia and C. coturnix explain how these species reach a level of morphological development similar to that of G. gallus domesticus, but with shorter incubation period. Conclusion: the results provide information not considered in the literature of the specialty about heterochronic events in early developmental stages of poultry.

Con el objetivo de aportar informacion sobre la variacion de los caracteres osteologicos en el genero Liolaemus, examinamos siete individuos de Liolaemus azarae tratados con la tecnica de diafanizacion y tincion diferencial de cartilago y hueso. Describimos el estado de quince caracteres craneales y comparamos ocho elementos oseos con dos especies del grupo wiegmanni: L. occipitalis y L. lutzae. Liolaemus azarae se distingue de estas ultimas por siete caracteres.

Fil: Gonzalez Marin, Maria Andrea. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Nacional Patagonico; Argentina

Fil: Cajade, Rodrigo. Universidad Nacional del Nordeste. Facultad de Cs.exactas Naturales y Agrimensura. Departamento de Biologia. Laboratorio de Herpetologia; Argentina. Alianza para la Conservacion del Patrimonio Natural y Cultural del Paraje Tres Cerros; Argentina

Luego de la elaboración de la primera lista roja de la herpetofauna de la República Argentina, realizada en el año 2000, son numerosos los cambios y estudios efectuados en los diferentesgrupos de saurios de la Argentina. Si bien hay avances realizados en todas las ramas de la biología relacionadas a las lagartijas, los progresos taxonómicos y ecológicos son los más evidentes. Debido a estos progresos, y a la implementación de sustanciales modificaciones conrespecto a la metodología que se utilizara en el año 2000, un grupo de veintisiete especialistas de diferentes instituciones académicas de la Argentina aportaron información biológica, ecológica, geográfica y taxonómica en un taller que permitió reevaluar el estado de conservación de las 256 especies de lagartijas y anfisbenas de la Argentina. Los resultados obtenidos indicanque setenta y ocho especies se encuentran incluidas en la lista roja (una En Peligro, nueve Amenazadas y 68 Vulnerables), 31 Insuficientemente Conocidas y 147 No Amenazadas. Con respecto a la categorización anterior de la AHA, se agregaron 94 especies, de las cuales 87 son nuevos taxa, cuatro revalidadas, y otras tres especies fueron incorporadas a la fauna argentina. Asimismo cinco especies fueron extraídas del listado de la fauna de la República Argentina. En comparación con los resultados obtenidas en la categorización del año 2000, observamos que el número de especies Amenazadas se incrementó de cinco a nueve especies y de siete a 68 especies como Vulnerable, incluyendo a los géneros Phymaturus y Anisolepis. Asimismo, se categorizó como Insuficientemente Conocida a 31 especies contra 108 del año 2000. Estos resultados son en parte debido al incremento en el conocimiento sistemático, biológico, ecológico y biogeográficos de las lagartijas y anfisbenas de la Argentina, por el cambio radical de la metodología utilizada y también por los efectos de la presión antrópica sobre las especies y/o sus habitats. After the first herpetofaunal red list for Argentina, which was published in the year 2000, there had been numerous changes and studies made on different groups of lizards from Argentina. Although there had been contributions in all areas of lizard biology, those made in taxonomy and ecology are the most evident. Due to these and the implementation of substantial modifications with respect to the methodology used in the year 2000, a group of twenty-seven specialists from different Argentinian institutions contributed biological, ecological, geographic and taxonomic information to a workshop that allowed re-evaluation of the conservation status of the 256 lizard and amphisbaenian species from Argentina. Results indicate that 78 species are included in the red list (one Endangered, nine Threatened, and 68 Vulnerable), 31 are insufficiently known and 147 Non-threatened. Compared with the previous AHA categorization, 94 new species have been added, of which 87 are new taxa, four re-validations, and three species were incorporated to the Argentina fauna; five species were deleted from the Argentina list. Compared with the 2000 yr results, threatened species increased from five to nine species, and vulnerable species increased from seven to 68, including all species of the genera Phymaturus and Anisolepis. There are 31 species considered as insufficiently known against 108 listed in this category in 2000. These results are partially based on the increase in systematic, biological, ecological and biogeographical knowledge of lizards and amphisbaenians, and by the radical change in methodology and by effects of anthropogenic pressure on species and/or their habitats.

To contribute to the knowledge of chromosome evolution in Amphisbaena, we describe the karyotype constitution and the NOR location of Amphisbaena bolivica Mertens, 1929.

The karyotype of Typhlops brongersmianus is reported on the basis of specimens from north-eastern Argentina. The conventional Giemsa staining showed that the species has 2n = 34 chromosomes, including 8 pairs of macrochromosomes and 9 pairs of microchromosomes. Ag-NOR staining revealed the NORs location on a pair of macrochromosomes. The chromosome number and karyotypic morphology are similar to those of Neotropical typhlopid previously karyotyped.

Cytogenetic analyses (Giemsa staining and NOR-banding) were performed on South American species of Amphisbaenidae. Leposternon microcephalum (2n = 34), Amphisbaena darwini heterozonata(2n = 30), A. hiata (2n = 30) and A. mertensi (2n = 40) from different localities of Argentina were examined. The comparative cytogenetic analysis indicates that the four species might be distinguished by the NORs locations.