Southwestern Argentina Research Articles

Social motivations in Mapuche trafkintu: toward cosmology, recovery, and critique

This article investigates social motivations in trafkintu (exchange), a concept derived from the Mapuche (Indigenous people of southcentral Chile and southwestern Argentina: literally, people of the land). We propose five key motivations for trafkintu, reciprocity, solidarity, cosmological, recovery, and critique. While reciprocity and solidarity are commonly associated with exchanges, we argue that from a Mapuche perspective it is essential also to relate them to a cosmological motivation, something often neglected by the anthropocentric focus of western academics. The motivations of recovery and critique reject the idea that Indigenous economical concepts only explain the past by considering the contemporary context of trafkintu. Recovery and critique testify to the colonial economic onslaught and the difficulty of reproducing the motivations of reciprocity, solidarity, and cosmology within a market-driven economy. Recovery and critique motivate trafkintu as a heterodox economic institution with strategic similarities to other anti-hegemonic forces, making them potential allies.

Attraction of microarthropods to dung of invasive mammals in meadows of northwestern Patagonia

AbstractThe attractive effect of dung on coprophagous beetle communities and their role in dung degradation are well‐known phenomena. However, little research has been conducted on the recruitment capacity of this substrate for other arthropods, especially those inhabiting the soil. With the aim of beginning to recognize general patterns in these relationships, the influence of the structure and origin of dung from invasive exotic mammals on the recruitment of microarthropods was investigated in two meadows within Nahuel Huapi National Park in southwestern Argentina. Abundance, richness and diversity of microarthropod communities collected on invasive mammal dung were studied. A total of 2478 microarthropods were collected and 52 species were identified. Recruitment of microarthropods on dung of two invasive coprophagic herbivores, the rabbit, Oryctolagus cuniculus and the hare, Lepus europaeus, were compared with two invasive non‐coprophagic mammals, one herbivorous, the red deer, Cervus elaphus and one omnivorous, the wild boar, Sus scrofa. Pellets of S. scrofa showed the highest microarthropod abundance and richness while diversity was greatest on pellets of C. elaphus. Pygmephorid and oribatid mites and springtails were the most abundant. Liposcelis psocopterans and oribatid mites were more abundant on S. scrofa dung. Low similarity was observed when comparing dung of invasive mammals from different sites revealing spatial variability regarding species composition. Based on its more diverse diet, we conclude that S. scrofa dung exerts a strong influence on microarthropod communities by recruiting a greater number of individuals and species than the dung of the remaining invasive mammals.

Prediction of the Global Distribution of Arhopalus rusticus under Future Climate Change Scenarios of the CMIP6

Arhopalus rusticus is a significant forestry pest known for its destructive impact on various host plants. This species, commonly found in coniferous forests across the Northern Hemisphere, has successfully spread to regions like New Zealand, Australia, and South America. This research is based on the known distribution sites of A. rusticus. Projections are made for the potential global distribution of A. rusticus under historical climatic conditions (1970–2000) and future climatic conditions (2081–2100) for the four forcing scenarios of the Coupled Model International Comparison Program 6 (CMIP6). The aim was to analyze the effects of climate change on the distribution range of this pest and its invasion trend in the southern hemisphere, and to support relevant departments in enhancing the effectiveness of forestry pest control strategies. The study utilized the Biomod2 software package in R to compare six models: generalized linear models (GLMs), generalized additive models (GAMs), multivariate adaptive regression splines (MARSs), artificial neural networks (ANNs), classification and regression trees (CTAs), and random forests (RFs) for modeling species distributions. The optimal model was selected based on evaluation indexes such as AUC and TSS. Projections of A. rusticus distribution under historical and future climate scenarios were created. The prediction results were visualized using ArcGIS software (version 10.2) to classify fitness levels and calculate distribution areas. Based on evaluation metrics, random forests (RFs) demonstrated the highest average assessment index scores, indicating high prediction accuracy (AUC = 0.99, TSS = 0.91, Kappa = 0.93). Model predictions revealed that, under historical climatic conditions, A. rusticus was predominantly found in northern Europe, eastern Asia, eastern and southwestern coastal regions of North America, and there were also highly suitable regions in parts of the southern hemisphere, including central and southwestern Argentina, southern Australia, New Zealand, and South Africa. Among these models, each of the CMIP6’s different climate prediction scenarios had a significant impact on the predicted distribution of A. rusticus. The SSP126 scenario depicted the broadest range of suitability, while the SSP585 scenario presented the narrowest and, overall, the extent of highly suitable regions was contracting. Multi-model predictions suggested that the potential distribution area of A. rusticus during the period of 2081–2100 would likely expand compared to that of 1970–2000, ranging from an increase of 1.13% (SSP126) up to 6.61% (SSP585), positively correlating with the level of radiative forcing. Notably, the most substantial growth was observed in potentially low-suitability region, escalating from 1.17% (SSP126) to 5.55% (SSP585). The distribution of A. rusticus shows decreasing trends from coastal areas to inland areas and from high to low level suitability of regions, and further expansion into the southern hemisphere under future climate conditions. Therefore, quarantine efforts at ports of entry should be strengthened in areas that are not currently infested but are at risk of invasion, and precise preventive measures should be strengthened in areas that are at risk of further expansion under future climatic conditions to prevent its spread to inland areas.

Prediction of Suitable Habitat Distribution of Cryptosphaeria pullmanensis in the World and China under Climate Change.

Years of outbreaks of woody canker (Cryptosphaeria pullmanensis) in the United States, Iran, and China have resulted in massive economic losses to biological forests and fruit trees. However, only limited information is available on their distribution, and their habitat requirements have not been well evaluated due to a lack of research. In recent years, scientists have utilized the MaxEnt model to estimate the effect of global temperature and specific environmental conditions on species distribution. Using occurrence and high resolution ecological data, we predicted the spatiotemporal distribution of C. pullmanensis under twelve climate change scenarios by applying the MaxEnt model. We identified climatic factors, geography, soil, and land cover that shape their distribution range and determined shifts in their habitat range. Then, we measured the suitable habitat area, the ratio of change in the area of suitable habitat, the expansion and shrinkage of maps under climate change, the direction and distance of range changes from the present to the end of the twenty-first century, and the effect of environmental variables. C. pullmanensis is mostly widespread in high-suitability regions in northwestern China, the majority of Iran, Afghanistan, and Turkey, northern Chile, southwestern Argentina, and the west coast of California in the United States. Under future climatic conditions, climate changes of varied intensities favored the expansion of suitable habitats for C. pullmanensis in China. However, appropriate land areas are diminishing globally. The trend in migration is toward latitudes and elevations that are higher. The estimated area of possible suitability shifted eastward in China. The results of the present study are valuable not only for countries such as Morocco, Spain, Chile, Turkey, Kazakhstan, etc., where the infection has not yet fully spread or been established, but also for nations where the species has been discovered. Authorities should take steps to reduce greenhouse gas emissions in order to restrict the spread of C. pullmanensis. Countries with highly appropriate locations should increase their surveillance, risk assessment, and response capabilities.

Petrogenetic evolution and thermobarometry of the Late Jurassic La Hoya pluton, early stages of the North Patagonian batholith, southwestern Argentina

Petrogenetic evolution and thermobarometry of the Late Jurassic La Hoya pluton, early stages of the North Patagonian batholith, southwestern Argentina

Revision of the South American stiletto fly genera Entesia Oldroyd and Melanothereva Malloch, with the description of a new genus (Therevidae: Agapophytinae)

The South American members of the stiletto fly subfamily Agapophytinae (Diptera: Therevidae) occur in the South American Transition Zone, predominantly in Chile and southwestern Argentina. The four agapophytine genera described from this region are Entesia Oldroyd, 1968; Melanothereva Malloch 1932; Pachyrrhiza Philippi, 1865; and more recently, Sigalopella Irwin & Winterton, 2020. Here we revise Melanothereva and Entesia and describe the new monotypic genus Pachylopella. Keys to South American Agapophytinae genera and species of Melanothereva and Entesia are provided. 

A New Species of Mathevotaenia (Cestoda: Anoplocephalidae) from the Andean Tuco-Tuco, Ctenomys opimus (Rodentia: Ctenomyidae), on the Altiplano of Bolivia

A new species of Mathevotaenia Akumyan, 1946 (Cestoda: Anoplocephalidae) is described from the Andean tuco-tuco, Ctenomys opimus Wagner 1848 (Rodentia: Ctenomyidae), collected in 1984 on the Altiplano of Bolivia. This is the second species of anoplocephalid cestode recorded from rodents of the genus Ctenomys, the first being Monoecocestus torresi Olsen 1976 from the Maule tuco-tuco, Ctenomys maulinus Philippi 1872, documented in southwestern Argentina. The new species of Mathevotaenia described here has more testes per segment than any other described species of the same genus from South America. The description of a new species from a decades-old specimen highlights the need for continuous examination of museum material as well as the need for collection of new specimens from rapidly disappearing biomes around the world.

Geología, alteración hidrotermal y mineralogía del sistema de vetas Sofía-Julia-Valencia, distrito minero Andacollo, Neuquén, Argentina

The Sofía-Julia-Valencia vein system, located in the Andacollo mining district in central west Argentina, is hosted by ENE-WSW oriented strike-slip faults which are the result of reactivation of normal faults affecting Carboniferous to Jurassic rocks during Upper Cretaceous-Paleogene. These veins contain a total resource of 22,900 Oz of gold with 5.5-6.7 g/t AuEq. Geologic mapping and a U-Pb age of 71±1Ma in zircon, obtained in an altered and mineralized dacitic dyke of the district, allowed to associate the mineralizing event to the Naunauco Andesitic belt magmatism (Upper Cretaceous-Paleogene) and to the Cretaceous-Paleogene Metallogenic Belt of the Andes in southwestern Argentina. The ore bodies are made up of multiple veins and veinlets that, from oldest to youngest, correspond to: (1) scarce early quartz+pyrite+molybdenite+iron poor-sphalerite veinlets, (2) quartz+epidote+calcite±albite (apatite+rutile+titanite+light rare earth elements bearing phosphates) associated with quartz+biotite, epidote (actinolite)+chlorite+calcite, with pyrite+pyrrhotite±chalcopyrite±(iron rich-sphalerite), marcasite veins. These veins are cut and reopened by (3) polymetallic veins and veinlets formed by quartz+sericite±carbonates (chlorite), with iron-gold rich sphalerite+silver rich-galena+chalcopyrite+pyrite, native gold±arsenopyrite±(pyrrhotite, bornite, argentite). Pyrite (4) and (5) carbonate+framboidal pyrite veinlets cuts all the previous ones. Multistage carbonate generation brecciate and cut previous veins and veinlets. Quartz shows granular, comb textures and some calcites developed platy textures. Four hydrothermal alteration types affected the veins host rock: (1) patches of early potassic alteration; (2) widespread propylitic alteration with disseminated sulfides; (3) later phyllic alteration overlapped to the previous ones; and (4) late supergene alteration. The sphalerite and chlorite composition in the veins (1 and 2) along with their mineral assamblages indicates they were formed by initially alkaline fluids (e.g., feldspar stable) with intermediate sulfur and oxygen fugacity and mesothermal temperature conditions (~400-240 °C), that evolved to conditions of lower sulfur (e.g., pyrrhotite stable) and oxygen fugacity, temperature

The Body is (Not) the Land

AbstractThis article concerns the ongoing hunger and death strikes of the Mapuche, Indigenous peoples whose territories, or Wallmapu, are currently settler-occupied territories of south-central Chile and southwestern Argentina. It argues that these hunger strikes are acts of territorial precedent and corporeal autonomy that stand in opposition to the continuum of Chilean racism and its myriad devastating sociocultural and ecological effects. These hunger strikes wrest the ordering of life, and the processes and temporality of dying, from the state. In this way, the hunger strikes directly intervene in state claims to biopolitical and territorial sovereignty imposed via the settler metonymy that conflates the Mapuche body and land in order to dispossess them of a “proper” relation with land. In arguing that the Mapuche hunger strike is also an embodied and discursive precedent for territorial repossession within Mapuche kimün (knowledge), this article complicates assertions of the body as land and questions the very foundations of Chile's recursive claims to territorial sovereignty and the possibility of Mapuche territorial reclamation juridically. The Mapuche hunger strike thus should not be solely, or primarily, framed as resistance to an ongoing colonialism but rather as ongoing acts of corporeal autonomy and the establishment of body-land relationality as territorial precedence.

Taxonomy and phylogenetic analysis of the South American genus

The systematics of Philodromidae is far from complete, especially for the Neotropical genera. Among these, Petrichus Simon, 1886 is a poorly known genus restricted to arid and semi-arid environments of South America. In this work, we performed a total-evidence analysis to assess the phylogenetic relationships of Petrichus and revised the taxonomy. Petrichus is monophyletic and closer to Titanebo and the New World Ebo. Within Petrichus, two clades are obtained: the Eremean Clade, containing five species displaying a Neotropical distribution; and the Patagonian Clade, with the seven species inhabiting southern South America. Our results also support a previous hypothesis on the phylogenetic relationships within Philodromidae. Thanatini is monophyletic and includes Fageia and Berlandiella, although this is not statistically supported, whereas Philodromini emerges as paraphyletic. We propose Philodromini be expanded to contain all genera having eyes on tubercles analysed in this work plus the closely related Halodromus, whereas the circumscription of Thanatini should await future phylogenetic analyses with new evidence. As for taxonomic proposals, we synonymise Bacillocnemis Mello-Leitão, 1938 with Petrichus, Petrichus ornatus Schiapelli & Gerschman, 1942 and P. luteus (Nicolet, 1849) with P. junior (Nicolet, 1849), P. lancearius Simon, 1905 with P. tullgreni Simon, 1902; we transfer P. corticinus Mello-Leitão, 1944 to Misumenoides Pickard-Cambridge, 1900 (Thomisidae); and P. fuliginosus (Nicolet, 1849), P. cinereus Tullgren, 1901, P. sordidus Tullgren, 1901 and P. zonatus Tullgren, 1901 are regarded as nomina dubia. In total, 13 species are recognised for the genus, of which four are new (described by Griotti & Grismado): P. spira, from western Argentina, P. patagoniensis, from south-western Argentina, P. roigjunenti, from Argentina and Chile and P. eremicus, from north-central Chile. ZooBank: http://zoobank.org/References/1220255e-6431-45c2-adfe-ed58d1f89b17

Intercultural education and early childhood: strengthening knowledge based on Indigenous communities and territory

Intercultural education in Chile has focused on early childhood for more than a decade. Different measures have been implemented to strength an intercultural approach in preschools. The most outstanding has been the connection of intercultural preschools with Indigenous communities. However, these educational policies have not been accompanied by adequate resources and teacher preparation, resulting in significant shortcomings in the collaboration between Indigenous communities and preschools. To address the relevance of Mapuche (People of the Land; Indigenous inhabitants of south-central Chile and southwestern Argentina; speakers of Mapudungun) communities in intercultural preschools, this study created and implemented a pilot initiative. Using a decolonial and critical pedagogy-of-place approach, the main findings show that educators began considering Mapuche communities beyond families, discussed the role of urban Mapuche communities, and improved ethical practices to work with Indigenous communities. These findings lead me to propose recommendations in reference to policies and teacher education.

Palynostratigraphy of the Lower Cretaceous Río Mayer Formation in the Río Lista area, Austral Basin, southwestern Argentina

Palynomorph assemblages were recovered from the upper levels of the Cretaceous Río Mayer Formation in the Río Lista area, Austral Basin, southern Argentina. Thirty spore and eighteen pollen species, including one angiosperm, are identified, along with fourteen dinoflagellate cysts and six acritarch taxa. The presence of Clavatipollenites spp. and the dinoflagellate cysts Muderongia mcwhaei, Diconodinium spp., and Muderongia australis suggest an early Aptian age for these palynological assemblages. Based on the relative abundance of the major groups of palynomorphs, deposition of the Rio Mayer Formation in the Río Lista area probably occurred in a progressively shallowing marine setting, evidenced by the decrease in abundance of marine elements (dinoflagellates) and the increase of Pterospermella in upper levels of the unit. These interpretations concur with sedimentological analyses of the same stratigraphic section.

Petrology and geochronology of the San Martín de los Andes batholith: Insights into the Devonian magmatism of the North Patagonian Andes

Evidence is growing that a belt of Devonian plutonism is present in the Northern Patagonian segment of the present-day Andes. This plutonism formed along the paleo-Pacific margin of the Gondwana supercontinent. New whole rock chemistry and SHRIMP U–Pb zircon data for plutonic rocks of the San Martín de los Andes batholith (southwestern Argentina) provide insights into the magmatic and tectonic evolution of the southwestern Gondwana margin during the middle Palaeozoic. The San Martín de los Andes batholith was formed between 390 and 374 Ma and intruded into a Lower Paleozoic metamorphic basement that had been previously affected by Late Ordovician-middle Silurian deformation. Most of the batholith is composed of metaluminous, calc-alkaline tonalites and granodiorites, with subordinate volume of peraluminous garnet-bearing granites. Discrete and disperse gabbroic and dioritic rocks hosted in tonalites and granodiorites occur as either microgranular enclaves or syn-magmatic dykes. Tonalitic, granodioritic and granitic rocks develop transitional contacts among them revealing coetaneous building up throughout the plutonic suite, but when interpreting their chemical variability, they are not strictly comagmatic rocks. Collectively, field, petrographic, and geochemical data of the San Martín de los Andes batholith are interpreted to reflect concurrence of crystal fractionation, crustal assimilation and magma mixing in driving petrological diversification. Yet, gabbroic and dioritic rocks in the San Martín de los Andes batholith display geochemical characteristics of calc-alkaline primitive basalts that concur with what is being hypothesized to be a magmatic arc zone for the Devonian period. This study discusses how to interpret the evolution of the San Martín de Los Andes batholith together with other geodynamic models such as the Chaitenia magmatic arc.

Sedimentology and fossil vertebrates of the Santa Cruz Formation (early Miocene) in Lago Posadas, southwestern Patagonia, Argentina

Lago Posadas is located at the foot of the Southern Patagonian Andes, in southwestern Argentina, where the early Miocene Santa Cruz Formation (SCF) shows thick and laterally continuous exposures. This region has been scarcely explored for fossil vertebrates since the first efforts by J.B. Hatcher in 1898-99. In this contribution, we performed sedimentologic and paleontological studies in order to reconstruct depositional environments and the associated fossil vertebrate fauna. Sedimentologic data suggest that the sedimentary record begins with restricted marine-estuarine deposits grading upward to fluvial floodplains and fluvial channels. Extensive floodplains, occasionally interrupted by low-sinuosity, sand-dominated channels, show dominant reddish coloration, moderate to low paleosol development, abundant crevasse splay sandstones and lack of vegetal remains, suggesting deposition in a low gradient, oxygenated setting under elevated sedimentation rates. Vertical stratigraphic trends are subtle, suggesting little paleoenvironmental changes during deposition of the whole SCF in this region. Paleocurrent directions, sandstone composition and paleogeographic reconstructions all indicate that deposition of the SCF was strongly associated to the contemporaneous uplift of the Andes. Fossil vertebrates analyzed are the result of our collecting effort and revision of museum collections. The faunal assemblage includes 31 taxa: 28 mammals and three birds. Mammals belong to the main groups recorded in other areas of the SCF (metatherians, xenarthrans, notoungulates, litopterns, astrapotheres and rodents). The assemblage allows a Santacrucian Age sensu lato assignment for the fauna at Lago Posadas. Taxonomic revisions of several taxa are necessary to further adjust the biostratigraphic significance of this association. The combined record of arboreal, browser and frugivores, on one side, and grazer mammals and rheas, on the other, suggest the presence of both trees and open environments. Frugivores, among primary consumers, and the secondary consumers guild are under-represented due to sample and fossil remain size biases. The sedimentologic and paleontological record of the SCF in Lago Posadas suggests that the uplift of the Southern Patagonian Andes acted as a primary control on basin subsidence and sediment supply, providing a special signature for sub-andean localities. However, previously registered climatic changes are poorly recorded in this study.

Ecological and demographic impacts of a recent volcanic eruption on two endemic patagonian rodents.

Catastrophic events can significantly impact the demographic processes that shape natural populations of organisms. However, linking the outcomes of such events to specific demographic parameters is often challenging due to a lack of detailed pre-event data. The eruption of the Puyehue-Cordon Caulle volcanic complex on 4 June 2011 had profound consequences for the biota of southwestern Argentina. Our long-term behavioral, ecological, and demographic studies of two species of tuco-tucos (Ctenomys sociabilis and C. haigi) that occur in the region most heavily impacted by ash fall from the eruption provided an unusual opportunity to assess the effects of this event on natural populations of mammals. The post-eruption density of the study population for each species was markedly reduced compared to pre-eruption values, with the relative magnitude of this reduction being greater for the group-living C. sociabilis. The more extensive data set for this species indicated that ash fall from the eruption altered the food resources available to these animals; differences in pre- and post-eruption stable isotope signatures for fur samples from C. sociabilis were consistent with observed changes in vegetation. Per capita female reproductive success was also reduced in this species during the first breeding season following the eruption. Based on our detailed demographic records for C. sociabilis, neither survival of yearling females from 2010 to 2011 nor the percentage of unmarked females in the study population in 2011 differed from pre-eruption values. Instead, the post-eruption decrease in population density for C. sociabilis appeared to reflect reduced within-population recruitment of juvenile females to the 2011 breeding population. Although the eruption did not result in the local extinction of either study population, the demographic consequences detected are likely to have impacted the effective sizes of these populations, creating important opportunities to link specific demographic parameters to previously reported decreases in genetic variability detected after this significant natural event.

A combined rock-magnetic and EPR study about the effects of hydrocarbon-related diagenesis on the magnetic signature of oil shales (Vaca Muerta formation, southwestern Argentina)

A combined study of rock-magnetism and electronic-paramagnetic resonance (EPR) was performed in core samples from an oil well in the Vaca Muerta Formation (SW Argentina). The aim of this work was to characterize the effects of hydrocarbon-related diagenesis on the magnetic signature of oil shales. Similar research has been previously conducted in near-surface sediments affected by oil and gas microseepage, so as to establish a relationship between micromagnetic anomalies and the underlying reservoirs. The EPR technique was employed to measure minute concentrations of organic matter free radicals (OMFRs), Fe3+ and Mn2+. These results, and the concentrations of extractable organic matter (EOM), were compared with mass-specific magnetic susceptibility (χ) and natural remanent magnetization (NRM). The reactive OMFRs, resulting from the thermal degradation of a kerogen that yields a slightly-biodegraded crude oil, seem to have acted on the primary Fe oxides and sulfides through two diagenetic stages. The first stage might have partially dissolved these minerals. Consequently, a number of depth levels show a decrease of both χ and NRM, against an increase of the OMFRs. On the other hand, for a core-interval between 2663 and 2695 m (P18/P24), a second diagenetic stage could have produced partial replacement of framboidal pyrite by authigenic pyrrhotite, as recognized by scanning electron microscopy (SEM), electron X-ray energy dispersion (EDX) experiments and the analysis of the thermomagnetic and IRM curves. Thus, within P18/P24, magnetic parameters increase in direct proportion with the amount of OMFRs. The lithologies encompassed by P18/P24 show small levels of Mn2+, a proxy directly related to calcareous cementation. Moreover, Gamma Ray, resistivity and neutron porosity well logs reveal distinctive features for P18/P24, as well as an increase of hydrocarbon content, contrasting with the rest of the section analyzed. The hydrocarbon-induced magnetic anomalies in these oil shales seem to be conditioned mostly by their petrophysical properties.

New Patagonian baurusuchids (Crocodylomorpha; Notosuchia) from the Bajo de la Carpa Formation (Upper Cretaceous; Neuquén, Argentina): New evidences of the early sebecosuchian diversification in Gondwana

The Bajo de la Carpa Formation (Santonian) of the Neuquén basin (southwestern Argentina) has one of the most complete crocodyliform records of South America, together with the Adamantina and Marília formations of Brazil. In this contribution we report two fragmentary individuals from two different localities of the Bajo de la Carpa Formation: a middle-sized individual (MLP 26-IV-30-2), represented by postcranial remains from the Boca del Sapo locality and a large-bodied individual (MACN Pv-RN 1150), consisting only of snout elements from Paso Córdoba locality. Despite the remains of both specimens are fragmentary, they display anatomical characters of a specialized notosuchian carnivore clade: Baurusuchidae. Our phylogenetic analysis recovers these new individuals as non-baurusuchine baurusuchids, although they take multiple phylogenetic positions on the different most parsimonious trees. These new remains highlight the relevance of the Bajo de la Carpa Formation for understanding the rise of notosuchians during the Late Cretaceous.

A revision of the wolf spider genus Diapontia Keyserling, and the relationships of the subfamily Sosippinae (Araneae: Lycosidae)

The South American genus Diapontia is revised to include nine species: Diapontia uruguayensis Keyserling, 1877 ( = Diapontia senescens Mello-Leitão, 1944 syn.n.; D. infausta Mello-Leitão, 1941 syn.n.; D. pourtaleensis Mello-Leitão, 1944 syn.n.; D. albopunctata Mello-Leitão, 1941 syn.n.) from northern Paraguay, southeastern Brazil, southern Uruguay, southern to northeastern Argentina and southern Chile; D. niveovittata Mello-Leitão, 1945 from southern Paraguay, north-central Argentina and southern Brazil; D. anfibia (Zapfe-Mann, 1979) comb.n. ( = Lycosa artigasi Casanueva, 1980 syn.n.) from central and southern Chile and southwestern Argentina, transferred from Pardosa C.L. Koch, 1847; D. securifera (Tullgren, 1905) comb.n. from northern Chile and northwestern Argentina, transferred from Orinocosa Chamberlin, 1916; D. arapensis (Strand, 1908) comb.n., from Peru, transferred from Hippasella Mello-Leitão, 1944; D. calama sp.n. from northern Chile; D. songotal sp.n. from southern Bolivia; D. chamberlini sp.n. from central and southern Peru; and D. oxapampa sp.n. from northern Peru. The sister-group relationship between Diapontia and Hippasella, and their placement in the subfamily Sosippinae, were supported by phylogenetic analyses based on four molecular markers (28S, 12S, NADH1 and COI), using Bayesian inference and maximum-likelihood. We tested whether DNA barcoding techniques were able to corroborate the identity of four Diapontia species. Diapontia securifera and D. anfibia were successfully identified using COI; however, D. niveovittata and D. uruguayensis were found to share identical haplotypes and thus could not be discriminated.

Large and Mainly Unnoticed: The First Lower Tithonian Record of a Suspension-Feeding Pachycormid from Southern Gondwana

Abstract. A large fossil specimen could easily go unnoticed, especially when the specimen osteology is not well known, is usually represented by fragmentary material and has a sparsely ossified skeleton resulting in low preservation potential. This is particularly true for the suspensionfeeding Pachycormiformes, a clade of actinopterygians. This work provides the description of a complete gill raker recovered from the Upper Jurassic (lower Tithonian) levels of the Vaca Muerta Formation at Cerro Lotena, Neuquen Province, southwestern Argentina. The specimen is referred to the suspension-feeding pachycormid, Leedsichthys, based on similarities in size and shape morphology of the gill raker stalk, the shape of the gill raker base and for having similar morphology of the fimbriae (growing tongue-like distally). Although suspension-feeding pachycormids are known mainly from Laurasia, some remains were also recovered from Gondwana. The lower Tithonian Leedsichthys record extends the geographic and stratigraphic...

A new Late Jurassic halecomorph fish from the marine Vaca Muerta Formation, Argentina, southwestern Gondwana

Abstract. The knowledge of Mesozoic fish faunas of the Southern Hemisphere is still inadequate; the diversity and evolution of the Late Jurassic marine ichthyofaunas of Argentina remain unclear. One fish recovered from the Tithonian levels of the Los Catutos Member of the Vaca Muerta Formation, southwestern Argentina was considered a "caturid-like" halecomorph for almost 30 years. Recently, it was proposed that it could belong to the Pachycormiformes. A thorough comparative anatomical study of the material is conducted to test whether it could be included in †Caturidae or †Pachycormidae. The specimen is assigned to †Caturidae as a new genus and species: †Catutoichthys olsacheri (http://zoobank.org/urn:lsid:zoobank.org:act:6884876C-075C-433B-90B7-74187FC04C26, registered on 1 June 2016). The new taxon is based on a unique character combination, three of which are exclusive to †Catutoichthys olsacheri among caturids–diplospondylous vertebral column with triangular basidorsals and well-developed and fan-shaped basiventrals; neural and haemal spines strongly inclined to the body axis at an angle of 14°; a large number of infrahaemals; rounded amioid-type scales with an unornamented free field. The new taxon provides anatomical information useful for further understanding the anatomy and evolution of caturid fishes.