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Osteology of the sauropodomorph dinosaur Jaklapallisaurus asymmetricus from the Late Triassic of central India.

The Gondwana formations exposed in the Pranhita-Godavari Valley of central India include Middle Triassic to Lower Jurassic continental deposits that provide essential information about the tetrapod assemblages of that time, documenting some of the oldest known dinosaurs and the first faunas numerically dominated by this group. The Upper Maleri Formation of the Pranhita-Godavari Basin preserves an early-middle Norian dinosaur assemblage that provides information about the early evolutionary history of this group in central-south Gondwana. This assemblage comprises sauropodomorph dinosaurs and an herrerasaurian, including two nominal species. Here, we describe in detail the anatomy of one of those early dinosaurs, the bagualosaurian sauropodomorph Jaklapallisaurus asymmetricus. The new anatomical information is used to investigate the position of the species in an updated quantitative phylogenetic analysis focused on early sauropodomorphs. The analysis recovered Jaklapallisaurus asymmetricus as a member of Unaysauridae, at the base of Plateosauria, together with Macrocollum itaquii and Unaysaurus tolentinoi from the early Norian of southern Brazil. This phylogenetic result indicates that the dispersal of early plateosaurian sauropodomorphs between the Southern Hemisphere and what nowadays is Europe would have occurred shortly after Ischigualastian times because of the extension of their ghost lineage. Thus, the presence of early plateosaurians in the early Norian of South America and India reduces a previously inferred diachrony between the biogeographic dispersals of theropods and sauropodomorphs during post-Ischigualastian times.

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A Maastrichtian insect assemblage from Patagonia sheds light on arthropod diversity previous to the K/Pg event

Insect faunas from the latest Cretaceous are poorly known worldwide. Particularly, in the Southern Hemisphere, there is a gap regarding insect assemblages in the Campanian-Maastrichtian interval. Here we present an insect assemblage from the Maastrichtian Chorrillo Formation, southern Argentina, represented by well-preserved and non-deformed, chitinous microscopic remains including head capsules, wings and scales. Identified clades include Chironomidae dipterans, Coelolepida lepidopterans, and Ephemeroptera. The assemblage taxonomically resembles those of Cenozoic age, rather than other Mesozoic assemblages, in being composed by diverse chironomids and lepidopterans. To the best of our knowledge, present discovery constitutes the first insect body fossils for the Maastrichtian in the Southern Hemisphere, thus filling the gap between well-known Early Cretaceous entomofaunas and those of Paleogene age. The presented evidence shows that modern clades of chironomids were already dominant and diversified by the end of the Cretaceous, in concert with the parallel radiation of aquatic angiosperms which became dominant in freshwater habitats. This exceptional finding encourages the active search of microscopic remains of fossil arthropods in other geological units, which could provide a unique way of enhancing our knowledge on the past diversity of the clade.

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Diversity and biological traits of bees visiting flowers of Cucurbita maxima var. zapallito differ between biodiversity-based and conventional management practices.

Low diversity of pollinators and the modified composition of functional groups of bees have been proposed as the causes of pollination deficiency in cultivated Cucurbitaceae species. Functional groups of bees are determined by traits, such as body size, nesting site, and social behavior. The presence of bees with specific traits can be differentially affected by agricultural management practices. This work aimed to assess how management types (agroecological and conventional) in Cucurbita maxima var. zapallito crops affect the abundance of bees with different biological traits. The study was conducted on four farms located in horticultural areas of central-eastern Santa Fe province, Argentina. A total of 108 10-min censuses were conducted to record bee species abundance in flowers. The species were assigned to categories for each of the three biological traits. A total of 552 individuals, belonging to 16 bee species, were recorded. Honey bees were more abundant under conventional management, whereas the native bees Eucera fervens and other species were more abundant under agroecological management. Species of the categories analyzed (body size: small, medium, and large; nesting site: above-ground cavities or ground-nesting; and social behavior: solitary or social) were present on farms under both management types. We found that management type affected bees, and their effects differed among bees with specific biological traits. Medium-sized and small bees, ground-nesting bees, and solitary bees were found in greater abundance on agroecological farms than on conventional farms. Our data allowed us to explain the diversity and abundance of bees relative to the management type and biological traits of the species. Implications for insect conservation: This study suggests that incorporating biodiversity-based management strategies might increase abundance and richness of native bees with different biological traits, ensuring the free pollination service they provide and a taxonomically and functionally diverse assemblage.

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Diversifying agroecological systems: Plant-pollinator network organisation and landscape heterogeneity matter

Agroecology is a process-based agriculture that implements agrobiodiversification to stabilize ecosystem processes and crop yield, leading to sustainable food systems. Traditionally, agrobiodiversification focused on increasing within-farm plant richness, which may increase local species richness of higher trophic levels. However, it is increasingly recognized that stabilizing ecosystem processes involving plant-animal interactions –e.g., pollination- requires practices that consider the organisation of interactions and heterogeneity effects at landscape level. In this work, we investigated how plant-pollinator interactions organised in agricultural landscapes harbouring agroecological farms and how landscape heterogeneity modulated interactions organisation. We characterized the organisation of 36 plant-pollinator networks describing interactions in nine agricultural landscapes -i.e., agroecological farms and their surroundings- across four flowering peak periods in the Agri-food region of central Córdoba, Argentina. We evaluated (1) centrality to network organisation of plant and pollinator only registered interacting in agroecological farms, farm surroundings (unique species) or in both locations (shared species); and (2) network organisation across gradients of landscape configurational (mean edge density) and compositional (forest proportion) heterogeneity. We found that plant-pollinator networks at landscape scale showed nested structures. Shared plant and pollinator species were the less represented in such networks but were central to networks organisation, i.e., they were connected to most species and with the highest frequency. Results also showed that network organisation changed with landscape configurational heterogeneity. Higher landscape mean edge density was associated with higher total and unique plant richness in networks and lower richness of shared plants. Network connectance and nestedness decreased with higher landscape mean edge density, i.e., plant and pollinator species interacted with less species, shared less interaction partners with more specialist species and showed lower interaction frequency with generalist partners in more heterogeneous landscapes. Our study showed that in agricultural landscapes harbouring agroecological farms (1) a few species inhabiting and showing interactions in both agroecological farms and their surroundings are key to the organisation of plant-pollinator interactions, and (2) landscape heterogeneity modulates such organisation. As interaction networks dynamic is influenced by network organisation, landscape configurational heterogeneity may modulate the stability of the pollination process and ultimately agroecological production. Thus, the agrobiodiversification of agroecological systems may benefit from considering the complexity of plant-pollinator interdependencies across agricultural landscapes and the effects of landscape heterogeneity on such complexity.

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Habitat loss and distribution of the Ornate Horned Frog (Ceratophrys ornata): implications for its conservation in South American temperate grasslands

Ceratophrys ornata is an iconic and regionally threatened amphibian of the temperate grasslands from Argentina, Brazil, and Uruguay. Conservation assessments suggested that habitat loss is the main threat to the species, although no studies have yet explored the link between grassland replacement and C. ornata decline. Using a robust database with ∼1000 records from herpetological collections, citizen science, and long-term monitoring, we modeled the species' ecological niche to produce a map of suitable areas, where we searched for C. ornata using active and passive techniques. After exhaustive efforts, we failed to obtain recent records from Brazil and Uruguay. We also conducted Generalized Linear Models to explore the relationship between land use/cover, landscape configuration, and current species occurrence. Overall, results showed that C. ornata occurrence is negatively associated with variables related to native grasslands fragmentation and replacement (i.e., Distance to the Nearest Patch, Forest Plantations), suggesting that habitat loss may have driven local extinctions and population declines of the species. Finally, we outline the regional and national conservation needs of C. ornata and recommend focusing on in-situ conservation strategies for the Argentinean populations to ensure the species' viability.

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Mitochondrial and nuclear gene sequencing confirms the presence of the invasive sea anemone Diadumene lineata (Verrill, 1869) (Cnidaria: Actiniaria) in Argentina.

Diadumene lineata is one of the most widespread sea anemone species worldwide. Although this species has been reported a few times on the Argentine coast since 2004, its identification has traditionally been based on external morphological characteristics, and in most cases no voucher specimens are available to support previous records. In this study, we obtained DNA sequences of two mitochondrial markers (12S and 16S) and two nuclear markers (18S and 28S) from specimens of D. lineata collected in two locations on the Argentine coast separated by almost 800 km. Additionally, we conducted an analysis of the morphology, as well as the types and size ranges of cnidae, using specimens collected at three different locations along the Argentine coast. Furthermore, since introduced populations of D. lineata are presumably ephemeral and only reproduce asexually outside their native range, we examined the internal anatomy of representatives from the Argentine coast for gametogenic tissue as an indication of whether they might be capable of sexual reproduction. DNA data support our morphological identification, including cnidae analyses, of the specimens as D. lineata. Furthermore, all specimens examined were determined to be sterile. Genetic sequence comparisons, phylogenetic reconstruction, and cnidae data support the identification of individuals of D. lineata from Mar Chiquita and Garipe Beach, confirming the presence of the species on the Argentine coast using both morphological and molecular tools. The absence of fertile specimens suggests that each sampled population is likely reproducing only by asexual reproduction and possibly composed of clones. The presence of an additional category of longer p-mastigophores B2a in the actinopharynx and filaments, as well as holotrichs in the column, is also reported. For the first time, we have confirmed the presence of D. lineata in Argentina through molecular data. Additionally, our findings indicate that the analyzed specimens are sterile, suggesting that this species is not engaging in sexual reproduction in the studied localities. It is crucial to continue monitoring the populations of D. lineata along the Argentine coast to assess whether they establish sexual reproduction, expand their distribution range or disappear, or potentially cause any harm to local species or alterations in benthic communities.

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