Bernardino Rivadavia Natural Sciences Museum

The leatherback turtle (Dermochelys coriacea) undertakes extensive migrations between nesting and foraging areas, where it is exposed to threats such as fisheries bycatch, coastal development, and pollution. Although classified globally as Vulnerable by the IUCN, the Southwest Atlantic subpopulation is considered Critically Endangered, with nesting restricted to Brazil. While satellite telemetry and previous mitochondrial DNA (mtDNA) Genetic Mixed Stock Analysis (MSA) studies have indicated that leatherbacks from West African rookeries migrate to foraging grounds off Argentina and Uruguay, the potential for connectivity with rookeries from other regions remains an open question. Genetic Stock Identification (GSI) using 15 nuclear DNA (nDNA) microsatellite markers was conducted on 78 stranded or incidentally caught leatherbacks from feeding grounds off the coasts of Argentina and Uruguay. Assignment analysis results demonstrated that 92% of the foraging leatherbacks originated from Ghana and Gabon in the Southeast Atlantic (SEA), with lesser contributions from the rookeries in the Northwest Atlantic (NEA; 6%) and the Southwest Indian Ocean (SWI; 1%) rookery in South Africa, all with assignment probabilities (AP) exceeding 95%. Our findings corroborate and extend previous mtDNA studies by enhancing the precision of GSI for individuals possessing common haplotypes and by clarifying the unknown origin of individuals with 'orphan' mtDNA haplotypes, such as Dc7.1, which were assigned to the SEA rookeries (AP = 99%). Furthermore, we directly assigned one individual, previously of uncertain mtDNA origin (Dc9.1), to the South Africa rookery (AP = 97%), highlighting the need to consider the extension of the SWI Regional Management Unit (RMU) boundaries to Southwest Atlantic waters in future assessments. The absence of detected connectivity with Brazilian nesting populations underscores the necessity for increased sample sizes and the application of advanced molecular markers. These results advance the understanding of population connectivity across oceanic scales and emphasize the crucial role of international collaboration in conservation endeavors.

Methane seepage at the seafloor can form gas hydrate and sustain chemosynthetic communities of deep-sea animals. Most known hydrate seeps occur shallower than 2000 m on continental slopes, whereas hydrothermal vents are found at greater depths along active spreading centres. Here we report the discovery of hydrate mounds with cold-seep fauna at 3640 m deep on the Molloy Ridge. The mounds display seafloor morphologies resulting from progressive stages of hydrate dissociation. Gas bubbles from the mounds rise to within 300 m of the ocean surface, and isotopic analysis shows the hydrates contain thermogenic gas. Crude oil sampled from the hydrate deposits indicates a young Miocene source rock formed in a fresh-brackish water paleo-environment. The hydrate mounds are inhabited by taxa including siboglinid and maldanid tubeworms, skeneid and rissoid snails, and melitid amphipods. Family-level composition of the fauna is similar to that of Arctic hydrothermal vents at similar depths, including the Jøtul vent field on the Knipovich Ridge, and less similar to nearby methane seeps at shallower depths. The overlap between seep and vent fauna in the Arctic has implications for understanding ecological connectivity across deep-sea habitats and assessing their vulnerability to future impacts from seafloor resource extraction in the region.

The oldest known pterosaurs lived approximately 220 million years ago1 and were already animals capable of powered flight,2 an ability that later evolved independently among paravian dinosaurs, the group that includes living birds and their closest non-avian relatives.3 Flight is a complex locomotory mode that requires physiological adaptations4 and a dramatic transformation of the body plan, including changes in body proportions, specialized integument, and acquisition of novel neurosensory capabilities.5 Although pterosaurs and birds developed distinct skeletal and integumentary adaptations for flight, they are hypothesized to share neuroanatomical traits linked to aerial locomotion.6,7,8,9 Here, we use geometric morphometrics and phylogenetically informed analyses to assess the origin and evolution of brain shape and size in pterosaurs, tracing the transformation from their non-volant closest relatives (lagerpetids), and compare their trajectory with that in the dinosaur-bird transition. Pterosaurs have globular brains with moderately enlarged hemispheres, more closely resembling non-avian paravians such as troodontids and Archaeopteryx lithographica than living birds. Whereas birds inherited their basic brain structure from their dinosaurian ancestors,10,11,12,13,14,15,16,17 pterosaurs share only the ventrolateralization of the optic lobe with their closest non-volant relatives, the lagerpetids. This suggests that, in contrast to the bird-line archosaurs, where exaptation may have played a central role in the stepwise assembly of the avian brain configuration, brain evolution in pterosaurs seems to have unfolded rapidly at the origin of flight.

Se efectúa un análisis etnobotánico de las informaciones folklóricas registradas en la Encuesta Nacional del Folklore durante 1921 de Santiago del Estero, para luego describir y discutir en detalle las indicaciones terapéuticas de las principales subcategorías de uso medicinal de las plantas. Un total de 13.241 fojas digitalizadas de la encuesta fueron consultadas on-line de la plataforma virtual del Instituto Nacional de Antropología y Pensamiento Latinoamericano. Las informaciones sobre folklore botánico se convirtieron en datos etnobotánicos tanto a partir del análisis exhaustivo de las correspondencias botánico-fitonímicas de los nombres vernáculos de las plantas, como de aquellas obtenidas entre las expresiones folklóricas conque fueron referidas sus indicaciones medicinales y las categorías biomédicas correspondientes. Se identificaron 2619 datos etnobotánicos totales de 335 taxa vegetales, de los cuales 1795 corresponden a usos medicinales de 283 taxa. Las principales subcategorías de uso medicinal agrupan 980 datos etnobotánicos acerca de 229 taxa de Spermatophyta, 3 de Pteridophyta y 3 del reino Fungi. Entre ellos, 296 datos fueron referidos contra trastornos del sistema digestivo, 182 como vulnerarios, 156 como antitérmicos, 120 contra trastornos del sistema nervioso, 118 del sistema respiratorio y 115 datos contra trastornos dermatológicos. Casi el 70% de ellos corresponden a plantas nativas o asilvestradas, aunque el 50% de las diez plantas con mayor número de indicaciones terapéuticas corresponden a especies exóticas. Se evidenciaron diferencias sustanciales respecto a la participación proporcional de la mayoría de las subcategorías de uso medicinal respecto a lo hallado en estudios actuales para el mismo complejo biocultural. Estos resultados indican una máxima preponderancia de los datos registrados para Santiago del Estero dentro de la E.N.F. de 1921 a nivel nacional, así como la mayor fuente de datos etnobotánicos hallada hasta el presente para dicha provincia y para el Chaco argentino en general.

Several studies analyzed the origin of flapping birds, but only a few of them explored the scapular girdle myology in early birds and non-avian paravians. We analyze the pectoral girdle morphology in different groups of non-ornithothoracine paravians with the aim to hypothesize the anchorage sites of selected pectoral muscles and determine their main functions in forelimb movements. Notably, the pectoral girdle remained morphologically stable among non-ornithothoracine paravians since certain aspects of the coracoid and scapula are similar in non-flying taxa, such as the cursorial Buitreraptor, as well as those with the ability to fly, such as the four-winged Microraptor, the long-tailed Archaeopteryx and the pygostylians Confuciusornis and Sapeornis. The distinctions among these taxa are slightly discernible in bone morphology, but they are obvious in the forelimbs feather coverage. In this sense, main pectoral muscles (i.e., mm. supracoracoideus, pectoralis and deltoideus scapularis/major) had similar origin and insertion places, and their inferred functions were similar across a wide array of body shapes of early paravians. The most significant muscular changes occurred in the common ancestor of Pygostylia, and consisted in the displacement of the origin of the mm. biceps brachii and coracobrachialis p. cranialis, accompanying the greater development of the acrocoracoid process and the loss of the subglenoid fossa. These modifications allowed more muscles to participate in humeral protraction and in the maintenance of wing extension. Subsequently, in the Ornithothoraces node, coracoid transformations contributed to the medial reorientation of the supracoracoidal canal thus allowing the m. supracoracoideus to fulfill a wing elevation function. Our study suggests that in non-ornithothoracine paravians, the main movements of the forelimb (either fliers or not) were predominantly craniodorsal to caudoventral. The humeral movements were performed in a similar manner, in which the main elevators were the mm. deltoideus and latissimus dorsi group, while the mm. supracoracoideus and pectoralis would have acted as protractor and depressor, respectively. Therefore, the ability to maintain a continuous flapping flight present in extant volant birds may have been acquired at the Ornithothoraces node, while Archaeopterygidae, Confuciusornithidae and Omnivoropterygidae may have had functional flight, short in duration and space displacement.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12862-025-02454-z.