Damselflies (Coenagrionidae) have been avoiding leaf veins during oviposition for at least 52 million years

Plant-insect interactions can provide extremely valuable information for reconstructing the oviposition behavior. We have studied about 1350 endophytic egg traces of coenagrionid damselflies (Odonata: Zygoptera) from the Eocene, identifying triangular or drop-shaped scars associated with them. This study aims to determine the origin of these scars. Our behavioral study of about 1,800 endophytic eggs from recent coenagrionids indicates that these scars were caused by ovipositor incisions, but without egg insertion. The scar correlates (χ2-test) with leaf veins in both fossil and extant species. We infer that a female would detect the proximity of a leaf vein and avoid egg-laying, generating a scar that also fossilizes. For the first time, a scar produced by the ovipositor has been identified, indicating the existence of undesirable areas for oviposition. Accordingly, we recognize that Coenagrionidae damselflies (narrow-winged damselflies or pond damselflies) have been avoiding leaf veins for at least 52 million years

Differential influences of allometry, phylogeny and environment on the rostral shape diversity of extinct South American notoungulates

Understanding the mechanisms responsible for phenotypic diversification, and the associated underlying constraints and ecological factors represents a central issue in evolutionary biology. Mammals present a wide variety of sizes and shapes, and are characterized by a high number of morphological convergences that are hypothesized to reflect similar environmental pressures. Extinct South American notoungulates evolved in isolation from northern mammalian faunas in highly disparate environments. They present a wide array of skeletal phenotypes and convergences, such as ever-growing dentition. Here, we focused on the origins of the rostral diversity of notoungulates by quantifying the shape of 26 genera using three-dimensional geometric morphometric analysis. We tested the influence of allometry and phylogeny on rostral shape and evaluated rates of evolutionary change in the different clades. We found strong allometric and phylogenetic signals concerning the rostral shape of notoungulates. Despite convergent forms, we observed a diffuse diversification of rostral shape, with no significant evidence of influence by large-scaled environmental variation. This contrasts with the increase in dental crown height that occurred in four late-diverging families in response to similar environmental pressures. These results illustrate the importance of considering both biological components and evolutionary rates to better understand some aspects of phenotypic diversity.Fil: Gomes Rodrigues, Helder. Muséum National d'Histoire Naturelle; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cornette, Raphaël. Centre National de la Recherche Scientifique; Francia. Muséum National d'Histoire Naturelle; FranciaFil: Clavel, Julien. Ecole Normale Supérieure; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cassini, Guillermo Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; ArgentinaFil: Bhullar, Bhart-Anjan S. . University of Yale; Estados UnidosFil: Fernández-Monescillo, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Moreno, Karen. Universidad Austral de Chile. Instituto de Ciencias de la Tierra; ChileFil: Herrel, Anthony. Centre National de la Recherche Scientifique; Francia. Muséum National d'Histoire Naturelle; FranciaFil: Billet, Guillaume. Muséum National d'Histoire Naturelle; Francia. Centre National de la Recherche Scientifique; Franci

Palaeoecological implications of the sympatric distribution of two species of Machairodus (Felidae, Machairodontinae, Homotherini) in the Late Miocene of Los Valles de Fuentidueña (Segovia, Spain)

In this paper, we study a sample of cranial, mandibular and dental remains of two species of the machairodontine felid genus Machairodus from the Early Vallesian (MN 9, around 10 Ma) site of Los Valles de Fuentidueña (Segovia, Spain): the tiger-sized Machairodus aphanistus, and the smaller and more primitive M. alberdiae; a species which is only known from this site. The fossils of these two sympatric populations are compared with the most abundant samples of M. aphanistus from the Late Vallesian (MN 10), younger sites of Batallones-1 and Batallones-3 (Torrejón de Velasco, Madrid, Spain). The results support the specific separation of M. alberdiae from M. aphanistus based on several differences in teeth size and proportions. Besides this, we observed differences among the analysed samples of M. aphanistus, indicating a differentiation between the older and more primitive form from Los Valles de Fuentidueña, and the younger and more derived one from the two Batallones sites. These differences fit well with the morphological evolution of this lineage towards the more derived Turolian Amphimachairodus giganteus. Finally, a relatively structured, patched habitat, combining the presence of open landscapes with shrubby and wooded areas, is inferred to explain the sympatric distribution of these two large machairodontines in Los Valles de Fuentidueña.M F-M thanks to the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ministerio de Ciencia Tecnología e Innovación Productiva from Argentine Republic for his economic support during his PhD. MJS belongs to the Research Groups CSIC-641538 and IDL-RG2 (Coast, Water and Earth surface processes)

Supp. Tab.1 from Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

Dental measurements in Mesotheriidae and Ctenodactylida

Complete craniomandibular and dental remains of Microtypotherium choquecotense (Notoungulata, Typotheria, Mesotheriidae) from the Middle Miocene of the Bolivian Altiplano

International audienceWe report new complete craniomandibular and dental remains of the mesotheriine notoungulate Microtypotheriumchoquecotense, from the Choquecota-Hakallinca type locality, Totora Formation (middle Miocene, Bolivia). Microtypotheriumchoquecotense is the most abundant taxon in this locality, with ca. 57% of the mammalian fossil recovered (15 out of 26).We estimate for an adult individual (Museo Nacional de Historia Natural, La Paz, Bolivia, MNHN-Bol-V 13223), a body massof 21.69±3.79 or 21.26±4.88 kg, based on cranial or mandibular measurements, respectively. The studied fossils widelyimprove our knowledge of the morphology of the so-far elusive M. choquecotense, as well as other early-divergingmesotheriines with which it shares some characteristics (e.g., Altitypotherium spp.), such as I1 oval in occlusal view and withsmooth enamel, median lobe of M1-2 aligned lingually with the protoloph and metaloph, well-differentiated septum atthe incisive foramen, and parallel upper diastemata. Autapomorphic features include an oval i1 (which differentiates it from the trapezoidal shape as seen in Altitypotherium/Rusconitherium) and P4 with a marked enamel fold on the lingual edge.The presence of the latter trait is particularly striking as it has been either considered for differentiating late-divergingmesotheriines (Pseudotypotherium spp. and Mesotherium; also present in Caraguatypotherium) from earlier-diverging generaor for distinguishing species within Eutypotherium. In short, this character seems to occur much earlier in the evolutionaryhistory of mesotheriines than previously thought and it might document intraspecific variation as well, as a polymorphicfeature, within Microtypotherium and Eutypotherium

Supp. Tab. 2 from Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

Test of correlation between dental area and occlusal complexity

Recognition of a new nothrotheriid genus (Mammalia, Folivora) from the early late Miocene of Achiri (Bolivia) and the taxonomic status of the genus Xyophorus

International audienceNew remains of a relatively plesiomorphic nothrotheriid sloth have been recovered from upper Miocene-aged deposits near the village of Achiri in the Altiplano of Bolivia. The new specimens appear allied to other middle and late Miocene remains from Argentina and Bolivia that have been assigned to the pseudo-genus "Xyophorus." "Xyophorus" has not previously been recognized as a distinct genus because of the paucity of material it encompasses. The new specimens, however, include a well-preserved squamosal with attached auditory region, and an isolated astragalus. These elements, which are described in detail, provide a sufficient number of distinctive characters to place the previous fossils assigned to "Xyophorus" into a new monotypic genus. Beyond exhibiting a suite of distinctive autapomorphies which justify its formal taxonomic designation, the new taxon shares several synapomorphies with more derived members of Nothrotheriidae, but also retains a number of plesiomorphies characteristic of basal megatherioid taxa, and shows a number of intermediate features. Although the new taxon is too incomplete to justify a full phylogenetic analysis, it appears to represent a basal member of Nothrotheriidae. Resolution of the taxonomic status of the genus Xyophorus awaits a better understanding of the taxonomy of early Miocene-aged basal megatherioids

Postcranial anatomy of the extinct terrestrial sloth Simomylodon uccasamamensis (Xenarthra, Mylodontidae) from the Pliocene of the Bolivian Altiplano, and its evolutionary implications

International audienceExtinct terrestrial sloths are common elements of the late Cenozoic South American fossil record. Among them, Mylodontinae species were particularly abundant in the Americas throughout the Pleistocene epoch, and their anatomy is relatively well known. In contrast, less information is available from the Neogene record and particularly from localities at low latitudes, with an additional and considerable bias in favor of craniodental rather than postcranial remains. In this contribution, we provide comparative descriptions of several postcranial bony elements ascribed to Simomylodon uccasamamensis, a moderatesized extinct mylodontine from the Andean Altiplano. This species was particularly abundant during latest Miocene–late Pliocene times in the high altitudes of the Andean Cordillera, and so far represents the best known mylodontine from the Neogene of South America. Its anatomy is compared with that of several extinct terrestrial sloths, with the aim of using the observed morphologies to elucidate taxonomy, phylogeny, and locomotion. From a morphofunctional perspective, the postcranium of S. uccasamamensis is consistent with that of a terrestrial graviportal quadruped, with moderate climbing and digging capabilities

El yacimiento de Ayo Ayo-Viscachani (Plioceno-Pleistoceno, Departamento de La Paz, Bolivia): 50 años desde su descubrimiento

International audienceEl yacimiento boliviano de Ayo Ayo-Viscachani se sitúa en proximidad de los homónimos pueblos altiplánicos, a unos 70 kmal sur de La Paz y aproximadamente a 4.000 metros de altitud sobre el nivel del mar. El yacimiento fosilífero se distribuyea ambos lados de la Ruta Nacional 1, que conecta la capital boliviana con la ciudad de Oruro. Su contenido faunístico secompone de mamíferos principalmente pliocenos, y minoritariamente pleistocenos, que fueron dados a conocer por RobertHoffstetter y colaboradores en 1971. Recientes campañas paleontológicas permitieron aclarar la geología tanto de AyoAyo como de Viscachani, evidenciando diferencias a nivel sedimentológico entre ellas, con facies de carácter másrelacionadas con ambientes fluviales en el sector Ayo Ayo y lacustres en el sector de Viscachani. Pudimos realizar nuevosmuestreos de la toba Ayo Ayo y, por primera vez, datar el mismo nivel en las cercanías de Viscachani. Los análisisradioisotópicos (Ar/Ar) realizados en las dos tobas arrojaron una edad absoluta de 2,9+/-0,02 Ma, representando el mismoevento volcánico y permitiendo correlacionar ambos perfiles. En cuanto a contenido faunístico, los taxones pliocenos,procedentes de la Formación Umala, incluyen un ave fororrácido, los metaterios Sparassocynus heterotopicus y Microtragulusbolivianus, el litopterno Promacrauchenia sp., el notoungulado Posnanskytherium viscachanense, los roedores Praectenomysrhombidens, Prolagostomus sp., Phugatherium saavedrai y “Orthomyctera” andina, los xenartros acorazados Pampatheriumsp., Macroeuphractus cf. moreni, y los perezosos Megatherium altiplanicum y Simomylodon uccasamamensis. Entre los taxonesdel Pleistoceno inferior figuran el litopterno Macrauchenia patachonica y xenartros de gran tamaño incluyendo Glyptodonsp., Glossotherium sp., Catonyx tarijensis, y Megatherium tarijense. Además, registramos la presencia de los inmigrantesnorteamericanos Equus sp., Palaeolama sp., y un cérvido indet. Entre los megamamíferos, se destaca la preponderancia delos xenartros de gran tamaño, tanto para el Plioceno como para el Pleistoceno de la localidad de Ayo Ayo-Viscachani. Enniveles pliocenos, la ausencia de taxones norteamericanos y el último registro de algunos taxones sudamericanos sugierecierto grado de endemismo para la fauna hallada en la Formación Umala. Esto podría estar relacionado con el carácteraltiplánico de esta área que registraba durante el Plioceno tardío una altitud estimada de 2.000–3.000 metros sobre elnivel del mar. Finalmente, los roedores de Ayo Ayo-Viscachani, así como la abundancia relativa de xenartros y la escasezde notoungulados, indicarían un ambiente árido y de bajas temperaturas, también compatible con las elevadas altitudes delAltiplano a finales del Neógeno

Occurrence of Cyclusphaera scabrata in Achiri (late middle-early late Miocene?, Bolivian Altiplano): Paleogeographical implication

International audienceA palynological assemblage including the extinct araucarian dispersed pollen, Cyclusphaera scabrata, was analysed from the Achiri locality, Bolivian Altiplano. The fossil-yielding locality of Achiri is located in the Pacajes Province, La Paz Department, in the northwestern Altiplano, Bolivia. The Achiri locality is very well known by the fossil vertebrate faunas recovered from the Mauri Formation (M6). The palynological samples come from fine-grained and plant-rich lacustrine levels lower in the same unit. An age between late middle to early late Miocene? was inferred for the palynological association studied, based on local stratigraphy and radioisotopic ages obtained higher in the series. The retrieved association is mainly represented by angiosperms; although gymnosperms, bryophytes, ferns, and freshwater algae are also documented. Compositae are the most abundant group within angiosperms, and Polylepis also occurred but in low percentages. The presence of C. scabrata in the Bolivian Altiplano expands the taxon distribution outside northern South America and provides additional evidence to infer timing and distribution routes of conifers, restricted toward the tropics during the latest Neogene. Its occurrence supports a paleoelevation of no more than 2000 m for the northern area of the Altiplano in agreement with previous results. Compositae of Fenestrites type and Polylepis occur earlier in Bolivia and C. scabrata later, comparing their occurrence in miocene microfloras from low to mid-latitudes of South America