High resolution δ18O seasonality record in a French Eemian tufa stromatolite (Caours, Somme Basin)

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Unusually thick dinosaur eggshell fragments from the Spanish Late Cretaceous

[EN] Fieldwork carried out recently in the southeastern branch of the Iberian Range (Valencia Province, Spain) has led to the collection of a large volume of dinosaur eggshell fragments of unusual thickness. These specimens, up to 4.9 mm thick, were recovered from palustrine grey marls of the upper Campanian-lower Maastrichtian Sierra Perenchiza Formation, which comprises a wetland paleoenvironment deposit. These eggshell fragments have a characteristic compactituberculate ornamentation, dinosauroid-spherulitic organisation, and exhibit a complex canaliculate respiratory system. The external tuberculate surface of the shell as well as the internal microstructure enable referral to Megaloolithus aff. siruguei, the most common megaloolithid oospecies known from the Iberian Peninsula and southern France. The biostratigraphic range of M. siruguei matches the temporal distribution of titanosaurid dinosaurs across the Iberian Range, tentatively considered to be potential producers.This work was supported by the Ministerio de Economia y Competitividad of Spain [Secretaria de Estado de Investigacion, Desarrollo e Innovacion, projects CGL2013-47521-P and CGL2014-53548-P]Company Rodríguez, J. (2017). Unusually thick dinosaur eggshell fragments from the Spanish Late Cretaceous. Historical Biology (Online). 31(2):203-210. https://doi.org/10.1080/08912963.2017.1357717S203210312Allain, R., & Suberbiola, X. P. (2003). Dinosaurs of France. Comptes Rendus Palevol, 2(1), 27-44. doi:10.1016/s1631-0683(03)00002-2Bravo, A. M., & Gaete, R. (2014). Titanosaur eggshells from the Tremp Formation (Upper Cretaceous, Southern Pyrenees, Spain). Historical Biology, 27(8), 1079-1089. doi:10.1080/08912963.2014.934231Canudo, J. 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Vertebrados continentales del Cretácico superior (Campaniense-Maastrichtiense) de Valencia [PhD dissertation]. Valencia: Universidad de Valencia.Company, J., & Szentesi, Z. (2012). Amphibians from the Late Cretaceous Sierra Perenchiza Formation of the Chera Basin, Valencia Province, Spain. Cretaceous Research, 37, 240-245. doi:10.1016/j.cretres.2012.04.003Csiki-Sava, Z., Buffetaut, E., Ősi, A., Pereda-Suberbiola, X., & Brusatte, S. L. (2015). Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago. ZooKeys, 469, 1-161. doi:10.3897/zookeys.469.8439Erben, H. K., Hoefs, J., & Wedepohl, K. H. (1979). Paleobiological and isotopic studies of eggshells from a declining dinosaur species. Paleobiology, 5(4), 380-414. doi:10.1017/s0094837300016900García, R. A. (2007). An «egg-tooth»–like structure in titanosaurian sauropod embryos. Journal of Vertebrate Paleontology, 27(1), 247-252. doi:10.1671/0272-4634(2007)27[247:aesits]2.0.co;2Garcia, G., & Vianey-Liaud, M. (2001). Dinosaur eggshells as biochronological markers in Upper Cretaceous continental deposits. Palaeogeography, Palaeoclimatology, Palaeoecology, 169(1-2), 153-164. doi:10.1016/s0031-0182(01)00215-2Grellet-Tinner, G., Chiappe, L. M., & Coria, R. (2004). Eggs of titanosaurid sauropods from the Upper Cretaceous of Auca Mahuevo (Argentina). Canadian Journal of Earth Sciences, 41(8), 949-960. doi:10.1139/e04-049Grigorescu, D., Garcia, G., Csiki, Z., Codrea, V., & Bojar, A.-V. (2010). Uppermost Cretaceous megaloolithid eggs from the Haţeg Basin, Romania, associated with hadrosaur hatchlings: Search for explanation. Palaeogeography, Palaeoclimatology, Palaeoecology, 293(3-4), 360-374. doi:10.1016/j.palaeo.2010.03.031Izquierdo LA, Montero D, Pérez G, Urién V, Meijide M. 2001. Macroestructura de huevos de dinosaurios en el Cretácico superior de “La Rosaca” (Burgos, España). Actas de las I Jornadas Internacionales Sobre Paleontología de Dinosaurios y su Entorno. Ed. Colectivo Arqueológico y Paleontológico de Salas. Salas de los Infantes. p. 389–395.Jackson FD. 2007. Titanosaur reproductive biology: comparison of the Auca Mahuevo Titanosaur nesting locality (Argentina), to the Pinyes Megaloolithus nesting locality (Spain) [PhD dissertation]. Bozeman (MT): Montana State University.Jackson, F. D., Garrido, A., Schmitt, J. G., Chiappe, L. M., Dingus, L., & Loope, D. B. (2004). Abnormal, multilayered titanosaur (Dinosauria: Sauropoda) eggs from in situ clutches at the Auca Mahuevo locality, Neuquen Province, Argentina. Journal of Vertebrate Paleontology, 24(4), 913-922. doi:10.1671/0272-4634(2004)024[0913:amtdse]2.0.co;2Jackson, F. D., Varricchio, D. J., Jackson, R. A., Vila, B., & Chiappe, L. M. (2008). Comparison of water vapor conductance in a titanosaur egg from the Upper Cretaceous of Argentina and a Megaloolithus siruguei egg from Spain. Paleobiology, 34(2), 229-246. doi:10.1666/0094-8373(2008)034[0229:cowvci]2.0.co;2López-Martı́nez, N., Moratalla, J. J., & Sanz, J. L. (2000). Dinosaurs nesting on tidal flats. Palaeogeography, Palaeoclimatology, Palaeoecology, 160(1-2), 153-163. doi:10.1016/s0031-0182(00)00063-8Mohabey, D. M. (1998). Systematics of Indian Upper Cretaceous dinosaur and chelonian eggshells. Journal of Vertebrate Paleontology, 18(2), 348-362. doi:10.1080/02724634.1998.10011063Moratalla JJ. 1993. Restos indirectos de dinosaurios del registro español: paleoicnología de la Cuenca de (Jurásico superior-Cretácico inferior) y paleoología del Cretácico superior [PhD dissertation]. Madrid: Universidad Autónoma de Madrid.Moreno-Azanza, M., Bauluz, B., Canudo, J. I., Gasca, J. M., & Torcida Fernández-Baldor, F. (2016). Combined Use of Electron and Light Microscopy Techniques Reveals False Secondary Shell Units in Megaloolithidae Eggshells. PLOS ONE, 11(5), e0153026. doi:10.1371/journal.pone.0153026Moreno-Azanza, M., Bauluz, B., Canudo, J. I., Puértolas-Pascual, E., & Sellés, A. G. (2013). A re-evaluation of aff. Megaloolithidae eggshell fragments from the uppermost Cretaceous of the Pyrenees and implications for crocodylomorph eggshell structure. Historical Biology, 26(2), 195-205. doi:10.1080/08912963.2013.786067Oms, O., Dinarès-Turell, J., Vicens, E., Estrada, R., Vila, B., Galobart, À., & Bravo, A. M. (2007). Integrated stratigraphy from the Vallcebre Basin (southeastern Pyrenees, Spain): New insights on the continental Cretaceous−Tertiary transition in southwest Europe. Palaeogeography, Palaeoclimatology, Palaeoecology, 255(1-2), 35-47. doi:10.1016/j.palaeo.2007.02.039Ortega, F., Bardet, N., Barroso-Barcenilla, F., Callapez, P. M., Cambra-Moo, O., Daviero- Gómez, V., … Sanz, J. L. (2015). The biota of the Upper Cretaceous site of «Lo Hueco» (Cuenca, Spain). Journal of Iberian Geology, 41(1). doi:10.5209/rev_jige.2015.v41.n1.48657Rasskin-Gutman, D., Elez, J., Esteve-Altava, B., & López-Martínez, N. (2020). Reconstruction of the internal structure of the pore system of a complex dinosaur eggshell (Megaloolithus siruguei). Spanish Journal of Palaeontology, 28(1), 61. doi:10.7203/sjp.28.1.17831Riera, V., Oms, O., Gaete, R., & Galobart, À. (2009). The end-Cretaceous dinosaur succession in Europe: The Tremp Basin record (Spain). Palaeogeography, Palaeoclimatology, Palaeoecology, 283(3-4), 160-171. doi:10.1016/j.palaeo.2009.09.018Sellés, A. G., Bravo, A. M., Delclòs, X., Colombo, F., Martí, X., Ortega-Blanco, J., … Galobart, À. (2013). Dinosaur eggs in the Upper Cretaceous of the Coll de Nargó area, Lleida Province, south-central Pyrenees, Spain: Oodiversity, biostratigraphy and their implications. Cretaceous Research, 40, 10-20. doi:10.1016/j.cretres.2012.05.004Tanaka, K., & Zelenitsky, D. K. (2014). Comparisons between experimental and morphometric water vapor conductance in the eggs of extant birds and crocodiles: implications for predicting nest type in dinosaurs. Canadian Journal of Zoology, 92(12), 1049-1058. doi:10.1139/cjz-2014-0078Vianey-Liaud, M., Khosla, A., & Garcia, G. (2003). Relationships between European and Indian dinosaur eggs and eggshells of the oofamily Megaloolithidae. Journal of Vertebrate Paleontology, 23(3), 575-585. doi:10.1671/0272-4634(2003)023[0575:rbeaid]2.0.co;2Vianey-Liaud, M., & Lopez-Martinez, N. (1997). Late Cretaceous dinosaur eggshells from the Tremp Basin, southern Pyrenees, Lleida, Spain. Journal of Paleontology, 71(6), 1157-1171. doi:10.1017/s002233600003609xVila, B., Galobart, À., Canudo, J. I., Le Loeuff, J., Dinarès-Turell, J., Riera, V., … Gaete, R. (2012). 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Soil-landscape and climatic relationships in the middle Miocene of the Madrid Basin

The Miocene alluvial-lacustrine sequences of the Madrid Basin, Spain, formed in highly varied landscapes. The presence of various types of palaeosols allows assessment of the effects of local and external factors onsedimentation, pedogenesis and geomorphological development. In the northern, more arid, tectonicallyactive arca, soils were weakly developed in aggrading alluvial fans, dominated by mass flows. reflecting high sedimentation rates. In more distal parts of the fans and in playa lakes calcretes and dolocretes developed: the former were associated with Mg-poor fan sediments whitc: the latter formed on Mg-rich lake clays exposed during minar lake lowstands. The nonh-east part of the basin had a less arid climate. Alluvial fans in this area were dominated by stream Aood deposits, sourced by carbonate terrains. Floodplain and freshwater lakc deposits formed in distal areas. The high local supply of calcium carbonate may have contributed to the preferential developmenl on calcretes on the fans. Both the fan and floodplain palaeosols exhibit pedofacies relationships and more mature soils developed in settings more distant from the sediment sources. Palaeosols also developed on pond and lake margin carbonates, and led to the formation of palustrine limestones. The spatial distributions and stratigraphies of palaeosols in the Madrid Basin alluvial fans suggest that soil formation was controlled by local factors. These palaeosols differ from those seen in Quatemary fans. Which are characterized by climatically induced periods of stability and instability

Prokaryotic and Eukaryotic Community Structure in Field and Cultured Microbialites from the Alkaline Lake Alchichica (Mexico)

The geomicrobiology of crater lake microbialites remains largely unknown despite their evolutionary interest due to their resemblance to some Archaean analogs in the dominance of in situ carbonate precipitation over accretion. Here, we studied the diversity of archaea, bacteria and protists in microbialites of the alkaline Lake Alchichica from both field samples collected along a depth gradient (0–14 m depth) and long-term-maintained laboratory aquaria. Using small subunit (SSU) rRNA gene libraries and fingerprinting methods, we detected a wide diversity of bacteria and protists contrasting with a minor fraction of archaea. Oxygenic photosynthesizers were dominated by cyanobacteria, green algae and diatoms. Cyanobacterial diversity varied with depth, Oscillatoriales dominating shallow and intermediate microbialites and Pleurocapsales the deepest samples. The early-branching Gloeobacterales represented significant proportions in aquaria microbialites. Anoxygenic photosynthesizers were also diverse, comprising members of Alphaproteobacteria and Chloroflexi. Although photosynthetic microorganisms dominated in biomass, heterotrophic lineages were more diverse. We detected members of up to 21 bacterial phyla or candidate divisions, including lineages possibly involved in microbialite formation, such as sulfate-reducing Deltaproteobacteria but also Firmicutes and very diverse taxa likely able to degrade complex polymeric substances, such as Planctomycetales, Bacteroidetes and Verrucomicrobia. Heterotrophic eukaryotes were dominated by Fungi (including members of the basal Rozellida or Cryptomycota), Choanoflagellida, Nucleariida, Amoebozoa, Alveolata and Stramenopiles. The diversity and relative abundance of many eukaryotic lineages suggest an unforeseen role for protists in microbialite ecology. Many lineages from lake microbialites were successfully maintained in aquaria. Interestingly, the diversity detected in aquarium microbialites was higher than in field samples, possibly due to more stable and favorable laboratory conditions. The maintenance of highly diverse natural microbialites in laboratory aquaria holds promise to study the role of different metabolisms in the formation of these structures under controlled conditions