A palynological investigation of plesiosaur-bearing rocks from the Upper Cretaceous Tahora Formation,Mangahouanga, New Zealand

High-palaeolatitude plesiosaur, mosasaur and, more rarely, dinosaur fossils are well known from the Maungataniwha Sandstone Member of the Tahora Formation in Mangahouanga Stream, Hawkes Bay, New Zealand. A palynological investigation of strata exposed along Mangahouanga Stream and of transported boulders hosting vertebrate fossils reveals well-preserved assemblages dominated by terrestrial pollen and spores but also including marine dinoflagellate cysts in some samples. The palynofacies are strongly dominated by wood fragments including charcoal; one outcrop sample and the sample taken from a boulder hosting plesiosaur vertebrae contain entirely terrestrially derived palynoassemblages, suggesting a freshwater habitat for at least some of the plesiosaurs. The host unit spans the Santonian to lowermost Maastrichtian, while the key pollen taxa Nothofagidites senectus and Tricolpites lilliei, together with the dinocyst Isabelidinium pellucidum and the megaspore Grapnelispora evansii, indicate a late Campanian to early Maastrichtian age for the fossiliferous boulders. The palynoflora indicates a mixed local vegetation dominated by podocarp conifers and angiosperms with a significant tree-fern subcanopy. The presence of taxa with modern temperate distributions, such as Nothofagus (southern beech), Proteaceae and Cyatheaceae (tree-ferns), indicates a mild-temperate climate and lack of severe winter freezing during the latest Cretaceous, providing an ecosystem that most probably made it possible for polar dinosaurs to overwinter in this part of the world.     

Thomas Jefferson on the Character of an Unfree People: The Case of Spanish America

Thomas Jefferson perceived the people of Spanish America during their revolutionary struggles of the 1810s through the lens of national historical development, formulating an ambiguous attitude toward them. Although welcoming their independence movements, he questioned their ability to establish free, self‐governing republics believing that they needed to undergo a process of political maturation so that they could develop a republican character. As well as regarding the newly liberated countries of Spanish America as potential allies of the United States, Jefferson expressed concern about their becoming its economic and political rivals. Experiencing the new states as scenes of permanent military conflicts, he even suggested temporary restoration of metropolitan control over them by Spain.     

A new Maastrichtian-Paleocene Azolla species from of Bolivia,with a comparison of the global record of coeval Azolla microfossils

A new heterosporous fern species, Azolla boliviensis sp. nov., is described from latest Maastrichtian (latest Cretaceous) to Paleocene (earliest Palaeogene) terrestrial sediments of the Eslabón and Flora Formations, Subandean belt, Bolivia. The species is represented by dissociated but abundantly co-preserved megasporocarps, megaspores, microsporangia, massulae and microspores. The genus consistently characterizes warm-climate lacustrine settings. Fossil Azolla is first identified around the Early to mid-Cretaceous but the genus apparently underwent dramatic radiation during the Late Cretaceous. Abundant Azolla remains in Bolivia add to this portrait of rapid geographie dispersai and diversification near the close of the Cretaceous. The ranges of many Azolla species span the Cretaceous- Palaeogene boundary and the potential of Azolla to withstand altered environmental conditions, such as periodic frost damage, drought, and salinity change, and its ability to undergo rapid vegetative regeneration in association with nitrogen-fixing cyanobacterial symbionts, suggest that the survival of this group was favoured during the adverse conditions of the end-Cretaceous event.     

Triassic palynostratigraphy and palynofloral provinces: evidence from southern Xizang (Tibet), China

Peng, J., Li, J., Slater, S.M., Li, W., Zhu, H. & Vajda, V. October 2017. Triassic palynostratigraphy and palynofloral provinces: evidence from southern Xizang (Tibet), China. Alcheringa 42, 67–86. ISSN 0311-5518.

Palynological analysis was carried out on Middle to Upper Triassic strata from Tulong, Nyalam County, southern Xizang (Tibet), China. Well-preserved miospore (pollen and spore) assemblages and sparse acritarch occurrences were identified. We recognized four formal and one informal biozones based on stratigraphically important taxa and compositional changes through the succession, in ascending order: the Triplexisporites Interval Zone (Anisian), the Staurosaccites quadrifidus Taxon-range Zone (upper Anisian to lower Norian), the Striatella Interval Zone (lower Norian), the Craterisporites rotundus Taxon-range Zone (middle to upper Norian) and the informal ‘Dictyophyllidites harrisii zone’ (Rhaetian). The zonation was supported by marine fossils (e.g., ammonoids and conodonts), and compositional similarity between the zones was examined using non-metric multidimensional scaling (NMDS). Correlation with other representative palynological sequences across Gondwana was also conducted. The presence of miospore taxa not previously recovered from the Late Triassic North and South China palynofloral provinces (e.g., Ashmoripollis reducta, Craterisporites rotundus, Enzonalasporites vigens, Minutosaccus crenulatus, Samaropollenites speciosus and Staurosaccites quadrifidus) calls for a new province in southwestern China, i.e., the Southern Xizang Province. It is proposed here that the modern expression of the northern boundary runs along the Yarlung Zangbo Suture, the remnant of the Tethys that separated the Indian Plate (southern Xizang) and the Lhasa Block during the Late Triassic. This new palynofloral province comprises typical elements of the Onslow Microflora, indicating the need for an extension of this microflora in southern Xizang, China.

Jungang Peng [jgpeng@nigpas.ac.cn], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China, University of Chinese Academy of Sciences, Beijing 100049, China, Department of Palaeobiology, Swedish Museum of Natural History, Stockholm 104 05, Sweden; Jianguo Li* [jgli@nigpas.ac.cn], Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Wenben Li [wenbenli@126.com], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Sam M. Slater [sam.slater@nrm.se], Vivi Vajda [vivi.vajda@nrm.se], Department of Palaeobiology, Swedish Museum of Natural History, Stockholm 104 05, Sweden; Huaicheng Zhu [hczhu@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.