Palaeoworld最新文献

Reproductive organs and in situ spores isolated from early land plant Tichavekia grandis from the Kosov, Přídolí, upper Silurian of the Prague Basin are described in detail. Subspherical to reniform sporangia are 2.2–3.0 mm wide and 1.6–2.0 mm long, and are formed by a thick layer of coaly matter showing a marginal rim. Trilete crassitate in situ spores 17–32 µm in diameter have microgranulate, microspinate to rugulate sculpture of proximal surface and are not comparable with any dispersed and in situ Silurian spore taxa and, therefore, it may represent a new spore taxon. Palynological comparison with other cooksonioid taxa is made.

A feature that distinguishes angiosperms from their gymnosperm peers is that the ovules of angiosperms are enclosed before pollination. Theoretically, the angiosperms were derived from fossil seed plants that have their ovules not enclosed before pollination (gymnosperms). The origin of angiosperms is essentially a process in which the former exposed ovules got enclosed. Although various fossil taxa with different extent of ovule-protection have been documented in the Mesozoic, the morphological gap between angiosperms and gymnosperms is still far from bridged. To narrow down such a gap, here we report a novel fossil gymnosperm, Paradoxa n. gen., demonstrating a mosaic feature comparable to angiosperms in certain aspects from the Jiulongshan Formation (Middle-Late Jurassic) of Inner Mongolia, China: pollen grains trapped inside the female unit imply that Paradoxa is a gymnosperm, while several characters (especially long apical process and partially covered ovule) make it more comparable to angiosperms. It is noteworthy that, different from Caytonia, Umkomasia and Petriellaea (all in the so-called seed ferns), Paradoxa’s Bau-plan is more comparable to that of the basalmost angiosperm Amborella, suggesting a possible provenance of angiosperm carpels.

The knowledge of the paleopathologies that affected large mammals during the Pleistocene of South America has increased in the last years, but most of the reported cases belong to the endemic clade Xenarthra. On the contrary, almost no case of diseases is known among representatives of other clades, such as Carnivora. Here we present and describe an inflammatory lesion in a left metacarpal IV assigned to the saber tooth Smilodon populator (Felidae) from the Late Pleistocene (ca. 100 ka; MIS 5) of Northeastern Argentina. The macroscopic and radiologic analyses reveal features consistent with chronic osteomyelitis, which in turn represents the first accurate record of an infectious process in a limb of this predator. This injury presumably caused lameness and loss of toe flexion, and considerably reduced the hunting abilities of this top predator, which used its robust forelimbs, particularly wide forepaws, and powerful back muscles to catch and bring down large prey.

Two partly anatomically preserved axes parallelly situated on a slab collected from an in situ volcanic ash bed called “Bělka” of the Whetstone Horizon, Kladno Formation (Pennsylvanian), Czech Republic, were studied in detail. Anatomically, both axes possess a C-shaped xylem strand with protoxylem tracheids situated on the convex side, demonstrating an inversicatenalean-type anachoropterid affiliation. They are further suggested to belong to one biological species, as they share a number of similar characteristics and common structures. Systematically, one of the two studied axes retains a primitive form of foliar anatomy with the oldest known anachoropterid plant (Anachoropteris sp.) in having two rather short lateral arms compared to the long median region. Although lacking foliage information, both axes likely belong to the rachis part of Discosoropteris zlatkokvacekii Pšenička, Zhou, Boyce, Votočková Frojdová, Bek and Wang, a fern species that was recently established based on the same slab where the two studied axes were preserved. Such a combination may further indicate the presence of a new family in the late Paleozoic anachoropterid plants. In addition, selected anatomically preserved ferns from the Whetstone Horizon were reviewed, which promotes a better understanding of the anatomical variability of fern species.

A well-preserved radiolarian assemblage was recovered from the Upper Jurassic section near the Rybaki village, Moscow Region, Central Russia. The radiolarians were found within the Amoeboceras serratum ammonite zone (upper Oxfordian), in phosphatized body chambers of ammonite shells. The radiolarian assemblage is represented by 23 species of 11 genera and displays Boreal affinity. It is characterized by abundance of Praeparvicingula: P. blackhorsensis (Pessagno and Whalen), P. donnae Bragin, P. elementaria (Carter), P. enormis (Yang) and by presence of the characteristic boreal family Echinocampidae (genera Echinocampe and Nordvikella). Five new species are described.