Premise of research. Although the most comprehensively known Devonian seeds were borne in a “telomic” cupule, those of some species have been postulated as being borne terminally on naked axes lacking a cupule. Uncertainty remains as to whether such seeds were shed from a cupule before preservation. We reinvestigate the Upper Devonian fossils Pseudosporogonites hallei and Xenotheca bertrandii from Belgium and the similar ovules Aglosperma quadrapartita and Aglosperma avonensis from Britain and Aglosperma sp. from North America to consider their structure and organization and to determine whether they were cupulate. Methodology. Compressions/adpressions of X. bertrandii and Pseudosporogonites from Belgium and A. quadrapartita and A. avonensis from the United Kingdom, as well as Anglosperma sp. from Pennsylvania, were prepared, mainly by dégagement. Observation and photography were carried out using crossed polarizing filters. Pivotal results. Pseudosporogonites hallei, X. bertrandii, and A. quadrapartita comprise single ovules borne within small, radially symmetrical, uniovulate cupules. Integuments are entire at the chalaza but form flattened lobes distally. While a cupule is unknown in A. avonensis, its comparable integument morphology suggests that it was shed from a uniovulate cupule. Although the species are distinct from each other, their similarities show that they are closely related and belong to a single genus, for which the name Pseudosporogonites has priority. We emend P. hallei in light of our findings and erect the combinations P. bertrandii (Stockmans) C. Prestianni, J. Hilton et W. Cressler, P. quadrapartitus (J. Hilton et D. Edwards) C. Prestianni, J. Hilton et W. Cressler, and P. avonensis (J. Hilton) C. Prestianni, J. Hilton et W. Cressler. Conclusions. The uniovulate cupule in Pseudosporogonites is distinct from multiovulate telomic cupules of other Devonian seeds and expands the phenotypic diversity seen during the earliest phase of seed plant radiation, which was geologically instantaneous. Hydrasperman pollination in all proven Devonian seeds demonstrates evolution from a common ancestor, but finding morphological intermediates between seed and free-sporing plants remains a significant challenge to evolutionary plant biology.
Located in
Library
/
RBINS Staff Publications
Spy, a Belgian cave site famous for its Neanderthal remains, contains a wide spectrum of Pleistocene species. Horse, cave hyena, woolly mammoth, woolly rhinoceros and reindeer are the primary taxa. The Spy cave was used alternately by prehistoric humans and Pleistocene carnivores. This study considers whether prehistoric humans or carnivores are responsible for the large number of mammoth remains at the site. It is argued, on the basis of the frequency distribution of the skeletal elements of the mammoth, the age distribution of the mammoth molars, and the diet of the large carnivores and of the prehistoric humans, that the mammoth assemblage of Spy accumulated at the site through the activities of prehistoric humans. On the basis of AMS dates, the stratigraphic position of a number of mammoth molars and the absence of red ochre on the mammoth molars, it was concluded that these prehistoric humans were Neanderthals rather than Anatomically Modern Humans.
Located in
Library
/
RBINS Staff Publications