Asian mock vipers of the genus Psammodynastes and African forest snakes of the genus Buhoma are two genera belonging to the snake superfamily Elapoidea. The phylogenetic placements of Psammodynastes and Buhoma within Elapoidea has been extremely unstable which has resulted in their uncertain and debated taxonomy. We used ultraconserved elements and traditional nuclear and mitochondrial markers to infer the phylogenetic relationships of these two genera with other elapoids. Psammodynastes, for which a reference genome has been sequenced, were found, with strong branch support, to be a relatively early diverging split within Elapoidea that is sister to a clade consisting of Elapidae, Micrelapidae and Lamprophiidae. Hence, we allocate Psammodynastes to its own family, Psammodynastidae new family. However, the phylogenetic position of Buhoma could not be resolved with a high degree of confidence. Attempts to identify the possible sources of conflict in the rapid radiation of elapoid snakes suggest that both hybridisation/introgression during the rapid diversification, including possible ghost introgression, as well as incomplete lineage sorting likely have had a confounding role. The usual practice of combining mitochondrial loci with nuclear genomic data appears to mislead phylogeny reconstructions in rapid radiation scenarios, especially in the absence of genome scale data.
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RBINS Staff Publications 2024
This study aims to quantify the intensity and diversity of plant-insect associations observed in the fossil assemblage of Gelinden, Limburg, Belgium. The site yields a rich collection of well-preserved plant remains, mainly leaves, from a Paleocene European temperate forest. The 780 specimens presented here were scanned using standardized morphotype systems for any trace of damage. This raw data was then used to quantify the intensity and diversity of interactions in the Gelinden flora. This material showed an impressive richness of interactions, contrasting with the poor North American sites covering the period that followed the Cretaceous-Paleogene extinction. Both hosts and interaction types observed at Gelinden are two to three times more abundant than in most American floras, in raw numbers and leaf area affected. This is coherent with what has been observed in the few other studies conducted in Europe, South America and Antarctica, pointing toward more regionalized effects of the extinction than previously assumed based on American findings. This greater richness implies that these sites were either less affected or quicker to recover from the Cretaceous/Paleogene extinction, questioning its global impact, at least on the lower levels of the food web, as discussed in the following paper.
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RBINS Staff Publications 2023
Platychelone emarginata Dollo, 1909 is a large turtle from the Late Cretaceous (Maastrichtian) chalk sediments of Limburg, Belgium. Hitherto, only the name was given to this turtle without describing details or providing figures. A single well articulated carapace (IRScNB. Reg. 1681), lacking nuchal, peripherals, and pygal plates, is preserved. The distance from the first costal to the distal end of the eighth costal is 180 cm, indicating that the original carapace was about 210 cm long. Its gigantic size, flattened shell, reduction of distal half of costals, and loss of scute sulcus, indicate that Platychelone is a member of true marine turtles (superfamily Chelonioidea). Neurals are rectangular shape and inclination of the first thoracic vertebra is almost vertical, suggesting this turtle belongs to either Protostegidae or Dermochelyidae. Seventh and eighth costals are medially meeting due to the loss of neurals; this condition is shared with the genus Mesodermochelys from the Late Cretaceous (Santonian to Maastrichtian) of Japan. Thus, it seems most probable that Platychelone is a closest relative of Mesodermochelys among basal dermochelyids. Platychelone has presumed autoapomorphic characters such as very thickened distal ends of thoracic ribs and irregular sculptures on carapace, not seen in any other chelonioids. This genus is only known by the holotype, whereas Allopleuron hoffmanni, a very common cheloniid marine turtle from in the Maastrichtian deposits of Belgium and Netherland, is known from some hundred specimens. So far, there is no ancestral or related taxon of Platychelone from the Campanian deposits of Belgium. The occurrence of Platychelone is very rare but evokes a high taxonomic diversity of gigantic chelonioids in the Cretaceous Tethys.
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RBINS Staff Publications 2017
