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Specimens of Eurypterus are the most common eurypterid fossils worldwide. They are particularly abundant in the Silurian Bertie Group of North America. The Bertie Group Eurypterus species are relatively small compared with associated giants such as Acutiramus, Eusarcana, and Dolichopterus. Here we report the discovery of an isolated telson of Eurypterus lacustris nearly 15 cm long indicating an individual more than half a meter in length. This highly maneuverable swimmer with acute vision joins the list of eurypterid predators with giant representatives.
Percina freemanorum, the Etowah Bridled Darter, is described as a new species endemic to the Etowah River system in Georgia, specifically in Long Swamp Creek, Amicalola Creek, and the upper portion of the Etowah River. The earliest collection records for Percina freemanorum date to 1948 and in 2007 the species was delimited as populations of Percina kusha. Our investigation into the systematics of Percina kusha is motivated by the uncertain status of populations in the Coosawattee River system and observed morphological disparity in several meristic traits between populations in the Conasauga and Etowah River systems. Our analyses of morphological divergence, nuclear genotypes, and mitochondrial DNA (mtDNA) haplotype networks confirm the distinctiveness of Percina freemanorum. Morphologically, Percina freemanorum is distinguished from Percina kusha through lower average numbers of lateral line scales (65.4 vs. 72.3); rows of transverse scales (18.0 vs. 21.4); scales around the caudal peduncle (22.1 vs. 24.9); and modally more pectoral fin rays (14 vs. 13). The two species are not reciprocally monophyletic in phylogenetic analysis of mtDNA sequences, but the two species do not share mtDNA haplotypes. Analysis of up to 158,000 double digest restriction-site associated DNA (ddRAD) sequencing loci resolve each of the two species as reciprocally monophyletic and genomic clustering analysis of single nucleotide polymorphisms identifies two genetic clusters that correspond to the morphologically delimited Percina freemanorum and Percina kusha.
Turtles of the clade Testudinoidea have a rather scarce fossil record in Afro-Arabia, ranging from the late Eocene up to the Quaternary. The vast majority of testudinoid fossils from Afro-Arabia are ascribed to Testudinidae, which has had a continuous presence in the area since the late Eocene. Geoemydidae is poorly documented by fragments found throughout the Neogene across northern Africa and the Middle East. Emydidae is absent from the fossil record of this area. All valid named taxa pertain to testudinids. Within Testudinidae, the majority of known fossil species are members of the clade Geochelona, while a few others belong to the clade Testudona. Four fossil taxa are members of now-extinct genera, five are members of extant genera, and seven cannot be assigned to a known genus with certainty. The fossil record also documents that several extant genera had a much broader distribution during the Neogene and Quaternary. Endemic insular lineages were formerly present on the Canary Islands, Cape Verde islands, and on several islands in the Western Indian Ocean. The highest known diversity of testudinoids seems to have existed during the Neogene; however, definitive conclusions are hampered by the extremely poor Paleogene record and large, unsampled areas of Afro-Arabia. A taxonomic review of the 22 named Afro-Arabian taxa finds 16 nomina valida, 1 nomen invalidum, and 5 nomina dubia.