During the Late Devonian Biodiversity Crisis, the primary driver of biodiversity decline was the dramatic reduction in speciation rates, not elevated extinction rates; however, the causes of speciation decline have been previously unstudied. Speciation, the formation of new species from ancestral populations, occurs by two primary allopatric mechanisms: vicariance, where the ancestral populatio...

members of the family laccophyllidae are small, solitary rugose corals with stratigraphic ranges from silurian to permian. among the laccophyllids, axial ends of major septa are united in an aulos and dissepiments may be absent or present. minor septa can be contratingent and sometimes are small or in some genera are absent. septa and aulos may be thick or thin. in this study, famennian rugose ...

Complete, exceptionally-preserved skulls of the Permian lungfish Persephonichthys chthonica gen. et sp. nov. are described. Persephonichthys chthonica is unique among post-Devonian lungfishes in preserving portions of the neurocranium, permitting description of the braincase of a stem-ceratodontiform for the first time. The completeness of P. chthonica permits robust phylogenetic analysis of th...

Carbon isotope (N13C) analyses of marine carbonates spanning the Silurian^Devonian transition are compared from three richly fossiliferous, well-dated sequences in North America. The three sections, in the central Appalachian Mountains (West Virginia), Great Basin (Nevada), and the southern Mid-continent (Oklahoma), reveal positive N13C shifts beginning in the late Pridoli and reaching peak val...

Hyneria lindae, gen. et sp. nov., is a large rhizodontid rhipidistian fish from the Upper Devonian (Oswayo Formation) of Pennsylvania. It shows a remarkable similarity to the intermediate stages that must have preceded the first true Amphibia. The similarity is due to the parallel evolution of rhizodontid Rhipidistia and the Amphibia from a common stock in the Middle or early Late Devonian. POS...

The stratifi ed red beds of the Catskill Formation are conspicuous in road cut exposures on the Allegheny Plateau of north-central Pennsylvania. During this fi eld trip we will visit and explore several fossil localities within the Catskill Formation. These sites have been central to recent investigations into the nature of Late Devonian continental ecosystems. By the Late Devonian, forests wer...

The new genus and species, Gondwanascorpio emzantsiensis, are described in Scorpiones incertae se dis on the basis of fragments from the Famennian (Late Devonian) Waterloo Farm locality near Grahams town, Eastern Cape, South Africa. This finding adds to the sparse record of Late Devonian scorpion taxa and provides the first evidence of Palaeozoic scorpions from Gondwana. Material includes a com...

Well exposed Famennian, mainly carbonate rocks of the Bahram Formation in the vicinity of Bagher Abad village, Central Iran,yielded chondrichthyan teeth some sarcopterygii and actinopterygii teeth and fragments. Three different genera were recognizedamong the chondrichthyan teeth represented by: Phoebodus turnerae, Ph. spp., Deihim mansureae (M2, M3), Stethacanthus sp..Acanthodian and sarcopter...

Members of the family Laccophyllidae are small, solitary rugose corals with stratigraphic ranges from Silurian to Permian. Among the laccophyllids, axial ends of major septa are united in an aulos and dissepiments may be absent or present. Minor septa can be contratingent and sometimes are small or in some genera are absent. Septa and aulos may be thick or thin. In this study, Famennian rugose...