Seven Stars was home to a stunning, diverse ecosystem that sustained a vast array of organisms. It was only able to do so because of a complex chain of geological events that set up the area for the life documented here. The Seven Stars ecosystem was heavily influenced by the step-by-step formation of the modernContinue reading “Geological Background of Seven Stars”
Category Archives: Seven Stars
Polychaetes
Polychaetes, segmented worms bearing parapodia, are first found in the Cambrian Period, and all exhibit an elongated body broken into many segments. More specifically, the Polychaete worms within the order Eunicida are also first found in the Cambrian and are further characterized by ventral maxillae and dorsal mandibles positioned within the pharynx. Eunicids are foundContinue reading “Polychaetes”
Crinoids
Crinoids were enormously successful Echinoderms that lived all over the world, starting in the Cambrian and living on today with roughly 80 species (1). Their columnals, sections of their stems, preserve especially well as fossils, and their filter feeding habits enabled them to thrive in a plethora of marine environments. Crinoids found at Seven StarsContinue reading “Crinoids”
Conodonts
Conodonts are perhaps the most important fossils to our daily life because of their use as index fossils. Their “teeth,” called conodont elements, preserve well and can be found in almost any Paleozoic sedimentary rock. While traditionally seen as vertebrates, even fish, their taxonomic positions are still disputed (4). Conodonts found at Seven Stars ConodontaContinue reading “Conodonts”
Hyolitha
Hyolithids were organisms with conical shells with a triangular cross section that have been attributed to Annelid worms, Mollusks, and even a new phylum. More recently they have been confirmed to have been lophophorates and their mode of life uncovered. Hyoliths ranged from the Cambrian to the Permian, but were rare in the late Paleozoic.Continue reading “Hyolitha”
Cephalopods
Cephalopods were mollusks, like gastropods, scaphopods, chitons, and bivalves. Like many mollusks they had shells made of calcium carbonate and processed food with a toothed, tongue-like radula. Cephalopods are still alive today, and include the nautilus, squid, cuttlefish, octopuses, and others. Cephalopods found at Seven Stars Agoniatites vanuxemi VERY RARE Bactrites aciculum UNCOMMON Michelinoceras telamonContinue reading “Cephalopods”
Brachiopods
Brachiopods are one of the most common fossils found at Seven Stars. They were lophophorates, meaning that like Bryozoans, Tentaculitids, Phoronid worms, and Hyolithids, they used an organ called a lophophore to filter plankton and other food from the water(1,2,3,4,5). Some Brachiopods are still alive today, but in much diminished numbers – less than 5%Continue reading “Brachiopods”