Where is genus Leptaena found?
Leptaena fossils have been found on every continent except Antarctica.
When did Leptaena live?
Leptaena, genus of extinct brachiopods (lamp shells) commonly found as fossils in Ordovician to Lower Carboniferous sedimentary rocks (between 488 million and 318 million years old).
What is the salient features of Leptodus?
Leptodus, a very specialized form characterized by an aberrant morphology, had an oysterlike pedicle valve, which anchored the shell to the substrate and was probably attached to other shells by cementation. The brachial (upper) valve was flat and very thin.
Is Archimedes an index fossil?
This is Archimedes, an excellent index fossil found only in Mississippian aged rocks. The spiral portion represents the stalk that supported a lacy or net-like part of the colony.
Who discovered genus Archimedes?
This prototype for the name given by Lesueur and Owen to the fossil genus Archimedes was invented by Archimedes about 2250 years ago.
What is a Parafusulina bosei?
Parafusulina, genus of extinct fusulinid foraminiferans (single-celled animals with a hard, complexly constructed shell) found as fossils in Permian marine rocks (the Permian Period began 299 million years ago and ended 251 million years ago).
What is Dictyoclostus americanus?
Dictyoclostus, genus of extinct brachiopods, or lamp shells, that were common invertebrate forms in the shallow seas of North America from the Carboniferous to the Permian periods (between 359 million and 251 million years ago).
What are Archimedes fossils?
Archimedes is a fossil that looks like a screw. It is a genus of fenestrate bryozoans, defined by a corkscrew-shaped axial support column and spiraling mesh-like fronds attached to the column. Broken fragments of Archimedes are common in Mississippian rocks of both eastern and western Kentucky.
What is a Brachiopod fossil?
Brachiopods (brack’-i-oh-pods) are marine animals with two shells, an upper one and a lower one. The oldest fossil brachiopods are found in Cambrian rocks, which are over 500 million years old. The animals first became abundant in Ordovician time and remained so throughout the Paleozoic Era.
How old is Parafusulina bosei?
What is an index fossil and how is it used?
Index fossils are used to define geological periods. These fossils can be defined as “commonly found, widely distributed fossils that are limited in time span.” If one finds an index fossil in a given layer, then one has bounds on the age of the layer. Using index fossils, the geological periods are defined.
What is a gastropod fossil?
Gastropods are snail-like and slug-like invertebrate (lacking a backbone) animals, and are types of mollusks. Because fossils mostly represent the hard parts of organisms, snails are the most common types of gastropod fossils. Slugs are not preserved as fossils. Snails have a single, coiled shell.
How many species of Leptaena are there in the world?
Leptaena was a diverse genus, with over 70 recognized species and subgenera. Species in the genus Leptaena include the following. Any synonymous genera to which a given species may belong to are labelled with the synonymous genus in parentheses. ^ a bPlaza-Torres, Stephanie; Darroch, Simon; Wagner, Peter.
What kind of shell does the Leptaena have?
Leptaena is recorded from the Cincinnatian Series and ranges into the Devonian of Ohio. Concavo-convex, finely striated Strophomenids characterized by a conspicuous concentric wrinkling of the shell which is abruptly deflected anteriorly.
What kind of animal is a Leptaena brachiopod?
A medium-sized to large, concavoconvex strophomenid brachiopod. Its semicircular outline is truncated by a straight hinge line. Leptaena is characteristically wider than long and has concentric ridges or rugae.