Egg fossils are the fossilized remains of eggs laid by ancient animals . As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil . Under rare circumstances a fossil egg may preserve the remains of the once- developing embryo inside, in which case it also contains body fossils . A wide variety of different animal groups laid eggs that are now preserved in the fossil record beginning in the Paleozoic . Examples include invertebrates like ammonoids as well as vertebrates like fishes , possible amphibians , and reptiles . The latter group includes the many dinosaur eggs that have been recovered from Mesozoic strata . Since the organism responsible for laying any given egg fossil is frequently unknown, scientists classify eggs using a parallel system of taxonomy separate from but modeled after the Linnaean system . This " parataxonomy " is called veterovata .
20-820: The first named oospecies was Oolithes bathonicae , a name given provisionally by Professor J. Buckman to a group of eggs which Buckman believed were laid by a teleosaur . However, modern scientists no longer think it is possible to determine what kind of reptile laid these eggs. In 1859, the first scientifically documented dinosaur egg fossils were discovered in southern France by a Catholic priest and amateur naturalist named Father Jean-Jacques Poech , however he thought they were laid by giant birds. The first scientifically recognized dinosaur egg fossils were discovered serendipitously in 1923 by an American Museum of Natural History crew while looking for evidence of early humans in Mongolia. Egg discoveries continued to mount all over
40-431: A 'cf.' (from Latin confer , compare, before a taxon name); such a convention is especially widespread in palaeontology. In zoological nomenclature, " incertae sedis " is not a nomenclatural term at all per se , but is used by taxonomists in their classifications to mean "of uncertain taxonomic position". In botany, a name is not validly published if it is not accepted by the author in the same publication. In zoology,
60-523: A communication to the 4 May 1859 meeting of the Geological Society (published in 1860). Buckman believed that Oolithes represented the eggs of a teleosaurian reptile . Since Buckman's description of O. bathonicae , two other oospecies have been named: O. nanhsiungensis and O. spheroides , both of which were native to the Maastrichtian of China . This egg fossil-related article
80-447: A formal phylogenetic analysis is conducted that does not include a certain taxon, the authors might choose to label the taxon incertae sedis instead of guessing its placement. This is particularly common when molecular phylogenies are generated, since tissue for many rare organisms is hard to obtain. It is also a common scenario when fossil taxa are included, since many fossils are defined based on partial information. For example, if
100-429: A name proposed conditionally may be available under certain conditions. For uncertainties at lower levels, some authors have proposed a system of "open nomenclature", suggesting that question marks be used to denote a questionable assignment. For example, if a new species was given the specific epithet album by Anton and attributed with uncertainty to Agenus , it could be denoted " Agenus ? album Anton (?Anton)";
120-402: A taxon, which may be expressed, among others, by using a question mark after or before a taxon name. This should be distinguished from the situation where either it is uncertain how to use a name, often because the types have been lost ( nomen dubium , species inquirenda ), or whether a poorly preserved specimen should be included within a given species or genus, which is often expressed using
140-428: Is a stub . You can help Misplaced Pages by expanding it . Incertae sedis Incertae sedis ( Latin for 'of uncertain placement') or problematica is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature , uncertainty at specific taxonomic levels
160-535: Is indicated by incertae familiae (of uncertain family), incerti subordinis (of uncertain suborder), incerti ordinis (of uncertain order) and similar terms. When formally naming a taxon, uncertainty about its taxonomic classification can be problematic. The International Code of Nomenclature for algae, fungi, and plants , stipulates that "species and subdivisions of genera must be assigned to genera, and infraspecific taxa must be assigned to species, because their names are combinations", but ranks higher than
180-413: Is not always followed. They are divided up into several basic types: Testudoid, Geckoid, Crocodiloid, Dinosauroid-spherulitic, Dinosauroid-prismatic, and Ornithoid. Veterovata does not always mirror the taxonomy of the animals which laid the eggs. The oogenus level parataxonomy of Veterovata, following Lawver and Jackson (2014) for Testudoid, Hirsch (1996) for Geckonoid eggs, and Mikhailov et al. (1996) for
200-731: The Devonian and spanning into the Cenozoic era . The eggs of many different fish taxa have contributed to this record, including lobe-finned fish , placoderms , and sharks . Occasionally eggs are preserved still within the mother's body, or associated with fossil embryos . Some fossil eggs possibly laid by fish cannot be confidently distinguished from those laid by amphibians . Several fossilized fish or amphibian eggs have been classified as ichnogenera, including Mazonova , Archaeoovulus , Chimaerotheca , Fayolia , and Vetacapsula . The fossil record of reptile eggs goes back at least as far as
220-546: The Early Permian . However, since the earliest reptile eggs probably had soft shells with little preservation potential , reptilian eggs may go back significantly farther than their fossil record. Many ancient reptile groups are known from egg fossils including crocodilians , dinosaurs , and turtles. Some ancient reptiles, like ichthyosaurs and plesiosaurs are known to have given live birth and are therefore not anticipated to have left behind egg fossils. Dinosaur eggs are among
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#1733086157720240-462: The fossil record of cephalopod eggs is scant since their soft, gelatinous eggs decompose quickly and have little chance to fossilize. Another major group of Mesozoic cephalopods, the belemnoids , have no documented eggs in the fossil record whatsoever, although this may be because scientists have not properly searched for them rather than an actual absence from the fossil record. Fossil fish eggs have an extensive record going at least as far back as
260-553: The genus may be assigned incertae sedis . This excerpt from a 2007 scientific paper about crustaceans of the Kuril–Kamchatka Trench and the Japan Trench describes typical circumstances through which this category is applied in discussing: ...the removal of many genera from new and existing families into a state of incertae sedis. Their reduced status was attributed largely to poor or inadequate descriptions but it
280-480: The "(?Anton)" indicates the author that assigned the question mark. So if Anton described Agenus album , and Bruno called the assignment into doubt, this could be denoted " Agenus ? album (Anton) (?Bruno)", with the parentheses around Anton because the original assignment (to Agenus ) was modified (to Agenus ?) by Bruno. This practice is not included in the International Code of Zoological Nomenclature , and
300-620: The early 1990s Russian paleontologist Konstantin Mikhailov brought attention to Zhao's work in the English language scientific literature . Eggs laid by invertebrate animals are known from the fossil record. Among these are eggs laid by ancient cephalopods . Eggs laid by ammonoids are the best known cephalopod egg fossils. The best preserved fossil ammonite eggs were preserved in the Jurassic Kimmeridge Clay of England . Nevertheless,
320-429: The most well known kind of fossil reptile eggs. Fossil eggs are classified according to the parataxonomic system called Veterovata. There are three broad categories in the scheme, on the pattern of organismal phylogenetic classification, called oofamilies, oogenera and oospecies (collectively known as ootaxa). The names of oogenera and oofamilies conventionally contain the root "oolithus" meaning "stone egg", but this rule
340-478: The phylogeny was constructed using soft tissue and vertebrae as principal characters and the taxon in question is only known from a single tooth, it would be necessary to label it incertae sedis . If conflicting results exist or if there is not a consensus among researchers as to how a taxon relates to other organisms, it may be listed as incertae sedis until the conflict is resolved. The term incertae sedis refers to uncertainty about phylogenetic position of
360-430: The rest unless otherwise noted: Testudoid Geckonoid Crocodiloid Mosasauroid Dinosauroid-spherulitic Dinosauroid-prismatic Ornithoid Incertae sedis /Unclassified Oolithes Oolithes is an oogenus with uncertain affinities . It has historical significance because it was the earliest named oogenus. James Buckman described the first named species as Oolithes bathonicae in
380-482: The world, leading to the development of multiple competing classification schemes. In 1975 Chinese paleontologist Zhao Zi-Kui started a revolution in fossil egg classification by developing a system of " parataxonomy " based on the traditional Linnaean system to classify eggs based on their physical qualities rather than their hypothesized mothers. Zhao's new method of egg classification was hindered from adoption by Western scientists due to language barriers. However, in
400-430: Was accepted that some of the vagueness in the analysis was due to insufficient character states. It is also evident that a proportion of the characters used in the analysis, or their given states for particular taxa, were inappropriate or invalid. Additional complexity, and factors that have misled earlier authorities, are intrusion by extensive homoplasies , apparent character state reversals and convergent evolution . If
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