Egg fossils are the

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

ized remains of

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s laid by

ancient Ancient history is a time period from the beginning of writing and recorded human history through late antiquity. The span of recorded history is roughly 5,000 years, beginning with the development of Sumerian cuneiform script. Ancient h ...

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s. As evidence of the

physiological Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

processes of an animal, egg fossils are considered a type of

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

. Under rare circumstances a fossil egg may preserve the remains of the once- developing

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

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 The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...

. Examples include

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s like

ammonoids Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

as well as

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s like

fishes A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed ...

, possible

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s, and

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

s. The latter group includes the many

dinosaur egg Dinosaur eggs are the organic vessels in which a dinosaurs, dinosaur embryo develops. When the first scientifically documented remains of non-avian dinosaurs were being described in England during the 1820s, it was presumed that dinosaurs had la ...

s that have been recovered from

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

. 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 Linnaean taxonomy can mean either of two related concepts: # The particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his ''Systema Naturae'' (1735) and subsequent works. In the taxonomy of Linnaeus th ...

. This "

parataxonomy Parataxonomy is a system of labor division for use in biodiversity research, in which the rough sorting tasks of specimen collection, field identification, documentation and preservation are conducted by primarily local, less specialized individu ...

" is called ''veterovata''.

History

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 Teleosauridae is a family of extinct typically marine crocodylomorphs similar to the modern gharial that lived during the Jurassic period. Teleosaurids were thalattosuchians closely related to the fully aquatic metriorhynchoids, but were less ...

. 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 A priest is a religious leader authorized to perform the sacred rituals of a religion, especially as a mediatory agent between humans and one or more deity, deities. They also have the authority or power to administer religious rites; in parti ...

and amateur naturalist named Father

Jean-Jacques Poech Jean-Jacques is a French name, equivalent to "John James" in English. Since the second half of 18th century, Jean Jacques Rousseau was widely known as Jean Jacques. Notable people bearing this name include: Given name * Jean-Jacques Annaud (born 19 ...

, however he thought they were laid by giant birds. The first scientifically ''recognized'' dinosaur egg fossils were discovered

serendipitously Serendipity is an unplanned fortunate discovery. The term was coined by Horace Walpole in 1754. The concept is often associated with scientific and technological breakthroughs, where accidental discoveries led to new insights or inventions. Man ...

in 1923 by an

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

crew while looking for evidence of

early humans ''Homo'' () is a genus of great ape (family Hominidae) that emerged from the genus ''Australopithecus'' and encompasses only a single extant species, ''Homo sapiens'' (modern humans), along with a number of extinct species (collectively called ...

in Mongolia. Egg discoveries continued to mount all over the world, leading to the development of multiple competing classification schemes. In 1975 Chinese paleontologist

Zhao Zi-Kui Zhao may refer to: * Zhao (surname) (赵), a Chinese surname ** commonly spelled Chao in Taiwan or up until the early 20th century in other regions ** Chiu, from the Cantonese pronunciation ** Cho (Korean surname), represent the Hanja 趙 (Chine ...

started a revolution in fossil egg classification by developing a system of "

" 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 the early 1990s Russian paleontologist Konstantin Mikhailov brought attention to Zhao's work in the English language

scientific literature Scientific literature encompasses a vast body of academic papers that spans various disciplines within the natural and social sciences. It primarily consists of academic papers that present original empirical research and theoretical ...

Diversity

Invertebrates

Eggs laid by invertebrate animals are known from the fossil record. Among these are eggs laid by ancient

cephalopods A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

. Eggs laid by

are the best known cephalopod egg fossils. The best preserved fossil ammonite eggs were preserved in the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

Kimmeridge Clay The Kimmeridge Clay is a sedimentary rock, sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation (geology), form ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. Nevertheless, the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

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.

Fishes and amphibians

Fossil fish eggs have an extensive record going at least as far back as the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

and spanning into the

Cenozoic era The Cenozoic Era ( ; ) is Earth's current geological Era (geology), era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, Insect, insects, birds and flowering plant, angiosperms (floweri ...

. The eggs of many different fish

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

have contributed to this record, including

lobe-finned fish Sarcopterygii (; )—sometimes considered synonymous with Crossopterygii ()—is a clade (traditionally a class or subclass) of vertebrate animals which includes a group of bony fish commonly referred to as lobe-finned fish. These vertebrates ar ...

placoderms Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos plate' and δέρμα 'dermaskin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Dev ...

, and

sharks Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

. Occasionally eggs are preserved still within the mother's body, or associated with fossil

embryos An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

. Some fossil eggs possibly laid by fish cannot be confidently distinguished from those laid by

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

. Several fossilized fish or amphibian eggs have been classified as ichnogenera, including '' Mazonova'', '' Archaeoovulus'', '' Chimaerotheca'', ''

Fayolia ''Fayolia'' is a genus of fossil egg capsule, widely thought to have been produced by xenacanths. The egg is elongate and tapers towards both ends, and surrounded by helically twisted collarettes, with one end (the beak) having a tendril. It ...

'', and '' Vetacapsula''.

Reptiles

The fossil record of reptile eggs goes back at least as far as the

Early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

. However, since the earliest reptile eggs probably had soft shells with little

preservation potential Taphonomy is the study of how organisms decay and become fossilized or preserved in the paleontological record. The term ''taphonomy'' (from Greek , 'burial' and , 'law') was introduced to paleontology in 1940 by Soviet scientist Ivan Efremov ...

, reptilian eggs may go back significantly farther than their fossil record. Many ancient reptile groups are known from egg fossils including

crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

ns,

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s, and turtles. Some ancient reptiles, like ichthyosaursEllis, Richard, (2003) ''Sea Dragons - Predators of the Prehistoric Oceans''. University Press of Kansas. . and plesiosaurs are known to have given live birth and are therefore not anticipated to have left behind egg fossils.

Dinosaur eggs Dinosaur eggs are the organic vessels in which a dinosaur embryo develops. When the first scientifically documented remains of non-avian dinosaurs were being described in England during the 1820s, it was presumed that dinosaurs had laid eggs be ...

are among the most well known kind of fossil reptile eggs.

Classification

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).Olga Amo, Gloria Cuenca–Bescós & José Ignacio Canudo (1999). José Ignacio Canudo & Gloria Cuenca-Bescós, ed. "Vertebrate eggshell fragments from the Lower Cretaceous (Lower Barremian) of Camino Canales (Galve Bassin, Province of Teruel, NE Spain)" (PDF). IV European Workshop on Vertebrate Palaeontology. Albarracín, Spain: Universidad de Zaragoza. The names of oogenera and oofamilies conventionally contain the root "oolithus" meaning "stone egg", but this rule 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.Carpenter, Kenneth (1999). ''Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past)'', Indiana University Press; .

Parataxonomy

The oogenus level parataxonomy of Veterovata, following Lawver and Jackson (2014) for Testudoid, Hirsch (1996) for Geckonoid eggs, and Mikhailov et al. (1996) for the rest unless otherwise noted: Testudoid * ''Spheruflexibilis'' morphotype ** Oofamily

Testudoflexoolithidae ''Testudoflexoolithus'' is an oogenus of fossil turtle egg, containing two oospecies: ''T. bathonicae'' and ''T. agassizi''.Hirsch , K.F. (1996). "Parataxonomic Classification of Fossil Chelonian and Gecko Eggs." ''Journal of Vertebrate Paleontolo ...

*** '' Testudoflexoolithus'' * ''Spherurigidis'' morphotype ** Oofamily Testudoolithidae *** '' Testudoolithus'' *** '' Emydoolithus'' *** '' Haininchelys'' *** '' Chelonoolithus'' Geckoid * Geckonoid morphotype ** Oofamily

Gekkoolithidae ''Gekkoolithus'' is an oogenus of fossil gecko egg. Gecko eggs have not been well-studied, and their fossils are very rare, making classification of them difficult. ''Gekkolithus'' eggs are very similar to those of the modern '' Phelsuma delandis ...

*** ''

Gekkoolithus ''Gekkoolithus'' is an oogenus of fossil gecko egg. Gecko eggs have not been well-studied, and their fossils are very rare, making classification of them difficult. ''Gekkolithus'' eggs are very similar to those of the modern '' Phelsuma delandis ...

'' *** '' Gekkonidovum'' Crocodiloid * Oogenus

Mycomorphoolithus ''Mycomorphoolithus'' (meaning "fungus-shaped stone egg") is an oogenus of fossil eggs found in Spain and England. They possibly represent eggshells of non-eusuchian Crocodylomorpha, crocodylomorphs, and are similar to, but not part of, the Krokol ...

* Oofamily

Krokolithidae Krokolithidae is an oofamily of fossil crocodylomorph eggs. The oogenus ''Mycomorphoolithus ''Mycomorphoolithus'' (meaning "fungus-shaped stone egg") is an oogenus of fossil eggs found in Spain and England. They possibly represent eggshells of ...

** ''

Bauruoolithus ''Bauruoolithus'' is an oogenus of fossilized eggs belonging to an extinct crocodyliform from the Late Cretaceous ( late Campanian- early Maastrichtian) of Brazil. ''Bauruoolithus'' eggs were most likely laid by the notosuchian crocodyliform '' ...

'' ** ''

Krokolithes ''Krokolithes'' is an oogenus of Crocodiloid eggs. These eggs were laid by an extinct species of Crocodylian. It contains three oospecies: ''K. dinophilus'', ''K. wilsoni'' and ''K. helleri''. 1 Fossils of the oogenus have been found in the Oligo ...

'' ** ''

Suchoolithus ''Suchoolithus'' is an oogenus (fossil egg genus) of crocodylomorph eggs from the late Jurassic of Portugal. They are notable for their small size, and for being among the oldest known crocodylomorph eggs. Description ''Suchoolithus'' is known fr ...

'' Mosasauroid * '' Antarcticoolithus'' Dinosauroid-spherulitic * '' Placoolithus'' * '' Sphaerovum'' * ''

Stromatoolithus ''Stromatoolithus'' is an oogenus of dinosaur egg. The oogenus contains one oospecies, ''S. pinglingensis''. ''Stromatoolithus''at Fossilworks.org See also * List of dinosaur oogenera Egg fossils are the fossilized remains of eggs laid by a ...

'' * ''

Tacuarembovum ''Tacuarembovum'' (sometimes misspelled as "''Tacuaremborum''"; e.g.,)is an oogenus of fossil egg from the Late Cretaceous (Campanian to Maastrichtian) Asencio Formation of Uruguay.Mones, A. (1980) "Nuevos elementos de la paleoherpetofauna del Ur ...

'' * Oofamily

Cairanoolithidae ''Cairanoolithus'' is an oogenus of dinosaur egg which is found in Southwestern Europe. The eggs are large ( in diameter) and spherical. Their outer surface is either smooth, or covered with a subdued pattern of ridges interspersed with pits and ...

** ''

Cairanoolithus ''Cairanoolithus'' is an oogenus of dinosaur egg which is found in Southwestern Europe. The eggs are large ( in diameter) and spherical. Their outer surface is either smooth, or covered with a subdued pattern of ridges interspersed with pits and ...

''Sellés, A. G., & Galobart, À. (2015). Reassessing the endemic European Upper Cretaceous dinosaur egg Cairanoolithus. Historical Biology, (ahead-of-print), 1-14. * Oofamily

Stalicoolithidae Stalicoolithidae is an oofamily of fossil eggs.Wang Q, Wang X L, Zhao Z K, and Jiang Y G. (2012).A new oofamily of dinosaur egg from the Upper Cretaceous of Tiantai Basin, Zhejiang Province, and its mechanism of eggshell formation Chinese Science ...

** ''

Coralloidoolithus ''Coralloidoolithus'' is an oogenus of dinosaur egg from the Tiantai Basin in Zhejiang Province, containing a single known oospecies ''C. shizuiwanensis''. Formerly, it was classified in the oogenus ''Paraspheroolithus''; however, it was consider ...

'' ** ''

Shixingoolithus ''Shixingoolithus'' is an oogenus of dinosaur egg from the Cretaceous of Nanxiong, China.Z. Zhao, J. Ye, H. Li, Z. Zhao, and Z. Yan. 1991. Extinction of the dinosaurs across the Cretaceous-Tertiary boundary in Nanxiong Basin, Guangdong Province. ...

'' ** ''

Stalicoolithus ''Stalicoolithus'' is an oogenus of dinosaur egg from the Sanshui and Chichengshan Formations of the Tiantai Basin in Zhejiang Province. It is known from a single, complete fossil egg, notable for its spherical shape.Wang Q, Wang X L, Zhao Z K, ...

'' * Oofamily

Spheroolithidae Spheroolithidae is an oofamily of dinosaur eggs. It contains '' Guegoolithus'', '' Spheroolithus'', and '' Paraspheroolithus''. Like modern birds, the eggshell membrane formed before the calcareous Calcareous () is an adjective meaning "mostly ...

** ''

Guegoolithus ''Guegoolithus'' is an oogenus of fossil egg from the early Cretaceous of Spain. It is classified in the oofamily Spheroolithidae, and was probably laid by an ornithopod dinosaur. Distribution ''Guegoolithus'' is known from the Early Cretaceous ...

'' ** ''

Spheroolithus ''Spheroolithus'' is an oogenus of dinosaur egg.Wang Q, Wang X L, Zhao Z K, and Jiang Y G. (2012).A new oofamily of dinosaur egg from the Upper Cretaceous of Tiantai Basin, Zhejiang Province, and its mechanism of eggshell formation Chinese Scienc ...

'' ** ''

Paraspheroolithus ''Spheroolithus'' is an oogenus of dinosaur egg.Wang Q, Wang X L, Zhao Z K, and Jiang Y G. (2012).A new oofamily of dinosaur egg from the Upper Cretaceous of Tiantai Basin, Zhejiang Province, and its mechanism of eggshell formation Chinese Scienc ...

'' * Oofamily Phaceloolithidae ** '' Phaceloolithus'' * Oofamily Ovaloolithidae ** ''

Ovaloolithus ''Ovaloolithus'' is an oogenus of dinosaur egg. Eggs of the genus have been found in China, Mongolia and Utah. Species Oospecies attributed to this genus include:Megaloolithidae Megaloolithidae is an oofamily of fossil egg of the Dinosauroid-spherulitic morphotype. They probably are the eggs of sauropods. Paleopathology Multilayered shell Megaloolithid eggs with multiple layers of eggshell have been preserved in the f ...

** ''

Megaloolithus ''Megaloolithus'' is an oogenus of dinosaur egg. They are thought to have been laid by Sauropoda, sauropod dinosaurs. They are known for having thick eggshells, at least thick, and the nearly spherical shape of the eggs. They are primarily found ...

'' ** ''

Pseudomegaloolithus ''Pseudomegaloolithus'' is an oogenus of fossil Megaloolithid egg from Morocco. It is known from eggshell fragments which are distinguished from other Megaloolithid eggs because of its thin shells, fan-shaped eggshell units, and the structure of ...

'' * Oofamily

Similifaveoloolithidae ''Similifaveoloolithus'' is an oogenus of fossil dinosaur egg from the Tiantai basin in Zhejiang Province, China. It is the sole known oospecies of the oofamily Similifaveoloolithidae.Wang Qiang, Zhao Zikui, Wang Xiaolin, Zhang Shukang, and Jian ...

** ''

Similifaveoloolithus ''Similifaveoloolithus'' is an oogenus of fossil dinosaur egg from the Tiantai County, Tiantai basin in Zhejiang Province, China. It is the sole known oospecies of the oofamily Similifaveoloolithidae.Wang Qiang, Zhao Zikui, Wang Xiaolin, Zhang Sh ...

'' * Oofamily

Faveoloolithidae Faveoloolithidae is an oofamily of dinosaur eggs. It contains '' Faveoloolithus'', '' Hemifaveoloolithus'', '' Parafaveoloolithus'', and probably '' Sphaerovum''. However, unlike the other Faveoloolthids, ''Sphaerovum'' has compactituberculate ...

** ''

Faveoloolithus ''Faveoolithus'' is an oogenus of dinosaur egg. The oogenus contains two oospecies, ''F. ningxiaensis'' and ''F. zhangi''.Hemifaveoloolithus ''Hemifaveoloolithus'' is an oogenus of fossil dinosaur egg from the Tiantai basin in Zhejiang Province, China. It is a faveoloolithid, having spherical eggs roughly 13 cm in diameter. The shell is distinctive for being composed of four or ...

'' ** '' Parafaveoloolithus'' * Oofamily Youngoolithidae ** ''

Youngoolithus ''Youngoolithus'' is an oogenus of dinosaur egg.Carpenter, K. 1999. Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past). Indiana University Press, Bloomington, Indiana. It is the sole member of the oofamily Youngoo ...

'' * Oofamily

Dendroolithidae ''Dendroolithus'' is an oogenus of Dendroolithid dinosaur egg found in the late Cenomanian Chichengshan Formation ( Tiantai Group), in the Gong-An-Zhai and Santonian Majiacun Formations of China and the Maastrichtian Nemegt and Campanian B ...

** ''

Dendroolithus ''Dendroolithus'' is an oogenus of Dendroolithid dinosaur egg found in the late Cenomanian Chichengshan Formation ( Tiantai Group), in the Gong-An-Zhai and Santonian Majiacun Formations of China and the Maastrichtian Nemegt and Campanian B ...

'' * Oofamily

Dictyoolithidae Dictyoolithidae is an oofamily of dinosaur eggs which have a distinctive reticulate organization of their eggshell units. They are so far known only from Cretaceous formations in China. Distribution All known dictyoolithids are known from the Cr ...

** ''

Dictyoolithus ''Dictyoolithus'' is an oogenus of dinosaur egg from the Cretaceous of China. It is notable for having over five superimposed layers of eggshell units. Possibly, it was laid by megalosauroid dinosaurs. Distribution ''Dictyoolithus'' is known fro ...

'' ** '' Paradictyoolithus'' ** '' Protodictyoolithus'' * Oofamily Polyclonoolithidae ** ''

Polyclonoolithus ''Polyclonoolithus'' is an oogenus of fossil dinosaur egg. It is from the Early Cretaceous of Gansu, China. They have distinctive, branching eggshell units, which may represent the original form of Spheroolithidae, spheroolithids. Distribution ...

''Xie, J.-F., Zhang, S.-K., Jin, X.-S., Li, D.-Q., and Zhou, L.-Q. (2016)
A new type of dinosaur eggs from Early Cretaceous of Gansu Province, China.
" ''Vertebrata PalAsiatica'', 54(1):1-10. Dinosauroid-prismatic * '' Pseudogeckoolithus'' * Oofamily

Arriagadoolithidae Arriagadoolithidae is an oofamily of fossil eggs, representing the eggs of Alvarezsaurs. Description The eggs are well stratified with three layers: the external, the prismatic, and the mammillary. The connection between prismatic and external la ...

** ''

Arriagadoolithus ''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid ''Bonapartenykus''. Fossils of the creature were found in Patagonia; it may have brooded on its eggs. Description ''Arriagadoolithus patagoniensis'' i ...

'' ** ''

Triprismatoolithus ''Triprismatoolithus'' is an oogenus of dinosaur egg native to Teton County, Montana. It is classified in the oofamily Arriagadoolithidae, the eggs of alvarezsaurs. Distribution ''Triprismatoolithus'' is known exclusively from Sevenmile Hill, ...

'' * Oofamily

Prismatoolithidae Prismatoolithidae is an oofamily of fossil eggs. They may have been laid by ornithopods or theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') ...

** '' Preprismatoolithus'' ** ''

Prismatoolithus ''Prismatoolithus'' is an oogenus of dinosaur egg from the Cretaceous (Hauterivian-Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stag ...

'' ** ''

Protoceratopsidovum ''Protoceratopsidovum'' is an oogenus of dinosaur egg from Mongolia. Despite its name (which means "eggs of ''Protoceratops''"Zelenitsky, D., and Currie, P. (2004) "A Cladistic Analysis of Theropod Ootaxa." ''Journal of Vertebrate Paleontology.'' ...

'' ** ''

Sankofa (pronounced ''SAHN''-koh-fah) is a word in the Twi language of Ghana meaning “to retrieve" (literally "go back and get"; - to return; - to go; - to fetch, to seek and take) and also refers to the Bono people, Bono Adinkra symbols, Adinkra ...

'' ** '' Spheruprismatoolithus''E. S. Bray. 1999. Eggs and eggshell from the Upper Cretaceous North Horn Formation, central Utah. In D. D. Gillette (ed.), Vertebrate Paleontology in Utah, Utah Geological Survey Miscellaneous Publication 99-1:361-375 ** ''

Trigonoolithus ''Trigonoolithus'' is an oogenus of dinosaur egg, representing a basal prismatoolithid. Its eggshell, like avian eggs, is composed of three structural layers, but cladistic analysis suggests that its parent was a non-avian theropod. History Fossi ...

'' Ornithoid * Ornithoid-ratite Morphotype ** ''

Ageroolithus ''Ageroolithus'' is an oogenus of dinosaur egg. It may have been laid by a theropod. Distribution ''Ageroolithus'' fossils are found in the early Maastrichtian Tremp Basin of Lleida, Spain, from the Upper Cretaceous of France, and from the Lower ...

'' ** '' Diamantornis'' ** '' Ornitholithus'' ** '' Reticuloolithus''D. K. Zelenitsky and W. J. Sloboda. 2005. Eggshells. In P. J. Currie and E. B. Koppelhus (eds.), Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press, Bloomington 398-404 ** '' Struthiolithus'' ** '' Tristraguloolithus'' ** '' Tubercuoolithus'' ** Oofamily

Elongatoolithidae Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs (with the exception of the Bird, avian ''Ornitholithus''). They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia ...

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Continuoolithus ''Continuoolithus'' is an oogenus (fossil egg genus) of dinosaur egg found in the late Cretaceous of North America. It is most commonly known from the late Campanian of Alberta and Montana, but specimens have also been found dating to the older S ...

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Ellipsoolithus ''Ellipsoolithus'' is an oogenus of dinosaur egg. It contains only a single oospecies, ''E. khedaensis''. The species was found in the Upper Sandy Carbonate Member of the Lameta Formation of India. These eggs were probably laid by a theropod dino ...

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Elongatoolithus ''Elongatoolithus'' is an oogenus of dinosaur eggs found in the Late Cretaceous formations of China and Mongolia. Like other elongatoolithids, they were laid by small theropods (probably oviraptorosaurs), and were cared for and incubated by thei ...

*** ''

Heishanoolithus ''Heishanoolithus'' is an oogenus of Elongatoolithid fossil egg from the Shahai Formation in Liaoning ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, D ...

'' *** ''

Macroelongatoolithus ''Macroelongatoolithus'' is an oogenus of large theropod dinosaur eggs, representing the eggs of giant caenagnathid oviraptorosaurs. They are known from Asia and from North America. Historically, several oospecies have been assigned to ''Macroelo ...

'' *** ''

Macroolithus ''Macroolithus'' is an oogenus (fossil-egg genus) of dinosaur egg belonging to the oofamily Elongatoolithidae. The Type (biology), type oospecies, ''M. rugustus'', was originally described under the now-defunct oogenus name ''Oolithes''. Three o ...

'' *** '' Nanhsiungoolithus'' *** ''

Paraelongatoolithus ''Paraelongatoolithus'' is a late Cretaceous oogenus of Chinese fossil egg, classified in the oofamily Elongatoolithidae, which represents the eggs of oviraptorosaurs. Distribution ''Paraelongatoolithus'' is known solely from Chengguan, Tiantai ...

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Porituberoolithus ''Porituberoolithus'' is an oogenus of dinosaur egg found in the late Campanian Oldman Formation and Dinosaur Park Formation of Alberta, the Fossil Forest Member of the Fruitland Formation in New Mexico, the Upper Shale Member of the Aguja Format ...

'' *** '' Rodolphoolithus'' *** '' Spongioolithus'' *** '' Trachoolithus'' *** '' Undulatoolithus'' ** Oofamily

Laevisoolithidae Laevisoolithidae is an oofamily of fossil eggs belonging to the Ornithoid-ratite morphotype. Their eggshell An eggshell is the outer covering of a hard-shelled egg (biology), egg and of some forms of eggs with soft outer coats. Worm eggs ...

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Laevisoolithus ''Laevisoolithus'' is an oogenus of fossil egg. Its sole oospecies, ''L. sochavai,'' is native to the Nemegt Formation in Mongolia. ''Laevisoolithus'' is characterized by its thin, smooth eggshells. These eggs were probably laid by a bird or a s ...

'' *** ''

Subtiliolithus ''Subtiliolithus'' is an oogenus of fossil egg from the Nemegt Formation of Mongolia and the Ohyamashimo Formation of Japan. The eggs are notable for a very thin eggshell. It contains three oospecies: ''S. hyogoensis'', ''S. kachchhensis'' and ''S ...

'' *** ''

Tipoolithus ''Tipoolithus'' is an oogenus of fossil egg native to the Irbzer Formation in Morocco. Its classification is uncertain, but it most closely resembles Laevisoolithids, and like members of that oofamily, it was laid by an enantiornithine bird or ...

''Garcia, G., T. Rodolphe, H. Cappetta, B. Marandat, I. Bentaleb, A. Benabdallah and M. Vianey-Liaud. (2003). "First Record of Dinosaur Eggshels and Teeth from The North-West African Maastrichtian (Morocco)." ''Palaeovertebrata'', Montpellier, 32 (2-4): 59-69, ** Oofamily Medioolithidae *** '' Incognitoolithus'' *** ''

Microolithus ''Microolithus'' is an oogenus of fossil bird egg from Wyoming, with preserved embryonic remains inside some of its specimens. History Fossil bird eggs from the Paleogene are rare in North America, and have only occasionally been examined microst ...

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Mediolithus ''Medioolithus'' is an oogenus of fossil egg laid by a paleognath.Kohring, R., & Hirsch, K. F. (1996). "Crocodilian and avian eggshells from the Middle Eocene of the Geiseltal, Eastern Germany." ''Journal of Vertebrate Paleontology'', 16(1), 67-80 ...

'' ** Oofamily Montanoolithidae *** ''

Montanoolithus ''Montanoolithus'' is an oogenus of fossil egg found in Montana and Alberta. They were probably laid by a dromaeosaur or a caenagnathid.D. K. Zelenitsky and F. Therrien. (2008) "Unique maniraptoran egg clutch from the Upper Cretaceous Two Medicin ...

'' ** Oofamily Oblongoolithidae *** '' Oblongoolithus'' * Ornithoid-prismatic Morphotype ** ''

Dispersituberoolithus ''Dispersituberoolithus'' is an oogenus of fossil egg, which may have been laid by a bird or non-avian theropod.D. K. Zelenitsky, L. V. Hills, and P. J. Currie. (1996). Parataxonomic classification of ornithoid eggshell fragments from the Oldman F ...

'' ** Oofamily Gobioolithidae *** ''

Gobioolithus ''Gobioolithus'' is an oogenus of fossil bird egg native to Mongolia. They are small, smooth-shelled, and elongated eggs that were first discovered in the 1960s and early 70s during a series of fossil-hunting expeditions in the Gobi Desert. Two ...

'' ''

Incertae sedis or is a term used for a taxonomy (biology), 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 ...

/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 a communication to the 4 May 1859 mee ...

'' * '' Metoolithus'' * ''

Mosaicoolithus ''Mosaicoolithus'' is an oogenus of fossil egg from the Cenomanian Chichengshan Formation (Tiantai Group) and Albian to Cenomanian Laijia Formation (Qujiang Group) of Tiantai County, Zhejiang Province in China. Its classification is incertae sed ...

'' * ''

'' * '' Nipponoolithus'' * ''

Parvoblongoolithus ''Parvoblongoolithus'' is an oogenus of fossil dinosaur egg whose small size and unusual shape suggest the possibility that it is a dwarf egg. Distribution The sole known ''Parvoblongoolithus jinguoensis'' specimen was found in the Upper Cretace ...

'' * ''

Parvoolithus ''Parvoolithus'' is an oogenus of Mongolian fossil eggs from the Campanian Barun Goyot Formation. They are known from a single small, smooth egg, which cannot be assigned to any known oofamily. It is very similar to the eggs of modern birds in ma ...

''Mikhailov, K.E. (1997). Fossil and recent eggshell in amniotic vertebrates: Fine structure, comparative morphology and classification. Special Papers in Palaeontology 56. The Palaeontological Association. London. (page 58). * '' Plagioolithus'' * '' Styloolithus'' * Oofamily

Pachycorioolithidae ''Pachycorioolithus'' is an oogenus of small, thin-shelled fossil egg from the early Cretaceous in China. It probably belongs to a bird, though there is a possibility the parent was a non-avian theropod. It was named in 2016, based on a single spe ...

** '' Pachycorioolithus''

References

External links

UCMP's online fossil egg exhibit

Paleofile
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