| Phaceloolithus Temporal range: | |
|---|---|
Egg fossil classification  | |
| Basic shell type: | † Dinosauroid-spherulitic |
| Oofamily: | † Phaceloolithidae Zeng & Zhang, 1979 |
| Oogenus: | † Phaceloolithus Zeng & Zhang, 1979 |
| Oospecies | |
Phaceloolithus is an oogenus of dinosaur egg found in the Fenshui'ao Formation of the Dongting Basin of the Hunan Province of China. The eggs have a subspherical shape, measuring up to 168 mm on the long axis, and having a very thin shell. [1] [2]
Phaceloolithus is found at the Dongting Basin in Hunan. They are dated, on the basis of other fossil eggs, ostracods (seed shrimp), and charophytes (algae) found at the same site, to the late Cretaceous. [1]
Phaceloolithus is nearly spherical, measuring 167–168 mm long and 140–150 mm across. The eggshell is very thin, measuring from 0.5 to 0.7 mm thick. [1] Like most other non-avian dinosaur eggs, [3] Phaceloolithus's shell is stratified into two layers: the prismatic layer on the outside, and the mammillary layer on the inside. [1] The mammillae are compressed into groups of two or three, and the pore canals are well-developed. [1]
Phaceloolithus was first described as the sole species of the oofamily Phaceloolithidae in 1979 by Chinese paleontologists Zeng Demin and Zhang Jinjian, following its discovery in the Dongting basin of Hunan. [1]
While Phaceloolithus has always been considered an oospecies of Phaceloolithidae, there is dispute about whether or not this oofamily is synonymous with the later-named Dendroolithidae. The oofamilies were first synonymized by Fang et al. in 2003. [4] This position was supported by Ribeiro et al. in 2014, [5] but other authors have considered the two oofamilies distinct, [6] [7] and in his master's thesis, Daniel Barta argued against synonymy because the brevity of the description of Phaceloolithidae makes any further referrals to that oofamily uncertain. [8] If the synonymy is correct, then Phaceloolithus would be a sister taxon to Dendroolithus and Paradendroolithus . If not, then Phaceloolithus would be the sole oogenus of Phaceloolithus. [9]
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, and were cared for and incubated by their parents until hatching. They are often found in nests arranged in multiple layers of concentric rings. As its name suggests, Elongatoolithus was a highly elongated form of egg. It is historically significant for being among the first fossil eggs given a parataxonomic name.
Dendroolithus is an oogenus of Dendroolithid dinosaur egg found in the late Cenomanian Chichengshan Formation, in the Gong-An-Zhai and Santonian Majiacun Formations of China and the Maastrichtian Nemegt and Campanian Barun Goyot Formation of Mongolia. They can be up to 162 mm long and 130 mm wide. These eggs may have been laid by a Therizinosaur, Sauropod, or Ornithopod. The oospecies "D." shangtangensis was originally classified as Dendroolithus, however, it has since been moved to its own distinct oogenus, Similifaveoloolithus. This oogenus is related with embryos of the theropod Torvosaurus
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.
Shixingoolithus is an oogenus of dinosaur egg from the Cretaceous of Nanxiong, China.
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 Macroelongatoolithus, however they are all now considered to be a single oospecies: M. carlylensis.
Macroolithus is an oogenus of dinosaur egg belonging to the oofamily Elongatoolithidae. The type oospecies, M. rugustus, was originally described under the now-defunct oogenus name Oolithes. Three other oospecies are known: M. yaotunensis, M. mutabilis, and M. lashuyuanensis. They are relatively large, elongated eggs with a two-layered eggshell. Their nests consist of large, concentric rings of paired eggs. There is evidence of blue-green pigmentation in its shell, which may have helped camouflage the nests.
Ageroolithus is an oogenus of dinosaur egg. It may have been laid by a theropod.
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.
Paraelongatoolithus is a late Cretaceous oogenus of Chinese fossil egg, classified in the oofamily Elongatoolithidae, which represents the eggs of oviraptorosaurs.
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.
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 considered sufficiently different to be classified in its own genus. C. shizuiwanensis is similar to Stalicoolithus, leading to their classification in the same family, Stalicoolithidae.
Parvoblongoolithus is an oogenus of fossil dinosaur egg whose small size and unusual shape suggest the possibility that it is a dwarf egg.
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.
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 five superimposed layers of shell units, and the honeycomb-like arrangement of pore canals.
Parafaveoloolithus is an oogenus of Faveoloolithid fossil egg, known from the Cretaceous of China.
Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs. They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia, and both North and South America.
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 spheroolithids.
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.
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 specimen found in Zhejiang.
Nanhsiungoolithus is an oogenus of dinosaur egg from the late Cretaceous of China. It belongs to the oofamily Elongatoolithidae, which means that it was probably laid by an oviraptorosaur, though so far no skeletal remains have been discovered in association with Nanhsiungoolithus. The oogenus contains only a single described oospecies, N. chuetienensis. It is fairly rare, only being know from two partially preserved nests and a few eggshell fragments.
