''Phaceloolithus'' is an
oogenus of
dinosaur egg found in the
Fenshui'ao Formation of the
Dongting
Dongting Lake () is a large, shallow lake in northeastern Hunan Province, China. It is a flood basin of the Yangtze River, so its volume depends on the season. The provinces of Hubei and Hunan are named after their location relative to the la ...
Basin of the
Hunan Province
Hunan (, ; ) is a landlocked province of the People's Republic of China, part of the South Central China region. Located in the middle reaches of the Yangtze watershed, it borders the province-level divisions of Hubei to the north, Jiangxi t ...
of
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
. The eggs have a subspherical shape, measuring up to 168 mm on the long axis, and having a very thin shell.
[D. Zeng and J. Zhang. (1979).]
On the dinosaurian eggs from the western Dongting Basin, Hunan
. ''Vertebrata PalAsiatica'' 17(2):131–136[Carpenter, K. (1999). ''Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction'' (Life of the Past). Indiana University Press, Bloomington, Indiana.]
Distribution
''Phaceloolithus'' is found at the Dongting Basin in Hunan. They are dated, on the basis of other fossil eggs,
ostracods
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typical ...
(seed shrimp), and
charophytes
Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a phylum, division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly fro ...
(algae) found at the same site, to the
late Cretaceous.
Description
''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.
Like most other non-
avian
Avian may refer to:
*Birds or Aves, winged animals
*Avian (given name) (russian: Авиа́н, link=no), a male forename
Aviation
*Avro Avian, a series of light aircraft made by Avro in the 1920s and 1930s
*Avian Limited, a hang glider manufacture ...
dinosaur eggs,
[Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. Bray. (2012).]
Fossil eggshell: Fragments from the past
UCMP's online fossil egg exhibit. ''Phaceloolithuss shell is stratified into two layers: the prismatic layer on the outside, and the mammillary layer on the inside.
The mammillae are compressed into groups of two or three, and the pore canals are well-developed.
History
''Phaceloolithus'' was first described as the sole species of the oofamily Phaceloolithidae in
1979
Events
January
* January 1
** United Nations Secretary-General Kurt Waldheim heralds the start of the ''International Year of the Child''. Many musicians donate to the ''Music for UNICEF Concert'' fund, among them ABBA, who write the song ...
by Chinese paleontologists Zeng Demin and Zhang Jinjian, following its discovery in the Dongting basin of
Hunan.
Parataxonomy
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
File:2003 Events Collage.png, From top left, clockwise: The crew of STS-107 perished when the Space Shuttle Columbia disintegrated during reentry into Earth's atmosphere; SARS became an epidemic in China, and was a precursor to SARS-CoV-2; A des ...
.
[Fang, Xiao-si, et al. "Cretaceous fossil eggs from the Tiantai basin of Zhejiang, with a discussion on the extinction of dinosaurs." ''Geological Bulletin of China'' 22.7 (2003): 1–24.] This position was supported by Ribeiro ''et al.'' in
2014
File:2014 Events Collage.png, From top left, clockwise: Stocking up supplies and personal protective equipment (PPE) for the Western African Ebola virus epidemic; Citizens examining the ruins after the Chibok schoolgirls kidnapping; Bundles of wat ...
,
[Ribeiro, V., Mateus, O., Holwerda, F., Araújo, R., & Castanhinha, R. (2014). "Two new theropod egg sites from the Late Jurassic Lourinhã Formation, Portugal." ''Historical Biology'', 26(2), 206–217.] but other authors have considered the two oofamilies distinct,
[Barta, D. E., Brundridge, K. M., Croghan, J. A., Jackson, F. D., Varricchio, D. J., Jin, X., & Poust, A. W. (2014). "Eggs and clutches of the Spheroolithidae from the Cretaceous Tiantai basin, Zhejiang Province, China." ''Historical Biology'', 26(2), 183–194.] 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.
[Barta, D. E. (2014). "A phylogenetic approach to understanding dinosaur egg diversity and the evolution of reproductive traits within Dinosauria" (Master's thesis, Montana State University-Bozeman, College of Letters & Science).] If the synonymy is correct, then ''Phaceloolithus'' would be a sister taxon to ''
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 Bar ...
'' and ''
Paradendroolithus''. If not, then ''Phaceloolithus'' would be the
sole oogenus of Phaceloolithus.
[Fang Xiao-si, Yue Zhao, Ling Hong. (2009). "近十五年来蛋化石研究概况 eview of the Past 15 years’ Research on Fossil Eggs in China. 地球学报, 30(4), 523–542.]
See also
*
List of dinosaur oogenera
References
{{Taxonbar, from=Q7179941
Dinosaur reproduction
Fossil parataxa described in 1979