''Quasipetalichthys haikouensis'' is the type and only known species of the extinct petalichthid

placoderm Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos'''Plate (animal anatomy), plate' and δέρμα 'derma'''skin') are vertebrate animals of the class (biology), class Placodermi, an extinct group of prehistoric fish known from Pal ...

, ''Quasipetalichthys''. Fossil remains of ''Quasipetalichthys'' have been found in the Middle

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 ...

, Givetian

faunal stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by conven ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Fossils

''Quasipetalichthys'' is known primarily from two poorly preserved skulls from the Givetian-aged Haikou Formation of

Haikou Haikou; Chinese postal romanization, formerly romanized as Hoihow is the capital city, capital and most populous city of the Chinese province of Hainan. Haikou city is situated on the northern coast of Hainan, by the mouth of the Nandu River. ...

Kunming Kunming is the capital and largest city of the province of Yunnan in China. The political, economic, communications and cultural centre of the province, Kunming is also the seat of the provincial government. During World War II, Kunming was a Ch ...

, where they were found in association with remains of antiarch placoderms such as '' Bothriolepis sinensis'', and '' Hunanolepis''. The larger of the two skulls may have been around in length.

Phylogeny

''Quasipetalichthys haikouensis'' is considered a basal petalichthyid (though in 1978 Denison referred to it as being "aberrant"). In Zhu's 1991 redescription of ''Diandongpetalichthys'',Zhu, M. "New information on ''Diandongpetalichthys'' (Placodermi: Petalichthyida)." Early vertebrates and related problems of evolutionary biology. Science Press, Beijing (1991): 179-192. ''Quasipetalichthys'' was placed within a different family: the Quasipetalichthyidae, and was regarded as the sister group of the more advanced Macropetalichthyidae, with ''Diandongpetalichthys'' serving as the primitive sister group of these two taxa. ''

Neopetalichthys ''Neopetalichthys yenmenpaensis'' is an extinct petalichthid placoderm from the Early Devonian of China. Fossils The holotype and only known specimen is a poorly preserved partial, and elongated skull from Emsian-aged strata in Sichuan. The s ...

'' may be very closely related to ''Quasipetalichthys'', and may or may not be placed together within Quasipetalichthyidae in a more completed phylogeny. Whether or not ''Neopetalichthys'' is included in the family, '' Eurycaraspis'' is placed in Quasipetalichthyidae as a sister taxon to''Quasipetalichthys''.

Distribution and habitat

The Haikou Formation, the only known set of rocks that has produced fossils of ''Quasipetalichthys'', appears at the Earth's surface in south-central China.L. Gao. 1981. Devonian Spore Assemblages of China. Review of Paleobotany and Palynology. 34:11-23 Other paleontological investigations into these sediments have produced spores and macrofossils from Devonian plants such as the

Lycopods Lycopodiopsida is a class of vascular plants also known as lycopsids, lycopods, or lycophytes. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves ...

(classified as Lycopodophyta or Lycopsida)). C. S. Li. 1990. Minarodendron cathaysiense (gen. et comb. nov.), A lycopod from the late Middle Devonian of Yunnan, China. Palaeontographica Abteilung B. 220:97-117S. Hao, J. Xue, and Q. Wang, Z. Liu. 2007. Yuguangia ordinata gen. et sp. nov., a New Lycopsid from the Middle Devonian (Late Givetian) of Yunnan, China, and Its Phylogenetic Implications. International Journal of Plant Sciences. 168(8):1161-1175 These plant remains often occur alongside those of Placoderms such as ''Bothriolepis'' which implies a very near-shore or freshwater environment for this geologic formation.

References

External links

''Quasipetalichthys''
at the

Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

{{Taxonbar, from=Q7269517 Fossil taxa described in 1973 Placoderms of Asia Placoderm genera Petalichthyida