Yunnanolepididae

Yunnanolepididae; Temporal range: Early to Middle Devonian
	Yunnanolepis chii and Mizia parvus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Antiarchi
Family:	†Yunnanolepididae
Type species
	Yunnanolepis chii; Liu, 1963
Genera
	Yunnanolepis Liu, 1963; Parayunnanolepis Tong-Dzuy & Janvier 1990; Mizia Thanh & Janvier 1994; Phymolepis Zhang Guorui 1978; Vukhuclepis Janvier, Thanh, Phuong & Truong 1997;

Yunnanolepididae is an extinct family of primitive Antiarch placoderms characterized by having short, broad skull roofs, and by having a feature on the visceral side of the posterior medial dorsal plate, the crista transversalis interna posterior, which is diagnostic of antiarchs, turning forward, and lying in front of the posterior ventral process and pit (with this position being diagnostic of yunnanolepids in particular).

At least three genera, Yunnanolepis, Phymolepis, and Vukhuclepis are confirmed to have a unique organ called the "Chang's Apparatus," named in honor of Professor Meemann Chang, which is an internal cavity with an external opening within the suture of the anterior dorsal lateral plate and the anterior ventral lateral plate. The other genera in Yunnanolepidae that are not confirmed to have the Chang's Apparatus are included in the family because of anatomical similarities to Yunnanolepis.

The fossils of the various genera are found in Early to Middle Devonian strata in Southern China and Middle Devonian strata in Vietnam.

References

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.