[dinosaur] Origolestes, new symmetrodont mammal from Early Cretaceous of China

Ben Creisler
[email protected]

A new paper:

Origolestes lii gen. et sp. nov.

Fangyuan Mao, Yaoming Hu, Chuankui Li, Yuanqing Wang, Morgan Hill Chase,
Andrew K. Smith & Jin Meng (2019)
Integrated hearing and chewing modules decoupled in a Cretaceous stem
therian mammal.
Science: eaay9220 (advance online publication)
DOI: 10.1126/science.aay9220
https://urldefense.proofpoint.com/v2/url?u=https-3A__science.sciencemag.org_content_early_2019_12_04_science.aay9220&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=j_aJ1JEdFVSbVmuVzMsNA5vPm2DvVgK5S5bOwibp2k4&s=8wj5_urg5iyUtek-LZOGcNSo-I9xfUiu-QzDfE2qd3I&e= 



Based on multiple 3D skeletal specimens we report a new Cretaceous stem
therian mammal that displays decoupling of hearing and chewing apparatuses
and functions. The auditory bones, including the surangular, have no bone
contact with the ossified Meckel’s cartilage; the latter is loosely lodged
on the medial rear of the dentary. This configuration probably represents
the initial morphological stage of the definitive mammalian middle ear.
Evidence shows that hearing and chewing apparatuses have evolved in a
modular fashion. Starting as an integrated complex in non-mammaliaform
cynodonts, the two modules, regulated by similar developmental and genetic
mechanisms, eventually decoupled during the evolution of mammals, allowing
further improvement for more efficient hearing and mastication.

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