Thursday, August 10, 2017

[PaleoMammalogy • 2017] Maiopatagium furculiferum • A New Gliding Mammaliaforms from the Jurassic of China

Maiopatagium furculiferum 
Meng, Grossnickle, Liu, Zhang, Neander, Ji & Luo, 2017 

Reconstruction by April I. Neander | DOI: 10.1038/nature23476 

Stem mammaliaforms are Mesozoic forerunners to mammals, and they offer critical evidence for the anatomical evolution and ecological diversification during the earliest mammalian history. Two new eleutherodonts from the Late Jurassic period have skin membranes and skeletal features that are adapted for gliding. Characteristics of their digits provide evidence of roosting behaviour, as in dermopterans and bats, and their feet have a calcaneal calcar to support the uropagatium as in bats. The new volant taxa are phylogenetically nested with arboreal eleutherodonts. Together, they show an evolutionary experimentation similar to the iterative evolutions of gliders within arboreal groups of marsupial and placental mammals. However, gliding eleutherodonts possess rigid interclavicle–clavicle structures, convergent to the avian furculum, and they retain shoulder girdle plesiomorphies of mammaliaforms and monotremes. Forelimb mobility required by gliding occurs at the acromion–clavicle and glenohumeral joints, is different from and convergent to the shoulder mobility at the pivotal clavicle–sternal joint in marsupial and placental gliders.

Clade Mammaliaformes
Clade Haramiyida 

Clade (Order) Eleutherodontida

Maiopatagium furculiferum gen. et sp. nov.

Etymology: Maio (Latin): mother; patagium (Latin): skin membrane, referring to the preserved patagial membranes of the fossil; furcula (Latin): fork; ferum (Latin): similar, in reference to the sutured and/or fused interclavicle and clavicles that are morphologically convergent to the furculum (wishbone) of birds.

Locality and geologic age: The Daxishan fossil site of Linglongta township, Jianchang County, Liaoning Province, China. The fossil slab has preserved specimens of the index fossil Qaidamestheria sp. (Euestheria luanpingensis) that are known from the upper fossiliferous stratigraphic level of the Tiaojishan Formation. The vertebrate-bearing level of this site is dated to be 158.5 ± 1.6 to 161.0 ± 1.44 million years old. The Tiaojishan fauna has yielded several additional mammaliaforms.

fossil of gliding mammaliaform Maiopatagium furculiferum (type specimen from Beijing Museum of Natural History BMNH 2940).
photo: Zhe-Xi Luo 

Maiopatagium in Jurassic forest in crepuscular (dawn and dusk) light: A mother with a baby in suspending roosting posture, climbing on tree trunk, and in gliding
 Reconstruction by April I. Neander 

Qing-Jin Meng, David M. Grossnickle, Di Liu, Yu-Guang Zhang, April I. Neander, Qiang Ji & Zhe-Xi Luo. 2017. New Gliding Mammaliaforms from the Jurassic. Nature. DOI: 10.1038/nature23476
Researchers discover first winged mammals from the Jurassic period via @physorg_com
Rare Fossils Reveal New Species of Ancient Gliding Mammals via @NatGeo