[PaleoMammalogy • 2015]
Spinolestes xenarthrosus
A Cretaceous Eutriconodont and Integument Evolution in Early Mammals
 |
| Spinolestes xenarthrosus
Martin, Marugán-Lobón, Vullo, Martín-Abad, Luo & Buscalioni, 2015
doi: 10.1038/nature14905 life reconstruction in its natural environment of the Las Hoyas wetland.
Illustration: Oscar Sanisidro
|
The Mesozoic era (252–66 million years ago), known as the domain of
dinosaurs, witnessed a remarkable ecomorphological diversity of early
mammals. The key mammalian characteristics originated during this period
and were prerequisite for their evolutionary success after extinction
of the non-avian dinosaurs 66 million years ago. Many ecomorphotypes
familiar to modern mammal fauna evolved independently early in mammalian
evolutionary history.
Here we report a 125-million-year-old
eutriconodontan mammal from Spain with extraordinary preservation of
skin and pelage that extends the record of key mammalian integumentary
features into the Mesozoic era. The new mammalian specimen exhibits such
typical mammalian features as pelage, mane, pinna, and a variety of
skin structures: keratinous dermal scutes, protospines composed of
hair-like tubules, and compound follicles with primary and secondary
hairs. The skin structures of this new Mesozoic mammal encompass the
same combination of integumentary features as those evolved
independently in other crown Mammalia, with similarly broad structural
variations as in extant mammals. Soft tissues in the thorax and abdomen
(alveolar lungs and liver) suggest the presence of a muscular diaphragm.
The eutriconodont has molariform tooth replacement, ossified Meckel’s
cartilage of the middle ear, and specialized xenarthrous articulations
of posterior dorsal vertebrae, convergent with extant xenarthran
mammals, which strengthened the vertebral column for locomotion.
Class Mammalia
Order Eutriconodonta
Family Gobiconodontidae
Spinolestes xenarthrosus gen. et sp. nov.
Etymology. Spinosus (Latin), in reference to the spiny integument; λέστης (Greek) or lestes (Latin spelling), meaning robber and a common term in taxonomic names of mammals. The specific name xenarthrosus refers
to the special additional (ξένος, (Greek) strange) articulation facets
(ἄρϑρον, (Greek) articulation) of the dorsal vertebrae.
Locality and horizon. Las Hoyas Quarry, Calizas de la Huérgina
Formation, southwestern Iberian Basin (Cuenca, Spain). Las Hoyas is
latest Barremian (125–127 Ma) in age, on the basis of charophytes and
ostracodes17. The Las Hoyas Konservat-Lagerstätte occurs in finely
laminated limestones deriving from a freshwater wetland. Fossils are
usually preserved fully articulated, including soft tissues such as
mineralized muscle and skin. Potential mechanisms for exquisite
preservation are microbial mats, anoxia, and rapid burial by
sediments18.
Thomas Martin, Jesús Marugán-Lobón, Romain Vullo, Hugo Martín-Abad,
Zhe-Xi Luo and Angela D. Buscalioni. 2015. A Cretaceous Eutriconodont
and Integument Evolution in Early Mammals.
Nature. 526, 380–384. doi: 10.1038/nature14905
Nature. 526, 380–384. doi: 10.1038/nature14905
125-million-year-old mammal fossil preserved with hair, spines and even a fungal infection http://t.co/lr0RfD3h8o via @ScienceLife
Nenhum comentário:
Postar um comentário
Observação: somente um membro deste blog pode postar um comentário.