The Aptian extinction was an

extinction event An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...

of the early

Cretaceous Period The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of t ...

. It is dated to c. 116 or 117 million years ago, in the middle of the

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ag ...

stage of the

geological time scale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochro ...

, and has sometimes been termed the mid-Aptian extinction event as a result. It is classified as a minor extinction event, rather than a major event like the famous

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...

that brought about the end of the "age of dinosaurs" and the

Mesozoic Era The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

. The Aptian event is most readily detected among marine rather than terrestrial fossil deposits. Nonetheless, "From a palaeobotanical perspective, the Aptian Extinction Event is an episode of importance, deserving a higher status among other minor events." The Aptian event may have been causally connected with the

Rahjamal Traps The Rajmahal Traps is a volcanic igneous province in Eastern India, covering the parts of Jharkhand, West Bengal and Meghalaya. The Rajmahal Hills of Jharkhand is the type area of this province. Multiple layers of solidified lava made the Rajma ...

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

episode in the Bengal region of India, associated with the

Kerguelen hotspot The Kerguelen hotspot is a volcanic hotspot at the Kerguelen Plateau in the Southern Indian Ocean. The Kerguelen hotspot has produced basaltic lava for about 130 million years and has also produced the Kerguelen Islands, Naturaliste Plateau, Hea ...

of volcanic activity. Courtillot, Vincent. ''Evolutionary Catastrophes: The Science of Mass Extinctions.'' Cambridge, Cambridge University Press, 1999; p. 95. (At the time in question, c. 116–117 Ma, India was located in the southern Indian Ocean; plate tectonics had not yet moved the Indian landmass into its present position.) Note that the

stegosaur Stegosauria is a group of herbivorous ornithischian dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaurian fossils have been found mostly in the Northern Hemisphere, predominantly in what is now North America, Euro ...

group of

dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the ...

went extinct around this time. ''

Wuerhosaurus ''Wuerhosaurus'' is a genus of stegosaurid dinosaur from the Early Cretaceous Period of western China and Inner Mongolia. As such, it was one of the last genera of stegosaurians known to have existed, since most others lived in the late Jurassic ...

'', probably the last of the stegosaurs, lived during this time. The

tritylodont Tritylodontidae ("three-knob teeth", named after the shape of their cheek teeth) is an extinct family of small to medium-sized, highly specialized mammal-like cynodonts, bearing several mammalian traits like erect limbs, endothermy and details o ...

s, the last surviving relatives (but not members) of the

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...

went extinct around this time too. These extinctions may be associated with this event.

References

{{ExtEvent_nav Early Cretaceous extinctions Extinction events Aptian