Spalacotheriidae is a family of extinct mammals belonging to the
paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
group '
Symmetrodonta
Symmetrodonta is a group of Mesozoic mammals and mammal-like synapsids characterized by the triangular aspect of the molars when viewed from above, and the absence of a well-developed talonid. The traditional group of 'symmetrodonts' ranges in ...
'. They lasted from the
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
to the
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...
in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
,
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
,
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
and
North Africa
North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...
.
Spalacotheriids are characterised by having molar teeth with three molar cusps sitting at acute angles to one another.Martin, T., 2018. 6. Mesozoic mammals—early mammalian diversity and ecomorphological adaptations. In Mammalian evolution, diversity and systematics (pp. 199-300). De Gruyter. The shape of their teeth as well as their long lower jaw indicate a
carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
/
insectivorous
A robber fly eating a hoverfly
An insectivore is a carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects.
The first vertebrate insectivores we ...
diet.
A sub-group of Spalacotheriidae, the spalacolestines, lack a
Meckelian groove
The Meckelian groove (or Meckel's groove, Meckelian fossa, or Meckelian foramen, or Meckelian canal) is an opening in the medial (inner) surface of the mandible (lower jaw) which exposes the Meckelian cartilage.modern ear anatomy.
Genera
* ''
Akidolestes
''Akidolestes'' is an extinct genus of mammals of the family Spalacotheriidae, a group of mammals related to therians (the subclass containing marsupials and placentals).
The genus name, ''Akidolestes'', is derived from ''akido'', Greek for p ...
''
* ''
Infernolestes
''Infernolestes'' is an extinct genus of spalacotheriid that lived during the Early Cretaceous epoch.
Distribution
''Infernolestes rougieri'' is known from the Lakota Formation of the United States
The United States of America (USA), al ...
''
* ''
Spalacotherium
''Spalacotherium'' is a genus of extinct mammal from the Early Cretaceous of Europe. The type species ''Spalacotherium tricuspidens'' was originally named by Richard Owen in 1854, and its material includes maxillary and dentary fragments and many ...
''
* ''
Symmetrolestes
''Symmetrolestes'' is an extinct genus of small spalacotheriid mammal from the Early Cretaceous period of Japan. The genus contains one species known as ''S. parvus'', the type fossil (which is only fossil known) is from fluvial deposits located ...
Yaverlestes
''Yaverlestes gassoni'' is an extinct mammal which dates to the early Cretaceous period, 130 million years ago. It is part of the Wessex Formation from the Isle of Wight, England. The holotype
A holotype (Latin: ''holotypus'') is a single ...