Definition

1. Noun:
   • A taxonomic order of extinct reptiles: "Order Therapsida" refers to a specific scientific classification of extinct animals that were reptile-like but displayed many mammalian characteristics. These creatures lived on all continents during a specific geological time period, from the middle Permian epoch to the late Triassic epoch.

Usage Examples

• Noun:
  • Fossil evidence suggests that Order Therapsida includes the ancestors of modern mammals.
  • The transition from reptile to mammal is studied through specimens from Order Therapsida.

Advanced Usage

• In paleontological context: The term is used precisely to denote this clade within scientific literature and discussion.
  • The phylogenetic tree shows Order Therapsida as a sister group to what would become true mammals.

Variants and Related Words

• Therapsid (n): A member of the Order Therapsida.
  • The dicynodont is a well-known type of therapsid.
• Synapsid (n): A broader taxonomic group that includes therapsids and their ancestors.
  • Pelycosaurs are early synapsids that preceded the therapsids.

Synonyms

• Mammal-like reptiles: A descriptive, non-taxonomic synonym often used in general science communication.

Related Phrases

• Therapsid fauna: Refers to the collective animal life dominated by members of this order during its time.
  • The therapsid fauna of the Permian period was diverse.

Related Terminology

• Cynodonts (n): An advanced subgroup within Order Therapsida that are very close to the mammalian lineage.
  • Cynodonts, a subgroup of Order Therapsida, had jaw bones that began to resemble the mammalian ear.

Noun

1. extinct mammal-like reptiles found inhabiting all continents from the mid Permian to late Triassic