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Compared to many other ostracoderms, such as the Heterostraci and Osteostraci, anaspids did not possess a bony shield or armor, hence their name.The anaspid head and body are instead covered in an array of small, weakly mineralized scales, with a row of massive scutes running down the back, and, at least confirmed among the birkeniids, the body was covered in rows of tile-like scales made of ...
Testudines (Turtles, tortoises & terrapins) An anapsid is an amniote whose skull lacks one or more skull openings (fenestra, or fossae) near the temples . [ 1 ] Traditionally, the Anapsida are considered the most primitive subclass of amniotes, the ancestral stock from which Synapsida and Diapsida evolved, making anapsids paraphyletic .
A = Anapsid, B = Synapsid, C = Diapsid. It was traditionally assumed that first reptiles were anapsids, having a solid skull with holes only for the nose, eyes, spinal cord, etc.; [10] the discoveries of synapsid-like openings in the skull roof of the skulls of several members of Parareptilia, including lanthanosuchoids, millerettids, bolosaurids, some nycteroleterids, some procolophonoids and ...
Pantestudines or Pan-Testudines is the proposed group of all reptiles more closely related to turtles than to any other living animal. It includes both modern turtles (crown group turtles, also known as Testudines) and all of their extinct relatives (also known as stem-turtles). [2] Pantestudines with a complete shell are placed in the clade ...
They are commonly and collectively known as the Tasmanian anaspid crustaceans. [2] This family is originally called as Anaspididae. However, genus name Anaspis was preoccupied by the insect genus, Anaspis Geoffroy, 1762, [3] and therefore, in 2017, the family was renamed to Anaspidesidae by Shane Ahyong and Miguel A. Alonso-Zarazaga. [3] [4]
"Labyrinthodontia" (Greek, 'maze-toothed') is an informal grouping of extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras (about 390 to 150 million years ago).
They are commonly and collectively known as the Tasmanian anaspid crustaceans. [2] Anaspidids have stalked eyes, long antennae and antennules, and a slender body with no carapace. The two species of Allanaspides [3] [4] and the single species of Paranaspides [5] are all listed as vulnerable on the IUCN Red List.
Euryapsids are usually considered entirely extinct, although turtles might be part of the sauropterygian clade [1] while other authors disagree. [2] Euryapsida may also be a synonym of Sauropterygia sensu lato. [3] The ichthyosaurian skull is sometimes described as having a metapsid (or parapsid) condition instead of a truly euryapsid one.