''Microsphenodon'' is an
extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
sphenodontian
Rhynchocephalia (; ) is an order (biology), order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians ...
from the
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...
of
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. The type species is ''Microsphenodon bonapartei''.
It is a small sphenodontian with a skull roughly 20 mm long, and represents a unique mosaic of characteristics shared by both early diverging sphenodontians (such as a broad parietal table, multiple tooth rows on the palate, and an elongated premaxillary process) and eusphenodontian characters (full acrodont dentition, high coronoid process and anterior successional teeth, including the earliest known caniniforms in a lepidosaur). Specimens of this taxon were first identified by Bonaparte and Sues (2006)
but were misidentified as juvenile ''Clevosaurus brasiliensis'', characteristics such as differences in the configuration of the teeth on the palate, and the unique form of tooth implantation seen in ''C. brasiliensis'', helped differentiate these two co-occurring sphenodontian taxa.
Cladogram following Chambi-Trowell ''et al.'', 2021
References
{{Sphenodontia
Rhynchocephalia
Prehistoric reptile genera
Fossil taxa described in 2021