Anomalocarididae (occasionally mis-spelt Anomalocaridae) 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 ...
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of
Cambrian
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...
radiodonts, a group of
stem-group arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...
s.
Around 1990s and early 2010s, Anomalocarididae included all radiodont species, hence the previous equivalent of the common name "anomalocaridid" to the whole
Radiodonta
Radiodonta is an extinct Order (biology), order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and were u ...
. This is no longer the case after the revision done by Vinther et al. 2014,
as Anomalocarididae restricted to only ''
Anomalocaris
''Anomalocaris'' (from Ancient Greek , meaning "unlike", and , meaning "shrimp", with the intended meaning "unlike other shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group marine arthropods.
It is best known fro ...
'' and, if any, a few of closely related genera since then. Wu et al. 2021 accepted only ''Anomalocaris'' (excluding ''
"A." saron'', ''
"A." kunmingensis'' and ''
"A." briggsi'') and ''
Lenisicaris'' as the member of Anomalocarididae,
while ''
Paranomalocaris'' is questionably included by some studies as well.
Since then, other species labeled under the ''Anomalocaris'' genus, like ''
''A.'' saron'' have been reassigned to their own genus (like in the case of ''
''A.'' saron'' being redescribed as ''
Innovatiocaris'').
Anomalocarididae distinguished from the similar family
Amplectobeluidae (e.g. ''
Amplectobelua'', ''
Lyrarapax'') by the presence of triradial oral cone and non-hypertrophied first distal endite.
Compared to
Hurdiidae and
Tamisiocarididae, this two radiodont families shared a lot of characters (i.e. alternated endite length;
streamlined body;
small head with ovoid sclerites;
well-developed swimming flaps;
caudal furcae;
raptorial predatory lifestyle
) and forming a clade in multiple
phylogenetic analysis.
See also
*''
Lenisicaris''
References
{{Taxonbar, from=Q134939
Radiodonta
Cambrian Series 2 first appearances
Guzhangian extinctions
Prehistoric arthropod families