''Houcaris'' is a possibly paraphyletic

radiodont Radiodonta is an extinct 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 used for a variety ...

genus, tentatively assigned to either Amplectobeluidae,

Anomalocarididae Anomalocarididae (occasionally mis-spelt Anomalocaridae) is an extinct family of Cambrian radiodonts, a group of stem-group arthropods. Around 1990s and early 2010s, Anomalocarididae included all radiodont species, hence the previous equivalen ...

or Tamisiocarididae, known from

Cambrian Series 2 Cambrian Series 2 is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Miaolingian. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower boundary ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''Houcaris saron'' which was originally described as a species of the related genus ''

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 ...

''. Other possible species include ''H. magnabasis'' and ''H. consimilis''. The genus ''Houcaris'' was established for the two species in 2021 and honors Hou Xianguang, who had discovered and named the

''Anomalocaris saron'' in 1995 along with his colleagues Jan Bergström and Per E. Ahlberg.

Species

''Houcaris saron''

20191221 Radiodonta frontal appendage Houcaris saron.png, Frontal appendage of ''H. saron'' 20191029 Outdated Anomalocaris saron.png, Outdated, chimeric reconstruction based on frontal appendage of ''H. saron'' and body of ''Innovatiocaris'' that was previously considered as whole body fossil of ''H. saron'' ''H. saron'', known from Maotianshan Shale in

Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

, is first described in 1995 as ''Anomalocaris saron''. This species is only known from frontal appendages. There is a specimen (ELRC 20001) that is previously considered as whole body fossil of this species, but later study shows that this specimen is not belonging to this species, and later given own genus '' Innovatiocaris''. Length of frontal appendage is up to at least 12 cm. Sometimes considered to belong to family

or Amplectobeluidae.

''Houcaris''? ''magnabasis''

20191221 Radiodonta frontal appendage Anomalocaris magnabasis.png, Frontal appendage of ''H. magnabasis'' ''H.''? ''magnabasis'', known from Pioche Shale and Pyramid shale in

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

, is originally described as ''Anomalocaris'' cf. ''saron'' in 2003, and later named as ''Anomalocaris magnabasis'' in 2019. This species is only known from frontal appendages and some partial fossils of oral cone (mouthpart) and flaps. Largest estimated length of frontal appendage is 17.5 cm. Sometimes considered to belong to family

or Amplectobeluidae. However, results from the phylogenetic analysis by McCall in 2023 suggest that ''H.''? ''magnabasis'' does not form a monophyletic clade with other species of ''Houcaris'', and that it is a sister taxon of the Amplectobeluidae. Thus, he tentatively referred to the species as ''Anomalocaris magnabasis'', even though the results show that it also does not form a clade with known species of ''Anomalocaris''.

''Houcaris''? ''consimilis''

''H.''? ''consimilis'' is known from the

Maotianshan Shales The Maotianshan Shales () are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation or Heilinpu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized orga ...

of South China and possibly the Latham Shale of California. While this species was originally described within '' Ramskoeldia'' and a sister taxon of its type species (''R. platyacantha''), subsequent studies have rejected their monophyly. In 2022, this species was recovered as a basal member of the Tamisiocarididae close to ''H. saron'' by the describers of '' Innovatiocaris'', and not monophyletic with ''R. platyacantha''. In 2023, on the basis of phylogenetic analysis and morphological comparison, McCall suggested that it does not form a monophyletic clade with ''R. platyacantha'', but instead with ''H. saron'', so he included this species within the genus as ''Houcaris consimilis''. His results also consistently recover both species as a member of the Amplectobeluidae. Based on their phylogenetic analysis from the 2024 study describing '' Shucaris'' and the first-known oral cone of ''H''? ''consimilis'', Wu and colleagues recovered ''H''? ''consimilis'' as an amplectobeluid, but not as a sister taxon of ''R. platyacantha'', and rejected the tamisiocaridid affinity.

References

Cambrian arthropods of North America Cambrian arthropods of Asia Fossil taxa described in 2021 Cambrian genus extinctions Radiodonta {{Cambrian-animal-stub