''Haikoucaris'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
megacheira
Megacheira ("great hands") is an extinct class of predatory arthropods that possessed a pair of great appendages, hence the class name as well as the common name "great appendage arthropods". Their taxonomic position is controversial, with stud ...
n
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
that contains the single species ''Haikoucaris ercaiensis''. It was discovered in the
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
Chengjiang biota
The Maotianshan Shales are a series of Early Cambrian deposits in the Chiungchussu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales ...
of
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
.
Morphology
''Haikoucaris'' measured about 38 mm in body length.
The elongated body compose of a semicircular head shield, 13 trunk
tergite
A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...
s and presumely a short, spine-like
telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...
.
The head possess a pair of unstalked eyes, a pair well-developed
great appendage
Great appendages are claw-like appendages which attach to the heads of the "great appendage arthropods", a name usually refers to Megacheira, a class of extinct arthropod characterized by a pair of "short-great appendages" bearing in front of the ...
s, as well as 3 more appendage pairs of unknown detail.
Each of the great appendage consists of a 2-segmented peduncle and a 3-segmented claw.
Each of the trunk segment possess a pair of biramus appendages that each comprising a leaf-shaped exopod and a possibly 7-segmented endopod.
Paleoecology
''Haikoucaris'' may have been a
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
, with its great appendages and exopod suggested to be used for hunting and swimming respectively.
Taxonomy
Within megacheirans, ''Haikoucaris'' is generally accepted to be a member of the clade Cheiromorpha alongside ''
Yohoia
''Yohoia'' is an extinct genus of megacheiran arthropod from the Cambrian period that has been found as fossils in the Burgess Shale formation of British Columbia, Canada. It has been placed among the arachnomorpha, a group of arthropods that in ...
'' and
Leanchoiliidae
Megacheira ("great hands") is an extinct class of predatory arthropods that possessed a pair of great appendages, hence the class name as well as the common name "great appendage arthropods". Their taxonomic position is controversial, with stud ...
.
See also
*
Cambrian explosion
The Cambrian explosion, Cambrian radiation, Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately in the Cambrian Period when practically all major animal phyla started appearing in the fossil recor ...
*
Chengjiang biota
The Maotianshan Shales are a series of Early Cambrian deposits in the Chiungchussu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales ...
**
List of Chengjiang Biota species by phylum
This is a list of fossils found at Maotianshan Shales, whose most famous assemblage of organisms are referred to as the Chengjiang biota.
Phylum Arthropod, Arthropoda
80 species, not counting Dinocarida, Nektaspida and Trilobita
* ''Ac ...
References
{{Taxonbar, from=Q1325020
Megacheira
Cambrian arthropods
Maotianshan shales fossils
Prehistoric arthropod genera