Alacaris

Alacaris is an extinct genus of fuxianhuiid arthropod known from the Cambrian period. It is only known from the type species Alacaris mirabilis (mistakenly named Alacaris multinoda in a figure in the describing paper) from the Cambrian Stage 3 aged Xiaoshiba Lagerstätte in Yunnan Province, China. It is morphologically similar to Chengjiangocaris, with which it forms a clade within Fuxianhuiida. Individuals reach a maximum of 12 centimetres in length, with a trunk consisting of 13 tergites. The basal region of the post-deutocerebral limbs were used in feeding, with the rhythmic movement of the legs guiding food towards the mouth along the food groove between the limbs, with gnathobases present near the mouth to macerate food.[1]

Alacaris Temporal range: Cambrian Stage 3 PreꞒ Ꞓ O S D C P T J K Pg N
YKLP 12269 largely complete specimen in lateral view
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Order:	†Fuxianhuiida
Family:	†Chengjiangocarididae
Genus:	†Alacaris Yang et al, 2018
Type species
Alacaris mirabilis Yang et al, 2018

Reconstruction of Alacaris, with Chengjiangocaris lower right

Various specimens of Alacaris

Phylogeny

	Fuxianhuiida     Shankouia     Liangwangshania       Chengjiangocarididae   Alacaris     Chengjiangocaris     Fuxianhuiidae   Fuxianhuia     Guangweicaris

References

1. Yang, Jie; Ortega-Hernández, Javier; Legg, David A.; Lan, Tian; Hou, Jin-bo; Zhang, Xi-guang (2018-02-01). "Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods". Nature Communications. 9 (1). doi:10.1038/s41467-017-02754-z. ISSN 2041-1723.