Alacaris

{{Short description|Extinct genus of arthropods}}

{{Automatic taxobox

| fossil_range = {{fossil range|Cambrian Stage 3}}

| type_species = Alacaris mirabilis

| type_species_authority = Yang et al, 2018

| image = Alacaris multinoda fossil (cropped).jpg

| image_caption = YKLP 12269 largely complete specimen in lateral view

| image2 = 20211117 Alacaris mirabilis.png

| image2_caption = Alacaris Reconstruction

| taxon = Alacaris

| authority = Yang et al, 2018

}}

File:Alacaris restoration.jpg

File:Alacaris multinoda fossil.jpg

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.{{Cite journal|last1=Yang|first1=Jie|last2=Ortega-Hernández|first2=Javier|last3=Legg|first3=David A.|last4=Lan|first4=Tian|last5=Hou|first5=Jin-bo|last6=Zhang|first6=Xi-guang|date=2018-02-01|title=Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods|journal=Nature Communications|volume=9|issue=1|page=470|doi=10.1038/s41467-017-02754-z|pmid=29391458|pmc=5794847|bibcode=2018NatCo...9..470Y|issn=2041-1723|doi-access=free}}