Protocaris

{{Short description|Genus of small freshwater animals}}

{{Italic title}}

{{Taxobox

| image = Protocaris.png

| image_caption = P. marshi

| regnum = Animalia

| phylum = Arthropoda

| classis = incertae sedis

| ordo = {{extinct}}Hymenocarina

| familia = {{extinct}}Protocarididae

| genus = Protocaris

| genus_authority = Walcott, 1884 {{cite book |author=Charles Doolittle Walcott |year=1884 |title=On the Cambrian faunas of North America. Preliminary studies |volume=10 |series=Bulletin of the United States Geological Survey |publisher=USGS |chapter=On a new genus and species of Phyllopoda from the Middle Cambrian |pages=50–51 |chapter-url=https://books.google.com/books?id=fCuOzw954VoC&pg=PA50|author-link=Charles Doolittle Walcott }}

| species = Protocaris marshi

| fossil_range = {{fossilrange|Cambrian Series 2}}

| image2 = USNM PAL 15400 Protocaris marshi.jpg

| image2_caption = Holotype specimen

}}

Protocaris marshi is an extinct species of bivalved arthropod known from a single specimen collected from the Cambrian Series 2 aged Parker Formation from the Parker Quarry of northwestern Vermont, United States{{cite book |author=Charles Doolittle Walcott |year=1886 |title=Second contribution to the studies on the Cambrian faunas of North America |volume=30 |series=Bulletin of the United States Geological Survey |publisher=USGS |url=https://books.google.com/books?id=wikrAAAAYAAJ |pages=11–71 |chapter=Introductory observations|author-link=Charles Doolittle Walcott }}{{Cite journal |last1=Pari |first1=Giovanni |last2=Briggs |first2=Derek E.G. |last3=Gaines |first3=Robert R. |date=2022-02-16 |title=The soft-bodied biota of the Cambrian Series 2 Parker Quarry Lagerstätte of northwestern Vermont, USA |journal=Journal of Paleontology |volume=96 |issue=4 |pages=770–790 |doi=10.1017/jpa.2021.125 |issn=0022-3360|doi-access=free |bibcode=2022JPal...96..770P }} The specimen is preserved in top-down view and has a bivalved carapace, a segmented trunk and a forked tail. Its precise taxonomic position is uncertain, due to the limited nature of known remains, but it is suggested to be a member of Hymenocarina belonging to the family Protocarididae, which also includes Tokummia and Branchiocaris.{{Cite journal |last1=Aria |first1=Cédric |last2=Caron |first2=Jean-Bernard |date=2017-04-26 |title=Burgess Shale fossils illustrate the origin of the mandibulate body plan |url=http://dx.doi.org/10.1038/nature22080 |journal=Nature |volume=545 |issue=7652 |pages=89–92 |doi=10.1038/nature22080 |bibcode=2017Natur.545...89A |issn=0028-0836|url-access=subscription }}