Lachnostoma

{{Short description|Extinct genus of trilobites}}

{{Automatic taxobox

| fossil_range = Early Arenig

| taxon = Lachnostoma

| authority = Ross, 1951

| subdivision_ranks =Species

| subdivision =

• L. latucelsum

}}

Lachnostoma is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the early part of the Arenig stage of the Ordovician Period,{{cite journal |last=Sepkoski |first=Jack |title=A compendium of fossil marine animal genera (Trilobita entry) |journal=Bulletins of American Paleontology |volume=364 |page=560 |year=2002 |url=http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=307&rank=class |accessdate=2008-01-12 |url-status=dead |archiveurl=https://web.archive.org/web/20060905162524/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=307&rank=class |archivedate=2006-09-05 }} a faunal stage which lasted from approximately 478 to 471 million years ago.