Ostearius

{{Short description| Genus of spiders}}

{{Automatic taxobox

| taxon = Ostearius

| image = Ostearius_melanopygius_male.jpg

| image_caption = O. melanopygius, male

| authority = Hull, 1911

| type_species = O. melanopygius

| type_species_authority = (O. Pickard-Cambridge, 1880)

| subdivision_ranks = Species

| subdivision = 2, see text

| synonyms =

• Haemathyphantes Caporiacco, 1949{{citation| last=Helsdingen| first=P. J. van| year=1977| contribution=Fam. Linyphiidae| title=La faune terrestre de l'île de Sainte-Hélène IV| page=182}}

| synonyms_ref =

}}

Ostearius is a genus of dwarf spiders that was first described by J. E. Hull in 1911.{{cite journal| last=Hull| first=J. E.| year=1911| title=Papers on spiders| journal=Transactions of the Natural History Society of Northumberland| pages=573–590| volume=3| issue=3}}