▁Tax onomy ▁The ▁genus ▁was ▁circ ums cribed ▁in ▁ 2 0 1 2 ▁by ▁my colog ists ▁Otto ▁Mi ett inen ▁and ▁Mario ▁Raj chen berg . ▁The ▁three ▁species ▁are ▁members ▁of ▁the ▁Cin ere omy ces ▁cla de , ▁a ▁grouping ▁of ▁ph y log en et ically ▁related ▁fung i ▁distinct ▁from ▁the ▁core ▁pol yp or oid ▁cla de . ▁ ▁O .   riv ul osa ▁was ▁introduced ▁to ▁science ▁by ▁Mil es ▁Joseph ▁Ber keley ▁and ▁Mos es ▁Ash ley ▁Curt is ▁in ▁ 1 8 6 9 ▁as ▁Pol yp orus ▁riv ulos us . ▁The ▁type ▁species , ▁O .   val div iana , ▁was ▁originally ▁described ▁as ▁a ▁variety ▁of ▁Cer ip ori opsis ▁riv ul osa ▁by ▁Raj chen berg ▁in ▁ 1 9 9 5 . ▁The ▁genus ▁was ▁formally ▁transferred ▁to ▁the ▁new ▁family ▁Gel at op oria ceae ▁in ▁ 2 0 1 7 . ▁ ▁The ▁generic ▁name ▁O bb a ▁all udes ▁to ▁the ▁similarity ▁of ▁the ▁bott le - sh aped ▁c yst idi oles ▁characteristic ▁of ▁the ▁genus ▁to ▁the ▁household ▁containers ▁for ▁liqu ids ▁used ▁in ▁Rome . ▁ ▁Description ▁O bb a ▁species ▁have ▁cr ust - like ▁fruit ▁bodies ▁that ▁are ▁white ▁( when ▁young ) ▁or ▁cre am ▁to ▁och re ▁( when ▁dry ). ▁They ▁range ▁in ▁length ▁from ▁a ▁few ▁mill imet res ▁up ▁to ▁ ▁long , ▁and ▁are ▁about ▁ 3   mm ▁thick . ▁O