Lulworthiales was introduced based on morphology and LSU and SSU phylogeny to accommodate the genera Lulworthia and Lindra, which were initially accommodated in Halosphaeriales (Kohlmeyer et al. 2000). All taxa referred to this order are marine aquatic fungi. The order is accommodated in Lulworthiomycetidae, where it forms a strongly-supported clade with Koralionastetales (Maharachchikumbura et al. 2016b) with a divergent age of 289 MYA (Hongsanan et al. 2017). Lulworthia is polyphyletic, as observed from the combined LSU, SSU and
ITS phylogeny (Fig.). This is in accordance with other studies which also reported the polyphyly of Lulworthia (Jones et al. 2008, 2009, 2019, Abdel-Wahab et al. 2010, Azevedo et al. 2017). Spathulosporaceae, typified by Spathulospora is also reported to group in Lulworthiales (Jones et al. 2019). Spathulosporaceae was initially placed in Spathulosporales based on morphology (Kohlmeyer 1973), but molecular data of some Spathulosporaceae species have shown that the taxa have a higher affinity to Lulworthiales, even though the type species of Spathulosporaceae was not included, since it lacks sequence data (Inderbitzin et al. 2004, Campbell et al. 2005, Jones et al. 2009). Currently there is one family (the placement of Spathulosporaceae is not confirmed in Lulworthiales) and 15 genera in this order with both asexual and sexual morphs (Hyde et al. 2020). Further studies are required to resolve the higher order rank of the marine algicolous parasites Spathulospora.