## 4 Discussion
On the other hand, the lack of distinct micro-morphological traits (neither sexual nor asexual morph with differentiated conidiogenesis detected) and the huge variability observed among the colonies (in terms of growth rate, texture, surface and reverse color) lead us to introduce the \(C\). _mediterranea_ species complex (CMSC), since we could not discern the species boundaries with certainty (Figures 5 and 6). Indeed, the term \"species complex\" comes to help taxonomists when: (i) a group of organisms may represent more than one species; (ii) morphological features are overlapping due to extreme variability; (iii) the species may be somehow related although no certain assumption can be assessed. Furthermore, no clear correlation between colony features, growth rates, source of isolation, and/or phylogenetic position was noticed. In general, researchers introduce a species complex when facing a problematic topic. This is the case for example of _Fusarium oxysporum_ species complex (FOSC) [50; 51], _Fusarium solani_ species complex (FSSC) [52], _Walemia sebi_ species complex (WSSC) [53], _Colletotrichum acutatum_ species complex (CASC) [54] and many others. Most of these cases were resolved with a revision of the species complex, where individual species were identified based on a multi-loci phylogeny. However, in our study, this approach did not lead to a sharp resolution of the complex. The genome sequencing of all the strains investigated would be an option to sort out this intriguing issue. This approach would possibly reveal those genetic regions that may allow an easy distinction of the species within the complex [55]. On the other hand, the same goal could be achieved by the analysis of secondary metabolites [53]. An investigation of this sort is important also from another point of view: it is now recognized that marine fungi are a reservoir of novel active metabolites that can be harnessed for pharmaceutical, nutraceutical, cosmetic, and environmental purposes. [PERSON] and [PERSON] [10] demonstrated that a number of strains of \(C\). _maritima_, \(C\). _lacera_, and \(C\). _intermediate_ were capable of using hexadecane as the sole carbon source, and assumed that the genus _Corollospora_ could find utility in petroleum degradation. Supporting this idea is the isolation of 4 strains of \(C\). _mediterranea_ (MUT 1938, MUT 1950, MUT 1954, and MUT 1961) from a site chronically contaminated by an oil spill in the Mediterranean Sea [28]. The aforementioned findings indicate the great versatility and adaptability of these fungi to hydrocarbons-contaminated environments, with the consequent possibility of being used as bioremediators. In addition, knowing that the species of _Corollospora_ belong to a family of lignicolous fungi and that are rich in cellulase and lignin-degrading enzymes [7], their retrieval from leaves of the seagrass \(P\). _oceanica_ (MUT 5040, MUT 5048, MUT 5049, and MUT 5082) and from driftwood (MUT 1587) does not come as a surprise. It is, therefore, reasonable to assume a role of \(C\). _mediterranea_ in degrading and recycling organic matter, making them available for other organisms. Figure 5: _Corollospora mediterranea_ sp. nov. 28-days-old colonies at 21 \({}^{\circ}\)C on MEASW: (**A**) MUT 1587, (**B**) MUT 1938, (**C**) MUT 5049 (strains belonging to the Clade 1, Subclade 1a); (**D**) MUT 5048, (**E**) MUT 5082, (**F**) MUT 5040 (strains belonging to the Clade 1, Subclade 1b); (**G**) MUT 1954, (**H**) MUT 1961 (strains belonging to the Clade 2).