First evidence of <i>Trichomerium</i> -like (Trichomeriaceae) fossil fungi from India and its implications

Trichomeriaceae, the most common sooty mold family under Chaetothyriales, are most common in tropical to subtropical regions worldwide. However, no trichomeriaceous fossil fungi have been reported until now. Here, we report for the first time trichomeriaceous fossil fungi on cuticle fragments of a compressed angiosperm (cf. Fagaceae) leaf recovered from the middle Siwalik (late Miocene; ca. 12-8 Ma) flora of Himachal Himalaya. They are characterized by superficial, septate, cylindrical hyphae; circular, setiferous ascostromata; a 3-septate ascospore; and a 3-armed stauroconidium. The above significant morphological attributes reveal a close resemblance of the Siwalik fungi with modern <i>Trichomerium</i> (Eurotiomycetes: Chaeothyriales: Trichomeriaceae). Here, we describe two new fossil species, namely, <i>Trichomerium palaeoindicum</i> Kundu & Khan, sp. nov. (sexual morph), and <i>T. palaeostauroconidium</i> Kundu & Khan, sp. nov. (asexual morph). Additionally, we discuss their paleoecological significance in terms of the present-day ecological conditions of modern analogues. These new findings play a great role in the evolutionary context and diversification of the Trichomeriaceae in time and space.