Abstract During a survey of mucoralean fungi in soil from an upland forest area located in Pernambuco, Brazil, a strain of Backusella (URM 8637) was isolated. Based on morphological, physiological, and molecular data [internal transcribed spacer (ITS) and large subunit (LSU) ribosomal DNA regions], it was recognized that this Backusella differed from all other species in the genus. Morphologically, the new species is characterized as forming varied-shaped columellae, including elongated, basally constricted, unisporate (rare) and multisporate sporangiola, and ellipsoidal sporangiospores. The maximum temperature growth of URM 8637 on malt extract agar and potato dextrose agar was 36 °C. In the phylogram, it was closely related to B. constricta. Based on the evidence from the analyzed datasets, a new species of Backusella is proposed. An updated identification key for Backusella from the Americas is provided. Pernambuco Brazil isolated morphological physiological internal ITS (ITS LSU (LSU regions, regions , regions] genus Morphologically variedshaped varied shaped columellae elongated constricted rare (rare sporangiola sporangiospores 863 3 C °C phylogram B constricta datasets proposed provided 86 8

ABSTRACT During a survey of Mucorales in soil from an upland forest area in Pernambuco, Brazil, two specimens were isolated and characterized based on their morphological, physiological, and molecular data (ITS and LSU rDNA). Phylogenetic analyses of the isolates revealed that the strains URM 8209 and URM 8210 are closely related to species of Absidia. URM 8209 forms conical, subglobose, and strawberry-shaped columellae and the sporangiospores are cylindrical and ellipsoid. URM 8210 produces hemispheric, subglobose, and strawberry-shaped columellae and the sporangiospores are globose, subglobose, ellipsoid, and short cylindrical. Based on evidence obtained through analysis of datasets (LSU and ITS rDNA regions), A. saloaensis sp. nov. (URM 8209) and A. multispora sp. nov. (URM 8210) are proposed here as novel species of Absidia. A table with morphological characteristics of Neotropical Absidia spp. is provided.