Few-spored sporangiola (Fig 1) and multispored sporangia (Fig 2) of Helicostylum pulchrum. Images by Kerry O'Donnell.

Helicostylum pulchrum is a psychrotolerant member of the order Mucorales (phylum Mucoromycota; Spatafora et al. 2016), which is occasionally isolated from refrigerated meat.  Historically it was classified within the Thamnidiaceae based on morphological criteria; however, a molecular phylogenetic analysis revealed this family circumscription is polyphyletic (O’Donnell et al. 2001).  Phylogenetic analysis of partial nuclear ribosomal large subunit sequences place Helicostylum in the Mucor flavus group (Walther et al. 2013).  Asexual reproduction in H. pulchrum is by few-spored sporangiola (Fig. 1) and by multispored sporangia that are borne terminally on simple or branched sporangiophores (Fig. 2).  Comparative phylogenomic analyses that include whole-genome sequence data of H. pulchrum should provide insight into the evolution of early diverging fungi, thereby advancing the primary objective of the 1000 Fungal Genome Project.

References:

O’Donnell K, Lutzoni F, Ward TJ, Benny GL. 2001. Evolutionary relationships among mucoralean fungi (Zygomycota): Evidence for family polyphyly on a large scale. Mycologia 93:286─296.

Spatafora JW, Chang Y, Benny GL, Lazarus K, Smith ME, Berbee ML, Bonito G, Corradi N, Grigoriev I, Gryganskyi A, James TY, O’Donnell K, Roberson RW, Taylor TN, Uehling J, Vilgalys R, White MM, Stajich JE. 2016. A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data. Mycologia 108:1028─1046.

Walther G, Pawłowska J, Alastruey-Izquierdo A, Wrzosek M, Rodriguez-Tudela JL, Dolatabadi S, Chakrabarti A, de Hoog GS. 2013. DNA barcoding in Mucorales: an inventory of biodiversity. Persoonia 30:11–47.