K. cordensis’s morphology was described on potato dextrose agar (PDA). It optimally grows at 28˚C-32˚C, which distinguishes it from Helicostylum that grows optimally under 20˚C. Furthermore, unlike Helicostylum, K. cordensis lacks spinelike fertile branches. Upadhyay in 1973 describes the species covering a petri dish of PDA in 6 days at 28˚C. It is colorless, translucent, and odorless. Its sporangiophores have few to no septa and are translucent with smooth walls. The sporangiophores are simple and ending in a relatively large, deliquescent-walled terminal sporangium, or they are branched with a terminal sporangium at the end of each branch. Terminal sporangia are globose, translucent, gray olive to olive or brown in age, multispored, and 11-45 µm in diameter. The sporangial wall is incrusted and easily dissolved, but the sporangiospores adhere for a long time. Columellae are subglobose to globose, sometimes ovoid, translucent, smooth, and 9-39 µm in diameter. Sporangiola are globose, bluish olive to olive-gray, 6.5-18 µm in diameter with 4-24 sporangiospores. The sporangiola have a half spherical columella up to 8 µm in diameter with a rough wall. The spores are like the sporangiospores of the terminal sporangia – ovoid, elliptical/irregular, 3.5-7.5 x 2-4.5 µm, translucent, smooth. There are few oidia, which vary in shape and size, and are translucent. Chlamydospores are abundant, elongate, ovoid, globose-irregular, single-celled, and 6.5-15 x 4.5-9 µm or 6-11 µm in diameter5. K. cordensis has also been described as relatively small with persistent-walled sporangiola that arise laterally from sporangiophores or from lateral branchlets with elongate, sterile, spine-like terminations2.
Not much is known about the ecology of this organism except that it is saprobic, culturable on various media types, and that it was isolated from soil as well as mice and rat dung in southern California, USA6. 78% of K. cordensis’s sterols are ergosterol7.
Adopted from Hoffman et al. 2013, the above link shows a revised phylogeny displaying familial relationships of Mucorales based on coding sequences for actin, translation elongation factor 1-alpha, and 18S and 28S rDNA data.
Kirkomyces cordensis (synonyms Kirkea cordense, Kirkomyces cordense and previously known as Helicostylum cordense) is a fungus authorized by B.S. & B.R. Mehrotra in 19631. K. cordensis was originally isolated from soil in India and described as Helicostylum cordense in the family Thamnidiaceae, order Mucorales, subphylum Mucoromycotina, phylum Mucoromycota, and kingdom Fungi, but was reclassified in its own genus in 1995 due to morphological analysis2.Further molecular analysis of 18S rDNA and 28S rDNA deemed Thamnidiaceae paraphyletic3.K. cordensis was placed into the family Mucoraceae upon Bayesian analysis of the sequences coding for actin, translation elongation factor 1-alpha, 18S rDNA and 28S rDNA. Kirkomyces cordensis’s closest relatives are Mucor amphibiorum and Mucor indicus 4.