Mucor septatum C.A. de Souza, T.R. Cordeiro & A.L. Santiago, 2018

Mucor septatum C.A. de Souza, T.R. Cordeiro & A.L. Santiago , sp. nov. ( Fig. 3 View FIGURE 3 )

Index Fungorum number: IF553964

Facesoffungi number: FoF 04593

Holotype: Strain URM 90498, Brazil, August 2015, deposited by C. A. Souza. Slide in the URM herbarium.

Colony low, up to 4 mm in height and 9 cm diam., initially white, becoming dark gray (11B1) with black spots on PDA at 25°C. Reverse slightly zoned and cream (7A7). Sterile mycelium abundant. Sporangiophores gray to brownish, short in the majority, mostly exhibiting one to several septa, rough-walled at some points, some showing a slight constriction near the sporangium, 7 – 20 μm in diam.; erect or bent, simple, sympodially or monopodially branched, mostly intensely branched with occasional swellings. Shorter or longer branches commonly arising from the same or different points on the sporangiophores. Forked branches may occur. Sporangia globose and subglobose, initially yellowish, becoming grayish brown, covered with crystalline spines, 15 – 45 μm in diam. Walls of the largest sporangia evanescent and those of the smaller sporangia persistent, leaving a collar. Columellae gray, mostly applanate, some subglobose, smooth-walled, (5 –) 12.5 – 30 (– 45) × (– 4) 12 – 30 μm. Sporangiospores greenish gray, slightly rough-walled, globose, subglobose, 4.5 – 10 (– 15) μm diam., elliptical, 7.5 – 15.5 × 6 – 10 μm and irregular, 10 – 27.5 × 10 – 15 μm. Zygospores and chlamydospores not observed.

Etymology: The specific epithet ( septatum ) refers to the septa frequently formed in the sporangiophores.

Habitat: Soil.

Distribution: Brejo da Serra do Bitury, Pernambuco, Brazil.

Material examined: BRAZIL, Pernambuco, Brejo da Madre de Deus, (8°12′,41.5′′ S 36°23′,73′′W), in soil samples, 05 August 2015, leg. C.A.F de Souza ( URM 90498 , Holotype) . The ex-type strain was deposited as URM 7364 in the Culture Collection (Micoteca URM) of the Federal University of Pernambuco, Brazil.

Media and temperature tests — On PDA. At 10ºC—very limited growth (3.2 cm in diam. in 168 hours); total lack of reproductive structures; At 15ºC—low colonies (<1mm in height) with slow growth (6 cm in diam. in 168 hours); good sporulation. At 20ºC—colonies up to 3 mm diam. with good growth (9 cm in 120 hours) and good sporulation. At 25ºC—better growth (9 cm in 96 hours) and excellent sporulation. At 30ºC—good growth (8 cm in 96 hours) and excellent sporulation. At 35ºC—lack of growth and sporulation. Mucor septatum exhibited a better growth rate and sporulation on PDA than on MEA at all tested temperatures. At 15ºC, on PDA, the production of reproductive structures was good, and the sporangiophores were simple or slightly sympodially branched, whereas on MEA the production of reproductive structures was very poor and the sporangiophores were simply branched. The columellae were mostly globose (up to 24 μm diam.) at 15ºC on PDA and MEA.