Oontomyces was the eighth anaerobic fungal genus to be described and the second genus to be defined using both ITS and LSU based DNA barcodes. Like Buwchfawromyces and Piromyces spp., Oontomyces has a monocentric thallus with uniflagellate zoospores and, therefore, can not be reliably characterised based on morphology alone.

Oontomyces has intercalary rhizoidal swellings similar to the intercalary sporangia of Orpinomyces intercalaris but without zoospores. Also, similar to Buwchfawromyces, Oontomyces showed the ITS based highest sequence similarity to Ananeromyces but was morphologically different in terms of having a polycentric thallus. Therefore, the discovery of both the Buwchfawromyces and Oontomyces greatly helped confirm the importance of the simultaneous use of morphological and molecular tools to accurately identify anaerobic fungi.

Oontomyces was formally classified by Dagar et al (2015). The genus name is derived from the Hindi word for ‘camel’ (Oont). This is because Oontomyes was first isolated from the pseudorumen of a camel in India. The type species is called O. anskri, and it is named in honour of Dr. Anil Kumar Srivastava (then Director, ICAR-NDRI, Karnal) by taking the first two, one and three letters of his first, middle and surname (i.e. ANil Kumar SRIvastava = ANKSRI ). To date, no other Oontomyces species or isolates have been described for this genus.

Dagar et al (2015) reported that it was only camel sequences from China that clustered with the Oontomyces type strain, SSD-C1B1. As such, Oontomyces appears to be unusual due to the fact that, so far, its host distribution range seems to be limited to camelids.

Within the family Neocallimastigaceae, Oontomyces is phylogenetically most closely related to Anaeromyces, Liebatanzomyces and Capellomyces (when using LSU as a taxonomic marker).

Images courtesy of Dr Sumit Singh Dagar

Morphology

Images are shown above of the Oontmyces anskri type strain SSD-C1B1.

O. anskri has monocentric thalli typically with a terminal sporangium (Image 1).

The shape of the sporangium can vary from elongate (Images 1-3) to ovoid (Images 4 & 5).

A zoospore filled sporangium showing apical dissolution (Image 2) and constrictions at the base of sporangiophores (Images 4 & 5).

Intercalary rhizoidal swelling (Image 6).

Sequence Information

No sequenced genome or transcriptomes are currently available for Oontomyces.

For Oontomyces anskri strain SSD-CIB1, sequence information is available in the NCBI database (accession number JX017310 for partial 18S, ITS1, 5.8S, ITS2 and partial 28S; accession number JX017314 for partial LSU sequence data).