Question

What feature of chytrids supports the hypothesis that they include members of basal fungal lineages?

Short answer

The presence of flagellated spores, also called zoospores in chytrids, is evidence to support the hypothesis that they include members of basal fungal lineages.

Step-by-step solution

Fungal diversity

Molecular analyses and metagenomic studies can study fungal diversity and evolutionary relationships. Some extant fungal groups include chytrids, zygomycetes, glomeromycetes, ascomycetes, and basidiomycetes.

Fungi have colossal diversity, with the actual variety including nearly 1.5 million species, of which only 100000 are known species. A newly discovered phylum in the kingdom fungi is Cryptomycota.

Chytrids

Chytrids are fungi that belong to the phylum Chytridiomycota. They are primarily found in lakes and soil. Some clades of these fungi live in hydrothermal vents and marine environments. Chytrids are found as decomposers and parasites.

Chytrids also establish mutualistic relationships. For instance, anaerobic chytrids present in the gut of cattle help in the breakdown of food such as plant matter and thus aid in the cattle’s growth.

Feature of chytrids relating to basal fungal lineage

Chytrids are unique species among fungi. Chytrids possess flagellated spores, known as zoospores. As a result, chytrids are also called zoosporic fungi. The presence of chytrids in an aquatic environment and the absence of a complex root structure arise the necessity of zoospores. These zoospores are motile.

Most of the fungi have motile, flagellated spores. Some early diverging fungi lost their flagella and diverged from flagellated ancestors. However, the presence of zoospores in chytrids suggests a deep divergence and includes basal fungal lineages. Chytrids and zygomycetes descended from the same ancestral group.