I have never heard of Anubias dying solely from being grown submersed. Excerpts from my online profile:
Origin and Habitat: Tropical central and west Africa. Found in rivers, streams and in marshes. Species in the genus are aquatic or semi-aquatic.
Ideal position in aquarium
May be attached to rock or wood and used throughout the aquarium but not in direct bright light [see comments under Lighting requirements].
Lighting requirements
Low to moderate. It often develops yellowing spots on the leaves in bright light (unless nutrients including CO2 are high to balance), and in most natural aquaria should preferably be grown in shade or under diffused light such as under floating plants. Algae will not be so likely to grow on the leaves in subdued or low light.
Water parameters
Soft to medium hard (< 15 dGH), acidic to slightly basic (pH 6 to 8) water, temperature 22-27C/71-81F. Almost all variants of this species will grow well within the stated parameters.
Description
Anubias barteri is the most commonly available species of Anubias and there are several varieties having different leaf forms and varying in overall size. A. barteri var. nana is the smallest and the species most often seen in the hobby. The requirements given here (water parameters, light, nutrients) are basically the same for all of these.
All species in the genus have dark green, thick and usually broad leaves. This plant is a good choice for "difficult" situations. It prefers low light and does very well even when shaded by other plants. Most fish that are herbivorous will not eat Anubias. As it is attached to rock and wood, it will not be uprooted by fish that dig in the substrate. It can be used in a plaudarium and grown emersed provided the rootstock is under water.
Anubias should not be planted in the substrate with the stolon (rhizome) buried or the plant will deteriorate. Similar to Java Fern, the rhizome should be affixed to wood or rock with black cotton thread and the roots will attach the plant in a few weeks.
Algae frequently attaches itself to the leaves of this plant, especially brush algae; keeping it in low or subdued light will help to prevent this.
Anubias may be reproduced by dividing the rhizome; ensure there are several leaves and some roots emerging from each piece of rhizome. Sideshoots from the rhizome will develop and these may also be removed as new plants. Most species will produce submersed flowers in theaquarium; one of the photos above depicts A. barteri var nana in flower. Growth of all species is slow, with one leaf every 3-4 weeks at best. Under very poor conditions (neglect), the plant has been known to grow in miniature.
The Araceae is a family of flowering plants in which the flower is borne on an inflorescence known as a spadix which is usually partially enveloped by a leaf-like bract called a spathe [see photo below]. Also known as the Arum family, there are more than 3700 species in 107 genera. The genus Anubias was named by the Austrian botanist Heinrich Wilhelm Schott (1794-1865). Schott described the species A. barteri in 1860. A. barteri var. nana was originally described by Adolf Engler in 1899 as a distinct species, Anubias nana; it was reduced to varietal status by Crusio in 1979.
References:
Crusio, W. (1979), "A revision of Anubias Schott (Araceae)," Primitiae Africanae XII, Mededelingen Landbouwhogeschool Wageningen 79 (14), pp. 1-48.