Complex sentence: It is assumed to be (or to have been) endemic to the densely forested Mbhashe River area of the Eastern Cape in South Africa, where searches subsequent to its discovery failed to yield any trace of it.
Split into simpler sentences: It is assumed to be (or to have been) endemic to the densely forested Mbhashe River area of the Eastern Cape, South Africa. Searches subsequent to its discovery however failed to yield any trace of it.