what is the former mentioned one?
An extinct species of passerine bird from the early Oligocene of Germany
Wieslochia
Wieslochia weissi is an extinct species of passerine bird from the early Oligocene (27.8 - 33.9 Ma) of Germany. 
what is african river martin? A passerine bird what is the origin and evolution of this former mentioned species? It is one of two members of the river martin subfamily of the swallow family, Hirundinidae. what are its earliest species? UNANSWERABLE what is its anatomy? A large swallow, mainly black with a blue-green gloss to the head and a greener tint to the back and wings. The under-wings are brownish, the underparts are purple-black, and the flight feathers are black. what are its taxonomy? UNANSWERABLE name few earliest of this family passerine "Wieslochia", "Jamna", and "Resoviaornis"
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Wieslochia [SEP] Introduction
Wieslochia weissi is an extinct species of passerine bird from the early Oligocene (27.8 - 33.9 Ma) of Germany. Remains of this species have been found in a clay pit in Frauenweiler near Wiesloch, Germany. The holotype is a dissociated skeleton on two slabs. Another specimen consisting on a mandible and a cranium has been found in the same horyzon. The taxonomic affinities of "Wieslochia" are not well understood as it shares some similarities with suboscines but it seems more primitive in other features.