Strigogyps sapea ("Thinking Owl Vulture") is a species of prehistoricbird. It initially was described as the single species of the genus Aenigmavis ("enigmatic bird"). This bird is known from fossil remains found in the Middle Eocene deposits of the Messelshale. It probably was around the size of a large chicken or a guan, weighing not quite 1 kilogram. Apparently, as indicated by the ratio of lengths of wing to leg bones, S. sapea was flightless. Its legs were not adapted to running, so it seems to have had a walking lifestyle similar to trumpeters, but probably was more carnivorous, feeding on small reptiles, possibly mammals or fish caught in shallow water, or carrion.
Strigogyps sapea was previously - as Aenigmavis - believed to be a primitive European phorusrhacid (terror bird), but more recent study has found this to be poorly supported (Alvarenga & Höfling 2003, Mayr 2005). The genus Strigogyps was initially placed in the owl orderStrigiformes and considered to be a sophiornithid. The present species has been suggested to be closer to Salmila robusta, a gruiform from the Messel Pit (Mayr 2005). Consequently, Peters (2007) supports separation in the Ameghinornithidae. He also considers Strigogyps to contain the species S. dubius only, which by Mayr (2005) is united with Ameghinornis minor.
References
Alvarenga, Herculano M. F. & Höfling, Elizabeth (2003): Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Papéis Avulsos de Zoologia43(4): 55-91 PDF fulltext
Mayr, Gerald (2005): "Old World phorusrhacids" (Aves, Phorusrhacidae): a new look at Strigogyps ("Aenigmavis") sapea (Peters 1987). PaleoBios (Berkeley)25(1): 11-16 HTML abstract
Peters, Dieter Stefan (1987): Ein "Phorusrhacidae" aus dem Mittel-Eozän von Messel (Aves: Gruiformes: Cariamae). Documents des Laboratoires de Géologie de Lyon99: 71-87. [Article in German]
Peters, Dieter Stefan (2007): The fossil family Ameghinornithidae (Mourer-Chauviré 1981): a short synopsis. Journal of Ornithology148(1): 25-28. doi:10.1007/s10336-006-0095-zPDF fulltext