Passer predomesticus is a fossil passerine bird in the sparrow family Passeridae. First described in 1962, it is known from two premaxillary (upper jaw) bones found in a Middle Pleistocene layer of the Oumm-Qatafa cave in Palestine. The premaxillaries resemble those of the house and Spanish sparrows, but differ in having a deep groove instead of a crest on the lower side. Israeli palaeontologist Eitan Tchernov, who described the species, and others have considered it to be close to the ancestor of the house and Spanish sparrows, but molecular data point to an earlier origin of modern sparrow species. Occurring in a climate Tchernov described as similar to but rainier than that in Palestine today, it was considered by Tchernov as a "wild" ancestor of the modern sparrows which have a commensal association with humans, although its presence in Oumm-Qatafa cave may indicate that it was associated with humans.
Premaxillae, the only bones from which Passer predomesticus is known, are generally relatively easy to identify to species in birds. Tchernov found that the two premaxillae of P. predomesticus most closely resembled the house and Spanish sparrows, but were distinct from either. In P. predomesticus, there is a central, longitudinal groove with raised margins running along the lower (ventral) side of the premaxilla. In contrast, the house and Spanish sparrows have a narrow crest in this position, which is more prominent in the house sparrow. In the great sparrow, Cape sparrow (Passer melanurus ), and southern grey-headed sparrow (Passer diffusus ), this crest is more poorly developed, and they may even have a shallow groove at the front of the premaxilla, not nearly as well-developed as the groove in P. predomesticus. In P. predomesticus, the premaxilla has a maximum width of 8.0 millimetres (0.31 in) and the length from the tip of the premaxilla to the back of the nasal bones is 12.0 millimetres (0.47 in).
According to Tchernov's 1962 paper, Passer predomesticus was found in the middle Acheulean (middle Pleistocene, probably more than 400,000 years old) layer E 1 of the Oumm-Qatafa cave in Wadi Khareitoun near Bethlehem. In 1984, however, Tchernov wrote that P. predomesticus was about 140,000 years old, from the Yabrudian. Layer E 1 contained remains of about 40 bird species, including a premaxilla Tchernov described as a precursor of the Dead Sea sparrow (Passer moabiticus ) and a tarsometatarsus and humerus tentatively allied with the house sparrow. An undetermined Acheulean layer of the same cave also contained fossils Tchernov described as precursors of both the house and Spanish sparrows.
Although interpretations of the palaeoclimate at Oumm-Qatafa have differed, Tchernov suggested that the deposits are from a Mediterranean climate, although one rainier than that today. Tchernov considered P. predomesticus a "wild" sparrow, but Anderson considered that the occurrence of P. predomesticus and the other Passer fossils in Oumm-Qatafa indicates that these species lived in association with early Palaeolithic humans.
