Two new species of flightless rails (Aves : Rallidae) from the Middle Pleistocene "crane fauna" of Bermuda

Abstract

Two new species of flightless rails are described from a Pleistocene fauna in Bermuda that also includes an extinct crane (Cnrs latipes) and an extinct duck (Anas pachyscelus). The medium-sized Rallus ibycus, new species, was possibly derived from North American populations of Virginia Rail (R. limicola), but had a longer bill, much more robust legs, and reduced wings and pectoral girdle. The very small Porzana piercei, new species, except for the reduced wing and pectoral girdle, is very similar to the extant Yellow-breasted Crake (P. flaviventer), which now occurs only in the Neotropics, including the Greater Antilles. The fauna that included these rails developed during a long, stable glacial period of lowered sea-levels in the Middle Pleistocene, during which the entire Bermuda platform was emergent. This was followed by an abrupt and extreme interglacial about 400,000 years ago when sea-levels rose to 21 m above present levels, obliterating most of Bermuda and much of its endemic fauna, including the rails.