Complex sentence: The long-billed wren was a tiny bird with stout legs, tiny wings, and a reduced sternum, suggesting that it had weak flight muscles and was probably flightless, like the recently extinct Stephens Island wren.
Split into simpler sentences: The long-billed wren was a small bird with stout legs and tiny wings. Its reduced sternum suggests that it had weak flight muscles and was probably flightless, like the recently extinct Stephens Island wren.