The real surprise, though, came when researchers realized that Alnashetri wasn’t a highly specialized, late-stage Alvarezsauroid. Instead, despite living in the Late Cretaceous, it occupied an early-branching position among earlier, basal members of the clade.
This combination of tiny size and early-branching status fundamentally breaks our previous model of how these animals evolved. If the miniaturization of Alvarezsauroids was strictly tied to their lifestyle as stubby-armed insect-eaters, an early-diverging species like Alnashetri should have some transitional features on a steady, clade-wide march toward that extreme endpoint. But it didn’t look that way.
“It’s a very long-limbed animal, so it was probably fairly fast. My best analogy would be something
→ Continue reading at Ars Technica