WWD: Iberomesornis romerali

The small bird that appears in one notable scene mobbing the Ornithocheirus. Because the journey starts in Spain now, I suppose the scene would happen a bit earlier in this version. This was one of the earliest known members of a group of avialans known as enantiornitheans, which were incredibly widespread and diverse during the Cretaceous Period, but became totally extinct alongside all other non-avian dinosaurs at the period's end.

Enantiornitheans differed from modern-type birds in numerous respects (hence their name, "opposite birds"). Many had teeth and clawed wings, while mostly lacking the fan of tail feathers omniscient in modern-type birds (and I've redesigned Iberomesornis without it), but at least one fossil found that some did. Most significantly, enantiornitheans generally followed a drastically different life history; unlike modern birds, which usually reach near-adult size within one year, enantiornitheans were highly precocious, possibly even being able to fly immediately after hatching, and remained juveniles for years, likely occupying different niches than the adults. This sort of growth pattern was widespread amongst pterosaurs and other non-avian dinosaurs, but is virtually non-existent in modern birds and mammals. It is speculated that this slow growth pattern only proved detrimental after the mass extinction, as it took the animals too long to reach breeding age to replenish their numbers after decimation.

The series uses the idea that birds were physiologically superior to pterosaurs and were in the process of outcompeting them during the Cretaceous, in large part due to the apparent scarcity of pterosaur fossils in the last 20 million years of the Mesozoic. However, newer studies have largely refuted these claims, as does the fact that much of what the series presented about pterosaurs has since been found to be incorrect, and this viewpoint, that relied pterosaurs having inferior anatomical features, was built on dubious assumptions to begin with.

It should be noted, the skull of Iberomesornis is as yet unknown, meaning whether it had a toothless beak or not is impossible to tell, as is its diet. Comparisons with other enantiornitheans are difficult, because classifying small birds when they're alive is difficult enough, classifying ones which are known only from fossils, of frequently fragmentary nature, and have no close living relatives is a nigh impenetrable quagmire of taxonomy.