Curved claws hint at pterosaur habits. (Paleobiology).A study of the claws of ancient flying reptiles known as pterosaurs This list of pterosaurs is a comprehensive listing of all genera that have ever been included in the order Pterosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium suggests that some of the creatures may have walked like present-day herons and used claws on their wings to hold prey. In modern birds Modern birds (subclass Neornithes) are the members of class Aves that have survived into recent times and have coexisted with humans. Modern birds are characterised primarily by their toothless beaks, as most prehistoric bird groups possessed teeth. , claw curvature is closely correlated with the animal's behavior, says David A. Krauss, a paleobiologist at Boston College Boston College, main campus at Chestnut Hill, Mass.; coeducational; Jesuit; est. and opened 1863. Actually a university, the school's Chestnut Hill campus comprises colleges of arts and sciences and business administration, the graduate school, and schools of nursing . Birds that cling to Verb 1. cling to - hold firmly, usually with one's hands; "She clutched my arm when she got scared" hold close, hold tight, clutch hold, take hold - have or hold in one's hands or grip; "Hold this bowl for a moment, please"; "A crazy idea took hold of and climb the sides of trees, like woodpeckers and nuthatches, have strongly curved claws. Birds that walk on the ground, like shorebirds, have relatively straight claws. Perching birds have claw curvature that lies between that of walkers and climbers, Krauss notes. Pterosaurs had claws both on their feet and on their wings. An analysis of more than 100 museum specimens shows that the curvature of claws on pterosaurs' wing fingers was, on average, comparable to that of perching birds. Claws on the pterosaurs' feet, however, were almost straight, like those of birds that walk on the ground. This combination hints that pterosaurs didn't live in trees, says Krauss. Scientists have long debated whether pterosanrs walked bipedally as people do or scrabbled scrab·bled adj. Covered with sparse vegetation; scrubby: "We can stand . . . and look out toward the scrabbled, snow-covered mountains in the west" Russell Banks. along the ground on all fours as bats sometimes do. Krauss and his colleagues contend that pterosaurs walked upright but used their curved wing claws to hold prey steady while they consumed it. Such a technique would have helped prevent wriggling meals from snapping off the pterosaur's delicate teeth.--S. P. |
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