Skip to main content

Hand and foot morphology maps invasion of terrestrial environments by pterosaurs in the mid-Mesozoic

Hand and foot morphology maps invasion of terrestrial environments by pterosaurs in the mid-Mesozoic

NEWS - Pterosaurs, the first true flying vertebrates, played a significant role in Mesozoic terrestrial ecosystems from about 252–66 million years ago. However, our understanding of their ability to move on land more broadly and their terrestrial paleoecology is limited.

The researchers show a remarkably high degree of variation in pterosaur hands and feet, comparable to that observed in birds today, suggesting that pterosaurs adapted to a wide range of non-aerial locomotor ecologies throughout history.

Early small-bodied, long-tailed (non-pterodactyliform) pterosaurs exhibited extreme modifications in hand and foot proportions indicative of a climbing lifestyle. In contrast, the hands and feet of short-tailed (pterodactyliform) pterosaurs typically exhibit morphology consistent with a more terrestrial locomotor ecology.

"Early pterosaurs were highly specialised for climbing with modifications to their hands and feet, similar to today's climbing lizards and woodpeckers. Holding on to a vertical surface using the fingertips for long periods of time is a difficult task, much easier for small, light animals," says Robert Smyth of the University of Leicester.

This change in proportions correlates with other modifications to pterosaur anatomy, in particular, the separation along the midline of the flight membrane (cruropatagium) that connected the hind limbs and enabled much more effective locomotory abilities on the ground.

Together, these changes map out a key event in tetrapod evolution in the mid-Mesozoic colonisation of terrestrial environments by short-tailed pterosaurs.

"The hind limbs connected by a flight membrane would have constrained walking and running in early pterosaurs. In more advanced pterosaurs, this membrane separated along the midline allowing each hind limb to move independently," says David Unwin of the University of Leicester.

"This was a major innovation that, combined with changes to their hands and feet, greatly increased the mobility of pterosaurs on land. Freed from the constraints of climbing, these later pterosaurs could grow to enormous sizes, with some species becoming true giants in the Mesozoic," says Unwin.

This transition to a predominantly land-based locomotory ecology did not occur as a single event coinciding with the origin of short-tailed forms, but evolved independently in each of four major radiations: euctenochasmatians, ornithocheiroids, dsungaripteroids and azhdarchoids.

The invasion of terrestrial environments by pterosaurs facilitated the evolution of a wide range of new feeding ecologies, while freedom from the constraints imposed by climbing allowed the increase in body size that ultimately enabled the evolution of gigantism in a range of lineages.

"This finding underscores the need to study all aspects of pterosaurs, not just flight. Pterosaur flight is only one part of their story. By studying how they lived in trees and on the ground, we can begin to understand the role they played in ancient ecosystems," Smyth said.

Original research

Smyth, Robert S.H. et al. (2024). Hand and foot morphology maps invasion of terrestrial environments by pterosaurs in the mid-Mesozoic. Current Biology, DOI:10.1016/j.cub.2024.09.014

Dlium theDlium
Labels:

Popular Posts

Sea almond (Terminalia catappa)

Ketapang or tropical almond or beach almond or talisay tree or umbrella tree or sea almond ( Terminalia catappa ) is a species of plant in the Combretaceae, a shady tree, fast growing, forming a multilevel canopy, often used as a shade tree in gardens and on roadsides. T. catappa grows large, up to 40 meters in height and up to 1.5 meters in trunk, shady canopy with branches that grow flat and terraced, young trees often look like pagodas while old and large trees often have aerial roots up to 3 meters. The leaves are scattered, mostly at the end of the twig, rounded egg upside down, 8-38 cm long, 5-19 cm wide, the tip is wide, the base is narrow, the upper surface is smooth, green but turns red if to fall out and short stalks. The flowers are small, collected near the tips of the twigs, 8-25 cm long and green-yellow in color. The flowers are not crowned, the petals have five taju, are plate or bell shaped, 4-8 mm long and are white or cream in color. Stamens in two circles and arra...
Read more

Purple nutsedge (Cyperus rotundus)

Teki or purple nutsedge ( Cyperus rotundus ) is a species of plant in the Cyperaceae, an erect annual growing to a height of up to 140 cm, the leaves sprout in rows of three from the base to a length of 5-20 cm, ribbon-shaped, pointed tip and green in color. The inflorescence has a stalk with a triangular cross section and is green. The inflorescence has three to eight unequal spikes. The flower is bisexual, has 3 stamina and the pistil has three stigmas. The fruit is achene and triangular. Teki prefers dry places, but will tolerate moist soil and often grows in wastelands and in crop fields. Tubers are an important source of nutrition for migratory cranes. Source of carbohydrates in the tropics in times of famine. The initial stage forms a white fleshy rhizome, 25 mm long and in chains. Some of the rhizomes grow upright above the ground, then form a tuber-like structure from which new shoots and roots grow, new roots and new rhizomes grow. Other rhizomes grow horizontally or down...
Read more

Asian foxtail (Uraria crinita)

Asian foxtail or cat's tail bean ( Uraria crinita ) is a species of plant in Fabaceae, a perennial, upright shrub with woody stems at least at the base, up to 2 meters high in forests, agricultural land, waterways, used as a medicinal herb, green manure and sometimes planted in the garden as an ornamental plant. U. crinita has elongated leaves, rounded base, pointed tip, a bone in the middle with several pinnate veins, rough surface, dark green with white spots. Petiole short or less than 0.5 cm and brownish red. Compound flower in spike shape, purple and white triangular crown. Long flower stalk, erect, 15-20 cm long and only at the end of the flower. The crown slowly falls off and leaves behind a stalk that is shaped like coir or light yellow pads. Asian foxtail grows in dry grasslands, open forests, trash cans, roadsides, sandy areas and sometimes in deciduous forests, elevations of 0-1500 meters and does not grow in waterlogged places. The different parts are often used in t...
Read more