[2] Nyctosaurus was a mid-sized pterosaur that lived along the shores of the Niobrara Formation of the United States, which back then was within a large inland sea called the Western Interior Seaway.

It has been suggested that it would have flown similar to modern-day soaring birds such as albatrosses, which consisted of flying very long distances and rarely flapping.

The first Nyctosaurus fossils were described in 1876 by Othniel Charles Marsh, based on fragmentary material, holotype YPM 1178, from the Smoky Hill River site in Kansas.

[4] Later that year, Marsh reclassified the species in its own genus, which he named Nyctosaurus, derived from the Greek νύξ (nyx, "night") and σαῦρος (sauros, "lizard").

This species has an estimated wingspan of four metres; today, it is generally considered to be a form different from Nyctosaurus, but has not yet been assigned its own genus name.

Despite being in private hands rather than a museum collection, paleontologist Chris Bennett was able to study the specimens and gave them the manuscript reference numbers KJ1 and KJ2 (for Kenneth Jenkins).

[14] Some skull specimens preserve a distinctively large crest, at least 55 centimeters (1.80 ft) tall in the older adults, and was relatively gigantic compared to the rest of the body, while also being over three times the length of the head.

[15] As a result, it was likely to have impaired its movement on the ground, leading scientists to conjecture that it spent almost all of its time on the wing and rarely landed.

In particular, the lack of claws with which to grip surfaces would have made climbing or clinging to cliffs and tree trunks impossible for Nyctosaurus.

Analyses show that Nyctosaurus had the shortest hindlimbs of any pterosaur genera, in terms of hindlimb-to-body ratio, at only around 16 percent the size of its wing.

[16] Muzquizopteryx coahuilensis "Nyctosaurus" lamegoi Nyctosaurus gracilis Alamodactylus byrdi Pteranodon longiceps Pteranodon sternbergi Longchengpterus zhaoi Nurhachius ignaciobritoi Liaoxipterus brachyognathus Istiodactylus latidens Istiodactylus sinensis Lonchodectes compressirostris Aetodactylus halli Cearadactylus atrox Brasileodactylus araripensis Ludodactylus sibbicki Ornithocheirae In 2018, a topology by Nicholas Longrich and colleagues had made the clade Pteranodontoidea the more inclusive group, while Pteranodontia was restricted to only pteranodontids and nyctosaurids.

[2] A few scientists had initially hypothesized that this crest, which resembles an enormous antler, may have supported a skin "headsail" used for stability in flight.

While there is no fossil evidence for such a sail, studies have shown that a membranous attachment to the bony crest would have imparted aerodynamic advantages.

[3] However, in the actual description of the fossils, paleontologist Christopher Bennett argued against the possibility of a membrane or soft tissue extension to the crest.

Specifically, they are found only within a narrow zone characterized by the abundance of ammonite fossils belonging to the species Spinaptychus sternbergi.

These limestone deposits were laid down during a marine regression of the Western Interior Seaway that lasted between 85 and 84.5 million years ago.

In the waters of the Western Interior Seaway below swam mosasaurs such as Clidastes, Ectenosaurus, Eonatator, Halisaurus, Platecarpus and Tylosaurus, several remains of the plesiosaurs Dolichorhynchops and Polycotylus, cephalopods like Baculites and Tusoteuthis, and the sea turtles such as Ctenochelys and Toxochelys were also found.