Field Guide, Part 4; Pteranodons and Birds

A Field Guide to Fossils of the Smoky Hill Chalk

Part 4: Pteranodons, Birds, and Dinosaurs

Copyright © 2000-2011 by Mike Everhart

Last Updated 01/25/2011

Continued from Part 3: Marine Reptiles

Pteranodons are a group of flying reptiles that are characteristically toothless and tail-less (they do have a short tail). The males grew to large size (wingspreads of 7.5 m or more) during the deposition of the Smoky Hill chalk (Late Coniacian to Early Campanian, 87 to 82 mya). Their remains are only known for certain from Kansas, South Dakota and Wyoming

The wing bones of the first Pteranodon found in North America was discovered in the Smoky Hill Chalk of western Kansas by O. C. Marsh in 1870. The only species of pterosaurs that are known to occur in the chalk are the highly developed Pteranodons and Nyctosaurus.

These flying reptiles do not have teeth or tails like earlier pterosaurs found in the Jurassic of Europe, and are generally much larger.

LEFT: An old version of the skeleton of Pteranodon longiceps (Wing spread about 20 feet) - Upper Smoky Hill Chalk, Kansas. The wing membranes are no longer considered to have been connected to the lower legs.

They were apparently "warm blooded" in some respects, and may have had a thin covering of hair on their bodies. Pteranodons fed primarily on fish and squid. Their role in the Late Cretaceous Inland Sea was probably similar to modern sea birds such as the albatross and pelican, and they may have spent most of their lives soaring over the ocean looking for food.

Nesting sites are unknown in the fossil record of North America but it likely that they were hundreds of miles from where their abundant remains are found in the Smoky Hill Chalk of modern day Kansas.

LEFT: The skeleton of Pteranodon longiceps (lateral view) - Adapted from original drawing by Eaton (1910). Not the relative size of the huge skull compared to the much smaller body.

LEFT: Another version of Eaton's 1910 drawing of Pteranodon longiceps. In this case, the figure is an illustration from: Hankin, E. H. and D. M. S. Watson. 1914. On the flight of Pterodactyls. The Aeronautical Journal, 18: 324-335.

Note the small size of the pteranodon's body compared to the length of the head, and to the wings. Pteranodons were superbly adapted to flight, including their hollow bones and the way in which their dorsal vertebrae were fused together with the ribs to form a solid structure that supported the flight muscles. While they were excellent long distance flyers, they probably spent more time soaring than flapping their wings.

A. Pteranodon longiceps: Pteranodons were first discovered in the upper chalk of Logan County, Kansas by O. C. Marsh in 1870. The only remains found were fragments of wing bones, but they were recognizable as being similar to the pterodactyls found in Europe. Marsh named two species from the remains, Pterodactylus occidentalis and P. ingens. P. longiceps was named later from a much more complete specimen. It wasn't until about 1876 that the first skulls were found and it was discovered that these flying reptiles did NOT have teeth and the name was changed to Pteranodon. It was later realized that nearly all of the remains were probably from the same species, Pteranodon longiceps.

LEFT: The skull of Pteranodon longiceps (lateral view, about 4 feet)

(From YPM-1177)

B. Pteranodon sternbergi -

LEFT: Type specimen of Pteranodon sternbergi (FHSM VP-339) - A large pterosaur, with a wing spread of more than 20 feet which is characterized by a large, upward pointing crest. P. sternbergi is found fairly commonly in the lower chalk. The first specimen was found by G. F. Sternberg in 1952 in Graham County, KS. Fossilized pterosaur remains are extremely fragile, but sometimes include wing and toe claws. Pteranodon remains first occur in the low chalk near Hattin's Marker Unit 5. P. longiceps is a related species that occurs higher in the chalk. The males of this species have long, slender crest that extends almost as far behind the skull as the jaw extends to the front!

LEFT: In 1996, my wife found the wing bones of a large Pteranodon sternbergi eroding from the edge of a chalk bluff. We recovered the skull and most of the wings. In 1999, we donated the specimen (CMC VP 7203) to the Cincinnati Museum Center where it is currently on exhibit. In February, 2003, I visited the museum and took the pictures shown at left.

LEFT: Here are some pictures of the lower leg bones of a small Pteranodon that I found several year ago (Also identified by Chris Bennett)

LEFT: A nearly complete (lacking the humerus) left wing of a Pteranodon collected by G. F. Sternberg and exhibited in the Fick Fossil and History Museum in Oakley, Kansas.

RIGHT: Detail of the same wing showing the three digits of the hand and the cores of the wing claws.

C. Nyctosaurus gracilis -

Nyctosaurus was a smaller pterosaur that occurs from the middle of the chalk upwards. It was first described by O. C. Marsh in 1876. Other than size, the skeleton differs from P. longiceps most noticeably in the shape of the humerus (upper wing bone), and in the lack of a crest on the skull.

LEFT: The type specimen of Nyctosaurus bonneri (FHSM VP-2148) at the Sternberg Museum. Bennett (1994) considered N. bonneri to be a junior synonym of N. gracilis.

	LEFT and RIGHT: The first nearly complete specimen of Nyctosaurus gracilis at the Field Museum of Natural History in Chicago, IL. FM25026 was described by Williston (1902). Found by H. T. Martin in western Kansas. (Photographed in 2003)
	*LEFT: The skull and lower jaw of Nyctosaurus gracilis* (FM25026). This was one of the first pteranodon skulls ever to be photographed for publication (Williston, 1902). RIGHT: The skeleton of FM25026, with labels.**

LEFT: The nearly complete specimen of a Nyctosaurus gracilis (UNSM 93000) from the Smoky Hill Chalk of western Kansas on exhibit in the University of Nebraksa State Museum, Lincoln Nebraska. Found by Greg Brown near Elkader in Logan County. This specimen shows that Nyctosaurus had three wing phalanges, not four as shown in Williston's drawing below.

LEFT: A drawing of the skeleton of Nyctosaurus gracilis from Williston's "Osteology of Reptiles" (1925, p. 299, fig. 190).

Until recently, Nyctosaurus was not known to have crests like the larger species of Pteranodon (see below).

The recent discovery in the Smoky Hill Chalk of western Kansas of two specimens of Nyctosaurus with very large crests is discussed in a paper by Chris Bennett:

Bennett, S. C. 2003. New crested specimens of the Late Cretaceous pterosaur Nyctosaurus. Paleontologist Zeitschrift, 77:61-75. (Chris Bennett Website)

The extremely large crest (at right) on these small flying reptiles raises questions about what it was used for and how they were able to fly.

D. Toothed Birds

There were several species of primitive birds that flew over and / or swam in the Western Interior Sea. A major difference between these and modern birds was that they still had teeth. The bones of Hesperornis are fairly dense and finely grained. Bird remains are relatively rare in the Smoky Hill Chalk.

1. Hesperornithids - Large (5+ ft in length) flightless birds that swam in the ocean and preyed on small fish much like modern penguins. Hesperornis remains are rare, and are found only in the upper chalk (Campanian). Remains of these birds are more common in Cretaceous deposits to the north of Kansas where the weather / water was probably cooler. You can see the remains of a Hesperornis preserved as stomach contents in a large Tylosaurus here.

At right: A drawing of Hesperornis, based on skeletal remains (about 5 feet in length). (Another view HERE)

Hesperornis regalis was a large (up to 5 feet in total length) flightless bird (with teeth) that lived in the northern reaches of the Western Interior Sea. Although the first remains of this bird were found in Kansas in the 1870s, they are more common further north in Canada.

LEFT: This picture of a nesting Hesperornis is from the large seashore mural at the Sternberg Museum. RIGHT: A diving Hesperornis from a large underwater diorama in the Sternberg Museum.

Click on the pictures at right to see portions of the mounted partial skeleton of Hesperornis regalis (FHSM VP- 2069) at the Sternberg Museum of Natural history: 1) neck, chest and hips; 2) hips and upper legs; and 3) left foot.

2. Baptornithids - Smaller, flightless birds similar to Hesperornis and found only in the upper chalk.

3. Ichthyornithids -A small, pigeon or gull-sized bird. Ichthyornis is rare but apparently occurs throughout the chalk. A partial skeleton of a mounted specimen (FHSM VP-2503) of Ichthyornis is on exhibit at the Sternberg Museum of Natural History.

Ichthyornis was first found by Professor B. F. Mudge and described by O. C. Marsh in 1872. Marsh's restoration of the skeleton is at right; the lower jaw is here. Here is a picture of the upper end of a Ichthyornis leg bone (femur). The teeth and manner of replacement was described in: Marsh, O. C., 1883. Birds with Teeth. 3rd Annual Report of the Secretary of the Interior, 3: 43-88. Government Printing Office, Washington, D.C., page 73:

"In the lower teeth of Ichthyornis, the pulp-cavity passes well up into the base of the crown. The fang is compressed, and directed downward and forward. It is firmly set in a deep socket, which it nearly or quite fills. The dental succession took place vertically, as in Crocodiles and Dinosaurs; not laterally as in Hesperornis and the Mosasaurs, a fact of no little significance. The young teeth are much inclined when they first appear above the jaw, after the old teeth have been expelled."

RIGHT: Fig. 27, a reconstruction of Ichthyornis (dispar) victor, from Marsh, 1883. (CLICK TO ENLARGE).

At left: A painting of Ichthyornis sp. in the sea shore mural at the Sternberg Museum of Natural History, based on skeletal remains (about 10 inches). Ichthyornis dispar was a small, gull or tern-like Late Cretaceous bird with teeth. Ichthyornis was first found by Professor B. F. Mudge and described (without teeth) by O. C. Marsh in 1872. Marsh's restoration of the skeleton is here; the lower jaw is here. At right: A mounted partial skeleton at the Sternberg Museum (FHSM VP-2503) found by J.D. Stewart in 1970 (Graham County, near Bogue, KS). For a photograph of a recently discovered Ichthyornis coracoid bone, click HERE.

Bird brains: In these figures from Marsh's (1883) Birds with Teeth: (left) the skull and relative brain size of Ichthyornis victor (Fig.19 ) is compared with the modern Sandwich Tern (Sterna Contac, Fig. 20 ); (right), the skull and relative brain size of Hesperornis regalis (Fig. 7) is compared with with the modern Loon (Columbus torquatus, Fig. 8).

E. DINOSAURS:

The Smoky Hill Chalk is about the last place I would have expected to ever find a dinosaur. Yet the remains of several dinosaurs have been discovered there... the first of which was found by Professor O. C. Marsh in 1871 in Logan County.

LEFT: The mounted type specimen of Claosaurus agilis (YPM 1190) in the Yale Peabody Museum. This specimen is reasonably complete but somewhat weathered. According to Marsh, he went back to the site at least once to recover more of the remains. The skull was missing from the remains and is a plaster model in this mounting.

After that, two sets of fragmentary nodosaur remains (dermal scutes) were discovered by Charles Sternberg and called Hierosaurus sternbergi by Wieland in 1909. The best specimen, however, is a reasonably complete nodosaur (Ankylosauridae) called Niobrarasaurus coleii. It was found by an oil field geologist doing surface mapping of Gove County in 1930. It was only the fourth set of dinosaur remains to be found in the chalk... the first three were found by O. C. Marsh and Charles Sternberg.

LEFT: Additional pieces (foot bones) of the type specimen of Niobrarasaurus coleii found by Tom Caggiano in May, 2003.

Since 1930, two additional partial nodosaur remains have been found in the Smoky Hill Chalk. The first was specimen discovered by by J.D. Stewart in Rooks County (1973), and the second was a juvenile limb found by Shawn Hamm in Lane County in 2000 (pictured).

RIGHT: The right ulna of VP-13985 compared to the type specimen of Niobrarasaurus coleii.

LEFT: The right radius of VP-13985 compared to the type specimen of Niobrarasaurus coleii.

LEFT: On June 2, 2005, I was with Keith Ewell when he found what is only the sixth set of dinosaur remains to be documented from the Smoky Hill Chalk of western Kansas. The newest dinosaur specimen from the Smoky Hill Chalk consists of nine articulated caudal (tail) vertebrae (FHSM VP-15824) from an adult hadrosaur. The most anterior (light colored) vertebrae (#1 and #2) of the series had eroded out and were exposed on the surface of the chalk. The other seven vertebrae were still completely enclosed in the matrix. The specimen is 22 in (55 cm) in length, and comes from the distal part of the tail. There are non-serrated bite marks on both sides of the last vertebrae (#9, see pictures below). The bone surface at both ends of the articulated series are severely eroded and appear to have been partially digested.

EIGHTH DINOSAUR SPECIMEN FOUND IN THE SMOKY HILL CHALK (FHSM VP-17229)

LEFT: Over the Memorial Day weekend in 2007, Laura and Scott Garrett were prospecting for fossils in the lower Smoky Hill Chalk (below Hattin's Marker Unit 3 - Late Coniacian) of southwestern Trego County. Laura found an isolated anterior caudal vertebra (near the base of the tail) from what appears to be a large ankylosaur, most likely Niobrarasaurus coleii. Note that this vertebra is very similar to, but much larger than, the one collected by Keith Ewell in 2004 (above). Laura becomes the first woman (and only the 7th person) to ever collect dinosaur remains from the Smoky Hill Chalk. The Garretts generously donated the specimen to the Sternberg Museum of Natural History (VP-17229). The specimen comes from about 6 miles south of the site where VP-16385 was collected in 2004, and from about 5 miles east of where the type specimen of Niobrarasaurus coleii (VP- 14855) was collected in 1930. All are Late Coniacian in age.

CONTINUE TO PART 5: COPROLITES, Coprolites, Pearls, Fossilized Wood and other Remains

For additional background information on Kansas geology, Smoky Hill Chalk, marine fossils of the Late Cretaceous and paleontology in general, see my Late Cretaceous Marine references about Marine reptiles and Fish and other fossils.

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