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Baptornis advenus

Marsh 1877

Toothed marine birds of the Late Cretaceous seas

Copyright © 2008-2017 by Mike Everhart

Page created 10/27/2008 - Last updated 03/02/2017

LEFT: An artist's reconstruction of Baptornis advenus, adapted from Martin and Tate (1976, Fig. 20).  Original artist, B. Dalzell (3-1965).   Martin and Tate also noted that the digits of the feet were probably "lobed" and not webbed as shown

Baptornis advenus Marsh 1877

Baptornis (from the Greek, literally meaning "diving bird") is an extinct genus of flightless marine birds from the Late Cretaceous. Although the first hesperornithiform birds (Enaliornis sp.) are known from the latter part of the Early Cretaceous in England, the first known Baptornis remains come from  Santonian age (roughly 85 million years ago) rocks of western Kansas. The type specimen of Baptornis advenus, fragments of a single bone called the tarsometatarsal, were discovered in the Smoky Hill Chalk in Logan County, Kansas by O.C. Marsh’s collectors, most likely during the 1877 field season. Other, partial specimens are in the collections of the Field Museum of Natural History, and the University of Kansas Museum of Natural History.  One of the best specimens was collected by G.F. Sternberg in the 1930s and acquired by the University of Nebraska State Museum (UNSM 20030 – Shown below).

Somewhat more primitive and about half the size of Hesperornis, the 1 m (~3 ft 4 in) Baptornis had lost the ability to fly (IF it's ancestors had flown?), and possessed only vestigial wings (upper limbs). However, unlike Hesperornis, all of the wing bones were still present, although greatly reduced in size. Baptornis swam with its large legs and feet that had long, widely spaced toes. It is uncertain if the toes of Baptornis were webbed as in Loons and ducks, or lobbed as in modern Grebes and Hesperornis.  The bones of Baptornis were heavy, unlike the light, hollow bones of most flying birds. This helped Baptornis and other hesperornithiforms in diving and swimming underwater by reducing its buoyancy. Although the skull is still unknown, like other hesperornithiforms, Baptornis probably had teeth on its beak to help it catch fish and other prey. The unusually long neck of Baptornis would also have been advantageous in acquiring food. 

Marsh1877-Baptornisa.jpg (22921 bytes) LEFT: In 1877, O.C. Marsh described Baptornis advenus, a new genus and species of hesperornithid on the basis of a "nearly perfect [right] tarso-metatarsal bone," noting that it was distinct enough from Hesperornis to justify a new species. Since then, however, Schufeldt (1915, p.9) noted that the [less than perfect] specimen more likely represents the opposing ends of similar bones from two different individuals, and Martin and Tate (1976) indicated that the Yale Peabody Museum had given a separate number to each portion (YPM 1465 (distal) and YPM 5768 (proximal)). The specimen was collected by G.P Cooper in Gove County on July 4, 1876. It seems highly unlikely that the two pieces came from two different individuals collected on the same day.... when bird bones of any kind are extremely rare in the the Smoky Hill Chalk.

RIGHT: Marsh's figure of the tarsometatarsus of Baptornis advenus was published in 1880. Baptornis was smaller and possibly more primitive than Hesperornis. It also occurs earlier (Santonian) in the Smoky Hill Chalk than does Hesperornis (Campanian).

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"The existence of a small swimming bird contemporary with Hesperornis is indicated by a nearly perfect tarso-metatarsal bone from the same geologic horizon." Marsh (1877, p. 86)

In terms of the number of known specimens, Baptornis advenus is one of the better known birds from the Late Cretaceous after Hesperornis regalis and Ichthyornis dispar. It was first described by O. C. Marsh (1877) as a new genus closely allied with Hesperornis.  It is readily distinguishable from Hesperornis by its smaller size and certain characters of the foot (Martin and Tate, 1976).

LEFT:  Skeletal reconstruction of Baptornis advenus, adapted from Martin and Tate, 1976, Figure 19)

RIGHT: Two views of the right foot of Baptornis advenus (UNSM 20030, adapted from Martin and Tate, 1976, Figure 17).

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UNSM20030-Baptornisa.jpg (13511 bytes) LEFT: A fairly complete skeleton of Baptornis advenus (UNSM 20030) collected by G.F. Sternberg and acquired by the University of Nebraska State Museum in 1937. The skeleton includes vertebrae, ribs, uncinate processes, wing bones, half of the pelvis, and most of both rear legs, and feet, as well as preserved intestinal contents (colonites).

In George F. Sternberg's "Field List" for 1936, he described his SP (specimen) 101-36 as: "Bird, Hesperornis regalis. HORIZON: Cretaceous chalk. LOCALITY: About 22 miles southeast of Oakley, northeast 1/2 mile of the Maston? house.  DESCRIPTION: What appears to be the greater part of both feet, vert., limb bone, ribs and other elements. A very small ind. In shale rock. 1- plastered section. All fragments in section."  A handwritten note on the same page  indicates that he later "Opened and prepared" the specimen.. and regarded it as "Choice."

Recent (2008) photographs of the remains are shown below.

UNSM20030-Comparea.jpg (15701 bytes) LEFT: Comparative sizes of the tarsometatarsals, the fibulae and the right femur of the UNSM 20030 Baptornis advenus specimen.

RIGHT: Part of the slab containing ribs and uncinate processes of UNSM 20030. (For more information, see Figs. 7 and 8 of Martin and Tate (1976)

UNSM20030-Ribsa.jpg (24964 bytes)
UNSM20030-RtFemura.jpg (14465 bytes) LEFT: Anterior and posterior views of the right femur of UNSM 20030.

RIGHT: A lateral view (upper) and medial view (lower) of the right half of the pelvis of UNSM 20030. The right and left halves would have been joined by the sacrum.

UNSM20030-RtPelvisa.jpg (26532 bytes)
UNSM20030-Fibiaea.jpg (18107 bytes) LEFT: Anterior and posterior views of both tibiotarsi of UNSM 20030.

RIGHT: Anterior and posterior views of both fibulae of UNSM 20030.

UNSM20030-Tibulaea.jpg (13215 bytes)
UNSM20030-TMTa.jpg (15343 bytes) LEFT: Anterior and posterior views of both tarsometatarsals of UNSM 20030. These bones represent a fusion of the "ankle" bones found in mammals.

RIGHT: Tarsal (toe) bones of UNSM 20030. See the original photo (above) by G.F. Sternberg for the their placement.

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UNSM20030Vertebrae2a.jpg (14297 bytes) LEFT: Four vertebrae from of Baptornis advenus (UNSM 20030), mostly in end view.

RIGHT: Vertebrae from of Baptornis advenus (UNSM 20030) in various orientations; from a specimen collected by G.F. Sternberg.

UNSM20030Vertebraea.jpg (21667 bytes)
UNSM20030Colonitea.jpg (15482 bytes) LEFT: "Included with UNSM 20030 are eight coprolites, two of which show small fish jaw and other bones. Most are round or elliptical in cross-section and are elongate, except for the two containing fish material. None shows spiral grooving or surface impressions. George Sternberg, the collector, in a 1937 communication preserved in the records of the University of Nebraska State Museum [UNSM], makes the following reference to the association of these coprolites with Baptornis skeleton:  "There are 7 or 8 coprolites ... 2 show small fish bones. These are small compared to the other coprolites I have seen and were found mingled with the bones." It seems likely that these coprolites are correctly associated with the Baptornis skeleton; if so, they are the only ones known for a Cretaceous bird. However, several of them fit together to for a long rounded structure that might be better interpreted as an intestinal cast. The jaw in one coprolite [RIGHT] was identified by Orville W. Bonner of the University of Kansas (pers. comm., 1972) as Enchodus cf. parvus." (Martin and Tate, 1976, Figure 22)    UNSM20030Colonite-jawa.jpg (19685 bytes)

Baptornis varneri Martin and Cordes-Person, 2007

This new species of Baptornis was described by James Martin and Amanda Cordes-Person from a specimen discovered some years ago by Dan Varner in the Pierre Shale of western South Dakota.

Martin, J. E. and Cordes-Person, A. 2007. A new species of the diving bird Baptornis (Ornithurae: Hesperornithiformes) from the lower Pierre Shale Group (Upper Cretaceous) of southwestern South Dakota. The Geological Society of America, Special Paper 427: 227-237.


"Fossil birds are relatively rare in Cretaceous deposits of the Northern Great Plains, so the discovery of a large, new diving bird was unexpected. From marine deposits of the Niobrara Formation in Kansas small diversity of birds was known, but until now the large diving bird, Hesperornis was the only bird taxon known from the Pierre Shale Group of South Dakota. The new discovery, a partial skeleton of another diving bird, Baptornis, was secured from the Sharon Springs Formation (lower middle Campanian) of the Pierre Shale Group in Fall River County, South Dakota. The specimen is represented by vertebrae, pelvic fragments, and lower leg elements that are similar to but much more robust than Baptornis advenus from the subjacent Niobrara Formation. The new taxon is nearly twice the size of the Niobrara species, principally in robustness rather than in length of elements. Overall, the specimen represents the first occurrence of Baptornis from the Pierre Shale Group, represents a new species, and indicates greater diversity of birds from the Pierre Shale Group than was previously known."

Etymology: Named for Daniel Varner who found the specimen, and for his notable contributions to paleontology in the form of artistic renderings of extinct vertebrates.


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