Valentine and Ash Hollow formations, Nebraska
Painted 1964
Acrylic on canvas; 12 ft., 1 in. H × 18 ft., 9 in. W
Valentine and Ash Hollow formations, Nebraska
Painted 1964
Acrylic on canvas; 12 ft., 1 in. H × 18 ft., 9 in. W
Clarendonian Land Mammal Age, 12.5 to 9.4 million years ago
1 · Populus (cottonwood)
2 · Aphelops (rhinoceros)
3 · Torynobelodon (Amebelodon; shovel-tusked elephant)
4 · Teleoceras (short-legged rhinoceros)
5 · Megatylopus (giant camel)
6 · Pliohippus (one-toed horse)
7 · Procamelus (camel)
8 · Synthetoceras tricornatus (protoceratid)
9 · Neohipparion (three-toed horse)
10 · Hemicyon (dog-bear)
11 · Cranioceras (dromomerycid)
12 · Prosthennops (peccary)
13 · Pseudaelurus (cat)
14 · Ceratogaulus (Epigaulus; horned rodent)
15 · Merycodus (pronghorn)
16 · Hypolagus (rabbit)
17 · Borophagus (Osteoborus; bone-crushing dog)
Ceratogaulus (called Epigaulus at the time of the mural’s creation) was a digging, or fossorial, rodent, as shown by its large claws. It was similar to modern gophers and prairie dogs but not closely related to either one. Its unusual paired nose horns are unique among rodents, and it is thought that the animal used them for defense. Though it was large for a burrower (about 2 pounds, the size of a marmot), it is the smallest known horned mammal.
The Miocene dog Borophagus had large jaw muscles and crushing teeth (evident in the skull at right) that were capable of cracking open bones. It was thus similar to today’s hyenas, which evolved independently from Borophagus and are more closely related to cats. The pair here is shown working on the carcass of the camel Procamelus (see this page).
Teleoceras was a short-legged, stout, single-horned rhinoceros. Usually described as hippolike, it actually may have been primarily a land dweller. Many dozens of nearly complete skeletons of the species have been found. The three study drawings on this page show Matternes’s regular strategy of building up a fully fleshed-out reconstructed animal from a museum skeleton (in this case, he studied one from the AMNH).
Gomphothere elephants were common in Miocene North America, and often categorized by the presence of both upper and lower tusks. Originally labeled Amebelodon, the mural shows an animal with broad, flat, “shovel tusks” that actually characterize the related Torynobelodon. Matternes depicted it with a flattened trunk, in line with scientific thinking of the time. But the study drawing (opposite) is probably more accurate in showing a rounded trunk like that of modern elephants.
Miocene horses came in a wide variety of forms, including three-toed Neohipparion (below right)—a member of a successful lineage that nonetheless left no living descendants. One-toed Pliohippus (right), in contrast, was closely related to modern horses. Matternes placed the two in close proximity (below) so that their differences would be easier for the viewer to spot.
Matternes detailed the important anatomical distinctions between the horses Neohipparion (left) and Pliohippus (above) in these sketches; note especially the different body proportions. The top image is unusual for its use of colored pencil and translucent overlays.
The cat Pseudaelurus stalks slowly forward, perhaps waiting to steal a mouthful from the dog-guarded carcass of Procamelus (see this page). Matternes based this reconstruction on modern cat species, although Pseudaelurus had somewhat shorter legs than today’s big cats. Recent study of Pseudaelurus specimens from this time suggest that they may actually belong to the genus Hyperailurictis.
The second species of late Miocene rhinoceros, Aphelops, was very different in appearance and habit from Teleoceras (see this page). Longer-legged and hornless, Aphelops was more of a browser than a grazer. It could reach enormous sizes, exceeding 7,000 pounds, considerably larger than any living rhino.
Although rather doglike in appearance, Hemicyon was actually more closely related to bears, hence its nickname, “dog-bear.” The feet were digitigrade—meaning the animal walked on its toes—and Matternes highlighted this particular feature in the animal’s pose. Details of the teeth are also made clear.
In these study drawings, note that Matternes shows the missing skeletal elements of Hemicyon in blue (top)—including the long tail, which is now thought to have been short. Matternes ultimately made it short in the final mural, too.
North American pronghorn are not true antelopes but belong to their own family, Antilocapridae, which excludes numerous extinct species. Matternes’s study drawings of Ramoceras (this page) indicate that he elevated the forelimbs and exposed “more of the brisket,” as he noted (below left). The deerlike, but asymmetrical, antlers of Ramoceros were shed each year, unlike the permanent, smaller horns of Merycodus (opposite).
The giant camel Megatylopus (called Gigantocamelus at the time) is readily distinguished from its smaller, and mostly earlier, relative Procamelus (below). The giant camel’s long, flat head is evident in the skull sketch (opposite, top). The study drawing (opposite, bottom) shows an animal whose behavior in the mural was inspired by that of modern camels, and whose stance the artist modeled on Eadweard Muybridge’s groundbreaking animal photography.
The palaeomerycid Cranioceras vies with Synthetoceras (this page) for the title of most bizarre Miocene ungulate. A pair of horns over its eyes was accompanied by a single third horn projecting from the back of its head—a feature unknown in living mammals. The individual in the mural is shown nibbling an itch on its leg.
In his study drawings, Matternes sketched even the cross-section of Procranioceras’s horns (the small shapes positioned alongside them in the drawing above) so that he could more accurately capture their three-dimensional shape. Other details, such as fur texture and leg tendons, are also apparent (left).
Synthetoceras is among the most bizarre mammals in this scene. Only males developed these extreme, slingshot-shaped nose horns, which may have been used in competitions for mates. A member of the protoceratids, a now-extinct group of hoofed mammals, it was perhaps most closely related to camels. Matternes based the animal’s varied fur textures on those of the modern pronghorn.
The landscape of the middle–late Miocene mural looks markedly modern; the artist depicts a scene that could easily be spotted in Nebraska and the Dakotas today. Gallery forests of Plains cottonwood (Populus), hackberry (Celtis), ash (Fraxinus), and willow (Salix) flank the river in the mural’s distance (right), while a short-grass prairie covers the adjacent plains (below).
At the time Matternes painted this mural, little was known about the fossil vegetation of the Plains. His notes show that he consulted the work of Maxim Elias, whose 1936 scientific monograph was one of the first to analyze the sparse record of fossil grass-seed coats and began to build the story of grassland evolution during the Miocene.
These lovely sketches of middle-late Miocene mammals are almost gestural, showing just enough detail to identify each species and distinguish it from similar animals (compare the two horses Pliohippus and Neohipparion shown here, for example, with their more detailed renditions on this page). Matternes clearly based his Ceratogaulus (labeled Epigaulis in this sketch) on the Smithsonian’s exhibit skeleton.
