Species that Don't Get Enough Publicity #12: Barylambda

The Field Museum is home to many holotypes-Brachiosaurus, the Southwestern species of Parasaurolophus, Cryolophosaurus, Cacops, Secernosaurus, Varanops and Thylacosmilus (more on them later). However, one prominent specimen is a complete skeleton that puzzles visitors and scientists alike. It’s the first thing visitors see exiting the theater that in turn exits from the dinosaur hall. It’s mounted next to the tusked skulls of Coryphodon and Eobasileus in a glass case, facing across from another showing extant orders of mammals under Charles Knight’s depiction of Uintatherium and Orohippus.  It’s been displayed outside the exhibit on the gallery, and when Life Over Time opened in 1992, the mount was heralded, like the others, by a colorful circus banner by Glen C. Davies. I distinctly remember the hairy mammal in a boxer’s robe and gloves, raising his first Ali-style over a fallen dinosaur in the ring, a symbol of mammalian success as the dinosaurs fell to the mass extinction. This is Barylamdba.

Bryan Patterson of the Field Museum had followed Elmer Riggs on many expeditions to Colorado in the 1910s and 20s, and so when Riggs decided to focus on South American material instead in the 1930s, Patterson continued Riggs’ work in Colorado. So, near Grand Junction, off what is now a stretch of Highway 65 between the Colorado River and the Jerry Creek reservoirs, Patterson prospected near where Othniel Marsh, Edward Cope, and Joseph Leidy had worked on Paleocene mammals. In Mesa County he had found many specimens of the primitive ungulate Phenacodus, the huge strange bearlike browser Titanoides, and the small predator Paleonictis, This time in 1933, Patterson found another big browser, bigger than anything else in the Debeque Formation. He named it Titanoides faberi, assuming it to be another variation on the original creature.

After many years of collecting material from this new animal and many relatives, Patterson did an assessment on his big primitive browsers-the creature from Colorado was not Titanoides, but a new species. He named it Barylambda, literally “heavy L”. The L probably refers to the lambdoid suture in mammalian skulls, which is very prominent and thick in the skulls diagnosed. The species name for it was faberi, probably after Charles L Faber, an expert in the Paleozoic oceans of the Midwest from the 19^th century.  

Barylamdba is a pantodont cimolestid, two groups that have been extinct since the Eocene. Cimolestids were a non-placental group of mammals appearing in the late Cretaceous as small rodentlike critters in North America. In the Paleocene, they seized their opportunity and burst into a huge diversity of herbivores with large teeth. The shrewlike Palaeoryctes hunted insects in the jungles of what is now Wyoming and Colorado, the dog-sized Stylinodon and Psitaccotherium dug up roots with their big claws and devoured them with their giant incisors. Another bigtoothed cimolestid was Trogosus, weighing up to 300 lbs and chomping through the woody undergrowth for starchy tubers. A small Cimolestid was the arboreal Kopidodon from Germany’s Messel Pit, having a squirrellike anatomy with the strange addition of big fighting canines
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The biggest and most successful Cimolestids were the Pantodonts, reaching big sizes early. Unlike other cimolestids, they were browsers, covering the globe; they traded in the kin’s buckteeth for high-crowned molars and hippo-like tusks.  The first huge pantodont was the aforementioned Titanoides, found by the American Museum in 1917, a flat footed bearlike tusker. After Titanoides came Barylamdba, the gorilla-sized type specimen being succeeded by specimens the size of ponies and grizzly bears. Barylamdba had two similar kin, Leptolambda and Haplolambda.

The head of Barylambda is long and low, with a flaring nose. The titular suture is large and forms a nuchal crest like that of most ungulate. This animal was reaching its neck up and using its large nose and forward placed, horizontally facing eyes to seek food. The teeth are large, high and pointed; browsing teeth for crushing leaves and branches.

The radius and ulna are huge, and the olecranon and radial head project out. This animal had huge elbows. The feet are broad, with flat hoofed toes like that of a hippo. This suggests that Barylambda also lived in wetlands, an ecology suggested by the surrounding rocks. The late Paleocene was part of the Paleogene thermal maximum, when the earth was mostly a tropical rainforest with huge lakes and rivers and swamps across the northern hemisphere.

The hind limbs are similar, albiet with smaller hind feet and shorts tibia and fibula with a huge femur. What really is interesting is the huge pelvis; it resembles that of a gorilla. The neck, head, and rear half suggest this animal was rearing up frequently to feed. The limbs resemble that of Moropus and other chalicotheres, and the body shape is similar to that of a giant sloth, albiet with larger teeth and without claws. Indeed, the long, strong tail, so unique in large mammals, way probably used to help the hind limbs as a sturdy tripod.

This body shape of Barylambda, chalicotheres, and ground sloths shows a great deal of mammalian convergent evolution. The lifestyle is still found to some extent today-bears have very different anatomy but eat vegetation in the same way, and the folivorous gorilla has already been mentioned. Rear up, stick your head into the foliage, and eat. Not being a ruminant, Barylamdba could have only been a hindgut fermenter, using the size of its stomach to store huge quantities of food to slowly digest.

Barylambda is found in the DeBeque formation of Colorado, in an age called the Clarkforkian in North America. Barylamda appeared only 10 million years after the extinction of the large dinosaurs, and B. faberi was already 400 lbs and only getting heavier as time went on. Barylambda shared its habitat with early representatives of extant animals- the lemurlike primates Chiromyoides and Plesiadapis, the early rodent Franimys, small tusked ungulate Phenacodus and rodentlike kin Haplomylus, Aletodon, Ectocion, and primitive carnivoran Didymictis. It also shared its habitat with other extinct groups, like the fellow Pantodonts the extremely similar Haplolambda, the tusked Titanoides and the hippolike Coryphodon (which would replace Barylambda itself), fellow Cimolestids like the bigtoothed burrowing Taeniodont Ectoganus, the rodentlike Tillodont Esthonyx, and the squirrellike multituberculates (a group dating from the Mesozoic) Ptilodus and Neoliotamus, the primitive insect-eating Lepticid Prodiacodon, and the small arctocyonids (omnivorous bear-racoonlike mammals) Mimotricentes, Chiracus, and Thryptacodon. The Pantodonts lived alongside their larger replacements, the odd horned and tusked herbivore Uintatheres, represented here by Probathyopsis. Predators incuded the crocodile Leidysuchus, bearlike creodont Paleonictis, and doglike mesonychid Dissacus.

More blogs on Barylambda include https://www.fieldmuseum.org/science/blog/seeing-double-how-field-museum-makes-fossil-casts,  https://tanystropheus.wordpress.com/2010/06/19/weekly-spotlight-barylambda/, http://spinops.blogspot.com/2016/01/barylambda-faberi.html

John Conrad Hansen and Karen Carr have illustrated this animal but only as accompaniment to the Field Museum’s mount. But thanks to Barylambda’s appearance in Rudolph Zallinger’s Mural the Age of Mammals, it made it into an obscure toy set by Lido sold in Nabisco cereal in the 50s. However, otherwise it’s been invisible in popular media. The lack of pop cultural representation of animals between the Cretaceous and Pleistocene has pretty much frozen out Barylambda. In terms of mammal media, BBC’s Walking With Beasts was a godsend, but it ignored North America completely and so Barylambda missed its chance.

So anyway, Hollywood, give it a break. Museums, keep it on display. Toy companies, here’s a new fresh face. Authors, think about the crap you’re writing and how this genus could perk up the place. And remember, shop Barylambda where you work or play!