FAM 62128, the Nambé felid skeleton:
From 1932 to 1965, Childs Frick sent numerous collecting parties into the fossiliferous terrestrial localities of Tertiary North America. The Frick Laboratory assembled a magnificent collection of fossil mammals as a result of these expeditions. Now referred to as the Frick Collection, this assemblage of fossil mammals is housed in the collections of the Division of Paleontology of the American Museum of Natural History. Within the Frick Collection is the world's most comprehensive fossil felid collection. Fossils of the first felids to arrive in North America, in the late Hemingfordian, were collected in localities of the Sheep Creek Formation of Nebraska and the Tesuque Formation of New Mexico. The earliest known partial felid skeleton (FAM 62128) was recovered from the Nambé Member of the Tesuque Formation of New Mexico and described by me in 2001. Photo by Chester Tarka of the AMNH.
By carefully identifying and measuring the anatomical structures present in this early felid skeleton, I was able to determine how closely it resembled other fossil cats and the cats who are alive today. Photo by Mick Ellison .upper third incisor (I3), upper canine (C), upper first premolar (P1), alveolus or socket for upper second premolar (P2 alv), petrosal (P), mastoid (M), paroccipital process (PP).
This is the left front paw of FAM 62128. Third phalanges (ph3) are the bones of the toes that include the cats' claws. The ph2 lateral concavity is referring to the place where this cat could retract his claws, just as today's cats do. Mc5, Mc2 are the fifth and second metacarpal bones. Photo by Mick Ellison
This is the articulated right rear paw of the New Mexico skeleton (FAM 62128) in dorsal (A) and ventral (B) views.(ses) = sesamoid bones, nav = navicular, cu = cuboid, ent = entocuneiform, lat conc = lateral concavity of second phalanx. Photo by Mick Ellison
diastema jaw: This is an illustration of the type specimen of Pseudaelurus marshi, a fossil lower jaw of a cat who lived in North America in the middle Miocene, approximately 13 million years ago. The illustration is featured in the original description of this fossil, written by the paleontologist Malcolm Rutherford Thorpe in 1922. I scanned this illustration and then added the reference to the distance from c-p3. Early on in my research on the early cats of North America, I realized that the space between the lower canine (c) and the third premolar (p3) was a character that could possibly differentiate species in both extinct and modern felid taxa.
The coronoid process (CP) or vertical ramus of the lower jaw of felids is another anatomical feature that is variable in fossil felids. A is Proailurus lemanensis, the earliest known felid, with a short, wide, and erect coronoid process. This cat lived approximately 23 million years ago. B and C are felids that are approximately 16 million years old. Their coronoid processes have become relatively taller, but are still erect. The felid labeled D has a tall coronoid process that is no longer erect. It slopes to the right, to the rear of the cat's skull. This cat lived in North America approximately 13 million years ago. E is a modern, extant, or living cat (Panthera leo, the lion). This coronoid process is tall, sloping, and has a terminal hook.
FAM 61835, the Echo Quarry felid skull: This is the basicranium, the left side of the base of the skull of a North American cat who lived approximately 16 million years ago. By comparing this part of the skull with other extinct carnivores and with cats that are alive today, I am able to hypothesize or speculate on the relationships of this cat. Photo by Tom Rothwellectotympanic (T), limit of the caudal entotympanic chamber (ce), paroccipital process (pp), anteromedial process of the auditory bulla (am), petrosal (P), paroccipital process (pp), entotympanic (E), hypoglossal foramen (hf).
This wonderful fossil (UNSM 25490) is a partial skull, the type specimen of Pseudaelurus stouti, a small cat who lived in North America approximately 14 million years ago. It is housed in the University of Nebraska State Museum. We are looking at the upper dentition. This cat was similar in size as our domestic cats of today. However, notice that this cat has four upper premolars. The cat in your house or barn would have P2, but no longer has P1. The modern, domestic cat has evolved without a first upper premolar (P1). It has lost this anatomical feature or character. Photo by Tom Rothwell
