Smilodon Research Articles

A genomic exploration of the early evolution of extant cats and their sabre-toothed relatives.

BackgroundThe evolutionary relationships of Felidae during their Early–Middle Miocene radiation is contentious. Although the early common ancestors have been subsumed under the grade-group Pseudaelurus, this group is thought to be paraphyletic, including the early ancestors of both modern cats and extinct sabretooths.MethodsHere, we sequenced a draft nuclear genome of Smilodon populator, dated to 13,182 ± 90 cal BP, making this the oldest palaeogenome from South America to date, a region known to be problematic for ancient DNA preservation. We analysed this genome, together with genomes from other extinct and extant cats to investigate their phylogenetic relationships.ResultsWe confirm a deep divergence (~20.65 Ma) within sabretoothed cats. Through the analysis of both simulated and empirical data, we show a lack of gene flow between Smilodon and contemporary Felidae.ConclusionsGiven that some species traditionally assigned to Pseudaelurus originated in the Early Miocene ~20 Ma, this indicates that some species of Pseudaelurus may be younger than the lineages they purportedly gave rise to, further supporting the hypothesis that Pseudaelurus was paraphyletic.

Isotopic palaeoecology (δ 13C) of three faunivores from Late Pleistocene of the Brazilian intertropical region

ABSTRACT The palaeoecology of megamammals has been commonly accessed by stable isotope. Particularly in the Americas, this approach has been focusing efforts on the study of intertropical species, especially from a key paleozoogeographical region in the Late Quaternary of South America: the Brazilian Intertropical Region (BIR). Here we present an isotopic study (δ 13C) conducted on bioapatite samples of Smilodon populator, Protocyon troglodytes and Arctotherium wingei from the BIR. We discuss their potential prey preferences, niche width and overlap, and paleoenvironmental reconstitutions. Our results suggest a generalist carnivorous diet for P. troglodytes (δ 13C = – 5.0 ‰; BA = 0.83), a specialist C3 herbivorous diet and opportunistic scavenger behaviour for A. wingei (δ 13C = – 11.0 ± 2.1 ‰; BA = 0.00), and a specialist carnivorous diet for S. populator (δ 13C = – 8.5 ± 1.6 ‰; BA = 0.06). Within the Late Pleistocene of the BIR, P. troglodytes possibly inhabited open savanna-like environments, while S. populator and A. wingei occupied arboreal savanna forests. An atypical preference for small and medium-size prey for the predator S. populator, and a mainly herbivorous diet with a slight amount of meat for the bear A. wingei is also discussed.

Smilodon fatalis Bite Mechanisms: New Functional Considerations in Jaw and Articular Disk Reconstruction

Smilodon fatalis is among the most iconic of fossil sabertooths, best known for elongated canine teeth that enabled it to kill large prey. S. fatalis reconstructions published over the last 150 years (as well as many natural history exhibits) are typically modeled after living large conical tooth cat anatomy because there are no living sabertooths. Dental and correlated musculoskeletal differences between the living and extinct cats with the two different dentition types have led to misinterpretations of the appearance and gape capabilities of Smilodon. Historically, the way in which the S. fatalis skull and mandible soft tissues have been reconstructed does not take into account the bite angles that are the most useful for a living cat. Specifically, the angle at which the mandible and maxilla can move in relation to one another must also account for the effect generated by the muscles and tendons that limit jaw opening and closing. The usual reconstructed display shows a mandible that could not open sufficiently to allow a gape wide enough to encompass the diameter of a chicken's egg. The jaw joint is often oriented so that it would not generate much bite force, as it sometimes is positioned to look as though it is dangling uselessly. The articular disk has been ignored. In this study, we are testing hypotheses related to the typically depicted canine tooth positions and the lack of inclusion of soft tissue influences such as the articular disk that is usually present in the craniomandibular joint. By reconstructing the size, shape, thickness, and then inserting an articular disk, the jaw then lines up correctly, and a bite force can be more accurately calculated. We tried several different methods of estimating the size of the articular disk using paper, leather, felt, and silicone until we found one that allowed the mandible and maxilla to line up precisely. This works to solve the two common issues; computer-based studies that modeled the amount of bite force in S. fatalis with a few showing a powerful bite and secondly, canines are often mounted so far out of their alveoli that the S-shaped dentine margin is exposed. Exposed dentine and jaw misalignment would be very painful to a living animal and would decrease the mechanical advantage of the upper canines. When the upper canine alveoli are not maximally filled, the teeth are less securely anchored. By seating the upper canines properly S. fatalis could use these teeth with a decreased likelihood of breakage from the bite forces generated. S. fatalis evolved with long slender bladelike canines. This tooth configuration would be especially susceptible to breakage from large bending moments and torque. To use these teeth effectively, the bite needs to be in line with the anteroposterior axis of the head and aimed toward the jugular groove of the neck of prey, with minimal side-to-side movement. Anchoring the canines securely in their alveoli helps eliminate this problem. Our data shows that revisioning the S. fatalism skull gives a more accurate picture of the way this cat lived, killed its large prey, and our new data allows for scientists recalculate bite forces.

Dietary ecology of the scimitar-toothed cat Homotherium serum

The scimitar-toothed cat Homotherium was one of the most cosmopolitan cats of the Pleistocene, present throughout Eurasia, Africa, and the Americas until at least ~28 thousand years ago.1-3 Friesenhahn Cave (Bexar County, Texas) contains some of the best-preserved specimens of Homotherium serum alongside an abundance of juvenile mammoths, leading some to argue that H.serum preferentially hunted juvenile mammoths.1,4 Dietary data of Homotherium are rare, with their ecology inferred from morphological, taphonomic, and genetic data.1,3-10 Here, we use a multi-proxy approach to clarify the dietary ecology of H.serum as compared to extinct and extant cats and their relatives. Dental microwear texture analysis (DMTA) reveals that H.serum consumed soft and tough foods, similar to the extant cheetah, which actively avoids bone,11,12 but in stark contrast to extant lions and hyenas, which are observed to engage in durophagy (i.e., bone processing).11-14 DMTA data are consistent with taphonomic evidence of bone defleshing and the absence of bone-crunching behavior in H.serum. Stable carbon isotope values of H.serum indicate a clear preference for C4 grazers including juvenile mammoths, in agreement with taphonomic evidence suggestive of a "Homotherium den"1,4 and morphological data indicative of a relatively cursorial lifestyle.6-8 Notably, the inferred diet of H.serum contrasts with the extinct dirk-tooth sabertooth cat Smilodon fatalis, which preferred forest/woodland prey and engaged in bone processing.15-19Homotherium serum exhibited a novel combination of morphological adaptations for acquiring open-country prey, consuming their soft and tough flesh-including the tough flesh of juvenile mammoths. VIDEO ABSTRACT.

A genomic exploration of the early evolution of extant cats and their sabre-toothed relatives

Background: The evolutionary relationships of Felidae during their Early–Middle Miocene radiation is contentious. Although the early common ancestors have been subsumed under the grade-group Pseudaelurus, this group is thought to be paraphyletic, including the early ancestors of both modern cats and extinct sabretooths. Methods: Here, we sequenced a draft nuclear genome of Smilodon populator, dated to 13,182 ± 90 cal BP, making this the oldest palaeogenome from South America to date, a region known to be problematic for ancient DNA preservation. We analysed this genome, together with genomes from other extinct and extant cats to investigate their phylogenetic relationships. Results: We confirm a deep divergence (~20.65 Ma) within sabre-toothed cats. Through the analysis of both simulated and empirical data, we show a lack of gene flow between Smilodon and contemporary Felidae. Conclusions: Given that some species traditionally assigned to Pseudaelurus originated in the Early Miocene ~20 Ma, this indicates that some species of Pseudaelurus may be younger than the lineages they purportedly gave rise to, further supporting the hypothesis that Pseudaelurus was paraphyletic.

Smilodon fatalis siblings reveal life history in a saber-toothed cat.

SummaryThe saber-toothed cat Smilodon fatalis is known predominantly from “predator trap” deposits, which has made many aspects of its life history difficult to infer. Here, we describe an association of at least two subadult and one adult S. fatalis from Pleistocene coastal deposits in Ecuador. The assemblage likely derived from a catastrophic mass mortality event, and thereby provides insights into the behavior of the species. The presence of a P3 in the subadult dentaries suggests inheritance, a rare instance of familial relatedness in the fossil record. The siblings were at least two years old and were associated with an adult that was likely their mother, indicating prolonged parental care in S. fatalis. Comparison with the growth of pantherine cats suggests that S. fatalis had a unique growth strategy among big cats that combines a growth rate that is similar to a tiger and the extended growth period of a lion.

An eye for a tooth: Thylacosmilus was not a marsupial "saber-tooth predator".

BackgroundSaber-toothed mammals, now all extinct, were cats or “cat-like” forms with enlarged, blade-like upper canines, proposed as specialists in taking large prey. During the last 66 Ma, the saber-tooth ecomorph has evolved convergently at least in five different mammalian lineages across both marsupials and placentals. Indeed, Thylacosmilus atrox, the so-called “marsupial saber-tooth,” is often considered as a classic example of convergence with placental saber-tooth cats such as Smilodon fatalis. However, despite its superficial similarity to saber-toothed placentals, T. atrox lacks many of the critical anatomical features related to their inferred predatory behavior—that of employing their enlarged canines in a killing head strike.MethodsHere we follow a multi-proxy approach using canonical correspondence analysis of discrete traits, biomechanical models of skull function using Finite Element Analysis, and 3D dental microwear texture analysis of upper and lower postcanine teeth, to investigate the degree of evolutionary convergence between T. atrox and placental saber-tooths, including S. fatalis.ResultsCorrespondence analysis shows that the craniodental features of T. atrox are divergent from those of placental saber-tooths. Biomechanical analyses indicate a superior ability of T. atrox to placental saber-tooths in pulling back with the canines, with the unique lateral ridge of the canines adding strength to this function. The dental microwear of T. atrox indicates a soft diet, resembling that of the meat-specializing cheetah, but its blunted gross dental wear is not indicative of shearing meat.ConclusionsOur results indicate that despite its impressive canines, the “marsupial saber-tooth” was not the ecological analogue of placental saber-tooths, and likely did not use its canines to dispatch its prey. This oft-cited example of convergence requires reconsideration, and T. atrox may have had a unique type of ecology among mammals.

A Study of the Sinuous Crouch of Smilodon fatalis

Mammalian carnivores generally are considered to belong either to the pursuit or ambush predator categories. Anatomical features for these opposing styles of capturing prey differ, although specific strategies typify familial taxonomic levels. The species of the Canidae tend toward pursuit, while most of the Felidae specialize in ambush. Cats also engage in prey stalking behavior, whether an ambush or pursuit predator. Remaining cryptic for as long as possible is a good strategy to increase the success of a hunt, especially when the quarry sought is fleet of foot, agile, wary and highly capable of evading predation. The extinct sabertooth cat, Smilodon fatalis, has long been considered to be an ambush predator because it was large‐bodied and short‐limbed. Smilodon’s skeleton is robust, and has been reconstructed as heavily muscled because it shows prominent muscle scars. Because of this high degree of robustness, it has also been thought to have had questionable flexibility. No characters showing specific enhancements to Smilodon’s adaptations for clandestine stalking despite its formidable musculoskeletal anatomy have been identified in a search of the published literature. This study describes morphological features that have been newly identified as being able to improve this sabercat’s ability to move sinuously and stealthily during an ambush. These are derived from unique pectoral girdle and forelimb, vertebral column and pelvic girdle and hindlimb features. Specifically, truncated scapular and ilial shapes as well as short limbs give Smilodon a lower crouching profile than can be achieved by other felids. Usually, in sinuously moving cats, even when the animal is seeking to remain as cryptic as possible, the posterodorsal aspect of the scapula and the anterodorsal ilial regions project above the pointed dorsal tips of the elongated vertebral spinous processes. These highest projections may be visible above any vegetation cover, revealing the cat’s presence to potential prey. In contrast, in Smilodon, with fore and hindlimbs equivalently flexed, the shoulder and hip regions fall below the level of the most dorsal tips of the spinous processes, enhancing the cat’s ability to flatten its body to facilitate concealment while stalking. This study interprets the unique morphological limb features in Smilodon as adaptations to enhance the sinuous movements the cat used in getting as close to potential prey animals as possible prior to making a final rush to grapple with them. We also demonstrate how this anatomy leads to the conclusion that Smilodon’s habits fit it to its forested or scrub environment as a solitary ambush predator.

Pleistocene mammals from Extinction Cave, Belize

A small mammalian fauna is recorded from Extinction Cave (also called Sibun Cave), east of Belmopan, on the Sibun River, Belize, Central America. The animals recognized are armadillo (†Dasypus bellus), American lion (†Panthera atrox), jaguar (Panthera onca), puma or mountain lion (Puma concolor), Florida spectacled bear (†Tremarctos floridanus), javelina or collared peccary (Pecari tajacu), llama (Camelidae indet., †?Palaeolama mirifica), red brocket deer (Mazama americana), bison (Bison sp.) and Mexican half-ass (†Equus conversidens); sabre-toothed cat (†Smilodon fatalis) may also be represented. “†” indicates an extinct taxon. Bear and bison are absent from the region today. The bison record is one of the more southerly known. The bear record is almost the most westerly known and a first for Central America.

Occurrence of the sabretooth cat Smilodon populator (Felidae, Machairodontinae) in the Cuvieri cave, eastern Brazil

Occurrence of the sabretooth cat Smilodon populator (Felidae, Machairodontinae) in the Cuvieri cave, eastern Brazil

Taxonomy and paleoenvironmental inferences from fossil vertebrates of Paripiranga Borboletas Cave, Northeastern Bahia, Brazil

The fossil mammals that lived in the Brazilian Intertropical Region during the Quaternary are found in different types of deposits (e.g. natural tanks, ponds, caves, rockshelter, and riverbeds) throughout the Brazilian territory. The state of Bahia, located on northeastern Brazil, stands out for the presence of large and important caves, which are characterized by the natural deposition of sediments and fossils. The study aims to identify the fauna found in the Borboletas Cave, and to provide the first paleoecological inferences for the environment during the Late Pleistocene-Holocene. Here we present the first record of Palaeolama major, Hippidion principale and Smilodon populator in Paripiranga, Bahia. Coendou sp., Mazama gouazoubira, and Toxodon platensis, already known to the region, were also collected and identified. Based on the chronological and geographical distribution of the taxa, it is suggested that the faunal content found lived during the Late Pleistocene – Holocene. The presence of the taxa found indicate an open paleoenvironment, similar to savanna, with areas covered with grasses associated with areas with forest cover. This study demonstrates that the Borboletas Cave is the richest paleontological site carrying the mammals in this region.

Pleistocene paleoecology and feeding behavior of terrestrial vertebrates recorded in a pre-LGM asphaltic deposit at Rancho La Brea, California

Sixteen taxa comprising extinct megafauna and extant species from a single asphalt deposit (Project 23, Deposit 1) at Rancho La Brea were isotopically analyzed (δ13C, δ15N, δ34S) and 14C dated to investigate paleoecology and feeding behavior of terrestrial vertebrates in southern California during the late Pleistocene. The large majority of the 14C dates cluster between ~35 and 36 kyr BP, but a range of ages indicate this seep was active from ~30 to >43 kyr BP. Many of the Smilodon fatalis and Canis dirus as well as the Canis latrans have similar δ13C (~–19‰ to −18‰) and δ15N (~11‰ to 12‰) results, indicating that these predators may have consumed similar prey species and possibly competed with each other through hunting and/or scavenging. The remains of contemporary potential prey species for these three predators include juvenile Bison antiquus and Camelops hesternus, and possibly adult Paramylodon harlani and Capromeryx minor. However, the δ15N results of a single C. dirus (8.9‰) and the Panthera atrox (8.3‰) were significantly lower than the other large predators. Potential prey for this dire wolf and lion include Nothrotheriops shastensis, Equus occidentalis and possibly Mammut americanum. Many of the herbivores appear to have utilized broadly similar C3 ecological environments. However, the adult E. occidentalis had isotopic results similar to the Sylvilagus sp. and Spermophilus beecheyi that have restricted home ranges, suggesting this horse was similarly local in its distribution or consumed a similar plant food selection. The isotopic values for extant taxa (Actinemys marmorata, Crotalus sp., Mustela frenata) suggest similar dietary patterns to their modern counterparts, indicating their ecological niches have remained relatively constant. The results presented here establish a foundation for future diachronic studies to better understand how the climate of the last ~50 kyr BP impacted biodiversity and ecological communities in southern California.

Late Pleistocene records of felids from Medicine Hat, Alberta, including the first Canadian record of the sabre-toothed cat Smilodon fatalis

In the late 1960s, a team led by C.S. Churcher and A. MacS. Stalker collected over 1000 vertebrate fossils, mostly representing large herbivorous mammals, from bluffs along the South Saskatchewan River near Medicine Hat, Alberta, Canada. The records from this area also include the only documented case of the sabre-toothed cat Smilodon fatalis, but these specimens have not been described or illustrated, and therefore, their identification has never been verified. Here, all felid fossils recovered from the Medicine Hat bluffs are described and identified. We confirm the presence of the machairodontine S. fatalis and three additional taxa: the feline Lynx and the pantherines Panthera cf. P. atrox (American lion) and Panthera cf. P. spelaea (cave lion). Notably, this record of S. fatalis is its first confirmed occurrence in Canada and is a significant northerly range expansion, bringing the global distribution of this species in line with what is typical for a large felid. Should the tentative record of Panthera cf. P. spelaea be correct, this would represent its first occurrence in Alberta and a southeastern range extension, bringing it into the range of P. atrox. The possible presence of both P. atrox and P. spelaea suggests that Late Pleistocene pantherine biogeography in North America may be more complex than previously believed, particularly during relatively warm interglacial periods.

Locomotor correlates of the scapholunar of living and extinct carnivorans.

The relationship of carpal morphology to ecology and habitat is under studied in carnivorans and more generally in mammals. Here, we use 3D-scanning techniques to assess the usefulness of a carpal bone, the scapholunar, in carnivorans to reflect ecology and habitat, and to reconstruct the ecology of five extinct carnivorans from two fossil sites: Rancho La Brea and Natural Trap Cave. We 3D-scanned scapholunars and measured articular surface areas and angles between articular facets using GeoMagic and Rhino 3D-software. We analyzed the difference in these metrics using multivariate analysis of variance and discriminant function analysis. Results show that the scapholunar reflects ecological signal, with clear groupings of cursorial carnivorans and grappling/climbing carnivorans; however, phylogenetic signal was also present in the results with hyaenids, canids, and large felids in distinct morphospaces. Extinct species Miracinonyx trumani (American cheetah) and Smilodon fatalis (sabertooth cat) showed surprising results with M. trumani grouping with pantherines instead of Acinonyx or Puma, suggesting it runs but still retains the ability to grapple prey. S. fatalis groups with pantherines, but also shows some unique adaptations, suggesting it had a different range of wrist motion than living cats. Overall, the scapholunar is a good indicator of ecology and functional morphology and can be another tool to use in modern and fossil carnivorans to reconstruct extinct ecologies and locomotor behaviors.

Static Scaling and the Evolution of Extreme Canine Size in a Saber-Toothed Cat (Smilodon fatalis).

The canines of saber-toothed cats are a classic example of an extreme morphology, yet important questions pertaining to their evolution remain unanswered. Recent analyses suggest these structures functioned as tools of intrasexual combat where trait size acts as both a weapon of battle and signal of competitive ability. However, classic skeletal reconstructions suggest saber-tooth canines evolved as specialized hunting tools. Either scenario could have led to the evolution of extreme canine size and distinguishing between these hypotheses is therefore difficult. This is made more challenging by the fact that natural observation of saber-toothed cats is impossible, and biologists must rely on measures of static morphology to study the patterns of selection that favored extreme canine size. Here I analyze the static intraspecific scaling relationship between canine size and body size in the saber-toothed cat, Smilodon fatalis, to determine whether or not extreme canine size functioned as a sexually selected signal. I review the literature surrounding the evolution of sexually selected signals and the methods recently established by O'Brien etal. (2018), show how static scaling relationships can be useful, reliable tools for inferring patterns of selection, especially in fossil organisms, and provide evidence that extreme canine size in saber-toothed cats was not the product of selection for effective sexual signals, but instead evolved as either a pure intrasexually selected weapon or a hunting tool.

Evidence of intraspecific agonistic interactions in Smilodon populator (Carnivora, Felidae)

The saber-toothed cat Smilodon is a characteristic genus of the Pleistocene faunas of the American continent. Smilodon belongs to an extinct clade of felids that had hypertrophied blade-like upper canines. Because the length of the canines is so extreme, the killing bite of Smilodon is a hotly debated topic in vertebrate paleontology. Some authors have proposed that saber-toothed cats had a weak bite and their canines were fragile, not useful for attacking prey or penetrating bones. The aim of the present contribution is to describe two new specimens of Smilodon populator that have injuries on their skulls. Although it cannot be ruled out that the injuries were caused by a potential prey kicking the skull, the size, shape and general features of the injuries suggest that they were inflicted by the upper canines of another Smilodon individual during agonistic interactions.

Panthera balamoides and other Pleistocene felids from the submerged caves of Tulum, Quintana Roo, Mexico

ABSTRACT Here we describe a new species of a Pleistocene felid based on the distal third of a right humerus from the submerged El Pit cenote (sinkhole) near Tulum in Quintana Roo, Mexico. The new taxon, Panthera balamoides sp. nov., is characterized by a large entepicondylar foramen, a gracile and straight humeral shaft with a prominent supracondylar ridge with a small depression on the lateral epicondyle and a distal articular surface located medially with respect to the long axis of the shaft. Two felid clavicles from the same locality have been assigned to Panthera atrox, while a humerus fragment from the Kim Ha cave near Tulum likely corresponds to Smilodon gracilis. Panthera balamoides lines up with other likely endemic mammals in the region, which suggest that at least northern Quintana Roo, if not the entire Yucatán peninsula, may have been ecologically isolated during the Pleistocene, due to the repeated expansion of grassland.

Distinct Predatory Behaviors in Scimitar- and Dirk-Toothed Sabertooth Cats

Over the Cenozoic, large cat-like forms have convergently evolved into specialized killers of "megaherbivores"that relied on their large, and laterally compressed (saber-like) canines to rapidly subdue their prey [1-5]. Scimitar- and dirk-toothed sabertooths are distinct ecomorphs that differ in canine tooth length, degree of serration, and postcranial features indicative of dissimilar predatory behavior [6-13]. Despite these differences, it is assumed that they used a similar "canine-shear" bite to kill their prey [14, 15]. We investigated the killing behavior of the scimitar-toothed Homotherium serum and the dirk-toothed Smilodon fatalis using a comparative sample of living carnivores and a new quantitative approach to the analysis of skull function. For the first time, we quantified differences in the relative amount and distribution of cortical and trabecular bone in coronal sections of skulls to assess relative skull stiffness and flexibility [16-19]. We also use finite element analysis to simulate various killing scenarios that load skulls in ways that likely favor distinct proportions of cortical versus trabecular bone across the skull. Our data reveal that S.fatalis had an extremely thick skull and relatively little trabecular bone, consistent with a large investment in cranial strength for a stabbing canine-shear bite. However, H.serum had more trabecular bone and most likely deployed an unusual predatory behavior more similar to the clamp-and-hold technique of the lion than S.fatalis. These data broaden the killing repertoire of sabertooths and highlight the degree of ecological specialization among members of the large carnivore guild during the Late Pleistocene of North America.

Large Carnivore Footprints from the Late Pleistocene of Argentina

ABSTRACTThe aim of the present contribution is to describe large felipedid footprints from a new ichnological site from the Late Pleistocene of Buenos Aires Province, Argentina. The prints are referred as the new ichnospecies Felipeda miramarensis nov. ichnosp. Based on size and morphology, this new ichnotaxon may have been produced by the large machairodontine felid Smilodon populator. Track analysis indicates that the producer of the tracks had fully retractile claws, a plantigrade feet, and lacked strong supination capabilities on pes and manus. The size and depth differences between manus and pes prints indicate that the producer had notably robust anterior limbs. If correctly assigned, the new ichnospecies reinforces the idea that Smilodon was an ambush predatory mammal.

Olfaction written in bone: cribriform plate size parallels olfactory receptor gene repertoires in Mammalia.

The evolution of mammalian olfaction is manifested in a remarkable diversity of gene repertoires, neuroanatomy and skull morphology across living species. Olfactory receptor genes (ORGs), which initiate the conversion of odorant molecules into odour perceptions and help an animal resolve the olfactory world, range in number from a mere handful to several thousand genes across species. Within the snout, each of these ORGs is exclusively expressed by a discrete population of olfactory sensory neurons (OSNs), suggesting that newly evolved ORGs may be coupled with new OSN populations in the nasal epithelium. Because OSN axon bundles leave high-fidelity perforations (foramina) in the bone as they traverse the cribriform plate (CP) to reach the brain, we predicted that taxa with larger ORG repertoires would have proportionately expanded footprints in the CP foramina. Previous work found a correlation between ORG number and absolute CP size that disappeared after accounting for body size. Using updated, digital measurement data from high-resolution CT scans and re-examining the relationship between CP and body size, we report a striking linear correlation between relative CP area and number of functional ORGs across species from all mammalian superorders. This correlation suggests strong developmental links in the olfactory pathway between genes, neurons and skull morphology. Furthermore, because ORG number is linked to olfactory discriminatory function, this correlation supports relative CP size as a viable metric for inferring olfactory capacity across modern and extinct species. By quantifying CP area from a fossil sabertooth cat (Smilodon fatalis), we predicted a likely ORG repertoire for this extinct felid.