Aenocyon dirus (Leidy, 1858)

Davis, Matt, Nye, Benjamin D., Sinatra, Gale M., Swartout, William, Sjӧberg, Molly, Porter, Molly, Nelson, David, Kennedy, Alana A. U., Herrick, Imogen, Weeks, Danaan DeNeve & Lindsey, Emily, 2022, Designing scientifically-grounded paleoart for augmented reality at La Brea Tar Pits, Palaeontologia Electronica (a 9) 25 (1), pp. 1-37 : 15-17

Aenocyon dirus

( Figure 9 )

Appearance. Our reconstruction of the extinct dire wolf was developed before recent genetic analyses shattered the long held belief that dire wolves and extant grey wolves ( Canis lupus ) were closely related (Perri et al., 2021). Perri et al. (2021) found that dire wolves likely belonged to an isolated New World lineage that split from living canids about 5.7 million years ago and should thus be placed in the monotypic genus Aenocyon . It is unclear how this evidence should alter the traditional reconstruction of dire wolves as slightly larger and stockier grey wolves; even this new study arguing for reclassification confirmed that dire and grey wolves were morphologically very similar in their skeletal anatomy. In publicity for their study (Grimm, 2021), but not their research paper itself, the authors of the genetic study (Perri et al., 2021) suggested that because dire wolves lived in warmer latitudes of North America, they may have had characteristics of animals in these areas like rounded ears, bushy tails, and red fur. Perri said they may have resembled, “a giant, reddish coyote” (Grimm, 2021).

DAVIS ET AL.: LA BREA TAR PITS PALEOART

Accordingly, a new reconstruction of dire wolves with reddish orange coats by paleoartist Maurico Antón accompanied press releases for the new study (Grimm, 2021). In a tweet (2021), Antón explained that for the coat color he, “mixed features from dholes (which I found to be even more variable than I assumed), Simien wolves, dingoes and even maned wolves for good measure!” While dire wolves could have certainly been reddish, we don’t find anything in Perri (2021) that specifically suggests this coloration is more probable than any other. The wide latitudinal range of dire wolves has long been known, and they were common near ice sheets in mammoth steppe habitats and the highaltitude Bolivian altiplano, as well as much warmer climes like Pleistocene Southern California, Venezuela, and coastal Peru ( Dundas, 1999). The reddish coats do work well to counteract perceptions that dire wolves resembled large versions of grey wolves though.

For his latest reddish orange dire wolf reconstruction (Grimm, 2021), Antón used an older musculoskeletal study he had originally developed for a book on canid evolution (Wang and Tedford, 2008) saying that, “dire wolf anatomy remains the same” (Antón, 2021). This is the same reconstruction we used for our model ( Figure 9 ), albeit with its original more wolf/coyote like coat. We think that reddish coats and more traditional wolf/coyote coats are both reasonable for dire wolves. Until we find new paleontological or genetic evidence, the coloration of dire wolves remains speculative.

Behavior. For animations, we followed the locomotion and behavior of extant grey wolves. The large number of dire wolf skeletons preserved in the Tar Pits suggests social, pack-like behavior (Carbone et al., 2009) so we showed them in small groups

PALAEO- ELECTRONICA.ORG when possible. As with bison, the group sizes we displayed virtually were smaller than they likely would have been in reality due to space constraints in the animated scenes. For vocalizations, we used a grey wolf pitched lower based on recent morphological analyses of preserved dire wolf hyoids that hypothesized they could have sounded like lower frequency grey wolves ( Flores et al., 2020).

American Lion

Figures

FIGURE 9. Low poly reconstruction of the extinct dire wolf (Aenocyon dirus). To view this model in 3D, please see the online version of this article.