Let’s look at armadillos some more. Or, let’s look at more armadillos. I mean, let’s look more at armadillos. Whatever: armadillos! More.
Caption: a Pichi montage, showing wild individuals in (left) Torres del Paine National Park, southern Chile and (right) Chubut Province, Argentina. Note the overall covering of dark hairs and the long and gently curved claws on the forelimbs. The snout on the individual at left looks unusually short, I think because of foreshortening. Images: Wouter Potters, CC BY-SA 4.0 (original here); Mikelzubi, CC BY 3.0 (original here).
A relatively obscure yet apparently quite abundant armadillo, the Pichi, Dwarf armadillo or Pygmy armadillo is the sole species recognised within the genus Zaedyus, Z. pichiy. It’s native to southern Argentina and adjacent parts of eastern Chile where it’s associated with arid grassland. The southern part of its range – it occurs in areas bordering the Strait of Magellan – can be close to freezing in the (austral) winter, and a famous aspect of its biology is that it undergoes hibernation during times of environmental stress, it being the only extant xenarthran known to do this. Even when not hibernating, individuals can enter “prolonged torpor bouts lasting more than 24 hours” (Superina & Jahn 2013, p. 280), sometimes repeatedly.
Pichis can be easily distinguished from armadillos of other species thanks to their marginal scutes, which have triangular, pointed apices, this giving the carapace serrated borders. A pale longitudinal stripe along the dorsal midline is also supposedly diagnostic (Superina & Abba 2014), though I’m confused as I don’t see it in the photos here. The species is, however, similar enough to Euphractus (the six-banded armadillos) that some authors have considered the Pichi part of this genus, though this is not considered correct today.
Caption: museum taxiderm specimen of a Pichi at Museo Civico di Storia Naturale Giacomo Doria in Genoa, Italy. Image: Daderot, public domain (original here).
A niche debate on armadillo taxonomy. Current phylogeny and taxonomy has it that the Pichi is part of a clade that includes not just Euphractus but naked-tailed armadillos (Cabassous), three-banded armadillos (Tolypeutes) and others. Until recently, the convention was to include all extant armadillos within the family Dasypodidae. However, a deep split between the two main armadillo lineages – it appears to have occurred around 42 million years ago, within the mid Eocene (Gibb et al. 2016) – has led to the idea that long-nosed armadillos should be separated at the ‘family’ level from the others. Those ‘others’ are substantially more diverse, since euphractine armadillos, fairy armadillos, and tolypeutine armadillos (giant, three-banded and naked-tailed armadillos) all belong here (Gibb et al. 2016). The Pichi is a euphractine.
If we opt to recognise this split taxonomically*, the correct name for the long-nosed armadillo lineage is obviously Dasypodidae. The apparently most correct name for the other armadillo clade is Chlamyphoridae, based on a name published by Charles Lucien Bonaparte in 1850 for Chlamyphorus, the Pink fairy armadillo. Gibb et al. (2016) wrote that Bonaparte used the name ‘Chlamyphorinae’ but he actually published ‘Chlamydophorina’ based on his understanding that Chlamyphorus should be written Chlamydophorus (McKenna & Bell 1997, p. 82), a view established in 1830 by German zoologist Johann Georg Wagler. Chlamyphorus had been published just five years prior by physician and naturalist Richard Harlan and was intended to mean ‘cloak carrier’. However, because the Greek root of the ‘chlamys-’, ‘cloak’ part of the word is actually ‘chlamyd-’, Wagler thought that Harlan’s 1825 Chlamyphorus should really be written Chlamydophorus, hence Bonaparte’s Chlamydophorina.
* Remember: phylogeny and taxonomy are not the same thing. However, there has always been a general preference to get taxonomy to match phylogeny.
Caption: the two extant fairy armadillos are currently placed in separate genera. This is the Pink fairy armadillo Chlamyphorus truncatus, the smallest living armadillo. Good photos are hard to get; this is a taxiderm specimen at the Naturmuseum Senckenberg, Germany. Image: Daderot, public domain (original here).
What to do? Shouldn’t we be following the ‘incorrect’, now out-of-favour formulation of the name Chlamyphorus (namely Chlamydophorus) in devising higher names, since that’s what Bonaparte did? Well, no. Article 35.4 of the ICZN basically says that family-level names shouldn’t be based on spellings of genus names now considered ‘incorrect’. One more thing on this: given that Bonaparte used ‘Chlamydophorina’ based on ‘Chlamydophorus’, should he really be credited with Chlamyphoridae, as he is in Gibb et al. (2016)? Views differ on this and a popular convention is to wave this away by saying that we’re going with (in this case) Bonaparte’s concept of the name, even though the formulation isn’t right according to modern use, and even though the ‘rank’ we’re now assigning the name isn’t the same as that originally preferred.
One of the funnest findings of molecular phylogenetics on armadillos is that glyptodonts are part of Chlamyphoridae (Delsuc et al. 2016, Mitchell et al. 2016): they’re deeply nested within armadillos, not an armadillo sister-group as we used to think. So, yes – it is now properly correct to refer to glyptodonts as ‘giant armadillos’ (whereas this wasn’t considered technically correct beforehand). I’ll come back to that issue in time, since oh boy do I intend to revisit glyptodonts, a group I haven’t really written about since 2008.
Caption: cingulate (armadillo) phylogeny as recovered by Delsuc et al. (2016) on the basis of mitochondrial DNA extracted from a carapace fragment of the giant Pleistocene-Holocene glyptodont Doedicurus. Glyptodonts are nested within armadillos, and within chlamyphorids. This result has been obtained in more than one study and is now backed by anatomical data too. Image: Delsuc et al. (2016).
But back to the Pichi… I have to mention that the Pichi’s generic name Zaedyus – published by famed Argentine naturalist and palaeontologist Florentino Ameghino in 1889 – apparently means ‘very pleasant armadillo’ (Superina & Abba 2014).
Despite sometimes being called a ‘pygmy armadillo’, the Pichi isn’t that pygmy, head and body length reaching 35 cm (though between 22 and 31 cm is more typical) with an additional 13 cm or so for tail. It’s omnivorous, its diet including fungi, plants including mesquite pods, arthropods and small vertebrates of numerous sorts, and also carrion. If you recall the 2020 article from these here parts on armadillo carnivory and carrionophagy (err, yeah, let’s go with that), you might recall that the Pichi is one of several armadillos classified as an ‘omnivore-carnivore’ (Redford 1985), the species within the group being hard to group tidily in ordinarily dietary categories. It’s one of several mammals of arid habitats said not to drink water (Superina & Abba 2014).
Caption: another wild Pichi, specifically in Valdes Peninsula (a chunk of land that juts out into the Atlantic), north-east Chubut Province, Argentina. Valdes Peninsula is a nature reserve famous for the marine mammals that visit its shores. Image: Marianocecowski, CC BY-SA 3.0 (original here).
And that’s where we must end for now, with many thoughts on armadillos yet to be published.
For previous Tet Zoo articles on armadillos and othr xenarthrans, see…
Five things you didn’t know about armadillos, June 2007
What was that skull? (on glyptodonts), May 2008
I, Priodontes, the tatuasu, September 2008
Predation and Corpse-Eating in Armadillos, September 2010
The Fate of the Woolly Long-Nosed Armadillo of Peru, April 2024
Refs - -
Delsuc, F., Gibb, G. C., Kuch, M., Billet, G., Hautier, L., Southon, J., Rouillard, J.-M., Fernicola, J. C., Vizcaíno, S. F., MacPhee, R. D. E. & Poinar, H. N. 2016. The phylogenetic affinities of the extinct glyptodonts. Current Biology 26, R155-R156.
McKenna, M. C. & Bell, S. K. 1997. Classification of Mammals: Above the Species Level. Columbia University Press, New York.
Mitchell, K. J., Scanferla, A., Soibelzon, E., Bonini, R., Ochoa, J. & Cooper, A. 2016. Ancient DNA from the extinct South American giant glyptodont Doedicurus sp. (Xenarthra: Glyptodontidae) reveals that glyptodonts evolved from Eocene armadillos. Molecular Ecology 25, 3499-3508.
Redford, K. H. 1985. Food habits of armadillos (Xenarthra: Dasypodidae). In Montgomery, G. G. (ed) The Evolution and Ecology of Armadillos, Sloths, and Vermilinguas. Smithsonian Institution, Washington, D.C., pp. 429-437.
Superina, M. & Abba, A.M. 2014. Zaedyus pichiy (Cingulata: Dasypodidae). Mammalian Species 46, 1-10.
Superina, M. & Jahn, G. 2013. Effect of low-quality diet on torpor frequency and depth in the pichi Zaedyus pichiy (Xenarthra, Dasypodidae), a South American armadillo. Journal of Thermal Biology 38, 280-285.
