Few snakes are as overlooked as small fossorial species with little irregularity in color. Such is the case for neotropical earth snakes in the genera Geophis. Some species do in fact sport rings and brilliant colors like G. brachycephalus and its firey posterior body or the flashy yellow G. sartorii. However, many others are entirely uniform, as is the subject of this post. While walking past a leafcutter mound I’ve known for over 5 years, I saw its sleek black scales lying in the shadows of a small entrance hole. Ants were coming in and out, but the snake remained motionless. Out of curiosity for whether the snake was even alive, I extracted it from the hole, and upon close inspection I was struck by its enlarged prefrontal and parietal scales— large, dark, and sleek— a perfect suit of armor for headfirst burrowing.

Since leafcutter ants are such fervent defenders of their colony, it’s possible that Geophis has acquired adaptations to prevent its banishment by the ants. In many organisms that exploit ant colonies, a common strategy is to mimic the cuticular hydrocarbon profile of the ant’s exoskeleton, a type of chemical camouflage. A couple of examples include kleptoparasitic spiders that rob food sources from army ants, and rove beetles that similarly take advantage of black ants of the genus Lasius. The world of myrmecophiles (species that associate with ants) is rich with behavioral and morphological innovation, and I’d like to speculate the possibility of chemical ant trickery here in Geophis. Whether the snakes lay eggs in the homes of leafcutter ants, rob them of prey near the entrances, or simply use them as refuges, much remains to be discovered for the genus.

Photographed after disturbance [4]

Seromucous glands in Geophis zeledoni: 1) sl/supralabial in red, 2) il/infralabial in blue; illustration by Zaher et al. (2014). As a predator of earthworms, Geophis possess these glands that aid in the handling of highly viscous prey items. The infralabial glands have evolved twice in dipsadine snakes and also in other ecologically similar herpetofauna such as caecilians.. and likely amphisbaenians.
The semi-fossorial red coffee snake (Ninia sebae), another hunter of earthworms.. and a coral snake mimic! I spotted this individual with its tail end sticking out of a hollowed out log, two meters off the ground.

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