We left southwards through the first two, Colima and Michoacán, without incident on our way towards the first stop in the Sierra Madre del Sur in Guerrero. These rugged and largely untamed mountains are widely known as one of the country's opium production hotspots — where the poppy culture is a generations-old part of normal life.
When we first ventured down the five-hour trail into these hills nearly a decade ago, the people we encountered were friendly. While most played some role cultivating, defending, and/or trafficking — people generally appeared happy and the poppies were just another cash crop. Subsequent years transformed those mountains as Mexico's war on drugs left criminal organizations destabilized. Local groups took up arms as power vacuums opened in a flurry of murders and occasional arrests.
The HERP.MX Field Team took a hiatus after being tipped-off to one local leader's plan to kidnap us for ransom. Some years later he was ambushed and murdered, allowing us to resume our survey efforts — but these were hardly the same mountains. Our friends were ready for war — their machettes and hand-stiched satchels replaced by kalashnikovs and bullet-proof vests. The instructions were different: no more wandering the hills. The town down the road had raided this one and killed someone, sometime, for some reason — and in blood-for-blood fashion they'd been exchanging carnage for years.
So for this trip in January, we knew the drill. We call a number that rings a satellite phone deep in the mountains. The woman who answers relays our message via radio to a contact some kilometers away. That contact then runs the message up the hill to our friend who sends word to his brother leading the local convoy of hitmen.
"¡Los biólogos llegarán el sábado!"
With that, and some stops to remind the halcones (a slang term for "lookouts") of our non-threatening nature, we've secured passage to the land of the Guerreran Long-Tailed Rattlesnake.
We hit the hills which, despite their lush appearance, were beginning to sound like the extra crunchy dry season. Not suprisingly, the herpetofauna was few and far between, but what we lacked in quantity we recovered in quality.
This juvenile female Guerreran Long-Tailed Rattlesnake set the morning off on the right note, but it would be the only one of the trip.
The Guerreran Long-tailed Rattlesnake was discovered in 2008 by a field team from UTA and UNAM led by Eric Smith — who, to the bemusement of rattlesnake fans world-wide, notoriously fumbled the encounter when he suggested the snake might be a Crotalus molossus. Nonetheless, the specimen was described in 2008 by Jonathan Campbell and Oscar Flores and christened Crotalus ericsmithi.
In the years since the description, the HERP.MX Field Team has been fortunate to secure additional snakes, and the species is now known from a few dozen specimens from three sites in the Sierra Madre del Sur in Guerrero.
Even so, C. ericsmithi continues to be one of Mexico's rarest pitvipers, and virtually nothing is known of its habits or true distribution. Additional trips are planned for this season to hopefully shed some light on this rare rattlesnake.
Towards the end of 2017 we began assisting researchers in Mexico City with a project involving multiple new species of Gerrhonotus — among them is a primitive keeled-scaled form distributed along México's Pacific coast. Sampling from Guerrero suggested that the species was replaced by another alligator lizard, Gerrhonotus liocephalus, in the Guerreran Sierra Madre del Sur.
The fall and winter are generally considered prime-time for this group of Anguids as, unlike many other taxa in this region, it's the peak of breeding season. While you might see one or two Gerrhonotus in the tropical deciduous forests during the monsoon season, you can happen upon one or two dozen with simlar effort during the winter. Our second target of this trip was to hopefully catch the local species of alligator lizard, and confirm if G. liocephalus could be found in the area.
To our pleasant surprise, we were able to secure an adult male alligator lizard that WAS NOT G. liocephalus! Further analysis is underway to determine whether the lizard represents a signficant range extension for the new species already in the works, or an entirely new form.
Content with our results, we started our long drive out of the mountains. Once into the flatlands, we stopped for a bolillo relleno — a local dish featuring a small loaf of bread stuffed with slow-roasted pork, onions, potatoes, squash, carrots, and chiles — the ideal fuel for a long trip south to Oaxaca.
Crossing just half of Oaxaca took much longer than expected, and we didn't arrive at our target mountain range until the early morning hours. A quick break to stretch our legs in a river yielded a couple amphibian species before spending the night at the base of mountain we planned to ascend the following morning.
After a couple hours of sleep, we started up the mountain towards our third and final target: the Broad-Horned Pitviper (Ophryacus sphenophrys). Large swaths of the natural habitat here have been cleared for coffee production, and the snakes don't seem to mind as they're readily found basking within the plantations.
Just four years ago, the Broad-horned Pitviper (Ophryacus sphenophrys) was known from just three specimens, and held the title as North America's Rarest Viper (in terms of specimens known to science). Since publishing the redescription in 2015, the HERP.MX team has been fortunate to secure over a dozen additional specimens, bumping this species to 2nd place behind Crotalus tancitarensis.
Much like the Tancítaran Cross-Banded Rattlesnake (C. tancitarensis), O. sphenophrys is only known from a single mountain. Despite multiple attempts to locate this species in suitable habitat on adjacent hills, we've only been able to turn-up the much more common Ophryacus undulatus. While we're hopeful that additional populations will be located, we're currently working to establish an assurance colony of these potentially micro-endemic and enigmatic vipers.