Following the path of walking fishes in Thailand

A Mon Temple in Sangkhlaburi

            From January 21-31st PhD student Pam Hart, undergraduate Valencia Henderson, and I went to Thailand to study freshwater fishes along with the labs of Brooke Flammang (NJIT, Rutgers), Larry Page (University of Florida) and local Thai collaborators from multiple universities. This work is part of the goals of our National Science Foundation, Understanding Rules of Life Grant that was funded this year (2020). The goals of that grant include studying fishes in the family Balitoridae (Hillstream Loaches) with our LSU side providing genome-level analyses. The grant also includes robotics and biomechanics (led by Rutgers/NJIT) and CT scanning work (led by UF).

The mug of Garra fuliginosa

            I have been to Thailand before but was mostly in Bangkok and the island of Phuket targeting marine species. This time around we focused on tadpole-sized freshwater loaches that live under rocks in mostly shallow streams. This trip marked my 15^th to Asia but each time feels new, this was Valencia and Pam's first trip across the Pacific and there would be lots of new sites, smells and sounds for them. Along with the balitorids we got other fishes that live in similar habitats like spiny eels (Mastacembelidae), catfishes (various families) and snakeheads (Channidae). Perhaps the oddest thing we got was Garra fuliginosa, a strange little minnow with a long proboscis covered in tooth-like tubercles. Some species in the U.S. have similar tubercles, like the fathead minnow (Pimephales), but nothing like the gnarly forehead these guys have. At each site we had Zach Randall (UF) taking excellent photographs for a book he and Dr. Page are publishing on the fishes of the region. We also had Brooke's lab filming videos of the loaches walking – and boy can they walk (see video below). Brooke’s lab had an amazing set up of glass boxes, electronics, batteries, Legos and even a Steve Irwin doll – all for the sake of science.  

            I was shocked at how much convergence there was with some North American stream fishes - there are look-a-likes of our darters, minnows and sunfishes that are in distantly related Asian families. I had to sometimes ask the UF crew - are you sure that isn't Cyprinella venusta the spot-tail shiner that is ubiquitous in Louisiana rivers? Ironically, the “Rule of Life” we are studying for our grant was evolutionary convergence, but not between American and Asian stream fishes - but between the first fishes that came onto land in the Devonian 400 million years ago (and gave rise to all land dwelling vertebrates  i.e., tetrapods like birds and other reptiles, amphibians, and mammals) and these walking loaches that are the only other fishes to have developed strong bony connections between the vertebral column and the pelvic girdle as a convergently remodeled "hip." Throughout the trip Brooke's lab would come up with "Silly fishes hips are for kids" type of puns, which a bad dad-joke teller like me eats up like sugary breakfast cereal.

            Although we spent many beautiful afternoons walking through shallow streams in absolutely perfect weather (it was sunny in the low to mid-80s) the highlight of the trip was certainly our very first site. The day after we landed in Bangkok we got onto another plane (one not much bigger than a puddle jumper), this one took us near the Myanmar border in Northern Thailand to the subterranean home of the cave angel, Cryptotora thamicola. This species is actually the one that inspired Pam to become a cavefish biologist before she started graduate school.

Pam (an expert caver) and me (not an expert caver, but one that delights in them) and I have been thinking about this site for months. Information on this cave and species is sparse and we were given conflicting information. Nevertheless, we were excited to get to the site. With Zach and a number of our Thai colleagues we spent more than five hours crawling, bouldering and slipping in Maelana Cave. It was a beautiful place with lots of gorgeous formations, most spectacular was perhaps the waterfall where Cryptotora live. Seeing these fish in their natural habitat is one of the most beautiful things I’ve ever seen, but I must admit hearing Pam gushing over seeing these fish that have been her muse for so many years was even better. We would see a number of individuals in the fast-flowing water where they were all concentrated, and although we could not see over the waterfall there are presumably more below. Zach took videos that we will use to study how they “walk” and swim. Later when watching the videos, we learned that GoPro will add sound to them automatically; the techo-trance beat for one of the videos became the soundtrack of the fieldtrip.

Our 10-day trip was a success and the UF, NJIT, and LSU teams are all now back safe stateside getting geared up to collect data for our NSF Grant. Stay tuned as we learn more.

NSF uRoL:FELS:RAISE: A Phylogenomically-Based Bioinspired Robotic Model Approach to Addressing the Evolution of Terrestrial Locomotion