Walking Sharks Explained: A PhD Candidate's Path to a New Species

Walking sharks are one of the strangest small predators on the reef: pectoral fins built for crawling across coral flats at low tide, distributions so narrow some species live in a single bay, and a family tree that's still being filled in. In this episode, Andrew Lewin and Dr. David Ebert are joined by Jess Blakeway, a PhD candidate at the University of the Sunshine Coast, whose research on the distribution, ecology, and biology of walking sharks (genus Hemiscyllium) in Papua New Guinea has already led to a new species discovery. Jess walks through her path from volunteering with sea turtles in PNG to noticing a walking shark outside its known range, emailing shark scientist Christine Dudgeon out of the blue, and eventually joining her as a PhD student. That relationship led to the description of Hemiscyllium dudgeonae, or Dudgeon's walking shark, named in honor of her supervisor. Jess and the hosts also dig into why these sharks have such tiny, non-overlapping ranges, how researchers tell nearly identical-looking species apart using color pattern, genetics, and geography, and the ongoing mix-up between "zebra sharks" and "leopard sharks," which turn out to be the same animal at different life stages. It's a fun, detail-rich conversation about what it actually looks like to find a new species in the field, what happens after that moment (specimen collection, museum deposits, taxonomic description), and what Jess has planned for her postdoc research. Takeaways: Papua New Guinea and northern Australia are home to all 10 known species of walking shark, each with a highly restricted range shaped by deep-water barriers, freshwater outflows, and shallow-water habitat limits. Jess Blakeway co-described Hemiscyllium dudgeonae, a newly recognized walking shark species named after her supervisor Christine Dudgeon. Because walking sharks look nearly identical morphologically, researchers rely on color pattern, genetics, and geography, not body shape, to tell species apart. Zebra sharks and leopard sharks are the same species (Stegostoma tigrinum): striped as juveniles, spotted as adults. Some walking shark distributions overlap without the species actually co-occurring, raising open questions about how isolation and reef geography shaped their evolution. Connect with us: Website: https://bit.ly/37TMqeKInstagram: https://bit.ly/3eorwXZ YouTube: https://www.youtube.com/@beyondjawspodcast7591 Dave:  Website: https://www.lostsharkguy.com/ Instagram: https://bit.ly/3q1J9Q5 YouTube: https://www.youtube.com/@lostsharkguy Andrew: Website: https://www.speakupforblue.com/ Instagram: https://bit.ly/37g5WkG YouTube: https://www.youtube.com/@SpeakUpForBlueTV