Scientists Find Second Crocodile Species in New Guinea, Thought to Host Only One

Discovery based on skulls sitting in museum for 90 years

Caleb McMahan examining crocodile skulls in the Field Museum's collections. The one in his left hand is C. novaguinea, and the one in his right is the new species, C. halli.
Kate Golembiewski, Field Museum

A new species of crocodile has been identified after two scientists picked up a deceased colleague’s project and concluded that the island of New Guinea has not one species of the giant reptile, but two.

Identification of New Guinea Crocodile 2.0 was based on skulls that had been moldering in a museum for 90 years, explain the scientists in the journal Copeia, the publication of prestige for icthyologists and herpetologists. With hindsight, the researches realized the bones bore marked differences compared with the crania of the other New Guinean croc.

Later, having traveled to see the beasts live, Chris Murray, Assistant Professor at Southeastern Louisiana University, and Caleb McMahan, scientist at the Field Museum, had to admit that in life, they look different too.

Decently, the newly acknowledged crocodile has been named Crocodylus halli, for the man responsible for realizing it was there: Philip Hall of the University of Florida.

The story begins in 1928, when science realized that the New Guinea crocodile was distinct from other southern hemisphere crocs. Some time after that, the thought arose that the crocodiles in the island’s north and south were not the same.

This matter was being investigated by Hall, who died – but first, identified key differences in the way the two groups of crocodiles nest and mate.

“Chris does a lot of work on crocodilians, and I do a lot of evolutionary work, often with morphology, or the animals’ physical features. Chris studies morphology too, so it was continuing along with a lot of the projects we were doing, but then lo and behold, it’s this brand new crocodile species,” said McMahan, a senior author of the paper.

The long and short of it is that McMahan and Murray analyzed 51 skulls from seven different museum collections that had been thought to all belong to Crocodylus novaeguineae, and lo, they did not.

Murray begs to note that studying crocodiles in the form of skulls on museum shelves is quite the convenience compared with analyzing the living, breathing version: “which would have been incredibly difficult anyhow, and very expensive.”

New species of crocodile discovered in museum collections.
American Society of Ichthyologis

Good point, that. However, as nothing should be taken for granted in science, they then traveled to observe live specimens – in Florida. It is easier, cheaper and presumably safer to examine crocodiles at the Alligator Farm Zoological Park (“The Zoo for You”) in St. Augustine than to paddle through the swamps of New Guinea.

“They have live individuals of what’s called novaeguineae, and we were able to look at those and say, ‘Oh yeah, this matches the north and this matches the south!’ I thought that was super cool,” McMahan stated.

Having studied the skulls ad nauseum, the distinctions between the two species of New Guinean croc were glaring, they say.

“We could even look at a skull that they had there and tell what river it came from,” Murray claims.

Hall’s crocodile isn’t the biggest unknown species to have been lurking there in plain sight. That distinction could reasonably go to the tree Incadendron esseri which can loom 100 feet in height, which remained unnoticed in the cloud forest of the Andes mainly because it was off the beaten track. Or the beaked whale Berardius minimus – about which Japanese whalers had known all along.

The case of the croc is more like that of the whole collection of newly recognized horseshoe bats: which had been assumed to be a single species, and were not. The same goes of the electric eel, a monster of the Amazon that can reach 8 feet in length and also turned out to be multiple species, not one.
The newly acknowledged halli crocs from the southern end of the island have shorter, broader snouts than the familiar novaguineae crocs from the northern part.