Rough-toothed Dolphin video



Erich Fitzgerald: What we’ve discovered here at Mallacoota in eastern Victoria is a Rough-toothed Dolphin. Rough-toothed Dolphins get their name from the rugosities or ridges on their teeth on the actual enamel. And that’s interesting because it’s a diagnostic feature of this particular species.

There’s a few other species that Rough-toothed Dolphins have unlike any other dolphin species that allow us to identify this particular individual as a Rough-toothed Dolphin.

Rough-toothed Dolphins are interesting because they are generally poorly known worldwide and especially poorly know in Australia and barely known in Victoria. This is only the second in Victoria of a Rough-toothed Dolphin ever recorded from Victoria.

So we can see that the Rough-toothed Dolphin has many many teeth in its jaws and that’s kind of interesting. That shows us one of the key differences between these marine mammals and us land-living mammals. Dolphins have many many many more teeth in their jaws than any mammal that lives on land.

Kate Charlton-Robb: Some of the more interesting morphological characteristics of a Steno is the sloping head here. So unlike a lot of Bottlenose Dolphins that are classic where you see they have a beak or a rostrum that’s defined by the cape that goes up into the melon, the Steno here has a gradual slope that goes down into, from the beak up into the melon there. It also has relatively large eyes for a dolphin.

We’ll have a look at things. It has interesting skin lesions on here and we’ll have a look at histopathology with what they could potentially be. It might be that it’s just a fungal or a bacterial infection or it could indicate some kind of pathological disease. Interestingly they had whale lice in them so that might also impact on why they look the way they do.

Generally dolphins and whales strand for a reason. This animal was tried to be refloated but it came back in and it was swimming in circles. So that would indicate to me that there is some kind of compromised aspect to it, again whether that’s because it was not in subtropical or tropical waters, it was in much colder waters down here in Victoria. But equally we’re interested in having a look at markings around the head, in that there is what could be an entanglement around the head, which could have it compromise the animal. But again, it’s at the base of the head and it might also indicate a crease of where there has been some, you know, the articulation point between the skull and the rest of the body. So we’ll have a look at, do cross-sections in those areas and see if it’s just impacted just on the skin region or if it’s actually gone a little bit further down.

About this Video

Erich Fitzgerald and Kate Charlton-Robb talk about Rough-toothed Dolphins just before the necropsy of an animal that washed up at Mallacoota.
Length: 2:58