When we receive queries for identification of skulls or specimens, we turn to our large specimen collection to find those that look similar and may help in the identification process. Among other osteological features we can look at the proportions of the skull, along with the size, number and spacing of the teeth. All these features of a recently received picture of a specimen in question led me to suspect that the specimen is foreign to the Great Lakes, and based on the very small size of the specimen I suspected that it may be a Round Goby. Following I will show you some of the specimens I looked at to bolster my conclusion.
Let’s start with a picture of a Round Goby from our collection:
Note the width of the skull, and the abundance and spacing of the teeth on this specimen.
The species that I considered to have the skull that would most closely match the proportions of the putative goby skull was the Central Mottled Sculpin.
But here you can see that the head of the Mottled Sculpin is actually wider than, and the teeth proportionally not as large as those of the Round Goby (there are several other skeletal differences but those sufficed for this diagnosis).
There are several native fish that are carnivorous and have caniniform or cardiform (small, numerous and closely spaced) teeth that I mused over, but as you can see almost all of those have much narrower skulls and/or have shorter, fewer and more widely spaced teeth than the skull in question.
Note: The Sauger, very close in appearance to the Walleye, was once abundant in Lake Erie but is now caught very seldom in the lake and its tributaries.
As you can see there is nothing quite like the Round Goby among our native species, and we should no doubt be thankful for that!
Let us hope that the situation remains the same, and in the meantime, if you find a good use for these little monsters feel free to apply it and let us know your ideas.
About the Author: Marc Kibbey is Associate Curator of the Fish Division at the Museum of Biological Diversity.