Harpagofututor volsellorhinus
Female (top) and male (top) fossils of Harpagofututor volsellorhinus.
This eel-shaped holocephalan is related to the cochliodonts, and more distantly to the chimaeroids. It is most closely related to a slightly older Scottish Carboniferous fish, Chondrenchelys problematica. It is known to range up to about 8 inches in length. It is common and ubiquitous, particularly in the central bay.
Harpagofututor is eel-shaped, with a very long, low dorsal
fin, lobed pectoral fin bases bearing delicate paddle-like fins, and
pelvic fins that are larger in males than females. Like most
anguilliform fish, swimming would involve slow maneuvering by dorsal or
pectoral fin undulation, and escape acceleration by whole-body motion.
There are no scales.
There are two small and one large pair of relatively delicate upper
tooth plates, and one median, one small pair and one large pair of
lower tooth plates for breaking shelled foods.
Sexual dimorphism:
Males have bony, muscularized, denticulated, crab-claw-like structures that articulated with the upper surface of the ethmoid part of the braincase. These structures were not just ornamental. They were probably used to hold females or display against other males. The Scottish relative, Chondrenchelys, lacks these ethmoid claspers; but males have enlarged, stiffened pectoral paddles, probably for display purposes.
References:
- Grogan, E. D. and R. Lund., 1997. "Soft tissue pigments of the Upper Mississippian chondrenchelyid, Harpagofututor volsellorhinus (Chondrichthyes, Holocephali) from the Bear Gulch Limestone, Montana, USA." Journal of Paleontology 71:337- 342.
- Lund, R. 1982. "Harpagofututor volsellorhinus new genus and species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean) and their sexual dimorphism." J. Paleo. 56: 938-958.