Caridosuctor populosum
Fossil (top) and reconstruction (bottom) of Caridosuctor
populosum.
(Click on the fossil to view an enlargment.)
Caridosuctor populosum has the most derived anatomical features of any Bear Gulch coelacanth. It ranges from about 30 mm (2 1/4 inches) to 250 mm (10 inches) in length. It is the most common fish in the Bear Gulch bay. It has been found chiefly in the center of the bay, but the smallest individuals are only found in weedier, shallower areas.
The body is completely covered by thin, rounded, overlapping scales. Few but large teeth, thick lips, and a very large mouth suggest a suction feeder upon larger prey. One specimen was found with a paleostomatopod shrimp (Tyrannophontes acanthocercus) in its abdominal cavity, about 1/3 the size of the fish. The modern coelacanth Latimeria chalumnae has an electric detection apparatus in its snout with which to find food.
Caridosuctor posssesses a long, thick body, lobed and muscularized fins with widely spaced rays and delicate webbing, and a high-acceleration tail, indicating excellent maneuverability and poor speed or cruising capability.
There are two body shapes and sizes in Bear Gulch C. populosum: the larger and bulkier forms were probably females, the smaller and slimmer fish were probably males, as seen in the living coelacanth.
References:
- Lund, R., and W. L. Lund, 1984. "New genera and species of coelacanths from the Bear Gulch Limestone (Lower Carboniferous) of Montana (U.S.A.)." Geobios, 17, fasc 2: 237-244.
- Lund, R., and W.L. Lund, 1985. "Coelacanths from the Bear Gulch Limestone (Namurian) of Montana and the evolution of the Coelacanthiformes." Bull. Carnegie Mus. Nat. Hist. 25: 1-74.
- Lund, W. L., R. Lund and G. Klein, 1985. "Coelacanth feeding mechanisms and the ecology of the Bear Gulch coelacanths." Compte Rendu, Neuvième Congrès International de Stratigraphie et de Géologie du Carbonifère, 5: 492-500.