A NEW LATE PENNSYLVANIAN COELACANTH FISH FROM KINNEY QUARRY, CENTRAL NEW MEXICO

The Late Pennsylvanian Kinney Quarry in central New Mexico is a Lagerstatte known for it diverse and abundant fish fauna, especially of palaeonisciform and acanthodian fishes. Coelacanths are a rare component of the Kinney fish fauna. Of the 395 fishes collected, only 17 specimens from the Kinney quarry are coelacanths, of which, only four are nearly complete. These four specimens represent two distinct taxa. One is an indeterminate coelacanth showing affinities to both Rhabdoderma and Coelacanthus based solely on postcranial morphology. New Mexico Museum of Natural History(NMMNH) P-31392 and NMMNH P-29379 represent a new coelacanth species. The small individual P-31392 is interpreted as a juvenile and shows few postcranial ontogenetic differences from the larger P-29379. This species closely resembles Cardiosuctor populosum, from the Mississippian Bear Gulch Limestone, especially in the overall shape, position, placement and ornamentation of the cranial bones. Unlike Cardiosuctor, the Kinney coelacanth lacks teeth on the dentary and has a large plate of dermal armor anterior to the first dorsal fin. These two fish have similar morphology in the unique shape of the fin girdle that is not seen in any other rhadbodermaform coelacanths. Although these two fish show a unique shape of the pelvic fin girdle, the girdle of the Kinney coelacanth has five major and no minor anteriolateral processes, whereas Cardiosuctor has three major and one minor anteriolateral. The medial process of the pelvic girdle is similar in both fish. The basal process is lobate in Cardiosuctor and rectangular in the Kinney coelacanth. In the Kinney coelacanth, the medial and basal processes form a straight line posterior to the anteriolateral processes, whereas in Cardiosuctor these two processes form a L shape posterior to the anteriolateral processes. The Kinney quarry is a brackish water lagoonal setting, with the coelacanths being restricted to the more marine parts of the section. This is congruent with C. populosum, which is a marine restricted coelacanth.