Paralbula

Figure 7 R-U

Blake (1940) originally reported the genus from the Aquia Formation (lower Eocene) of Maryland. Current investigations, however, have revealed the presence of Paralbula not only in the Judith River Formation, Montana, but also in the Oldman Formation, Alberta. The teeth, which are fairly common in both formations, have been tentatively identified as belonging to? Paralbula sp. (Estes, personal commun.). The Judith River Formation specimens from Clambank Hollow are similar to those obtained from the Oldman Formation and consist of a mixture of thoroughly eroded to well-preserved teeth. The teeth vary in size and shape. Some are round, most are slightly convex, and a few are elongate or rectangular. AMNH 10100 has an average diameter of 2.5 mm. and AMNH 10101 has a length of 3.5 mm. (fig. 7 R-U). The attachment surface of the teeth is slightly concave and is characterized by a few concentric layers. The larger teeth comprise the central part of the pharyngeal plate, whereas the smaller, more rounded ones form the peripheral areas. The isolated occurrence of the teeth makes it impossible to decipher the arrangement in which the teeth were stacked, and hence makes comment on their affinity to phyllodonts inadvisable at this time. The affinities and relationships of the Alberta and Montana occurrences of Paralbula are currently under study by Estes, at Boston University.