A B S T R A C TTyler, James C, and

A B S T R A C T
Tyler, James C, and Alexandre F. Bannikov. A Remarkable New Genus of Tetraodontiform
Fish with Features of Both Balistids and Ostraciids from the Eocene of Turkmenistan.
Smithsonian Contributions to Paleobiology, number 72, 14 pages, 4 figures, 1 table, 1992.—A
new genus and species of tetraodontiform fish, Eospinus daniltshenkoi, is described from the
Lower Eocene of Turkmenistan (Danatinsk Formation). It is referred to the Balistoidea because
it has three large dorsal-fin spines; the pelvic fin reduced to a rudimentary but prominent
structure apparently composed of two partially fused spines at the posterior end of the pelvis; and
enlarged scale plates that form an incomplete carapace or loosely articulated armature around
much of the body. It differs from all other balistoids in having a long median spine projecting
forward from the snout and another spine projecting posteriorly from the middle of each side of
the body; lower jaw teeth twice as long as the upper jaw teeth; and in lacking encasing scales
around the rudimentary pelvic spine. Eospinus is the first record of a balistoid fish from the
Eocene with three dorsal-fin spines and the pelvic spines fused together at the end of the pelvis,
as otherwise only occurs in balistids, which are first recorded from the Oligocene.
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