A Marine Stem-Tetrapod from the Devonian of Western North America
Figure 5
Glenoid fossae and pelvic limbs of select stem-tetrapods.
Glenoids are illustrated in posterior view and highlighted in blue, fibulae are highlighted in green. The glenoid of Tiktaalik is depicted from two different perspectives, posterior view (above) and posteroventral view (below). The largest Tiktaalik specimens are more oblate, which may be autapomorphic relative to the condition in more crownward Devonian and Carboniferous taxa. The glenoid of Panderichthys was based on the shape of its caput humerus. See text for additional details. The in-plane glenoid measurement (height at maximum extent divided by maximum length) diagnoses an elongate glenoid fossa: Medoevia = 0.60; Eusthenopteron = 0.60; Tinirau = 0.42; Panderichthys = 0.48; Tiktaalik = 0.44; Acanthostega = 0.45.