Updated March 13, 2015 with a new palate figure based on the photo, not the original drawing in Effigia and Shuvosaurus was modified in turn.
Effigia okeeffeae (Nesbitt and Norell 2006, Nesbitt 2007) Carnian, Late Triassic, ~210 mya, ~ 2 m in length, was originally considered an early theropod dinosaur by Colbert, who collected the specimen in the late 1940s but never removed it from its jacket. A recent reassessment by Nesbitt and Norell (2006) and Nesbitt (2007) nested Effigia among the poposauridis. It is an odd bipedal poposaur and perhaps the most derived member of a clade composed almost entirely of odd derived members. The reconstruction of the skull has been controversial. Perhaps only a direct tracing and shifting of the elements can solve this puzzle. All the pieces in the disarticulated fossil will come together precisely if they are correctly reassembled.
It is possible that the palatine (Fig. 2). was misidentified originally as the right ectopterygoid. If so, then the palate resembles that of known sister taxa, like Shuvosaurus (Fig. 3)..
Due to the long premaxilla
and the short maxilla the Effigia palate shifts most of the palatal elements into a smaller space. Even so all maintain their original and typical connections to the other skull elements.
You really can’t talk about
the palate of Effigia without comparing it to its sister, Shuvosaurus (Fig. 3). Here the main triangular part of the pterygoid must be imagined, but the quadrate processes are present and quite robust. The palatines frame the internal nares posterior to the palatal processes of the maxilla and premaxilla.
The above image (Fig. 4, Nesbitt 2007) is a CT scan of the Effigia occiput colorized to aid identification of the elements. The occiput is so inclined it is almost continuous with the palate. Originally the supraoccipital + opisthotics were identified as the two parietals with no median element recognized. Neither the supraocipital or the opisthotic were identified otherwise.
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AMNH Effigia webpage
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