outer edges. This is in notable contrast to all early amniotes, in which this area possesses an outward prong (known as a 'transverse flange') which is covered with teeth. Further preparation of the skull to reveal this feature of the palate is one of the primary reasons why Westlothiana's classification was reworked to belong outside Amniota. Postcranial skeleton The body is elongated, with about 36 to 40 vertebrae between the skull and the hip. No known specimen of Westlothiana preserves a complete tail, so the length of that region is unknown. The vertebrae of the body are multi-part bones, primarily formed by a large pleurocentrum bone at the rear of each segment, with a smaller intercentrum at the front of each segment. Vertebrae which possess this format are defined as "gastrocentrous". The pleurocentra are spool-shaped cylinders, pierced by a large canal for the spinal cord and fused to low, triangular neural spines. The intercentra are crescent-shaped, and despite being smaller than the pleurocentra, they are relatively large compared to those of most amniotes and advanced reptiliomorphs. Overall the vertebrae of Westlothiana most closely resemble those of the early sauropsid Captorhinus, although the short neural spines are more similar to lepospondyl vertebrae. However, the vertebrae also possess a unique feature not shared by any other reptiliomorphs. This feature is the presence of several large keels which run along the underside of each pleurocentrum. Although keels also run along the underside of the pleurocentra in synapsids, these keels are much closer to the midline in members of that group compared to in Westlothiana. The ribs of Westlothiana connect to the intercentra, and are present in every vertebra between the skull and the hip. The forelimb was significantly shorter than the hindlimb, a characteristic shared with lepospondyls. The only well-preserved portions of the shoulder girdle were the scapulocoracoids (shoulder blades), which were large and robust. The humerus is simple and thinnest in the middle, more similar to microsaurs and early amniotes rather than larger tetrapods. The ulna is similar to that of gracile "pelycosaurs", including small species of Dimetrodon such as D. milleri. Although the hand of Lizzie was disarticulated, four metacarpal bones could be identified. This indicates that members of Westlothiana possessed at least four, and possibly even five fingers. Practically all other reptiliomorphs possessed five-fingered hands, except for the majority of lepospondyls. Lepospondyls (with the exception of Diceratosaurus and Urocordylus) possessed