| Abstract: | Klein, W., Böhme, W. and Perry, S. F. 2000. The mesopneumonia and the post‐hepatic septum of the Teiioidea (Reptilia: Squamata). —Acta Zoologica (Stockholm) 81 : 109–119 This study investigates the structure of the pleuroperitoneal cavity of Teiioidea. Seven of nine genera of Teiidae and eight of 35 genera of Gymnophthalmidae were dissected and the results are presented in a highly schematic two‐dimensional representation. The main anatomical differences between the two families are (1) the presence of a hepatic ligament which fuses with the pericardiaco‐peritoneal septum in the Gymnophthalmidae but not in the Teiidae; (2) the presence of a ventral mesopneumonium on the right side in the Gymnophthalmidae, while this structure is secondarily lacking in the Teiidae; (3) that the post‐hepatic septum of Teiidae consists of a bipartite hepatic ligament and the ventral mesentery, while in gymnophthalmids the hepatic ligament remains undivided. Neusticurus and Echinosaura completely lack a post‐hepatic septum. The results are consistent with the hypothesis that the Gymnophthalmidae are primitive within the Teiioidea and that the Tupinambinae are the most highly derived teiids. We propose that the post‐hepatic septum may restrict passive visceral movement during breathing, thereby increasing the efficiency of respiratory effort; a modification that could benefit the fitness of active, predatory teiids. |
