Complex sentence: The Diarthrognathus is of interest mainly because it possesses a jaw structure that is similar to both mammals and reptiles, with a reptilian joint between the quadrate and articular bones in addition to the mammalian joint between the squamosal and dentary bones.
Split into simpler sentences: The Diarthrognathus is of interest mainly because it possesses a jaw structure that is similar to both mammals and reptiles. Its reptilian jaw joint is located between the quadrate and articular bones, and its mammalian jaw joint is located between the squamosal and dentary bones.