give more height or more range (see photo), so vertical clinging and leaping animals adjust their launch angles accordingly to compensate for this. Fossil evidence Locomotor adaptations in Eocene prosimians There is evidence of vertical clinging and leaping adaptations in the postcranial skeleton of early Eocene fossils of prosimians. Lacking any common quadrupedal features, the postcranial bones and fossils of the Eocene prosimians most closely resemble the specializations of vertical clingers and leapers. Common morphological elements identified in these early fossils include a high phalangeal index, low intermembral index, femurs with cylindrical head and high, narrow patellar grooves, and fused fibula and tibia. The high phalangeal index is the elongation of the phalangeal finger bones, which helps vertical clingers who require increased prehensile power in their hands to support their large bulk. The low intermembral index is the total length of the humerus and radius in percentage of total length of the femur and tibia. The features of the femur is part of an evolution of elongated femurs that helps the primates' extreme range of flexion and extension, which allows them to perform their leaps. Thus, VCL seems to be the only known locomotor adaptation in the Eocene primates, meaning it is one of, if not the earliest, locomotor adaptations. Early Eocene primate fossil: Ida The earliest evidence of VCL can be found in an early Eocene adolescent primate, named Ida. She exhibited legs that were longer than her arms, suggesting that leaping was a key aspect of her locomotion. Her death is hypothesized to be linked to her vicinity to the Messel Pit, near Frankfurt, Germany. The hot magma from the earth mixing with the underground water tables led to explosions that released toxic gasses. Ida was found with a broken wrist, and it is believed that due to this, she could not leap or cling to the higher tree branches, and therefore had to stay lower to the ground where she came into contact with the toxic gasses and died. References Arboreal locomotion