Stages of Development and Sequence of Bone Formation in the Little Brown Bat, Myotis lucifugus

Developmental stages of Myotis lucifugus are described and data on the sequence of post-cranial skeletogenesis are provided. A total of 27 embryonic, juvenile, and adult M. lucifugus was weighed and crown-rump length measured. Developmental stages were determined by use of external morphological characteristics and sequence of bone formation of the post-cranial skeleton was determined on cleared and differentially stained individuals. Weight is a less variable character than crown-rump length within each developmental stage, development of external characteristics correlates with skeletal formation, and osteogenesis first appears in the humerus, radius, ulna, femur, tibia, and fibula.