Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The rod-like interclavicle of Ophiacodon (a Permiansynapsid) connected to a pair of rounded clavicles. Seen in ventral view (i.e. looking towards the chest from below)
An interclavicle is a bone which, in most tetrapods, is located between the clavicles. Therianmammals (marsupials and placentals) are the only tetrapods which never have an interclavicle, although some members of other groups also lack one. In therians, it is replaced by the sternum which is similar in shape and function but forms via endochondral ossification (cartilage forming bone). The interclavicle, on the other hand, develops through intramembranous ossification of the skin.
