Question

Astragalus and calcaneum are found in the
A. Hind limbs of the rabbit
B. Hind limbs of a frog
C. Forelimbs of rabbit
D. Forelimbs of frog

Answer 1

In the fibula and tibia the part of the crustorsal joint to be found in the attached bones of crus and also attached with the proximal tarsal bones and known by the name of astragalus and calcaneum.

Complete answer:
The presence of two elongated ankle bones of tarsals in the third division of the frog legs and also called as the name of astragalus and calcaneus. In the human talus, the part of the astragalus also be found, and in the heel bones of the human body the calcaneus to be found. It is formed a heel to which muscles can attach and ankle joint on the therian mammals that also known placental and marsupials and calcaneum has no contact with the tibia but crustorsal joint with the main joint of the ankle bending between the part of astragalus and tibia. Suchians are more closely related to avemetatarsalia as compared to phytosaurs according to the 2011 publication but the aforementioned crustaral joint evolved independently in suchians but did not get enough information to find out in the study of phytosaurs but mostly found in the ancestor's skeleton. The group of foot bones known by the name of tarsus and situated between the lower part of the ankle joint.
Therefore, the correct option is (B).

Note: Crustaral joint in the literature also known by the ankle joint of pseudosuchians and phytosaurs that mostly found in the calcaneus and astragalus. The part of the astragalus which fits into a socket in the calcaneus and mostly found in the skeleton of the phytosaurs.