Zaglossus robustus 

Zaglossus robustus is an extinct species of long beaked echidna. It is known from the middle Miocene which is approximately 13 to 14 million years ago and is known from Gulgong, New South Wales, Australia (Musser, 2003). This species may  belong in the genus Megalibgwilia. This species is known from a fossil skull about 65 cm long. It had many spikes along its back to protect it from its predators and used them as a weapon.

References

Musser, A. M. (2003). "Review of the monotreme fossil record and comparison of palaeontological and molecular data". Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 136 (4): 927–942. doi:10.1016/S1095-6433(03)00275-7.