There are two main differences between the Charya Tantra form of Bhutadamara and the Anuttarayoga form of the deity. First, the Charya iconography has the deity standing atop an elephant headed Vighnantaka. In the Anuttarayoga iiconography he stands atop Aparajita with a wrathful rakshasa face. The principal Charya form of the Bhutadamara, also found popularized in the Vajravali of Abhayakara Gupta, describes a thirty-three deity mandala. The Anuttarayoga form is a solitary deity without a detailed mandala or any retinue figures.
Artists are not always clear when making the distinction between Vighnantaka and Aparajita beneath the feet of Bhutadamara, however the number of deities in the mandala is unmistakable. Religious and traditional context is also important when identifying Bhutadamara.
Jeff Watt 7-2013
Toh 747. The Bhūtaḍāmara Tantra (Bhūtaḍāmaratantram, འབྱུང་པོ་འདུལ་བའི་རྒྱུད། · ’byung po ’dul ba’i rgyud). 84000: Translating the Words of the Buddha.