Did the Buddha speak the Mahanidana Sutta in the Digha Nikaya?

In the Pali suttas, there are scores of suttas about Dependent Origination which take the classic form of the 12 links, the benchmark being SN 12.2. In the Digha Nikaya, there is the Maha-Nidana Sutta, called the 'Great Cause'. I find the name of the sutta strange since if it is 'great', why are there only 9 links instead of 12? While there are many suttas containing less than 12 links, it seems strange the Maha-Nidana Sutta omits the six sense spheres, which the Buddha described as one of his core teachings in AN 3.61 & are central to so many suttas on Dependent Origination (such as MN 18, MN 38, MN 148, etc). More importantly, the Maha-Nidana Sutta defines consciousness & nama-rupa differently to other suttas. In the Maha-Nidana Sutta, consciousness (which is only *mental cognition* in other suttas) is said to descend into the womb of a mother. Nama-rupa has a Brahmanistic meaning of 'naming-forms'. Also, 'birth' refers to the birth of different animals & creatures rather than the birth of "beings" or "satta". SN 23.2 refers to a "being" as a mind that is attached to the five aggregates as "self". It is doubtful birds & snakes conceive the five aggregates as "self" or generate "self-views" of "beings" (as described in SN 5.10). Are there any compelling reasons or grounds why Buddhists should accept the Maha-Nidana Sutta of the Digha Nikaya as the words of the Buddha?