This is pretty cool, Neanderthals are from Paranthropus. Look here:

rib cage of Paranthropus, including P. neanderthalensis, conical

rib cage of Australopithecus and Homo, cylindrical

and the two lineages (Paranthropus and Australopithecus) speciated as early as 6 million years ago, shown by data from Popadin et al^[1] last year

for reference, here is KSD-VP-1/1, "Kadanuumuu", 3.58 million years old Australopithecus afaransis, that clearly shows that the human rib cage pre-dates all Paranthropus fossils, including Paranthropus neanderthalensis and Paranthropus deyiremeda from 3.5 million years ago^[2].

References

1. Mitochondrial pseudogenes suggest repeated inter-species hybridization in hominid evolution

2. New species from Ethiopia further expands Middle Pliocene hominin diversity
   

The species tree, building on the data from Popadin et al,