[2] All species except the cave-dwelling South African Speleosiro argasiformis spend their entire life cycle in leaf litter.

Although all Pettalidae except Parapurcellia have eyes, these were long thought to be absent in the family, mainly because they cannot be seen by scanning electron microscopy.

[1] Parsimony analysis suggests it could be a sister group to the remaining Cyphophthalmi, though this could also be the case for the Stylocellidae,[1] or it could be related to the Sironidae, or specifically to the sironid genus Suzukielus.

Pettalidae were likely present throughout the forests of Antarctica, which formed a land bridge between Australia and South America up until circa 50 million years ago (mya).

Likewise, the monotypic Neopurcellia from New Zealand appears as the sister group to all Pettalidae except for Parapurcellia, instead of being monophyletic with the other two New Zealand genera, which themselves appear as sister groups in Bayesian analysis, but not in direct optimization parsimony analyses.