How are Obregonia and  Trichodiadema different from each other?
Trichodiadema Trichodiadema is a genus of succulent plants of the family Aizoaceae.
Ascaridida The order Ascaridida includes several families of parasitic roundworms with three "lips" on the anterior end. They were formerly placed in the subclass Rhabditia by some, but morphological and DNA sequence data rather unequivocally assign them to the Spiruria. The Oxyurida and Rhigonematida are occasionally placed in the Ascaridida as superfamily Oxyuroidea, but while they seem indeed to be Spiruria, they are not as close to "Ascaris" as such a treatment would place them.