I know that there isn't although we cannot deney the fact that when you have a toy that is under 4 lbs the so called public calls them "T-Cups" I didn't invent the name.
I guess you could say "Tiny" I personally do not believe in any runts like pocket puppies that weigh 1lb at adult weight. My girl is 4 lbs and my male is 3lbs. Sorry if some breeders are offended but I have a lot of inquiries for a small stud , so how else can I describe him? you tell me. I am an established breeder and plan on showing my female as her father is champion in Canada.