There is no such species as a "false julii," and it would be better if hobbyists used the actual scientific names of a cory and not the made-up common names which are without question very confusing. Ian Fuller will ban people from his webiste if they use common names and especially "false julii." I am certainly not suggesting people be banned on TFF for this--though it might be advantageous!--but the point has to be understood that common names are rarely helpful and really should be forgotten. The common name "leopard" which was mentioned in this thread is only adding further confusion, as will be obvious from what I write below.
Corydoras julii is very rarely imported. In North America, and in the UK it would seem from what
@Essjay posted, the vast majority of the fish labelled as
C. julii are in fact
C. trilineatus which is a distinct species with no more connection to
C. julii than that of being a species in the polyphyletic genus
Corydoras in the family Corydoradinae. The distinctive patterning especially on the head of each of these two species is usually a clear distinction as to the species.
Corydoras julii, C. leopardus, C. punctatus and
C. trilineatus all share a large black blotch in the dorsal fin, a barred caudal fin, and a horizontal stripe along the body at the juncture of the dorsal and ventral lateral plates; the body is spotted, and this is distinctive with respect to
C. julii and
C. trilineatus. However, all these species are highly variable in their pattern, and the horizontal stripe may be absent in
C. julii.
C. leopardus is noticeably larger (at maturity) than the other three, and is in a different lineage (Lineage 8) from the other three which are in Lineage 9 so more closely related to one another as they all descended from the same common ancestor (
C. leopardus having descended from a different ancestor).
www.seriouslyfish.com
