Found a blog where they discuss this in some depth. Might as well give you the exact quote:
"Uromastyx" is the name of the genus. There is only one genus named Uromastyx so there is no plural. You do not pluralize scientific terms for genus, species, or subspecies. Sometimes when the common "English" name is the same as the scientific it is acceptable in common terms to pluralize, but scientifically speaking it is wrong.
Example: 2 specimens of I. iguana iguana, or commonly spoken 2 green
iguanas. However to say 2 uromastikes makes you sound like you are
trying to sound more intelligent than what you really are; inventing
words and such. No one says that.
From Reptic Zone.
Based on this quote, I searched for formal/correct ways to pluralize scientific names. Finding the following(AnimalDiversity.org):
Scientific names can be regarded as either singular or plural, so it
would be equally correct to say "Canis lupus [has or have] eight
pups per litter." Since taxonomic entities are considered evolutionary
individuals, we generally prefer that scientific names be regarded as
singular, such as "Myotis keenii is found in Pacific coastal
And this(Proper Usage of Terms and Scientific Names):
To refer to members of a given genus in the plural sense, using
Bacillus, Micrococcus and Mycobacterium as examples, one cannot change
the genus name directly to a plural form. Bacilli, Micrococci and
Mycobacteria would be improper. To get around the problem, one can
write such as the following examples: "species of Bacillus," "isolates
of Micrococcus," "strains of Mycobacterium."
So technically, using the term "Uromastyx" as a plural form should be okay. Since there is not plural form of a genus name.