"Whether the two closely related fruitfly populations, designated Drosophila mojavensis and Drosophila arizonae, represent one species or two is still debatable among biologists"
And...
"biologists haven't been able to put their finger on just what initiates the reproductive isolation."
And...
"Further experiments demonstrated that the sterility trait is caused by more than one genetic change. "I think there are many genes--4 or 5 probably, maybe many more," Reed predicted."
And...
"There's a huge amount of biodiversity out there, and we don't know where it comes from."
Looks like there is still plenty of research to do.
Nawww, this is a done deal. It joins the "new" species, or "gonna be a new" species pool. This pool contains Nereid worms, primroses, Drosophila paulistorum et al., Lake Nagubago cichlids, mice somewhere in New England etc. etc. And then again there is "nothing new" under the sun.
A fundamental goal in speciation research has been to determine the number of genes that contribute to barriers to gene exchange (or reproductive isolating mechanisms) between closely related species. Recent studies of two particular barriers to gene exchange, hybrid male sterility and female species preferences, have found that these characters are often highly polygenic, with many regions of the genome being associated with at least some effect (for reviews see refs. 1-4). Hybrid male sterility appears particularly highly polygenic when segments of one species are experimentally introgressed into the genetic background of another and made homozygous (e.g., refs. 5 and 6). Perhaps the most extensively studied groups for these characters have been the two races of Drosophila melanogaster and the three species of the Drosophila simulans clade; D. simulans, D. mauritiana, and D. sechellia, although many other species (including non-Drosophila) have also been investigated. However, these species may be atypical of Drosophila species in particular or species in general, because all the hybridizations studied involved homosequential taxa: taxa not differing in their gene arrangements