Peer review is
!!! NOT !!!
required for nomenclatural validity under the ICZN. (It will be under the PhyloCode.)
(Short digression: the notion that peer review is a basic component of science is much younger than many people think. Not only did nobody review Linnaeus, but Nature wasn't peer-reviewed till the 1970s, many small European journals weren't peer-reviewed into the 1990s, and edited books often still aren't AFAIK. Unlike with a preprint server, the editors read and reviewed the manuscripts, but didn't generally send them out to anyone else. Einstein got very angry once when he found out an editor had sent his manuscript to someone for review; he said he hadn't given the editor permission to send it to anyone, especially the person who got it.)
However, what kills the name is
ICZN Art. 8.5.3.2: "The entry in the Official Register of Zoological Nomenclature [ = ZooBank] must give an ISBN for the work or an ISSN for the journal containing the work." bioRχiv doesn't have an ISSN, so game over until the manuscript comes out in a journal that has one and is either printed or registered in ZooBank anew. Although not a nomen nudum (that would be specifically a name that fails
Art. 13, which is not the case here), the name is unavailable at present.