[Taxacom] "sp. nr." in name

[Guanyang Zhang]

Dear all,

I've recently come across "sp. nr." in names.  For example, Geolaelaps sp.
nr. aculeifer (Canestrini) (Acari: Laelapidae) (Source
<https://www.cambridge.org/core/journals/canadian-entomologist/article/biological-control-of-fungus-gnats-bradysia-spp-diptera-sciaridae-and-western-flower-thrips-frankliniella-occidentals-pergande-thysanoptera-thripidae-in-greenhouses-using-a-soil-dwelling-predatory-mite-geolaelaps-sp-nr-aculeifer-canestrini-acari-laelapidae1/CE688E27B47A3747F1A2328A3984F823>
)

This appears to be uncommon. In nearly all insect determination labels I've
seen, if the identifier isn't sure about the identification, either nr. or
cf. could be used, but without sp., which seems redundant. A colleague of
mine argues that "sp." is needed to make the name binomial. Not sure if I
see the point of doing that for species with doubtful identification. Any
thoughts? Thanks.

Best,
Guanyang