Dear Mary Sue, sp. nov. means species nova (new species)... when an author uses it without giving a formal name it usualy means that the material at his disposal suggests that the species is a new one but is not sufficient to create the new species and typified it... I have done that myself at many occasions in the fossil world... It can happen that in the same publication a series of specimens can be refered as sp. nov. A, B, C, or 1, 2, 3. In any case it means that the specimens pends a more dedicated study... Hope it helps, Luc