I read in a reference book on Google Books (Biology of Termites: a Modern Synthesis, eds. Bignell, Roisin, and Lo) that the termite Heterotermes perfidus found on the South Atlantic island of St Helena is a "valid species":

Gay states definitively that "there is no doubt now, however, that H. perfidus is a valid species ..." (p. 537)

I don't understand what "valid species" means.


"Valid" in this case is just emphasizing that the Heterotermes perfidus on this island are a different (real) species, and not just a variation of their closest relatives. You need not get bogged down with how we determine species, or define species. It just means that this taxon (named group) exists as a separate species: a "valid" species, based on differences that some taxonomist deemed important enough to describe and give a name. Others may disagree, and write a paper to synonomize it (sink it into another existing species), but that is part of the messy business of taxonomy.

  • $\begingroup$ Many thanks, that is most helpful. $\endgroup$ – user8654 Aug 23 '19 at 20:47

This will vary from discipline to discipline. In paleontology valid species means a population that can be show to be morphologically distinctive in a way that cannot be better explained as sexual dimorphism or a growth distribution. In a living species it may rely on genetic (breeding) isolation.

Basically a "valid" species is meant to show it as distinct from a provisional species or subspecies. Generally the null assumption is that two populations are the same species unless evidence can be presented to show otherwise.The author is saying they have presented such evidence and this really is a distinct species.

  • $\begingroup$ Thank you very much. $\endgroup$ – user8654 Aug 24 '19 at 21:04

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