376 Appendix B
25. Reproductive Competition Species [RCC]
Definition: The most extensive units in the natural economy such that repro-
ductive competition occurs among their parts.
Principal Author: Ghiselin 1974, 1977.
Synonyms: Hypermodern species concept, Biospecies (in part).26. Synapomorphic Species [SySC]
A phylospecies conception.
Definition: The least inclusive taxon recognized in a classification, into which
organisms are grouped because of evidence of monophyly (usually, but not
restricted to, the presence of synapomorphies), that is ranked as a species
because it is the smallest “important” lineage deemed worthy of formal
recognition, where “important” refers to the action of those processes that
are dominant in producing and maintaining lineages in a particular case
(Mishler et al.). A species is a lineage separated from other lineages by
causal differences in synapomorphies (Wilkins).
Principal Authors: Mishler and Brandon 1987, Mishler and Donoghue 1982,
Wilkins 2003.27. Successional Species [SSC]
Definition: Arbitrary anagenetic stages in morphological forms, mainly in the
paleontological record.
Principal Authors: George 1956, Simpson 1961.
Synonyms: Paleospecies, evolutionary species (in part), chronospecies.28. Taxonomic Species [TSC]*
Definition: Specimens considered by a taxonomist to be members of a kind
on the evidence or on the assumption they are as alike as their offspring of
hereditary relatives within a few generations. Also: Whatever a competent
taxonomist chooses to call a species.
Principal Authors: Blackwelder 1967, but see also Regan 1926, Strickland
et al. 1843.
Synonyms: Cynical species concept (Kitcher 1984).
Related Concepts: Agamospecies, genealogical concordance species, morpho-
species, phenospecies, phylospecies.Replacement Conceptions
Several so-called species conceptions are in fact replacement concepts that displace
species. Some (e.g., LITUs) are intended to replace species entirely; others are paral-
lel concepts that are neutral regarding species.