Replies

Criterion or circumstances	Biological Species Concept	Morphological Species Concept	Phylogenetic Species Concept	Genetic Species Concept
1. Diagnosably distinct populations recognized as a separate species	Sometimes	Most times	Always	Yes, if genetic distances are typical of sister species
2. Species unit often includes diagnosable allopatric populations	Yes, subspecies concept widely accepted	Yes, subspecies concept widely accepted	Never, subspecies concept not relevant	Yes, subspecies relevant but defined genetically
3. Species represent terminal taxa that can be used in phylogenetic and biogeographicalanalysis	Sometimes	Sometimes	Always	Always
4. Inherently provides accurate historical information	No	No	Yes	Yes
5. Gene flow among species	Rarely, if ever	Not directly	Sometimes	Acceptable
6. Reproductively isolated populations recognized as separate species	Always	Always	Always	Always
7. Extensively hybridizing, diagnosably distinct populations important for establishing species status	Rarely	Rarely	Almost always	Yes, if integrities of the 2 gene pools are protected
8. ‘‘Potential’’ interbreeding of allopatric populations important for establishing species status	Yes	Yes, estimated by morphological divergence	Never	Yes, estimated from genetic distance of nuclear and mitochondrial DNA
9. Delimitation of areas of endemism	Coarse, less precise	Coarse, less precise	Fine, more precise	Fine, more precise
10. Inter-and intraspecific genetic biodiversity documented	Sometimes	Rarely	Sometimes	Always, with adequate sampling
11. Estimate of time of origin	No	Sometimes, if fossils available	Sometimes	Always
12. Provides foundation for Barcode Initiative	No	Yes, through voucher specimens/binomial names	Sometimes	Always
13. Resolves geographic limits for cryptic species	No	No	Sometimes, if gene trees are used	Always, with adequate sampling
14. Can be influenced by local environmental conditions	Yes, if morphology database used	Yes	Yes, if morphologic database used	No