AASAGACITY.NET
  Knowledge is Empowering
A scoring system to define a species; an evaluation of a taxon/some taxa, using the Sensible Species Definition. 5 points between taxa makes a different species.



Geographic separation/Chance
of cross-breeding
Physical differences Voice

Song/Calls

Habitat preference
Behaviour
including
migration
Known
genetic differences

Total Points
sp
or
subsp

Scoring 0-1-2-3 0-1-2-3 0-1-2-3 0-2-3-4 0-1-2-3 0-2-4-5

A SENSIBLE SPECIES DEFINITION (Anderson 1998 and 2012)
Species are populations that are interbreeding and which are reproductively isolated from other such populations by their reproductive isolating mechanisms.
These may include -
     geographic separation / chance of cross-breeding;
    morphological and plumage differences;
    voice;
    habitat preference;
    behavioural differences such as nest-building, social grouping or migration;
    consistent DNA differences.
Each mechanisms can be weighted according to the strength of difference from a recognised species and given a score between 0 and 5; a total of 5 would give the taxon species status.
0





1






2





3






4





5




Broad hybrid zone





e.g. Narrow and stable hybrid zone,
or good chance of interbreeding.



e.g A small chance of interbreeding.



No chance of interbreeding, or successful breeding is not known to occur where there is breeding overlap.

Feather tracts and/or bare parts a little different,


Feather tracts and/or bare parts noticeably different,


Feather tracts and/or bare
parts very different.

Feather tracts and/or bare
parts completely different.
Not so different voice range and/or song phrases.




Noticeably different voice range and/or song phrases,






Completely different voice range and/or song phrases.
Similar or slightly different habitat preferences.



Noticeably different habitats.







Completely different habitats.
Slightly different behaviour.






Noticeably different behaviour.






Very different behaviour.
Genetic differences are barely measurable.


Genetic differences are measurable.




Genetic differences are larger.



Genetic differences are large enough to probably have non-viable offspring.



Genetic differences are so great that viable inter-breeding would be impossible.




Isolated North Australian spp
Comparison of a Universally Accepted Species with Other Taxon such as a Subspecies
 Geographic separation/Chance
of cross-breeding

Physical differences
Voice

Song/Calls

Habitat preference

Behaviour
differences

Genetic differences

Total Points
sp
or
subsp
Research -
Cormobates l. leucophaeus   
White-throated Treecreeper
Cormobates l. intermedius     White-throated Treecreeper
Cormobates l. minor               Little Treecreeper
Conclusions -
Were it not for intermedius, minor would have a geographical score of 3; but it would still need a substantial genetic divergence score (i.e. to show isolation by say a million years) to be a separate species. 

Research -

Heteromyias a. albispecularis    Ashy Robin - PNG
Heteromyias a. cinereifrons   Grey-headed Robin - NE Australia
Conclusions -
Clearly, these evolved together (there are 5 subspecies in PNG alone), and have not been separated by the Torres Strait long enough to be reproductively isolated so as to form a species. Genetic divergence studies should confirm that.

Research -
Meliphaga a. albilineata    White-lined Honeyeater - Kakadu
Meliphaga a. fordiana    Kimberley Honeyeater
Meliphaga reticulata    Streak-breasted Honeyeater - L.Sundas
Conclusions -
BLI says that "The authors who split (fordiana from albilineata) base their treatment on genetic differences between the two taxa; Birdlife Taxonomic Working Group adopts the view of Edwards et al. (2005) that intrageneric genetic differentiation alone is an unsatisfactory basis for species recognition."
Here, despite recognition of a mild genetic differentiation and points also given for geographical separation and some little physical differences, fordiana still fails to come up to species level.   

Research -
Lichenostomus v. versicolor    Varied Honeyeater
Lichenostomus v. fasciogularis   Mangrove Honeyeater
Lichenostomus v. sonoroides   Varied Honeyeater
Lichenostomus v. intermedius   Varied Honeyeater
Lichenostomus v. vulgaris   Varied Honeyeater
Conclusions -
It was always unlikely that of the 5 subspecies of Varied Honeyeater which are found interbreeding all around coastal PNG and along the NE coast of Australia that only one was going to be a different species; this Australian taxon was the only subspecies considered, which is very poor science and typical of the blinkered approach many Australian ornithologists have toward Australasian species; related taxa in PNG are often ignored.
But even had all 5 subspecies been considered none should have made it to species level.



0
2
2







0
2-3







0
2
3












0
0-1
0-1
0-1
0-1

0
0
1







0
0-1







0
1
2












0
1
1
1
1

0
0
0







0
0







0
0
1-2












0
0
0
0
0

0
0
0







0
0







0
0
1-2












0
0
0
0
0

0
0
0







0
0







0
0
0












0
0
0
0
0

0
0
0







0
0







0
1
0












0
0
0
0
0

0
2
3







0
2-4







0
4
7-9












0
1-2
1-2
1-2
1-2

sp
subsp
subsp







sp

subsp







sp
subsp
sp












sp
subsp
subsp
subsp
subsp