Species delimitation (1 Viewer)

[Richard Klim]

Gill 2014

Frank kindly invited me to comment on a draft of his very topical and thought-provoking article, but I certainly can't claim to have made any significant contribution! Hopefully it'll be more widely accessible somewhere before too long...

 

[aegithalos]

Gill 2014. Species taxonomy of birds: Which null hypothesis? Auk 131(2): 150–161. [abstract]

Thanks, it's an interesting one. That the polytypic species concept reduced the number of bird species from ca 19,000 to ca 9,000 (now 10,000) was one of Mayr's proud boasts. This proposal will push it back up. Along with the revolution in bird taxonomy through molecular phylogenetics (as we learned yesterday, there are still new families out there), we clearly still are a long way from stability in understanding bird biodiversity. And if we don't know how bird species there are to within a factor of two, how little do we know of other groups?

I look forward to seeing how this pans out - and I will continue to keep my own observation records at subspecies level as far as I can. We live in interesting times!

Keith

 

[jurek]

Note, that current ranges of most sedentary birds are fragmented due to human activity and chances of hybridization are nil.

In result, this proposal will push the number of bird species much higher than 19,000.

And paradoxically, as bird populations become more fragmented and inbred, the number of species will grow. This may put more interest on these remains of genetic diversity, but the number of bird species will quickly become unmanageable.

 

[Kirk Roth]

Note, that current ranges of most sedentary birds are fragmented due to human activity and chances of hybridization are nil.

In result, this proposal will push the number of bird species much higher than 19,000.

And paradoxically, as bird populations become more fragmented and inbred, the number of species will grow. This may put more interest on these remains of genetic diversity, but the number of bird species will quickly become unmanageable.

But realistically, I don't foresee any of the major taxonomic committees pushing the number of species to a level that they, themselves, cannot manage. And at the current state of debate regarding species concepts, I think it would literally be centuries before people are being taken seriously splitting every population of Prairie-chicken, House Sparrow, and so on. We haven't even split Great Danes from Yorkies yet - there is a long way to go in the field of "anthropogenic speciation."

 

[Mysticete]

Indeed, in practice I can't think of any taxonomist who would argue that because X species has a fragmented range, it means that every little fragment is a new species. Selection of appropriate genetic markers in phylogenetic analysis should remove the influence of historical range fragmentation

 

[jurek]

Note, that most scientists study only a minority of species and don't have overview of the rest.

What you suggest is that first people who propose splits of their 'favorite' species (say, people studying amazon parrots in C America, or European twitchers) will have their split accepted. Later taxonomic commitees realize there is too many species and stop illogically - races of some species were split, other species with comparable differences are not split.

I foresee twofold scenario.

Either: taxonomy will become disassociated from birding and conservation. This is happening now with higher level taxa, will happen with species.

Or: repeat of Mayr. Field biologists remember the practical reasons of more inclusive species definition: too many, too similar, large hybrid populations. And the Second Mayr proposes big lumping, to the relief of all.

 

[jurek]

Indeed, in practice I can't think of any taxonomist who would argue that because X species has a fragmented range, it means that every little fragment is a new species. Selection of appropriate genetic markers in phylogenetic analysis should remove the influence of historical range fragmentation

Read eg. the paper proposing split of giraffes into 6 species. Races which had continous range until 50 years go and are genetically nested within other races are proposed to be species.

 

[Mysticete]

Those races have distinctive coat patterns, size differences, and other morphological differences prior to any historic fragmentation, and may have had relatively minor or limited gene flow between populations.

 

[Richard Klim]

Torstrom et al

Torstrom, Pangle & Swanson (in press). Shedding Subspecies: the influence of genetics on reptile subspecies taxonomy. Mol Phylogenet Evol. [abstract]

(Not birds, but the same issues...)

 

[Mysticete]

Strikes me that any attempt to establish a "standard" between subspecies and species (especially in herps, which are hard to apply the BSC to) is going to be fraught with failure.

 

[Richard Klim]

Collar 2013 pdf

Collar 2013. The Bernard Tucker Memorial Lecture: A species is whatever I say it is. British Birds 106(3): 130–142. [abstract]

[pdf]

 

[Richard Klim]

Gill 2014

Gill 2014. Species taxonomy of birds: Which null hypothesis? Auk 131(2): 150–161. [abstract]

Now open access. [pdf]

Toews 2015. Biological species and taxonomic species: Will a new null hypothesis help? (A comment on Gill 2014). Auk 132(1): 78–81. [abstract]

 

[Richard Klim]

Toews 2015 pdf

Toews 2015. Biological species and taxonomic species: Will a new null hypothesis help? (A comment on Gill 2014). Auk 132(1): 78–81. [abstract]

[pdf]

 

[Richard Klim]

Pante et al

Pante, Schoelinck & Puillandre (in press). From integrative taxonomy to species description: one step beyond. Syst Biol. [abstract] [pdf]

PS. Not directly related, but recently posted elsewhere on this forum...

Magee, May & Moore 2014. The dawn of open access to phylogenetic data. PLoS ONE 9(10): e110268. [article] [pdf]

 

[Richard Klim]

Péron & Altwegg

Possibly of related interest...

Péron & Altwegg (in press). The abundant centre syndrome and species distributions: insights from closely related species pairs in southern Africa. Global Ecol Biogeogr. [abstract] [supp info]

(supp info identifies species studied.)

 

[Richard Klim]

Genera

Slightly off-topic (next rank)...

Strand & Panova (in press). Size of genera – biology or taxonomy? Zool Scr. [preview]

 

[Richard Klim]

Zachos

Zachos (in press). Taxonomic inflation, the Phylogenetic Species Concept and lineages in the Tree of Life – a cautionary comment on species splitting. J Zool Syst Evol Res. [abstract]

 

[Richard Klim]

Pigot & Tobias 2015

Pigot & Tobias 2015. Dispersal and the transition to sympatry in vertebrates. Proc R Soc B 282(1799). [abstract] [datasets]

 

[Mysticete]

Zachos (in press). Taxonomic inflation, the Phylogenetic Species Concept and lineages in the Tree of Life – a cautionary comment on species splitting. J Zool Syst Evol Res. [abstract]

Wow that is a pretty horrible abstract. They literally just have some pictures of mammals, and just say "these were all split because of PSC, which is bad"

 

[l_raty]

Wow that is a pretty horrible abstract. They literally just have some pictures of mammals, and just say "these were all split because of PSC, which is bad"

I haven't read it but, even if it's called one, what you see there is not, actually, "an abstract". You can see a [preview here]: the paper is a Letter to the Editor and it has no abstract at all...
So the author may well not be the one to blame.