Chronogenus delimitation

"…we found that no matter the divergence threshold selected, significant changes would result (lumping or splitting of genera). Therefore, at this time we opt to emphasize nomenclatorial stability by continuing to recognize at the genus level many lineages that are not of similar age" (JV Remsen et al., 2016, p.288)


Temporal thresholds (cutoffs)

Based on the study of Jetz et al. (2014), Holt & Jønsson (2014) established a “least disruptive” cutoff of 11.4 Ma for avian genera. This value is very close to the 11.79 Ma genus cutoff established for Corvides (Passeriformes) by Jønsson et al. (2016).

On the other hand, the “least-disruptive” genus cutoff for Tyranni is less than 10 Ma (as estimated from the timetree provided by Harvey et al., 2020). This time interval is also closer to the 7-8 Ma, which was chosen as a genus cutoff in Leiotrichidae (Cibois et al., 2018).

The published avian cutoffs prompted me to favour an intermediate avian genus cutoff at 10 Ma. Since a strict application of the proposed genus cutoff would result in considerable disruption of existing genus circumscriptions, it seems advisable to introduce a genus cutoff tolerance that allows to retain traditional genera as long as they are between 8 Ma and 12 Ma.

References

Cibois A, Gelang M, Alström P, Pasquet E, Fjeldså J, Ericson PGP, and Olsson U (2018), Comprehensive phylogeny of the laughingthrushes and allies (Aves, Leiotrichidae) and a proposal for a revised taxonomy, Zool. Scr. 47, 428-440. (pdf) 

Garg KM, Yin Gwee C, Chattopadhyay B, Ng NS, Prawiradilaga DM, David G, Fuchs J, Le Manh H, Martinez J, Olsson U, Tan Tu V, Chhin S, Alström P, Lei F, and Rheindt FE (2024), When colors mislead: genomics and bioacoustics of prompt re-classification of Asian flycatcher radiation (Aves: Niltavinae), Mol. Phylogenet. Evol. . e:107999. (abstract)

Harvey MG, Bravo GA, Claramunt S, Cuervo AM, Derryberry GE, Battilana J, Seeholzer GF, McKay JS, O’Meara BC, Faircloth BC, Edwards SV, Peréz-Emán J, Moyle RG, Sheldon FH, Aleixo A, Smith BT, Chesser RT, Silveira LF, Cracraft J, Brumfield RT, and Derryberry EP (2020), The evolution of a tropical biodiversity hotspot, Science 370, 1343-48. (abstract) (hi-res tree)

Holt BG, and Jønsson KA (2014), Reconciling hierarchical taxonomy with molecular phylogenies, Syst. Biol. 63, 1010-17. (free pdf)

Hosner PA, Braun EL, and Kimball RT (2016), Rapid and recent diversification of curassows, guans, and chachalacas (Galliformes: Cracidae) out of Mesoamerica: phylogeny inferred from mitochondrial, intron, and ultraconserved element sequences, Mol. Phylogenet. Evol. 102, 320-330. (abstract)

Jetz W, Thomas GH, Joy JB, Hartmann K, and Mooers AO (2012), The global diversity of birds in space and time, Nature 491, 444-448. (abstract) 

Johansson US, Nylinder S, Ohlson JI, and Tietze DT (2018), Reconstruction of the Late Miocene biogeographical history of tits and chickadees (Aves: Passeriformes: Paridae): a comparison between discrete area analyses and probabilistic diffusion approach, J. Biogeogr. 45, 14-25. (abstract)

Jønsson KA, Fabre PH, Kennedy JD, Holt BG, Borregaard MK, Rahbek C, and Fjeldså J (2016), A supermatrix phylogeny of corvoid passerine birds (Aves: Corvides), Mol. Phylogenet. Evol. 94, 87-94. (abstract)

Ohlson JI,Irestedt M, Batalha Filho H, Ericson PGP, and Fjeldså J (2020), A revised classification of the fluvicoline tyrant flycatchers (Passeriformes, Tyrannidae, Fluvicolinae), Zootaxa 4747, 167-176. (pdf)

Oliveros CH, Andersen MJ, Hosner PA, Mauck WM, Sheldon FH, Cracraft J, and Moyle RG (2019), Rapid Laurasian diversification of a pantropical bird family during the Oligocene-Miocene transition, Ibis 162, 137-152. (abstract)

Price TD, Hooper DM, Buchanan CD, Johansson US, Tietze DT, Alström P, Olsson U, Ghosh-Harihar M, Ishtiaq F, Gupta SK, Martens J, Harr B, Singh P, and Mohan D (2014), Niche filling slows the diversification of Himalayan songbirds, Nature 509, 222-225. (abstract)

Provost KL, Joseph L, and Smith B T (2018), Resolving a phylogenetic hypothesis for parrots: implications from systematics to conservation, Emu 118, 7-21. (pdf)

Reeve AH, Blom MPK, Marki PZ, Batista R, Olsson U, Edmark VN, Irestedt M, and Jønsson KA (2022) The Sulawesi Thrush (Cataponera turdoides; Aves: Passeriformes) belongs to the genus TurdusZool. Scr. 51, 32-40. (free reading)

Remsen JV, Powell AFLA, Schodde R, Barker FK, and Lanyon SM (2016), A revised classification of the Icteridae (Aves) based on DNA sequence data, Zootaxa 4093, 285-292. (abstract)