• BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

    Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Sporophila (1 Viewer)

l_raty

laurent raty
Campagna, Repenning, Silveira, Fontana, Tubaro, Lovette. [2016.] Repeated divergent selection on pigmentation genes in a rapid finch radiation driven by sexual selection.
[preprint on BioRχiv]
 

Peter Kovalik

Well-known member
Slovakia
Sporophila torqueola

Mason NA, Olvera-Vital A, Lovette IJ, Navarro-Sigüenza AG. Hidden endemism, deep polyphyly, and repeated dispersal across the Isthmus of Tehuantepec: Diversification of the White-collared Seedeater complex (Thraupidae: Sporophila torqueola). Ecol Evol. 2018;00:1–15. https://doi.org/10.1002/ece3.3799

Abstract:

Phenotypic and genetic variation are present in all species, but lineages differ in how variation is partitioned among populations. Examining phenotypic clustering and genetic structure within a phylogeographic framework can clarify which biological processes have contributed to extant biodiversity in a given lineage. Here, we investigate genetic and phenotypic variation among populations and subspecies within a Neotropical songbird complex, the White-collared Seedeater (Sporophila torqueola) of Central America and Mexico. We combine measurements of morphology and plumage patterning with thousands of nuclear loci derived from ultraconserved elements (UCEs) and mitochondrial DNA to evaluate population differentiation. We find deep levels of molecular divergence between two S. torqueola lineages that are phenotypically diagnosable: One corresponds to S. t. torqueola along the Pacific coast of Mexico, and the other includes S. t. morelleti and S. t. sharpei from the Gulf Coast of Mexico and Central America. Surprisingly, these two lineages are strongly differentiated in both nuclear and mitochondrial markers, and each is more closely related to other Sporophila species than to one another. We infer low levels of gene flow between these two groups based on demographic models, suggesting multiple independent evolutionary lineages within S. torqueola have been obscured by coarse-scale similarity in plumage patterning. These findings improve our understanding of the biogeographic history of this lineage, which includes multiple dispersal events out of South America and across the Isthmus of Tehuantepec into Mesoamerica. Finally, the phenotypic and genetic distinctiveness of the range-restricted S. t. torqueola highlights the Pacific Coast of Mexico as an important region of endemism and conservation priority.

[pdf]
 

Melanie

Well-known member
Sporophila maximiliani

Taxonomy, natural history, and conservation of the Great-billed Seed-Finch Sporophila maximiliani (Cabanis, 1851) (Thraupidae, Sporophilinae)
FLÁVIO KULAIF UBAID, LUÍS FABIO SILVEIRA, CESAR A. B. MEDOLAGO, THIAGO V. V. COSTA, MERCIVAL ROBERTO FRANCISCO, KARLLA V. C. BARBOSA, ADIR D. S. JÚNIOR

Abstract

Seed-finches are small-sized Neotropical granivorous birds characterized by extremely strong and thick beaks. Among these birds, the Great-billed Seed-Finch Sporophila maximiliani has been selectively and intensively trapped to the extent that has become one of the most endangered bird species in South America, yet its taxonomy remains complex and controversial. Two subspecies have been recognized: S. m. maximiliani (Cabanis, 1851), mainly from the Cerrado of central South America, and S. m. parkesi Olson (= Oryzoborus m. magnirostris), from northeastern South America. Originally, S. m. parkesi was diagnosed as being larger than the Large-billed Seed-Finch, S. c. crassirostris (Gmelin, 1789), but proper comparisons with S. m. maximiliani, which is larger than S. c. crassirostris, were never performed. Here we provide a review of the taxonomic and nomenclatural history of S. maximiliani, reevaluate the validity and taxonomic status of the subspecies based on morphological characters, and significantly revise its geographic distribution. Analyses based on plumage patterns and a Principal Component Analysis of morphometric characters indicated that S. m. parkesi is most appropriately treated as a synonym of the nominate taxon, which results in a monotypic S. maximiliani comprising two disjunct populations. Further, we conducted systematic searches for S. maximiliani in Brazil, in an attempt to obtain natural history information. After more than 6,000 hours of fieldwork in 45 areas of potential and historical occurrence, S. maximiliani was located only in two sites, in marshy environments called veredas, confirming the critical conservation status of this species, at least in Brazil. We discuss the conservation potential for, and the problems involved with, captive breeding of S. maximiliani for reintroduction into the wild.

http://www.mapress.com/j/zt/article/view/zootaxa.4442.4.4
 

Peter Kovalik

Well-known member
Slovakia
Sporophila torqueola

TiF Update August 2:

The White-collared Seedeater, Sporophila torqueola has been split into Morellet's Seedeater / White-collared Seedeater, Sporophila morelleti and and Cinnamon-rumped Seedeater, Sporophila torqueola based on the AOS 59th Supplement and Mason et al. (2018). As with the Juncos above, they are not sister taxa.
 

mb1848

Well-known member
He is back!
Note from 59th AOS Supplement.
Notes.—The scientific name honors the collector of the
type specimen, P. M. A. Morelet (Salvin and Godman
1885), but Bonaparte misspelled his name in the species
description, an error perpetuated in the English name
‘‘Morellet’s Seedeater’’ by AOU (1886), Ridgway (1901), and
others.
Pendantcy is a sickness.
 
Last edited:

Peter Kovalik

Well-known member
Slovakia
Hussein A. Hejase, Ayelet Salman-Minkov, Leonardo Campagna, Melissa J. Hubisz, Irby J. Lovette, Ilan Gronau, and Adam Siepel. Genomic islands of differentiation in a rapid avian radiation have been driven by recent selective sweeps. PNAS first published November 16, 2020; https://doi.org/10.1073/pnas.2015987117

Abstract:

Numerous studies of emerging species have identified genomic “islands” of elevated differentiation against a background of relative homogeneity. The causes of these islands remain unclear, however, with some signs pointing toward “speciation genes” that locally restrict gene flow and others suggesting selective sweeps that have occurred within nascent species after speciation. Here, we examine this question through the lens of genome sequence data for five species of southern capuchino seedeaters, finch-like birds from South America that have undergone a species radiation during the last ∼50,000 generations. By applying newly developed statistical methods for ancestral recombination graph inference and machine-learning methods for the prediction of selective sweeps, we show that previously identified islands of differentiation in these birds appear to be generally associated with relatively recent, species-specific selective sweeps, most of which are predicted to be soft sweeps acting on standing genetic variation. Many of these sweeps coincide with genes associated with melanin-based variation in plumage, suggesting a prominent role for sexual selection. At the same time, a few loci also exhibit indications of possible selection against gene flow. These observations shed light on the complex manner in which natural selection shapes genome sequences during speciation.
 

Users who are viewing this thread

Top