DOI: 10.3897/vz.76.e182505

Authors: Gerald Mayr

Abstract: Abstract A diverse array of early Eocene zygodactyl birds has been assigned to the Psittacopasseres, the clade including parrots and passerines, but the exact affinities of the fossils are controversially resolved. Here, new analyses are performed based on a revised character matrix. Concerning critical taxa, the results of the primary analysis and that of the analyses constrained to a molecular backbone phylogeny show disparate tree topologies, and probably none correctly reflects the true interrelationships of the fossil taxa. The new taxon Psittacomimidae fam. nov. is introduced for a clade formed by the taxa Psittacomimus and Parapsittacopes, which were before assigned to the Psittacopedidae. The Psittacomimidae fam. nov. are likely to be the sister taxon of the Parapasseres, that is, the clade formed by the Zygodactylidae and Passeriformes, with the Morsoravidae branching next. A clade formed by all or most Halcyornithidae and the Messelasturidae is termed Messelasturiformes. A derived morphology of the proximal tarsometatarsus is reported, which may support a clade including the Vastanavidae and Messelasturiformes. However, although psittacopasserine affinities of the Vastanavidae conform to the overall osteology of these birds, the higher-level affinities of the Messelasturiformes are more elusive.

HTML

XML

PDF

DOI: 10.3897/vz.76.e171834

Authors: Vagner Cavarzere, Enrico L. Breviglieri, Luís F. Silveira

Abstract: The genus Cercomacra includes six species, among them C. cinerascens, which is widespread throughout the Amazon Basin. Historically, six names have been proposed for this species complex, but only four are currently recognized. Past studies have explored relationships among Cercomacra species using either morphological or molecular data, with taxonomic assessments mainly conducted in the early 20th century. To reevaluate the validity of the currently accepted C. cinerascens taxa, we performed a comprehensive taxonomic revision that combined traditional morphological and vocal analyses. Additionally, we used BirdNET, a pre-trained deep learning algorithm developed for bird sound classification. We examined 682 specimens and 347 recordings and identified two distinct morphotypes distributed north and south of the Amazon Basin, along with four recognizable loudsong types. Using both morphological and vocal features, we identified five distinct lineages, two of which are newly described and named. Cercomacra cinerascens occurs north of the Pastaza and Amazon Rivers in northern Amazonia; C. sclateri is found in eastern Ecuador and Peru, south of the Pastaza River and east of the Andes, east to the Ucayali River; and C. iterata stat. nov. is located east of the Tapajos River. The two newly described species are found south of the Amazon and Marañon Rivers. Cercomacra mura sp. nov. occupies the Ucayali-Madeira interfluve, and Cercomacra raucisona sp. nov. inhabits the Madeira-Tapajos interfluve.

HTML

XML

PDF

DOI: 10.3897/vz.76.e173317

Authors: Sebastián Lyons, Sergio D. Rosset, Mariana Picasso, Carolina Acosta Hospitaleche

Abstract: Woodpeckers possess specialised cranial and cervical skeletal adaptations that enable them to excavate wood, yet how these structures form and integrate during development is still largely unknown. While several cranial skeletal traits have been described in this context, their postnatal development has received little attention. This study examines the postnatal skeletal development of four species, from nestlings to juveniles, using cleared and stained specimens to assess ossification and bone fusion. Woodpeckers show delayed cranial and cervical skeletal ossification typical of altricial birds, with many elements remaining cartilaginous in the first post-hatching days. Lineage-specific features—including the dorsal process of the pterygoid and the rostral process of the paroccipital process—ossify later. The rostral process originates in the exoccipital, with minor contribution from the squamosal, supporting its reinterpretation as processus rostralis paroccipitalis (new term). The lacrimal is consistently absent, indicating a true secondary loss probably linked to cranial kinesis. The mesethmoid may contribute to the frontal overhang in species where present. The epiotic forms part of the external cranial vault, also reported in other birds, suggesting it is more widespread than previously assumed. Cervical vertebrae, in turn, follow the altricial pattern, with late ossification of the atlas and unfused neural arches at early stages, showing considerable heterogeneity among altricial birds. Collectively, these findings show how postnatal skeletal development integrates functional, mechanical, and evolutionary constraints, offering new insights into the ontogeny and specialisation of the woodpecker skull and neck.

HTML

XML

PDF

DOI: 10.3897/vz.75.e167908

Authors: Irina V. Kulikova, Philip Lavretsky, Kevin G. McCracken, Yury N. Zhuravlev, Irina L. Miroshnichenko, Andrew B. Correll, Jeffrey L. Peters

Abstract: Eurasian wigeon (Mareca penelope) and American wigeon (Mareca americana) are sister species with diagnosable differences mostly in male plumage. They breed in the Palearctic and Nearctic, respectively, but due to transoceanic migrations come in contact in North America, Western Europe, and north-eastern Asia, where they occasionally hybridize. To estimate genomic divergence and study their population structure we sequenced mitochondrial (mt) DNA control region and obtained 3092 autosomal and 189 Z chromosome loci from double-digest restriction associated DNA sequencing (ddRAD-seq). Consistent with previous work with few nuclear loci, we observed discordant patterns between mtDNA and nuclear DNA divergence. Deeply divergent species-specific mtDNA haplogroups contrasted with low autosomal differentiation and moderate Z-sex chromosome divergence. Meanwhile, Z-linked differentiation (ФST = 0.192) between taxa was five times higher than differentiation of autosomal loci (ФST = 0.0386), with four fixed and eight nearly fixed differences in SNPs discovered in three and six Z-linked outlier loci, respectively. No species-specific SNP variants were found among 83 autosomal outlier loci. This elevated Z-chromosome differentiation is most likely the result of selection that has been important in speciation. The lack of population genetic structure within Eurasian wigeon and American wigeon supports the common notion that migratory waterfowl have high dispersal ability that contributes to strong genetic connectivity between geographic populations.

HTML

XML

PDF

DOI: 10.3897/vz.74.e122418

Authors: Jason R. Ali, Uwe Fritz

Abstract: Abstract Our focus is the colonization history of the Galápagos’ vertebrate clades: 11 land-bound groups (eight reptiles, three rodents) and 13 taxa of flyers and swimmers (ten winged birds, two pinnipeds, one penguin). Using ‘colonization intervals’ and ‘colonization profiles’, it is clear that the two sets of taxa assembled very differently. The former includes older clades with between one, and potentially eight, predating the emergence of the oldest island (4 Mya). For the origin of some lineages, now-sunken landmasses associated with the Galápagos mantle-plume hotspot must have been involved, but for others it could reflect taxonomic uncertainties. In contrast, the taxa of flyers and swimmers are markedly younger, indicating either higher rates of colonization and extirpation for these sorts of animal, or continued genetic influx from mainland populations, or some combination of both factors. Concerning the first, possible drivers are the environmental stressors associated with the El Niño–La Niña climate system; the recent clades may be vulnerable to extreme events within the oscillation sequence, perhaps on ≥104-year timescales. Therefore, loose temporal thresholds might exist for the archipelago’s vertebrate groups beyond which selection fortifies them from the most challenging of seasonal states. Moreover, in a world of climate uncertainty, the findings appear relevant to conservation initiatives suggesting a focusing on the younger elements within the Galápagos’ biota.

HTML

XML

PDF

DOI: 10.3897/vz.74.e112446

Authors: Vagner Cavarzere, Luís F. Silveira

Abstract: Abstract Cercomacroides serva is widely distributed in northern South America. However, this species has never been thoroughly evaluated taxonomically. We conducted a taxonomic study of three taxa currently classified under Cercomacroides serva, based on a study of 307 skins and 145 recordings of male loudsongs. Females from the northwest Amazonian population differ qualitatively from populations from the southwest Amazon in the coloration of the upperparts, primary, and tail. Male loudsongs are superficially similar between these two populations, but the shape of the notes differs significantly. There is no evidence of intergradation or clinal variation in female plumage or male loudsongs. Based on differences in plumage coloration, loudsongs, and lack of evidence of intergradation, we suggest that two species are best recognized. The name Cercomacroides serva is here restricted to populations north of the Marañon River in Peru, to the north in Ecuador, and in southwestern Colombia. The name Cercomacroides hypomelaena comb. nov. is revived. This species is found south of the Marañon River, and on both banks of the Ucayali River in Peru, to the eastern left bank of the Madeira River in Brazil, and in northern Bolivia.

HTML

XML

PDF

DOI: 10.3897/vz.74.e114112

Authors: M. Alejandra Sosa, Carolina Acosta Hospitaleche

Abstract: Abstract The vertebral column in tetrapods consists of several constant regions, namely the cervical, thoracic, lumbar, sacral, and caudal regions. Each of these regions is characterized by a specific number of vertebrae, contributing to the overall vertebral formula. Supernumerary and/or missing vertebrae have only been sporadically mentioned for penguins, and the specific vertebral formula is only determined for some non-passeres orders. Variations in the anatomy and vertebral number of South American and Antarctic penguin species are evaluated here. Sixty-six specimens of Aptenodytes forsteri, Pygoscelis adeliae, P. antarcticus, P. papua, Spheniscus magellanicus, and Eudyptes chrysocome were examined to establish the vertebral formula for six South American and Antarctic species, reporting the type and frequency of the variations found in the generalized configuration. We found no intraspecific variation in respect of the number of cervical as well as cervicothoracic vertebrae in all penguin species studied. Intra- and interspecific variation occur in the thoracic, synsacral, and caudal regions comprising 6–7, 13–14 and 5–8 vertebrae, respectively. Particularly, the variations were found in the transitional zones between one region and another and/or between synsacral segments.

HTML

XML

PDF

DOI: 10.3897/vz.72.e85419

Authors: George Sangster

Abstract: The taxonomic status of the North American and Eurasian populations of northern goshawk A. gentilis has been called into question by recent molecular studies, indicating the need for additional taxonomic study. Vocalisations have long played an important role in diagnosing potentially reproductively isolated groups of birds. The chattering-type call of A. gentilis plays a role in advertisement and pair-contact, making this a suitable basis for taxonomic study of vocalisations. The data set consisted of recordings of the calls of 75 individuals of the Eurasian gentilis-group of A. gentilis, 37 of the North American atricapillus-group of A. gentilis and, for comparison, seven of Henst’s goshawk A. henstii. The three groups showed non-overlapping variation in the duration of call-notes and also showed several other highly significant differences. Discriminant Function Analysis resulted in 100% correct classification of recordings into the three groups. It is here argued that the new bioacoustic data, in combination with previous evidence of morphological, mitochondrial DNA and genomic DNA differences between Eurasian and North American A. gentilis, suggests that two species are best recognised: northern goshawk A. gentilis and American goshawk A. atricapillus. A. gentilis / A. atricapillus add to a growing list of Holarctic temperate zone taxa that have recently been recognised as separate species based on a deep phylogeographic split between Eurasian and North American populations in combination with differences in other characters. This is the first quantitative taxonomic study of vocalisations in Accipitridae.

HTML

XML

PDF

DOI: 10.3897/vz.71.e71268

Authors: Gerald Mayr

Abstract: Abstract The occurrence of lateral openings and pleurocoels (lateral fossae) in the corpus of the thoracic vertebrae of extant and fossil neornithine birds is reviewed, with both features having been identified as osteological correlates of the avian pulmonary system. Openings mainly occur in larger species with a high overall bone pneumatization but do not seem to serve for the passage of lung or air sac diverticula. Pleurocoels, on the other hand, are not directly related to pneumatic features and constitute a plesiomorphic trait that was widespread in Mesozoic non-neornithine birds. It is noted that an inverse correlation exists between the occurrence of pleurocoels and the pneumatization of the humerus, with pleurocoels being mainly found in extant and fossil taxa, in which the humerus is not pneumatized by diverticula of the clavicular air sac. Here it is hypothesized that pleurocoels primarily serve to increase the structural resistance of the vertebral body and were reduced multiple times in neornithine birds. In some taxa, their reduction may be related to the development of the furcula, which assists ventilation of the clavicular and cervical air sacs and may thereby contribute to the pneumatization of both, the humerus and the thoracic vertebrae. If so, Mesozoic non-neornithine birds, which had a rigid furcula with massive shafts as well as non-pneumatic humeri and pronounced pleurocoels, are likely to have differed in functional aspects of their air sac system from extant birds.

HTML

XML

PDF

DOI: 10.3897/vz.71.e67501

Authors: George Sangster, Guy M. Kirwan, Jérôme Fuchs, Edward C. Dickinson, Andy Elliott, Steven M. S. Gregory

Abstract: Abstract Multiple molecular phylogenetic studies have demonstrated that two Neotropical raptors, tiny hawk Accipiter superciliosus and its sister species semicollared hawk A. collaris, are not closely related to core Accipiter, and that A. superciliosus, at least, possesses osteological characters not replicated in the remainder of the genus. Based on these data, there is a need to recognise their distinctiveness at generic level. However, as recently noted in two global bird checklists, no name is available to accommodate them, so we provide a new nomen here. Furthermore, two Asian accipitrids, crested goshawk A. trivirgatus and its presumed closest relative Sulawesi goshawk A. griseiceps, are also phylogenetically distinctive; in this case the genus-group name Lophospiza is applicable. We also designate type species for two genus-group names (Hieraspiza and Eusparvius) currently in the synonymy of Accipiter, and, as an aid to future workers, we provide a synonymy of the genus Accipiter and a list of species currently included in Accipiter for which published molecular phylogenetic data are apparently lacking.

HTML

XML

PDF

DOI: 10.3897/vz.71.e65952

Authors: Martin Päckert, Jens Hering, Abdelkrim Ait Belkacem, Yue-Hua Sun, Sabine Hille, Davaa Lkhagvasuren, Safiqul Islam, Jochen Martens

Abstract: Abstract The Old World sparrows include some of the best-studied passerine species, such as the cosmopolitan human commensal, the house sparrow (Passer domesticus) as well as poorly studied narrow-range endemics like the Iago sparrow (P. iagoensis) from the Cape Verde Archipelago or specialists from extreme environments like the desert sparrow (P. simplex). It is therefore notable that to date the most complete phylogenetic hypothesis for the Old World sparrows comprised only ten of 43 currently accepted species. With this study we provide an updated phylogeny of Passeridae covering about two third of the family’s species richness. Though still being far from taxon-complete, this new phylogenetic hypothesis provides firm evidence to clarify some open taxonomic questions. All genus-level taxa were reciprocally monophyletic with strong support. Contrary to previous classifications, bush sparrows and rock sparrows were not sister taxa, and therefore their classification in separate genera Gymnoris and Petronia is justified. Plumage color traits like the yellow throat patch of the latter two genera or head color pattern in Passer species do not provide reliable phylogenetic information, except for the large-sized African grey-headed sparrows that resulted as a monophyletic group (P. diffusus, P. griseus, P. gongoensis). Unexpectedly, two small-sized species, P. eminibey and P. luteus that to date are regarded as close relatives were firmly nested in two separate clades of Passer sparrows. Therefore, their separate generic treatment under Sorella eminibey and Auripasser luteus (together with A. euchlorus) does not seem justified.

HTML

XML

PDF

DOI: 10.3897/vz.71.e61728

Authors: George Sangster, Gerald Mayr

Abstract: Recent genomic data sets have resolved many aspects of higher-level phylogenetic relationships of birds. Eleven phylogenomic studies provide congruent support for a clade formed by Procellariiformes, Sphenisciformes, Ciconiiformes, Suliformes and Pelecaniformes. This clade is here named ‘Feraequornithes’ following the rules and requirements of the PhyloCode.

HTML

XML

PDF

DOI: 10.3897/vz.68.e176207

Authors: Mariana Beatriz Julieta Picasso, María Clelia Mosto

Abstract: Caracaras (Aves, Falconiformes, Falconidae) are Neotropical diurnal raptors that belong to the subfamily Polyborinae. The forelimb myology of this group has not been comprehensively studied or compared with that of other Falconidae. Thus, the aims of this study were i) to describe the forelimb muscles of two species of Polyborinae (Caracara plancus and Milvago chimango), ii) to explore the possible relationship between muscular features and their function in flight behavior and iii) to compare the muscular features of these species with those of species of the subfamily Falconinae. To this end, the forelimb muscles of C. plancus (n = 4) and M. chimango (n = 4) were dissected. Additonally, to complement this data set, two specimens of M. chimachima were dissected. The mass of each muscle of one wing and its percentage with respect to the body mass were obtained. A total of 45 muscles were identified, and differences with respect to Falconinae were related to the presence of single or additional bellies. The total forelimb muscle mass represented between 7.68 and 10.26 % of the body mass. The muscle pectoralis represented ̴ 5% of the body mass, followed by the muscles scapulohumeralis caudalis (0.64 – 0.79%), deltoideus major (0.43 – 0.53%), supracoracoideus (0.34 – 0.38%) and biceps brachii (0.26 – 0.39%). The high values of these muscles are in agreement with their important function: they are involved in the downstroke and upstroke phases of the flapping flight. On the other hand, the muscles that seemed to contribute little to the mechanical power for flight presented low values that ranged between 0.01 and 0.25%. Comparison of the forelimb muscles of caracaras with published data on Falconinae species suggests that their muscular features might be associated with their type of flight, which is more erratic and less powerful than that of Falconinae.

HTML

PDF