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Presumable phylogeny of Anseriformes: (a) Presbyy ornithidae, (b) Anhimidae, (c) Anseranatidae, (d) Anatidae, which illustrate hemiplasy in the bill structure, analogous to the modeling case. (a, c, d) show progressive structure of the jaw apparatus.
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Cladograms usually include many evolutionary reversions, parallelisms, and convergences united under the term homoplasy. Recently, it has become evident that molecular traits that look like homoplasy may be in fact true homologies. The processes of independent sorting of genes, which provide the basis of these events, were recently termed hemiplasy...
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Context 1
... presbyornithids. Taking into account the early appearance of presbyornithids in the fossil record and their surprisingly primitive osteology, it is possible to assume that, although the apomorphic structure of the jaw apparatus is homologous in this group and anatids, this does not necessarily mean sister relationn ships between the two groups (Fig. 3). In this example, the complex jaw apparatus of anatids and presbyornii thids satisfy condition 1 of character 1 of the model matrix. As the basal anseriforms Anhimidae evolved, the "anatid" jaw apparatus could have been changed with the loss of ancestral specialization for filtration feeding; this statement is supported by the presence ...
Citations
... Therefore, examination of the ecological specializations and adaptations of presbyornithids is crucial to a greater understanding of the early evolution of modern waterfowl. Numerous experts have debated the phylogenetic af-ЗООЛОГИЧЕСКИЙ ЖУРНАЛ том 97 № 8 2018 ZELENKOV, STIDHAM finities of presbyornithids with respect to the crown Anseriformes (Feduccia, 1976(Feduccia, , 1978Olson, Feduccia, 1980;Ericson, 1997;Livezey, 1997;Dyke, 2001;Mayr, 2008;Elzanowski, Stidham, 2010, 2011Zelenkov, 2011Zelenkov, , 2016Elzanowski, 2014;Worthy et al., 2016Worthy et al., , 2017Agnolin et al., 2017). Despite those in depth analyses and discussions, there is no consensus on its phylogenetic placement, and the exact position of Presbyornis and its closest relatives varies depending on the analysis [i.e., outside crown Anseriformes, as sister to Anatidae, as sister to Anatoidea (Anatidae + + Anseranatidae), and as sister to Anseranatidae]. ...
... Therefore, examination of the ecological specializations and adaptations of presbyornithids is crucial to a greater understanding of the early evolution of modern waterfowl. Numerous experts have debated the phylogenetic af-ЗООЛОГИЧЕСКИЙ ЖУРНАЛ том 97 № 8 2018 ZELENKOV, STIDHAM finities of presbyornithids with respect to the crown Anseriformes (Feduccia, 1976(Feduccia, , 1978Olson, Feduccia, 1980;Ericson, 1997;Livezey, 1997;Dyke, 2001;Mayr, 2008;Elzanowski, Stidham, 2010, 2011Zelenkov, 2011Zelenkov, , 2016Elzanowski, 2014;Worthy et al., 2016Worthy et al., , 2017Agnolin et al., 2017). Despite those in depth analyses and discussions, there is no consensus on its phylogenetic placement, and the exact position of Presbyornis and its closest relatives varies depending on the analysis [i.e., outside crown Anseriformes, as sister to Anatidae, as sister to Anatoidea (Anatidae + + Anseranatidae), and as sister to Anseranatidae]. ...
The fossil avian genus Presbyornis and its relatives (Family Presbyornithidae) are almost universally considered as one of the oldest known filter-feeding specialists among Anseriformes. Such an assumption is based almost entirely on the bill morphology which in Presbyornis is very similar to that of some modern ducks. However, the quadrate bone (key element of the kinetic apparatus of the avian skull) is different in Presbyornis as compared to that in other anseriforms, and shares plesiomorphic similarities with primitive non filter-feeding galliforms. This observation alone requires a functional explanation, as no modern (filter-feeding) anser-iforms possess such quadrate bone. Here, we analyze the structural adaptations to filter-feeding in the feeding apparatus of modern ducks, as developed mainly by the late Prof. F.Ya. Dzerzhinsky, and assess their presence in the skull of Presbyornis. We show that a duck-like bill is one of the few duck-like features in the skull of Presbyornis, and most other functional units of its feeding apparatus are similar to those of Galliformes. Most importantly, Presbyornis lacks features indicative of the presence of the ligament-based system fixing the lower jaw against a rostral and caudal displacement. Such fixation is necessary for powerful piston-like tongue movements which in modern ducks provide water inflow and expulsion during filtration. Thus, Presbyornis could not have effectively filtrated very small particles using high-frequency jaw and tongue movements (as do modern ducks) and most likely fed on larger objects which it filtered with slower jaw movements. Presby-ornis likely illustrates an important step in the evolution of Anserifomes, when these birds switched from feeding on fixed (likely underwater) to floating food items. The acquisition of specialized filter-feeding in anatids may be viewed as a gradual process initiating from a Presbyornis-like feeding apparatus. Our conclusions highlight a slow and stepwise evolution of the complex morphological traits and emphasize a mosaic nature of intermediate forms.
... The cranial morphology of Presbyornithidae is very similar to that of the mod ern ducks, so that the former are even regarded as a sis ter group of Anatidae in cladistic analysis (Ericson, 1997;Livezey, 1997). The effect of synapomorphy multiplication may account for this systematic posi tion of Presbyornithidae (Zelenkov, 2011), since virtu ally all other anatomical traits of these birds are extremely primitive. The humerus in Presbyornithidae is similar to that of primitive phoenicopteriformes and waders, trunk vertebrae have an opisthocoelous struc ture (preserved in very few birds, such as parrots), the sternum has two pairs of incisions like those of Galli formes (notably, Anseriformes have a single incision), the distal tibiotarsus is similar to those in flamingos (Fig. 2), and the tarsometatarsus is elongated, just as in long legged waders . ...
The apparent morphological lacunae dividing the macrotaxa of modern birds (orders of Neornithes) present a serious impediment to the construction of macroevolution models. However, the discovery and detailed investigation of multiple groups of fossil birds in recent decades contributed to the elucidation of the process of the formation of modern higher taxa and allowed for analysis of the macroevolution process that occurred in this group of vertebrates during the Cenozoic period. The present article is a concise review of the “transitional” taxa with a focus on representatives of the Galloanseres clade. Almost all of the transitional bird forms exhibit a mosaic morphology, although certain stable morphological traits or combinations of traits occur in different groups and may represent either a primitive or an advanced feature for a specific group. The stability of these morphological features is due to the correlation between ontogenetic processes, whereas the independent evolution of individual morphological characteristics is related to the modular organization of ontogeny. The problem of the emergence of the morphological type of modern Passeriformes is discussed with modular organization of the birds’ feet as an example. Mosaicism of the features in the transitional forms is regarded as the only macroevolutionary pathway possible, given the restraint on parallel optimization of multiple systems of the body. Consequently, stem taxa with mosaic morphology are regarded as ancestors of crown taxa. Complete filling of the lacunae between taxa does not occur during macroevolution, since the “transitional” taxa are separated from the respective descendant and ancestor taxa by lacunae as well. Notably, the evolutionary formation of some higher taxa of birds started with the formation of advanced morphology of the jaw apparatus and the entire skull, while the postcranial skeleton initially remained plesiomorphic.
... In any case, the recognition of W. tedfordi as a presbyornithid certainly calls for a reassessment of the phylogenetic position of Presbyornithidae within Anseriformes (see also [69][70][71]), which may be closer to the base of the anseriform tree than previously assumed [40,47,72]. Similarly, the phylogenetic placement of anseriform fossil taxa that have been based on cladistics analyses with limited taxon sampling and including P. pervetus alone, such as that of the Late Cretaceous Vegavis iaai from Antarctica [72], should be revised in the light of these new findings. ...
Presbyornithids were the dominant birds in Palaeogene lacustrine assemblages, especially in the Northern Hemisphere, but are thought to have disappeared worldwide by the mid-Eocene. Now classified within Anseriformes (screamers, ducks, swans and geese), their relationships have long been obscured by their strange wader-like skeletal morphology. Reassessment of the late Oligocene South Australian material
attributed to Wilaru tedfordi, long considered to be of a stone-curlew (Burhinidae, Charadriiformes), reveals that this taxon represents the first record of a presbyornithid in Australia. We also describe the larger Wilaru prideauxi sp. nov. from the early Miocene of South Australia, showing that presbyornithids survived in Australia at least until ca 22 Ma. Unlike on other continents, where presbyornithids were replaced by aquatic crown-group anatids (ducks, swans and geese), species of Wilaru lived alongside these waterfowl in Australia. The morphology of the tarsometatarsus of these species indicates that, contrary to other presbyornithids, they were predominantly terrestrial birds, which probably contributed to their longterm
survival in Australia. The morphological similarity between species of Wilaru and the Eocene South American presbyornithid Telmabates antiquus supports our hypothesis of a Gondwanan radiation during the
evolutionary history of the Presbyornithidae. Teviornis gobiensis from the Late Cretaceous of Mongolia is here also reassessed and confirmed as a presbyornithid. These findings underscore the temporal continuance of Australia’s vertebrates and provide a new context in which the phylogeny and evolutionary history of presbyornithids can be examined.
... Краниальная морфология пресбиорнитид настолько сходна с таковой современных утиных, что кладистический анализ даже реконструирует их как сестринскую группу Anatidae (Ericson, 1997;Livezey, 1997). Такое систематическое положение пресбиорнитид может быть следствием эффекта умножения синапоморфий (Zelenkov, 2011), поскольку практически вся остальная анатомия этих птиц указывает на их крайнюю примитивность. Плечевая кость пресбиорнитид сходна с таковой примитивных фламингообразных и ржанкообразных, туловищные позвонки имеют опистоцельное строение (сохранилось у очень немногих птиц, например, у попугаев), грудина с двумя парами вырезок (как у курообразных, гусеобразные имеют одну вырезку), дистальный тибиотарзус схож с таковым фламинго (рис. ...
Modern orders of Neornithine birds are separated by distinct morphological gaps, hampering the development of particular models. of macroevolutionary transformations. However, recent decades have witnessed the discovery and extensive study of many fossil groups of birds, which shed light on the origin of modern higher taxa. These fossils further allow analyzing the whole process of the macroevolutionary change in this group of vertebrates during the Cenozoic. Here, a brief review is presented of the "transitional" taxa with special attention to representative of the clade Galloanseres. Almost all transitional groups of fossil birds do display mosaic morphology. It is noted that many stable morphologies (characters and character complexes) persist in different groups, occurring either as primitive states, or as advanced ones. The stable recurrence of these characters is caused by the persistence of stable ontogenetic pathways. On the other hand, independent evolution of various morphologies can be explained by the modular organization of the development. The modularity in the structure of the foot is used here as an example to show a possible way of the origin of the foot in extant perching birds (Passeriformes). The mosaic morphology of the transitional taxa is seen as the only possible way to overcome the evolutionary constraint of the parallel optimization of numerous organismal systems. It is noted that in course of macroevolutionary change, no complete filling of morphological gaps occur. Transitional forms are separated by additional gaps from their ancestors and descendants. Hence, stem groups are seen as the most probable ancestors of crown taxa. It is further noted that the evolutionary formation of some higher taxa of the living birds was initiated by the evolution of advanced morphology of the feeding apparatus and skull, while change in their. postcranial morphology was delayed.
... Parallel evolution is the phenomenon of distantly related and geographically separated groups becoming independently adapted to similar ecological conditions and acquiring similar structural and behavioral traits (Fain and Houde, 2004). A considerable amount of data accumulated over the recent decades suggests that "parallel appearance of characters at different levels is more than common in evolution" (Zelenkov, 2011). In particular, such phenomena as "mammalisation" of theriodonts (Tatarinov, 1976), "arthropodisation" (Ponomarenko, 2005), and "ornithisation" of theropod dinosaurs (Kurochkin, 2006) were described; parallel radiation was demonstrated in various groups of placental mammals (Madsen et al., 2001) and neognathous birds (Fain and Houde, 2004). ...
... For example, the origin of the main orders of birds is believed to have been "accompanied by rapid cladogenesis, so that phylogenetic relations between the orders are extremely difficult to resolve even by the modern molecular methods" (Zelenkov, 2011). The molecular cladogram pattern for Hemiptera can also be interpreted as an indication of rapid diversification of the main groups within the order (Cryan and Urban, 2012). ...
The term “issidisation” is proposed to describe the formation of the specific box-like body shape (including elytra) in several families of planthoppers (Acanaloniidae, Caliscelidae, Issidae, Nogodinidae, and Tropiduchidae). Parallel radiation resulting from adaptation to semi-arid and arid conditions is considered the cause of issidisation. The possibly rapid rate of evolution of higher Fulgoroidea and especially Issidae is discussed. Pyrogenic renewal of Mediterranean-type communities is hypothesized to be the cause of sympatric speciation in the Mediterranean insects.
The presence of Dromornithidae in the Australian Cenozoic fossil record was first reported in 1872, yet although eight species and hundreds of specimens are known, key information on their morphology remains elusive. This is especially so for their skulls, which contributes to a lack of resolution regarding their relationships within Galloanserae. The skull of the Pleistocene dromornithid, Genyornis newtoni, was initially described in 1913. Additional fossils of this species have since been discovered and understanding of avian skull osteology, arthrology, and myological correlates has greatly advanced. Here we present a complete redescription of the skull of Genyornis newtoni, updating knowledge on its morphology, soft-tissue correlates, and palaeobiology. We explore the diversity within Dromornithidae and make comprehensive comparisons to fossil and extant galloanserans. Furthermore, we expand on the homologies of skull muscles, especially regarding the jaw adductors and address the conflicting and unstable placement of dromornithids within Galloanserae. Findings support generic distinction of Genyornis newtoni, and do not support the close association of Dromornithidae and Gastornithidae. We thus recommend removal of the dromornithids from the Gastornithiformes. Considering character polarities, the results of our phylogenetic analyses, and palaeogeography, our findings instead support the alternative hypotheses, of dromornithids within, or close to, the Suborder Anhimae with Anseriformes.
