Ducks, like almost all taxonomic categories, are a nightmare for creationists because they aren't mentioned in the Bible so it's not possible to put them into their primitive 'kind' classification, other than saying they are some 'kind' of bird, or maybe a 'duck kind'. The problem is there are so many different families of duck and several different species within each family. Some of them look very different to other ducks and have clearly evolved unique characteristics such as the long, serrated beak of the fish-eating mergansers, which places them in a different clade to the dabbling diving and torrent ducks.
By any definition then, evolving from a basic 'duck' into a merganser is the evolution of a new taxon, or 'macro-evolution' as creationists like to call it, while proclaiming it to be impossible because of some undefined magical process that intervenes to prevent it.
Which leaves creationists with nowhere to go but to claim mergansers were on the Ark, since they couldn't have evolved from a parent pair of 'ducks' at the abnormal warp-speed rate of evolution, that no-one noticed or thought to record, that creationists now claim must have happened in the few years since their favourite genocidal flood, that left no trace of itself.
But that's nothing compared to the genetic evidence that shows how, for example, the mergansers, evolved and spread geographically 18 million years before creationists believe there was a universe and again between 14 and 7 million years before creationists' god decided to create a small flat planet with a dome over it in the Middle East, 10,000 years ago, that creationists still believe accurately describes all that there is.
First, a little AI information about mergansers:
Tell me all about mergansers, their distribution and evolutionary origins, please. Mergansers are a group of ducks belonging to the genus Mergus, which is part of the family Anatidae. They are known for their distinctive serrated bills, which are well-adapted for catching fish, their primary diet. Here’s a detailed overview of mergansers, including their distribution, characteristics, and evolutionary background.
Characteristics Mergansers are medium to large-sized ducks with slender bodies and long, pointed bills. Their bills are equipped with saw-like edges that help them grasp slippery fish. There are several species within the Mergus genus, including:
- Common Merganser (Mergus merganser): Also known as the goosander, this species has a widespread distribution across North America, Europe, and Asia.
- Red-breasted Merganser (Mergus serrator): Found in North America, Europe, and Asia, this species prefers coastal and large inland waters.
- Hooded Merganser (Lophodytes cucullatus): Native to North America, it is smaller than other mergansers and has a distinctive fan-shaped crest.
- Brazilian Merganser (Mergus octosetaceus): One of the rarest mergansers, it is found in central Brazil and is critically endangered.
- Scaly-sided Merganser (Mergus squamatus): This species inhabits parts of East Asia and is also considered endangered.
Distribution
Mergansers have a wide distribution, with different species occupying various regions around the globe:
- Common Merganser: Breeds in forested regions near lakes and rivers across northern North America, Europe, and Asia. In winter, they migrate to more temperate areas.
- Red-breasted Merganser: Found in boreal and temperate regions across the Northern Hemisphere. They often winter in coastal waters, estuaries, and large inland lakes.
- Hooded Merganser: Prefers forested wetlands, rivers, and ponds in North America. They are non-migratory in some parts of their range but move to ice-free waters in winter.
- Brazilian Merganser: Restricted to central Brazil, particularly in the Serra da Canastra region. Their habitat includes clear, fast-flowing rivers.
- Scaly-sided Merganser: Breeds in forested rivers of northeast China and the Russian Far East. They migrate to southern China, Korea, and Japan for winter.
Evolution
Mergansers belong to the Anatidae family, which includes ducks, geese, and swans. The evolution of mergansers is part of the broader adaptive radiation of the Anatidae, which diversified to exploit a variety of ecological niches. The serrated bills of mergansers are a specialized adaptation for piscivory (fish-eating), differentiating them from other ducks.
Evolutionary Background
- Ancestral Origins: The Anatidae family likely originated in the late Cretaceous to early Paleogene periods. Early diversification allowed these birds to adapt to various ecological roles, including herbivory, omnivory, and piscivory.
- Adaptive Radiation: The diversification of Mergus species is an example of adaptive radiation, where different species evolved to occupy different ecological niches, particularly in terms of habitat preference and diet specialization.
- Morphological Adaptations: The distinctive serrated bills of mergansers are a key evolutionary trait that sets them apart from other ducks. This adaptation is crucial for their fish-based diet.
Conservation Status
Several species of mergansers are of conservation concern:
- Brazilian Merganser: Critically endangered, with an estimated population of fewer than 250 individuals in the wild. Habitat destruction and water pollution are major threats.
- Scaly-sided Merganser: Endangered, with threats including habitat loss due to logging and river damming, as well as pollution and human disturbance.
Conclusion
Mergansers are a fascinating group of ducks with specialized adaptations that enable them to thrive as piscivores in a variety of aquatic habitats. Their wide distribution and evolutionary history reflect the dynamic processes of diversification and adaptation in the Anatidae family. Conservation efforts are crucial for the survival of the endangered species within this group, highlighting the need for habitat protection and restoration.
The evidence of when the now extinct New Zealand merganser got to New Zealand and how it is related to other mergansers is the subject of an article in The Conversation by Nic Rawlence, Senior Lecturer in Ancient DNA, and Alexander Verry, Researcher, both of the University of Otago, New Zealand. Their article is reprinted here under a Creative Commons license, reformatted for stylistic consistency:
Ancient DNA from an extinct native duck reveals how far birds flew to make New Zealand home
Auckland Island merganser. Artistic reconstruction by J. G. Keulemans from Bullers Birds of New Zealand (1888)
Nic Rawlence, University of Otago and Alexander Verry, University of OtagoBullers Birds of New Zealand, Author provided
Ask a bird lover if they have heard of the extinct giant moa or its ancient predator, Haast’s eagle, and the answer will likely be yes. The same can’t be said of New Zealand’s extinct, but equally unique, mergansers – a group of fish-eating ducks with a serrated bill.
The only southern hemisphere representatives of this group are the critically endangered Brazilian merganser and those from the New Zealand region, which are now extinct.
Unlike some of New Zealand’s other extinct birds, the biological heritage of our enigmatic mergansers is shrouded in mystery. But our new research on the extinct Auckland Island merganser is changing the way we think about the origins of New Zealand’s birds. Did the ancestors of the merganser come from South America or the northern hemisphere – and when did they arrive?
Mergansers are relatively common in the northern hemisphere but were limited to Brazil and the New Zealand region in the southern hemisphere.
Author provided
Mergansers were spread across the three main islands of New Zealand at the time of Polynesian arrival in the 13th century, as well as the Auckland Islands to the south and the Chatham Islands to the east.
Over-hunting, habitat destruction, and predation from the Pacific rat and Polynesian dog resulted in the extinction of mergansers on the New Zealand mainland and the Chatham Islands. By the time Europeans arrived in the 17th century, mergansers were restricted to an isolated population on the sub-Antarctic Auckland Islands.
European discovery of the Auckland Islands in 1806 led to a formal description of the Auckland Island merganser in 1841. However, European discovery brought new predators like pigs and cats.
Mergansers were also sought after as specimens for the museum trade. The last known Auckland Island merganser was shot and collected in 1902, a mere 61 years after its discovery.
Auckland Island Merganser, Mergus australis, collected June 1902, Auckland Islands, New Zealand.
From the northern hemisphere to NZ
The extinction of mergansers from the New Zealand region has meant their evolutionary history has remained a mystery. Did their ancestors, and those of the Brazilian merganser, arrive via independent colonisation events from the northern hemisphere? Or was there a single push into the southern hemisphere, followed by subsequent divergence events?
To find out more, we sequenced ancient DNA from an Auckland Islands merganser and a Brazilian merganser. This allowed us to reconstruct the evolutionary history of the wider group.
We found mergansers originated in the northern hemisphere, diverging from their closest relatives some 18 million years ago, before rapidly evolving into several different species between 14 and seven million years ago.
The mergansers from the New Zealand region are most closely related to the northern hemisphere common merganser. Their ancestors arrived here at least seven million years ago in a separate colonisation event to the one that gave rise to the Brazilian merganser.
Further genetic research is currently underway. The goal is to reconstruct the evolutionary history of mergansers within the New Zealand region.
The global origins of New Zealand’s birds
Many New Zealanders believe the country’s native birds originate from Australia. Increasingly though, genetic and palaeontological research shows a number of our feathered friends hail from further afield.
Kiwi are most closely related to the extinct elephant birds of Madagascar, for example. And the extinct adzebill is related to flufftails, also from Madagascar. The extinct moa is most closely related to the tinamou from South America.
The long journey of blue-eyed shags started in South America, with the birds island hopping via Antarctica and the sub-Antarctic islands to New Zealand. Mergansers arriving from the northern hemisphere add another piece to the puzzle.
It is possible that fossils of extinct mergansers (and other birds with distant geographic origins) will be discovered as palaeontologists increasingly focus on previously neglected and newly discovered southern hemisphere fossil deposits.
Only then, combined with the power of ancient DNA, will we be able to fully understand how New Zealand’s dynamic geological, climatic and human history has influenced the colonisation and diversification of birds on this isolated South Pacific archipelago.
Nic Rawlence, Senior Lecturer in Ancient DNA, University of Otago and Alexander Verry, Researcher, Department of Zoology, University of Otago
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Creationists needn't be too embarrassed by these facts about the distribution and evolution of mergansers, after all, the simple Bronze Age Canaanites who made up the origin myths to fill the gaps in their knowledge and understanding, could have known nothing of them, since they are largely absent from the Middle East, nor of southern hemisphere land masses such as South America, Australia and New Zealand when they didn't even realise there is a southern hemisphere, or of the ducks and their families.Abstract
Mergansers are riverine and coastal piscivorous ducks that are widespread throughout North America and Eurasia but uncommon in the Southern Hemisphere. One species occurs in South America and at least two extinct species are known from New Zealand. It has been proposed that these Southern Hemisphere merganser lineages were founded by at least two independent dispersal events from the Northern Hemisphere. However, some morphological and behavioural evidence suggests that Southern Hemisphere mergansers may form a monophyletic clade that descended from only a single dispersal event from the Northern Hemisphere. For example, Southern Hemisphere mergansers share several characteristics that differ from Northern Hemisphere mergansers (e.g. non-migratory vs. migratory, sexual monochromatism vs. sexual dichromatism, long vs. short pair bonds). We sequenced complete mitogenomes from the Brazilian merganser and an extinct merganser from New Zealand—the Auckland Island merganser. Our results show that the Brazilian and Auckland Island mergansers are not sister-taxa, and probably descend from two separate colonization events from the Northern Hemisphere at least 7 Mya. Nuclear (palaeo)genomic data may help to further resolve the relationship between living and extinct mergansers, including merganser fossils from New Zealand that have not been subjected to palaeogenetic analysis.
INTRODUCTION
Mergansers (Mergus spp.) are a group of riverine and seasonally coastal fish-eating ducks that have a widespread Northern Hemisphere distribution but are uncommon in the Southern Hemisphere (Kear 2005, Williams et al. 2012, 2014) (Fig. 1). They are characterized by a serrated bill, and include the endangered scaly-sided merganser (M. squamatus Gould 1864) from north-east Asia; the common merganser (M. merganser Linnaeus 1758), and the red-breasted merganser (M. serrator Linnaeus 1758), which have widespread Northern Hemisphere distributions; the critically endangered Brazilian merganser (M. octosetaceus Vieillot 1817); and two currently recognized extinct species from the New Zealand region—M. australis Hombron and Jacquinot 1841 and M. milleneri Williams and Tennyson 2014 from the Auckland and Chatham Islands, respectively. While the hooded merganser Lophodytes cucullatus (Linnaeus 1758), previously M. cucullatus, from North America has a serrated bill, it is not considered a ‘true’ merganser (e.g. Buckner et al. 2018, Lavretsky et al. 2021). The taxonomic relationship of the smew Mergellus albellus (Linnaeus 1758) from Eurasia is currently unresolved; it is sometimes suggested to be more closely related to Mergus and Lophodytes or to goldeneyes (Bucephala spp.) (Livezey 1995, Buckner et al. 2018, Lavretsky et al. 2021).The now extinct Auckland Island merganser M. australis (or miuweka) (Fig. 2) was formally described in 1841, based on a specimen collected on the sub-Antarctic Auckland Islands, 465 km south of mainland New Zealand. Rare Late Holocene-aged merganser bones have been found in coastal sand dune deposits (including Māori middens) on New Zealand’s three main islands (Stewart, North, and South), and the Auckland and Chatham Islands (Tennyson and Martinson 2007, Williams et al. 2014, Tennyson 2020). Bones from the latter were recently described as a distinct species M. milleneri, which was smaller than the nominate M. australis, with a shorter skull, relatively shorter premaxilla, smaller sternum and keel, relatively shorter wing bones, and a narrower pelvis (Williams et al. 2014). The taxonomic status of merganser bones from mainland New Zealand is unresolved (i.e. cannot be assigned to either M. australis or M. milleneri), and are currently recognized as Mergus spp. (Birds New Zealand Checklist Committee 2022).Figure 1.Schematic of the breeding distributions of Mergus spp. The New Zealand (NZ) lineage encompasses the Auckland Island merganser (465 km south of NZ) and Chatham Island merganser (785 km east of NZ), as well as Mergus spp. from mainland NZ. Breeding distributions are based off the Cornell Lab of Ornithology Birds of the World website.Mergansers in the New Zealand region are mainly thought to have occupied a riverine and seasonally coastal habitat (e.g. sheltered bays during winter; Kear 2005, Williams et al. 2012, 2014). It is likely that they mainly nested in tree cavities, but also caves in some instances, as the remains of adults, chicks, and eggs have been found within a cave on the Chatham Islands (Williams et al. 2014). By the 17th century, mergansers had been extirpated from the Chatham Islands and mainland New Zealand, and survived only on the Auckland Islands. A combination of subsistence hunting, and predation from the Pacific rat (Rattus exulans) and Polynesian dog (Canis familiaris), probably led to the extinction of mergansers across most of their prehistoric range (Tennyson and Martinson 2007, Greig and Rawlence 2021.1). On the Auckland Islands, predation from introduced pigs (Sus scrofa) and cats (Felis catus), and collecting for the museum trade, resulted in their extinction—indeed the last known Auckland Island merganser specimen was shot and collected in January 1902 (Williams 2012.1).Figure 2.In the Southern Hemisphere, mergansers are only known from the New Zealand region and South America, represented here by the Auckland Island merganser. A, artistic reconstruction by J.G. Keulemans from Buller (1888); B, historical museum skin (Museum of New Zealand Te Papa Tongarewa OR.001357); C, the Brazilian merganser (photo by Savio Freire Bruno CC BY-SA 3.0).
The only extant merganser in the Southern Hemisphere—the critically endangered Brazilian merganser (Fig. 2)—is one of the rarest birds in the world, comprising only 250 wild individuals. It is split across three remnant populations in Brazil, but once had a more widespread historical distribution encompassing Argentina and Paraguay (Vilaca et al. 2012.2, Maia et al. 2020.1). The Brazilian merganser has undergone a significant population bottleneck, yet different remnant populations can still be genetically identified (Maia et al. 2020.1). Like mergansers from the New Zealand region, the Brazilian merganser occupies riverine habitats, and often nests in tree cavities or rock crevasses (Vilaca et al. 2012.2, Maia et al. 2020.1).
It has been proposed that the Southern Hemisphere mergansers were founded by independent dispersal events to the New Zealand region and South America from the Northern Hemisphere (e.g. Livezey 1995). Based on behavioural characteristics, Johnsgard (1961) tentatively assigned the Brazilian merganser as sister-species to a clade comprising the other Mergus species, with the Auckland Island merganser as the sister-species of the common merganser and scaly-sided merganser. In contrast, using morphological characters, Livezey (1989, 1995) assigned the Auckland Island merganser, then Brazilian merganser, as successive sister-species to all other Mergus species, though with weak to moderate bootstrap support. Using mitochondrial DNA (mtDNA) sequences, Buckner et al. (2018) suggested the Brazilian merganser was the sister-species to the scaly-sided merganser, albeit with weak support. However, some evidence suggests that Southern Hemisphere mergansers may be closely related to one another, potentially even sister-species, as they share several behavioural (e.g. non-migratory and long pair bonds) and morphological (e.g. sexually monochromatic) characteristics, in contrast to their Northern Hemisphere congeners (e.g. migratory, short pair bonds, and sexual dichromatism; Livezey 1995). In addition, recent genetic studies of other extinct Southern Hemisphere avian species have also revealed unexpected evolutionary connections between birds from New Zealand, South America, and Africa (e.g. Mitchell et al. 2014.1a, 2014.2b, Boast et al. 2019, Rawlence et al. 2022.1, Verry et al. 2022.2a). As such, the phylogenetic relationships of the Southern Hemisphere mergansers, when their ancestors arrived in the region, and from where, remain unresolved.
In this study, the first genetic study of a New Zealand Mergus species, we sequenced mitochondrial genomes (mitogenomes) from historical museum specimens from the Auckland Island merganser and Brazilian merganser, and analysed them within a phylogenetic framework of Mergini mitogenomes (Liu et al. 2012.3, Lavretsky et al. 2021). These data were used to determine the phylogenetic relationships and divergence dates within mergansers.
Nicolas J Rawlence, Alexander J F Verry, Theresa L Cole, Lara D Shepherd, Alan J D Tennyson, Murray Williams, Jamie R Wood, Kieren J Mitchell
Ancient mitogenomes reveal evidence for the Late Miocene dispersal of mergansers to the Southern Hemisphere Zoological Journal of the Linnean Society, 2024;, zlae040, https://doi.org/10.1093/zoolinnean/zlae040
Copyright: © 2024 The authors.
Published by Oxford University Press on behalf of The Linnean Society of London. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
And, of course, they knew nothing about the history of Earth and the life on it, so how could they be expected to have known about the evolutionary history and geographic distribution of these ducks? With their long, serrated beaks and fish diet, they probably wouldn't have recognised mergansers as a type of duck even.
All they had to draw on was their limited knowledge of the small scrap of the globe they inhabited, which is why they got almost everything they described so hopelessly wrong. The lesson from Genesis is just how badly you do when you know little and depend on guesswork from the point of view of someone with the knowledge understanding of a pre-school toddler of today.
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