To keep you up to speed, Neornithes developed into Paelognathes (old jaw) and into Neognathes (new jaw). From this group of birds developed some other specifics, but the two of interest to us are the Chardriiformes and the Ciconiiformes. Notice that from the Ciconiiformes stem the Pelecaniformes (obviously containing pelicans), and from the Pelecaniformes stem the Procellariformes, which gave rise to Graviidae (loons, etc.) and Spheniscidae. There's Spheniscidae, our old friend the penguin. So, you can see that the auks, which are often mistaken as being closely related to the penguin due to their similar size, shape and ecological niche, aren't closely related to penguins at all. However, you can see what are closely related to penguins: the Procellariformes from which penguins descend directly, and the Graviidae, which is a daughter clade of the Procellariformes with the Spheniscidae.

    A matter of clarification is necessary at this point. When we speak of fossil penguins, we are referring to the fossil remains of the many species of penguins that have long since vanished from the earth. Their remains are buried in the deep recesses of the crust of the earth or have been obliterated completely. Those that remain are our links to the past, and our tools for education regarding penguin derivation.

    The first fossil penguin found is today held in the British Museum of Natural History. This fossil was reportedly found by an anonymous Maori in New Zealand in the year 1859 and was dubbed Palaeeudyptes antarcticus despite the fact that the species was located a great distance from the continent of Antarctica. Since that great discovery, over the next few years, several more fossils were found and were dated back to the Miocene and three others from the Pliocene. Several specimens were dated to the Late Pliocene and others from the Recent era. According to G.G. Simpson (1975), it is not clear what distinguishes these fossils from modern day Eudyptula, the Little blue penguin and its variants.

    Specimens from Argentina were collected just shy of 1891. Extensive work on these fossil penguins was provided by Florentino Ameghino, and in 1905, he published a rather inclusive report that quickly became source material for the subsequent study of Spheniscus.

G.G. Simpson (1975) provides us with the following table of fossil penguins:

Australia Palaeeudyptes Anthropodyptes gilli Pseudaptenodytes macraei Pseudaptenodytes minor (questionable) New Zealand Palaeeudyptes marplesi Palaeeudyptes (not marplesi) Pachydyptes ponderosus Palaeeudyptes antarcticus Platydyptes marplesi (questionable) Archaeospheniscus lowei Archaeospheniscus lopdelli Duntroonornis parvus Platydyptes novaezealandiae Platydyptes amiesi Korora oliveri Marplesornis novaezealandiae Pygoscelis tyreei Aptenodytes ridgeni

South America Palaeospheniscus gracilis Palaeospheniscus bergi Palaeospheniscus patagonicus Palaeospheniscus wimani Chubutodyptes biloculata Paraptenodytes antarticus Paraptenodytes robustus Paraptenodytes brodkorbi (questionable) Arthrodytes grandis Seymour Island Anthropornis nordenskjoeldii Anthropornis grandis Palaeeudyptes gunnari Wimanornis seymourensis Archaeospheniscus wimani Delphinornis larsenii South Africa Spheniscus predermersus

    The chart above is certainly not exhaustive; there may be many more undiscovered extinct penguins, or extinct penguins that may never be discovered. However, it is evident from the above that at least three of modern penguins (genera: Aptenodytes, Spheniscus, and Pygoscelis) went extinct "recently." By recently, I mean within the last 4-5 million years. The remainder of the penguins stem from 5 to 40 million years ago, basically back to the time currently recorded as when penguins diverged from other modern birds. Research testing suggests that the tallest of these penguins were probably around 6 feet tall.

    The consensus is that penguins did indeed originate from an ancestor that flew some 40 million years ago, quite possibly from the order Procellariformes, as I have already demonstrated. What then caused the present (and past penguins) to lose their capability to fly? A few explanations have arisen. One of these theories is known as "systemic mutation" (Goldschmidt), also known as "typostrophism" (Schindewolf). This account is unlikely since radical changes (flight to no flight) can occur on a small evolutionary scale without the requirement of extensive mutations occurring at once. Nevertheless, the inability to fly is still seen as a viable adaptation, since radical changes that are not adaptations typically lead to extinction. We have already given two possible theories as to how birds acquired flight. Now we have discussed how penguins may have lost that ability to fly.

    Regardless of the adaptations, penguins are southern birds, with only one "tropical" species - the Galapagos penguin (Spheniscus mendiculus). The fossil remains of penguins do not stem far from these southern localities, so it is generally assumed that they came onto the evolutionary scene from these areas. This fact leaves a bit of a mystery to be solved. The earliest avian fossil found in the southern hemisphere is said to have existed in the Eocene age (a period of the Paleogene era of the Cenozoic period -- about 38 to 54 million years ago); Simpson claims this species has "nothing to do with penguins." Hence, the likely suggestion is that the "continental drift" theory accounts for the apparent arrival of flightless species in such remote parts of the world as Antarctica.

    Decent play has been given to the notion that the land mass of the Earth was at one time unified. This land mass was known as Pangaea. Approximately 135 million years ago, Pangaea split into Laurasia and Gondwana. Gondwana contained present day South America, Africa, Antarctica, India and Australia. There was sufficient unity among the regions of Gondwana for birds to develop throughout this region before it split into land masses recognizable by today's geographical standards; this occurred around the end of the Cretaceous period. The heavy tectonic activity may account for some of the spread and speciation of modern penguins.

    Like their modern day descendants, fossil penguins were inshore animals. One of the most affluent sources of fossil penguins happens to be the basal beds of the Chubut River in Patagonia. This area is obviously closely associated with the sea.

    The only exception to this generality has been Spheniscus predemersus, which has been found amongst other terrestrial fauna (Hendey, 1970). Ironically, these fossils were found quite near to certain seal fossils, so it is highly probable that S. predemersus was an inshore animal as well.

    It is widely agreed that earlier penguins were more diverse and much larger than present day species. Simpson claims that these fossil penguins quite extensively populated the Cenozoic era and were the dominant predators of small crustaceans throughout this time, long before seals and their relatives appeared.

    Simpson also assumes that these penguin relatives were "adapted to markedly higher environmental temperatures than the majority of recent penguins." The logical conclusion from this assumption is that modern ψ day penguins carry more equipment that enables them to survive in the colder temperatures, such as more fat reserves, smaller surface areas and less exposed skin. (Again, as one moves further south, penguins become larger - less surface area to volume - and less of the skin is exposed to the environment, e.g. Humboldts compared to Adelies.)

This concludes the Natural Evolution section.

Darwin, Charles. On Evolution. Glick & Kohn, eds. 1996. Hackett Publishing Company, Inc.: Indianapolis.

Krebs, J.R. & Davies, N.B. 1993. An Introduction to Behavioural Ecology. London: Blackwell Scientific Publications.

Krebs, J.R. & Davies, N.B. 1991. Behavioural Ecology: An Evolutionary Approach. London: Blackwell Scientific Publications.

Simpson, G.G., 1975. Fossil Penguins.in Stonehouse,The Biology of Penguins.

Young, David. 1992. The Discovery of Evolution. Cambridge University Press: Cambridge.

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