Red rail
The red rail is an extinct species of rail that was endemic to the Mascarene island of Mauritius, east of Madagascar in the Indian Ocean. It had a close relative on Rodrigues island, the likewise extinct Rodrigues rail, with which it is sometimes considered congeneric, but their relationship with other rails is unclear. Rails often evolve flightlessness when adapting to isolated islands, free of mammalian predators, and that was also the case for this species. The red rail was a little larger than a chicken and had reddish, hairlike plumage, with dark legs and a long, curved beak. The wings were small, and its legs were slender for a bird of its size. It was similar to the Rodrigues rail, but was larger, and had proportionally shorter wings. It has been compared to a kiwi or a limpkin in appearance and behaviour.
This bird is believed to have fed on invertebrates, and snail shells have been found with damage matching an attack by its beak. Human hunters took advantage of an attraction red rails had to red objects by using coloured cloth to lure the birds so that they could be beaten with sticks. Until subfossil remains were discovered in the 1860s, scientists only knew the red rail from 17th century descriptions and illustrations. These were thought to represent several different species, which resulted in a large number of invalid junior synonyms. It has been suggested that all late 17th-century accounts of the dodo actually referred to the red rail, after the former had become extinct. The last mention of a red rail sighting is from 1693, and it is thought to have gone extinct around 1700, due to predation by humans and introduced species.
Taxonomy
The red rail was first mentioned as "Indian river woodcocks" by the Dutch ships' pilot Heyndrick Dircksz Jolinck in 1598. By the 19th century, the bird was known only from a few contemporary descriptions referring to red "hens" and names otherwise used for grouse or partridges in Europe, as well as the sketches of the Dutch merchant Pieter van den Broecke and the English traveller Sir Thomas Herbert from 1646 and 1634. While they differed in some details, they were thought to depict a single species by the English naturalist Hugh Edwin Strickland in 1848. The Belgian scientist Edmond de Sélys Longchamps coined the scientific name Apterornis bonasia based on the old accounts mentioned by Strickland. He also included two other Mascarene birds, at the time only known from contemporary accounts, in the genus Apterornis: the Réunion ibis ; and the Réunion swamphen. He thought them related to the dodo and Rodrigues solitaire, due to their shared rudimentary wings, tail, and the disposition of their digits.File:Aphanapteryx.jpg|thumb|left|upright|First known subfossils which were used to identify this bird as a rail in 1868
The name Apterornis had already been used for a different extinct bird genus from New Zealand by the British biologist Richard Owen earlier in 1848. The meaning of bonasia is unclear. Some early accounts refer to red rails by the vernacular names for the hazel grouse, Tetrastes bonasia, so the name evidently originates there. The name itself perhaps refers to bonasus, meaning "bull" in Latin, or bonum and assum, meaning "good roast". It has also been suggested to be a Latin form of the French word bonasse, meaning simple-minded or good-natured. It is also possible that the name alludes to bulls due the bird being said to have had a similar attraction to the waving of red cloth.
The German ornithologist Hermann Schlegel thought van den Broecke's sketch depicted a smaller dodo species from Mauritius, and that the Herbert sketch showed a dodo from Rodrigues, and named them Didus broecki and Didus herberti in 1854. In 1968, the Austrian naturalist Georg Ritter von Frauenfeld brought attention to paintings by the Flemish artist Jacob Hoefnagel depicting animals in the royal menagerie of Emperor Rudolph II in Prague, including a dodo and a bird he named Aphanapteryx imperialis. Aphanapteryx means "invisible-wing", from Greek aphanēs, unseen, and pteryx, wing. He compared it with the birds earlier named form old accounts, and found its beak similar to that of a kiwi or ibis.
In 1865, subfossil foot bones and a lower jaw were found along with remains of other Mauritian animals in the Mare aux Songes swamp, and were sent by the British ornithologists Edward Newton to the French zoologist Alphonse Milne-Edwards, who identified them as belonging to a rail in 1868. Milne-Edwards correlated the bones with the bird in the Hoefnagel painting and the old accounts, and combined the genus name Aphanapteryx with the older specific name broecki. Due to nomenclatural priority, the genus name was later combined with the oldest species name bonasia. In the 1860s, the travel journal of the Dutch East India Company ship Gelderland was rediscovered, which contains good sketches of several now-extinct Mauritian birds attributed to the Dutch artist Joris Laerle, including an unlabelled red rail.
More fossils were later found by the French naturalist Theodore Sauzier, who had been commissioned to explore the "historical souvenirs" of Mauritius in 1889, and these were described by Newton and the German ornithologist Hans F. Gadow in 1893. In 1899, an almost complete specimen was found by the French barber Louis Etienne Thirioux, who also found important dodo remains, in a cave in the Vallée des Prêtres; this is the most completely known red rail specimen, and is catalogued as MI 923 in the Mauritius Institute. The second most complete individual also mainly consists of bones from the Thirioux collection. More material has since been found in various settings. The yellowish colouration mentioned by English traveller Peter Mundy in 1638 instead of the red of other accounts was used by the Japanese ornithologist Masauji Hachisuka in 1937 as an argument for this referring to a distinct genus and species, Kuina mundyi, but the American ornithologist Storrs L. Olson suggested in 1977 that it was possibly due to the observed bird being a juvenile red rail.
Evolution
Apart from being a close relative of the Rodrigues rail, the relationships of the red rail are uncertain. The two are commonly kept as separate genera, Aphanapteryx and Erythromachus, but have also been united as species of Aphanapteryx at times. They were first generically synonymised by Newton and Albert Günther in 1879, due to skeletal similarities. In 1892, the Scottish naturalist Henry Ogg Forbes described Hawkins's rail, an extinct species of rail from the Chatham Islands located east of New Zealand, as a new species of Aphanapteryx; A. hawkinsi. He found the Chatham Islands species more similar to the red rail than the latter was to the Rodrigues rail, and proposed that the Mascarene Islands had once been connected with the Chatham Islands, as part of a lost continent he called "Antipodea". Forbes moved the Chatham Islands bird to its own genus, Diaphorapteryx, in 1893, on the recommendation of Newton, but later reverted to his older name. The idea that the Chatham Islands bird was closely related to the red rail and the idea of a connection between the Mascarenes and the Chatham Islands were later criticised by the British palaeontologist Charles William Andrews due to no other species being shared between the islands, and Gadow explained the similarity between the two rails as parallel evolution.In 1945, the French palaeontologist Jean Piveteau found skull features of the red and Rodrigues rail different enough for generic separation, and in 1977, Olson stated that though the two species were similar and derived from the same stock, they had also diverged considerably, and should possibly be kept separate. Based on geographic location and the morphology of the nasal bones, Olson suggested that they were related to the genera Gallirallus, Dryolimnas, Atlantisia, and Rallus. The American ornithologist Bradley C. Livezey was unable to determine the affinities of the red and Rodrigues rail in 1998, stating that some of the features uniting them and some other rails were associated with the loss of flight rather than common descent. He also suggested that the grouping of the red and Rodrigues rail into the same genus may have been influenced by their geographical distribution. The French palaeontologist Cécile Mourer-Chauviré and colleagues also considered the two as belonging to separate genera in 1999.
Rails have reached many oceanic archipelagos, which has frequently led to speciation and evolution of flightlessness. According to the British researchers Anthony S. Cheke and Julian P. Hume in 2008, the fact that the red rail lost much of its feather structure indicates it was isolated for a long time. These rails may be of Asian origin, like many other Mascarene birds. In 2019, Hume supported the distinction of the two genera, and cited the relation between the extinct Mauritius scops owl and the Rodrigues scops owl as another example of the diverging evolutionary paths on these islands. He stated that the relationships of the red and Rodrigues rails was more unclear than that of other extinct Mascarene rails, with many of their distinct features being related to flightlessness and modifications to their jaws due to their diet, suggesting long time isolation. He suggested their ancestors could have arrived on the Mascarenes during the middle Miocene at the earliest, but it may have happened more recently. The speed of which these features evolved may also have been affected by gene flow, resource availability, and climate events, and flightlessness can evolve rapidly in rails, as well as repeatedly within the same groups, as seen in for example Dryolimnas, so the distinctness of the red and Rodrigues rails may not have taken long to evolve. Hume suggested that the two rails were probably related to Dryolimnas, but their considerably different morphology made it difficult to establish how. In general, rails are adept at colonising islands, and can become flightless within few generations in suitable environments, for example without predators, yet this also makes them vulnerable to human activities.