Rodrigues solitaire

The French explorer François Leguat was the first to refer to the bird as the "solitaire" (referring to its solitary habits), but it has been suggested that he borrowed the name from a 1689 tract by his sponsor Marquis Henri Duquesne, which used the name "solitaire" in reference to the Réunion ibis. The bird was first scientifically named in 1789 as a species of dodo (Didus solitarius, based on Leguat's description) by the German naturalist Johann Friedrich Gmelin in the thirteenth edition of Systema Naturae. In 1786, subfossil Rodrigues solitaire bones encrusted in stalagmite were discovered in a cave on Rodrigues and sent to the French naturalist Georges Cuvier in about 1830. For unknown reasons, he stated they had recently been found on Mauritius, which caused confusion, until they were compared with other bones found on Rodrigues in 1831 that were shown to belong to the same, distinct species by the English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in 1848. Strickland and Melville suggested the common descent of the Rodrigues solitaire and the dodo in their 1848 monograph about the latter. They dissected the only known dodo specimen with soft tissue, comparing it with the few Rodrigues solitaire remains then available. They stated that, although not identical, these birds shared many distinguishing features in the leg bones otherwise only known in pigeons. The fact that the Rodrigues solitaire laid only one egg, fed on fruits, was monogamous and cared for its nestlings also supported this relationship. Strickland recognised its generic distinction and named the new genus Pezophaps, from ancient Greek '''' ( 'pedestrian') and '''' ( 'pigeon'). The differences between the sexes of the bird were so large that Strickland thought they belonged to two species, naming the smaller female bird Pezophaps minor in 1852. Additional subfossils were recovered during the 1860s, but more complete remains were found during the 1874 transit of Venus, since an observation station was located on the island. Study of skeletal features by the Newtons indicated that the solitaire was morphologically intermediate between the dodo and ordinary pigeons, but differed from them in its unique carpal knob. An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led the British taxidermist Abraham Dee Bartlett to name a new species in 1851, Didus nazarenus; it is now a junior synonym of this species. At one point it was suggested that the skeleton of this species is the best described after that of humans. In spite of the evidence, some later scholars doubted Leguat's story, and the existence of the Rodrigues solitaire. In 1921, the American linguist Geoffroy Atkinson claimed Leguat's memoir was merely a novel, and that the man had never even existed, and in 1955, the British ecologist George Evelyn Hutchinson doubted aspects of the bird's biology mentioned by Leguat. Today, it is widely accepted that Leguat's memoirs are credible observations of the bird in life. For many years the dodo and the Rodrigues solitaire were placed in a family of their own, the Raphidae (formerly Dididae), because their exact relationships with other pigeons were unresolved. Each was also placed in a monotypic family (Raphidae and Pezophapidae, respectively), as it was thought that they had evolved their similarities independently. Osteological and DNA analysis has since led to the dissolution of the family Raphidae, and the dodo and solitaire are now placed in the columbid subfamily Raphinae and tribe Raphini, along with their closest relatives. In 2024, the new subtribe Raphina was created to include only the dodo and the solitaire. Evolution In 2002, American geneticist Beth Shapiro and colleagues analysed the DNA of the dodo and the Rodrigues solitaire for the first time. Comparison of mitochondrial cytochrome b and 12S rRNA sequences isolated from the femur of a Rodrigues solitaire and the tarsal of a dodo confirmed their close relationship and their placement within the Columbidae. The genetic evidence was interpreted as showing the Southeast Asian Nicobar pigeon (Caloenas nicobarica) to be their closest living relative, followed by the crowned pigeons (Goura) of New Guinea, and the superficially dodo-like tooth-billed pigeon (Didunculus strigirostris) from Samoa. This clade consists of generally ground-dwelling island endemic pigeons. The following cladogram shows the closest relationships of the dodo and the Rodrigues solitaire within Columbidae, based on Shapiro et al., 2002: , the closest living relative of the Rodrigues solitaire and the dodo according to DNA studies }} A similar cladogram was published in 2007, inverting the placement of Goura and Didunculus and including the pheasant pigeon (Otidiphaps nobilis) and the thick-billed ground pigeon (Trugon terrestris) at the base of the clade. Based on behavioural and morphological evidence, Jolyon C. Parish proposed that the dodo and Rodrigues solitaire should be placed in the Gourinae subfamily along with the Goura pigeons and others, in agreement with the genetic evidence The 2002 study indicated that the ancestors of the Rodrigues solitaire and the dodo diverged around the Paleogene–Neogene boundary. The Mascarene Islands (Mauritius, Réunion, and Rodrigues), are of volcanic origin and are less than 10 million years old. Therefore, the ancestors of both birds probably remained capable of flight for a considerable time after the separation of their lineage. The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae, which indicates the flightless raphines had ancestors that were able to fly, were semi-terrestrial, and inhabited islands. This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia. The dodo lost the ability to fly owing to the lack of mammalian predators on Mauritius. Another large, flightless pigeon, the Viti Levu giant pigeon (Natunaornis gigoura), was described in 2001 from subfossil material from Fiji. It was only slightly smaller than the Rodrigues solitaire and the dodo, and it too is thought to have been related to the crowned pigeons. ==Description==

, 1907 The beak of the Rodrigues solitaire was slightly hooked, and its neck and legs were long. One observer described it as the size of a swan. The skull was long, flattened at the top with the fore and hind parts elevated into two bony ridges structured with cancellous bone. A black band (a contemporary description described it as a "frontlet") appeared on its head just behind the base of the beak. The plumage of the Rodrigues solitaire was described as grey and brown. Females were paler than males and had elevations on the lower neck. Males were considerably larger than females, measuring in height and weighing up to , whereas females were and weighed up to . This is only 60% of the weight of a mature male. He described its appearance as follows: Several of Leguat's observations were later confirmed through study of subfossil Rodrigues solitaire remains. The curved contour lines of the pelvis also support the roundness of its hind parts, which he compared to that of a horse. Also, a ridged surface appears at the base of the beak, indicating the position of the caruncular ridge, which Leguat described as a "widow's peak". Before fossils of the carpal knob were found, Strickland noted that the keel of the sternum of the Rodrigues solitaire was so well-developed as to almost indicate it had possessed the power of flight; however, since the humerus was very short he inferred that this was instead related to Leguat's claim that they used their wings for defence. Leguat continued with an elaborate description of the female Rodrigues solitaire, which also appears to be the sex depicted in his illustration of the bird: It has been proposed that Leguat's comparison between the crop of the female Rodrigues solitaire and the "beautiful bosom of a woman" (changed to "fine neck" in some editions of his memoirs) was out of longing for female companionship. Leguat's statements were confirmed by another description by Julien Tafforet, who wrote in 1726: ==Behaviour and ecology==

Some evidence, including their large size and the fact that tropical and frugivorous birds have slower growth rates, indicates that the Rodrigues solitaire may have had a protracted development period. Based on mass estimates, the American ornithologist Bradley C. Livezey suggested in 1993 the male could reach the age of 28, and the female 17. The species may have lived primarily in the island's woodlands, rather than on the shores. Diet Leguat stated that the Rodrigues solitaire fed on dates, whereas Tafforet mentioned seeds and leaves. No other accounts mention diet. Several contemporary accounts state that the Rodrigues solitaire used gizzard stones. Dodos also did this, which may imply a similar diet. Fractures in their wing bones also indicate that they were used in combat. The British palaeontologists Julian P. Hume and Lorna Steel pointed out in 2013 that in all extant birds where carpal spurs and knobs are present, these are used as weapons without exceptions. Though some dodo bones have been found with healed fractures, it had weak pectoral muscles and more reduced wings in comparison with the Rodrigues solitaire. Since Rodrigues receives less rainfall and has more seasonal variation than Mauritius, which would have affected the availability of resources on the island, the Rodrigues solitaire would have more reason to evolve aggressive territorial behaviour. Reproduction The most detailed account of the reproductive habits of the Rodrigues solitaire is Leguat's. He described mating and nesting as follows: The clutch was described as consisting of a single egg; given the bird's large size, this led to proposals that the solitaire was K-selected, which means it produced a low number of altricial offspring, which required extensive parental care until maturity. The gathering of unrelated juveniles suggests that they formed crèches, which may have followed foraging adults as part of the learning process.|alt=Greyish bird Tafforet's account confirms Leguat's description of reproductive behaviour, adding that Rodrigues solitaires would even attack humans approaching their chicks: The size difference between sexes has led to the suggestion that the Rodrigues solitaire was not monogamous as stated by Leguat, and that this deeply religious man attributed the trait to the bird for moral reasons. However, size dimorphism does occur in some monogamous birds; most other pigeons are monogamous as well. ==Relationship with humans==

The Dutch viceadmiral Hans Hendricksz Bouwer was the first to list "dodos", most likely referring to the Rodrigues solitaire, as part of the fauna of Rodrigues in 1601. The English traveller Sir Thomas Herbert mentioned "dodos" on Rodrigues again in 1634, and they were also mentioned in 1700. Leguat was the leader of a group of nine French Huguenot refugees, who were the first to colonise the island from 1691 to 1693, after they were marooned there by their captain. His description of the Rodrigues solitaire and its behaviour is the most detailed account of the bird in life, and he also described other species that are now extinct. Leguat's observations are considered some of the first cohesive accounts of animal behaviour in the wild. He later left for Mauritius, but was too late to observe dodos there. to Leguat's 1708 memoir, showing his settlement on Rodrigues, and a solitaire in the middle|alt=Drawing of houses on Rodrigues The Huguenots praised the Rodrigues solitaires for their flavour, especially that of the young, and used their gizzard stones as knife sharpeners. D'Héguerty later claimed these were also useful in medicine, and referred to them as bezoars. The second most detailed description of the bird was found in an anonymous document rediscovered in 1874 called ''Relation de l'Ile Rodrigue'', which has been attributed to Julien Tafforet, a mariner marooned on Rodrigues in 1726. His observations are considered credible, though it is known he had a copy of Leguat's memoirs with him during his stay. Many old accounts mention that Rodrigues solitaires were hunted by humans. The Danish zoologist Japetus Steenstrup noted that some Rodrigues solitaire remains bore traces of having been broken by a human or perhaps another large predator, to extract bone marrow. Writing in 1735, the French lieutenant Gennes de la Chancelière described the capture and consumption of two specimens as follows: Unlike the dodo, no Rodrigues solitaires are known to have been sent to Europe alive. However, it has been claimed that the French naval officer Bertrand-François Mahé de La Bourdonnais sent a "solitaire" to France from the nearby island of Réunion around 1740. Since the Réunion solitaire is believed to have become extinct by this date, the bird may actually have been a Rodrigues solitaire. Extinction Turdus Solitarius was named after the Rodrigues solitaire, here depicted in Uranographia by Johann Elert Bode, 1801 The Rodrigues solitaire probably became extinct sometime between the 1730s and 1760s; the exact date is unknown. Its disappearance coincided with the tortoise trade between 1730 and 1750; traders burnt off vegetation, hunted solitaires and imported cats and pigs that preyed on eggs and chicks. In 1755, the French engineer Joseph-François Charpentier de Cossigny attempted to obtain a live specimen, as he had been assured the Rodrigues solitaire still survived in remote areas of the island. Though trying for 18 months, and offering large rewards, none could be found. He noted that cats were blamed for decimating the species, but suspected that it was due to hunting by humans instead. The French astronomer Alexandre Guy Pingré did not encounter any solitaires when he visited Rodrigues to observe the 1761 transit of Venus, although he had been assured they survived. His friend, the French astronomer Pierre Charles Le Monnier named the constellation Turdus Solitarius after the bird to commemorate the journey. Although the Rodrigues solitaire is the only extinct bird to have a former constellation named for it, celestial mapmakers did not know what it looked like and star maps depicted other birds. By the time the discovery of subfossil Rodrigues solitaire bones from 1786 onwards confirmed Leguat's descriptions, no living residents of Rodrigues remembered having seen live specimens. In 1831, a man who had lived on Rodrigues for 40 years said that he had never seen birds large enough to be Rodrigues solitaires. Rodrigues covers only , making it implausible that the bird would have survived undetected. ==References==