Newton's parakeet

Newton's parakeet was first recorded by François Leguat in his 1708 memoir A New Voyage to the East Indies. Leguat was the leader of a group of nine French Huguenot refugees who colonised Rodrigues between 1691 and 1693 after they were marooned there. Subsequent accounts were by Julien Tafforet, who was marooned on the island in 1726, in his ''Relation de l'Île Rodrigue'', and then by the French mathematician Alexandre Pingré, who travelled to Rodrigues to view the 1761 transit of Venus. specimen, by John Gerrard Keulemans, 1875 In 1871, George Jenner, the British magistrate of Rodrigues, collected a female specimen; it was preserved in alcohol and given to Edward Newton, a British colonial administrator in Mauritius, who sent it to his brother, the ornithologist Alfred Newton. A. Newton scientifically described the species in 1872 and gave it the scientific name Palaeornis exsul. "Exsul" ("exiled") refers to Leguat, in that he was exiled from France when he gave the first description of the bird. Newton had tried to find a more descriptive name, perhaps based on colouration, but found it difficult. He refrained from publishing a figure of the female in his original description, though the journal Ibis had offered him the space. He instead wanted to wait until a male specimen could be procured since he imagined it would be more attractive. The female, which is the holotype specimen of the species, is housed in the Cambridge University Museum as specimen UMZC 18/Psi/67/h/1. On 14 August 1875, William Vandorous shot a male specimen. This is the paratype of the species, numbered UMZC 18/Psi/67/h/2 and housed in the Cambridge Museum. These two specimens are the only preserved individuals of the species. The mandible and sternum were extracted from the female specimen, and subfossil remains have since been found in the Plaine Corail caverns on Rodrigues. Evolution Based on morphological features, the Alexandrine parakeet (Psittacula eupatria) has been proposed as the founder population for all Psittacula species on Indian Ocean islands, with new populations settling during the species' southwards colonisation from its native South Asia. Features of that species gradually disappear in species further away from its range. Subfossil remains of Newton's parakeet show that it differed from other Mascarene Psittacula species in some osteological features, but also had similarities, such as a reduced sternum, which suggests a close relationship. Skeletal features indicate an especially close relationship with the Alexandrine parakeet and the rose-ringed parakeet (Psittacula krameri), but the many derived features of Newton's parakeet indicates it had long been isolated on Rodrigues. The Psittaculini could have invaded the area several times, as many of the species were so specialised that they may have evolved significantly on hotspot islands before the Mascarenes emerged from the sea. Other members of the genus Psittacula from the Mascarenes include the extant echo parakeet (Psittacula eques echo) of Mauritius, as well as its extinct Réunion subspecies (Psittacula eques eques), and the Mascarene grey parakeet (Psittacula bensoni) of both Mauritius and Réunion. A 2011 genetic study of parrot phylogeny was unable to include Newton's parakeet, as no viable DNA could be extracted. A 2015 genetic study by the British geneticist Hazel Jackson and colleagues included viable DNA from the toe-pad of the female Newton's parakeet specimen. It was found to group within a clade of rose-ringed parakeet subspecies (from Asia and Africa), which it had diverged from 3.82 million years ago. Furthermore, Newton's parakeet appeared to be ancestral to the parakeets of Mauritius and Réunion. The cladogram accompanying the study is shown below: of nearby Mauritius, the closest living relative In 2018, the American ornithologist Kaiya L. Provost and colleagues found the Mascarene parrot (Mascarinus marscarinus) and Tanygnathus species to group within Psittacula, making that genus paraphyletic (an unnatural grouping), and stated this argued for breaking up the latter genus. To solve the issue, the German ornithologist Michael P. Braun and colleagues proposed in 2019 that Psittacula should be split into multiple genera. They placed Newton's parakeet in the new genus Alexandrinus, along with its closest relatives, the echo parakeet and the rose-ringed parakeet. A 2022 genetic study by the Brazilian ornithologist Alexandre P. Selvatti and colleagues confirmed the earlier studies in regard to the relationship between Psittacula, the Mascarene parrot, and Tanygnathus. They suggested that Psittaculinae originated in the Australo–Pacific region (then part of the supercontinent Gondwana), and that the ancestral population of the Psittacula–Mascarinus lineage were the first psittaculines in Africa by the late Miocene (8–5 million years ago), and colonised the Mascarenes from there. == Description ==

Newton's parakeet was about long – roughly the size of the rose-ringed parakeet. It differed from its Mascarene relatives in some skeletal details, including in that the internal margin of the mandibular symphysis (where the two halves of the lower jaw connected) was oval instead of square-shaped when seen from above, and in that the upper end of the humerus (upper arm bone) was less expanded than in the Mascarene grey parakeet and the echo parakeet. Tafforet also described what appears to be green Newton's parakeets, but the issue of colouration was further complicated by the mention of red plumage: In 1987, the British ecologist Anthony S. Cheke proposed that the last two types mentioned were male and female Newton's parakeets, and that the differences between them were due to sexual dimorphism. The last bird mentioned had earlier been identified as introduced grey-headed lovebirds (Agapornis canus) by A. Newton, but Cheke did not find this likely, as their beaks are grey. Pingré also mentioned green birds, perhaps with some red colours, but his account is partially unintelligible and therefore ambiguous. A red shoulder patch is also present on the related Alexandrine parakeet. None of the existing Newton's parakeet specimens have red patches. Fuller suggested the single known male specimen may have been immature, judged on the colour of its beak, and this may also explain the absence of the red patch. When Psittacula are bred by aviculturalists, blue is easily produced from green; the production of blue may suppress red colouration, so blue morphs may have lacked the red patch. == Behaviour and ecology ==

Almost nothing is known about the behaviour of Newton's parakeet, but it is probable that it was similar to that of other members of its genus, such as the echo parakeet. Leguat mentioned that the parrots of the island ate the nuts of the bois d'olive tree (Cassine orientalis). Tafforet also stated that the parrots ate the seeds of the bois de buis shrub (Fernelia buxifolia), which is endangered today, but was common all over Rodrigues and nearby islets during his visit. Newton's parakeet may have fed on leaves as the related echo parakeet does. The fact that it survived long after Rodrigues had been heavily deforested shows that its ecology was less vulnerable than that of, for example, the Rodrigues parrot. Leguat and his men were hesitant to hunt the parrots of Rodrigues because they were so tame and easy to catch. Leguat's group took a parrot as a pet and were able to teach it to speak: The authors of the 2015 study which resolved the phylogenetic placement of the Mascarene island parakeets suggested that the echo parakeet of Mauritius would be a suitable ecological replacement for the Réunion parakeet and Newton's parakeet, due to their close evolutionary relationship. The echo parakeet was itself close to extinction in the 1980s, numbering only twenty individuals, but has since recovered, so introducing it to the nearby islands could also help secure the survival of this species. Many other species endemic to Rodrigues became extinct after humans arrived, and the island's ecosystem remains heavily damaged. Forests had covered the entire island before humans arrived, but very little forestation can be seen today. Newton's parakeet lived alongside other recently extinct birds such as the Rodrigues solitaire, the Rodrigues parrot, the Rodrigues rail, the Rodrigues starling, the Rodrigues scops owl, the Rodrigues night heron, and the Rodrigues pigeon. Extinct reptiles include the domed Rodrigues giant tortoise, the saddle-backed Rodrigues giant tortoise, and the Rodrigues day gecko. == Extinction ==

of Mauritius Of the roughly eight parrot species endemic to the Mascarenes, only the echo parakeet has survived. The others were likely all made extinct by a combination of excessive hunting and deforestation by humans. The Mauritian ornithologist France Staub stated in 1973 that his visits to Rodrigues the previous seven years confirmed the bird was extinct. Hume concluded in 2007 that the islets were probably too small to sustain a population. == References ==