SciCombinator

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Concept: Rodrigues Solitaire

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The dodo, Raphus cucullatus, a flightless pigeon endemic to Mauritius, became extinct during the 17(th) century due to anthropogenic activities. Although it was contemporaneous with humans for almost a century, little was recorded about its ecology. Here we present new aspects of the life history of the dodo based on our analysis of its bone histology. We propose that the dodo bred around August and that the rapid growth of the chicks enabled them to reach a robust size before the austral summer or cyclone season. Histological evidence of molting suggests that after summer had passed, molt began in the adults that had just bred; the timing of molt derived from bone histology is also corroborated by historical descriptions of the dodo by mariners. This research represents the only bone histology analysis of the dodo and provides an unprecedented insight into the life history of this iconic bird.

Concepts: Bird, Columbidae, Flightless bird, Mauritius, Columbiformes, Dodo, Raphinae, Rodrigues Solitaire

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The dodo (Raphus cucullatus) might be the most enigmatic bird of all times. It is, therefore, highly remarkable that no consensus has yet been reached on its body mass; previous scientific estimates of its mass vary by more than 100%. Until now, the vast amount of bones stored at the Natural History Museum in Mauritius has not yet been studied morphometrically nor in relation to body mass. Here, a new estimate of the dodo’s mass is presented based on the largest sample of dodo femora ever measured (n = 174). In order to do this, we have used the regression method and chosen our variables based on biological, mathematical and physical arguments. The results indicate that the mean mass of the dodo was circa 12 kg, which is approximately five times as heavy as the largest living Columbidae (pigeons and doves), the clade to which the dodo belongs.

Concepts: Bird, Columbidae, Mauritius, Columbiformes, Dodo, Raphinae, Rodrigues Solitaire, Nicobar Pigeon

6

The closely related and extinct Dodo (Raphus cucullatus) and Rodrigues Solitaire (Pezophaps solitaria), both in the subfamily Raphinae, are members of a clade of morphologically very diverse pigeons. Genetic analyses have revealed that the Nicobar Pigeon (Caloenas nicobarica) is the closest living relative of these birds, thereby highlighting their ancestors' remarkable migration and morphological evolution. The Spotted Green Pigeon (Caloenas maculata) was described in 1783 and showed some similarities to the Nicobar Pigeon. Soon however the taxon fell into obscurity, as it was regarded as simply an abnormal form of the Nicobar Pigeon. The relationship between both taxa has occasionally been questioned, leading some ornithologists to suggest that the two may in fact be different taxa. Today only one of the original two specimens survives and nothing is known about the origin of the taxon. Due to its potential close relationship, the Spotted Green Pigeon may hold clues to the historical migration, isolation and morphological evolution of the Dodo and its kindred.

Concepts: Columbidae, Columbiformes, Dodo, Raphinae, Rodrigues Solitaire, Nicobar Pigeon, RĂ©union Sacred Ibis, Island gigantism

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Abstract Trichomonas gallinae, the cause of avian trichomonosis, is most commonly found in the order Columbiformes. Racing pigeons are often treated preventively with nitro-imidazoles which could result in the emergence of resistant isolates. These isolates can be a threat to wildlife when exchange of isolates would occur. The sequence type of 16 T. gallinae isolates obtained from racing pigeons and 15 isolates from wild pigeons was determined based on the ITS1/5.8S rRNA/ITS2 region sequence. The resistance profiles of these isolates against five different nitro-imidazoles (metronidazole, dimetridazole, ronidazole, tinidazole and carnidazole) were determined. Two different Trichomonas sequence types were isolated. Sequence type A isolates were recovered from racing and wild pigeons, in contrast to sequence type B which was only isolated from wild pigeons. Isolates with sequence type B were all susceptible to the tested nitro-imidazoles, except for tinidazole-resistance in 3 isolates. Resistance to the nitro-imidazoles was observed more frequently in isolates obtained from racing pigeons than from wild pigeons, with most isolates belonging to sequence type A. A higher percentage of the sequence types A isolated from racing pigeons, in comparison with those isolated from the wild pigeons, were resistant to the nitro-imidazoles and displayed higher MLC values. Two isolates belonging to sequence type A, 1 recovered from a racing pigeon and 1 from a wild pigeon, displayed a similar resistance pattern, suggesting a potential exchange of resistant isolates between racing pigeons and wild pigeons.

Concepts: Bird, Columbidae, Rock Pigeon, Columbiformes, Dodo, Raphinae, Rodrigues Solitaire