A new fossil subspecies of booby (Aves, Sulidae: Papasula) from Mauritius and Rodrigues, Mascarene Islands, with notes on P. abbotti from Assumption Island.

A new subspecies of Papasula booby is described from fossil remains collected in the Mascarene Islands of Mauritius and Rodrigues, southwestern Indian Ocean. The Mascarene Booby Papasula abbotti nelsoni ssp. nov., larger than nominate Abbott's Booby P. a. abbotti from Christmas Island, northeast Indian Ocean, was approximately the same size as the extinct Hiva Oa Booby P. a. costelloi from the Marquesas in the Eastern Pacific. Mentioned in early accounts of Mauritius in 1668 and in 1725-26 and 1761 on Rodrigues, the Mascarene booby became extinct by the end of the 18th century. Members of another isolated but now extirpated population of Papasula abbotti from Assumption Island in the Seychelles Archipelago, the island from which the type specimen was collected, are identical to extant Christmas Island birds in size and colouration and discussed in detail herein.

A global analysis of avian island diversity-area relationships in the Anthropocene.

Research on island species-area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity-area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have 're-calibrated' the IDARs such that they resemble the historic period prior to recent extinctions.

Novel plant-frugivore network on Mauritius is unlikely to compensate for the extinction of seed dispersers.

Insular communities are particularly vulnerable to anthropogenic extinctions and introductions. Changes in composition of island frugivore communities may affect seed dispersal within the native plant community, risking ecological shifts and ultimately co-extinction cascades. Introduced species could potentially mitigate these risks by replacing ecological functions of extinct species, but conclusive evidence is lacking. Here, we investigate changes in plant-frugivore interactions involving frugivorous birds, mammals and reptiles in Mauritius, an oceanic island with an exceptionally well-specified frugivore community and well-described species introduction history. We demonstrate substantial losses of binary interaction partnerships (at the species level) resulting from native species extinctions, but also gains of equal numbers of novel interactions with introduced species, potentially supporting the idea that non-native species might compensate for lost seed dispersal. However, closer investigation of animal seed handling behaviour reveals that most interactions with seed dispersers are replaced by ecologically different interactions with seed predators. Therefore, restoration of seed dispersal functionality in this novel plant-frugivore community is unlikely.

A 14,000-year-old genome sheds light on the evolution and extinction of a Pleistocene vulture.

The New World Vulture [Coragyps] occidentalis (L. Miller, 1909) is one of many species that were extinct by the end of the Pleistocene. To understand its evolutionary history we sequenced the genome of a 14,000 year old [Coragyps] occidentalis found associated with megaherbivores in the Peruvian Andes. occidentalis has been viewed as the ancestor, or possibly sister, to the extant Black Vulture Coragyps atratus, but genomic data shows occidentalis to be deeply nested within the South American clade of atratus. Coragyps atratus inhabits lowlands, but the fossil record indicates that occidentalis mostly occupied high elevations. Our results suggest that occidentalis evolved from a population of atratus in southwestern South America that colonized the High Andes 300 to 400 kya. The morphological and morphometric differences between occidentalis and atratus may thus be explained by ecological diversification following from the natural selection imposed by this new and extreme, high elevation environment. The sudden evolution of a population with significantly larger body size and different anatomical proportions than atratus thus constitutes an example of punctuated evolution.

Eggs of extinct dwarf island emus retained large size.

Islands off southern Australia once harboured three subspecies of the mainland emu (Dromaius novaehollandiae), the smaller Tasmanian emu (D. n. diemenensis) and two dwarf emus, King Island emu (D. n. minor) and Kangaroo Island emu (D. n. baudinianus), which all became extinct rapidly after discovery by human settlers. Little was recorded about their life histories and only a few historical museum specimens exist, including a number of complete eggs from Tasmania and a unique egg from Kangaroo Island. Here, we present a detailed analysis of eggs of dwarf emus, including the first record of an almost complete specimen from King Island. Our results show that despite the reduction in size of all island emus, especially the King Island emu that averaged 44% smaller than mainland birds, the egg remained similar sized in linear measurements, but less in volume and mass, and seemingly had a slightly thinner eggshell. We provide possible reasons why these phenomena occurred.

Cranial evolution in the extinct Rodrigues Island owl Otus murivorus (Strigidae), associated with unexpected ecological adaptations.

Island birds that were victims of anthropic extinctions were often more specialist species, having evolved their most distinctive features in isolation, making the study of fossil insular birds most interesting. Here we studied a fossil cranium of the 'giant' extinct scops owl Otus murivorus from Rodrigues Island (Mascarene Islands, southwestern Indian Ocean), to determine any potential unique characters. The fossil and extant strigids were imaged through X-ray microtomography, providing 3D views of external and internal (endocast, inner ear) cranial structures. Geometric morphometrics and analyses of traditional measurements yielded new information about the Rodrigues owl's evolution and ecology. Otus murivorus exhibits a 2-tier "lag behind" phenomenon for cranium and brain evolution, both being proportionately small relative to increased body size. It also had a much more developed olfactory bulb than congeners, indicating an unexpectedly developed olfactory sense, suggesting a partial food scavenging habit. In addition, O. murivorus had the eyes placed more laterally than O. sunia, the species from which it was derived, probably a side effect of a small brain; rather terrestrial habits; probably relatively fearless behavior; and a less vertical posture (head less upright) than other owls (this in part an allometric effect of size increase). These evolutionary features, added to gigantism and wing reduction, make the extinct Rodrigues owl's evolution remarkable, and with multiple causes.

The Réunion Fody and Sonnerat's Shrew and the validity of scientifically naming animals described without physical types.

An essential requirement of the current edition of the International Code of Zoological Nomenclature (ICZN 1999) is to designate a holotype or syntypes for a species or subspecies newly described after 1999. Where specimens exist this makes sense (and is indeed essential), but is meaningless when describing a species-group taxon from an old illustration or written account in which specimens were not preserved or even necessarily taken at all. The naming of two species which one or both of us described post-1999 from old accounts without designating types has been singled out as invalid on this basis. As the revisers of the ICZN apparently did not anticipate further naming of taxa from old accounts, and thus allowed a logical paradox to arise, we strongly recommend that, in respect of descriptions from old accounts with no specimens, this rule be waived by a retrospective amendment, as it is likely that other similar cases exist, and it serves no-ones' interest to strike down otherwise properly described names on a pointless technicality. Prior to our proposed change in the Code, in this note Foudia delloni Cheke Hume sp. nov. (Aves: Passeriformes: Ploceidae), from Réunion Island, and Diplomesodon sonnerati Cheke sp. nov. (Mammalia: Soricomorpha: Soricidae), from southern India, are named anew using the same names and the original diagnoses.

A terrestrial vertebrate palaeontological review of Aldabra Atoll, Aldabra Group, Seychelles.

The Pleistocene vertebrate assemblage of Aldabra Atoll has been comparatively well studied. Three Upper Pleistocene fossil localities have been described yielding birds, reptiles and terrestrial molluscs. Those of Bassin Cabri and Bassin Lebine on Ile Picard are undated but must be in excess of 136,000 YBP, whereas Point Hodoul on Malabar Island is circa 100,000 YBP. Aldabra was seemingly completely submerged between deposition of the Ile Picard and Point Hodoul deposits, resulting in local faunal extinctions. Here we present the results of an ongoing study of fossil material collected on Ile Picard in 1987, which reveals a more diverse assemblage than previously realised. Notable discoveries are an Ardeola heron, three Procellariformes, tropic-bird Phaethon, gull Larus, rail Dryolimnas, harrier Circus and owl Tyto, plus evidence of recolonisation of the atoll by some seabirds, rail, harrier, owl, giant tortoises and lizards after the Ile Picard/Point Hodoul submergence event.

Dodo remains from an in situ context from Mare aux Songes, Mauritius.

Since 2005, excavations at Mare aux Songes, Mauritius, have revealed the presence of a very rich, ∼4,200-year-old fossil bone bed including dodo (Raphus cucullatus) bones and bone fragments. The recently excavated dodo assemblage comprises at least 17 individuals and is characterised by the presence of small and fragile skeletal elements, a dominance of leg elements and an absence of juveniles. The hydrology of the area suggests that dodos, like many other species, were probably lured to Mare aux Songes by the presence of freshwater during times of drought. The most likely scenario for the origin of the fossil deposit is that animals became trapped in the sediment in repeated miring events, which would favour the conservation of hindlimbs. Such a scenario is fully in accordance with the taphonomic characteristics of the bone assemblage.