Osteology Supports a Stem-Galliform Affinity for the Giant Extinct Flightless Bird Sylviornis neocaledoniae (Sylviornithidae,Galloanseres)

The giant flightless bird Sylviornis neocaledoniae (Aves: Sylviornithidae) existed on La Grande Terre and Ile des Pins, New Caledonia, until the late Holocene when it went extinct shortly after human arrival on these islands. The species was generally considered to be a megapode (Megapodiidae) until the family Sylviornithidae was erected for it in 2005 to reflect multiple cranial autapomorphies. However, despite thousands of bones having been reported for this unique and enigmatic taxon, the postcranial anatomy has remained largely unknown. We rectify this deficiency and describe the postcranial skeleton of S. neocaledoniae based on ~600 fossils and use data from this and its cranial anatomy to make a comprehensive assessment of its phylogenetic affinities. Sylviornis neocaledoniae is found to be a stem galliform, distant from megapodiids, and the sister taxon to the extinct flightless Megavitiornis altirostris from Fiji, which we transfer to the family Sylviornithidae. These two species form the sister group to extant crown-group galliforms. Several other fossil galloanseres also included in the phylogenetic analysis reveal novel hypotheses of their relationships as follows: Dromornis planei (Dromornithidae) is recovered as a stem galliform rather than a stem anseriform; Presbyornis pervetus (Presbyornithidae) is the sister group to Anseranatidae, not to Anatidae; Vegavis iaai is a crown anseriform but remains unresolved relative to Presbyornis pervetus, Anseranatidae and Anatidae. Sylviornis neocaledoniae was reconstructed herein to be 0.8 m tall in a resting stance and weigh 27–34 kg. The postcranial anatomy of S. neocaledoniae shows no indication of the specialised adaptation to digging seen in megapodiids, with for example, its ungual morphology differing little from that of chicken Gallus gallus. These observations and its phylogenetic placement as stem galliforms makes it improbable that this species employed ectothermic incubation or was a mound-builder. Sylviornis neocaledoniae can therefore be excluded as the constructor of tumuli in New Caledonia.     

A new species of Late Pleistocene rail (Aves: Rallidae) from Abaco, the Bahamas

We describe a new species of rail from the Sawmill Sink blue hole on Abaco Island in the northern Bahamas. Known from abundant, beautifully preserved Late Pleistocene fossils, Rallus cyanocavi sp. nov. was a medium-sized, flightless species that probably was endemic to the Little Bahama Bank, which is a carbonate platform surrounded by deeper water. We are uncertain whether R. cyanocavi survived into the Holocene, when higher sea levels transformed the Little Bahama Bank from a single large, Late Pleistocene island (ca. 12000 km²) to the scattering of smaller islands seen today, the largest of which is Abaco (1681 km²). Fossils of additional extinct, flightless species of Rallus probably await discovery on some of the 21 other carbonate banks that span the Bahamian Archipelago.     

Endocranial Anatomy of the Charadriiformes: Sensory System Variation and the Evolution of Wing-Propelled Diving

Just as skeletal characteristics provide clues regarding behavior of extinct vertebrates, phylogenetically-informed evaluation of endocranial morphology facilitates comparisons among extinct taxa and extant taxa with known behavioral characteristics. Previous research has established that endocranial morphology varies across Aves; however, variation of those systems among closely related species remains largely unexplored. The Charadriiformes (shorebirds and allies) are an ecologically diverse clade with a comparatively rich fossil record, and therefore, are well suited for investigating interspecies variation, and potential links between endocranial morphology, phylogeny, ecology and other life history attributes. Endocranial endocasts were rendered from high resolution X-ray computed tomography data for 17 charadriiforms (15 extant and two flightless extinct species). Evaluation of endocranial character state changes on a phylogeny for Charadriiformes resulted in identification of characters that vary in taxa with distinct feeding and locomotor ecologies. In comparison with all other charadriiforms, stem and crown clade wing-propelled diving Pan-Alcidae displayed compressed semicircular canals, and indistinct occipital sinuses and cerebellar fissures. Flightless wing-propelled divers have relatively smaller brains for their body mass and smaller optic lobes than volant pan-alcids. Observed differences between volant and flightless wing-propelled sister taxa are striking given that flightless pan-alcids continue to rely on the flight stroke for underwater propulsion. Additionally, the brain of the Black Skimmer Rynchops niger, a taxon with a unique feeding ecology that involves continuous forward aerial motion and touch-based prey detection used both at day and night, is discovered to be unlike that of any other sampled charadriiform in having an extremely large wulst as well as a small optic lobe and distinct occipital sinus. Notably, the differences between the Black Skimmer and other charadriiforms are more pronounced than between wing-propelled divers and other charadriiforms. Finally, aspects of endosseous labyrinth morphology are remarkably similar between divers and non-divers, and may deserve further evaluation.     

Virtual Reconstruction and Prey Size Preference in the Mid Cenozoic Thylacinid,Nimbacinus dicksoni (Thylacinidae,Marsupialia)

Thylacinidae is an extinct family of Australian and New Guinean marsupial carnivores, comprizing 12 known species, the oldest of which are late Oligocene (∼24 Ma) in age. Except for the recently extinct thylacine (Thylacinus cynocephalus), most are known from fragmentary craniodental material only, limiting the scope of biomechanical and ecological studies. However, a particularly well-preserved skull of the fossil species Nimbacinus dicksoni, has been recovered from middle Miocene (∼16-11.6 Ma) deposits in the Riversleigh World Heritage Area, northwestern Queensland. Here, we ask whether N. dicksoni was more similar to its recently extinct relative or to several large living marsupials in a key aspect of feeding ecology, i.e., was N. dicksoni a relatively small or large prey specialist. To address this question we have digitally reconstructed its skull and applied three-dimensional Finite Element Analysis to compare its mechanical performance with that of three extant marsupial carnivores and T. cynocephalus. Under loadings adjusted for differences in size that simulated forces generated by both jaw closing musculature and struggling prey, we found that stress distributions and magnitudes in the skull of N. dicksoni were more similar to those of the living spotted-tailed quoll (Dasyurus maculatus) than to its recently extinct relative. Considering the Finite Element Analysis results and dental morphology, we predict that N. dicksoni likely occupied a broadly similar ecological niche to that of D. maculatus, and was likely capable of hunting vertebrate prey that may have exceeded its own body mass.     

A new species of recently extinct rice rat (Megalomys) from Barbados

Recently extinct insular populations of oryzomyine rice rats (Cricetidae: Sigmodontinae) are known from across the Lesser Antilles, but most remain undescribed. Historical records of a possible now-extinct endemic rodent from Barbados are supported by presence of oryzomyine remains in Late Quaternary sites on the island, including several pre-Columbian Holocene archaeological sites. The Barbados oryzomyine is described as Megalomys georginae sp. nov., and is most closely related to species from the nearby islands of Martinique and St. Lucia, M. desmarestii and M. luciae. These species all display a zygomatic plate with its posterior margin level with the alveolus of M1, a divided anterocone on M1, and distinct anterolophids and metaflexids on m2 and m3, and are recovered as a monophyletic clade in morphological-molecular and morphology-only analyses. The new species differs from other Megalomys species in having the labial accessory root of M1 absent, a reduced anteromedian flexus on M1, two roots on m2 and m3, a supratrochlear foramen on the humerus, and in its much smaller body size. Other extinct Caribbean oryzomyines are not recovered in a monophyletic clade with Megalomys.     

A refined model of body mass and population density in flightless birds reconciles extreme bimodal population estimates for extinct moa

Flightless birds were once the largest and heaviest terrestrial fauna on many archipelagos around the world. Robust approaches for estimating their population parameters are essential for understanding prehistoric insular ecosystems and extinction processes. Body mass and population density are negatively related for extant flightless bird species, providing a method for quantifying densities and population sizes of extinct flightless species. Here we assemble an updated global data set of body mass and population densities for extant flightless birds and estimate the relationship between these variables. We use generalised least squares models that account for phylogenetic relatedness and incorporate the effects of limiting factors (e.g. habitat suitability) on population density. We demonstrate the applicability of this allometric relationship to extinct species by estimating densities for each of the nine species of moa (Dinornithiformes) and generating a combined spatially explicit map of total moa density across New Zealand. To compare our density estimates with those previously published, we summed individual species' abundances to generate a mean national density of 2.02–9.66 birds km⁻² for low- and high-density scenarios, respectively. Our results reconcile the extreme bimodality of previous estimates (< 2 birds km⁻² and > 10 birds km⁻²) and are comparable to contemporary densities of large herbivorous wild mammals introduced into New Zealand about 150 yr ago. The revised moa density has little effect on the harvest rates required to bring about extinction within 150–200 yr, indicating that rapid extinction was an inevitable response to human hunting, irrespective of the initial population of moa.     

Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology

Extinctions and declines of large marine vertebrates have major ecological impacts and are of critical concern in marine environments. The Caribbean monk seal, Monachus tropicalis, last definitively reported in 1952, was one of the few marine mammal species to become extinct in historical times. Despite its importance for understanding the evolutionary biogeography of southern phocids, the relationships of M. tropicalis to the two living species of critically endangered monk seals have not been resolved. In this study we present the first molecular data for M. tropicalis, derived from museum skins. Phylogenetic analysis of cytochrome b sequences indicates that M. tropicalis was more closely related to the Hawaiian rather than the Mediterranean monk seal. Divergence time estimation implicates the formation of the Panamanian Isthmus in the speciation of Caribbean and Hawaiian monk seals. Molecular, morphological and temporal divergence between the Mediterranean and “New World monk seals” (Hawaiian and Caribbean) is profound, equivalent to or greater than between sister genera of phocids. As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus. The two genera of extant monk seals (Monachus and Neomonachus) represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.     

Unexpected visitors: flightless beetles in window traps

Ancient woodlands are highly important for biodiversity. Flightless beetles and window traps may first appear to be incompatible as a study group and a study method. Little is known about the actual capability of window traps in monitoring of entire forest arthropod communities. We try to determine the possibility of using window traps (designed as tree traps) as an additional method to trap flightless beetles of the genera Carabus (Carabidae), Acalles and Trachodes (Curculionidae), as vulnerable representatives of wildlife forest fauna with high conservation value. From the environmental point of view, the occurrence of the studied flightless beetles was significantly more influenced by altitude than tree species as the studied environmental variables. Several beetles also showed positive significant species to species relationships during their observed phenological activity. Our results showed that the studied flightless beetles may reappear in secondary forests if these reach their optimal structure. On the other hand, they may be sensitive to large scale disturbances and not only to those caused by commercial forestry. The results also showed that window traps designed as tree traps could be used to successfully trap assemblages of forest fauna including flightless species.     

Comparative Biogeography of Grasshoppers (Orthoptera: Acrididae) in North America and Siberia: Applications to the Conservation of Biodiversity

The objective of this study was to apply knowledge of holarctic grasshopper biogeography in representative, temperate ecosystems (Russia, South Siberia, Sayans region; 685,000km² and USA, Wyoming; 272,000km²) to develop a comparative basis for understanding and conserving insect biodiversity. Maps of species distributions and vegetation zones were digitized, and a Geographic Information System was used to identify habitats with the greatest biodiversity and to characterize this diversity as a function of selected attributes. With respect to subfamilies, the greatest differences were in cold, mesic zones, where gomphocerines and melanoplines were dominant in Sayans and Wyoming, respectively. In terms of mobility, the Sayans has more flightless species and individuals, with the taiga supporting the greatest frequency of flightless acridids in both countries. With regard to feeding types, the diversity and richness of graminivores and forbivores were similar in the two regions, but mixed feeders were much more frequent in Wyoming. In the Sayans and Wyoming, pest species were most common in boreal and prairie zones, respectively. Ecoregions with a high diversity of pests also supported a high diversity of rare species. Shrub and desert zones supported many rare species in both countries. Thus, in terms of conservation, the Sayans' acridofauna appears to be at greater risk in terms of ecological vulnerability; acridid biodiversity is dispersed among habitats, with high frequencies of flightless and oligophagous species. The acridofauna of Wyoming could be conserved in fewer habitats than in the Sayans, but these habitats are subject to considerable human disturbance.     

Revision of Late Pleistocene and Holocene Galliformes Fauna from the Crimean Mountains

The Late Pleistocene and Holocene Galliformes faunas from the Crimean Mountains included seven species of birds belonging to the families Phasianidae and Tetraonidae: Phasianus colchicus, Alectoris chukar, Perdix perdix, Coturnix coturnix, Lyrurus tetrix, Lagopus mutus, and Lagopus lagopus. The habitation of Gallus representatives in the Crimea in the Late Pleistocene has not been confirmed. Representatives of the family Phasianidae were present in the Crimean fauna at least for most of the Late Pleistocene. All of them survived until the Late Holocene. Pheasants became extinct around the eighteenth century, and the rock partridge seems to have disappeared only in the first half of the twentieth century. The species were restored in the Crimea in the second half of the twentieth century. Gray partridges were common resident birds of the Crimean Mountains throughout the Late Pleistocene and Holocene. Quail was not a numerous breeding species of the Crimean Mountains at the same time, but mass migration of this species through the Crimea appeared only at the end of the Late Pleistocene and evolved over the Holocene warming. Species of Tetraonidae appeared in the fauna of the Crimea long before the beginning of the cold-phase maximum of the last glaciations but no later than 28000 years ago and became extinct in the Early Holocene warming but no later than 9000 years ago.     

Invader or resident? Ancient-DNA reveals rapid species turnover in New Zealand little penguins

The expansion of humans into previously unoccupied parts of the globe is thought to have driven the decline and extinction of numerous vertebrate species. In New Zealand, human settlement in the late thirteenth century AD led to the rapid demise of a distinctive vertebrate fauna, and also a number of ''turnover'' events where extinct lineages were subsequently replaced by closely related taxa. The recent genetic detection of an Australian little penguin (Eudyptula novaehollandiae) in southeastern New Zealand may potentially represent an additional ‘cryptic’ invasion. Here we use ancient-DNA (aDNA) analysis and radiocarbon dating of pre-human, archaeological and historical Eudyptula remains to reveal that the arrival of E. novaehollandiae in New Zealand probably occurred between AD 1500 and 1900, following the anthropogenic decline of its sister taxon, the endemic Eudyptula minor. This rapid turnover event, revealed by aDNA, suggests that native species decline can be masked by invasive taxa, and highlights the potential for human-mediated biodiversity shifts.     

The recent fossil turtle record of the central plain of Thailand reveals local extinctions

With more than 50 extant turtle species, Southeast Asia is currently a hotspot of turtle biodiversity. However, the distribution areas of most species are decreasing as a consequence of human activities. The causes of this decline are multiple: habitat and natural resources destruction, introduction of invasive species, hunting, etc. Historical data are however still lacking for a detailed understanding of that regional trend as well as for forecasting its evolution in the future. Indeed, while oral testimonies and text data can provide a rather good appreciation of the decline of biodiversity over the last few decades; nothing is known about the dynamic of turtle biodiversity over the Holocene. This lack of data is especially damaging in area where human activities are interacting for a long time with the wild fauna, as the central plain of Thailand, which is now dominated by agricultural landscape. In order to solve these issues, we investigated five Holocene localities in Thai central plain which provided assemblages of turtle remains ranging from Neolithic to Dvaravati periods (4000 to 1000 BP). The studied archaeological assemblages showed a very high species richness. Species such as Malayemys macrocephala, Cuora amboinensis, Heosemys annandalii, Heosemys grandis, Siebenrockiella crassicolis, Amyda ornata were among the most abundant. We also found several plates and a cranial material belonging to a species of the genus Batagur and tortoise remains including Indotestudo elongata and a few plates belonging to the genus Geochelone. The Batagur and Geochelone genera are absent from living turtle assemblages in the central plain but are present in Myanmar, Cambodia, Indonesia or Southern Thailand for Batagur and far in the West for Geochelone (Myanmar) respectively. Batagur is usually found in coastal areas and its disappearance from central plain is interpreted as resulting from the destruction of a fragile habitat and possibly from the rapid geomorphological evolution of the Chao-Phraya deltaic plain, the disappearance of tortoises could result from deforestation. Cutting traces showed that most turtles were used as food resources at these times, suggesting that turtle hunting was a common practise. Furthermore, occurrence of holes in the margin of the carapace of specimens from Kheed Khin (Saraburi Province) and Promthin Tai (Lopburi Province) suggests that turtles were sometimes kept captive alive or transported. This study shows that investigation of recent fossil localities allows for a better understanding of the role of past human populations in the alteration of the biodiversity through time, and for a more accurate estimation of the rates of species extinction.     

Stasis and turnover in small shearwaters on Bermuda over the last 400 000 years (Aves: Procellariidae: Puffinus lherminieri group)

The extinct species Puffinus parvus Shufeldt of Bermuda is shown to be synonymous with the living taxon Puffinus boydi of the Cape Verde islands. This species occurred on Bermuda throughout the last 400 000 years, during both glacial and interglacial intervals, and into the Holocene up until the arrival of humans when introduced predators evidently caused its extirpation. Subsequently, the island was colonized briefly by the Caribbean species Puffinus lherminieri, which in turn was extirpated from the island in the 20th Century. The indications are that P. boydi successfully outcompeted P. lherminieri on Bermuda until it was removed through human agency, thus closely paralleling the situation documented for two species of Megadyptes penguins in New Zealand. Thus P. lherminieri and P. boydi have long functioned as biological species and should be considered as full species along with the cold‐water species Puffinus baroli of the North Atlantic. Restoration efforts for small shearwaters on Bermuda should now focus on P. boydi rather than P. lherminieri. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 699–707.     

The role of a local rediscovery in the evaluation of the conservation status of a plant species: Testing the hypothesis of the biodiversity knowledge gap

Although habitat destruction and the introduction of exotic species are causing the extinction of many native species, the number of extinct species that are then rediscovered is surprising. However, before searching for meaning of rediscoveries, we should distinguish between a false and a true rediscovery to avoid the interpretation of changes in biodiversity knowledge as changes in the efforts to conserve biodiversity. Here, we proposed the hypothesis of the biodiversity knowledge gap and a conceptual scheme to test this hypothesis, discussing how to deal with the rediscovery of a putatively extinct species. In this paper, we dealt with the local rediscovery of the plant Neptunia pubescens Benth. (Fabaceae), hypothesizing that if its local rediscovery is a case of the biodiversity knowledge gap (false rediscovery), its conservation status will change. Furthermore, we provided taxonomic data, geographic coordinates and figures as support for its local rediscovery, as well as some considerations about the implications for the conservation of N. pubescens.     

More than One Way of Being a Moa: Differences in Leg Bone Robustness Map Divergent Evolutionary Trajectories in Dinornithidae and Emeidae (Dinornithiformes)

The extinct moa of New Zealand included three families (Megalapterygidae; Dinornithidae; Emeidae) of flightless palaeognath bird, ranging in mass from <15 kg to >200 kg. They are perceived to have evolved extremely robust leg bones, yet current estimates of body mass have very wide confidence intervals. Without reliable estimators of mass, the extent to which dinornithid and emeid hindlimbs were more robust than modern species remains unclear. Using the convex hull volumetric-based method on CT-scanned skeletons, we estimate the mass of a female Dinornis robustus (Dinornithidae) at 196 kg (range 155–245 kg) and of a female Pachyornis australis (Emeidae) as 50 kg (range 33–68 kg). Finite element analysis of CT-scanned femora and tibiotarsi of two moa and six species of modern palaeognath showed that P. australis experienced the lowest values for stress under all loading conditions, confirming it to be highly robust. In contrast, stress values in the femur of D. robustus were similar to those of modern flightless birds, whereas the tibiotarsus experienced the highest level of stress of any palaeognath. We consider that these two families of Dinornithiformes diverged in their biomechanical responses to selection for robustness and mobility, and exaggerated hindlimb strength was not the only successful evolutionary pathway.     

Multiple transgressions of Wallace's Line explain diversity of flightless Trigonopterus weevils on Bali

The fauna of Bali, situated immediately west of Wallace''s Line, is supposedly of recent Javanese origin and characterized by low levels of endemicity. In flightless Trigonopterus weevils, however, we find 100% endemism for the eight species here reported for Bali. Phylogeographic analyses show extensive in situ differentiation, including a local radiation of five species. A comprehensive molecular phylogeny and ancestral area reconstruction of Indo-Malayan–Melanesian species reveals a complex colonization pattern, where the three Balinese lineages all arrived from the East, i.e. all of them transgressed Wallace''s Line. Although East Java possesses a rich fauna of Trigonopterus, no exchange can be observed with Bali. We assert that the biogeographic picture of Bali has been dominated by the influx of mobile organisms from Java, but different relationships may be discovered when flightless invertebrates are studied. Our results highlight the importance of in-depth analyses of spatial patterns of biodiversity.     

Flightlessness affects cranial morphology in birds

Flightless birds belonging to phylogenetically distant clades share several morphological features in the pectoral and pelvic apparatus. There are indications that skull morphology is also influenced by flightlessness. In this study we used a large number of flightless species to test whether flightlessness in modern birds does indeed affect cranial morphology. Discriminant analyses and variation partitioning show evidence for a relationship between skull morphology and the flightless condition in birds. A possible explanation for the change in cranial morphology can be linked to the reduced selective force for light-weight skulls in flightless birds. This makes an increase in muscle mass, and therefore an enlargement of muscle insertion areas on the skull, possible. We also compared the ontogenetic trajectory of Gallus with the adult morphology of a sample of flightless species to see whether the apomorphic features characterizing the skull of flightless birds share the same developmental basis, which would indicate convergent evolution by parallelism. Skull morphology (expressed as principal component scores) of palaeognathous flightless birds (ratites) is dissimilar (higher scores) to juvenile stages of the chicken and therefore seem peramorphic (overdeveloped). Principal component scores of adult neognathous flightless birds fall within the range of chicken development, so no clear conclusions about the ontogenetic trajectories leading to their sturdier skull morphology could be drawn.     

First records and potential palaeoecological significance of Dianella (Xanthorrhoeaceae), an extinct representative of the native flora of Rapa Nui (Easter Island)

Easter Island, a remote island in the Pacific Ocean, is currently primarily covered by grasslands, but palaeoecological studies have shown the former presence of different vegetation. Much of its original biota has been removed during the last two millennia, most likely by human activities, and little is known about the native flora. Macrofossil and pollen analyses of a sediment core from the Raraku crater lake have revealed the occurrence of a plant that is currently extinct from the island: Dianella cf. intermedia/adenanthera (Xanthorrhoeaceae), which grew and disappeared at the Raraku site long before human arrival. The occurrence of Dianella within the Raraku sedimentary sequence (between 9.4 and 5.4 cal. kyr b.p.) could have been linked to the existence of favorable palaeoenvironmental conditions (peatland rather than the present-day lacustrine environment) during the early to mid Holocene. This finding contributes new knowledge about indigenous plant diversity on Easter Island and reinforces the usefulness of further macrofossil and pollen analyses to identify native species on Easter Island and elsewhere.