Search publications of the members of the Royal Belgian institute of natural Sciences
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Editorial: Proceedings of the Conference on the Environmental Archaeology of European Cities (CEAEC)
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Dr Claude Massin (25/08/1948—04/09/2021), in Memoriam
- This contribution provides an overview of the scientific career of the late Dr Claude Massin (1948–2021), listing his scientific activities (academic career, participation to and organization of expeditions and scientific conferences, publications) as well as the taxa he described as new to science and the eponyms that were dedicated to him. The scientific career of Claude Massin is briefly sketched against the background of the personal family-life.
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On the rediscovery of Phalilus oberthuri (GUIGNOT, 1935) in New Caledonia (Coleoptera: Haliplidae)
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Morphometric Studies of the Sweet Potato Weevil, Cylas species-complex in Southern Ghana.
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Asilidae in restored heathland patches near Bruges: surprisingly species rich ! (Diptera; Asilidae)
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Insecten in de Swal in Koekelare, Deel 2 : Loopkevers van natte schrale graslanden.
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Field Intercomparison of Radiometer Measurements for Ocean Colour Validation
- A field intercomparison was conducted at the Acqua Alta Oceanographic Tower (AAOT) in the northern Adriatic Sea, from 9 to 19 July 2018 to assess differences in the accuracy of in- and above-water radiometer measurements used for the validation of ocean colour products. Ten measurement systems were compared. Prior to the intercomparison, the absolute radiometric calibration of all sensors was carried out using the same standards and methods at the same reference laboratory. Measurements were performed under clear sky conditions, relatively low sun zenith angles, moderately low sea state and on the same deployment platform and frame (except in-water systems). The weighted average of five above-water measurements was used as baseline reference for comparisons. For downwelling irradiance ( E d ), there was generally good agreement between sensors with differences of <6\% for most of the sensors over the spectral range 400 nm–665 nm. One sensor exhibited a systematic bias, of up to 11\%, due to poor cosine response. For sky radiance ( L s k y ) the spectrally averaged difference between optical systems was <2.5\% with a root mean square error (RMS) <0.01 mWm−2 nm−1 sr−1. For total above-water upwelling radiance ( L t ), the difference was <3.5\% with an RMS <0.009 mWm−2 nm−1 sr−1. For remote-sensing reflectance ( R r s ), the differences between above-water TriOS RAMSES were <3.5\% and <2.5\% at 443 and 560 nm, respectively, and were <7.5\% for some systems at 665 nm. Seabird-Hyperspectral Surface Acquisition System (HyperSAS) sensors were on average within 3.5\% at 443 nm, 1\% at 560 nm, and 3\% at 665 nm. The differences between the weighted mean of the above-water and in-water systems was <15.8\% across visible bands. A sensitivity analysis showed that E d accounted for the largest fraction of the variance in R r s , which suggests that minimizing the errors arising from this measurement is the most important variable in reducing the inter-group differences in R r s . The differences may also be due, in part, to using five of the above-water systems as a reference. To avoid this, in situ normalized water-leaving radiance ( L w n ) was therefore compared to AERONET-OC SeaPRiSM L w n as an alternative reference measurement. For the TriOS-RAMSES and Seabird-HyperSAS sensors the differences were similar across the visible spectra with 4.7\% and 4.9\%, respectively. The difference between SeaPRiSM L w n and two in-water systems at blue, green and red bands was 11.8\%. This was partly due to temporal and spatial differences in sampling between the in-water and above-water systems and possibly due to uncertainties in instrument self-shading for one of the in-water measurements.
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First Evaluation of PRISMA Level 1 Data for Water Applications
- This study presents a first assessment of the Top-Of-Atmosphere (TOA) radiances measured in the visible and near-infrared (VNIR) wavelengths from PRISMA (PRecursore IperSpettrale della Missione Applicativa), the new hyperspectral satellite sensor of the Italian Space Agency in orbit since March 2019. In particular, the radiometrically calibrated PRISMA Level 1 TOA radiances were compared to the TOA radiances simulated with a radiative transfer code, starting from in situ measurements of water reflectance. In situ data were obtained from a set of fixed position autonomous radiometers covering a wide range of water types, encompassing coastal and inland waters. A total of nine match-ups between PRISMA and in situ measurements distributed from July 2019 to June 2020 were analysed. Recognising the role of Sentinel-2 for inland and coastal waters applications, the TOA radiances measured from concurrent Sentinel-2 observations were added to the comparison. The results overall demonstrated that PRISMA VNIR sensor is providing TOA radiances with the same magnitude and shape of those in situ simulated (spectral angle difference, SA, between 0.80 and 3.39; root mean square difference, RMSD, between 0.98 and 4.76 [mW m−2 sr−1 nm−1]), with slightly larger differences at shorter wavelengths. The PRISMA TOA radiances were also found very similar to Sentinel-2 data (RMSD 3.78 [mW m−2 sr−1 nm−1]), and encourage a synergic use of both sensors for aquatic applications. Further analyses with a higher number of match-ups between PRISMA, in situ and Sentinel-2 data are however recommended to fully characterize the on-orbit calibration of PRISMA for its exploitation in aquatic ecosystem mapping.
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Two new Kukri Snake species (Colubridae: Oligodon) from the Nakhon Si Thammarat Mountain Range, and addition of O. ocellatus to the fauna of Thailand
- We describe two new Kukri snakes of the genus Oligodon from the Nakhon Si Thammarat Mountain Range, southern peninsular Thailand. Oligodon phangan sp. nov., endemic to Pha-Ngan Island, Surat Thani Province, is characterized by a maximal known SVL of 369.1 mm; 12 maxillary teeth, the posterior three enlarged; 17-17-15 dorsal scale rows; 163-166 ventrals; 33-42 divided subcaudals; a single anal; dorsal color brown with a pair of discreet paravertebral and lateral stripes; no dorsal or supracaudal bands, blotches or crossbars; background color of belly pinkish-orange; underside of tail immaculate. Oligodon promsombuti sp. nov., whose type-locality is Khao Phanom Wang, Surat Thani Province, is also found in Trang Province, and is characterized by a maximal known SVL of 552.7 mm; 12 maxillary teeth, the posterior three enlarged; 17-17-15 dorsal scale rows; 177 ventrals; 40 divided subcaudals; a single anal; deeply forked hemipenes lacking spines; dorsal color blackish brown with nearly indistinct paravertebral stripes; no dorsal or supracaudal blotches or crossbars; background color of belly ivory, heavily speckled with subrectangular blackish blotches. We tentatively allocate both new species to the informal Oligodon-cyclurus-group. They are the 5 th and 6 th Oligodon species endemic to Thailand. We add Oligodon ocellatus, so far known only from Cambodia, southern Laos and southern Vietnam, to the Thai fauna, based on a specimen from Chong Mek, Ubon Ratchathani Province.
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Conservation status of the world’s skinks (Scincidae): Taxonomic and geographic patterns in extinction risk
- Our knowledge of the conservation status of reptiles, the most diverse class of terrestrial vertebrates, has improved dramatically over the past decade, but still lags behind that of the other tetrapod groups. Here, we conduct the first comprehensive evaluation (~92% of the world’s ~1714 described species) of the conservation status of skinks (Scincidae), a speciose reptile family with a worldwide distribution. Using International Union for Conservation of Nature (IUCN) criteria, we report that ~20% of species are threatened with extinction, and nine species are Extinct or Extinct in the Wild. The highest levels of threat are evident in Madagascar and the Neotropics, and in the subfamilies Mabuyinae, Eugongylinae and Scincinae. The vast majority of threatened skink species were listed based primarily on their small geographic ranges (Criterion B, 83%; Criterion D2, 13%). Although the population trend of 42% of species was stable, 14% have declining populations. The key threats to skinks are habitat loss due to agriculture, invasive species, and biological resource use (e.g., hunting, timber harvesting). The distributions of 61% of species do not overlap with protected areas. Despite our improved knowledge of the conservation status of the world’s skinks, 8% of species remain to be assessed, and 14% are listed as Data Deficient. The conservation status of almost a quarter of the world’s skink species thus remains unknown. We use our updated knowledge of the conservation status of the group to develop and outline the priorities for the conservation assessment and management of the World's skink species.
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The Mont-des-Récollets section (N France): a key site for the Ypresian-Lutetian transition at mid-latitudes - reassessment of the boundary criterion for the base-Lutetian GSSP.
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Of dogs, wolves, and debate: A reply to Janssens et al. (2021)
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Night stalkers from above: A monograph of Toxicodryas tree snakes (Squamata: Colubridae) with descriptions of two new cryptic species from Central Africa
- The genus Toxicodryas, historically included with the renowned Australasian cat-eyed snakes of the colubrid genus Boiga, currently includes two widespread species (T. blandingii and T. pulverulenta) in western, central, and eastern Africa. We leverage findings from a recent phylogenomic and historical demographic analysis of this genus (based on 2848-4471 Rad-seq loci from across the genome), with robust sampling from throughout the ranges of both species, to define two additional taxonomic units, with species boundaries corresponding to river barriers. Additional morphometric data from scores of examined museum specimens and literature records bolster the recognition of these two new cryptic species. We hypothesize that T. blandingii occurs west of the confluence of the Congo and Ubangi rivers, whereas a cryptic new species that is found east of this biogeographic barrier has significantly higher numbers of ventral scale counts in both sexes, additional significant differences in several scale counts, and lower venom toxicity. Toxicodryas pulverulenta occurs west of the Niger Delta in West Africa, whereas a cryptic new species that is found east of this biogeographic barrier has significantly higher numbers of subcaudal scale counts in both sexes. A review of published information regarding morphological variation, ecology, natural history, habitat, and venom is summarized for these four Toxicodryas species.
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Karstic Landscapes Are Foci of Species Diversity in the World’s Third-Largest Vertebrate Genus Cyrtodactylus Gray, 1827 (Reptilia: Squamata; Gekkonidae)
- Karstic landscapes are immense reservoirs of biodiversity and range-restricted endemism. Nowhere is this more evident than in the world’s third-largest vertebrate genus Cyrtodactylus (Gekkonidae) which contains well over 300 species. A stochastic character mapping analysis of 10 different habitat preferences across a phylogeny containing 345 described and undescribed species recovered a karst habitat preference occurring in 25.0% of the species, whereas that of the other eight specific habitat preferences occurred in only 0.2–11.0% of the species. The tenth category—general habitat preference—occurred in 38.7% of the species and was the ancestral habitat preference for Cyrtodactylus and the ultimate origin of all other habitat preferences. This study echoes the results of a previous study illustrating that karstic landscapes are generators of species diversity within Cyrtodactylus and not simply “imperiled arks of biodiversity” serving as refugia for relics. Unfortunately, the immense financial returns of mineral extraction to developing nations largely outweighs concerns for biodiversity conservation, leaving approximately 99% of karstic landscapes with no legal protection. This study continues to underscore the urgent need for their appropriate management and conservation. Additionally, this analysis supports the monophyly of the recently proposed 31 species groups and adds one additional species group.
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A new cave-dwelling Gekko (Gekko) from Lopburi Province, central Thailand (Squamata, Gekkonidae)
- We describe Gekko pradapdao sp. nov. from Tham Khao Chan (Khao Chan Cave), Tha Luang District, Lopburi Province, in central Thailand. The new species, a member of the subgenus Gekko, differs from all currently recognized Gekko species by the following combination of morphological characters and pattern: maximal known snout-vent length of 127.1 mm, lack of contact between nostrils and rostral, 24–28 interorbital scales between supraciliaries, 89–91 scale rows around midbody, 16–18 dorsal tubercle rows at midbody, 30–34 ventral scale rows at midbody, 11–13 precloacal pores in males, a single postcloacal tubercle on each side of the base of the tail, 13–16 subdigital lamellae on 1st toe and 17–19 on 4th toe, no Y-shaped mark on head, non-banded dorsal pattern on a dark chocolate brown to black background, and a dark brown iris. Urgent actions should be taken to evaluate the conservation status of the new species.
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A new sandstone-dwelling leaf-toed gecko (Gekkonidae: Dixonius mekongensis) from the Thai-Lao border
- We describe Dixonius mekongensis sp. nov. from sandstone formations in Khong Chiam District, Ubon Ratchathani Province, in extreme eastern Thailand along the Laotian border. The new species differs from all currently recognized Dixonius by the following combination of morphological characters and pattern: maximal known snout-vent length of 51.2 mm; 16 longitudinal rows of dorsal tubercles; 32 to 34 paravertebral scales; 22 to 24 longitudinal rows of ventral scales across the abdomen; seven precloacal pores in males, no pores in females; a marked canthal stripe; and a spotted to uniform dorsal pattern. This description brings the number of Dixonius species to 13, with six species endemic to Thailand.
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A new karst-dwelling, colorful pitviper (Viperidae: Trimeresurus) from northern Peninsular Thailand
- We describe a colorful and distinctively patterned, karst-dwelling pitviper, Trimeresurus kuiburi sp. nov., from the isolated, coastal massif of Khao Sam Roi Yot in Kui Buri District, Prachuap Khiri Khan Province, in northern Peninsular Thailand. The new species, member of the ‘Cryptelytrops group’ sensu Malhotra & Thorpe (2004) and morphologically and genetically allied to Trimeresurus kanburiensis and T. venustus, differs from all pitviper taxa by a combination of red/purple bands on a green dorsum; a white concave suborbital stripe in males (straight and less visible in females); white, spaced vertebral dots in males (absent in females); pale green belly lacking dark dots or stripe on the lateral sides of the ventrals; partially fused first supralabial and nasal scale; 19 dorsal scale rows at midbody; 164–171 ventrals; 63–65 subcaudals in males, 51–53 in females; maximal known SVL of 451 mm; and long, papillose hemipenes.
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Diversity, threats and conservation of western and central African amphibians (Senegal, The Gambia, Guinea Bissau, Mali, Guinea, Sierra Leone, Liberia, Ivory Coast, Burkina Faso, Ghana, Togo, Benin, Nigeria, Niger, Cameroon, Gabon, São Tome & Principe, Eq
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Miscellanea Herpetologica Gabonica XVII
- We present new Gabonese locality records, ecological or morphological data for Pelusios castaneus (Pelomedusidae), Kinixys erosa (Testudinidae), Osteolaemus tetraspis (Crocodylidae), Agama agama (Agamidae), Monopeltis galeata (Amphisbaenidae), Feylinia currori, Trachylepis polytropis (Scincidae), Varanus ornatus (Varanidae), Philothamnus hughesi, Rhamnophis batesii, Toxicodryas adamantea and T. blandingii (Colubridae), Dendroaspis jamesoni jamesoni (Elapidae), Bothrophthalmus brunneus, Limaformosa guirali and L. savorgnani (Lamprophiidae), Atheris squamigera and Bitis nasicornis (Viperidae). One snake species each is newly recorded from Pongara National Park and Nyanga Province, and two each from Batéké Plateau National Park and Haut-Ogooué Province. We refer all records of Toxicodryas pulverulenta from Gabon to T. adamantea. We discuss the use of camera traps for monitoring reptiles in Gabon based on the results of extensive camera trap surveys. We provide geographic coordinates for selected localities mentioned in MHG III–VI.
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Biodiversity, Biogeography and Nature Conservation in Wallacea and New Guinea. Volume IV
