scholarly journals Synoptic revision of the fern genus Elaphoglossum Schott ex J.Sm. (Dryopteridaceae) in Madagascar, with the description of 23 new taxa, all but one endemic

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10484
Author(s):  
Germinal Rouhan
Keyword(s):  
Indian Ocean ◽  
New Taxa ◽  
Western Indian Ocean ◽  
Field Studies ◽  
Morphological Description ◽  
Herbarium Specimens ◽  
New Taxon ◽  
La Réunion ◽  
Distribution Map ◽  
Original Illustrations

After 15 years of field studies in Madagascar, especially focused on the overlooked fern genus Elaphoglossum (Dryopteridaceae), a synoptic revision of the genus is here presented. Based on more than 2,600 herbarium specimens including collections over 200 years, Elaphoglossum is the second most diversified fern genus in Madagascar, with 52 species and three subspecies (with 76% of endemism). It is to be compared to the 34 species treated by Tardieu-Blot in 1960 for the “Flore de Madagascar et des Comores” or the 38 species listed by Roux in 2009 in the seminal “Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighboring islands”. The 55 taxa represent five out of seven existing generic sections (sect. Amygdalifolia and sect. Wrightiana being monotypic and Neotropical): sect. Lepidoglossa (29 spp. and three subspp.), sect. Elaphoglossum (17 spp.), sect. Setosa (3 spp.), sect. Squamipedia (2 spp.), and sect. Polytrichia (1 sp.). Distribution is given for each species and subspecies, and detailed for each island or archipelago in the Western Indian Ocean (La Réunion, Mauritius, Seychelles, and Comoros). Twenty species and three subspecies are newly described, all but one endemic to Madagascar: Elaphoglossum ambrense Rouhan, Elaphoglossum andohahelense Rouhan, Elaphoglossum anjanaharibense Rouhan, Elaphoglossum approximatum Rouhan, Elaphoglossum brachymischum Rouhan, Elaphoglossum cerussatum Tardieu subsp. brunneum Rouhan, Elaphoglossum coracinolepis Rouhan, Elaphoglossum desireanum Rouhan, Elaphoglossum glabricaule Rouhan, Elaphoglossum gladiifolium Rouhan, Elaphoglossum leucolepis (Baker) Krajina ex Tardieu subsp. nanolepis Rouhan, Elaphoglossum leucolepis (Baker) Krajina ex Tardieu subsp. nigricans Rouhan, Elaphoglossum longiacuminatum Rouhan, Elaphoglossum patriceanum Rouhan, Elaphoglossum perangustum Rouhan, Elaphoglossum prominentinervulum Rouhan, Elaphoglossum rakotondrainibeae Rouhan, Elaphoglossum repandum Rouhan, Elaphoglossum sabineanum Rouhan, Elaphoglossum sinensiumbrarum Rouhan, Elaphoglossum subglabricaule Rouhan, Elaphoglossum tsaratananense Rouhan, and Elaphoglossum viridicaule Rouhan. Morphological description, distribution map, and original illustrations are provided for each new taxon. Novel identification keys to the sections and all species from Madagascar are also presented.

scholarly journals Tomography of crust and lithosphere in the western Indian Ocean from noise cross-correlations of land and ocean bottom seismometers

2019 ◽  
Vol 219 (2) ◽  
pp. 924-944 ◽  
Author(s):  
Sarah Hable ◽  
Karin Sigloch ◽  
Eléonore Stutzmann ◽  
Sergey Kiselev ◽  
Guilhem Barruol
Keyword(s):  
Indian Ocean ◽  
Group Velocity ◽  
Western Indian Ocean ◽  
Spreading Ridge ◽  
Ocean Bottom ◽  
Depth Range ◽  
La Réunion ◽  
Velocity Measurements ◽  
Ocean Bottom Seismometers ◽  
Cross Correlations

SUMMARY We use seismic noise cross-correlations to obtain a 3-D tomography model of SV-wave velocities beneath the western Indian Ocean, in the depth range of the oceanic crust and uppermost mantle. The study area covers 2000 × 2000 km2 between Madagascar and the three spreading ridges of the Indian Ocean, centred on the volcanic hotspot of La Réunion. We use seismograms from 38 ocean bottom seismometers (OBSs) deployed by the RHUM-RUM project and 10 island stations on La Réunion, Madagascar, Mauritius, Rodrigues, and Tromelin. Phase cross-correlations are calculated for 1119 OBS-to-OBS, land-to-OBS, and land-to-land station pairs, and a phase-weighted stacking algorithm yields robust group velocity measurements in the period range of 3–50 s. We demonstrate that OBS correlations across large interstation distances of >2000 km are of sufficiently high quality for large-scale tomography of ocean basins. Many OBSs yielded similarly good group velocity measurements as land stations. Besides Rayleigh waves, the noise correlations contain a low-velocity wave type propagating at 0.8–1.5 km s−1 over distances exceeding 1000 km, presumably Scholte waves travelling through seafloor sediments. The 100 highest-quality group velocity curves are selected for tomographic inversion at crustal and lithospheric depths. The inversion is executed jointly with a data set of longer-period, Rayleigh-wave phase and group velocity measurements from earthquakes, which had previously yielded a 3-D model of Indian Ocean lithosphere and asthenosphere. Robust resolution tests and plausible structural findings in the upper 30 km validate the use of noise-derived OBS correlations for adding crustal structure to earthquake-derived tomography of the oceanic mantle. Relative to crustal reference model CRUST1.0, our new shear-velocity model tends to enhance both slow and fast anomalies. It reveals slow anomalies at 20 km depth beneath La Réunion, Mauritius, Rodrigues Ridge, Madagascar Rise, and beneath the Central Indian spreading ridge. These structures can clearly be associated with increased crustal thickness and/or volcanic activity. Locally thickened crust beneath La Réunion and Mauritius is probably related to magmatic underplating by the hotspot. In addition, these islands are characterized by a thickened lithosphere that may reflect the depleted, dehydrated mantle regions from which the crustal melts where sourced. Our tomography model is available as electronic supplement.

What is Muscari massayanum and what is not? Second species born of confusion: Muscari erzincanicum (Asparagaceae, Scilloideae), a new species from Turkey

Phytotaxa ◽  
2021 ◽  
Vol 487 (1) ◽  
pp. 41-55
Author(s):  
İSMAİL EKER
Keyword(s):  
New Species ◽  
Field Studies ◽  
Herbarium Specimens ◽  
New Taxon ◽  
Flora Of Turkey ◽  
Morphological Studies ◽  
Taxonomic Concept ◽  
Study Type ◽  
Seed Characteristics ◽  
A New Species

In the Flora of Turkey, the taxonomic concept of Muscari massayanum sensu Davis & Stuart was given based on five herbarium specimens and a photograph. In the original study, type location of the species was not specified, but its photograph and brief morphological features were included. In current study, herbarium samples given by Davis & Stuart under the description of the species in the Flora of Turkey were examined, and as a result of field studies conducted at the locations where these samples were collected, it was determined that the aforementioned description included M. massayanum, as well as the later published M. erdalii, and a new taxon yet to be named. As a result of comparative and detailed morphological studies to solve this confusion, a new species, Muscari erzincanicum (Asparagaceae) from Turkey, is described and illustrated. The new species is morphologically similar to M. massayanum and M. erdalii, but differs from both by the flower, fruit and seed characteristics.

Two new taxa of Festuca (Poaceae) from the southeastern Iberian Peninsula

Phytotaxa ◽  
2019 ◽  
Vol 395 (4) ◽  
pp. 251 ◽  
Author(s):  
GLORIA MARTÍNEZ-SAGARRA ◽  
JUAN A. DEVESA
Keyword(s):  
New Species ◽  
Iberian Peninsula ◽  
New Taxa ◽  
Leaf Anatomy ◽  
Related Species ◽  
Southern Spain ◽  
Herbarium Specimens ◽  
New Taxon ◽  
Differential Characters ◽  
A New Species

A new species, Festuca greuteri, from the southeast of the Iberian Peninsula (Spain) is described. The new taxon is recognised with two patterns of variation with the rank of subspecies: subsp. greuteri, widely distributed throughout the Baetic Mountains (Almería, Granada, Jaén and Málaga provinces, southern Spain), and subsp. camarolensis, located in the westernmost area of distribution, in the Sierra de Camarolos and Sierra del Jobo (Málaga province, southern Spain). This species belongs to Festuca sect. Festuca, and it had been overlooked or misidentified as F. segimonensis and F. longiauriculata, two species that are partially sympatric with it. Herbarium specimens and living plants were analysed, and noteworthy morphological and anatomical differences support their separation. A complete description is presented for the new species, and iconography and identification keys are provided together with information on leaf anatomy, ecology, phenology, and distribution. The new species is compared with the related species occurring in the southeastern Iberian Peninsula, and differential characters are discussed.

Gebiacantha sagamiensis, a new species of upogebiid shrimp (Crustacea: Decapoda: Gebiidea) from Sagami Bay, central Japan

Zootaxa ◽  
2017 ◽  
Vol 4263 (3) ◽  
Author(s):  
TOMOYUKI KOMAI
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
Taxonomic Status ◽  
Western Indian Ocean ◽  
La Réunion ◽  
Sagami Bay ◽  
Central Japan ◽  
Single Male ◽  
Male Specimen ◽  
A New Species

A new species of the upogebiid shrimp genus Gebiacantha Ngoc-Ho, 1989, G. sagamiensis, is described and illustrated on the basis of a single male specimen collected from Sagami Bay, central Japan, at depths of 101–106 m. It appears closest to G. reunionensis Ngoc-Ho, 1989, known only from La Réunion, western Indian Ocean, but the different shape of the pleomere 6 and the better developed armature of the pereopod 1 carpus distinguish the new species from G. reunionensis. Comments on the taxonomic status of Gebiacantha and Paragebicula Sakai, 2006, and on the generic assignment of the new species, are given.

scholarly journals Circulation around La Réunion and Mauritius islands in the south-western Indian Ocean: A modeling perspective

2014 ◽  
Vol 119 (3) ◽  
pp. 1957-1976 ◽  
Author(s):  
Stéphane Pous ◽  
Pascal Lazure ◽  
Gaël André ◽  
Franck Dumas ◽  
Issufo Halo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
La Réunion ◽  
The South

Biogeography, Community Structure and Diversity of Red Sea and Western Indian Ocean Butterflyfishes

1996 ◽  
Vol 76 (1) ◽  
pp. 223-228 ◽  
Author(s):  
David Righton ◽  
Jeremy Kemp ◽  
Rupert Ormond
Keyword(s):  
Indian Ocean ◽  
Red Sea ◽  
Western Indian Ocean ◽  
Field Studies ◽  
Microhabitat Use ◽  
Number Of Species ◽  
The North ◽  
Spatial Niche ◽  
Recent Origin ◽  
North And South

Patterns of variation in the assemblage structure of butterflyfishes (Chaetodontidae) of the Red Sea and western Indian Ocean have been compared. There is a lower number of species in the Red Sea, a high proportion of which are endemic to the region, both features that have been attributed to the relatively recent origin of the Red Sea. In the Red Sea overall mean abundance of butterflyfish is greatest in the central part, decreasing both to north and south. Several species present in the southern Red Sea are absent from the north. By contrast, most western Indian Ocean species are widely distributed within the Indo-West Pacific. Comparative field studies in the northern Red Sea (Egypt) and western Indian Ocean (Kenya) showed that mean number of species was higher in the western Indian Ocean, but mean density of butterflyfishes was higher in the Red Sea. In both areas diversity of butterflyfish was related to mean substrate diversity (the number of coral growth forms). Mean spatial niche breadth of butterflyfish species was much higher in the Red Sea than in the western Indian Ocean, whereas the extent of microhabitat use was higher in the western Indian Ocean. It is suggested that these differences may be related to the more recent evolution of the Red Sea fauna.

scholarly journals Performance report of the RHUM-RUM ocean bottom seismometer network around La Réunion, western Indian Ocean

2016 ◽  
Vol 41 ◽  
pp. 43-63 ◽  
Author(s):  
S. C. Stähler ◽  
K. Sigloch ◽  
K. Hosseini ◽  
W. C. Crawford ◽  
G. Barruol ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Network Performance ◽  
Western Indian Ocean ◽  
Primary Objective ◽  
Central Component ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
La Réunion ◽  
Ocean Bottom Seismometers ◽  
Performance Report

Abstract. RHUM-RUM is a German-French seismological experiment based on the sea floor surrounding the island of La Réunion, western Indian Ocean (Barruol and Sigloch, 2013). Its primary objective is to clarify the presence or absence of a mantle plume beneath the Reunion volcanic hotspot. RHUM-RUM's central component is a 13-month deployment (October 2012 to November 2013) of 57 broadband ocean bottom seismometers (OBS) and hydrophones over an area of 2000  ×  2000 km2 surrounding the hotspot. The array contained 48 wideband OBS from the German DEPAS pool and 9 broadband OBS from the French INSU pool. It is the largest deployment of DEPAS and INSU OBS so far, and the first joint experiment. This article reviews network performance and data quality: of the 57 stations, 46 and 53 yielded good seismometer and hydrophone recordings, respectively. The 19 751 total deployment days yielded 18 735 days of hydrophone recordings and 15 941 days of seismometer recordings, which are 94 and 80 % of the theoretically possible yields. The INSU seismic sensors stand away from their OBS frames, whereas the DEPAS sensors are integrated into their frames. At long periods (>  10 s), the DEPAS seismometers are affected by significantly stronger noise than the INSU seismometers. On the horizontal components, this can be explained by tilting of the frame and buoy assemblage, e.g. through the action of ocean-bottom currents, but in addition the DEPAS intruments are affected by significant self-noise at long periods, including on the vertical channels. By comparison, the INSU instruments are much quieter at periods >  30 s and hence better suited for long-period signals studies. The trade-off of the instrument design is that the integrated DEPAS setup is easier to deploy and recover, especially when large numbers of stations are involved. Additionally, the wideband sensor has only half the power consumption of the broadband INSU seismometers. For the first time, this article publishes response information of the DEPAS instruments, which is necessary for any project where true ground displacement is of interest. The data will become publicly available at the end of 2017.

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