156 research outputs found

    Recent range expansion of an intermediate host for animal schistosome parasites in the Indo-Australian Archipelago: phylogeography of the freshwater gastropod Indoplanorbis exustus in South and Southeast Asia

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    Background: The planorbid snail Indoplanorbis exustus is the sole intermediate host for the Schistosoma indicum species group, trematode parasites responsible for cattle schistosomiasis and human cercarial dermatitis. This freshwater snail is widely distributed in Southern Asia, ranging from Iran to China eastwards including India and from the southeastern Himalayas to Southeast Asia southwards. The veterinary and medical importance of this snail explains the interest in understanding its geographical distribution patterns and evolutionary history. In this study, we used a large and comprehensive sampling throughout Indo-Malaya, including specimens from South India and Indonesia, areas that have been formerly less studied. Results: The phylogenetic inference revealed five highly divergent clades (genetic distances among clades: 4.4–13.9%) that are morphologically indistinguishable, supporting the assumption that this presumed nominal species may represent a cryptic species complex. The species group may have originated in the humid subtropical plains of Nepal or in southern adjacent regions in the Early Miocene. The major cladogenetic events leading to the fives clades occurred successively from the Early Miocene to the Early Pleistocene, coinciding with major periods of monsoonal intensification associated with major regional paleogeographic events in the Miocene and repeated climate changes due to the Plio-Pleistocene climatic oscillations. Our coverage of the Indo-Australian Archipelago (IAA) highlights the presence of a single clade there. Contrary to expectations, an AMOVA did not reveal any population genetic structure among islands or along a widely recognised zoogeographical regional barrier, suggesting a recent colonisation independent of natural biogeographical constraints. Neutrality tests and mismatch distributions suggested a sudden demographic and spatial population expansion that could have occurred naturally in the Pleistocene or may possibly result of a modern colonisation triggered by anthropogenic activities. Conclusions: Even though Indoplanorbis is the main focus of this study, our findings may also have important implications for fully understanding its role in hosting digenetic trematodes. The existence of a cryptic species complex, the historical phylogeographical patterns and the recent range expansion in the IAA provide meaningful insights to the understanding and monitoring of the parasites potential spread. It brings a substantial contribution to veterinary and public health issues

    The complex evolutionary history and phylogeography of Caridina typus (Crustacea: Decapoda): long-distance dispersal and cryptic allopatric species

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    The evolutionary history of the old, diverse freshwater shrimp genus Caridina is still poorly understood, despite its vast distribution – from Africa to Polynesia. Here, we used nuclear and mitochondrial DNA to infer the phylogeographic and evolutionary history of C. typus, which is one of only four species distributed across the entire range of the genus. Despite this species’ potential for high levels of gene flow, questions have been raised regarding its phylogeographic structure and taxonomic status. We identified three distinct lineages that likely diverged in the Miocene. Molecular dating and ancestral range reconstructions are congruent with C. typus’ early dispersal to Africa, possibly mediated by the Miocene Indian Ocean Equatorial Jet, followed by back dispersal to Australasia after the Jet’s closure. Furthermore, several different species delimitation methods indicate each lineage represents a distinct (cryptic) species, contradicting current morphospecies delimitation of a single C. typus taxon. The evolutionary history of C. typus lineages is complex, in which ancient oceanic current systems and (currently unrecognised) speciation events preceded secondary sympatry of these cryptic species

    Two new species of crayfish of the genus Cherax from Indonesian New Guinea (Crustacea, Decapoda, Parastacidae)

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    Two new species of the genus Cherax are described and illustrated. Cherax mosessalossa sp. n., endemic to the Klademak Creek drainage in Sorong, in the western part of the Kepala Burung (Vogelkop) peninsula, West Papua, Indonesia, is described, figured and compared with its closest relatives, Cherax misolicus Holthuis, 1949 and Cherax warsamsonicus. The new species may be easily distinguished from both by the shape of the rostrum, the shape of the chelae, the presence of five cervical spines, the shape of the scaphocerite, and short scattered hairs on the carapace. Cherax alyciae sp. n., endemic to creeks in the Digul River drainage in the eastern part of the Boven Digoel Regency, Papua, Indonesia, is described, figured, and compared with its closest relative, Cherax peknyi Lukhaup & Herbert, 2008. The new species may be easily distinguished from Cherax peknyi by the shape of the chelae, presence of a soft patch on the chelae of the males, and colouration. A molecular phylogeny based on two mitochondrial gene fragments, 16S and COI, supports the morphology-based description of the two new species, which can also be clearly distinguished by sequence differences

    INDOBIOSYS – DNA BARCODING AS A TOOL FOR THE RAPID ASSESSMENT OF HYPERDIVERSE INSECT TAXA IN INDONESIA: A STATUS REPORT

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    A status report with preliminary results for the IndoBioSys project is presented and the impact of the project results for our knowledge of the Indonesian fauna is discussed. Using the REST API available on the Barcode of Life Data System we recover 21,153 public records (3,390 BINs) from Indonesia and compare against the 21,813 records (3,580 BINs) generated by the IndoBioSys project. From all IndoBioSys BINs, 3,366 (94%) are new to Indonesia. IndoBioSys is responsible for a BIN increase of 36.5% in Lepidoptera, 62.6% in Trichoptera, 986% in Coleoptera, and 1,086% in Hymenoptera. After two years of the IndoBioSys project, the Museum Zoologicum Bogoriense became the depository institution of 51.9% of Lepidoptera records, 95.8% of Coleoptera records, 97.6% of Hymenoptera records and 59.4% of Trichoptera records for Indonesia available on Barcode of Life Data System (BOLD). Now, with 55% of all Indonesian records available on BOLD, it is the most important depository for records of Indonesian genetic biodiversity, housing more than 23,000 new voucher specimens in their collections. Before IndoBioSys, the Museum Zoologicum Bogoriense was responsible for only 9% of all records available in the Barcode of Life Data System for Indonesia, showing the importance of those pipelines in empowering the local institutions in becoming the reference depository of the local fauna

    Disjunct distributions of freshwater snails testify to a central role of the Congo system in shaping biogeographical patterns in Africa

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    BACKGROUND: The formation of the East African Rift System has decisively influenced the distribution and evolution of tropical Africa´s biota by altering climate conditions, by creating basins for large long-lived lakes, and by affecting the catchment and drainage directions of river systems. However, it remains unclear how rifting affected the biogeographical patterns of freshwater biota through time on a continental scale, which is further complicated by the scarcity of molecular data from the largest African river system, the Congo. RESULTS: We study these biogeographical patterns using a fossil-calibrated multi-locus phylogeny of the gastropod family Viviparidae. This group allows reconstructing drainage patterns exceptionally well because it disperses very poorly in the absence of existing freshwater connections. Our phylogeny covers localities from major drainage basins of tropical Africa and reveals highly disjunct sister-group relationships between (a) the endemic viviparids of Lake Malawi and populations from the Middle Congo as well as between (b) the Victoria region and the Okavango/Upper Zambezi area. CONCLUSIONS: The current study testifies to repeated disruptions of the distribution of the Viviparidae during the formation of the East African Rift System, and to a central role of the Congo River system for the distribution of the continent´s freshwater fauna during the late Cenozoic. By integrating our results with previous findings on palaeohydrographical connections, we provide a spatially and temporarily explicit model of historical freshwater biogeography in tropical Africa. Finally, we review similarities and differences in patterns of vertebrate and invertebrate dispersal. Amongst others we argue that the closest relatives of present day viviparids in Lake Malawi are living in the Middle Congo River, thus shedding new light on the origin of the endemic fauna of this rift lake

    Taxonomy and Biogeography without frontiers – WhatsApp, Facebook and smartphone digital photography let citizen scientists in more remote localities step out of the dark

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    Taxonomy and biogeography can benefit from citizen scientists. The use of social networking and open access cooperative publishing can easily connect naturalists even in more remote areas with in-country scientists and institutions, as well as those abroad. This enables taxonomic efforts without frontiers and at the same time adequate benefit sharing measures. We present new distribution and habitat data for diving beetles of Bali island, Indonesia, as a proof of concept. The species Hydaticus luczonicus Aubé, 1838 and Eretes griseus (Fabricius, 1781) are reported from Bali for the first time. The total number of Dytiscidae species known from Bali is now 34

    DNA barcoding data release for Coleoptera from the Gunung Halimun canopy fogging workpackage of the Indonesian Biodiversity Information System (IndoBioSys) project

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    We present the results of a DNA barcoding pipeline that was established as part of the German-Indonesian IndobioSys project - Indonesian Biodiversity Information System. Our data release provides the first large-scale diversity assessment of Indonesian coleoptera obtained by canopy fogging. The project combined extensive fieldwork with databasing, DNA barcode based species delineation and the release of results in collaboration with Indonesian counterparts, aimed at supporting further analyses of the data. Canopy fogging on 28 trees was undertaken at two different sites, Cikaniki and Gunung Botol, in the south-eastern area of the Gunung Halimun-Salak National Park in West Java, Indonesia. In total, 7,447 specimens of Coleoptera were processed, of which 3,836 specimens produced DNA barcode sequences that were longer than 300 bp. A total of 3,750 specimens were assigned a Barcode Index Number (BIN), including 2,013 specimens from Cikaniki and 1,737 specimens from Gunung Botol. The 747 BINs, that were obtained, represented 39 families of Coleoptera. The distribution of specimens with BINs per tree was quite heterogeneous in both sites even in terms of the abundance of specimens or diversity of BINs. The specimen distribution per taxon was heterogeneous as well. Some 416 specimens could not be identified to family level, corresponding to 72 BINs that lack a family level identification. The data have shown a large heterogeneity in terms of abundance and distribution of BINs between sites, trees and families of Coleoptera. From the total of 747 BINs that were recovered, 421 (56%) are exclusive from a single tree. Although the two study sites were in close proximity and separated by a distance of only about five kilometres, the number of shared BINs between sites is low, with 81 of the 747 BINs. With this data release, we expect to shed some light on the largely hidden diversity in the canopy of tropical forests in Indonesia and elsewhere

    Can fractal dimensions objectivize gastropod shell morphometrics? A case study from Lake Lugu (SW China)

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    1. Morphometrics are fundamental for the analysis of size and shape in fossils, particularly because soft parts or DNA are rarely preserved and hard parts such as shells are commonly the only source of information. Geometric morphometrics, that is, landmark analysis, is well established for the description of shape but it exhibits a couple of shortcomings resulting from subjective choices during landmarking (number and position of landmarks) and from difficulties in resolving shape at the level of micro-sculpture. 2. With the aid of high-resolution 3D scanning technology and analyses of fractal dimensions, we test whether such shortcomings of linear and landmark morphometrics can be overcome. As a model group, we selected a clade of modern viviparid gastropods from Lake Lugu, with shells that show a high degree of sculptural variation. Linear and landmark analyses were applied to the same shells in order to establish the fractal dimensions. The genetic diversity of the gastropod clade was assessed. 3. The genetic results suggest that the gastropod clade represents a single species. The results of all morphometric methods applied are in line with the genetic results, which is that no specific morphotype could be delimited. Apart from this overall agreement, landmark and fractal dimension analyses do not correspond to each other but represent data sets with different information. Generally, the fractal dimension values quantify the roughness of the shell surface, the resolution of the 3D scans determining the level. In our approach, we captured the micro-sculpture but not the first-order sculptural elements, which explains that fractal dimension and landmark data are not in phase. 4. We can show that analyzing fractal dimensions of gastropod shells opens a window to more detailed information that can be considered in evolutionary and ecological contexts. We propose that using low-resolution 3D scans may successfully substitute landmark analyses because it overcomes the subjective landmarking. Analyses of 3D scans with higher resolution than used in this study will provide surface roughness information at the mineralogical level. We suggest that fractal dimension analyses of a combination of differently resolved 3D models will significantly improve the quality of shell morphometrics

    Paleo-Drainage Basin Connectivity Predicts Evolutionary Relationships across Three Southeast Asian Biodiversity Hotspots

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    Understanding factors driving diversity across biodiversity hotspots is critical for formulating conservation priorities in the face of ongoing and escalating environmental deterioration. While biodiversity hotspots encompass a small fraction of Earth's land surface, more than half the world's plants and two-thirds of terrestrial vertebrate species are endemic to these hotspots. Tropical Southeast (SE) Asia displays extraordinary species richness, encompassing four biodiversity hotspots, though disentangling multiple potential drivers of species richness is confounded by the region's dynamic geological and climatic history. Here, we use multilocus molecular genetic data from dense multispecies sampling of freshwater fishes across three biodiversity hotspots, to test the effect of Quaternary climate change and resulting drainage rearrangements on aquatic faunal diversification. While Cenozoic geological processes have clearly shaped evolutionary history in SE Asian halfbeak fishes, we show that paleo-drainage re-arrangements resulting from Quaternary climate change played a significant role in the spatiotemporal evolution of lowland aquatic taxa, and provide priorities for conservation efforts. [Freshwater; geology; halfbeak; island radiation; Miocene; Pleistocene; river; Southeast Asia.
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