While a growing body of modern phylogenetic research reveals that the Western Indochina represents a separate biogeographic subregion having a largely endemic freshwater fauna, the boundaries of this ...subregion are still unclear. We use freshwater mussels (Unionidae) as a model to reconstruct spatial patterns of freshwater biogeographic divides throughout Asia. Here, we present an updated freshwater biogeographic division of mainland Southeast Asia and describe 12 species and 4 genera of freshwater mussels new to science. We show that the Isthmus of Kra represents a significant southern biogeographic barrier between freshwater mussel faunas of the Western Indochina and Sundaland subregions, while the Indian and Western Indochina subregions are separated by the Naga Hills, Chin Hills, and Rakhine Yoma mountain ranges. Our findings highlight that the freshwater bivalve fauna of Southeast Asia primarily originated within three evolutionary hotspots (Western Indochina, Sundaland, and East Asian) supplemented by ancient immigrants from the Indian Subcontinent.
Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through technology have resulted in overcrowded and often ...conflicted spaces. The recent global move towards development of national blue economy strategies further highlights the increased focus on coastal resources to address a broad range of blue growth industries. The need to manage sustainable development and future exploitation of both over-utilised and emergent coastal resources is both a political and environmental complexity. To address this complexity, we draw on the perspectives of a multi-disciplinary team, utilising two in depth exemplary case studies in New Zealand and within the Myanmar Delta Landscape, to showcase barriers, pathways and actions that facilitate a move from Business as Usual (BAU) to a future aligned with the Sustainable Development Goals (SDGs) and the UN International Decade of Ocean Science for Sustainable Development 2021–2030. We provide key recommendations to guide interest groups, and nations globally, towards sustainable utilisation, conservation and preservation of their marine environments in a fair and equitable way, and in collaboration with those who directly rely upon coastal ecosystems. We envision a sustainable future driven by conflict mitigation and resolution, where:
Change is motivated and facilitated
Coastal ecosystems are co-managed by multiple reliant groups
Networks that maintain and enhance biodiversity are implemented
Decision-making is equitable and based on ecosystem services
Knowledge of the marine realm is strengthened—‘mapping the ocean of life’
The interests of diverse user groups are balanced with a fair distribution of benefits
Freshwater mussels cannot spread through oceanic barriers and represent a suitable model to test the continental drift patterns. Here, we reconstruct the diversification of Oriental freshwater ...mussels (Unionidae) and revise their taxonomy. We show that the Indian Subcontinent harbors a rather taxonomically poor fauna, containing 25 freshwater mussel species from one subfamily (Parreysiinae). This subfamily most likely originated in East Gondwana in the Jurassic and its representatives arrived to Asia on two Gondwanan fragments (Indian Plate and Burma Terrane). We propose that the Burma Terrane was connected with the Indian Plate through the Greater India up to the terminal Cretaceous. Later on, during the entire Paleogene epoch, these blocks have served as isolated evolutionary hotspots for freshwater mussels. The Burma Terrane collided with mainland Asia in the Late Eocene, leading to the origin of the Mekong's Indochinellini radiation. Our findings indicate that the Burma Terrane had played a major role as a Gondwanan "biotic ferry" alongside with the Indian Plate.
The systematics of Oriental freshwater mussels (Bivalvia: Unionidae) is poorly known. Here, we present an integrative revision of the genus Trapezoideus Simpson, 1900 to further understanding of ...freshwater mussel diversity in the region. We demonstrate that Trapezoideus as currently circumscribed is non-monophyletic, with its former species belonging to six other genera, one of which is new to science and described here. We recognize Trapezoideus as a monotypic genus, comprised of the type species, T. foliaceus. Trapezoideus comptus, T. misellus, T. pallegoixi, and T. peninsularis are transferred to the genus Contradens, T. subclathratus is moved to Indonaia, and T. theca is transferred to Lamellidens. Trapezoideus prashadi is found to be a junior synonym of Arcidopsis footei. Trapezoideus dallianus, T. nesemanni, T. panhai, T. peguensis, and two species new to science are placed in Yaukthwa gen. nov. This genus appears to be endemic of the Western Indochina Subregion. The two new species, Yaukthwa paiensis sp. nov. and Y. inlenensis sp. nov., are both endemic to the Salween River basin. Our results highlight that Southeast Asia is a species-rich freshwater mussel diversity hotspot with numerous local endemic species, which are in need of special conservation efforts.
Freshwater mussels (Unionida) are one of the most imperiled animal groups worldwide, revealing the fastest rates of extinction. Habitat degradation, river pollution and climate change are the primary ...causes of global decline. However, biological threats for freshwater mussels are still poorly known. Here, we describe a diverse ecological group of leeches (Hirudinea: Glossiphoniidae) inhabiting the mantle cavity of freshwater mussels. So far, examples of mussel-associated leech species are recorded from East Asia, Southeast Asia, India and Nepal, Africa, and North America. This group comprises a dozen glossiphoniid species with a hidden life style inside the mantle cavity of their hosts largely overlooked by researchers. We show that the association with freshwater mussels evolved independently in three leech clades, i.e. Batracobdelloides, Hemiclepsis, and Placobdella, at least since the Miocene. Seven mussel-associated leech species and two additional free-living taxa are described here as new to science.
Abstract
Lack of data inhibits informed decision-making and is a critical challenge in developing countries, many of which are under-resourced in financial, technical and institutional capacity to ...collect and analyse the required data. This limits the countries’ ability to achieve development goals and keeps them dependent on the provision of external resources. Development initiatives often treat capacity building and research as two separate tracks of development. While efforts have been made in the health sector to combine these through project-based learning, this approach is relatively unexplored in the water sector which by its inter-sectoral nature stands to benefit significantly from a more collaborative and solution-oriented development strategy. Capacity Building through Research (CBtR) facilitates data collection and analysis by local researchers, mentored by international experts, strengthening local capacity to produce credible evidence able to inform sustainability-related decision-making. Five case studies piloting CBtR are discussed here and evaluated through criteria of the Dutch Strategy Evaluation Protocol framework. CBtR is shown to be a long-term strategy that requires the strengthening of cross-disciplinary networks to enhance the capacity of water management institutions, which likely contributes to more efficient evidence collection and analysis suitable for decision-makers, leading to greater national resilience and reduced need for external support.
Freshwater mussels belonging to the tribe Pseudodontini (Bivalvia: Unionidae: Gonideinae) play a keystone role in riverine and lacustrine environments throughout Southeast Asia. Many of them are ...narrowly endemic and habitat specialists, which need special conservation efforts. Unfortunately, the systematics of this group is rather poorly understood. Here, we show that Pseudodon inoscularis, the type species of the genus Pseudodon, belongs to the eastern clade of the tribe (Southeast Asia, east of the Salween Basin), and, more certainly, clusters with members of the genus Monodontina. Hence, the latter genus becomes a synonym of Pseudodon, while the subtribe Pseudodontina (=Pilsbryoconchina syn. nov.) should be used as a name for the eastern clade. In turn, the genus Indopseudodon stat. rev. and the subtribe Indopseudodontina subtr. nov. must be applied as valid names for the western clade of the Pseudodontini (Ayeyarwady to Salween). We present a revision of the genus Indopseudodon with an updated synonymy and a description of a new species, I. indawgyiensis sp. nov. We also link four species-level genetic lineages from the Mekong to available taxonomic names in the genera Pseudodon and Sundadontina (Pseudodon cambodjensis, P. vagulus, Sundadontina harmandi, and S. sulcata). Based on morphological features, we revise the taxonomic position of several recent and fossil species that were traditionally placed in the Pseudodontini and transfer them to the genera Parvasolenaia, Pseudodontopsis, Ptychorhynchus, Simpsonasus nom. nov. (a new name for Nasus Simpson, 1900) (Gonideinae: Gonideini), Pseudobaphia (Unioninae: Unionini), Balwantia and Lamellidens (Parreysiinae: Lamellidentini).
Abstract
Macrobioerosion of mineral substrates in fresh water is a little-known geological process. Two examples of rock-boring bivalve molluscs were recently described from freshwater environments. ...To the best of our knowledge, rock-boring freshwater insects were previously unknown. Here, we report on the discovery of insect larvae boring into submerged siltstone (aleurolite) rocks in tropical Asia. These larvae belong to a new mayfly species and perform their borings using enlarged mandibles. Their traces represent a horizontally oriented, tunnel-like macroboring with two apertures. To date, only three rock-boring animals are known to occur in fresh water globally: a mayfly, a piddock, and a shipworm. All the three species originated within primarily wood-boring clades, indicating a simplified evolutionary shift from wood to hardground substrate based on a set of morphological and anatomical preadaptations evolved in wood borers (e.g., massive larval mandibular tusks in mayflies and specific body, shell, and muscle structure in bivalves).
Here we describe a new subgenus and three new species of parasitic water mites in the genus Unionicola (Acari: Hydrachnidia) from Myanmar: Myanmaratax subgen. nov., Unionicola (Myanmaratax) ...savadiensis subgen. and sp. nov. (hosts: Lamellidens savadiensis and L. generosus), U. (My.) generosa sp. nov. (the same hosts), and U. (My.) trapezidenssp. nov. (hosts: Trapezidens dolichorhynchus and T. angustior). These taxa were identified based on a two-gene phylogenetic analysis (COI + 28S), which also confirms the division of the genus Unionicola into numerous subgenera. The new species are cryptic species, which are morphologically indistinguishable but strongly resemble U. (Prasadatax) brandti Vidrine, 1985 described from Thailand (hosts: Lens spp. and Ensidens spp.). We also transfer the latter taxon from Prasadatax to Myanmaratax based on a set of morphological evidence and propose U. (My.) brandti comb. nov. The new subgenus contains a total of five species, one of which needs future sampling efforts and will be described elsewhere. Additionally, 56 valid subgenera, which were placed in the synonymy of the genus and in one case raised to the genus level, are restored here until robust phylogenetic evidence on their taxonomic status is available. Our results also confirm that Unionicola mites are narrow host specialists that are associated with either one or a few closely related freshwater mussel species belonging to one or two sister genera.
Uniorectangularis
Tapparone-Canefri, 1889 is a little-known nominal species of freshwater mussels described from a tributary of the Ayeyarwady River in Myanmar. This taxon was considered a synonym of
...Gibbosulalaosensis
(Lea, 1863), a margaritiferid species. However, the range of
Gibbosulalaosensis
does not encompass the Ayeyarwady River watershed. Here we re-examine the holotype of
Uniorectangularis
and provide a conchological re-description of this species. Based on conchological features such as the shell shape, elevated umbo, and the structure of lateral and pseudocardinal teeth, we transfer this taxon to the genus
Indonaia
Prashad, 1918 and propose
I.rectangularis
(Tapparone-Canefri, 1889),
comb. nov.
It appears to be a rare freshwater mussel species with a restricted range, because it has not been found since the original description. Two additional species in this genus are known from Myanmar, i.e.
Indonaiaandersoniana
(Nevill, 1877) and
I.subclathrata
(Martens, 1899).
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