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Species distribution models (SDMs) are an increasingly important tool for conservation particularly for difficult‐to‐study locations and with understudied fauna. Our aims were to (1) use SDMs and ensemble SDMs to predict the distribution of freshwater mussels in the Pánuco River Basin in Central México; (2) determine habitat factors shaping freshwater mussel occurrence; and (3) use predicted occupancy across a range of taxa to identify freshwater mussel biodiversity hotspots to guide conservation and management. In the Pánuco River Basin, we modeled the distributions of 11 freshwater mussel species using an ensemble approach, wherein multiple SDM methodologies were combined to create a single ensemble map of predicted occupancy. A total of 621 species‐specific observations at 87 sites were used to create species‐specific ensembles. These predictive species ensembles were then combined to create local diversity hotspot maps. Precipitation during the warmest quarter, elevation, and mean temperature were consistently the most important discriminatory environmental variables among species, whereas land use had limited influence across all taxa. To the best of our knowledge, our study is the first freshwater mussel‐focused research to use an ensemble approach to determine species distribution and predict biodiversity hotspots. Our study can be used to guide not only current conservation efforts but also prioritize areas for future conservation and study. [ABSTRACT FROM AUTHOR]

The Solimões Formation (late early Miocene to Pliocene, Brazil) yields an important fossiliferous content, but the mollusks have been scarcely studied. We studied 58 bivalve specimens from Aquidabã and Morada Nova, Eirunepé Municipality, southwestern Amazonas. They belong to Castalia ambigua (Hyriidae) and Haasica cf. balzani (Mycetopodidae). The two genera are restricted to South America. Castalia has its oldest occurrence in the late Cretaceous at Itapecuru Formation, Parnaíba Basin (Maranhão State, Brazil), and it presently has a wide distribution in South America. Haasica is currently restricted to the Paraná River Basin, and its presence in the Solimões Formation is the first in the fossil record. These strictly freshwater bivalves suggest a lacustrine environment to the upper part of the Solimões Formation. • We studied 58 bivalve specimens from Aquidabã and Morada Nova, Eirunepé Municipality, southwestern Amazonas. The species were identified Castalia ambigua (Hyriidae) and Haasica cf. balzani (Mycetopodidae). • It is the first fossil record for the Haasica. The species was known for the late Miocene Solimões Formation in Acre state, Brazil. Haasica balzani is an endemic species with a restricted recent distribution in the Alto Paraguay Basin (Paraguay River, São Paulo and Mato Grosso states, Brazil). Castalia has its oldest occurrence in the late Cretaceous at Itapecuru Formation, Parnaíba Basin (Maranhão State, Brazil), and it presently has a wide distribution in South America. • The genus Haasica and Castalia , which are typical of freshwater environments, suggest a lacustrine environment to the upper portion (Upper Miocene) of the Solimões Formation. [ABSTRACT FROM AUTHOR]

Microprojections of unionoid shells are virtually unstudied but could be important characters for resolving questions on the phylogeny and ecology of these bivalves. By investigating 26 unionoid and three species of their closest living relatives, the Trigonioida, using scanning electron microscopy, we identified three types of periostracal microprojections. (1) Microridges were present only in one species from each of the two unionoid families Mycetopodidae ( Anodontites trapesialis) and Iridinidae ( Chambardia bourguignati) and may represent a synapomorphy for the mycetopodid-iridinid clade. In A. trapesialis, microridges were additionally equipped with (2)ensp;flag-like projections (microfringes), possibly a synapomorphic character for the Mycetopodidae. Examination of partially bleached specimens indicated that both microridges and microfringes are predominantly or purely organic. In contrast, previously undescribed (3) spicule-like spikes represent calcifications within the periostracum. These were found in 20 of the 29 species and four of the six unionoid families. Spikes were particularly large and abundant in umbonal (juvenile) shell regions and species characteristic of fast-flowing habitats. These structures may thus serve in protecting the periostracum and shell underneath, and/or stabilizing life position by increasing shell friction. Microfringes and microridges, on the other hand, possibly aid in the orientation of the mussel within the sediment. [ABSTRACT FROM AUTHOR]

The genus Manota is recorded from Japan for the first time. Three new species, Manota satoyamanis, Manota indahae and Manota tunoae spp. nov., are described, based on specimens collected in an ecological sampling program of arthropods in the “satoyama” landscape of Ishikawa Prefecture. “Satoyama” represents the traditional rural landscape of Japan, which is characterized by a mosaic of secondary forests, plantations, ponds and rice paddy fields. The new species raise the number of Palearctic Manota species from five to eight. [ABSTRACT FROM AUTHOR]

We conducted a literature review and revised museum collections, as well as original datum of the authors, to create a list of the gastropod and bivalve freshwater and estuary mollusk for the Venezuelan Orinoco Basin. We consolidated a preliminary list of 104 species distributed between the Gastropod (14 families and 58 species) and Bivalve classes (13 families and 45 species). For the gastropods, the Ampullaridae family was the most diverse (22 sp.) and for the bivalves, the Mycetopodidae family (16 sp). In the list, we include the geographic distribution in the Orinoco watershed, as well as information on their local use, their sanitary importance, ecological habitat and the type of substrate associated for each species. [ABSTRACT FROM AUTHOR]

The term freshwater bivalve is very inclusive and not very informative. There are representatives of at least 19 families that have at least one representative living in freshwater. This suggests at least 14 different invasions of freshwater. At least nine families have small to large radiations in the freshwater environment: Corbiculidae, Sphaeriidae, Dreissenidae, and the unioniforme families: Hyriidae, Margaritiferidae, Unionidae, Etheriidae, Iridinidae, and Mycetopodidae. The unioniforme families contain at least 180 genera and about 800 species. This order is characterized by the unique parasitic larval stage on the gills, fins or the body of a particular host fish. This order of freshwater bivalves is suffering a very high rate of extinction, with about 37 species considered presumed extinct in North America alone. The level of endangerment and extinction facing these animals is primarily the result of habitat destruction or modification. [ABSTRACT FROM AUTHOR]

The Palaeoheterodonta is a diverse clade consisting of the freshwater bivalve order Unionoida and its marine sister group, Neotrigonia. Neotrigonia is the sole surviving genus of the Trigonioida, known from only six species in Australian waters. Unionoids (freshwater mussels), in contrast, are widespread on all continents except Antarctica and are represented by c. 900 species. Discussion is biased towards the freshwater mussel condition, but Neotrigonia is crucial as a ‘living fossil’ for establishing the plesiomorphic states of unionoid synapomorphies. Neotrigonia retains many of the characters of the ancestral heteroconch. Our object is to provide evidential support for the natural classification of the extant Palaeoheterodonta. A supermatrix of 50 taxa and 1183 characters was constructed from 62 previously published DNA sequences of mitochondrial cytochrome oxidase subunit I (COI) and 28S nuclear ribosomal DNA, 15 novel sequences, and 59 morphological characters. Published COI sequences for Coelatura aegyptiaca, Pseudomulleria dalyi, and Obliquaria reflexa were treated as potentially problematic because of their inconsistency under different methodological assumptions and conflict with other datasets. Each partition was analysed under the criterion of parsimony separately and in combined analyses; analyses were run both with and without the problematic sequences. From our ‘combined evidence’ topology (with problematic sequences excluded), the Unionoida is monophyletic on the basis of eight synapomorphies, including larval parasitism, brood protection, and restriction to freshwater. The order is composed of six families in two superfamilies, Unionoidea and Etherioidea: ((Unionidae + Margaritiferidae) + (Hyriidae + (Etheriidae + (Mycetopodidae + Iridinidae)))). The morphological synapomorphies of these taxa are discussed with an emphasis on both the diagnosing of taxa and highlighting areas of ambiguity and missing data. Three appendices provide descriptions of the morphological characters ( Appendix 1 ), a diagnosis of apomorphies for all branches of the phylogeny ( Appendix 2 ), and a family-level classification of the extant Palaeoheterodonta, including a complete synonymy ( Appendix 3 ). © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 148, 343–394. [ABSTRACT FROM AUTHOR]

Abstract: Burrowing rate index, diurnal variations in heart rate and heart rate alterations associated with behavioral patterns were studied in Anodontites trapesialis from the Pardo River (PR) and the Galo Bravo Dam (GBD). In both populations the pattern immobile/buried was associated with the lowest (basal) values of heart rate, which increase significantly during burrowing remaining steady in its phases I and II and at the first 10 min of phase III. A decrease in the frequency of digging cycles was significantly correlated with the gradual decrease in heart rate during the phase III of burrowing. Nevertheless, mussels from PR burrow faster than those of GBD and possess higher values of basal heart rate which present a diurnal variation with the higher values occurring during the light phase. Yet, the basal heart rate in mussels from GBD remained stable over the course of 24 h. Also, the increase in heart rate associated with burrowing was higher in mussels from PR and compatible with the highest burrowing index previously detected. Since mussels possess a plastic phenotype it is probable that the cited functional differences are phenotypic adaptations, but we cannot exclude the possibility of these adaptations being genotypic in nature. [Copyright &y& Elsevier]