The taxonomy and biogeographic history of the bivalve family Margaritiferidae are controversial b... more The taxonomy and biogeographic history of the bivalve family Margaritiferidae are controversial because previous molecular studies did not provide a well-resolved phylogenetic framework for these enigmatic freshwater mussels that have extensive but disjunct distribution in North America, Eurasia and North Africa. In this study, we present a new, fossil-calibrated phylogenetic hypothesis based on five molecular markers ($4 kb of total length) for ten species. Our results indicate that all recent margaritiferids are in the single genus, Margaritifera Schumacher, 1816. Additionally, we identified three relatively well-supported phylogenetic clades that are valid subgenera, i.e., Margaritifera s. str. (Holarctic), Margaritanopsis (=Cumberlandia) (southeast North America-southeast Asia disjunct) and Pseudunio (Mediterranean). We suggest that the crown lineage of the Margaritiferidae most likely originated in the Cretaceous (mean age 93 Ma, 95% CI 66–126 Ma). The combined results of ancestral area reconstructions based on the three different approaches (S-DIVA, DEC and S-DEC) showed that ancient vicariance events could have played an important role in speciation within the family. The rates of mitochondrial evolution of margaritiferids are notably slow, which may be associated with their longevity, long generation time and low metabolic rates. Our findings highlight the complex biogeographic history of the Margaritiferidae as an intermixing of ancient vicariance and dispersal events, which were most likely associated with some inland barriers, continental movements and a sea level dynamic.
In this paper we present the first ecological data of Indochinese freshwater pearl mussel, Margar... more In this paper we present the first ecological data of Indochinese freshwater pearl mussel, Margaritifera laosensis populations. We also provide a comparative study of the ecology of this tropical species with populations of other Margaritiferidae. We conducted surveys in ten tributaries of the River Nam Ou (Middle Mekong Drainage, Northern Laos). Reproductively viable populations were found only in the Nam Long and Nam Pe rivers, which are two of the only three known viable populations of this species in the world. The habitats of M. laosensis include mountainous oligotrophic rivers with circumneutral pH. Optimal mesohabitats are riffles and runs with a median depth of 0.2 m and median current velocity of 0.3 ms-1. Pearl mussels were more common in gravel and fine gravel riverbed substrates. Surveys revealed 252 specimens, but only 78 (31.0%) were alive. The largest mussels observed were 110 mm in length and only 11-12 years of age. The presence of smaller-sized mussels indicates recent recruitment in both populations. The most significant threats to M. laosensis populations are harvest by local people and land development in the River Nam Ou Basin.
We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 189... more We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 1891) (Lepidoptera, Erebidae, Arctiinae) from Kachin state, northern Myanmar.
The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all lis... more The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all listed by IUCN as endangered or vulnerable taxa. In this study, an extensive spatial sampling of Margaritifera spp. across the Russian Far East (Amur Basin, Kamchatka Peninsula, Kurile Archipelago and Sakhalin Island) was conducted for a revision of their taxonomy and distribution ranges. Based on their DNA sequences, shell and soft tissue morphology, three valid species were identified: Margaritifera dahurica (Middendorff, 1850), M. laevis (Haas, 1910) and M. middendorffi (Rosén, 1926). M. dahurica ranges across the Amur basin and some of the nearest river systems. M. laevis is distributed in Japan, Sakhalin Island and the Kurile Archipelago. M. middendorffi was previously considered an endemic species of the Kamchatka. However, it is widespread in the rivers of Kamchatka, Sakhalin Island, the Kurile Islands (across the Bussol Strait, which is the most significant biogeographical boundary within the archipelago), and, likely, in Japan. The Japanese species M. togakushiensis Kondo & Kobayashi, 2005 seems to be conspecific with M. middendorffi because of similar morphological patterns, small shell size (<100 mm long) and overlapped ranges, but it is in need of a separate revision. Phylogenetic analysis reveals that two NW Pacific margaritiferid species, M. laevis and M. middendorffi, formed a monophyletic 18S rDNA clade together with the North American species M. marrianae and M. falcata. The patterns that were found in these Margaritifera spp. are similar to those of freshwater fishes, indicating multiple colonizations of Eastern Asia by different mitochondrial lineages, including an ancient Beringian exchange between freshwater faunas across the Pacific.
Khodutka geothermal area is located near Khodutka and Priemysh volcanoes and is one of the larges... more Khodutka geothermal area is located near Khodutka and Priemysh volcanoes and is one of the largest geothermal areas of the Kamchatka Peninsula. Vakin (2003) described geological, geochemical and geothermic conditions of this geothermal area in detail. The main thermal water sources have temperatures up to 87°C and a discharge of approximately 150 l×sec.-1 are flows out into the warm lake with dimensions of ca. 250 m length and 80 m width. This warm river is ca. 20 m in width beginning from the lake and flows to the Bolshaya Khodutka River basin. Two local endemic Radix species were described from this geothermal area, especially Lymnaea (Radix) hadutkae Kruglov & Starobogatov, 1989 and L. (R.) thermokamtschatica Kruglov & Starobogatov, 1989 (Kruglov & Starobogatov 1989, 1993; Kruglov 2005). These species were separated using proportions of shell and reproductive system (Kruglov & Starobogatov 1989, 1993; Starobogatov et al. 2004). According to the diagnosis, L. (R.) hadutkae differs in the ear-shape shell, a form of the provaginal duct with cylindrical distal part and conical proximal part, and larger value of the index of the copulatory apparatus (ICA: proportion of the preputium to phallotheca is 1.27) from other species within the section Thermoradix Kruglov & Starobogatov, 1989. The last whorl is large, 0.86–0.89 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.15–0.16 of the aperture height. L. (R.) thermokamtschatica has the cylindrical provaginal duct, relatively short bursa duct (1.5X longer than the bursa copulatrix diameter) and very long phallotheca (ICA is 0.77). The last whorl is large, 0.85–0.87 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.2–0.25 of the aperture height. In accordance with an identification key (Starobogatov et al. 2004), the main diagnostic feature is an excess of the last whorl over the shell aperture, which has ≤0.78 and ≥0.80 of the penultimate whorl width in the first and second species, respectively. In the present paper, we revised these taxa using newly collected topotypes and additional Radix spp. specimens from other areas of the Russian Far East.
This paper continues a discussion on the number of pearl mussel species of the genus Margaritifer... more This paper continues a discussion on the number of pearl mussel species of the genus Margaritifera in northern Europe. A biometric study of 1711 pearl mussel Margaritifera margaritifera shells from 15 rivers in Russia and Latvia (basins of the White and Baltic seas) has been conducted. All the examined samples fall into two groups: the northern group (with the shells more flattened on average, f. margaritifera) and the southern one (with more convex shells, f. elongata); the boundary between these groups is at 63° N. Analysis of intrapopulation variation has shown that the samples contain individuals that correspond to f. margaritifera, f. elongata, and f. borealis. However, any hiatus between these forms is absent in all the samples, and individuals belonging to two intermediate forms are rather frequent. The hypothesis on the species specificity of the shell valve frontal section has not been confirmed based on examination of large shell samples. The pearl mussels inhabiting rivers of Northern Europe belong to a single species, M. margaritifera.
To reveal the geographical and inter-species variability of the major and trace element (TE) comp... more To reveal the geographical and inter-species variability of the major and trace element (TE) compositions of freshwater mussel shells across Eurasia, we used ICP MS after acid digestion to analyze 50 samples of shells from five species of the genus Margaritifera spp. (Bivalvia: Margaritiferidae) collected in 20 minor rivers located in NW Russia, Sakhalin, Amur basin, Kuril Islands, Kamchatka and Laos. The variations between replicates from the same site were smaller than the variations between samples from different localities or between different mollusk species. Using normed PCA, we observed significant biological and geographical controls of the trace element composition in freshwater shells,with fivemain species exhibiting distinct features of TE concentration corresponding to four major geographical locations. Four PCA factors explain 81% of the TE variability,which is closely linked to specific geographical location and weakly linked to the identity of the species. The first two factors (F1 × F2) are the element concentration and its biological affinity. The other two factors (F3 × F4) likely are the nutrient status of the river, corresponding to its proximity to wetlands or mountains, and the degree of the influence of volcanic/hydrothermal activity. The analysis ofwater samples collected during the active growth period in summer baseflow was used to quantify the distribution coefficients (Kd) of trace elements between the aragonite shells and the riverwater. All species are significantly enriched in Mn relative to the river water, with distribution coefficients of up to 5. The other elements exhibit Kd values that were similar for the five species. This suggests that the obtained distribution coefficients may be universal constants reflecting uptake of each element by the organism from the riverwater and its intracellular transport and biocalcification processes. Taken together, the chemical composition data for pearlmussel shellsmay not only reflect the geographical locality and species identity but also provide insights into biochemical processes of element uptake in the form of biominerals.
We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 189... more We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 1891) (Lepidoptera, Erebidae, Arctiinae) from Kachin state, northern Myanmar.
The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all lis... more The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all listed by IUCN as endangered or vulnerable taxa. In this study, an extensive spatial sampling of Margaritifera spp. across the Russian Far East (Amur Basin, Kamchatka Peninsula, Kurile Archipelago and Sakhalin Island) was conducted for a revision of their taxonomy and distribution ranges. Based on their DNA sequences, shell and soft tissue morphology, three valid species were identified: Margaritifera dahurica (Middendorff, 1850), M.laevis (Haas, 1910) and M.middendorffi (Rosén, 1926). M. dahurica ranges across the Amur basin and some of the nearest river systems. M.laevisis distributed in Japan, Sakhalin Island and the Kurile Archipelago. M. middendorffi was previously considered an endemic species of the Kamchatka. However, it is widespread in the rivers of Kamchatka, Sakhalin Island, the Kurile Islands (across the Bussol Strait, which is the most significant biogeographical boundary within the archipelago), and, likely, in Japan. The Japanese species M.togakushiensis Kondo&Kobayashi, 2005 seems to be conspecific with M.middendorffi because of similar morphological patterns, small shell size (<100mm long) and overlapped ranges,but it is in need of a separate revision. Phylogenetic analysis reveals that two NW Pacific margaritiferid species, M.laevisand M.middendorffi, formed a monophyletic 18S rDNA clade together with the North American species M.marrianae and M.falcata. The patterns that were found in these Margaritifera spp. are similar to those of freshwater fishes, indicating multiple colonizations of Eastern Asia by different mitochondrial lineages, including an ancient Beringian exchange between freshwater faunas across the Pacific.
The taxonomy and biogeographic history of the bivalve family Margaritiferidae are controversial b... more The taxonomy and biogeographic history of the bivalve family Margaritiferidae are controversial because previous molecular studies did not provide a well-resolved phylogenetic framework for these enigmatic freshwater mussels that have extensive but disjunct distribution in North America, Eurasia and North Africa. In this study, we present a new, fossil-calibrated phylogenetic hypothesis based on five molecular markers ($4 kb of total length) for ten species. Our results indicate that all recent margaritiferids are in the single genus, Margaritifera Schumacher, 1816. Additionally, we identified three relatively well-supported phylogenetic clades that are valid subgenera, i.e., Margaritifera s. str. (Holarctic), Margaritanopsis (=Cumberlandia) (southeast North America-southeast Asia disjunct) and Pseudunio (Mediterranean). We suggest that the crown lineage of the Margaritiferidae most likely originated in the Cretaceous (mean age 93 Ma, 95% CI 66–126 Ma). The combined results of ancestral area reconstructions based on the three different approaches (S-DIVA, DEC and S-DEC) showed that ancient vicariance events could have played an important role in speciation within the family. The rates of mitochondrial evolution of margaritiferids are notably slow, which may be associated with their longevity, long generation time and low metabolic rates. Our findings highlight the complex biogeographic history of the Margaritiferidae as an intermixing of ancient vicariance and dispersal events, which were most likely associated with some inland barriers, continental movements and a sea level dynamic.
In this paper we present the first ecological data of Indochinese freshwater pearl mussel, Margar... more In this paper we present the first ecological data of Indochinese freshwater pearl mussel, Margaritifera laosensis populations. We also provide a comparative study of the ecology of this tropical species with populations of other Margaritiferidae. We conducted surveys in ten tributaries of the River Nam Ou (Middle Mekong Drainage, Northern Laos). Reproductively viable populations were found only in the Nam Long and Nam Pe rivers, which are two of the only three known viable populations of this species in the world. The habitats of M. laosensis include mountainous oligotrophic rivers with circumneutral pH. Optimal mesohabitats are riffles and runs with a median depth of 0.2 m and median current velocity of 0.3 ms-1. Pearl mussels were more common in gravel and fine gravel riverbed substrates. Surveys revealed 252 specimens, but only 78 (31.0%) were alive. The largest mussels observed were 110 mm in length and only 11-12 years of age. The presence of smaller-sized mussels indicates recent recruitment in both populations. The most significant threats to M. laosensis populations are harvest by local people and land development in the River Nam Ou Basin.
We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 189... more We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 1891) (Lepidoptera, Erebidae, Arctiinae) from Kachin state, northern Myanmar.
The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all lis... more The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all listed by IUCN as endangered or vulnerable taxa. In this study, an extensive spatial sampling of Margaritifera spp. across the Russian Far East (Amur Basin, Kamchatka Peninsula, Kurile Archipelago and Sakhalin Island) was conducted for a revision of their taxonomy and distribution ranges. Based on their DNA sequences, shell and soft tissue morphology, three valid species were identified: Margaritifera dahurica (Middendorff, 1850), M. laevis (Haas, 1910) and M. middendorffi (Rosén, 1926). M. dahurica ranges across the Amur basin and some of the nearest river systems. M. laevis is distributed in Japan, Sakhalin Island and the Kurile Archipelago. M. middendorffi was previously considered an endemic species of the Kamchatka. However, it is widespread in the rivers of Kamchatka, Sakhalin Island, the Kurile Islands (across the Bussol Strait, which is the most significant biogeographical boundary within the archipelago), and, likely, in Japan. The Japanese species M. togakushiensis Kondo & Kobayashi, 2005 seems to be conspecific with M. middendorffi because of similar morphological patterns, small shell size (<100 mm long) and overlapped ranges, but it is in need of a separate revision. Phylogenetic analysis reveals that two NW Pacific margaritiferid species, M. laevis and M. middendorffi, formed a monophyletic 18S rDNA clade together with the North American species M. marrianae and M. falcata. The patterns that were found in these Margaritifera spp. are similar to those of freshwater fishes, indicating multiple colonizations of Eastern Asia by different mitochondrial lineages, including an ancient Beringian exchange between freshwater faunas across the Pacific.
Khodutka geothermal area is located near Khodutka and Priemysh volcanoes and is one of the larges... more Khodutka geothermal area is located near Khodutka and Priemysh volcanoes and is one of the largest geothermal areas of the Kamchatka Peninsula. Vakin (2003) described geological, geochemical and geothermic conditions of this geothermal area in detail. The main thermal water sources have temperatures up to 87°C and a discharge of approximately 150 l×sec.-1 are flows out into the warm lake with dimensions of ca. 250 m length and 80 m width. This warm river is ca. 20 m in width beginning from the lake and flows to the Bolshaya Khodutka River basin. Two local endemic Radix species were described from this geothermal area, especially Lymnaea (Radix) hadutkae Kruglov & Starobogatov, 1989 and L. (R.) thermokamtschatica Kruglov & Starobogatov, 1989 (Kruglov & Starobogatov 1989, 1993; Kruglov 2005). These species were separated using proportions of shell and reproductive system (Kruglov & Starobogatov 1989, 1993; Starobogatov et al. 2004). According to the diagnosis, L. (R.) hadutkae differs in the ear-shape shell, a form of the provaginal duct with cylindrical distal part and conical proximal part, and larger value of the index of the copulatory apparatus (ICA: proportion of the preputium to phallotheca is 1.27) from other species within the section Thermoradix Kruglov & Starobogatov, 1989. The last whorl is large, 0.86–0.89 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.15–0.16 of the aperture height. L. (R.) thermokamtschatica has the cylindrical provaginal duct, relatively short bursa duct (1.5X longer than the bursa copulatrix diameter) and very long phallotheca (ICA is 0.77). The last whorl is large, 0.85–0.87 of the shell height; an excess of the last whorl over upper margin of the aperture is 0.2–0.25 of the aperture height. In accordance with an identification key (Starobogatov et al. 2004), the main diagnostic feature is an excess of the last whorl over the shell aperture, which has ≤0.78 and ≥0.80 of the penultimate whorl width in the first and second species, respectively. In the present paper, we revised these taxa using newly collected topotypes and additional Radix spp. specimens from other areas of the Russian Far East.
This paper continues a discussion on the number of pearl mussel species of the genus Margaritifer... more This paper continues a discussion on the number of pearl mussel species of the genus Margaritifera in northern Europe. A biometric study of 1711 pearl mussel Margaritifera margaritifera shells from 15 rivers in Russia and Latvia (basins of the White and Baltic seas) has been conducted. All the examined samples fall into two groups: the northern group (with the shells more flattened on average, f. margaritifera) and the southern one (with more convex shells, f. elongata); the boundary between these groups is at 63° N. Analysis of intrapopulation variation has shown that the samples contain individuals that correspond to f. margaritifera, f. elongata, and f. borealis. However, any hiatus between these forms is absent in all the samples, and individuals belonging to two intermediate forms are rather frequent. The hypothesis on the species specificity of the shell valve frontal section has not been confirmed based on examination of large shell samples. The pearl mussels inhabiting rivers of Northern Europe belong to a single species, M. margaritifera.
To reveal the geographical and inter-species variability of the major and trace element (TE) comp... more To reveal the geographical and inter-species variability of the major and trace element (TE) compositions of freshwater mussel shells across Eurasia, we used ICP MS after acid digestion to analyze 50 samples of shells from five species of the genus Margaritifera spp. (Bivalvia: Margaritiferidae) collected in 20 minor rivers located in NW Russia, Sakhalin, Amur basin, Kuril Islands, Kamchatka and Laos. The variations between replicates from the same site were smaller than the variations between samples from different localities or between different mollusk species. Using normed PCA, we observed significant biological and geographical controls of the trace element composition in freshwater shells,with fivemain species exhibiting distinct features of TE concentration corresponding to four major geographical locations. Four PCA factors explain 81% of the TE variability,which is closely linked to specific geographical location and weakly linked to the identity of the species. The first two factors (F1 × F2) are the element concentration and its biological affinity. The other two factors (F3 × F4) likely are the nutrient status of the river, corresponding to its proximity to wetlands or mountains, and the degree of the influence of volcanic/hydrothermal activity. The analysis ofwater samples collected during the active growth period in summer baseflow was used to quantify the distribution coefficients (Kd) of trace elements between the aragonite shells and the riverwater. All species are significantly enriched in Mn relative to the river water, with distribution coefficients of up to 5. The other elements exhibit Kd values that were similar for the five species. This suggests that the obtained distribution coefficients may be universal constants reflecting uptake of each element by the organism from the riverwater and its intracellular transport and biocalcification processes. Taken together, the chemical composition data for pearlmussel shellsmay not only reflect the geographical locality and species identity but also provide insights into biochemical processes of element uptake in the form of biominerals.
We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 189... more We report the first record of Nyctemera adversata (Schaller, 1788) and N. carissima (Swinhoe, 1891) (Lepidoptera, Erebidae, Arctiinae) from Kachin state, northern Myanmar.
The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all lis... more The freshwater pearl mussel family Margaritiferidae includes 13 extant species, which are all listed by IUCN as endangered or vulnerable taxa. In this study, an extensive spatial sampling of Margaritifera spp. across the Russian Far East (Amur Basin, Kamchatka Peninsula, Kurile Archipelago and Sakhalin Island) was conducted for a revision of their taxonomy and distribution ranges. Based on their DNA sequences, shell and soft tissue morphology, three valid species were identified: Margaritifera dahurica (Middendorff, 1850), M.laevis (Haas, 1910) and M.middendorffi (Rosén, 1926). M. dahurica ranges across the Amur basin and some of the nearest river systems. M.laevisis distributed in Japan, Sakhalin Island and the Kurile Archipelago. M. middendorffi was previously considered an endemic species of the Kamchatka. However, it is widespread in the rivers of Kamchatka, Sakhalin Island, the Kurile Islands (across the Bussol Strait, which is the most significant biogeographical boundary within the archipelago), and, likely, in Japan. The Japanese species M.togakushiensis Kondo&Kobayashi, 2005 seems to be conspecific with M.middendorffi because of similar morphological patterns, small shell size (<100mm long) and overlapped ranges,but it is in need of a separate revision. Phylogenetic analysis reveals that two NW Pacific margaritiferid species, M.laevisand M.middendorffi, formed a monophyletic 18S rDNA clade together with the North American species M.marrianae and M.falcata. The patterns that were found in these Margaritifera spp. are similar to those of freshwater fishes, indicating multiple colonizations of Eastern Asia by different mitochondrial lineages, including an ancient Beringian exchange between freshwater faunas across the Pacific.
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linked to specific geographical location and weakly linked to the identity of the species. The first two factors (F1 × F2) are the element concentration and its biological affinity. The other two factors (F3 × F4) likely are the nutrient status of the river, corresponding to its proximity to wetlands or mountains, and the degree of the influence of volcanic/hydrothermal activity. The analysis ofwater samples collected during the active growth period in summer baseflow was used to quantify the distribution coefficients (Kd) of trace elements between the aragonite shells and the riverwater. All species are significantly enriched in Mn relative to the river water, with distribution
coefficients of up to 5. The other elements exhibit Kd values that were similar for the five species. This suggests that the obtained distribution coefficients may be universal constants reflecting uptake of each element by the organism from the riverwater and its intracellular transport and biocalcification processes. Taken together, the chemical composition data for pearlmussel shellsmay not only reflect the geographical locality and species identity but also provide insights into biochemical processes of element uptake in the form of biominerals.
linked to specific geographical location and weakly linked to the identity of the species. The first two factors (F1 × F2) are the element concentration and its biological affinity. The other two factors (F3 × F4) likely are the nutrient status of the river, corresponding to its proximity to wetlands or mountains, and the degree of the influence of volcanic/hydrothermal activity. The analysis ofwater samples collected during the active growth period in summer baseflow was used to quantify the distribution coefficients (Kd) of trace elements between the aragonite shells and the riverwater. All species are significantly enriched in Mn relative to the river water, with distribution
coefficients of up to 5. The other elements exhibit Kd values that were similar for the five species. This suggests that the obtained distribution coefficients may be universal constants reflecting uptake of each element by the organism from the riverwater and its intracellular transport and biocalcification processes. Taken together, the chemical composition data for pearlmussel shellsmay not only reflect the geographical locality and species identity but also provide insights into biochemical processes of element uptake in the form of biominerals.