Comparative shell morphology of Dreissena polymorpha, Mytilopsis leucophaeata, and the "quagga" mussel (Bivalvia: Dreissenidae) in North America

1993 ◽  
Vol 71 (5) ◽  
pp. 1012-1023 ◽  
Author(s):  
Diane A. Pathy ◽  
Gerald L. Mackie
Keyword(s):  
North America ◽  
Shell Structure ◽  
Dreissena Polymorpha ◽  
Shell Morphology ◽  
Diagnostic Feature ◽  
Quagga Mussel ◽  
Electron Microscopic ◽  
Quagga Mussels ◽  
Freshwater Habitats ◽  
Mussel Shells

Dreissena polymorpha, recently introduced to freshwater habitats of North America, has been confused with Mytilopsis leucophaeata, a related species that is native to brackish and fresh waters of North America. The 1991 discovery of a second exotic dreissenid mussel, the "quagga" mussel, suggests there may be more than one species of Dreissena in the Great Lakes, resulting in even more confusion in identification within the family Dreissenidae. To help distinguish the species, internal and external features, ultrastructure, and composition of D. polymorpha, M. leucophaeata, and quagga mussel shells were determined using stereoscopic, scanning electron microscopic, and X-ray diffraction techniques. The most reliable diagnostic feature is the presence of an apophysis in M. leucophaeata and its absence in D. polymorpha and the quagga mussel. Mytilopsis leucophaeata and quagga mussels also lack the acute shoulder or ridge located ventrolaterally. Dreissena polymorpha, M. leucophaeata, and the quagga mussel all have an outer crossed-lamellar shell structure with an inner complex crossed-lamellar shell structure and a thin, prismatic pallial myostracum between. Microtubules are more prominent in M. leucophaeata than in D. polymorpha. No microtubules were found in the quagga mussels. Shells of D. polymorpha, M. leucophaeata, and the quagga mussel are composed entirely of aragonite crystals.

Sources of bias in the use of shell fragments to estimate the size of zebra and quagga mussels (Dreissena polymorpha and Dreissena bugensis)

1999 ◽  
Vol 77 (6) ◽  
pp. 910-916 ◽  
Author(s):  
Jeremy S Mitchell ◽  
Robert C Bailey ◽  
Richard W Knapton
Keyword(s):  
Shell Length ◽  
Dreissena Polymorpha ◽  
Zebra Mussels ◽  
Shell Morphology ◽  
Selective Predation ◽  
Dreissena Bugensis ◽  
Quagga Mussels ◽  
Length Relationship ◽  
Mussel Shells ◽  
Study Sites

Several researchers have examined size-selective predation on dreissenid mussels by first measuring septa from crushed mussel shells found in predators' gastrointestinal tracts and then using a regression of septum length on shell length to infer the size of consumed mussels. We examine three assumptions made when using this approach: (1) that the shell length : septum length relationship is site-independent within the study area, (2) where both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) are present, that the shell length : septum length relationship is the same for both mussel species, and (3) that the predator foraged exclusively at the site of collection. We collected mussels at 6 sites along an 8-km stretch of Lake Erie shoreline and found that the shell length : septum length relationship varied significantly both among sites and between zebra mussels and quagga mussels. We then compared the regression for quagga mussels at one of these sites with that for intact valves of mussels taken from scaup (Aythya marila, Aythya affinis) collected at the site. Although ice cover at the time of collection restricted scaup to the site while foraging within the study area, regressions were again significantly different, i.e., scaup had been foraging elsewhere. Our results indicate that for at least some study sites, the use of septa to estimate dreissenid mussel size is not appropriate. However, when intact valves are found in a predator, variation in shell morphology can help to confirm or exclude possible foraging locales.

Discrimination of field-collected juveniles of two introduced dreissenids (Dreissena polymorpha and Dreissena bugensis) using mitochondrial DNA and shell morphology

1997 ◽  
Vol 54 (6) ◽  
pp. 1280-1288 ◽  
Author(s):  
W Trevor Claxton ◽  
André Martel ◽  
Ronald M Dermott ◽  
Elizabeth G Boulding
Keyword(s):  
Molecular Markers ◽  
Shell Length ◽  
Dreissena Polymorpha ◽  
Restriction Pattern ◽  
Shell Morphology ◽  
Quagga Mussel ◽  
Dreissena Bugensis ◽  
Early Juvenile ◽  
Quagga Mussels ◽  
Juvenile Stages

We developed molecular markers to distinguish two species of exotic bivalves, the zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena bugensis sensu lato). Restriction analysis of a 710 base pair fragment of the COI mitochondrial gene showed a single restriction pattern for zebra mussels and a single restriction pattern for quagga mussels for each of the enzymes ScrfI, Csp6I, and Sau96I. This molecular analysis also confirmed that there were no sex-specific restriction patterns for either species. We then used our molecular markers to confirm the species identity of postmetamorphic and early juvenile stages (>=>300 µm shell length) of zebra and quagga mussels from Lake Erie and the Rideau River (Ottawa, Ont.). Useful shell characteristics to discriminate between postmetamorphic and early juvenile stages (>=>300 µm shell length) of zebra and quagga mussel included (i) overlap of valves at the posterior region, (ii) position of the dorsal point of curvature, (iii) angle of shell at the dorso-anterior region (hinge), and (iv) level of flatness of the ventral region (>2 mm shell length). Juveniles of approximately 300-700 µm shell length can be identified using the valve overlap criterion alone.

A genetic and morphological comparison of shallow- and deep-water populations of the introduced dreissenid bivalve Dreissena bugensis

1998 ◽  
Vol 76 (7) ◽  
pp. 1269-1276 ◽  
Author(s):  
W Trevor Claxton ◽  
Anthony B Wilson ◽  
Gerry L Mackie ◽  
Elizabeth G Boulding
Keyword(s):  
Dreissena Polymorpha ◽  
Mitochondrial Gene ◽  
Shell Height ◽  
Shell Morphology ◽  
Quagga Mussel ◽  
Morphological Comparison ◽  
Separate Species ◽  
Dreissena Bugensis ◽  
Shell Mass ◽  
Dreissenid Mussel

The discovery of a morphologically distinct dreissenid mussel in the profundal zone of Lake Erie suggests the presence of either a third dreissenid mussel species in the Great Lakes or a previously unknown morphological phenotype of an existing dreissenid species. We examined the morphometrics and molecular systematics of the zebra mussel (Dreissena polymorpha) and the profundal and epilimnetic forms of the quagga mussel (Dreissena bugensis) from Lakes Erie and Ontario. In an attempt to resolve the taxonomic status of the profundal form of the quagga mussel, we sequenced a 710 base pair fragment of the cytochrome oxidase subunit I mitochondrial gene of the two forms of the quagga mussel. No nucleotide differences were found, supporting the hypothesis that the profundal form of the quagga mussel is a phenotype of D. bugensis, not a separate species. In contrast, the second and third principal component scores from an analysis of the morphological variables shell length, shell width, shell height, and shell mass separated the epilimnetic and profundal forms of the quagga mussel into two groups, but grouped zebra mussels from all depths together. The most parsimonious explanation for our results is that D. bugensis shows plasticity in shell morphology with respect to depth, whereas D. polymorpha does not.

Physiological and Taxonomic Separation of Two Dreissenid Mussels in the Laurentian Great Lakes

1993 ◽  
Vol 50 (11) ◽  
pp. 2294-2297 ◽  
Author(s):  
S. Domm ◽  
R.W. McCauley ◽  
E. Kott ◽  
J. D. Ackerman
Keyword(s):  
Dreissena Polymorpha ◽  
Morphological Characteristics ◽  
Zebra Mussels ◽  
Shell Morphology ◽  
Survival Times ◽  
Quagga Mussels ◽  
Average Survival ◽  
Thermal Histories ◽  
Allozyme Loci ◽  
Ecological Differences

Physiological techniques were used to separate two related Dreissena species initially established by electrophoretic and morphological characteristics (May and Marsden. 1992. Can. J. Fish. Aquat. Sci. 49: 1501–1506). Samples of zebra mussels (Dreissena polymorpha) and "quagga" mussels (provisionally either Dreissena polymorpha andrusovi or Dreissena rostriformis bugensis) of the same size growing side by side were collected in Lake Erie, thereby ensuring that they had identical thermal histories. Upper lethal temperatures of zebra mussels were significantly higher than those of quagga mussels. The critical thermal maxima of zebra mussels acclimatized at 20 °C were half a degree higher than those of quagga mussels. The average survival times of zebra mussels held at a constant lethal temperature were also significantly longer. These results indicate that in addition to differences in allozyme loci and shell morphology, these two dreissenids may be distinguished by important physiological differences in their thermal resistance; moreover, there may be important ecological differences associated with the different species of dreissenids in North America.

Aerial exposure tolerance off zebra and quagga mussels (Bivalvia: Dreissenidae): implications for overland dispersal

1995 ◽  
Vol 52 (3) ◽  
pp. 470-477 ◽  
Author(s):  
Anthony Ricciardi ◽  
Robert Serrouya ◽  
Frederick G. Whoriskey
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Depth Distribution ◽  
Quagga Mussel ◽  
Relative Depth ◽  
Aerial Exposure ◽  
Dreissena Bugensis ◽  
Quagga Mussels ◽  
Weight Losses ◽  
St Lawrence River

We examined the effects of ambient temperature (10, 20, and 30 °C) and relative humidity (10, 50, and 95% RH) on the aerial exposure tolerance of adult zebra mussel (Dreissena polymorpha) and quagga mussel (D. bugensis) collected from the St. Lawrence River. Survivorship of mussels in air significantly increased with increasing RH, decreasing temperature, and increasing mussel size. At 20 °C and 50% RH (early temperate summer conditions), large (21–28 mm) D. polymorpha survived more than 5 days exposure, whereas small (10–18 mm) D. polymorpha survived 1–3 days. Seventy-three percent of large D. polymorpha and 10% of small D. polymorpha survived 10 days exposure at conditions considered optimal for survivorship (10 °C and 95% RH). Survivorship of D. bugensis was tested at 20 °C and was 15–100% lower than that of D. polymorpha at all RH levels combined with exposures less than 5 days. Dreissena bugensis also suffered significantly higher percent weight losses because of desiccation than D. polymorpha. The differences in the desiccation tolerance of zebra and quagga mussels reflect their relative depth distribution in lakes. Our results suggest that, given temperate summer conditions, adult Dreissena may survive overland transport (e.g., on small trailered boats) to any location within 3–5 days' drive of infested waterbodies.

Influence of physicochemical factors on the distribution and biomass of invasive mussels (Dreissena polymorpha and Dreissena bugensis) in the St. Lawrence River

2005 ◽  
Vol 62 (9) ◽  
pp. 1953-1962 ◽  
Author(s):  
Lisa A Jones ◽  
Anthony Ricciardi
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Calcium Concentration ◽  
Environmental Gradients ◽  
Stepwise Multiple Regression ◽  
Quagga Mussel ◽  
Dreissena Bugensis ◽  
Quagga Mussels ◽  
Substrate Size ◽  
St Lawrence River

Twenty sites along the St. Lawrence River were sampled to determine if the distribution and abundance of invasive mussels (zebra mussel (Dreissena polymorpha) and quagga mussel (Dreissena bugensis)) are explained by physicochemical variables. Calcium concentration, substrate size, and depth independently explained significant proportions of variation in biomass for both species. Zebra mussel populations occurred at calcium levels as low as 8 mg Ca·L–1, but quagga mussels were absent below 12 mg Ca·L–1, suggesting that they have higher calcium requirements. Both species increased in biomass with increasing substrate size but displayed contrasting patterns with depth. Using combinations of these environmental variables, we developed stepwise multiple regression models to predict zebra mussel biomass and quagga mussel biomass. The zebra mussel model included calcium concentration, substrate size, and depth (r2 = 0.36, P < 0.0001), while the quagga mussel model included only substrate size and depth (r2 = 0.32, P < 0.0001). These results suggest that dreissenid mussel abundance (and correlated impacts) will vary predictably across environmental gradients, but the same predictive model will not be accurate for both species.

Projected Distribution of the Zebra Mussel, Dreissena polymorpha, in North America

1991 ◽  
Vol 48 (8) ◽  
pp. 1389-1395 ◽  
Author(s):  
David L. Strayer
Keyword(s):  
North America ◽  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Running Waters ◽  
Population Densities ◽  
Lake Bottom ◽  
European Distribution ◽  
Cold Lakes ◽  
Warm Lakes

An analysis of the European distribution of the zebra mussel, Dreissena polymorpha, shows that the species probably will spread over much of North America. Only softwater districts and the extreme northern and southern parts of the continent are unlikely to be colonized. Within this range, D. polymorpha is most likely to be found in large, hardwater lakes and in running waters more than 30 m wide. Populations of D. polymorpha probably will spread over a larger part of the lake bottom in shallow, warm lakes than in deep, cold lakes. I could not make any predictions about the expected population densities of D. polymorpha in either lakes or streams.

Invasion of Lake Erie Offshore Sediments by Dreissena, and Its Ecological Implications

1993 ◽  
Vol 50 (11) ◽  
pp. 2298-2304 ◽  
Author(s):  
R. Dermott ◽  
M. Munawar
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Quagga Mussel ◽  
Central Basin ◽  
Eastern Basin ◽  
Fine Sediments ◽  
Ecological Implications ◽  
Large Populations ◽  
Hard Substrates

Large populations of the exotic rounded (noncarinate) shelled mussel of the genus Dreissena were found to exist on soft sediments collected throughout the central and eastern basins of Lake Erie during July and August 1992. Two different phenotypes were present on fine sediments (<150 μm) in the eastern basin. An elongated white morph was common on the profundal sediments beyond 40 m depth, while the "quagga" mussel was common on sand and sandy silt at depths between 10 and 30 m. Together with the carinated zebra mussel Dreissena polymorpha, which is very abundant on hard substrates in the sublittoral region, at least 80% of Lake Erie's bottom sediments have been invaded by Dreissena. Only that region of the central basin (near Cleveland) which undergoes periodic summer anoxia was not inhabited by this genus.

Sellaphora gologonica sp. nov. (Bacillariophyta, Sellaphoraceae), a new diatom species from a Mediterranean karst spring (Sardinia, Italy)

Phytotaxa ◽  
2018 ◽  
Vol 356 (2) ◽  
pp. 145 ◽  
Author(s):  
GIUSEPPINA G. LAI ◽  
LUC ECTOR ◽  
ANTONELLA LUGLIÈ ◽  
NICOLA SECHI ◽  
CARLOS E. WETZEL
Keyword(s):  
Diatom Species ◽  
Karst Spring ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Freshwater Habitats ◽  
Spring System ◽  
Scanning Electron ◽  
Medium Hardness

A new epilithic Sellaphora (Bacillariophyceae) species from a karst spring of Sardinia is described based on light and scanning electron microscopic observations. Sellaphora gologonica sp. nov. shares similarities with small-celled Sellaphora previously described from Europe and particularly with S. atomoides, S. hafnearae and S. seminulum. Sellaphora gologonica seems to be related to S. seminulum based on the striae patterns and valve ultrastructure, as well as the sinuous raphe system. The main differences between S. gologonica and S. seminulum lies in its valve shape (small, elliptic to oval), not presenting capitated nor protracted apices, as in the later taxon. Sellaphora gologonica was discovered in freshwater habitats with slightly alkaline and oligotrophic waters presenting medium hardness and mineralization, at the smaller water emergence of karst spring system Su Gologone (Sardinia).

Scanning Electron Microscopic Analysis of Fossil Bone (Mosasaurs) from Marine Deposits of the Upper Cretaceous of North America

1999 ◽  
Vol 5 (S2) ◽  
pp. 328-329
Author(s):  
M. Amy Sheldon
Keyword(s):  
North America ◽  
Histological Study ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Marine Deposits ◽  
Fossil Material ◽  
Destructive Analysis ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Microscopic Analysis ◽  
Scanning Electron

Research into bone histology of fossil material is a growing area of inquiry in vertebrate paleontology. Incorporating histological study into ontogenetic investigation presents new opportunities for gaining data to better understand ontogeny, ecology, and evolution of mosasaurs. Adding scanning electron microscopy to the growing technology being applied to fossil research can only further the understanding of long extinct animals.Mosasaurs were totally marine lizards which inhabited both open ocean and epicontinental seas during the late Cretaceous (Turonian through Maestrichtian), approximately 90-65. million years ago. Mosasaurs have been collected from many areas of North America. The specimens used in this study were collected from Alabama, Kansas, South Dakota, and Texas. I have restricted the fossil material for destructive analysis to ribs and vertebrae. Ribs have not been shown to have importance in morphological analysis relating to systematics or evolution, therefore their destruction does not imped the research of others. Vertebrae were isolated on outcrop but could be identified to genus and growth stage.

Sign in / Sign up

Export Citation Format

Share Document