MUSSELp Presentations

Evolution of asymmetrical glochidia in the Unionidae (Mollusca: Bivalvia)

by John M. Pfeiffer III & Daniel L. Graf

Presented at the 14th Molluscan Forum of the Malacological Society of London, 30 November 2011, London.

Abstract. Glochidial morphology has been an important character in freshwater mussel systematics for over 100 years. Despite its demonstrated taxonomic significance, glochidial morphology has not been considered in most modern phylogenetic studies. For example, five Southeast Asian genera have been observed to possess asymmetrical glochidia, which have a prominent marginal process on one of the two glochidial valves. Furthermore, these genera have never been strongly supported in any phylogenetic study. Although many larval characters are homoplastic, we hypothesize that this asymmetrical larval morphology represents a novel synapomorphy that is in disagreement with the current classification. Our research uses a combined evidence approach that utilizes mitochondrial (CO1 and 16S) and nuclear (28S) genes, as well as morphology to test the monophly of genera bearing asymmetrical glochidia. Tree estimation methods utilized include maximum parsimony, maximum likelihood and Bayesian inference. The results of this research will be discussed in the context of freshwater mussel larval evolution and classification.

Global Freshwater Bivalve Diversity

by Daniel L. Graf

Presented at the annual meeting of the American Malacological Society as part of the James H. Lee Memorial Symposium, Mollusks: The Great Unanswered Questions, 23-27 July 2011, Pittsburgh, Pennsylvania.

Abstract. Given the ecological calamity facing fresh waters, the pressing questions facing malacologists include: How many species of freshwater bivalves are there? How are they distributed? And, what are the evolutionary processes that created these patterns? The answers are fundamental to understanding the biology of the colonization of fresh waters and for setting informed conservation priorities that can mitigate the 6th mass extinction.

Opinion varies over which bivalves should be regarded as “freshwater.” For marine biologists, mere occurrence in hypoosmotic habitats has been sufficient to merit that label. It is more informative to make a distinction between those taxa that have radiated in in-land fresh waters (i.e., < 0.5 ppt) from those that are actively (or passively) colonizing upstream from estuaries. Among extant lineages, there have been (at least) three extensive radiations in fresh water: the Unionida (six families, ca. 850 spp.), the Sphaeriidae (Venerida, > 200 spp.), and the Cyrenidae (= Corbiculidae, Venerida; ca. 100 spp.). Other typically marine/brackish families have made limited excursions above sea level, including the Mytilidae, Arcidae, Donacidae, Corbulidae, Pholadidae, and Pharidae. Most of these “peripheral” freshwater species are endemic to monsoonal Asia. In addition, two euryhaline families, Dreissenidae and Cardiidae, have radiated in the “freshened” Black and Caspian seas, but few species thrive in rivers and lakes.

My talk will focus on the three major radiations of freshwater lineages. I will discuss the results of recent phylogenetic and biogeographic investigations of the Unionida, Sphaeriidae, and Cyrenidae, with an emphasis on areas of ambiguity/controversy or where research is lacking. In general, the tropical freshwater species/clades are poorly understood and among the most imperiled. Hopefully, this review will stimulate further inquiry into global “non-marine” bivalve phylogeny and ecology. This research was funded by the National Science Foundation.

The Illinois Natural History Survey/University of Illinois Museum of Natural History Mollusk Collection

by Kevin S. Cummings & Jeremy S. Tiemann

Presented at the annual meeting of the American Malacological Society, 23-27 July 2011, Pittsburgh, Pennsylvania.

Abstract. The University of Illinois Museum of Natural History (UIMNH) was “decommissioned” in 2005, and the Illinois Natural History Survey (INHS) obtained the orphaned UIMNH Mollusk collection on 1 May 2008. The UIMNH Mollusk Collection comprised about 45,000 lots of freshwater, terrestrial, and marine mollusks. The UIMNH Collection was assembled by Frank Collins Baker with a large portion of the collection coming from a donation by Anson A. Hinkley. The collection also includes specimens deposited by other early naturalists, including Richard Ellsworth Call, Phillip P. Carpenter, William Clench, Lorenzo E. Daniels, James H. Ferriss, Junius Henderson, Olof O. Nylander, Henry Pilsbry, John Wesley Powell, William S. Strode, Albert G. Wetherby, and James Zetek. It is a relatively old collection with specimens dating back to the mid-1800s. Over 135 countries are represented, but the collection is especially strong in freshwater mollusks in the Midwest and Southeastern United States and land snails from Southwestern U.S. and Central America. The INHS portion of the collection contains over 40,000 lots, most of which are freshwater bivalves and gastropods. In the past 25 years the INHS has been a repository of specimens from surveys conducted throughout the U.S. by state and federal agencies, non-governmental organizations, and private consultants. When combined, the INHS-UIMNH Mollusk Collection is one of the 20 largest mollusk collections in North America and contains over 320,000 catalogued specimens in over 70,000 lots, including approximately 600 lots containing type specimens. The combined collection has over 35,000 catalogued lots of freshwater mussels, approximately 15,000 lots of freshwater snails, nearly 15,000 lots of terrestrial snails, and about 5,000 lots of marine bivalves and gastropods. Over 40,000 soft parts of more than 200 species have been preserved (approximately half in ethanol) and are available for study. Information on the INHS Mollusk Collection can be found at http://www.inhs.illinois.edu/animals_plants/mollusk/.

Polyphyly of the freshwater mussel genus Lamprotula (Mollusca: Bivalvia: Unionidae)

by John M. Pfeiffer

Poster presented at the annual meeting of the American Malacological Society, 23-27 July 2011, Pittsburgh, Pennsylvania. Winner of the best student poster award!

An updated version of this poster was presented at the Young Systematists' Forum, 1 December 2011, London.

Abstract. The freshwater systems of Asia are among the most imperiled in the world, but conservation efforts in the region are hindered by (among other biological and sociopolitical challenges) our inability to answer basic questions about biodiversity, including the family Unionidae. Despite more than a decade of molecular phylogenetic studies on freshwater mussels, taxonomic sampling from tropical lineages has been too sparse to resolve the relationships of tropical Asian species. It is imperative that these hypotheses of relationship be tested in order to provide phylogenetic information crucial to natural resource management.

Preliminary phylogenetic analyses of mitochondrial DNA (ND1 and 16S) recovered the Asian freshwater mussel genus Lamprotula as polyphyletic (Zhou et al., 2007 Cur. Zool. 53(6): 1024-1030). However, the taxon sampling for the two data partitions were incongruent and the methods of analysis were incomplete to derive convincing conclusions. We set out to augment this published dataset by combining the two partitions into a single matrix and provide more complete ingroup and outgroup sampling by utilizing novel and published sequences. This concatenated and broader taxonomic dataset was used to test the validity of the polyphyletic nature of Lamprotula and associated family-group level relationships. Tree estimation was completed using Bayesian Inference (2 runs of 8 chains, 18 X 106 MCMC generations, retaining every 1000th tree, and omitting the first 6000 as burn-in) and Maximum Likelihood (RAxML: 2000 bootstrap replications).

This reanalysis confirms that Lamprotula is polyphyletic, recovering species in two distinct subfamily clades.  This reconstruction resolves many family-group level relationships that are not present or inconsistent with the initial analysis, including strong support for the monophly of the unionid subfamilies and the presence of a plesiomorphic unhooked larval condition. The results of these analyses of molecular phylogenetics are discussed in the context of freshwater mussel taxonomy and evolution.

Patterns of freshwater mussel richness and endemism in Africa and Madagascar

by Daniel L. Graf & Kevin S. Cummings

Presented to the Freshwater Mollusk Conservation Society, 11-15 April 2011, Louisville, Kentucky.

Abstract. Patterns of richness and endemism are among the top species-based criteria for identifying biodiversity hotspots. In order to assess these patterns among freshwater mussel species at the scale of the 90 freshwater ecoregions of Africa and Madagascar (and associated islands), we sampled specimen records from 17 major research collections on three continents. Of 6632 museum lots representing 87 species in four families, 5612 had locality data precise enough to assign them to an ecoregion. More the half of freshwater mussel species occurred in two or fewer ecoregions (48 spp.). At the opposite end of the spectrum, only three species occurred in greater than 20 ecoregions: Etheria elliptica, Chambardia wahlbergi and Mutela rostrata. Twenty-five ecoregions had no mussel records, and the two most species-rich ecoregions were the adjacent Upper Nile and Lake Victoria Basin (16 and 17 spp., respectively). The region-wide patterns of freshwater mussel richness and endemism are significantly correlated with both fish and general freshwater mollusk distributions. The relevance to these analyses to freshwater mussel conservation in Africa will be discussed.

Polyphyly of the freshwater mussel genus Lamprotula (Mollusca: Bivalvia: Unionidae)

by John M. Pfeiifer & Daniel L. Graf

Presented to the Southeastern Ecology and Evolution Conference, 25-27 March 2011, Auburn University, Auburn, Alabama. A poster of this research subsequently presented at the 2nd Annual Frontiers in Biology Research Colloquium, 20 April 2011, University of Alabama, Tuscaloosa.

Abstract. The freshwater systems of Asia are among the most imperiled waterways in the world (Dudgeon 1992, Dudgeon 2000), but conservation efforts in the region are hindered by (among other biological and sociopolitical challenges) our inability to answer basic questions about biodiversity and constituent aquatic taxa, including freshwater mussels of the family Unionidae. For example, how many lineages are present and what are their relationships to taxa in other regions. Despite more than a decade of molecular phylogenetic studies on freshwater mussels, taxonomic sampling from tropical lineages has been too sparse to resolve the relationships of the 217 tropical Asian species (Graf & Cummings, 2007). The taxonomic classification of this global freshwater mollusk hotspot predates modern cladistic methods, and is imperative that these hypotheses of relationship be tested in order to provide phylogenetic information crucial to conservation biologists and resource managers. Preliminary phylogenetic analyses of mitochondrial DNA (ND1 and 16S) of Chinese freshwater mussels recovered the genus Lamprotula as polyphyletic (Zhou et al., 2007). However, the taxon sampling for the two data partitions were incongruent and the methods of analysis were incomplete to derive convincing conclusions. We set out to augment this published dataset by combining the two partitions into a single matrix and providing more complete ingroup and outgroup taxon sampling. Our reanalysis confirms that Lamprotula is polyphyletic, recovering species from two distinct subfamily clades. The results of our analyses of molecular phylogenetics and generic nomenclature are discussed in the context of freshwater mussel taxonomy and evolution.

This slide depicts the 50% majority rule consensus topology derived from Bayesian Inference, which was identical in topology to the optimal tree from RAxML. Lamprotula (green boxes) was recovered as polyphyletic.

Click here to view (or download) an enlarged jpeg of the poster.

What, if anything, is a unionid? Coelatura Conrad, 1853 and the monophyly of the Unionidae (Bivalvia: Unionoida)

by Nathan Whelan, Anthony Geneva, and Daniel L. Graf

Presented to the Malacological Society of London Molluscan Forum, 30 November 2010, London, UK.

Abstract. The family Unionidae is the largest of the six freshwater mussel families, with around 670 species. The majority of unionid species are found on northern continents, with some lineages extending southward onto continuous Gondwanan fragments. Previous family-level phylogenetic analyses of the Unionoida had insufficient taxon sampling to test the traditional classification. As a result, there is disagreement in the literature about the monophyly of the Unionidae, primarily concerning the placement of the African species, Coelatura aegyptiaca. Analyses of mitochondrial data typically place Coelatura outside the larger Unionidae clade, confounding efforts to determine where and when this family originated. To test the phylogenetic position of Coelatura and the monophyly of the Unionidae, we specifically targeted Southeast Asian and African genera not sampled in previous molecular phylogenetic studies. We obtained sequence data of the mitochondrial cytochrome oxidase subunit I gene and the nuclear 28s ribosomal gene for 37 palaeoheterodonts as well as two outgroup taxa. Both parsimony analysis and Bayesian inference robustly recover Coelatura as a member of the Unionidae. We will discuss these results in the context of the biogeography of the family and the evolution of freshwater mussels generally. This research was funded by a grant from the USA National Science Foundation (DEB-0732903).

Click here to view (or download) an enlarged jpeg of this poster.

Coelatura and the Monophyly of the Unionidae (Bivalvia: Unionoida)

by Daniel L. Graf & Anthony Geneva

Presented to a joint meeting of the American Malacological Society and the Western Society of Malacologists, 26-30 June 2010, San Diego, California.

Abstract.The Unionidae is the largest of six freshwater mussel families with over 850 species in 165 genera. The family is well represented on the northern continents, and various lineages have extended southward onto stray Gondwanan fragments. Phylogenetic work on the Unionidae has not yet approached anything resembling comprehensive, within-family sampling. As a result, few solid conclusions can be drawn beyond (1) the fact that topologies recovered to-date have been at odds with the traditional arrangement and (2) most of the morphological characters that we thought were tremendously important for freshwater mussel classification are homoplastic and contradictory.

Since the earliest molecular phylogenetic studies of the Unionidae, the African species Coelatura aegyptiaca has been problematic. Analyses of mitochondrial DNA have repeatedly challenged the monophyly of the Unionidae, recovering Coelatura as basal to a (Margaritiferidae + Unionidae) clade (= Unionoidea). Moreover, the position of Coelatura has led to speculation about a Gondwanan origin for the otherwise northern Unionoidea.

We set out to re-evaluate the position of Coelatura with more extensive character and taxon sampling. In addition to 650+ nt of cytochrome oxidase subunit I mtDNA, we also obtained sequences for 480+ nt of 28S nuclear DNA for 39 species representing four freshwater mussel families and two outgroup species. In our analysis, the African Unionidae is represented by 3 species of Coelatura, Nitia, and Prisodontopsis. Preliminary analyses under maximum parsimony and Bayesian inference recover the Unionidae as monophyletic, with Coelatura and the other African taxa comprising the basal lineage (of those sampled). We will discuss our results in the context of global freshwater mussel evolution and competing hypotheses of the origin of the African Unionidae.

Evolution & Diversity of Freshwater Mussels (Mollusca: Bivalvia: Unionoida): Thinking Globally but Acting Locally

by Daniel L. Graf

Seminar presented at the University of Sydney, 19 March, 2010, Sydney, New South Wales, Australia.

Abstract. Freshwater mussels (Order Unionoida) are a globally distributed and ancient group of non-marine bivalve mollusks. Although the species diversity of the clade (ca. 850 spp.) represents a substantial proportion of total bivalve diversity (ca. 5-10%), in recent decades there has been an even larger disproportionate interest in freshwater mussels. This is due primarily to their imperiled conservation status. As a result, there has been an emphasis on parochial contemporary processes. The purpose of my seminar is to advocate for considering broader evolutionary patterns when interpreting local diversity.

My research on freshwater mussels focuses on diversity patterns at various scales: from families to species. I will review some (somewhat) recent family-level, phylogenetic work that I have done with an emphasis on the Hyriidae (Austrasia and Neotropics), and I will discuss my work on species-level biodiversity informatics using the Afrotropical assemblage as exemplars. Even at a continental scale, freshwater mussel communities are not “closed systems,” and the answers to local questions are more interesting when they incorporate global answers.

Freshwater Mussel Studies in Zambia 2005-2008

by Daniel L. Graf, Kevin S. Cummings, & Alex D. Chilala

Poster presented at the Agricultural & Commercial Society of Zambia Show, 31 July-3 August 2009, Lusaka Zambia.

Abstract. The Republic of Zambia in Africa is biogeographically interesting because it includes the headwaters and substantial portions of both the Congo and Zambezi river basins. In 2005, 2007, and 2008, we sampled various localities for freshwater mussels (Mollusca: Bivalvia: Unionoida) from several localities around the eastern half of the country. In addition to our own fieldwork, we have examined the holdings of various research collections in the United States and Europe. To-date, our knowledge of the freshwater mussels of Zambia is based upon relatively few specimens. However, the material we have acquired thus far has been useful not only for substantiating the Pan-African distributions of the 24 species of the Upper Congo and Upper Zambezi basins but also for testing hypotheses of evolutionary relationships among the freshwater mussels of Africa, South America, and Eurasia.

(A printed copy of our poster is available from CafePress.com). Click here to view (or download) an enlarged jpeg of this poster.

There are about 300 species of freshwater mussels in North America. Is that a lot?

by Daniel L. Graf & Kevin S. Cummings

Presented to the Freshwater Mollusk Conservation Society, 19-23 April 2009, Baltimore, Maryland.

Abstract. It sure is. We have made an extensive re-evaluation of the secondary literature in order to describe the global diversity of freshwater mussels (Bivalvia: Unionoida). Using the MUSSEL Project Database, we assigned each species to one or more geographical regions (Nearctica, Neotropica, Afrotropica, Palearctica, Indotropica, and Australasia) and subregions, and each genus was assigned to the lowest possible taxonomic rank. Based upon our analysis, there are 842 Recent freshwater mussel species (in six families) worldwide, with 302 (36%) of them (in two families) found in North America. We will discuss the geographical and taxonomic diversity of freshwater mussels and place the North American assemblage into a global context. Our worldwide species checklist is available on the MUSSEL Project Web Site (http://www.mussel-project.net/) under the heading, Unionoida cum Grano Salis. This research was funded by grants from the National Science Foundation.

Palaeoheterodonta MMVII: A Cosmopolitan Assessment of Freshwater Mussel Diversity

by Daniel L. Graf & Kevin S. Cummings

Presented at a special symposium, "Inventorying the Molluscan Fauna of the World: Frontiers and Perspectives" at the World Congress of Malacology, 16-20 July 2007, Antwerp, Belgium.

Abstract. Numerous issues complicate estimating the current state of our knowledge of the diversity of palaeoheterodonts (Bivalva: Trigonioida + Unionoida): historical and contemporary super-nomination due to typological species concepts, lumped “Biological” species concepts, outmoded higher classification, incomplete knowledge of soft-anatomical variation, and limited taxon sampling for molecular phylogenetic studies, to name a few. These shortcomings are unfortunate given freshwater mussels’ globally imperiled status and the potential utility of the group to lend insight to a wide range of evolutionary processes. Based upon cladistic analysis of nuclear (28S) and mitochondrial DNA (COI) as well as 59 morphological characters, we recovered seven paleoheterodont families: (Trigoniidae, ((Unionidae, Margaritiferidae), ((Hyriidae, (Etheriidae, (Mycetopodidae, Iridinidae)))))). A consensus arrangement of several provincial, species-level treatments yields fewer than 850 recognized, valid species worldwide, with all but 5-6 belonging to the Unionoida. We regard this as an under-estimate. While there are, no doubt, more species to be described, thorough taxonomic revisions are hindered by the ca. 4900 available species-group level nomina. We will discuss patterns of regional and taxonomic diversity and highlight the value of the MUSSEL Project Database for synthetic and revisionary studies of the Palaeoheterodonta.

Preliminary Reevaluation of the Freshwater Mussels (Bivalvia: Unionoida) of the Congo Region, Africa

by Daniel L. Graf & Kevin S. Cummings

Presented to the Freshwater Mollusk Conservation Society, 12-16 March 2007, Little Rock, Arkansas.

Abstract. Based upon the range limits of freshwater mussel (Unionoida) species, we consider the Congo Region of Africa to extend from Gabon south to Angola and Zambia, east to Lake Tanganyika, including the entire Congo Basin. As part of an on-going project to revise the Gondwanan freshwater mussels, we have examined African material in fourteen major collections on three continents. Specimen lots, including associated labels, were digitally photographed, textual data were captured on-site or later from the images, and everything was combined with appropriate taxonomic data and incorporated into the MUSSEL Project Database. Those data, including images, are served via our web site (http://www.mussel-project.net/). In addition to museum work, we have made two collecting expeditions to the Congo River Basin: the Upper Congo in Zambia in 2005 and the Lower Congo in the Republic of Congo in 2006. We survived both trips. At least 34 species of freshwater mussels in three families (Unionidae, Iridinidae and Etheriidae) are known from the Congo Region; most of those species (26, 76%) are endemic to the region (or some portion thereof). We discuss the patterns of diversity of the Congo Region freshwater mussels in the context of continent-wide diversity patterns and areas of endemism within the region. This research was funded by the National Science Foundation.

Freshwater Mussels (Bivalvia: Unionoida) of the Angola Region

by Kevin S. Cummings & Daniel L. Graf

Poster presented to the Freshwater Mollusk Conservation Society, 12-16 March 2007, Little Rock, Arkansas.

Abstract. The West African nation of Angola straddles the divide between the Congo Basin and the rivers of southern Africa. The “Angola Region” (as we define it) extends beyond the borders of the political entity to encompass the Congo River including and below the Casai, the Upper Zambezi as far down as Kafue, the endorheic Okavango Basin, and the Coastal streams from the Cunene north. Based mostly upon museum work but also from our own collecting on the fringes of the Angola Region, we recognize 23 species, including a newly discovered species, Mutela wistarmorrisi Graf & Cummings, 2006. All species of the Angola Region are illustrated and distributional patterns are discussed. This research was funded by the National Science Foundation.

Click here to view (or download) an enlarged jpeg of this poster.

Thinking Globally, but Acting Locally: the MUSSELpdb and the Australasian freshwater mussels (Bivalvia: Unionoida)

by Daniel L. Graf & Kevin S. Cummings

Presented to the Malacological Society of Australasia, 6-8 December 2006, University of Wollongong, Wollongong, New South Wales.

Abstract. In most areas of the world, it is difficult for local stakeholders to revise the taxonomy of their provincial molluscan faunas because the majority of the collected specimens, including the types, are deposited in the collections of the United States and Europe. As part of an USA-NSF funded project to revise the freshwater mussels of the former Gondwanan continents, we have assembled the specimen records from 14 major molluscan collections into the MUSSEL Project Database (MUSSELpdb).

As portions of this virtual collection are verified, georeferenced and combined with associated literature-based data, we have made subsets available via the MUSSEL Project Web Site (http://www.mussel-project.net/), including all specimen records so far captured for the Australasian freshwater mussels (Australia, New Zealand, New Guinea and the Solomon Islands). As of October 2006, the MUSSELpdb contained 2662 records from Australasia, representing at least 30 species in two families (Unionidae and Hyriidae). Hopefully, the online version of the MUSSELpdb will facilitate more researchers taking a global perspective on their local freshwater mussel faunas. Our talk will describe our methods, summarize the database structure and demonstrate its utility for revision work.

Freshwater Mussels (Mollusca: Bivalvia: Unionoida) of Africa

by Daniel L. Graf

Invited lecture presented to the Jersey Cape Shell Club, 2 October 2006, Stone Harbor, New Jersey. Also presented to the Philadelphia Shell Club 18 January 2007, Philadelphia, PA. A shortened version was presented to the Board of Trustees of the Academy of Natural Sciences on 17 October.

The objective of this non-technical lecture was to introduce the history of freshwater mussel research in Africa, modern methods of analysis (including the MUSSEL Project Database), and some of the patterns of distribution of African freshwater mussels.

Freshwater Mussel (Mollusca: Unionoida) Diversity in Africa, with an Emphasis on the Nile Fauna

by Daniel L. Graf

Invited plenary lecture during the 2006 meeting of the Egyptian German Society of Zoology, 5-9 March, Fayid, Egypt.

The objective of this lecture was to review the global distribution of freshwater mussels (Order Unionoida), with an emphasis on Africa and especially the species of the Nile. It was copiously illustrated and generally well received.

Global Distribution of Freshwater Mussel Diversity

by Kevin S. Cummings & Daniel L. Graf

Poster presented at the 2005 Meeting of the Freshwater Mollusk Conservation Society, 15-18 May, St. Paul, Minnesota.

Abstract. Freshwater mussels (= pearly mussels or naiades) of the bivalves order Unionoida have a worldwide distribution, presently occurring on all non-glaciated continents. Estimates of global freshwater mussel species diversity have, in the modern era, ranged from less than 850 to more than 1200. Our census, to-date, suggests that the actual number is closer around 900 extant (or recently extinct) species, many with multiple recognized subspecies. Nearly 5000 species-group taxa have been described for the Recent Unionoida, and we have been working in collaboration since 2002 to vet the available taxonomic data and refine our estimate of the global freshwater diversity. While the order Unionoida is worldwide in distribution, the numerous individual species are not. On a global scale, most freshwater mussel species are restricted to relatively few adjacent drainage basins, and almost none have ranges across continental boundaries. Nor are freshwater mussel species randomly distributed. Certain regions are apparent 'hot spots' of freshwater mussel diversity, most notably the southeastern United States and southeast Asia. To illustrate the global distribution of freshwater mussel species, we have surveyed the literature and museum collections to determine individual species ranges. These are depicted on a color-coded map of the world showing the number of species present in each country. This map is available on the MUSSEL Project Web Site (http://clade.acnatsci.org/mussel/).

Click here to view (or download) an enlarged jpeg of this poster.

Freshwater Mollusks, a Little About the Biology of an Endangered Resource

by Daniel L. Graf

Invited public lecture during the Philadelphia Shell Show, 3 October 2004, Academy of Natural Sciences, Philadelphia, Pennsylvania.

The purpose of this lecture was to provide an interesting and entertaining introduction to freshwater malacology to a general audience. Many aspects of freshwater mollusks were addressed in detail, including morphological diversity, reproductive habits, evolution and conservation issues.

Resouces for Freshwater Malacology: Getting in the Game

by Kevin S. Cummings

Lecture presented at a special symposium, "Mussels in America — Shells of their Former Selves," at the annual meeting of the American Fisheries Society, 22-26 August 2004, Madison, Wisconsin.

Abstract. One of the most frustrating things about beginning a new field of study is knowing where to find information. Today, many resources on freshwater mollusks are available to the beginning researcher, a large part of which is available on the web. A review of the kinds of resources available and their location will be presented. Included will be links to a bibliography of over 14,000 citations on freshwater mollusks, a freshwater mussel/fish host database, a list of systematic research collections and their respective curators, on-line catalogues of specimens, field guides, checklists, keys, photographs, societies and journals, listservers, contacts/researchers, past malacologists, exotic species, and outreach sites. A summary of the most often used references will be discussed. A new effort to try and bring some order to the overwhelming number of scientific names of freshwater mussels called the MUSSEL Project will also be presented. The MUSSEL Project is an on-going study aimed at the global revision of the classification of freshwater mussels. Toward this end, an exhaustive database of all recent mussel species and genera described to-date is being assembled. This database will eventually serve as the basis for a universal synthesis and revision of freshwater mussel taxonomy.

Evolution and Systematics of Nearctic Freshwater Mussels

by Daniel L. Graf

Lecture presented at a special symposium, "Mussels in America — Shells of their Former Selves," at the annual meeting of the American Fisheries Society, 22-26 August 2004, Madison, Wisconsin.

Abstract. Freshwater mussels of the bivalve order Unionoida are an ancient, widespread and diverse group of mollusks. However, the region of greatest species diversity is the eastern half of the North American continent. Recent cladistic analyses have shown that the Nearctic mussel assemblage is comprised of representatives of at least four distinct lineages: Anodontini, Gonideini, Ambleminae and Margaritiferidae. The global phylogenetic and biogeographic contexts for these clades will be discussed.

Palaeoheterodont Diversity: What We Know and What We Wish We Knew About Freshwater Mussel Evolution

by Daniel L. Graf & Kevin S. Cummings

Lecture presented at a special symposium, "Bivalve Systematics - a look at the branches," at the World Congress of Malacology, 11-16 July 2004, Perth, Western Australia. This lecture was also presented as part of the ANSP Seminar Series on 8 October 2004.

“When you know a thing, to hold that you know it;
and when you do not know a thing, to allow that you do not know it —
this is knowledge.” Confucius

Abstract. The Palaeoheterodonta is a diverse clade consisting of the freshwater bivalve order Unionoida and its marine sister group, Neotrigonia. Neotrigonia is the sole surviving member of Trigonioida, known today from only 6 species restricted to Australian waters. Unionoids (also known as freshwater mussels), on the other hand, are widely distributed on all continents except Antarctica, and are represented by nearly 900 species divided among 6 families.

Discussions of palaeoheterodont diversity are numerically biased towards the freshwater mussel condition, but Neotrigonia is crucial as a 'living fossil' for establishing the plesiomorphic states for characters crucial to unionoid systematics. In fact, based on recent cladistic studies, Neotrigonia appears to retain many of the characters of the ancestral heteroconch.

Based upon recent cladistic studies of both molecular and morphological data, we present a summary phylogeny of freshwater mussels emphasizing synapomorphies and sister-relationships. The Unionoida is monophyletic based upon several synapomorphies, including presence of parasitic larvae, parental care (i.e., brooding) and restriction to freshwater. The order is composed of six families divided between two superfamilies, Unionoidea and Etherioidea: ((Unionidae, Margaritiferidae), (Hyriidae, (Iridinidae, (Mycetopodidae, Etheriidae)))). This family-level phylogeny deviates from the one traditionally preferred but is supported by most cladistic analyses. The synapomorphies of these taxa, as well as problematic genera, are discussed.

Understanding the current, global diversity of the Unionoida is complicated by the absence of cosmopolitan treatments of freshwater mussel genus- and species-level assessments. Based upon our own syntheses of numerous provincial studies of freshwater mussel taxonomy, analyses of unionoid diversity in space and time are discussed with twin goals of synthesis and highlighting outstanding problems.

The Freshwater Mussels (Bivalvia: Etherioidea) of Venezuela

by Kevin S. Cummings

Lecture presented during a lunch-time seminar at the Carnegie Museum of Natural History, 22 October 2003.

Abstract. The freshwater mussel fauna of South America is very poorly known. Although studied since 1792, few areas have been adequately sampled and much of the continent remains unstudied. A.E. Ortmann published a monograph on South American naiads in 1921 but made no references to the fauna of the Rio Orinoco, one of the largest drainages on the continent. H.B. Baker was the first to monograph the land and freshwater Mollusca of Venezuela, which he published in six parts from 1923 to 1930. However, much of Venezuela remains unexplored. Venezuela is located in the northeastern portion of South America between 1 and 12 degrees North latitude and 60 and 73 West longitude. There are four principal drainages: The Maracaibo Basin in the northwest, the direct tributaries along the northern coast, the large Orinoco River system and the Essequibo drainage in the east. The country is bisected by the Andes and in the interior is a large rolling periodically flooded grassland called the Llanos.

Specimens were examined in most North American museums and fewer than 15 collection sites from the Rio Orinoco drainage were represented. Fieldwork conducted throughout Venezuela over the past nine years has added over 65 new sites and thousands of additional specimens, which has helped to clarify some distributional and taxonomic problems. Examination of the literature and museum specimens, combined with field studies, brings the total number of described mussel species recorded from Venezuela to 19. The family Hyriidae is represented by six species in the genera Castalia (2), Diplodon (2), Paxyodon (1), and Triplodon (1). The family Mycetopodidae is represented by thirteen species in the genera Anodontites (9), Lamproscapha (1), Mycetopoda (2), and Tamsiella (1). Preliminary study of recent collections suggests the possibility of four new species. The four undescribed taxa include one species each in Castalia and Diplodon and two in Anodontites. Because of the size and remoteness of the country and the wide variety of habitats present, additional collecting will undoubtedly add new species to and expand our knowledge of the freshwater bivalve fauna of Venezuela.

The Evolution of the Etherioidea (Unionoida)

by Daniel L. Graf & Kevin S. Cummings

Lecture presented at an open Bivalvia meeting honoring Prof. Brian Morton, 15-16 September 2003, Cambridge, UK. This presentation was also given the 2004 Mid-Atlantic Malacologists (MAM) Meeting at the Delaware Museum of Natural History, 13 March 2004.

Abstract. The Etherioidea, together with the Unionoidea, comprise the Unionoida, a cosmopolitan order of bivalves known colloquially as freshwater mussels or naiades. Traditionally, three families have been assigned to the Etherioidea (AKA Muteloidea) based on their unique lasidium-type larvae: Etheriidae, Mycetopodidae and Iridinidae. We also include the Hyriidae among the etherioideans based upon adult morphological characters. The superfamily is limited to the Gondwanan continents, and recent phylogenetic analyses suggest that we have not given these interesting mollusks the attention that they deserve. We will discuss our recently initiated endeavor to revise the systematics of the Etherioidea, the MUSSEL Project (http://clade.acnatsci.org/mussel).

The MUSSEL Project: Recent Global Diversity of the Freshwater Mussels (Bivalvia: Unionoida)

by Daniel L. Graf & Kevin S. Cummings

Lecture presented at the 2003 Meeting of the American Malacological Society, 26-29 June, Ann Arbor, Michigan.

Abstract. Freshwater mussels are not only interesting evolutionarily, given their Mesozoic origin, cosmopolitan distribution, complex parasitic life histories and exceptional process of cytoplasmic inheritance— they are also globally imperiled and the focus of much conservation interest. To understand and minimally explain this diversity, it is necessary to at least be able to describe it. While modern treatments of the higher taxonomy of the Unionoida have tended to rely upon hypothesis-testing (i.e., cladistics), the current consensus of species- and genus-level global mussel diversity is dependent upon the authoritarian revisions of previous generations.

A few workers of the 20th century— C.T. Simpson, F. Haas, J. Thiele, H. Modell and Ya.I. Starobogatov— provided global syntheses of freshwater mussel diversity, but only Simpson and Haas dealt at the species level; Thiele, Modell and Starobogatov restricted themselves to genera. The tendency for mussel systematists to treat geographical regions rather than clades has led to several local revisions of parts of these already-conflicting global treatments. The resulting consensus is a jury-rigged system of often incongruent taxonomies.

The MUSSEL Project (http://clade.acnatsci.org/mussel) is a collaboration, inaugurated in 2002, dedicated to pulling together this disjunct and dispersed data on unionoid taxonomy. The thrust of our efforts to-date have focused on assembling a database of the more than 4800 available names, < 20% of which are valid. We will present the results of our work to-date, including a brief description of the database we have developed for this purpose.

The MUSSEL Database Project

by Daniel L. Graf & Kevin S. Cummings

Poster presented at the 2003 Meeting of the Freshwater Mollusk Conservation Society, 16-19 March, Durham, North Carolina.

Abstract. There are roughly 4800 available species-group names for the Unionoida worldwide. There are fewer than 900 valid species known from the same group. We regard the disparity in these two values to be a major impediment to thorough taxonomic treatments of unionoid clades: Few workers have the energy to bring order to that kind of entropy. We apparently think that we do. Toward that end, we have developed a nomen/citation-based data model to manage nearly 250 years of species and generic descriptions, their associated type specimens and species (respectively), subsequent taxonomic opinions, current combinations, and distributional data. Our data model has been implemented to-date in FileMaker Pro, which presents several advantages:

• it operates seamlessly across the major computer operating systems (PC's and Macs),
• it provides a user-friendly environment for development, experimentation, and operation,
• the model is very flexible and easily adaptable for use with other taxa such as freshwater gastropods, and
• it has exciting options for diverse deliverables.

With regard to the latter, we have made subsets of our data available on the Internet (http://clade.acnatsci.org/mussel/) as well as through executables such as the Simpson-Haas Index (Coming Soon!). The Simpson-Haas Index is an on-line database where a user can type in the name of a taxon and the database will return those names thought to be valid by Simpson (1900. Synopsis of the Naiades, or pearly fresh-water mussels. Proceedings of the United States National Museum 22:501-1044) and Haas (1969. Superfamilia Unionacea. Das Tierreich (Berlin) 88:663 pp.) in their respective catalogues of worldwide unionoids.

Click here to view (or download) an enlarged jpeg of this poster.