The MUSSELp Presentations

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.

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.

(A printed copy of our poster is available from CafePress.com). 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.