The SVP Program Committee chooses a selection of submitted proposals for topical symposia to be presented at the annual meeting.
The Cleveland Shale and Beyond: Early Vertebrate Form, Function and Phylogeny
Wednesday, October 15
8:15 a.m. - 12:30 p.m.
Location: Renaissance Cleveland Hotel
Co-conveners: Matt Friedman, University of Chicago; Michael Coates,
University of Chicago; Phil Anderson, University of Bristol
Beginning in the 1870s, local collectors began unearthing spectacular fossil fishes from the Upper Devonian shales of the Cleveland area. The remains of giant placoderms and primitive sharks discovered by these amateurs placed Cleveland at the very heart of early vertebrate research, attracting the interest of eminent paleontologists in North America and Europe. Subsequent large-scale collecting efforts in the 1920s and 1960s resulted in additional important discoveries that form the core of the vertebrate paleontology collections at the Cleveland Museum of Natural History. The Cleveland Shale ichthyofauna is not only noteworthy for its diversity, tallying over 30 species of placoderms, chondrichthyans and osteichthyans, but also for the spectacular quality of its fossils, some of which preserve soft-tissue structures. These famous Devonian fishes are complemented by an excellent collection of articulated Mississippian tetrapods from Greer, West Virginia, that provide vital data on the anatomy of early limbed vertebrates. Together, these collections form a world-renowned resource for the study of early vertebrates, making Cleveland a clear gathering point for a diverse group of international researchers interested in the form, function and phylogeny of early vertebrates. Recent years have seen renewed interest in the study of early vertebrates, with an array of new techniques brought to bear on long-standing questions in the field. Computerized tomography permits the non-destructive examination of fine internal details of rare specimens, while the application of rigorous biomechanical modeling provides a critical test of old assertions about function and ecology. Students of early vertebrates have made important contributions at the interface between evolutionary and developmental biology, while new fossils and fresh interpretations of old specimens have challenged orthodox notions of interrelationships deep within the vertebrate tree. The primary aim of this symposium is to provide a forum for the discussion of cutting-edge research in early vertebrate paleontology, set against the backdrop of the important collections of the Cleveland Museum of Natural History. The symposium will present a superb environment within which to initiate new research partnerships, collaborations and other opportunities for the study of early vertebrate evolution.
New Directions in the Study of Fossil Endocasts: a
Symposium in Honour of Harry J. Jerison
Thursday, October 16
8:00 a.m. - 12:15 p.m.
Location: Renaissance Cleveland Hotel
Co-conveners: Grant Hurlburt, East Stroudsburg University;
Mary T. Silcox, University of Winnipeg
The study of fossil endocasts has long been critical for understanding the evolution of the brain in diverse vertebrate groups. More than any other researcher, Harry J. Jerison is responsible for providing the theoretical context for the study of endocasts. In a career now spanning more than 50 years, his work covers an extraordinary range of taxa, from the most primitive vertebrates to taxa with the most elaborate brains, including dinosaurs, birds and mammals. The wide taxonomic range studied by Dr. Jerison and other participants in this symposium epitomizes the inclusive nature of the Society of Vertebrate Paleontology. This endocast symposium will honor Dr. Jerison on the 35th anniversary of the publication of his landmark book "Evolution of the Brain and Intelligence." Endocasts are essential for understanding brain form, function and evolution in fossil vertebrates; we possess markedly more information about the brain than any other soft tissue organ of extinct vertebrates due to studying endocasts. The increasingly widespread application of CT and laser scanning technology has led to an unprecedented number of new virtual endocasts being produced. Made without time-consuming matrix removal, virtual endocasts can be made from rare specimens too valuable for the damage associated with obtaining physical endocasts. By producing virtual endocasts, we now have brain data for a much higher percentage of taxa within clades, for more ontogenetic series and for several specimens of more species than ever before. This is allowing paleontologists to investigate brain evolution and associated aspects of the biology of extinct vertebrates, including behaviour and physiology. The Encephalization Quotient (EQ), pioneered by Jerison, is a measure of relative brain size. Increasing amounts of endocast data, combined with more accurate and diverse body mass estimation methods, means that calculation of the relative size of brain and gross brain division relative size are being made with more confidence, accuracy and utility. Application of techniques from phylogenetic systematics to anatomical data from endocasts allows brain studies in evolutionary contexts, permitting us to recognize trends and patterns within lineages, and to distinguish between traits due to inheritance and those due to ecological differences. We can test hypotheses of correlation between the size and morphology of the brain or brain divisions on one hand, and ecological, biomechanical and other functional traits on the other. Traditionally, an endocast referred to a cast of the endocranial (brain) cavity; the term now also applies to casts of other cavities within the vertebrate skull, a development entirely due to scanning technologies. Previously, such examinations were exceedingly demanding, damaging and slow, when possible at all. CT scanning allows recovery of the small, complex forms of middle and inner ear cavities, the form of sinuses and the branching canals that carried blood vessels and nerves in vertebrate skulls. Inner ear endocasts give us better indications of body and head position and of auditory and balance sensory input, giving clues to locomotion and movement and explanations for increases in brain region size. This symposium both honours a pioneer and demonstrates the promise of the future through applying new technology.
Early hominid evolutionary tempo and mode between
3 Ma and 4.5 Ma
Friday, October 17
8:00 a.m. - 12:15 p.m.
Location: Renaissance Cleveland Hotel
Co-conveners: Yohannes Haile-Selassie, Cleveland Museum of Natural
History and Scott W. Simpson, Department of Anatomy, Case Western
Reserve University School of Medicine
The most parsimonious explanation of the hominid fossil record between 4.5 and 3 million years ago is of a single evolving lineage that experienced a period of rapid evolution about 4.2 Ma (Ardipithecus to Australopithecus) followed by anagenetic change through until ~2.8 Ma (Au. anamensis to Au. afarensis). Recent research in Africa has yielded substantial new fossil hominid remains allowing us to re-evaluate the tempo and mode of hominid evolution between 3 Ma and 4.5 Ma. New hominid species, such as Au. bahrelghazali and Kenyanthropus platyops, have been described perhaps documenting a greater degree of phyletic diversity during the early Pliocene than previously considered. Many fossils have been recovered from newly discovered sites in eastern Africa that bear on these issues. In light of these recently recovered hominid fossil remains, this symposium will address issues related to the context of the australopithecines and their antecedents, the fossil evidence for phyletic diversity in the Early to Middle Pliocene and anagenesis in the earliest australopithecines. The Cleveland Museum of Natural History was where the original fossil specimens of Australopithecus afarensis were studied in the 1970s and early 1980s and the species was named in the museum's scientific journal, Kirtlandia. The museum's extensive Hamann-Todd Osteological collection continues to be a valuable resource for analyses of fossil hominids and primates.
This symposium will address three main themes in hominid evolution
between 4.5 and 3.0 Ma:
1) Describe the fossil evidence and review the diagnoses for the Early and Middle Pliocene hominid species. This will provide an anatomical and contextual foundation upon which discussions of hominid evolutionary tempo and mode can be built.
2) The simplest model of human evolution between the latest Miocene and 2.7 Ma invokes a combination of anagenesis (Ardipithecus kadabba to Ar. ramidus; Australopithecus anamensis to Au. afarensis) with a punctuated event ca. 4.2 Ma (Ar. ramidus to Au. anamensis) occurring within a single lineage. However, new fossil data suggest that multiple species might have existed between 4.2 and 3.6 Ma simultaneously and that the ca. 4.2 Ma punctuated event may have been cladogenic producing multiple species rather than anagenesis of a single lineage.
3) This section will discuss the climatic context of this period by examining geological, floral and faunal evidence for patterns of change that occurred in Africa at a regional and global level. This is important to understand the factors that cause changes in adaptive strategies that may have impacted the behavioral and anatomical adaptations of the early hominids.
Fossils and the Evolutionary Patterns of Ostariophysans,
One of the Largest Vertebrate Clades
Saturday, October 18
8:00 a.m. - 12:15 p.m.
Location: Renaissance Cleveland Hotel
Co-conveners: Gloria Arratia, University of Kansas, Lawrence; and
Terry Grande, Loyola University
Today ostariophysans, with an estimated 8,000 living species, are considered
one of the most diverse clade among teleost fishes, and consequently
among vertebrates. They include groups such as characiforms (characins),
cypriniforms (e.g., minnows), gonorynchiforms (e.g., milkfishes), siluriforms
(catfishes), and gymnotiforms (knifefishes). Although they are primarily
freshwater forms, gonorynchiforms at the base are represented by both
marine and freshwater genera. As a result, ostariophysans were important
in past biogeographic theories, especially those dealing with freshwater
faunas, and more recently for establishing intercontinental relationships.
Living ostariophysans are biologically and economically important and are
currently the subject of major research projects or programs such as the "All
Ostariophysan Inventory," "Zebrafish," "Tree of Life of Cypriniformes" and
"Ontology of Cypriniformes." Most of these efforts however, are in need of
paleontological-morphological information.
The oldest record of an ostariophysan is from the Upper Jurassic of
Europe. Later, the group had its first important diversification during the
Early Cretaceous with the Gonorynchiformes. Nevertheless, the early
gonorynchiform fossil record raises major questions because our present
knowledge is based fundamentally on geographically distant forms
recovered in South America (Brazil) and Europe. There is also a major gap of information in the evolutionary history of ostariophysans that extends from the Early Cretaceous to the Eocene. The current phylogenetic hypothesis
of Ostariophysi suggests that cypriniforms should be present in the earlier
Cretaceous, and that characiforms and siluriforms should be represented by
more than just disarticulated elements such as teeth and spines. In addition,
the current state of knowledge of ostariophysan phylogenetics reveals
disagreement between hypotheses of relationships based on morphological
data (including fossils) versus molecular data. Recent molecular studies have
questioned the monophyly of the ostariophysans, as well as the monophyly of Siluriformes and Cypriniformes, by proposing that ictalurids are more
closely related to cypriniforms than to other catfishes. There are also major
discrepancies concerning the sister-group relationship of Ostariophysi.
Developmental data employing the zebrafish as a model organism are used to propose biological generalizations concerning fishes and sometimes even vertebrates. A better understanding of the place of zebrafish within ypriniforms and the Ostariophysi seems warranted. The goals of this symposium are novel and interdisciplinary: to bring paleontologists, morphologists and developmental biologists focusing on fossil and extant forms together with molecular biologists to shed light on ostariophysan evolution; to present new information on certain morphological structures, developmental traits, and their evolutionary transformations among ostariophysans; to present phylogenetic hypotheses based on both morphological and molecular data, including ages based on the fossil record versus molecular-clock data, with the aim of opening a dialogue between both fields; to present patterns of past distribution versus modern distribution of ostariophysans with respect to intercontinental connections and to evaluate the contribution of fossils to the present understanding of the group and promote the discussion of strategies to fill the large gap in the knowledge of fossil ostariophysans. This symposium will have relevance not only to those interested in ostariophysan evolution, but to a wide range of researchers, for it will bring together international specialists that will address specific topics such as the utility of paleontological, morphological, developmental and molecular data in phylogenetic reconstruction and estimating taxon age using fossils versus molecular clocks.