SYSTEMATICS
Theory/methods
Phylogenetic analysis of continuous data
G. Levin
Considerable controversy has surrounded the use of continuous morphological data for phylogenetic analysis, the method used to reconstruct the evolutionary relationships among organisms. Many different procedures have been proposed to discern the evidence this type of data provides. Application of these procedures to the same data set shows that some methods provide much more robust results than others. This research will be useful for taxonomists who use morphological data to try to understand the evolution of biodiversity.
Competitive disjunction: a new model of allopatric speciation
L. M. Page
Phylogenetic and distributional studies on aquatic organisms suggest that a process referred to as competitive disjunction may be commonly involved in speciation. Competitive disjunction occurs when a species invades the range of a closely related species and, through competitive exclusion, divides the resident species into two or more isolated populations. The isolates subsequently may differentiate as a result of selection or genetic drift and form new species. Competitive disjunction is recognizable phylogenetically from other forms of allopatric speciation; in competitive disjunction sister species have ranges separated by that of a related species, whereas sister species resulting from peripheral isolation or vicariance have parapatric ranges or allopatric ranges without an intervening relative. This model differs fundamentally from the peripheral isolation and vicariant models of allopatric speciation in that the extrinsic factor causing isolation of populations is biological (competition from another species) rather than physical. Recognition of competitive disjunction as a biological catalyst for allopatric speciation may lead to new explanations for species radiations and areas of high biological diversity.
Annelids
Taxonomy, systematics, and ecology of aquatic Annelida in Illinois
M.J. Wetzel
The INHS Annelida Collection consists of approximately 300,000 specimens, and includes members of the Aphanoneura, Branchiobdellida, Hirudinea, terrestrial and aquatic Oligochaeta, and Polychaeta. Although the vast majority of the material in the Collection (74%) has been collected from habitats in Illinois over the last 27 years, specimens from 45 other states, four Canadian provinces, and seven countries also are included. A computerized database that can be searched and sorted by various criteria has been established. During 1999, over 5,000 annelid specimens were identified, entered into this database, and deposited into the collection. Of these, two new state records and numerous distribution records for drainage basins in the State were documented. Annelid specimens were collected from 33 sites in Illinois and from over 30 sites located in other states. Presently, 134 species of aquatic worms representing 71 genera and 15 families are known to occur in Illinois. A summary of the INHS Annelida Collection is available via the INHS World Wide Web server.
Arthropods
Examination of the Perlesta placida complex in Illinois
R. E. DeWalt, D. W. Webb, T. N. Kompare
During the past year, specimens previously identified as Perlesta placida in the collections of the Illinois Natural History Survey were re-identified based on a recent the revision of the Perlesta placida complex. Originally, only one species Perlesta was recorded for Illinois, but based on the revised classification, seven additional species have been recorded for the state. Keys for the identification of these species, as well as their distributional patterns in Illinois are presented in a manuscript submitted to the Proceedings of the Entomological Society of Washington.
Phylogeny of the major lineages of leafhoppers and treehoppers (Insecta: Hemiptera: Membracoidea)
C. Dietrich
Leafhoppers and treehoppers comprise a highly diverse lineage of herbivorous insects. To stabilize the classification and nomenclature of the group and elucidate the factors, such as behavioral shifts and continental drift, that contributed to its evolutionary diversification, phylogenetic analyses are being performed using morphological and DNA sequence data. Results of these analyses suggest that treehoppers arose from within a specialized lineage of leafhoppers and that a shift from forest to grassland habitats may have coincided with the origin of a major lineage of leafhoppers. More details are available at: http://www.inhs.uiuc.edu/~dietrich/Leafhome.html
Molecular and morphometric systematics of pinyon pine aphids of the desert Southwest.
C. Favret
The goal of this study is to clarify the taxonomic status of several pinyon-feeding species of the genusCinara and to test alternative scenarios regarding the evolutionary diversification of the group. DNA sequence data will be used to estimate the phylogeny of the group and to examine the reliability of morphometric characters used in traditional species classifications.
Evolutionary relationships of crayfishes
C. Taylor
Crayfishes are a diverse group of North American aquatic organisms. Due to a lack of phylogenetically informative morphological characters, the evolutionary relationships of North American crayfishes are poorly known. Using molecular techniques developed for use with other animal groups, we are attempting to reconstruct the evolutionary history of crayfishes found in Illinois and other parts of the eastern United States. DNA sequence data gathered for several groups of crayfishes, including the genera Cambarus, Orconectes, and Procambarus, will be used in our analysis. Once phylogenetic information is available, distributional, ecological and behavioral characteristics of native species can be more easily explained and understood.
Aphids of Costa Rica
D. Voegtlin
An illustrated book on the aphids of Costa Rica is being prepared in cooperation with researchers at the University of Costa Rica for publication by INBIO. It will deal only with the winged morphs of the approximately 60 species that have been collected there, most in association with epidemiological studies in crops such as corn and beans. Many of the species are cosmopolitan pests that are also found in North America, including Illinois.
Therevidae of the world
M. E. Irwin, D. W. Webb, B. M. Wiegmann, D. K. Yeates
This goal of this NSF/PEET (Partnerships for Enhancing Expertise in Taxonomy) project is to complete a monograph of therevid flies of the world. In January, 2000 a two week collecting trip was made to Chile to collect therevid, rhagionid, and bombyliid flies. During the past year, a manuscript revising the genera Tabuda, Tabudamima, and Incoxoverpa was completed and published. A revision of the genera Pandivirilia and Dichoglena was completed and a manuscript is in final review before being submitted for publication.
Molecular phylogeny of the Tabanomorpha
B. M. Wiegmann, D. K. Yeates, D. W. Webb
During the past several years specimens of flies in the Tabanomorpha from around the world have been collected and identified for molecular phylogenetic analysis. During the past year, a phylogeny was constructed and compared with the current morphological phylogeny. This molecular analysis and phylogeny is currently in press in the Annals of the Entomological Society of America.
Fungi
Nomenclator of sanctioned names of fungi
J.L. Crane
In 1981, mycological nomenclature discontinued the use of latter starting dates and reverted to Linnaeus' Species Plantarum of 1753 with the provision for Sanctioned Names of Fungi. Names of fungi sanctioned under the botanical code are treated as conserved against all earlier homonyms and competing synonyms. This project traces the place of publication and nomenclatural history of each sanctioned name.
Revision of Torula Persoon: Fries
J.L. Crane & S.J. Hughes, Agriculture Canada, Ottawa
This fungal genus was established in 1794 and consists of 12 species but over 400 names in the literature. The revision will consist of revised descriptions including illustrations of the accepted species and several new species.
Plants
Systematics of three-seeded mercuries
G. Levin
Sixteen species in the plant genus Acalypha are found in the United States, including six in Illinois. Taxonomic distinctions within several species groups have been perplexing. Research including extensive field studies have shown that in some groups this is because supposedly different species are actually indistinguishable and should be treated as a single species. In other groups, however, the species are clearly distinct but some of the characteristics that have been used historically to separate them are unreliable. New identification keys and descriptions that use reliable characters have been published. Because Acalypha includes both widespread, common species and rare species, understanding the taxonomy is vital for conservation and policy-making.
Systematics of tropical Euphorbiaceae
G. Levin
Acalypha (copperleaf) and Drypetes (Guiana plum) are large genera of mainly tropical trees and shrubs, though both reach the United States and six species of Acalypha grow in Illinois. Research is underway to update the taxonomy of both genera. This work will help biologists working to conserve tropical forests and will also shed light on the distributional processes that have led to both genera being found on five continents. Revised taxonomic treatments have been published or will appear in various regional floras, including The Flora of the Venezuelan Guayana, Flora de Nicaragua, The Flora of the Greater Antilles, and Flora Malesiana.
Systematic studies of Rosaceae
K. R. Robertson
Work continued on long-term systematic studies of the Rose family (Rosaceae), especially the apple subfamily (Maloideae). K.R. Robertson was a coorganizer of a symposium held at the 1999 International Botanical Congress in St. Louis entitled "Phylogeny, Evolution, and Systematics of Rosaceae." He is collaborating with D. R. Morgan (Western Washington University) and C. S. Campbell (University of Maine) on investigating the evolutionary origin of the pome fruit using morphological and molecular techniques. Dr. Robertson is also collaborating with Chinese botanists on the treatment of subfamily Maloideae for the forthcoming English translation and updated edition of the Flora of China.
Contributions to the flora of North America
K. R. Robertson
Botanists from throughout North America are preparing manuscripts of their taxonomic specialties for a major new project that will cover all the flowering plants, conifers, and ferns for the North American continent (excluding Mexico). K. R. is contributing treatments of the Haemodoraceae (bloodwort family), which was due to be published in December 1999, the genus Erythronium (trout lily, dog-tooth violet) of the Liliaceae (lily family), and numerous genera of the Rosaceae (rose family). In addition, he will co-author the treatment of Amaranthus (Amaranthaceae, pigweed family).
Systematic studies of Jacquemontia (Convolvulaceae)
K. R. Robertson
Work is nearly complete on a taxonomic revision of the genus Jacquemontia (Convolvulaceae, Morning Glory family) in North and Central America and the West Indies. A total of 29 species are recognized. A short paper is being prepared to establish a scientific name for a group of populations from Panama that had previously included in the widespread J. pentantha; this paper will also address some problems of typification for certain species of Jacquemontia. Dr. Robertson is also collaborating with D. F. Austin (Florida Atlantic University) in preparing the treatment of Jacquemontia for the Flora Mesoamericana project and with J. L. Tapia Muñoz for the Flora Ilustrade de la Peninsula de Yucatán project.
Systematic studies of Amaranthaceae
K. R. Robertson
The Amaranthaceae (Pigweed Family) is very widespread in the eastern United States and includes numerous weeds as well as plants of natural habitats. K. R. Robertson has been studying this group for some time and had completed a taxonomic treatment of this family for the southeastern United States. A total of 12 genera are represented in the Southeast, and by far the largest genus is Amaranthus, with 23 species in the area.
Vertebrates
Evolution of size in North American freshwater fishes
J. Knouft, L. Page
Body size is one of the most important traits of a species. The relationship between body size and ecological characteristics has the potential to explain many patterns seen in nature. Cope's Rule, recognized since 1887, states that groups of organisms tend to get larger over time. However, the rule has been tested only with fossil organisms. The evolution of body size in living groups of North American fishes is being examined using published phylogenies. Results indicate that most groups of fishes, in contrast to Cope's Rule, evolve toward a smaller body size. The pattern described is extremely important in understanding community structure and species distributions.
Variation in the longear sunfish
Nick Lang, L. Page
The longear sunfish, Lepomis megalotis, is widely distributed and common in Illinois. The species has been described as "a complex of subspecies" although how the Illinois populations vary in relation to other populations is unknown. The northern longear sunfish, referred to as L. m. peltastes, has sometimes been referred to a species rather than as a subspecies, and we currently are investigating its relationship to Illinois populations of L. m. megalotis. Research is currently being conducted in order to describe the variation in the state and investigate the possibility of populations being taxonomically distinct at the species level.
Evolutionary relationships of darters and catfishes
T. Near, M. Hardman, L. Page
Darters and bullhead catfishes form large monophyletic groups of North American freshwater fishes. Although phylogenies have been developed recently for several species groups of native fishes, evolutionary relationships among and within most species groups still are poorly known. Phylogenetic analysis of DNA sequence data are being gathered for several groups of darters, including the genus Percina, and the subgenera Catonotus and Etheostoma of the genus Etheostoma, and for ictalurid catfishes. Once phylogenetic information is available, distributional, ecological and behavioral characteristics of native species can be more easily explained and understood. A manuscript describing phylogenetic relationships among the six species of Ammocrypta and the implications for modern distributions recently was accepted for publication in Copeia.