East-central United States Research Articles

Earthquake risk from strain rates on slipping faults

Discrete geodetic measurements made near active faults may capture only small bits of a relatively complex field of deformation surrounding a fault, making it difficult to accurately describe the nature of ongoing activity along the fault. This difficulty is compounded when geodetic measurements are reported as strain rates, which involve differences in the displacement between two or more sites over time. As a result, very low displacement rates can be quoted as very high strain rates, which may lead to incorrectly inferring high seismic risk. As an example, I look at a recent deformation study across the New Madrid Seismic Zone (NMSZ). The NMSZ, located in east central United States and away from rapidly deforming plate boundaries, is best known for its series of three large earthquakes (M>7) in the early 1800s, and continues today with numerous small earthquakes (Figure 1).

Chloroplast DNA Variation Confirms a Single Origin of Domesticated Sunflower (Helianthus annuus L.)

Although sunflower was long thought to be the product of a single domestication in what is now the east-central United States, recent archaeological and genetic evidence have suggested the possibility of an independent origin of domestication, perhaps in Mexico. We therefore used hypervariable chloroplast simple-sequence repeat markers to search for evidence of a possible Mexican origin of domestication. This work resulted in the identification of 45 chloroplast haplotypes from 26 populations across the range of wild sunflower as well as 3 haplotypes from 15 domesticated lines, representing both primitive and improved cultivars. The 3 domesticated haplotypes were characterized by 1 primary haplotype (found at a frequency of 6.7% in the wild) as well as 2 rare haplotypes, which are most likely the products of mutation or introgression. One of these rare haplotypes was not observed in the wild, bringing the total number of haplotypes identified to 46. A principal coordinate analysis revealed the presence of 3 major haplotype clusters, one of which contained the primary domesticated haplotype, the 2 rare domesticated variants, as well as haplotypes found across much of the range of wild sunflower. The Mexican haplotypes, on the other hand, fell well outside of this cluster. Although our data do not provide insight into the specific location of sunflower domestication, the relative rarity of the primary domesticated haplotype in the wild, combined with the dissimilarity between this haplotype and those found in the Mexican populations surveyed, provides further evidence that the extant domesticated sunflowers are the product of a single domestication event somewhere outside of Mexico.

USING EXPERIMENTAL AND GEOSPATIAL DATA TO ESTIMATE REGIONAL CARBON SEQUESTRATION POTENTIAL UNDER NO-TILL MANAGEMENT

Conservation management of croplands at the plot scale has demonstrated a great potential to mitigate the greenhouse effect through sequestration of atmospheric carbon (C) into soil. This study estimated the potential of soil to sequester C through the conversion of croplands from conventional tillage (CT) to no-till (NT) in the East Central United States between 1992 and 2012. This study used the baseline soil organic C (SOC) pool (SOCP) inventory and the empirical models that describe the relationships of the SOCP under CT and NT, respectively, to their baseline SOCP in the upper 30-cm depth of soil. The baseline SOCP were obtained from the State Soil Geographic database, and the cropland distribution map was generated from the 1992 National Land Cover Database. The results indicate that if all the croplands under CT in 1992 were converted to NT, the SOCP would increase by 16.8% by 2012, which results in a total C sink of 136 Tg after 20 years. A greater sequestration rate would occur in soils with lower baseline SOCP, but the sink strength would be weaker with increasing SOCP levels. The CT-induced C sources tend to become larger in soils with higher baseline levels, which can be significantly reduced by adopting NT. We conclude that baseline SOC contents are an indicator of C sequestration potential with NT practices.

Bactrurus speleopolis, a new species of subterranean amphipod crustacean (Crangonyctidae) from caves in northern Arkansas

Bactrurus speleopolis, a large stygobitic amphipod crustacean in the family Crangonyctidae is described from specimens collected from a lake in Cave City Cave, Sharp County, Arkansas, and is the second species of Bactrurus Hay, 1902 recorded to date from the state. This species may also occur in Marble Falls Cave in Marion County, but sexually mature specimens are needed to verify that occurrence. The description of B. speleopolis raises the total number of species in Bactrurus to eight. The genus is widespread in subterranean groundwaters of the east-central United States and is also recorded from a few localities farther east in the southern Appalachians.

Brominated Flame Retardants in the Atmosphere of the East-Central United States

Air samples were collected at five sites (urban, semiurban, agricultural, and remote) from Lake Michigan through the U. S. Midwest to the Gulf of Mexico every 12 days during 2002-2003 using high-volume samplers so that we could study the spatial trends of brominated flame retardants (polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and 1,2-bis(2,4,6-tribromophenoxy)-ethane (TBE)). The mean sigmaPBDE atmospheric concentration was 100 +/- 35 pg/m3 at the Chicago site, which was 3-6 times higher than that at the other sites. The sigmaPBDE atmospheric concentrations at the Chicago site were significantly higher than previous measurements made in 1997-1999. Unlike these former measurements, BDE-209 is now relatively abundant. Lower BDEs (tri- through hex-BDEs) were detected in both the particle and the gas phases, and the partitioning of these compounds between phases was highly dependent on atmospheric temperature. Higher BDEs (hepta- through deca-BDEs) were mostly detected in the particle phase. On the basis of the congener distributions in the samples, the concentrations were divided into three groups: penta-BDEs, octa-BDEs, and deca-BDEs. Penta-BDEs were the most concentrated at the Chicago site and the least concentrated at the Louisiana site; octa-BDE concentrations were low at all of the sites; deca-BDEs were the most concentrated at the Chicago site and notably high atthe Arkansas site. High concentrations of deca-BDEs, HBCDs, and TBE at the Arkansas site suggest that manufacturing areas in southern Arkansas could be the source regions. Backward trajectories for air masses with high concentrations of deca-BDEs coming to the Arkansas site suggestthat deca-BDEs bound to particles can move long distances from source regions to nonsource regions.

Structural inversion and origin of a Late Ordovician (Trenton) carbonate buildup: evidence from the Tanglewood and Devils Hollow members, Lexington Limestone, central Kentucky (USA)

Throughout east–central United States, Lexington/Trenton limestones are largely Late Ordovician (Chatfieldian; mid-Caradoc), argillaceous, skeletal calcarenites, which are transgressive upward into Late Ordovician (late Chatfieldian–Edenian; mid-late Caradoc) shales and interbedded micrograined limestones. In central Kentucky, however, the same sequence is partially truncated by an unconformity and passes upward into a thicker, younger (Edenian; late Caradoc), regressive shoal complex of coarse calcarenites and calcirudites that is not generally typical of the Lexington/Trenton sequence elsewhere. The shoal complex is interpreted to have been a carbonate buildup and is partially bound by extant faults with basement precursors. Comparison of isopachous maps for pre- and postunconformity buildup units with basement structural lineaments suggests that the buildup is related to reactivation—and in one prominent case, inversion—of the basement structures. The coincidence of structural reactivation, inversion, and buildup development with other major regional, cratonic changes may reflect a reorganization of cratonic, far-field forces accompanying a nearly coeval reversal in the polarity of Taconic subduction.

Primitive cladid crinoids from the early Osagean Burlington Limestone and the phylogenetics of Mississippian species of Cyathocrinites

All 19 known species of the primitive cladid crinoid genera Atelestocrinus, Cyathocrinites, Goniocrinus, Parisocrinus, Pellecrinus, and Zygotocrinus from the early Osagean Burlington Limestone of the North American midcontinent are reviewed and redescribed or, where necessary, redefined. Nine of these species are illustrated for the first time herein. Sixteen are considered valid, including C. deroseari n. sp. Of the remaining three species, one is left in open nomenclature, and two are considered nomen dubia. Pellecrinus is recognized for the first time from the Burlington Limestone, although the specimens can not be identified to the species level and are left in open nomenclature.Cyathocrinites ranges from the Middle Silurian to at least the Middle Mississippian. During the Early Mississippian Cyathocrinites experienced an evolutionary radiation with a maximum diversity of nine species in the Burlington Limestone. Phylogenetic relationships were investigated in a parsimony-based phylogenetic analysis by combining morphologic data from the Burlington species with data from the four other species of Cyathocrinites from the late Osagean and early Meramecian of the east-central United States. The Kinderhookian C. chouteauensis (Miller and Gurley, 1896) served as the outgroup. A phylogenetic analysis of 14 species of Mississippian Cyathocrinites yielded a single most parsimonious tree with a length of 28 steps (C. I. = 0.607, H. I. = 0.392, R. I. = 0.718, R. C. = 0.436). Results of this analysis suggest that at least two major clades existed within Mississippian Cyathocrinites. One clade contains C. sampsoni (Miller, 1891b), C. gilesi (Wachsmuth and Springer, 1878), C. farleyi (Meek and Worthen, 1866), and C. barydactylus (Wachsmuth and Springer, 1878). The second clade contains C. iowensis, C. kelloggi (White, 1862), C. barrisi (Hall, 1861a), C. rigidus, C. deroseari n. sp., C. asperrimus (Springer, 1911), C. lamellosus (White, 1863), and C. harrodi (Wachsmuth and Springer, 1880). Cyathocrinites multibrachiatus forms a polytomy with these two clades. Members of the first clade exhibit a unique overall morphology present only during the Mississippian, suggesting the clade arose during this time. Members of the second clade, plus C. multibrachiatus, exhibit some characters present in Cyathocrinites species as old as the Middle Silurian and, thus, may have its roots among Silurian and Devonian species.

PRIMITIVE CLADID CRINOIDS FROM THE EARLY OSAGEAN BURLINGTON LIMESTONE AND THE PHYLOGENETICS OF MISSISSIPPIAN SPECIES OF CYATHOCRINITES

All 19 known species of the primitive cladid crinoid genera Atelestocrinus, Cyathocrinites, Goniocrinus, Parisocrinus, Pellecrinus, and Zygotocrinus from the early Osagean Burlington Limestone of the North American midcontinent are reviewed and redescribed or, where necessary, redefined. Nine of these species are illustrated for the first time herein. Sixteen are considered valid, including C. deroseari n. sp. Of the remaining three species, one is left in open nomenclature, and two are considered nomen dubia. Pellecrinus is recognized for the first time from the Burlington Limestone, although the specimens can not be identified to the species level and are left in open nomenclature.Cyathocrinites ranges from the Middle Silurian to at least the Middle Mississippian. During the Early Mississippian Cyathocrinites experienced an evolutionary radiation with a maximum diversity of nine species in the Burlington Limestone. Phylogenetic relationships were investigated in a parsimony-based phylogenetic analysis by combining morphologic data from the Burlington species with data from the four other species of Cyathocrinites from the late Osagean and early Meramecian of the east-central United States. The Kinderhookian C. chouteauensis (Miller and Gurley, 1896) served as the outgroup. A phylogenetic analysis of 14 species of Mississippian Cyathocrinites yielded a single most parsimonious tree with a length of 28 steps (C. I. = 0.607, H. I. = 0.392, R. I. = 0.718, R. C. = 0.436). Results of this analysis suggest that at least two major clades existed within Mississippian Cyathocrinites. One clade contains C. sampsoni (Miller, 1891b), C. gilesi (Wachsmuth and Springer, 1878), C. farleyi (Meek and Worthen, 1866), and C. barydactylus (Wachsmuth and Springer, 1878). The second clade contains C. iowensis, C. kelloggi (White, 1862), C. barrisi (Hall, 1861a), C. rigidus, C. deroseari n. sp., C. asperrimus (Springer, 1911), C. lamellosus (White, 1863), and C. harrodi (Wachsmuth and Springer, 1880). Cyathocrinites multibrachiatus forms a polytomy with these two clades. Members of the first clade exhibit a unique overall morphology present only during the Mississippian, suggesting the clade arose during this time. Members of the second clade, plus C. multibrachiatus, exhibit some characters present in Cyathocrinites species as old as the Middle Silurian and, thus, may have its roots among Silurian and Devonian species.

Evaluation of Low Temperature Mortality as a Range-limiting Factor for the Southwestern Corn Borer (Lepidoptera: Crambidae)

Evolutionary and ecological factors were used to assess the likelihood that low winter temperatures limit the range of Diatraea grandiosella Dyar (southwestern corn borer) in the east central United States. In controlled low-temperature mortality trials, dry diapausing laboratory-reared larvae were exposed for 2 d to constant temperatures, ranging from −6.9 to −10.0°C. Mortality of larvae originating from Indiana at the northern range edge was not significantly different from mortality of larvae from Mississippi, over 500 km to the south. However, larvae from these populations had significantly lower mortality than did those from Arizona, suggesting that selection for increased cold-hardiness may have occurred early in the species’ northeastward invasion of the central United States. Temperatures inside intact maize root crowns, the overwintering location of D. grandiosella, were measured over three winters in fields near the species’ northern range edge. Although air temperatures fell below −19°C for up to five consecutive days, root crown temperatures only approached −8°C for periods of a few hours, due primarily to an underappreciated mitigating effect of freezing soil water. Because larvae originating from the east central United States had >60% survival when exposed to −8.8°C for 2 d in the laboratory trials, mortality at the range edge caused by low temperatures was unlikely to have been severe for dry larvae during the three winters during which temperatures were measured. These results suggest that in most years, low winter temperatures are probably not the most important limiting factor at the species’ northern range edge in the east central United States.

Historic PM2.5/PM10 Concentrations in the Southeastern United States—Potential Implications of the Revised Particulate Matter Standard

ABSTRACT This report summarizes a PM2.5/PM10 particulate matter data set consisting of 861 PM2.5/PM10 sample pairs collected with dichotomous samplers by the Tennessee Valley Authority (TVA) from 1982 to 1991. Eight monitoring stations, ranging from urban-industrial to rural-background, were operated across three east-central U.S. states. Annual average PM2.5 concentrations ranged from 12.6 to 21.3 micrograms per cubic meter (μg/m3), with an overall mean of 15.7 μg/m3. Likewise, annual average PM10 concentrations ranged from 17.8 to 33.7 μg/m3, with an overall mean of 23.7 μg/m3. High summer-low winter seasonality was evident, particularly for PM2.5, with the highest monthly PM2.5 and PM10 concentrations in August (26.4 and 37.5 μg/m3, respectively) and the lowest in February (9.9 and 15.3 μg/m3, respectively). A strong association (r2 = 0.84) was found between PM and PM mass with PM mass contributing, on average, 67% of PM10 mass. Applying TVA's PM2 5/PM10 ratio to recent (1993-1995) regional high-volume PM10 Aerometric Information Retrieval System (AIRS) data for the east-central United States suggests that as many as 80% of monitored counties would have equaled or exceeded the level of the new annual PM2.5 metric of 15 μg/m3. A decline in average PM2.5 mass on the order of 3-5 μg/m3 from 1982 through 1991 is also suggested. Daily PM2 5 mass appears to be reasonably well associated (r = 0.47) with maximum hourly ozone during the warmer months (spring through fall). Sulfate compounds comprise a major portion of the measured PM2 5 mass, with that fraction being highest in the summer months. Viewed collectively, these data suggest that although compliance with the annual and 24-hr PM and 24-hr PM metrics should prove readily attainable, the annual PM2.5 metric will present a major regulatory management challenge for much of the east-central United States.

Relationships between internal and external morphology in Paleofavosites (Tabulata): the unity of growth and growth form

During growth of colonial corals, the basic organization of skeletal elements was determined by inherent factors, but arrangement of corallites within a colony could be affected if environmental change induced a modified growth form. Comparisons of internal and external characters during colony development indicate how environmental and genetic factors determined growth form. The results of these comparisons have implications for understanding of colony integration, functional morphology, and systematics.This study is based on serially sectioned coralla of the cerioid tabulate Paleofavosites subelongus, from the uppermost Ordovician to lowermost Silurian of the east-central United States. Colony growth form resulted from changes in maximum growth angle of marginal corallites, and in the shape of the growth surface. These features were coordinated with corallite characters and were dependent on variation in corallite growth. At the same time that a colony became broader by expanding its maximum growth angle and developing a taller growth surface, its corallites became larger, more new corallites were initiated, and recently initiated corallites expanded more rapidly. When a colony's maximum growth angle was reduced and the growth surface became flatter, corallites also became smaller, fewer corallites were initiated, and those corallites that were recently initiated expanded slowly.Genetic constraint of growth is illustrated by consistent patterns of initial colony growth, and by relationships among characters of internal and external morphology. Frequent small-scale variations in growth angle and growth surface height:width during astogeny indicate fluctuating environmental factors. Sedimentation and subsidence of the colony were probably the major environmental controls on form.

Quaternary grabens in southernmost Illinois: deformation near an active intraplate seismic zone

Narrow grabens displace Quaternary sediments near the northern edge of the Mississippi Embayment in extreme southern Illinois, east-central United States. Grabens are part of the Fluorspar Area Fault Complex (FAFC), which has been recurrently active throughout Phanerozoic time. The FAFC strikes directly toward the New Madrid Seismic Zone (NMSZ), scene of some of the largest intra-plate earthquakes in history. The NMSZ and FAFC share origin in a failed Cambrian rift (Reelfoot Rift). Every major fault zone of the FAFC in Illinois exhibits Quaternary displacement. The structures appear to be strike-slip pull-apart grabens, but the magnitude and direction of horizontal slip and their relationship to the current stress field are unknown. Upper Tertiary strata are vertically displaced more than 100 m, Illinoian and older Pleistocene strata 10 to 30 m, and Wisconsinan deposits 1 m or less. No Holocene deformation has been observed. Average vertical slip rates are estimated at 0.01 to 0.03 mm/year, and recurrence intervals for earthquakes of magnitude 6 to 7 are on the order of 10,000s of years for any given fault. Previous authors remarked that the small amount of surface deformation in the New Madrid area implies that the NMSZ is a young feature. Our findings show that tectonic activity has shifted around throughout the Quaternary in the central Mississippi Valley. In addition to the NMSZ and southern Illinois, the Wabash Valley (Illinois–Indiana), Benton Hills (Missouri), Crowley's Ridge (Arkansas–Missouri), and possibly other sites have experienced Quaternary tectonism. The NMSZ may be only the latest manifestation of seismicity in an intensely fractured intra-plate region.

Retrieval of Geophysical Parameters from GOES: Evaluation of a Split-Window Technique

Abstract The performance of a physical split-window retrieval algorithm used to retrieve skin temperature (ST) and precipitable water (PW) from Geostationary Operational Environmental Satellites’ (GOES) infrared measurements is evaluated. The evaluation assesses the potential of using GOES measurements to provide accurate retrieval products for climate research studies. Several algorithm performance issues are addressed, including the time of retrieval (diurnal effects), sensitivity to the first-guess field, and an evaluation of performance differences associated with the split-window channel characteristics of the GOES-7 VISSR (Visible and Infrared Spin Scan Radiometer) Atmospheric Sounder (VAS) and the GOES-8 imager and sounder. The investigation used a mesoscale model, initialized by radiosonde data, to generate a simulated atmosphere representative of a case study characterized by summertime conditions over the east-central United States. Synthetic GOES channel radiances were developed from the surrog...

Primitive cladid crinoids from upper Osagean-lower Meramecian (Mississippian) rocks of east-central United States

Species of the late Osagean and early Meramecian primitive cladid crinoid generaAtelestocrinus, Barycrinus, Cestocrinus, Costalocrinus, Cyathocrinites, Meniscocrinusn. gen.,Parisocrinus, Pellecrinus, andSaccosomopsisfrom Illinois, Indiana, Iowa, Kentucky, Missouri, and Tennessee are reviewed, redescribed, and redefined from study of type material, museum collections, and field collections. Nomenclatural and systematic acts include the following: 1)Barycrinus spurius(Hall, 1858) is a senior synonym ofCyathocrinus tumidusHall, 1858,C. protuberansHall, 1858, andB. mammatusMeek and Worthen, 1873; 2)B. rhombiferus(Owen and Shumard, 1852a) is a senior synonym ofC. sculptilisHall, 1860,C. thomaeHall, 1860,C. hoveyiHall, 1861a,C. wachsmuthiMeek and Worthen, 1861,B. herculeusMeek and Worthen, 1868,B. pentagonusMeek and Worthen, 1873,B. striatusWorthen, 1875,B. boonvillensisMiller, 1891b,B. formosusMiller and Gurley, 1894,B. washingtonensisMiller and Gurley, 1895, andB. elrodiMiller and Gurley, 1896a; 3)B. magister(Hall, 1858) is a senior synonym ofC. solidusHall, 1861a andB. magnificusMeek and Worthen, 1868; 4)B. stellatus(Hall, 1858) is a senior synonym ofC. bullatusHall, 1858,C. angulatusMeek and Worthen, 1860,C. quinquelobusMeek and Worthen, 1865, andB. astericusVan Sant, 1964; 5)B. crassibrachiatus(Hall, 1860) is a senior synonym ofB. princepsMiller and Gurley, 1890a; 6)B. geometricusMeek and Worthen, 1873, is considered a nomen dubium; 7)B. benedicti(Miller, 1891a) is considered a nomen dubium; 8)Cyathocrinus signatusMiller and Gurley, 1894, is assigned toCestocrinusand is a senior synonym ofCestocrinus striatusKirk, 1940; 9)Cyathocrinites iowensis(Owen and Shumard, 1850) is a senior synonym ofC. malvaceusHall, 1858,C. divaricatusHall, 1858,C. rotundatusHall, 1858,C. viminalisHall, 1861a,C. parvibrachiatusHall, 1861a,C. hamiltonensisWorthen, 1882,C. nodosusWachsmuth and Springer, 1890,C. brevisacculusWachsmuth and Springer, 1890,C. opimusMiller and Gurley, 1890a, andC. gurleyiMiller, 1891a; 10)C. kelloggi(White, 1862) is a senior synonym ofC. subtumidusMeek and Worthen, 1865; 11)C. farleyi(Meek and Worthen, 1866b) is a senior synonym ofC. andersoniMiller and Gurley, 1894,C. granulosusRowley, 1902, andC. snivelyiRowley, 1902; 12)C. harrodi(Wachsmuth and Springer, 1880) is a senior synonym ofC. boonvillensisMiller, 1891b,C. gorbyiMiller, 1892b, andC. astralusKammer, 1984; 13)Meniscocrinusn. gen. is described andM. magnitubusn. sp. is assigned to this new genus; 14)C. labyrinthicusMiller, 1891a, is assigned toParisocrinus; 15)C. intermediusHall, 1858, is assigned toPellecrinus; and 16)C. insperatusLyon, 1869, is assigned toSaccosomopsisand is a senior synonym ofC.?poteriumMeek and Worthen, 1870.

Survey of gold-bearing deposits of the Eastern and East-Central United States

Survey of gold-bearing deposits of the Eastern and East-Central United States

Variability in Cuphea viscosissima Jacq. collected in east-central United States

Accessions of Cuphea viscosissima were collected from the central and east-central U.S. during two field explorations, one in 1987 and the other in 1989. Characterization and evaluation data of accessions collected in 1987 have been reported earlier. This paper reports the results of characterization and evaluation trials of the 1989 collections. Thirty-one of these accessions were grown for characterization and seed-increase plantings in 1990 and twenty-four of these in replicated evaluation trials in 1991 at Ames, Iowa. Morphological characters are rather uniform and resemble accessions collected in 1987. A new pale flowered form was identified. Glandular trichomes, which produce a sticky resin, occurred uniformly on the stems and flowers of all accessions, but their presence on leaves was variable. Fourteen of the thirty-one accessions lacked glandular trichomes on their leaves. Statistically significant variation occurred in plant height (59 to 90 cm) and mass (89 to 216 g), seed yield (0.9 to 7.0 g/plant), and the amounts of caprylic (8:0) (14.3 to 16.8%), capric (10:0) (68.0 to 71.9%), and lauric (12:0) (2.5 to 3.4%) acids. Variations in 100-seed weight, seed germination, and oil content were non-significant. The narrow range of variability found in these accessions collected from rather diverse ecological regions would suggest that C. viscosissima has occupied its native range rather recently, and has had little time to diversify genetically. The variability identified is being used in interspecific hybrid crosses with C. lanceolata Aiton to develop a domestic source of medium-chain fatty acids.

Distribution and Abundance of Larval Parasitoids of European Corn Borer (Lepidoptera: Pyralidae) in the East Central United States

Overwintering Ostrinia nubilalis (Hubner) fifth instars were systematically collected at 621 sample sites on a grid interval of 40 km encompassing New York, Pennsylvania, Ohio, Delaware, Maryland, Virginia, West Virginia, and North Carolina and were evaluated for parasitoids. The study was focused on the extent of dispersal of Lydella thompsoni Herting from its presumed reestablishment in Delaware during the mid-1970s and the level of parasitism of overwintering O. nubilalis larvae. The bulk of the study was conducted in 1986 and 1987 with some additional samples taken in 1988 and 1989 from outlier locations. L. thompsoni, Macrocentrus grandii Goidanich, and Eriborus terebrans Gravenhorst were the only exotic species recovered. All three of these parasitoids were found in all states surveyed. Parasitism by these three species combined was 5.4% in 1986 and 7.5% in 1987 for the entire areas surveyed. The areas of most abundance for each species were in North Carolina for L. thompsoni , a band from northeastern Pennsylvania to eastern Virginia for M. grandii , and in Ohio for E. terebrans. All three exotic parasitoids species were retrieved at less than 3% of the sample sites. Data suggest that the dispersal rate of L. thompsoni from Delaware was about 50 km per year. An uncommon native Lixophaga sp. was found in Western Ohio and Western North Carolina. The three exotic parasitoid species appear to be well established in their respective foci of abundance.

Advanced cladid crinoids from the middle Mississippian of the east-central United States: advanced-grade calyces

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Adinocrinus, Eratocrinus, Lekocrinus n. gen., Linocrinus, Sarocrinus, and Worthenocrinus n. gen. from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. These species are considered to have advanced-grade calyces because of the substantial size reduction of the infrabasals and basals relative to the radials. Nomenclatural and systematic changes include the following: 1) Eratocrinus coxanus (Worthen, 1882) is a senior synonym of Zeacrinus keokuk Worthen, 1882; 2) E. commaticus (Miller, 1891a) is a senior synonym of Z. blairi Miller and Gurley, 1895; 3) Lekocrinus n. gen. is described and Scaphiocrinus divaricatus Hall, 1860, and Z. planobrachiatus Meek and Worthen, 1860, are assigned to this new genus; 4) Linocrinus praemorsus (Miller and Gurley, 1890a) is a senior synonym of Poteriocrinus lautus Miller and Gurley, 1896; 5) Sarocrinus kirki n. sp. is described; 6) P. varsoviensis Worthen, 1882, is assigned to Sarocrinus and is a senior synonym of P. tentaculatus Worthen, 1883, P. granilineus Miller and Gurley, 1890a, Z. pocillum Miller, 1891b, S. nitidus Kirk, 1942, and S. plenus Kirk, 1942; 7) P. asperatus Worthen, 1882, is assigned to Sarocrinus; 8) Worthenocrinus n. gen. is described and W. paterus n. sp. is assigned to this new genus; 9) Poteriocrinus iowensis Worthen, 1882, is considered a nomen dubium and placed in incertae sedis.

A new species ofPhlox (Polemoniaceae) from northern Mexico with an expanded circumscription of subsectionDivaricatae

Phlox pattersonii, a new species from the northern Sierra Madre of Coahuila and Nuevo Leon, Mexico is described. It is morphologically similar toP. pilosa var.ozarkana of the east-central United States, but differs in its suffruticose habit, alternate upper leaves, many nodes, and summer blooming period. None of the subsections ofPhlox can accommodate the new species as currently circumscribed, though it is clearly allied to subsectionsDivaricatae andDrummondianae. A new circumscription of subsect.Divaricatae is proposed which includes subsect.Drummondianae andP. pattersonii.

Advanced cladid crinoids from the middle Mississippian of the east-central United States: intermediate-grade calyces

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Abrotocrinus, Aulocrinus, Cromyocrinus. Decadocrinus, Dinotocrinus, Holcocrinus, Hylodecrinus, Lanecrinus n. gen., Pachylocrinus, Parascytalocrinus n. gen., and Stinocrinus from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. Nomenclatural and systematic acts include the following: 1) Abrotocrinus cymosus Miller and Gurley, 1890a, is a valid species and not a synonym of A. coreyi (Meek and Worthen, 1869); 2) A. coreyi is a senior synonym of Poteriocrinus orestes Worthen, 1882; 3) Scaphiocrinus manus Miller and Gurley, 1890a, is assigned to Abrotocrinus; 4) Abrotocrinus granulatus n. sp. is described; 5) S. bellus Miller and Gurley, 1890a, is assigned to Aulocrinus and is a senior synonym of Aulocrinus agassizi Wachsmuth and Springer, 1897; 6) S. orbicularis Hall, 1861a, is assigned to Cromyocrinus; 7) P. latidactylus Worthen, 1882, is assigned to Dinotocrinus; 8) S. gibsoni White, 1878, is assigned to Hylodecrinus with P. nauvooensis Worthen, 1882, questionably placed in synonymy; 9) P. briareus Worthen, 1882, is assigned to Hylodecrinus and is a senior synonym of S. lacunosus Miller and Gurley, 1890a, S. boonvillensis Miller, 1891b, S. constrictus Miller, 1891a, and S. arrosus Miller and Gurley, 1893; 10) S. bonoensis Miller and Gurley, 1890a, is assigned to Hylodecrinus; 11) Hylodecrinus robustus n. sp. is described; 12) P. validus Worthen, 1882, is questionably assigned to Hylodecrinus; 13) Lanecrinus n. gen. is described and the following species are assigned to this new genus: S. halli Hall, 1861 a, S. depressus Meek and Worthen, 1870, P. milleri Wetherby, 1881, P. fountainensis Worthen, 1882, S. repertus Miller and Gurley, 1890a, and Ramulocrinus consectatus Strimple and Watkins, 1969; P. otterensis Worthen, 1882, is questionably assigned to Lanecrinus; 14) Lanecrinus depressus is the senior synonym of P. ulrichi Worthen in Miller, 1889, and S. maniformis Miller, 1892; 15) Lanecrinus repertus is the senior synonym of S. gorbyi Miller, 1891a; 16) P. asper Worthen, 1882, is assigned to Pachylocrinus and is a senior synonym of S. extensus Wachsmuth and Springer, 1886; 17) Parascytalocrinus n. gen. is described and the following species are assigned to this new genus: Poteriocrinus hamiltonensis Worthen, 1882, and Scytalocrinus validus Wachsmuth and Springer, 1897; 18) Poteriocrinites mcadamsi Meek and Worthen, 1873, is questionably placed in synonymy with Parascytalocrinus hamiltonensis; and 19) Poteriocrinus burketi Worthen, 1882, nomen dubium and Zeacrinus dubius Miller and Gurley, 1890a, are placed in Incertae Sedis.Cromyocrinus orbicularis is the oldest species of its genus extending the range of the genus downward from the Upper to the Lower Mississippian.