A list of diatom taxa from inland waters of the northwestern United States is presented as a product of the author's bioassessment work over the last 40 years. The list is limited to taxa that have been identified from slides that are deposited in the Montana Diatom Collection. The list includes 1,348 species and infra-species taxa in 118 genera. The list is provided in support of recent efforts to compile a comprehensive and up-to-date diatom flora for the conterminous United States. Slides, acid-cleaned material, geospatial data, and/or ecological data for taxa in the checklist are available from the author.

The morphology of several “low-mantle” species of Aulacoseira found in Western North America is studied. A new taxon, Aulacoseira pardata sp. nov., is described. Aulacoseira pardata is similar to Aulacoseira distans and Aulacoseira lirata and has been confused in the past with these two taxa. Aulacoseira distans var. nivalis and Aulacoseira distans var. nivaloides bear significant morphological differences from Aulacoseira distans. These two varieties are therefore elevated to species status: Aulacoseira nivalis comb. nov. and Aulacoseira nivaloides comb. et stat. nov., respectively.

New taxa: Aulacoseira pardata English and Potapova

New combinations: Aulacoseira nivalis, Aulacoseira nivaloides.

A new diatom species, Mayamaea cahabaensis, was observed during analysis of algal samples collected from Alabama (USA) by the U.S. Geological Survey's National Water Quality Assessment Program (NAWQA). Subsequently, other populations of the same species were found in material collected for a United States Environmental Protection Agency (EPA) project also from Alabama streams. A review of NAWQA materials at the Academy of Natural Sciences of Philadelphia (ANSP) revealed that the species was also found in Arkansas, Arizona and Texas. Light microscopy (LM) and scanning electron microscopy (SEM) features reveal an affinity of the new taxon with Mayamaea Lange-Bertalot. Some of these features include elliptical valves with rounded ends and parallel to radiate striae composed of round areolae, which are occluded by a hymen positioned toward the external opening of each individual areola. The valves are slightly asymmetrical about the median transapical plane. The asymmetry of the valves and the clarity of the valve ornamentations under LM are features that are not seen in other members of the genus. The new species is eutraphentic and was found in warm waters with medium conductivity. So far, only freshwater stream populations have been found with no records from lakes.

New taxa: Mayamaea cahabaensis Morales and Manoylov

Effective landuse planning to protect stream ecosystems requires quantitative tools that link catchment landuse to stream biotic integrity. This study explores two practical catchment-scale modeling approaches to this problem. Both predict levels of sediment or nutrient stressors in stream reaches based on landcover and other geospatial data, then predict impacts of these stressor levels on metrics of stream biotic integrity using fitted stressor-response functions (SRFs). Both approaches can be applied to large numbers of catchments using only readily available geospatial data and types of biological data commonly collected by state environmental agencies. The two approaches differ in the types of stressors they address and in details of how stressor loads of catchments are predicted. Stressor variables include total sediment and dissolved, particulate, and total nitrogen and phosphorus. Biological response variables include various metrics of community structure and pollution tolerance or sensitivity. Substantial differences between the two approaches were found regarding the pairs of stressor and response variables that showed the clearest relationships in data plots, the best-fit functional forms for the SRFs, and the proportion of variation explained by the best-fit SRFs. SRFs explained up to 60 % of variation about the overall mean response. The best performing SRFs were found to generalize well to data not used in estimating function parameters, and those for two metrics (Shannon diversity and evenness) were found to be nearly identical for the two modeling approaches.

A spatially comprehensive evaluation of poly chlorinated biphenyl (PCB) inventories in white perch, channel catfish, small prey fish, amphipods and sediment within four zones of the Delaware River Estuary was completed during two seasons (fall 2001 and spring 2002). Highest sediment PCB concentrations occurred adjacent to urbanized and industrialized stretches of the estuary. Whole organism t-PCB body burdens (on a wet weight basis) reflected the spatial distributions in sediment PCB concentrations. However, there was considerable variation in PCB concentrations among individual catfish and perch fillets within zones that were not significantly reduced by lipid normalization. This variation suggests that within a zone many factors (e.g., dietary shifts, small-scale heterogeneity in sediment contamination, and non-equilibrium conditions in contaminant partitioning) drive PCB bioaccumulation. With increasing down-estuary distances, all biota except for perch had enhanced concentrations of more chlorinated congeners, especially nona- and deca-chlorinated biphenyls. Specific congeners such as PCB 206 and 209 may act as indicators of unique local sources of contamination within the lower portions of the Delaware River Estuary.

Abundant fossil plant remains are preserved in the high-latitude late Paleocene Iceberg Bay Formation on Ellesmere Island, Nunavut, Canada. Intact leaf litter lenses and permineralized, in situ logs and stumps offer for the first time an opportunity to determine the structure, biomass, and productivity of a redwood-dominated forest that grew in the polar regions of Nunavut (paleolatitude 75–80° N). Well-preserved fossil tree trunks were excavated to develop equations that describe the height, structure, and mass of the aboveground components of late Paleocene-age (approximately 55.8 to 58.7 million years old) Metasequoia (redwoods) trees. We then combined those data with measurements of the in situ stumps to determine the structure, biomass, and productivity of this polar fossil forest. The height of the canopy trees in the forest was calculated to be 32 ± 2 m. Abundant branch stubs that represent the remnants of living branches were found on a wide range of stem sizes including larger logs from the lower portions of the fossil trees indicating a relatively deep canopy. The branch lengths predicted from allometric relationships developed on modern Metasequoia trees are consistent with the stump spacing measured at Stenkul Fiord. The stem volume equaled 1,632 m³ ha^-1 and stem biomass was a minimum of 490 Mg ha^-1. Recovery of an incomplete treetop with exposed branch stubs enabled us to make minimum estimates of branch wood and foliar biomass using allometric equations derived from extant Metasequoia glyptostroboides trees in Japan. Estimated stand-level branch biomass was at most 19 Mg ha^-1 and standing foliar biomass was estimated to be a maximum of 4 Mg ha^-1. We adjusted the derived stemwood biomass estimates to account for a potential bias against sapwood and bark preservation. This adjustment increased our stemwood biomass estimates by 17% to 576 Mg ha^-1. Using the annual ring widths of the tree stems, the reconstructed parabolic stems, and wood density of modern Metasequoia, we calculated the annual wood production of the Stenkul Fiord forest to be 3.8 Mg ha^-1 yr^-1. Assuming the ancient Metasequoia trees were deciduous like their living relatives, the annual aboveground net primary productivity was between 5.8 and 7.8 Mg ha^-1 yr^-1. These estimated biomass and productivity values fall within the range for those obtained for modern old-growth forests of the Pacific Northwest (USA) and old-growth coastal Cordillera forests of southern Chile and are near the average values for temperate freshwater floodplain forests in North America.

Fertile and vegetative compression/impression remains of Taiwania Hayata (Cupressaceae) have been recovered from a number of Middle Albian (approximately 106 million years old [Ma]) to Cenomanian (99.6 to 93.5 Ma) age deposits from the North Slope of Alaska. These fossils are the oldest known for the genus and extend the fossil record of Taiwania in North America from the Paleocene (65.5 to 55.8 Ma) to the Middle Albian. These fossils provide a basis for re-assessment of the evolution, paleoecology, and biogeographic history of the genus. The fossil record of Taiwania indicates the genus was rare, but distributed throughout North America and Eurasia from Late Cretaceous to the Pliocene (5.3 to 1.8 Ma) time. The spatial and temporal distribution patterns indicate exchange between North America and Asia occurred throughout the Mesozoic and Cenozoic across the Beringian Corridor. More importantly, the distribution of Taiwania indicates that the genus grew and reproduced under a diverse range of climatic and environmental conditions throughout geologic time, including the cold and unique lighting conditions of the polar latitudes. From a physiological standpoint, the ability of Taiwania to tolerate cold to freezing temperatures and its inability to survive periods of extended darkness during the polar winters if temperatures were above freezing support the idea that polar winter temperatures during the Late Mesozoic and early Cenozoic were below freezing. Comparison of the Alaskan fossils with those of T. cryptomeroides Hayata reveals that in all of the features available for study, the fossils fall within the range of size and morphology seen in T. cryptomeroides and are indistinguishable, at least morphologically, from the living species. The remarkable stasis observed in Taiwania demonstrates that the genus has remained morphologically unchanged since Middle Albian time. Consideration of the paleontological, morphological, and molecular data supports the idea that Taiwania diverged early in the evolution of the Cupressaceae.

Well-preserved fin spines, ornate opercular bones and thick ctenoid scales recovered from the unconsolidated marine sediments of the Cretaceous-Tertiary boundary interval in Upper Freehold Township, New Jersey, USA derive from at least one species of enigmatic euacanthopterygian fish. Within this group the fossils are most similar to corresponding bones of some beryciforms. The fin spines are less than 1.5 cm long, have complex basal articulation structures, and a narrow posterior sulcus extending almost to the distal tip. Most spines have lateral grooves, and some have prominent anterior dentations. A few are attached to broadly keeled pterygiophores. Beryciforms and more basal clades of Acanthomorpha first appear in the Late Cretaceous. The New Jersey fossils may expand the known geographic distribution of beryciforms across the K/T boundary beyond the better known Late Cretaceous beryciforms from the Western Interior of North America, Europe, and the Middle East.

We describe the new species Brachyhypopomus bullocki (Gymnotiformes: Hypopomidae) from the río Orinoco basin of Colombia and Venezuela as well as the Takutu River/rio Branco-rio Negro basin of Guyana and Brazil. Among its congeners, B. bullocki most closely resembles Brachyhypopomus brevirostris (Steindachner, 1868) in possessing an elongated caudal filament which may reach up to 45% TL in reproductive males, in having wide, evenly spaced saddles of pigment over the dorsum connecting to lateral bands of pigment along the abdominal flanks, and in having a mesocoracoid bone. This new species is distinguished from B. brevirostris and other members of the genus by a large eye (15.5–19.2% of head length), a short abdomen usually with 12 pre-caudal vertebrae, and poorly ossified third and fourth branchiostegal rays that are enlarged distally, producing a bulbous appearance of the opercular region. The electric organ discharge waveform of B. bullocki is biphasic, 0.9–1.6 milliseconds in duration, and the pulse rate varies from 20–80 Hz.

New taxon: Brachyhypopomus bullocki Sullivan and Hopkins

Oedemognathus exodon, a monotypic genus and species of Amazonian apteronotid electric fishes, is based on a single specimen with uniquely externalized jaw teeth projecting from a bulbous snout. Recently, many additional specimens of Oedemognathus, all mature males, have been collected in the Amazon by trawling in channels and seining in floating vegetation mats. These new specimens were collected with many monomorphic female, male and immature specimens of Sternarchogiton nattereri, a related and similar species. On this basis we suggested a hypothesis of sexual dimorphism and conspecificity for O. exodon and S. nattereri. Although this idea has been taxonomically accepted by recent authors with treatment of O. exodon as a junior synonym of S. nattereri, the evidentiary basis for this remains unpublished. Herein we present that evidence. In addition to being associated at sexual maturity during breeding season, S. nattereri and O. exodon are closely similar in external and internal morphology, pigmentation, and mitochondrial cytochrome b sequences. Furthermore, we observe that the striking dentition, jaw and snout morphology of Oedemognathus has its developmental origin in mature males that are equal, or nearly so, in size to non-dimorphic S. nattereri.

Four species in the fasciolariid genus Fusinus obtained by Chinese commercial fishing boats are identified and compared with material from the Philippines and Japan. One is here described as new to science, Fusinus marisinicus n. sp. Phenotypic variation in Fusinus salisburyi, F. forceps and F. diandraensis is discussed, and various forms are figured with their intergrades. Further descriptive details of F. diandraensis are given, and new comparisons are made with sympatric congeners including F. perplexus and F. flavicomus.

New taxon: Fusinus marisinicus Callomon and Snyder

Madagascar is widely recognized as a biodiversity hotspot, but the freshwater bivalves have received only limited recent attention. Based upon examination of records from 15 major museums and a literature review, at least nine species of freshwater mussels (Mollusca: Bivalvia: Unionoida) have been reported from either Madagascar or the Mascarene Islands (specifically, Reunion or Mauritius) in the Indian Ocean, east of Africa. The quality of the data, however, is generally poor. Seven of those species records are regarded as either erroneous reports of taxa known from other regions or as nomina dubia. No records from the Mascarenes are considered to be valid. The two remaining species, Etheria elliptica Lamarck 1807 and Unio geayi Germain 1911 (= Coelatura geayi) are both from Madagascar, and the latter is discussed in the context of two alternative hypotheses for the origin of the family Unionidae, nicknamed “Out of Africa” and “Into Africa.” Germainaia gen. nov. is introduced for Unio geayi to emphasize the distinction of that species from other Afrotropical freshwater mussel lineages. The possibility that Germainaia may represent the Hyriidae in Madagascar is discussed, but the new genus is left incertae sedis at the family-level in the absence of complete data.

New taxon: Germainaia Graf and Cummings

We provide descriptions of five species of Chaetopterus and two species of Mesochaetopterus (Annelida: Polychaeta: Chaetopteridae) based on collections during 2001–2007 and observations from the Galapagos Islands, Ecuador. Chaetopterus galapagensis sp. nov. is a large (ca. 18 cm long) worm that inhabits a U-shaped tube in soft sand substrates. It is characterized by 12 – 14 chaetigers in the anterior region and 7–8 teeth on uncini of region A neuropodia. Chaetopterus charlesdarwinii sp. nov. is of intermediate size (2 – 4.5 cm long) with 9 anterior region chaetigers and a characteristic brown band on the lateral side of the ventral shield and posterior side of anterior region notopodia. It inhabits irregularly curved tubes cemented to the underside of rocks. Worms may occur singly or aggregated, with up to 10 worms in a cluster. Chaetopterus aduncus sp. nov. is 8–10 cm in length, and is characterized by 10 – 11 anterior region chaetigers, characteristic J-shaped tube with one blind end, and prominent dorsal bulbous inflations in anterior region chaetigers. Chaetopterus longipes Crossland, 1904 is highly gregarious, frequently forming aggregations of hundreds of worms. It is especially common at the northern islands of Darwin and Wolf. Chaetopterus macropus Schmarda, 1861 is solitary, lives in a U-shaped tube on a sandy bottom, has 9 anterior region chaetigers and no brown bands in region-A. We compared the five Galapagos Chaetopterus species to other Pacific (Japanese and Australian) species of the genus in detail. We confirm the presence of Mesochaetopterus minutus Potts, 1914 in Galapagos, the only chaetopterid previously recorded from the archipelago. Mesochaetopterus ecuadorica sp. nov. is a large (12 – 20 cm long) solitary species with 2 middle region chaetigers, that inhabits a long, nearly straight tube with small perforations at the blind end.

New taxa: Chaetopterus galapagensis Nishi, Hickman, & Bailey-Brock, Chaetopterus charlesdarwinii Nishi, Hickman, & BaileyBrock, Chaetopterus aduncus Nishi, Hickman, & Bailey-Brock, Mesochaetopterus ecuadorica Nishi, Hickman, & Bailey-Brock

The gross morphology of the gas bladder is described, illustrated, compared and categorized among 86 of 88 nominal valid and six undescribed species representing all 31 genera of Doradidae with comments on ontogenetic and taxonomic variation when observed. The putatively basal-most doradids exhibit an unmodified cordiform gas bladder. Derived taxa exhibit an impressive suite of modifications including the addition of a secondary bladder, pronounced reduction of the posterolateral chambers, internal trabeculae, associations with bony capsule-like expansions of the anterior (Weberian) vertebrae, and accessory diverticula varying widely in size, shape, abundance, and distribution, Intra-specific differences are minor, most often reflective of ontogenetic changes especially in large-size species, whereas inter-specific and inter-generic differences are significant, in many cases diagnostic, and suggestive of phylogenetic signal excepting instances of evident convergence such as gas bladder reduction in Rhynchodoras and all but one species of Leptodoras.