Long-term observations of a marine planktonic plicate Thalassiosira species, T. cedarkeyensis Prasad, from the Gulf coasts of Florida, Alabama, and Mississippi and the Atlantic coasts of Florida and Georgia demonstrate its wide occurrence in the southeastern United States and its ability to form extensive blooms. We also report for the first time its ability to form typical Thalassiosira chains, linking sibling cells by threads of chitin. A closely related and co-occurring diatom, T. livingstoniorum, is described on the basis of investigations conducted during 2000–2011 as a new species from many localities in Apalachee Bay on the Gulf coast and Indian River Lagoon on the Atlantic coast of Florida. It differs from T. cedarkeyensis in areola density, presence of continuous cribra on loculate areolae, arrangement and distribution of valve processes, and the number of satellite pores surrounding the valve-face fultoportulae. We have not yet found any evidence of chain formation in T. livingstoniorum. Thalassiosira cedarkeyensis and T. livingstoniorum can be easily distinguished in Naphrax-mounted preparations in light microscopy (LM), and they represent two different groups (lineages?) of plicate species with reference to internal cribrum structure of the loculate areolae. Their differences may justify placement in two different genera. Although T. cedarkeyensis (which has individual cribra on the proximal siliceous layer like T. hyperborea) is abundant and widespread on the Gulf and Atlantic coasts of the southeastern United States, T. livingstoniorum (which has continuous cribra like T. lacustris) has been found, thus far, only in Florida coastal waters. Comparisons are made between these two species and the other morphologically similar extant and extinct plicate species. Thalassiosira livingstoniorum and T. cedarkeyensis, although widespread and frequently encountered during warmer months, may be easily overlooked sources of primary production in the nutrient-rich northeastern Gulf of Mexico.

A new diatom species, Tabellaria vetteri, is described from North-Central Pennsylvania. Unlike other representatives of the genus Tabellaria Ehrenberg, the new species lacks rimoportulae, the central part of its valve is internally thickened, and all girdle bands are open. Other characters, such as shape of the frustule, numerous ligulate girdle bands bearing septa, uniseriate striae with small poroid areolae, large apical pore fields, and simple spines fit the current concept of this genus. The new species is found so far only in two small soft-water streams and is especially abundant on sand.

Frustulia weinholdii and Frustulia neomundana are unusual species of Frustulia that possess a set of incomplete longitudinal ribs and unilaterally deflected proximal-raphe ends. This peculiar combination of traits clearly contrasts these species from most congeners, including the generitype. We reexamined material investigated by J. H. Wallace in order to determine diversity within this species group. We compared the specimens from his South Carolina sample with morphologically similar specimens collected in Hawaii, USA. Our investigation of specimens from both Hawaii and South Carolina with light and scanning electron microscopy revealed a previously undocumented amount of morphological diversity in species from the F. weinholdii complex. We describe this morphological variation and present three new species, F. capitata, F. latita, and F. soror, which can be distinguished from similar species by general valve shape, striae density, and longitudinal rib appearance. Presence of incomplete longitudinal ribs and curved raphe ends may be features used to distinguish this group of species from other, typical Frustulia taxa.

Large raptors have complicated primary flight feather molt cycles because they cannot afford to be grounded for any significant amount of time. Ospreys (Pandion haliaetus) use Staffelmauser molt, the replacement of remiges in waves, allowing for constant mobility. Since their remiges are always in a molting cycle, Ospreys may grow feathers on their breeding and wintering grounds, each location providing its own distinctive stable isotopic signature. Herein we demonstrate that multiple analyses of carbon and nitrogen stable isotopes from several locations along the primary flight feathers of Mid-Atlantic Ospreys document the location of the individual during feather growth. Any previous studies regarding Ospreys feather growth locations were carried out through wear studies, a highly subjective practice. We document three distinct signatures, a breeding ground signature for the Chesapeake and Delaware Bays, and two wintering ground signatures, one in the Caribbean and one in northern South America. By analyzing multiple locations along each feather, a technique not executed before, we also document the continuation of molt during migration in a few specimens.

Three new species of Limoniidae are described from specimens collected during the fieldwork of the Mongolian Aquatic Insect Survey Project in north-central Mongolia: Gonomyia (Gonomyia) oyunaae (Bulgan, Hovsgol and Selenge Provinces), Molophilus (Molophilus) virginijae (Selenge and Tov Provinces), and Phyllolabis mongolica (Tov Province). Descriptions and illustrations of the distinguishing morphological features are provided. Habitat information for each species is presented.

The land slug Meghimatium pictum (Stoliczka, 1873), native to China, is recorded for the first time in Brazil. This is also the first record of a species of the eastern Asiatic genus Meghimatium on the American continents. The species was identified using morphological criteria and analysis of the cytochrome oxidase subunit I, COI. Our records indicate this species is widely distributed in southern and southeastern Brazil, in the States of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul, in disturbed and natural areas. We morphologically characterize M. pictum (external characteristics, reproductive system, jaw and radula) and provide some biological information based on field observations. We also discuss when M. pictum was probably introduced, from whence it came, possible pathways of introduction, and its characteristics as an invasive species and potential agricultural pest.

The availability and authorship of Scalaria borealis Lyell, 1841 and Scalaria borealis Gould, 1852 have been subject of considerable debate. Both names are shown to be available and the latter, being preoccupied, should be called Opalia wroblewskyi (Mörch, 1875). Scalaria borealis Lyell, 1841 is confirmed as the type species of Acirsa Mörch, 1857; its current name is Acirsa borealis (Lyell, 1841). Lectotypes are designated for both species.

A new species of Lienardia (Conoidea: Clathurellidae) is described from the Philippines and Spratly Islands and compared to L. giliberti Souverbie, 1874, with which it has been confused. The species is routinely found in lumun-lumun nets in the southern Philippines, particularly in the Panglao area, in depths of 50 and HO m. Correlations between radular morphology and shell coloration support maintaining Lienardia and Clathurella as distinct genera.

Ossancora, new genus, is diagnosed within Doradidae by having the unique combination of posterior coracoid process approximately as long as posterior cleithral process in adults, posterior cranial fontanel occluded, long maxillary barbel with smooth elongate fimbriae, and teeth present on dentary and premaxilla. A similarly long posterior coracoid process is found in only one other doradid species, Trachydoras paraguayensis, which is distinguished, as are its congeners, from Ossancora by having a small posterior cranial fontanel retained in adults, a relatively short maxillary barbel with stout fimbriae, and edentulous jaws. Three nominal species are recognized as valid and redescribed in Ossancora: Doras punctatus Kner 1853, in both the Amazonas and Paraná-Paraguay basins, Oxydoras eigenmanni Boulenger 1895, in the Paraguay basin, and Doras fimbriatus Kner 1855 in the Amazonas basin. The younger name Doras fimbriatus Kner 1855 is considered valid as a nomen protectum according to Article 23.9 of the ICZN, and its older synonym, D. loricatus Kner 1853 qualifies as a nomen oblitum. A fourth new species, Ossancora asterophysa, is described and diagnosed in part by a gas bladder morphology that is distinctive among congeners. Three species, O. eigenmanni, O. fimbriata and O. asterophysa, form a monophyletic group based on three shared characteristics: smooth elongate fimbriae inserted in more than one row, one dorsally and one ventrally, along anterior margin of maxillary barbel (uniquely derived among Doradidae), elongate fimbriae on mental barbels, and anterior nuchal plate reduced, not sutured to epioccipital (latter two features uniquely derived among Ossancora). Ossancora is typical of lowland floodplain lakes and river channels, and its occurrence in the both the Amazonas and Paraná-Paraguay supports a historical link between these two basins. A key to species and detailed anatomical descriptions are provided. Type specimens are discussed and lectotypes are newly designated for Oxydoras eigenmanni Boulenger 1895, D. fimbriatus Kner 1855, and Doras (Corydoras) punctatus Kner 1853, respectively.

Existing phylogenetic hypotheses on the intrarelationships of South American pimelodid catfishes are incompletely resolved and based almost entirely on morphological data. This study analyzed more than seven kilobases of aligned nucleotide sequences from the rag1 and rag2 nuclear genes, and the 12S, 16S and cytochrome b mitochondrial genes for 52 nominal and five undescribed pimelodid species representing 27 of 31 extant genera. Results of Bayesian likelihood and maximum parsimony analyses of the combined sequence data consistently recover 40 monophyletic pimelodid clades above the species level.

The basal lineages of Pimelodidae are Steindachneridion and Phractocephalus that are serially, or together as small clade, sister to all other members of the family. Leiarius and the nominal Perrunichthys perruno are sister to the neopimelodines, a clade comprised of the remaining pimelodids divided into two major lineages: the sorubimines and the Pimelodus ornatus-Calophysus-Pimelodus (OCP) Clade. Sorubimines include seven well-supported units whose interrelationships are poorly resolved: Sorubim, Pseudoplatystoma-Sorubimichthys Clade, tribe Brachyplatystomatini, Platysilurus-Platystomatichthys Clade, Hypophthalmus, Zungaro and Hemisorubim. In conflict with morphological evidence, the molecular data do not support monophyly of the genus Brachyplatystoma. However, the subgenus Malacobagrus (B. rousseauxii, B. capapretum, B. filamentosum) and the sister species pair B. juruense and B. platynemum are each recovered as monophyletic.

The OCP Clade comprises nominal Pimelodus ornatus that is sister to the Calophysus-Pimelodus Clade in turn split into the calophysines and pimelodines. Calophysines include a monophyletic Calophysus Group (Calophysus, Aguarunichthys, Luciopimelodus, Pinirampus, Pimelodina) and the Megalonema-Cheirocerus Group. Intrarelationships of the Calophysus Group recovered with molecular data are congruent with relationships based on morphology. Placement of Cheirocerus sister to Megalonema is unexpected but well supported by molecular data.

Pimelodines include the Exallodontus-Pimelodus altissimus Group and Pimelodus Group. The former correspond to the “long-finned” pimelodids including Exallodontus sister to an undescribed miniature species from the Amazon, and those sister to undescribed species of Propimelodus. An undescribed species related to nominal Pimelodus altissimus is the sister to nominal Duopalatinus peruanus. Nominal Pimelodus pictus is sister to remaining members of the Pimelodus Group that in turn contains three subclades: Iheringichthys plus Parapimelodus, Pimelodus maculatus plus P. albicans, and P. blochii including P. argenteus. Pimelodus coprophagus is unresolved among the P. maculatus and P. blochii groups. A generic reclassification of the species now assigned to polyphyletic Pimelodus is needed based on more complete taxon sampling and character evidence.

A modest sampling of multiple specimens from thirteen pimelodid species permitted a first examination of their genetic diversity within and across the major South American river basins. The rag and mitochondrial genes examined here show little divergence between distant allopatric populations of Pinirampus pirinampu, Brachyplatystoma vaillantii, B. rousseauxii, B. filamentosum and B. juruense. However, specimens representing allopatric populations of five nominal species are as divergent as distinct congeneric species: Pimelodus blochii, P. ornatus, P. pictus, Platysilurus mucosus and Megalonema platycephalum.

We analyze a new sample of very small Bothriolepis from the Catskill Formation (Upper Devonian, Famennian Stage) in Tioga County, Pennsylvania, USA. The material was collected in a series of rock slabs, each of which carries as many as thirty-one individuals in densely-packed groups with little to no overlap and with a preferred orientation. Although the taxonomy of Catskill Bothriolepis does not allow for a species diagnosis, morphometric comparison between the new sample and a growth series of Bothriolepis canadensis supports the juvenile status of the individuals in the new Catskill sample. By comparing the new material with other worldwide occurrences of small antiarchs, we recognize anatomical features that indicate juvenile status in antiarchs, including a large median ventral fenestra lacking a median ventral skeletal element, especially large medial serrations on the pectoral appendages, and a strongly convex rostral margin of the postpineal element. The geological and taphonomic context of the new material suggests death events of Bothriolepis hatchlings due to anoxia and desiccation in marginal aquatic environments. We highlight the implications for reproductive strategy in antiarchs.