The recent discovery and description of an unusually puzzling catfish, Kryptoglanis shajii Vincent and Thomas (2011) from ground and surface waters in Kerala State, southwestern, peninsular India, added an unresolved taxon to the order Siluriformes. Here we use high-resolution X-ray computed tomography (HRXCT) and X-radiography to illustrate, describe and compare the bony skeleton of Kryptoglanis with the objective of determining its phylogenetic position.

Several characteristics of Kryptoglanis are strongly modified and structurally complex, setting this catfish apart from other siluriforms. Striking examples are its greatly shortened mesethmoid with overlapping frontals; non-tubular nasal bone; absence of the infraorbital lateralis sensory canal and canal bones but with an apparent antorbital bone; the flat and expansive orbitosphenoid; the vaulted supraoccipital-Weberian neural arch joint; the fenestrated occipital wall; the upwardly flexed occipito-vertebral joint; three pairs of elongated accessory processes off the compound Weberian vertebra; a unique exoccipital process for attachment of the transscapular ligament; hyomandibular-sphenotic ball and socket articulation; a serially notched anterior ceratohyal; and a novel posttemporo-supracleithum joint with the fourth transverse process. Some of these apparent autapomorphic features may eventually be found in some other siluriforms and judged to be informative on phylogenetic relationships. Presently, however, we have identified a few features that support the placement of Kryptoglanis in the Siluroidei (the presence of a posterior nostril barbel and position of the pterosphenoid along the anterior margin of the trigeminofacial foramen), and therein, as the sister lineage to family Siluridae (the nodular form and small size of the autopalatine).

This study examines the distribution and ecology of the morphologically complex genus Calothrix, which contains species particularly hard to identify due to morphological variability with changing water conditions. Up to a dozen species have been reported previously in US freshwater environments. Using literature review to establish previously reported occurrences and the extensive dataset from the Environmental Protection Agency National River and Streams Assessment, this study mapped the current confirmed distribution of 7 species in United States rivers and streams. Results from data analysis showed Calothrix spp. occurring in 42 States and establish its occurrence in both flowing and standing, typically alkaline or neutral waters. Ecological traits exhibited by individual species included C. fusca (Kützing) Bornet & Flahault indicating pH may be a limiting factor, with this species preferring more alkaline waters. In addition, conductivity levels influenced filament structure. Data indicates that Calothrix epiphytica West & G.S. West responds to higher light availability and is also influences by turbidity levels. This study expands our ecological knowledge of species belonging to the genus Calothrix, begins to document the current distribution of these species and the morphological data presented represent the first metapopulation data summary for US Calothrix distribution. The study also confirms the need for a polyphasic approach when studying this group and suggests that molecular data be incorporated into continent-wide studies in the future.

Twelve new diatom species are described from remote locations in the western United States: Cymbella blinnii sp. nov., Cymbopleura maggieae sp. nov., Encyonema drakei sp. nov., E. pentoniae sp. nov., E. willeyorum sp. nov., Frustulia esandalliae sp. nov., Gomphonema darwinii sp. nov., G. evolutionensis sp. nov., Muelleria agnellus sp. nov., M. spauldingiae sp. nov., M. tetonensis sp. nov., and Navicula harmoniae sp. nov. Descriptions are supported by LM images showing size diminution in the type populations and by SEM images. Type populations of the new species are from California (3 species), Colorado (3), Montana (2), Oregon (2), Washington (1), and Wyoming (1). All of the type materials for these new species were collected by unpaid citizen volunteers. This paper reviews other new species and significant new distribution records produced by volunteer collections. It also discusses the process of engaging citizen volunteers in diatom collection and the value of citizen collections in building diatom herbaria, in cataloging diatom biodiversity, and in expanding our knowledge of diatom biogeography, especially in remote regions with difficult access.

The holotype specimen of Atlantochelys mortoni, a large sea turtle of Cretaceous age, consisted of only the proximal half of a humerus. Remarkably, the distal half of the same bone has now been recovered, 163 years after the holotype was first described. Besides clarification of the type locality, the size of the complete humerus suggests that this is among the largest turtles known. Circumstances of the discovery suggest that multiple periods of deposition and erosion took place at the discovery site.

The type series of Squalius squalus Bonaparte (1837) includes two species. A lectotype is designated to fix the name to the species currently recognised under this name.

Procerusternarchus pixuna, a new genus and species of hypopomid gymnotiform, is described from several tributaries of Negro River, Amazonas State, Brazil. The new genus is included in the tribe Microsternarchini with the genera Microsternarchus and Racenisia based on a phylogenetic analysis of 41 anatomical, morphometric, meristic, and electric organ discharge variable characters. The new taxon is distinguished from Microsternarchus and Racenisia by the apomorphic presence of a deep, enlarged myogenic electric organ, an electric organ discharge with a greatly reduced negative phase and the plesiomorphic condition of a fully-scaled body, whereas scales are absent from the upper back of Microsternarchus and Racenisia.

In the Appendix to his classic two-volume work, “The Natural History of Carolina, Florida and the Bahama Islands…”, Mark Catesby (1747:19, Pl. 19) described and illustrated the doradid catfish “Cataphractus Americanus”. The names “Cataphractus” and “Cataphractus Americanus” are not available from pre- and post-Linnaean editions of Catesby's work (i.e., Catesby, 1747; 1754; 1771) including Edwards' (1771b) Catalogue appended to the third edition. Linnaeus (1758), however, cited Catesby's “Cataphractus Americanus” in his description of Silurus cataphractus, a species currently valid in Acanthodoras Bleeker 1862. Based on this study of Catesby's original description and illustration, his “Cataphractus Americanus” is newly assigned to Platydoras Bleeker 1862, rendering polytypic the type series of Silurus cataphractus Linneaus 1758. Consequently, BMNH 1853.11.12.193 [ex. Museo Gronovii] is here designated the lectotype of Silurus cataphractus Linneaus 1758, and its objective synonyms Cataphractus americanus Bloch & Schneider 1801, and Cataphractus americanus Lacépède 1803.

Nemadoras cristinae is described from the upper Amazonas/Solimões and Madeira basins in Brazil, Colombia and Peru, with additional specimens from the upper Meta (Orinoco basin), Colombia, tentatively treated as conspecific. Nemadoras cristinae is distinguished from congeners by having 3–9 premaxillary teeth in approximately two rows in juveniles and adults, outermost teeth weakly spatulate and innermost more acicular (vs. premaxillary edentulous in adults of all congeners and limited to 1–6 acicular teeth in juveniles of N. elongatus, N. humeralis, N. leporhinus and N. ternetzi); and mental barbels with extremely elongate (filiform) papillae, length of longest papillae about 4–7 times its width at base (vs. papillae shorter, length of longest <3 times its width at base). Nemadoras cristinae most closely resembles N. leporhinus, but is further distinguished from that species by having shaft and primary fimbriae of maxillary barbel smooth (vs. outer margin of shaft and margins of primary fimbriae with distinct secondary fimbriae). Nuptial specimens of N. cristinae exhibit sexual dimorphism; in males the pungent dorsal spine is greatly prolonged by a soft, flexible tip approximately 19.8–23.9% of the total dorsal spine length (vs. 5.3–9.4% in females). The sturdy, spatulate teeth in the upper and lower jaws of N. cristinae are evidently effective tools for raking caddisfly larvae from their attached substrates, as gut contents were dominated by cases and larval remnants of Nectopsyche (Leptoceridae). The six other species of Nemadoras are redescribed, the monophyly of the genus is discussed, and an identification key is provided. Detailed observations on the mesethmoid and infraorbital bones and associated sensory canal are reported for Nemadoras and compared to other species of fimbriate-barbel doradids.

Seven new species of Thala are described: T. abelai and T. merrilli (type locality Guam, Mariana Islands), T. evelynae and T. suduirauti (Philippines), T. kilburni and T. pallida (Bassas da India Reef, Mozambique Channel) and T. ruggeriae (Tanzania) and their geographic ranges established. Lectotypes are selected for T. exilis (Reeve, 1845), T. roseata (A. Adams, 1855), T. fusus (Souverbie, 1876), and T. ogasawarana Pilsbry, 1904, and T. fusus is synonymized with T. mirifica (Reeve, 1845). The range of T. lillicoi Rosenberg & Salisbury, 2007 is extended to Kwajalein from Hawaii. Live animals of six species are illustrated. Microsculpture of 14 species is illustrated with scanning electron microscopy.