The rissooidean family Hydrobiidae Troschel, 1857 is supposedly one of the largest gastropod families with more than 400 recent genera assigned. Due to the limited number of robust anatomical characters in hydrobiids, the high degree of intraspecific variation, the unknown phylogenetic significance of anatomical characters, and the high degree of homoplasy in anatomical characters, its systematic is confusing and phylogenetic relationships within the family and with other rissooidean groups are poorly understood.

We studied fragments of the COI and 18S genes from representatives of 40 genera to determine if the family Hydrobiidae (as defined by Kabat and Hershler, 1993) is monophyletic, if the family Hydrobiidae could be resolved using these genes, and whether the Cochliopidae are a distinct family as previously suggested.

The cluster patterns in the combined 18S COI tree as well as in the individual 18S and COI trees show that the Hydrobiidae of Kabat and Hershler (1993) are polyphyletic. The analyses also confirm previous studies suggesting that the Cochliopidae are a family distinct from the Hydrobiidae. The following subfamilies are tentatively assigned to the Hydrobiidae: Hydrobiinae, Pseudamnicolinae, Nymphophilinae, Islamiinae, and Horatiinae. Three hydrobiid genera, Mercuria, Hauffenia, and Graziana, could not be assigned unambiguously to one of these subfamilies.

The phylogenetic relationships of the families studied are discussed in the light of the available anatomical data and the performance of the two gene fragments used.

Three new species of triviid gastropods are described. Galeatrivia Cate, 1979 is synonymized with Triviella Jousseaume, 1884. Thirteen species named as Trivia or Galeatrivia are transferred to Triviella.

Species novae: Trivellona bealsi (from the Philippines), Triviella immelmani (from South Africa), Trivia marlowi (from Namibia).

Three new species of fossil crane flies are described from Baltic amber (Eocene). Their affinities to other recent and fossil species of the family Pediciidae are discussed.

Species novae: Tricyphona aurata, T. lepesca, T. residua.

Seven new species of Limoniidae are described from Mongolia: Cheilotrichia (Empeda) tenuifurca (Hovsgol Province), Dicranomyia (Idiopyga) sineloba (Dornad Province), Dicranomyia (Melanolimonia) monkhtuyae (Hovsgol Province), Gonomyia (Gonomyia) curvispina (Bulgan Province), Limnophila (Limnophila) chinggiskhani (Hovsgol and Tov Provinces), Phylidorea (Macrolabina) temelskin (Hosvgol and Tov Provinces) and Symplecta (Symplecta) rotundiloba (Hovsgol Province). Descriptions and illustrations of the distinguishing morphological features, including wing venation, genitalia and antenna, are provided, with a discussion on distinguishing each of these newly described species from other similar species. Illustrations of the holotype of Symplecta tripilata (Alexander) (Kashmir) are presented for comparison with Symplecta rotundiloba. Illustrations of the male and female genitalia of Phylidorea nigronotata (Siebke) are presented for comparison with Phylidorea temelskin. Habitat information for each species is presented.

Species novae: Cheilotrichia (Empeda) tenuifurca, Dicranomyia (Idiopyga) sineloba, Dicranomyia (Melanolimonia) monkhtuyae, Gonomyia (Gonomyia) curvispina, Limnophila (Limnophila) chinggiskhani, Phylidorea (Macrolabina) temelskin, Symplecta (Symplecta) rotundiloba.

The description of a new species of the woodroach Cryptocercus kyebangensis Grandcolas from South Korea offers the opportunity to bring comparative information within the genus. This species, though morphologically very similar to other East Asian and North American species, presents conspicuous differentiation of both ribosomal genes (sequenced fragments of 12S and 16S) and chemical blends from tergal glands (proportions of linalyl acetate and the alcohol 4, 6, 8-trimethyl-7, 9-undecadien-5-ol, compounds previously identified in females originating from North America). A phylogenetic reconstruction involving Blatta orientalis as an outgroup, Therea petiveriana as a polyphagid relative, C. kyebangensis and 17 North American Cryptocercus populations showed that C. kyebangensis stands as a sister-group of North American Cryptocercus, thus suggesting that one beringian vicariance has taken place in the early differentiation of the genus. Using sequence divergences within the framework of the molecular clock leads to comparable datation estimates for both ribosomal genes, ranging between Miocene and Pliocene for the whole history of the genus Cryptocercus, therefore congruent with previous phylogenetic biogeographical estimates. This new set of data for this East Asian species supports heterobathmy in the genus Cryptocercus and argues against the misleading “primitive taxon” concept.

Species nova: Cryptocercus kyebangensis Grandcolas.

This survey of Santee Cave is the first inventory of cavernicolous invertebrates in a South Carolina cave. Both aquatic and terrestrial habitats were surveyed. Sixty-two cavernicolous species were collected, including eight annelids, six mollusks, 46 arthropods, and four slime molds. Faunal richness was comparable to, or greater than, that of similar caves in Florida and Georgia.

Sorubim maniradii, a new species, is described on the basis of 29 specimens from the middle and upper Amazon River Basin of Bolivia, Brazil, Ecuador, and Peru. This species is similar in morphology to S. lima and S. elongatus, but is distinguished from all congeners by its diffuse (versus conspicuously black) lateral stripe and high gill raker count (31–37 versus 13–23). It occurs sympatrically and syntopically with S. lima and S. elongatus.

Species nova—Sorubim maniradii.

Identification of diatom frustules, a vital step during ecological analyses, is greatly influenced by the magnification at which samples are examined. The striking differences between Light Microscopy (LM) and Scanning Electron Microscopy (SEM) reveal inconsistencies in the identification of diatoms at low magnifications. These inconsistencies hinder comparative analyses between data sets collected by several research centers and may be hiding information of potential value in the assessment of ecosystem health. Additionally, SEM research has had a marked impact on diatom taxonomy rendering traditional identification methods insufficient for recognition of newly created taxa. Many diagnostic features of small representatives of these newly erected taxa can not be recognized even at higher LM magnifications. The consequent lack of taxonomic resolution at the LM level may be leading to overestimation of geographical distributions, ranges of tolerance to environmental parameters, and optimal conditions for growth. Qualitative aspects of the differences between LM and SEM approaches are discussed in the present paper.

Several fragilarioid diatoms were found in surface sediment samples from Connecticut (U.S.A.) as part of a paleolimnological study on a set of 60 freshwater lakes. Observation of acid-digested material under scanning electron microscopy (SEM) revealed morphological variants of Staurosira and Stauroforma absent or seldom illustrated in the literature. Morphological variants of Staurosira reported here could be misidentified during routine ecological analyses due to limitations at the light microscopy (LM) level and because identification keys do not incorporate descriptions of such morphs. SEM observations also revealed the existence of two new fragilarioid taxa in 3 of the 60 Connecticut lakes. One of the new taxa is described here as Pseudostaurosira trainorii sp. nov. and appears to be distributed in fresh and brackish waters. For the second taxon, Pseudostaurosiropsis, nov. gen., is described based mainly on areolar and closing plate structure, features that are visible only at higher SEM magnifications. Pseudostaurosiropsis connecticutensis, sp. nov., with three freshwater populations in Connecticut, is the type species. Morphological aspects and ecology of the newly described taxa, as well as their relationship with other fragilarioid diatoms are discussed.

Genus et species novae: Pseudostaurosiropsis, gen. nov.; P. connecticutensis, sp. nov.; Pseudostaurosira trainorii, sp. nov.

The two species of Pleurosigma described by G. Shadbolt have been critically examined in the type material with LM and with SEM for specimens conforming to the types in LM. A comparison of P. inflatum Shadbolt and P. naviculaceum Brébisson did not reveal any specific difference; the former taxon has priority while the latter is designated a synonym. The protologue of P. diverse-striatum Meister matches that of P. inflatum, but new findings validate its separate status. Pleurosigma diverse-striatum differs from other members of the genus by its areolar morphology. Its status as a synonym of P. aequatoriale Cleve will be clarified in a future paper. Pleurosigma validum Shadbolt is shown to be a synonym of P. rigidum W. Smith. Lectotypes are designated for Pleurosigma inflatum Shadbolt, 1853, Pleurosigma naviculaceum Brébisson, 1854, and Pleurosigma validum Shadbolt, 1853; and Pleurosigma diverse-striatum Meister, 1934, is typified.

The Diatoms of the United States has been printed in two volumes: Volume 1 (1966, and a second printing in 1978 with minor emendations); and Volume 2, Part 1 (1975). Addenda and corrigenda for these volumes and printings are provided here. The literature cited in the Systematic Section of these volumes, originally intended to be collated in a final publication, is published here.