Differential Transmission of the Genospecies of Borrelia burgdorferi Sensu Lato by Game Birds and Small Rodents in England

The genetic diversity of Borrelia burgdorferi sensu lato was assessed in a focus of Lyme borreliosis in southern Britain dominated by game birds. Ticks, rodents, and pheasants were analyzed for spirochete infections by PCR targeting the 23S-5S rRNA genes, followed by genotyping by the reverse line blot method. In questing Ixodes ricinus ticks, three genospecies of B. burgdorferi sensu lato were detected, with the highest prevalences found for Borrelia garinii and Borrelia valaisiana. B. burgdorferi sensu stricto was rare (<1%) in all tick stages. Borrelia afzelii was not detected in any of the samples. More than 50% of engorged nymphs collected from pheasants were infected with borreliae, mainly B. garinii and/or B. valaisiana. Although 19% of the rodents harbored B. burgdorferi sensu stricto and/or B. garinii in internal organs, only B. burgdorferi sensu stricto was transmitted to xenodiagnostic tick larvae (it was transmitted to 1% of the larvae). The data indicate that different genospecies of B. burgdorferi sensu lato can be maintained in nature by distinct transmission cycles involving the same vector tick species but different vertebrate host species. Wildlife management may have an influence on the relative risk of different clinical forms of Lyme borreliosis.     

Molecular Evidence for Multiple Origins of the European Spined Loaches (Teleostei,Cobitidae)

We present a phylogenetic investigation of the Northern Clade, the major monophyletic clade within the freshwater fish family Cobitidae, one of the most prominent families of freshwater fishes found in Asian and European waters. Phylogenetic reconstructions based on the cytochrome b and RAG-1 genes show the genera Microcobitis, Sabanejewia, Koreocobitis and Kichulchoia as monophyletic groups. These reconstructions also show a Cobitis sensu lato and a Misgurnus sensu lato group. The Cobitis sensu lato group includes all species of Cobitis, Iksookimia, Niwaella and Kichulchoia, while the Misgurnus sensu lato group includes Misgurnus, Paramisgurnus and Koreocobitis. Although the monophyly of both the Cobitis sensu lato and Misgurnus sensu lato groups is supported, relationships within the groups are incongruent with current generic definitions. The absence of monophyly of most genera included in the Cobitis sensu lato group (Cobitis, Iksookimia and Niwaella) or their low genetic differentiation (Kichuchoia) supports their consideration as synonyms of Cobitis. Molecular phylogenies indicate that the Asian species of Misgurnus experienced a mitochondrial introgression from a lineage of Cobitis. We also find two nuclear haplotypes in the same Cobitis species from the Adriatic area that, in the absence of morphological differentiation, may indicate molecular introgression. Most lineages within the Northern Clade consist of species found in East Asia. However, some lineages also contain species from Europe and Asia Minor. The phylogenetic relationships presented here are consistent with previous studies suggesting an East Asian origin of the Northern Clade. According to the current distributions and phylogenetic relationships of the Misgurnus sensu lato and Cobitis clade lineages, particularly of M. fossilis and C. melanoleuca, the range expansion of East Asian species into Europe was most likely via Siberia into Northern and Central Europe. Phylogenetic analyses also show that the Cobitis sensu lato group consists of two clear subgroups (I and II), each presenting geographical differences. Subgroup I is distributed exclusively in East Asian drainages with an Eastern European offshoot (C. melanoleuca), whereas Subgroup II includes species widespread throughout Europe (including the Mediterranean), Asia Minor, the Black Sea and the Caucasus, with some lineages related to species restricted to East Asia.     

Karyological studies on Spanish Boraginaceae: Lithospermum L. sensu lato

LUQUE, T. & VALDÉS, B., 1984. Karyological studies on Spanish Boraginaceae: Lithospenum L. sensu lato . All of the Spanish taxa of Lithospermum L. sensu lato (Lithospermum sensu stricto, Neatostema, Buglossoides and Lithodora ), with the exception of Buglossoides gartonii (Bentham) I. M. Johnston, have been studied karyologically. The karyological characters allow the separation of three groups which do not correspond exactly with the morphological limits of the four genera actually recognized for Spain within Lithospermum sensu lato .
Se estudian cariológicamente los taxones españoles de Lithospermum L. sensu lato (Lithospennum sensu stricto, Neatostema, Buglossoides y Lithodora ), salvo Buglossoides gastonii (Bentham) I. M. Johnston. Por los caracteres cariológicos se pueden separar tres grupos cuyos límites no coinciden exactamente con los de los cuatro géneros actualrnente reconocidos para España dentro de Lithospcnum sensu lato .     

Loxocorone,a new genus of the family loxosomatidae (Entoprocta: Solitaria), with descriptions of two new Loxomitra (sensu stricto) and a new Loxocorone from Okinawa,the Ryukyu Archipelago,Japan

The type species of Loxomitra Nielsen, 1964, L. kefersteinii (Claparède, 1867), has following characters: A) the buds have a pair of terminal wings at the base of the stalk, and B) the liberated buds crawl on the substratum by attaching the two terminal wings to the substratum and twisting the whole body. By contrast, some other members of the genus have following characters: A') the buds lack the terminal wings but have a foot with foot groove, and B') the liberated buds glide over the substratum using the foot with foot groove. I thus propose to divide Loxomitra (sensu lato) into two genera- Loxomitra (sensu stricto) characterized by A) and B), and Loxocorone gen. nov. by A') and B'). I also describe two new Loxomitra (sensu stricto), L. mizugamaensis sp. nov., and L. tetraorganon sp. nov., and one new Loxocorone, L. allax sp. nov. from the Ryukyu Archipelago, Japan. All of the currently recognized species of the Loxomitra (sensu lato) are reviewed to specify their generic allocations in response to the above change.     

Reconstruction of phylogenetic relations of Ponto-Caspian gobies (Gobiidae, Perciformes) based on mitochondrial genome variation and some problems of their taxonomy

Phylogenetic relations of Ponto-Caspian gobies in the context of different taxonomic hypotheses have been studied based on the analysis of variations in cytochrome b gene. Evidence for the paraphyly of the genus Neogobius sensu lato, represented by two independent phyletic lineages that should be treated as separate genera Neogobius s. stricto (includes a species group of N. melanostomus-N. fluviatilis-N. caspius) and Ponticola, has been provided. It has been demonstrated that the Racer goby N. gymnotrachelus refers to the latter genus. It is proved that the Grass goby Gobius ophiocephalus belongs to the genus Gobius s. stricto.     

广义竹叶青蛇属Trimeresurus (sensu lato)的分类和系统学研究进展

广义的竹叶青蛇属于Trimeresurus(sensu lato)包含有40多个物种,广泛分布在南亚和东南亚国家和地区。目前,该类群已经相继被划分为6个属：Trimeresurus(sensu stricto)、Tropidolaemus、Ovophis Protobothrops,Triceratolepidophis,Zhaoermia本文从形态、细胞以及分了系统学等方面对Trimeresurus(sensu lato)的分类和系统学研究进行综述。     

Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Francisella tularensis and their co-infections in host-seeking Ixodes ricinus ticks collected in Serbia

To evaluate the prevalence rate of tick-borne bacterial pathogens, unfed adult Ixodes ricinus ticks were collected from vegetation in 2001, 2003, and 2004 at 18 localities throughout Serbia. A total of 287 ticks were examined by PCR technique for the presence of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Francisella tularensis. The highest prevalence rate was that for B. burgdorferi sensu lato (42.5%), followed by A. phagocytophilum (13.9%) and F. tularensis (3.8%). The presence of five B. burgdorferi sensu lato genospecies, namely, B. burgdorferi sensu stricto, B. afzelii, B. garinii, B. lusitaniae, and B. valaisiana was identified by restriction fragment length polymorphism (RFLP) analysis. The most frequent B. burgdorferi sensu lato genospecies was B. lusitaniae, followed by B. burgdorferi sensu stricto. Co-infection by B. burgdorferi sensu stricto and B. lusitaniae was frequently observed. Co-infection by B. burgdorferi sensu lato and A. phagocytophilum and co-infection by B. burgdorferi sensu lato and F. tularensis appeared in 24 ticks. Sequencing of p44/msp2 paralogs of Serbian A. phagocytophilum showed that they were unique and distinct from those of A. phagocytophilum in US and UK. This is the first report of B. garinii, B. lusitaniae, B. valaisiana, as well as A. phagocytophilum and F. tularensis infected ticks in Serbia. These findings indicate a public health threat in Serbia of tick-borne diseases caused by B. burgdorferi sensu lato, A. phagocytophilum and F. tularensis.     

Loss of plasmids of Borrelia burgdorferi sensu lato during prolonged in vitro cultivation

In the present study we analyzed stability of plasmid content in 34 Borrelia strains of three different species (13 Borrelia afzelii, 10 Borrelia garinii and 11 Borrelia burgodorferi sensu stricto) using pulse field gel electrophoresis (PFGE). During long-term in vitro cultivation consisting of 50 passages, plasmid loss was established in 46% of B. afzelii, 40% of B. garinii and 36% of B. burgdorferi sensu stricto strains. Loss of plasmids occurred as early as between the 5th and 10th passage, affected only plasmids in the range 9-41 kb but not plasmids in the range 50-68 kb and manifested with the loss of one to up to three plasmids.     

Phylogenetic taxonomy of Hymenochaete and related genera (Hymenochaetales)

Species delimitation in Hymenochaete sensu lato was evaluated based on partial nucLSU rDNA sequences, isoenzyme analyses and morphological data. Analyses of LSU data revealed Hymenochaete sensu stricto and Pseudochaete as distinct monophyletic genera. Transfer of Hydnochaete olivacea into genus Pseudochaete and Dichochaete setosa into genus Hymenochaete (as H. resupinata) was supported by the results of molecular analyses. A new species Hymenochaete koeljalgii from Tanzania was described. The species of genus Hymenochaete sensu stricto were divided into four well-supported clades possessing no distinctive morphological characters.     

On the origin systematic position of the calcareous-shelled inarticulate brachiopods

Available data on the anatomy, ontogeny embryology of Brachiopoda ( sensu lato ) suggest that this Phylum in the traditional view is in fact a clade of organization includes two stocks of lophophorate organisms of quite different origins. Their rank does not correspond to existing Class divisions. The phosphatic-shelled in articulates are regarded as a separate Class Lingulata. The Phylum Brachiopoda ( sensu stricto ) is restricted to the calcareous-shelled inarticulate articulate lineages. Ancestors of the calcareous-shelled brachiopods probably differentiated from the protolophophorates before the radiation of the other lophophorate stocks took place. The articulation of the valves appeared independently in several lineages during the early stages of brachiopod evolution.     

CLADISTICS AND FAMILY LEVEL CLASSIFICATION OF THE GENTIANALES

Abstract— The most recent classification of the angiosperm order Gentianales (Thorne, 1992) includes four principal families: Apocynaceae, Gentianaceae, Loganiaceae, and Rubiaceae. Ever since Bentham (1857) the status of Loganiaceae has been questioned, and several segregates of that family have been proposed both before and after his treatment. In this study we present cladistic results that show Loganiaceae, sensu lato, to be a paraphyletic group definable only by plesiomorphies, with members showing closest relationships to other families of the order. As the impact of different character-state representations of polymorphic terminals remains largely untested, our morphological and phytochemical data were analysed both with restricted polymorphism coding as well as with the monomorphic "subtaxon" recoding method of Nixon and Davis (1991). Both approaches yield highly compatible results, and we here discuss a new classification of the Gentianales based on (i) monophyletic groups identified by outgroup analysis, and (ii) the maximal portrayal of evidence provided by subtaxon polymorphism recoding. Most prominently, the Loganiaceae sensu lato are divided into four segregate families, two previously named (Loganiaceae sensu stricto and Strychnaceae), and two defined as a result of this study (Gelsemiaceae, L. Struwe & V. A. Albert, stat. nov. and Geniostomaceae, L. Struwe & V. A. Albert, fam. nov.). Apocynaceae (incl. Asclepiadaceae), Gentianaceae (incl. Loganiaceae—Potalieae), and Rubiaceae remain as monophyletic families. Outgroup analysis supports both the monophyly of the Gentianales as well as the exclusion from the order of Buddleja, Desfontainia, Plocosperma, Polypremum , and Retzia (all Loganiaceae sensu Leeuwenberg and Leenhouts).     

Phylogenetic affiliations of members of the heterogeneous lichen-forming fungi of the genus Lecidea sensu Zahlbruckner (Lecanoromycetes, Ascomycota)

The genus Lecidea Ach. sensu lato (sensu Zahlbruckner) includes almost 1200 species, out of which only 100 species represent Lecidea sensu stricto (sensu Hertel). The systematic position of the remaining species is mostly unsettled but anticipated to represent several unrelated lineages within Lecanoromycetes. This study attempts to elucidate the phylogenetic placement of members of this heterogeneous group of lichen-forming fungi and to improve the classification and phylogeny of Lecanoromycetes. Twenty-five taxa of Lecidea sensu lato and 22 putatively allied species were studied in a broad selection of 268 taxa, representing 48 families of Lecanoromycetes. Six loci, including four ribosomal and two protein-coding genes for 315- and 209-OTU datasets were subjected to maximum likelihood and Bayesian analyses. The resulting well supported phylogenetic relationships within Lecanoromycetes are in agreement with published phylogenies, but the addition of new taxa revealed putative rearrangements of several families (e.g. Catillariaceae, Lecanoraceae, Lecideaceae, Megalariaceae, Pilocarpaceae and Ramalinaceae). As expected, species of Lecidea sensu lato and putatively related taxa are scattered within Lecanoromycetidae and beyond, with several species nested in Lecanoraceae and Pilocarpaceae and others placed outside currently recognized families in Lecanorales and orders in Lecanoromycetidae. The phylogenetic affiliations of Schaereria and Strangospora are outside Lecanoromycetidae, probably with Ostropomycetidae. All species referred to as Lecidea sensu stricto based on morphology (including the type species, Lecidea fuscoatra [L.] Ach.) form, with Porpidia species, a monophyletic group with high posterior probability outside Lecanorales, Peltigerales and Teloschistales, in Lecanoromycetidae, supporting the recognition of order Lecideales Vain. in this subclass. The genus name Lecidea must be redefined to apply only to Lecidea sensu stricto and to include at least some members of the genus Porpidia. Based on morphological and chemical similarities, as well as the phylogenetic relationship of Lecidea pullata sister to Frutidella caesioatra, the new combination Frutidella pullata is proposed here.     

The Molecular Identification and Antifungal Susceptibilities of Aspergillus Species Causing Otomycosis in Tochigi,Japan

Aspergillus species are the most common pathogenic fungi involved in otomycosis, an infection of the outer ear canal. In this study, we examined the incidence of Aspergillus infections and the antifungal susceptibilities of 30 Aspergillus species isolates from patients with otomycosis who visited Saiseikai Utsunomiya Hospital between August 2013 and July 2016. Based on the morphological test results, the strains were identified as Aspergillus niger sensu lato (20 strains), A. terreus sensu lato (7 strains), and A. fumigatus sensu lato (3 strains). In contrast, the molecular identifications based on analyzing the isolates’ partial β-tubulin gene sequences revealed them to be A. niger sensu stricto (12 strains), A. tubingensis (8 strains), A. terreus sensu stricto (7 strains), and A. fumigatus sensu stricto (3 strains). The antifungal susceptibility test results indicated that strains of A. tubingensis and A. niger sensu stricto displayed lower susceptibilities to ravuconazole, compared with the other isolates. The Aspergillus strains from this study showed low minimum inhibitory concentrations toward the azole-based drugs efinaconazole, lanoconazole, and luliconazole. Therefore, these topical therapeutic agents may be effective for the treatment of otomycosis.

     

Identification of a New Borrelia Species among Small Mammals in Areas of Northern Spain Where Lyme Disease Is Endemic

The role of small mammals as reservoir hosts for Borrelia burgdorferi was investigated in several areas where Lyme disease is endemic in northern Spain. A low rate of infestation by Ixodes ricinus nymphs was found in the small mammal populations studied that correlated with the near-absence of B. burgdorferi sensu lato in 184 animals tested and with the lack of transmission of B. burgdorferi sensu lato to I. ricinus larvae that fed on them. In contrast, questing ticks collected at the same time and in the same areas were found to carry a highly variable B. burgdorferi sensu lato repertoire (B. burgdorferi sensu stricto, Borrelia garinii, Borrelia valaisiana, and Borrelia afzelii). Interestingly, the only isolate obtained from small mammals (R57, isolated from a bank vole) grouped by phylogenetic analyses with other Borrelia species but in a separate clade from the Lyme disease and relapsing fever organisms, suggesting that it is a new species. This new agent was widely distributed among small mammals, with infection rates of 8.5 to 12% by PCR. Moreover, a high seroprevalence to B. burgdorferi sensu lato was found in the animal sera, suggesting cross-reactivity between B. burgdorferi sensu lato and R57. Although small mammals do not seem to play an important role as reservoirs for B. burgdorferi sensu lato in the study area, they seem to be implicated in the maintenance of spirochetes similar to R57.     

Substantial Rise in the Prevalence of Lyme Borreliosis Spirochetes in a Region of Western Germany over a 10-Year Period

More than a decade after a study on the transmission cycle of Borrelia burgdorferi sensu lato in the Siebengebirge, a nature reserve near Bonn, Germany, questing nymphal and adult Ixodes ricinus ticks were collected again in three selected areas of the same low mountain range and examined for infection with B. burgdorferi sensu lato. Between May and October 2001, a total of 1,754 ticks were collected by blanket dragging; 374 ticks were analyzed for B. burgdorferi sensu lato by both an immunofluorescence assay (IFA) and at least two different PCR tests, whereas 171 ticks were analyzed by PCR only. By combining all assays, an average of 14% of the ticks tested positive for B. burgdorferi sensu lato, 5.5, 15.8, and 21.8% in the three collection areas. Of the nymphs and adults examined, 12.9 and 21.1%, respectively, were found to be spirochete infected. A lower total infection prevalence was obtained by IFA (14.4%) than by a nested PCR approach (16.5%), but both were higher than that obtained by a simple PCR approach (11.9%). Compared with data collected over a decade ago, the mean infection prevalence of B. burgdorferi sensu lato in the ticks was significantly higher for all three biotopes, whereas a similar pattern of habitat-specific infection prevalence was observed. Genotyping of B. burgdorferi sensu lato revealed high relative prevalences of B. valaisiana (identified in 43.1% of infected ticks) and B. garinii (32.3%), whereas B. afzelii (12.3%) and B. burgdorferi sensu stricto (1.5%) were relatively rare. We conclude that B. burgdorferi sensu lato infection has increased in this region over the last 15 years due to presently unknown changes in ecological conditions, perhaps related to climate change or wildlife management.     

Local variations in the distribution and prevalence of Borrelia burgdorferi sensu lato genomospecies in Ixodes ricinus ticks.

Unfed nymphal and adult Ixodes ricinus ticks were collected from five locations within the 10,000-ha Killarney National Park, Ireland. The distribution and prevalence of the genomospecies of Borrelia burgdorferi sensu lato in the ticks were investigated by PCR amplification of the intergenic spacer region between the 5S and 23S rRNA genes and by reverse line blotting with genomospecies-specific oligonucleotide probes. The prevalence of ticks infected with B. burgdorferi sensu lato was significantly variable between the five locations, ranging from 11.5 to 28.9%. Four genomospecies were identified as B. burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, and VS116. Additionally, untypeable B. burgdorferi sensu lato genomospecies were identified in two nymphs. VS116 was the most prevalent of the genomospecies and was identified in 50% of the infected ticks. Prevalences of B. garinii and B. burgdorferi sensu stricto were similar (17 and 18%, respectively); however, significant differences were observed in the prevalence of these genomospecies in mixed infections (58.8 and 23.5%, respectively). Notably, the prevalence of B. afzelii was low, comprising 9.6 and 7.4%, respectively, of single and mixed infections. Significant variability was observed in the distribution and prevalence of B. burgdorferi sensu lato genomospecies between locations in the park, and the diversity and prevalence of B. burgdorferi sensu lato genomospecies was typically associated with woodland. The distributions of B. burgdorferi sensu lato genomospecies were similar in wooded areas and in areas bordering woodland, although the prevalence of B. burgdorferi sensu lato infection was typically reduced. Spatial distributions vegetation composition, and host cenosis of the habitats were identified as factors which may affect the distribution and prevalence of B. burgdorferi sensu lato genomospecies within the park.     

Evaluation of real-time PCR targeting hbb gene for Borrelia species identification

Several molecular methods have been employed for Borrelia species identification. Newly developed technology, real-time polymerase chain reaction (RT-PCR), combines simultaneous amplification, detection and differentiation of strains in one PCR run. The aim of the study was to perform and evaluate RT-PCR for Borreliaburgdorferi sensu lato species identification. Borrelia species identification was accomplished on 374 Borrelia strains using two approaches: 1.) MluI restriction of entire borrelial chromosome (MluI-large restriction fragment patterns, LRFP), and 2.) RT-PCR targeting hbb gene and specific melting temperature (Tm) detection. The results of the two molecular methods were compared. With MluI-RFLP we were able to differentiate all Borrelia species and their subtypes within particular species. RT-PCR based on Tm determination identified unique strains within the species Borreliaafzelii (Tm 66.11 °C), B. burgdorferi sensu stricto (Tm 68.18 °C), Borreliaspielmanii (Tm 59.45 °C) and Borreliavalaisiana (Tm 59.62 °C). We were not able to distinguish the last two species that shared almost identical Tm. The large majority of Borreliagarinii strains shared Tm 51.42 °C, while subtype Mlg4 was characterized by Tm 56.87 °C. Strains of Borrelialusitaniae species also were heterogeneous; human isolate had Tm 63.47 °C while two tick isolates shared Tm 61.77 °C. Differences inside hbb gene enabled differentiation of the majority of Borrelia species, and revealed two clusters within B. garinii and B. lusitaniae species, respectively, but it was not possible to distinguish B. spielmanii form B. valaisiana. The major advantage of RT-PCR was that it was easy to perform and that the results were obtained within a few hours.     

Molecular Identification and Analysis of Borrelia burgdorferi Sensu Lato in Lizards in the Southeastern United States

Lyme borreliosis (LB) group spirochetes, collectively known as Borrelia burgdorferi sensu lato, are distributed worldwide. Wild rodents are acknowledged as the most important reservoir hosts. Ixodes scapularis is the primary vector of B. burgdorferi sensu lato in the eastern United States, and in the southeastern United States, the larvae and nymphs mostly parasitize certain species of lizards. The primary aim of the present study was to determine whether wild lizards in the southeastern United States are naturally infected with Lyme borreliae. Blood samples obtained from lizards in Florida and South Carolina were tested for the presence of LB spirochetes primarily by using B. burgdorferi sensu lato-specific PCR assays that amplify portions of the flagellin (flaB), outer surface protein A (ospA), and 66-kDa protein (p66) genes. Attempts to isolate spirochetes from a small number of PCR-positive lizards failed. However, PCR amplification and sequence analysis of partial flaB, ospA, and p66 gene fragments confirmed numerous strains of B. burgdorferi sensu lato, including Borrelia andersonii, Borrelia bissettii, and B. burgdorferi sensu stricto, in blood from lizards from both states. B. burgdorferi sensu lato DNA was identified in 86 of 160 (54%) lizards representing nine species and six genera. The high infection prevalence and broad distribution of infection among different lizard species at different sites and at different times of the year suggest that LB spirochetes are established in lizards in the southeastern United States.     

Enzyme activities ofBorrelia burgdorferi sensu lato

Activities of 19 enzymes were tested by the API ZYM system in 13 strains ofBorrelia burgdorferi sensu lato (B. burgdorferi sensu stricto,B. afzelii, B. garinii, B. lusitaniae, B. valaisiana) grown in liquid BSK-H medium supplemented with rabbit serum. All strains produced acid phosphatase, esterase (C4), esterase-lipase (C8), leucine arylamidase and naphthol-AS-BI-phosphohydrolase. Nine strains also produced alkaline phosphatase, and three strains produced α-glucosidase. The API ZYM system probably cannot be used for differentiation betweenB. burgdorferi sensu lato genomospecies.     

Towards a revision of the genus Parastenocaris Kessler, 1913: establishment of Simplicaris gen. nov. from groundwaters in central Italy and review of the P. brevipes-group (Copepoda, Harpacticoida, Parastenocarididae)

A new genus Simplicaris (Copepoda, Harpacticoida, Parastenocarididae) is established to accommodate two species collected from deep groundwater in Italy, S. lethaea sp. nov. and S. veneris (Cottarelli & Maiolini, 1980) comb. nov. Parastenocaris hippuris Hertzog, 1938 and P. aedes Hertzog, 1938 are ranked as incertae sedis within the genus. Members display complete absence of leg 5 in both sexes and an unusual elongation of the first exopodal segments of legs 1–4, in which exp-1 is distinctly longer than exp-2 or -3, or as long as exp-2 and -3 combined. As the systematic status of the family Parastenocarididae and of the type genus Parastenocaris is still in flux, a list of phylogenetically informative characters is proposed, along with a discussion of their various states in representative members of the family. The genus Parastenocaris sensu stricto is redefined to comprise only the brevipes -group. The remaining members of the genus are considered Parastenocaris sensu lato pending a thorough revision of the family.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 417−436.