Relict populations of Diaphanosoma (Cladocera: Ctenopoda) in the Chadian Sahara, with the description of a new species

We record two species of Diaphanosoma from Ounianga and Tibesti in Northern Chad, the first ctenopods to be found in the Sahara desert. One species, from a freshwater guelta on the south flanks of the Tibesti (D. excisum) is tropical; the second species, found in a freshwater lake in a largely saline environment (the Ounianga plateau) is new to science (D. bopingi sp.nov.) and is here described, with special attention to some previously unnoticed structures on the postabdomen. Its relatives are northern species that may transgress into the tropics but largely live outside of them. They are also more salt-tolerant than the tropical D. excisum. The latter is considered a relict of Megachad times, while the new species is considered a relict of more humid but also cooler times in the desert. 

Micromoina arboricola n. gen., n. spec. (Crustacea: Cladocera), a new moinid living in a forest tree-hole in Minas Gerais, Brazil

With a maximum size of ca 0.5 mm, Micromoina arboricola is among the smallest moinids known to date. It was discovered in a flooded treehole in a forest in the Medio Rio Doce Valley, Minas Gerais, Brazil, where it mainly feeds on particulate organic matter derived from the vinhatico tree . However, it is easily cultured in the lab on a diet of green algae plus yeast and pelleted fish food. Structurally, it is a miniature version of a moinid, distinguished by characters on the antennules (both sexes) and the postabdomen. The latter is peculiar in shape, in lacking a basal spine, and in having only three lateral plumose setae. A comparative investigation of the barcoding fragment of the COI gene in a number of moinids confirms the family Moinidae as composed of several genera, as well as the status of the new taxon.

Dynamics in space and time of four testate amoebae (Difflugia spp.) co-existing in the zooplankton of a reservoir in southern China

We studied a long time series of the dynamics in space and time of four species of Difflugia (thecamoebae) that co-exist in the pelagic plankton of Liuxihe Reservoir, an oligo-mesotrophic impoundment in southern China, during 8-9 months ("summer" form March to November), and retreat to the benthos during the rest of the year ("winter"). We discuss the reasons for the winter retreat, and suggest that predator evasion may be involved, although temperature-linked physiological effects (like the rate of gas bubble production) appear more probable. Clear diel vertical migration of Difflugia was not observed, but patchiness was common. We found no evident lake edge-effects in the spatial pattern either, but the abundances were strongly influenced by trophic conditions and increased by up to one order of magnitude in the upstream, eutrophic sections of the reservoir.

Cladocera of the Lençóis Maranhenses (NE - Brazil): faunal composition and a reappraisal of Sars' Method

We studied the Cladocera of a group of ephemeral interdunal pools in the Lençóis Maranhenses, Maranhão State (NE - Brazil) and recorded 34 species. The fauna was overwhelmingly neotropical, with no evidence of invasive species. Species composition differed in Lagoa da Colher, an acid system. We provide notes on behaviour, morphology and taxonomy of some lesser-known anomopods, with emphasis on the Chydoridae. We figure male Oxyurella longicaudis, Chydorus eurynotus, Disparalona leptorhyncha, Alonella dadayi and A. clathratula. We provide notes on the "Sars' Method", hatching of freshwater crustaceans from dry mud, a simple technique that complements the information of hit-and-run surveys. About half of the total species number (44%) was revived through this method; 18% of species were additional to field-collected samples. The Sars' method also yielded abundant specimens of rare species, useful for identification and studies on behaviour.

Lake Borullus of the Nile Delta: a short history and an uncertain future

Borullus, the most centrally situated of the Nile Delta lakes, probably evolved around the eighth century AD from a preexisting salt marsh by fluviatile deposition of sand dunes north of the lake and subsidence of the preexisting tidal swamp behind this barrier. It was flooded yearly (September-December) by the Sebennytic branch of the Nile, and evacuated water through an exit, Bughaz. At low river levels, this process reversed and Bughaz functioned as a marine inlet. Because of this switch, its fauna and flora contained a mix of marine, freshwater, and brackish-water species. Around the mid-nineteenth century, damming of the Nile began, culminating with the high Aswan Dam (1964) that brought the yearly flood fully under control. As a result, a steady flow of Nile water, used for irrigated delta agriculture, began to drain to the lake and became a constant evacuator to the Mediterranean. It turned almost fresh, and its fishery, formerly marine and mullet-based, became cichlid-catfish based. However, rice and other new delta crops caused huge amounts of nutrients to wash down the drains, and currently the lake is eutrophied and only resists hypertrophication because of the low residence time of its water. Finally, the damming of the Nile terminated the influx to the delta of a yearly sediment layer, but subsidence and coastal erosion continue and are now consuming the sand bar that separates the lake from the sea.

Phylogenetic relationships, divergence time estimation, and global biogeographic patterns of calopterygoid damselflies (odonata, zygoptera) inferred from ribosomal DNA sequences

The calopterygoid superfamily (Calopterygidae + Hetaerinidae) is composed of more than twenty genera in two families: the Calopterygidae (at least 17) and the Hetaerinidae (at least 4). Here, 62 calopterygoid (ingroup) taxa representing 18 genera and 15 outgroup taxa are subjected to phylogenetic analysis using the ribosomal 18S and 5.8S genes and internal transcribed spacers (ITS1, ITS2). The five other families of calopterid affinity (Polythoridae, Dicteriadidae, Amphipterygidae, Euphaeidae, and Chlorocyphidae) are included in the outgroup. For phylogenetic inference, we applied maximum parsimony, maximum likelihood, and the Bayesian inference methods. A molecular phylogeny combined with a geographic analysis produced a well-supported phylogenetic hypothesis that partly confirms the traditional taxonomy and describes distributional patterns. A monophyletic origin of the calopterygoids emerges, revealing the Hetaerinid clade as sister group to the Calopterygidae sensu strictu. Within Calopterygidae, seven clades of subfamily rank are recognized. Phylogenetic dating was performed with semiparametric rate smoothing by penalized likelihood, using seven reference fossils for calibration. Divergence time based on the ribosomal genes and spacers and fossil constraints indicate that Calopteryginae (10 genera, approximately 50% of all Calopterygid taxa studied here), Vestalinae (1 genus), and Hetaerinidae (1 genus out of 4 studied here) started radiating around 65 Mya (K/T boundary). The South American Iridictyon (without distinctive morphology except for wing venation) and Southeast Asian Noguchiphaea (with distinctive morphology) are older (about 86 My) and may be survivors of old clades with a Gondwanian range that went extinct at the K/T boundary. The same reasoning (and an even older age, ca. 150 My) applies to the amphipterygids Rimanella and Pentaphlebia (South America-Africa). The extant Calopterygidae show particular species and genus richness between west China and Japan, with genera originating between the early Oligocene and Pleistocene. Much of that richness probably extended much wider in preglacial times. The Holarctic Calopteryx, of Miocene age, was deeply affected by the climatic cooling of the Pliocene and by the Pleistocene glaciations. Its North American and Japanese representatives are of Miocene and Pliocene age, respectively, but its impoverished Euro-Siberian taxa are late Pliocene-Pleistocene, showing reinvasion, speciation, and introgression events. The five other calopterid families combine with the Calopterygidae and Hetaerinidae to form the monophyletic cohort Caloptera, with Polythoridae, Dicteriadidae, and Amphipterygidae sister group to Calopterygoidea. The crown node age of the latter three families has an age of about 157 My, but the Dicteriadidae and Polythoridae themselves are of Eocene age, and the same is true for the Euphaeidae and Chlorocyphidae. The cohort Caloptera itself, with about 197 My of age, goes back to the early Jurassic.

Phylogenetic analysis of anostracans (Branchiopoda: Anostraca) inferred from nuclear 18S ribosomal DNA (18S rDNA) sequences

The nuclear small subunit ribosomal DNA (18S rDNA) of 27 anostracans (Branchiopoda: Anostraca) belonging to 14 genera and eight out of nine traditionally recognized families has been sequenced and used for phylogenetic analysis. The 18S rDNA phylogeny shows that the anostracans are monophyletic. The taxa under examination form two clades of subordinal level and eight clades of family level. Two families the Polyartemiidae and Linderiellidae are suppressed and merged with the Chirocephalidae, of which together they form a subfamily. In contrast, the Parartemiinae are removed from the Branchipodidae, raised to family level (Parartemiidae) and cluster as a sister group to the Artemiidae in a clade defined here as the Artemiina (new suborder). A number of morphological traits support this new suborder. The Branchipodidae are separated into two families, the Branchipodidae and Tanymastigidae (new family). The relationship between Dendrocephalus and Thamnocephalus requires further study and needs the addition of Branchinella sequences to decide whether the Thamnocephalidae are monophyletic. Surprisingly, Polyartemiella hazeni and Polyartemia forcipata ("Family" Polyartemiidae), with 17 and 19 thoracic segments and pairs of trunk limb as opposed to all other anostracans with only 11 pairs, do not cluster but are separated by Linderiella santarosae ("Family" Linderiellidae), which has 11 pairs of trunk limbs. All appear to be part of the Chirocephalidae and share one morphological character: double pre-epipodites on at least part of their legs. That Linderiella is part of the Polyartemiinae suggests that multiplication of the number of limbs occurred once, but was lost again in Linderiella. Within Chirocephalidae, we found two further clades, the Eubranchipus-Pristicephalus clade and the Chirocephalus clade. Pristicephalus is reinstated as a genus.

Phylogenetic relationships inferred from ribosomal its sequences and biogeographic patterns in representatives of the genus Calopteryx (Insecta: Odonata) of the West Mediterranean and adjacent West European zone

Western Europe is a reinvasion zone for the riverine dragonfly genus Calopteryx (Insecta: Odonata). Reinvasion may have been from central West Asia or from the West Mediterranean refugium. Phylogenetic relationships of West Mediterranean and West European taxa of the genus Calopteryx from different localities were inferred from sequences of the internal transcribed spacers (ITS1 and ITS2) of the nuclear ribosomal RNA genes. Twenty-six taxa belonging to the species groups C. splendens, C. meridionalis, C. haemorrhoidalis, C. virgo, C. xanthostoma, and C. exul were analyzed, with two North American species, C. amata and C. aequabilis, as outgroup. Sequence data and phylogenetic analyses were used to infer biogeographical patterns. The ribosomal spacers (ITS1 and ITS2) and the intervening 5.8S rDNA gene were amplified by PCR and sequenced. The ITS2 sequences of the West Mediterranean and West European calopterygids show no length variation but the ITS1 region was slightly variable in length. The sequence variation for ITS1 and ITS2 regions between different West Mediterranean and West European calopterygids was 14.5 and 6.1%, respectively. Phylogenetic relationships inferred from ITS sequences only partly confirm morphological data. A monophyletic origin of all West Mediterranean and West European species emerged. They are separated into two main clades; the splendens-like forms and the virgo/meridionalis/haemorrhoidalis group. Intraspecific variability, indicating different stages of speciation, was detected only in West Mediterranean representatives (e.g., C. xanthostoma) but not in invasive representatives in West Europe. The North African endemic C. exul is more closely related to the Italian C. s. caprai than to C. splendens sensu strictu. Based on the present information, Cretan populations are the only splendens-like taxa in addition to C. s. caprai that deserve subspecies status.

Transmural myocardial infarction with coexisting critical aortic stenosis as an etiology for early myocardial rupture

Myocardial rupture is the most important cause of post-infarct sudden death after myocardial infarction other than shock and dysrhythmias. Usually unrecognized, pseudoaneurysm formation is a delayed consequence of myocardial rupture in a small portion of patients who will remain at high risk for late rupture and death. Clinical studies have defined a profile of the patient who is at increased risk for post-infarct myocardial rupture. We believe that an additional factor, ventricular outflow tract obstruction, may add to the risk of having a post infarct rupture. A high degree of suspicion by the clinician accompanied by the timely performance of diagnostic tests may help to decrease the mortality from this catastrophic event.

An examination of some Hexarthra species (Rotatoria) from western Canada and Nepal

Four species of Hexarthra are reported from ponds and lakes in western Canada. Two Rocky Mountain forms are described as new subspecies: Hexarthra bulgarica canadensis n.subsp., at high altitudes, and Hexarthra polyodonta jasperina n.subsp. The nominate subspecies of the latter is known only from saline Lake Van, Turkey. Hexarthra polyodonta jasperina occurs in low salinity lakes and differs morphologically from the nominate subspecies in having a moderately developed ventro-anterior lip. Hexarthra bulgarica bulgarica is a true high-mountain rotifer known from the Rila Mountains, Bulgaria (nominate subspecies), from the Himalayas (H. bulgarica nepalensis n.subsp.), and from the Rocky Mountains (H. bulgarica canadensis n.subsp.). The Nepalese subspecies differs from the nominate subspecies and from H. bulgarica canadensis in having a well developed ventro-anterior lip. Hexarthra bulgarica canadensis differs from the nominate subspecies in having more teeth on the unci, more spines on the ventral arm, and more filaments on all arms. The pair of spines on the dorsolateral arm is the main diagnostic character of the H. bulgarica group. Hexarthra mira (Hudson) occurred at intermediate and lower altitudes, and Hexarthra fennica (Levander) was identified from a saline lake in Saskatchewan where specimens were unusually large, but otherwise typical.