New mayfly nymphs (Insecta: Ephemeroptera) from Yixian Formation,China

Three new species of mayfly nymphs, Clavineta excavata sp. nov., Clavineta brevinodia sp. nov., and Siberiogenites branchicillus sp. nov., from the Yixian Formation (Late Jurassic-Early Cretaceous) in western Liaoning Province, China, are described. These mature nymphs are small-sized, with the body less than 16.0 mm long. The systematic position of the genera Clavineta and Siberiogenites, which are recorded for the first time in the Yixian Formation, is briefly discussed.     

Taxonomy of the fossil grylloblattid nymphs (Insecta: Grylloblattida)

Nymphs of fossil grylloblattid insects are revised. Newly described taxa are Lemmatonympha gracilissima gen. et sp. nov. and Kaltanympha vorcutensis sp. nov. from the Verkhne-Syr’yaginsk locality (Ufimian, Lek-Vorkuta Formation in the Vorkuta Coal Basin), genera Sylvalitoralis gen. nov. and Tshebardanympha gen. nov. from the Tshekarda locality (Kungurian, Koshelevka Formation, Middle Urals), Tataronymphakamensis gen. et sp. nov. from the Tikhie Gory locality (Lower Kazanian, linguloid beds of the Baitugan Formation, Tatarstan), and Kaltanympha ornata sp. nov. from the Kerbo locality (Upper Tatarian, lower part of the Degali Formation, Evenki Autonomous Region). Liomopterites (?) gracilis Sharov, 1961 from Lower Kazanian deposits of the Kuznetsk Formation in the Kuznetsk Basin is transferred to the genus Kaltanympha Sharov, 1961; Permonympha arcuata Sharov, 1957 from the same locality is synonymized under Permonympha gracile Sharov, 1957; the nymph described from the Karatau locality (Upper Jurassic, Karabastau Formation in southern Kazakhstan) as Blattogryllus karatavicus Rasnitsyn, 1976 is excluded from grylloblattids. Keys to extinct grylloblattid nymphs are provided.     

First description of axymyiid fossils (Insecta: Diptera: Axymyiidae)

Two species of fossil insects from the Daohugou Formation of Chifeng City in Nei Monggol Autonomous Region, northeastern China are described, and recognized as Psocites pectinatus (Hong, 1983) nov. emend., nov. transl. and P. fossilis nov. sp. They are the oldest representatives of the family Callovian or Axymyiidae, and first described of this family in the Mesozoic. Although early the age of the fly-bearing beds is controversial, it is probably Oxfordian or Kimmeridgian (Late Jurassic) rather than Early Cretaceous or Middle Jurassic.     

Late Jurassic cockroaches (Insecta,Blattaria) from the Houtiyn-Hotgor locality in Mongolia

A low-diversity cockroach assemblage from the Upper Jurassic of the Houtiyn-Hotgor locality in Mongolia is described, comprising Solemnia alexandri gen. et sp. nov. (Caloblattinidae), Blattula choutinensis sp. nov. (Blattulidae) and a presumed Triassic relict Irreblatta relicta gen. et sp. nov. (incertae familiae). The carnivorous Raphidiomimidae supposedly originated directly from the Caloblattinidae.     

The daily activity patterns of mayfly nymphs (Ephemeroptera)

Nymphs of Baëtis rhodani (Pictet), Ephemerella ignita (Poda), Ecdyonurus venosus (Fabricius), Rhithrogena semicolorata (Curtis), and Heptagenia lateralis (Curtis) showed a similar endogenous rhythm of activity under conditions of natural illumination, continuous light and continuous darkness; and were most active at night when they moved from the lower to the upper surface of the stone. The nymphs were positively thigmotactic and negatively phototactic in flowing water, but these taxes and the endogenous activity rhythm of all species except Heptagenia lateralis changed markedly when the flow of water ceased.     

The effects of extended photoperiods on the drift of the mayfly ephemerella subvaria McDunnough (Ephemeroptera : Ephemerellidae)

Field drift studies indicated that the nocturnal drift density of E. subvaria nymphs was greater in early May than in early November.Laboratory studies showed that the number of individuals appearing in the drift was a linear function of the duration of the preceding photoperiod. Nymphs had a greater propensity to drift when they were not in a state of active growth than when they were growing. The tendency of individuals in a single laboratory population to drift was observed to change under conditions of constant temperature and randomized photoperiod. This suggests that the shift was due to some internal physiological change rather than to an external cue.It is suggested that drift in E. subvaria functions as a method relocation from fast-water areas to slow-water pools and stream margins. Redistribution to these areas may reduce mortality incurred during spring run-off and during emergence.     

New and little-known grylloblattids of the family Geinitziidae (Insecta: Grylloblattida) from the Triassic and Jurassic of Europe,Asia, and South Africa

The fossil history of the family Geinitziidae is reviewed. New taxa are described in the family: Shurabia hissarica, sp. nov. (Lower Jurassic of Tajikistan), Sh. shartegica, sp. nov. (Upper Jurassic of Mongolia), Sh. serrata, sp. nov. and Ginitzia sagulensis, sp. nov. (both Lower Jurassic of Kyrgyzstan). The subfamily Stegopterinae Sharov, 1961 is synonymized under Geinitziinae Handlirsch, 1906. The genera Minesedes Fujiyama, 1973 and Ominea Fujiyama, 1973 (Upper Triassic of Japan) are synonymized under Shurabia Martynov, 1937 and Geinitzia Handlirsch, 1906, respectively. Geinitzia varia Bode, 1953 (Lower Jurassic of Germany) and Fletchizia picturata Riek, 1976 (Upper Triassic of South Africa) are redescribed from their holotypes. F. kapokraalensis Wappler, 2001 and F. aleda Wappler, 2001 (both Upper Triassic of South Africa) are transferred to the genus Shurabia.     

Notobaetis: A New Genus of Baetidae (Ephemeroptera) from South America

A new genus and species, Notobaetis penai, n. gen., n. sp., of Baetidae (Ephemeroptera), is described based upon reared specimens collected from the Cordoba Province of Argentina. This new genus appears to be phenetically intermediate between Baetis Leach and Centroptilum Eaton while possessing a unique combination of characters and one autapomorphic character.     

Biometric studies of some stoneflies and a mayfly (Plecoptera and Ephemeroptera)

Aspects of the nymphal/adult developmental change were investigated in biometric studies of several species of Plecoptera: Nemouridae near Schlitz, Hesse, Germany. Preliminary information on the mayfly, Baetis vernus Curtis, is also provided. Nemourid nymphs pass through 3 wing bearing stages before reaching adulthood. Instars can be identified by their characteristic shapes, as expressed by the wing length/head width (WL/HW) ratio. Size does not allow instar discrimination, mainly due to sexual size differences. HW is ca 10% larger in last instar female than in male nemourid nymphs; exuviae shed at the moult to adult represent about 14% of nymphal ash free dry weight (AFDW). Biomass lost with exuviae during the many larval moults should be accounted for in estimates of production. Freshly emerged nemourid females are about 6% larger and 30% heavier than males. The HW/AFDW relationship is the same in both sexes. Through terrestrial feeding during adult life, males double their weight on average. Mature females are up to three times heavier than freshly emerged ones. They invest about 30% of their final AFDW in reproduction.Shape of last instar nymphal Baetis was expressed as the ratio wing length/mesonotum length. It is size-dependent, a characteristic, instar-specific shape may not occur in this mayfly. Nymphal and subimaginal exuviae together represent about 14% of last instar nymphal dry weight. Females of Baetis are about 55% heavier than males. Unlike in Plecoptera, the size/weight (ML/AFDW) relationship differs between sexes.     

Global diversity of mayflies (Ephemeroptera, Insecta) in freshwater

The extant global Ephemeroptera fauna is represented by over 3,000 described species in 42 families and more than 400 genera. The highest generic diversity occurs in the Neotropics, with a correspondingly high species diversity, while the Palaearctic has the lowest generic diversity, but a high species diversity. Such distribution patterns may relate to how long evolutionary processes have been carrying on in isolation in a bioregion. Over an extended period, there may be extinction of species, but evolution of more genera. Dramatic extinction events such as the K-T mass extinction have affected current mayfly diversity and distribution. Climatic history plays an important role in the rate of speciation in an area, with regions which have been climatically stable over long periods having fewer species per genus, when compared to regions subjected to climatic stresses, such as glaciation. A total of 13 families are endemic to specific bioregions, with eight among them being monospecific. Most of these have restricted distributions which may be the result of them being the relict of a previously more diverse, but presently almost completely extinct family, or may be the consequence of vicariance events, resulting from evolution due to long-term isolation. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

New hymenopteran insects (Insecta: Vespida) from the lower or middle Jurassic of India

Hymenopterans Xyelula alexandri Rasnitsyn, sp. nov. (Sepulcidae) and Kotaphialtites frankmortoni Rasnitsyn, gen. et sp. nov. (Ephialtitidae) are described from the Lower or Middle Jurassic Kota Formation, Andhra Pradesh, India. These finds prove a considerable similarity between the Gondwanan and Laurasian hymenopteran faunas during the Jurassic, as well as during the Triassic and Cretaceous.     

Phylogeny of the mayfly family Leptohyphidae (Insecta: Ephemeroptera) in South America

Abstract.  A cladistic analysis of the South American members of the Ephemeropteran family Leptohyphidae is presented. A matrix of 73 taxa and 124 morphological characters was analysed under two distinct weighting criteria (implied weighting, which weights characters as a whole, and self-weighted optimization, which differentially weights character state transformations). To assess the monophyly of the Leptohyphidae, representatives of Ephemerellidae, Ephemerythidae, Machadorythidae, Teloganodidae, Tricorythidae, Coryphoridae and Melanemerellidae were also included. Trees were rooted in Ephemerellidae. Conspicuous differences in consensus topology occur when transformation costs among character states are weighted (including asymmetries). The differences in the assessments of character reliability in the two weighting criteria used are discussed. In many cases, self-weighting, in allowing for asymmetries in transformation costs, considered many of the character state transformations as more reliable (= informative) than implied weights (which needlessly down-weighted the whole character). The results confirm the monophyly of Leptohyphidae and support its sister-group relationship with Coryphoridae. The shortest trees do not support the recently proposed division of Leptohyphidae into two subfamilies. Ephemerelloidea higher classification is discussed briefly.     

Revision and description of water boatmen from the Middle-Upper Jurassic of Northern and Northeastern China (Insecta: Hemiptera: Heteroptera: Corixidae)

Four adult and immature water boatmen from the Middle Jurassic and uppermost Middle Jurassic or lowermost Upper Jurassic Jiulongshan, Haifanggou and Daohugou formations in the northern and northeastern China are described as Yanliaocorixa chinensis (Lin, 1976), Jiulongshanocorixa genuina gen. et sp. nov., and Daohugocorixa vulcanica gen. et sp. nov., referred to the extinct subfamily Velocorixinae, and Karataviella popovi sp. nov., referred to the extant subfamily Diaprepocorinae. All the forms have previously been identified as one species, Yanliaocorixa chinensis. This species, found only in the Haifanggou Formation, is absent from the Jiulongshan Formation and other sites in China. The systematic position of corixids recorded earlier from the Mesozoic of China is reviewed and reassessed. Assemblages of dominant aquatic insects from various Jurassic nonmarine sedimentary basins in northern and northeastern China are described for the first time. They are entirely different between the Jiulongshan, Haifanggou, and Daohugou formations. The first formation is probably older than the other two.     

Tettigarctidae (Insecta: Hemiptera: Cicadoidea) from the Middle Jurassic of Inner Mongolia, China

Three new species of Tettigarctidae from the Middle Jurassic of Daohugou, China are described: Shuraboprosbole daohugouensis nov. sp., S. minuta nov. sp., and S. media nov. sp. The revised diagnostic characters of Shuraboprosbole Becker-Migdisova are provided based on well-preserved whole-bodied fossil tettigarctids. So far, only four definitive species of Tettigarctidae are recorded from the Mesozoic of China. The pronotum concealing major of mesonotum seems to be an autapomorphy of Tettigarctinae. The “cicadellid-like tarsi” found in Cicadellidae and Brazilian Tettigarctidae are probably a parallel evolution.     

Structure and spatial variability of mayfly (Ephemeroptera) communities in the upper Hron River basin

Mayflies were sampled from eleven sites in six tributaries of the upper Hron River. Mayfly communities were ordinated and related to environmental factors using multiple regression and principal component analysis. Communities of headwater sites were dominated by Rhithrogena iridina which was gradually replaced by Baetis alpinus, at the lower reaches. Total mayfly species richness was inversely related to stream slope and overall abundance was inversely related to altitude. The prominent factor influencing mayfly communities was a complex longitudinal gradient as proposed by the river continuum concept. There were no significant differences in community composition and structure between the left-and right-hand tributaries of the Hron River.     

The first agetopanorpine mecopteroid insect from Middle Permian of China (Insecta: Mecoptera: Permochoristidae)

Sinoagetopanorpa permiana n. gen., n. sp., first Chinese Permian Agetopanorpinae, is described and compared to the other genera of this group.     

Discovery of an alien species of mayfly in South America (Ephemeroptera)

Despite its wide, almost worldwide distribution, the mayfly genus Cloeon Leach, 1815 (Ephemeroptera: Baetidae) is restricted in the Western hemisphere to North America, where a single species is reported. In the Neotropics, except for some species wrongly attributed to the genus in the past, there are no records of Cloeon. Recently, however, specimens of true Cloeon were collected along the coast of Espírito Santo, Southeastern Brazil. In order to verify the hypothesis that this species was recently introduced to Brazil, our aim was to identify the species based on morphological and molecular characters and to confirm the presence of true representatives of the genus in the Neotropics. Our results revealed that the specimens found in Brazil belong to the Afrotropical species C. smaeleni Lestage, 1924. The identity of the species, its distribution, along with its previous absence in regularly sampled sites, is a clear sign that the specimens of C. smaeleni found in Espírito Santo are introduced, well established, and that the colonization took place very recently.     

The first find of chrysomelids (Insecta: Coleopetra: Chrysomeloidea) from Callovian-Oxfordian Daohugou biota of China

Tarsomegamerus mesozoicus nov. gen., nov. sp., an almost complete specimen of leaf beetle from the Callovian-Oxfordian of Daohugou Formation in Inner Mongolia, China is described. Tarsomegamerus mesozoicus is assigned to the Protoscelinae (Chrysomelidae, Coleoptera). This new leaf beetle represents the first record of chrysomeloids from Mesozoic of China and it extends the geographical distribution of Protoscelinae from central Asia into eastern Asia. This find provides new fossil material for studying the origin and evolution of Chrysomeloidea and by making a stratigraphic correlation of the correlative non-marine sedimentary rocks. Although the age of the Daohugou Formation is debatable it is most likely Callovian-Oxfordian (latest Middle Jurassic-earliest Late Jurassic) rather than early Middle Jurassic (late Aalenian-early Bajocian) or Early Cretaceous.