The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Rolf Georg Beutel - One of the best experts on this subject based on the ideXlab platform.
-
the evolution of Zoraptera
Systematic Entomology, 2020Co-Authors: Yoko Matsumura, Rolf Georg Beutel, Jose Albertino Rafael, Josenir Teixeira Câmara, Sheila Lima, Kazunori YoshizawaAbstract:Zoraptera is one of the most enigmatic and least understood orders in insects. Based on a wide taxon sampling from all continents where the group is known, we applied a phylogenetic approach using multiple DNA sequences to elucidate species‐level relationships. The resulting phylogeny shows that Zoraptera is divided into three major clades, and that two comprise species distributed on different continents. The monophyly of these clades is at least partly supported by shared derived morphological features. The divergence age estimation and ancestral distribution area reconstruction suggest an ancient origin and early radiation initiated in the Permian. Plate tectonics theory suggests that the present distribution of Zoraptera was mainly established by vicariance, rather than dispersal. The three major clades probably originated on the Pangaea supercontinent, or alternatively on the linked Gondwana and Laurasia supercontinents. Their ancient origin explains previously found conspicuous interspecific variation of the genital apparatus, sperm structure and mating behaviour, in striking contrast to a highly conserved general body morphology. We compiled data of available reproductive features and reconstructed the character evolution. Our analyses revealed repeated acquisitions and/or losses of a hyperelongated intromittent organ, mating hooks and tergal protuberances.
-
zorotypus pecten a new species of Zoraptera insecta from mid cretaceous burmese amber
Zootaxa, 2019Co-Authors: Yuta Mashimo, Patrick Muller, Rolf Georg BeutelAbstract:: A new species of the order Zoraptera, Zorotypus pecten sp. n., is described from mid-Cretaceous Burmese amber. It is tentatively assigned to the subgenus Octozoros based on 8-segmented antenna. A Gondwanan origin for Zoraptera is discussed based on the geographic distribution of extant and fossil Zorapterans.
-
the hairy beast zorotypus hirsutus sp n an unusual new species of Zoraptera insecta from burmese amber
Zootaxa, 2018Co-Authors: Yuta Mashimo, Patrick Muller, Hans Pohl, Rolf Georg BeutelAbstract:A new species of the order Zoraptera, Zorotypus hirsutus Mashimo sp. n., is described from mid-Cretaceous Burmese amber. The specimen is tentatively assigned to the subgenus Octozoros Engel based on number of antennomeres reduced from nine to eight. It is characterized by an unusually strong setation, appearing much more hirsute than other extant or extinct species of the order. Other unusual autapomorphic features are an elongated head capsule with a concave genal region and very slender, elongate antennomeres. The discovery of this aberrant species suggests that the morphological diversity of Zoraptera was much higher than previously expected. For a reliable placement of Zorotypus hirsutus the discovery of males and a robust species level phylogeny would be required.
-
a remarkable new species of Zoraptera zorotypus asymmetristernum sp n from kenya insecta Zoraptera zorotypidae
Zootaxa, 2018Co-Authors: Yuta Mashimo, Yoko Matsumura, Rolf Georg Beutel, Laban Njoroge, Ryuichiro MachidaAbstract:A new species of order Zoraptera, Zorotypus asymmetristernum Mashimo, n. sp., is described from Kakamega, Kenya, with its major diagnostic features and characteristics of the egg described and illustrated. The new species represents the sixth Zorapteran species from the Afrotropic ecozone. A brief discussion on vestigial eye spots of apteron individuals and a key to the species of the Afrotropic ecozone are provided.
-
the morphology and ultrastructure of salivary glands of Zoraptera insecta
Arthropod Structure & Development, 2017Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The salivary glands of two species of Zoraptera, Zorotypus caudelli and Zorotypus hubbardi, were examined and documented mainly using transmission electron microscopy (TEM). The results obtained for males and females of the two species are compared and functional aspects related to ultrastructural features are discussed. The salivary glands are divided into two regions: the secretory cell region and the long efferent duct, the latter with its distal end opening in the salivarium below the hypopharyngeal base. The secretory region consists of a complex of secretory cells provided with microvillated cavities connected by short ectodermal ducts to large ones, which are connected with the long efferent duct. The secretory cell cytoplasm contains a large system of rough endoplasmic reticulum and Golgi apparatus producing numerous dense secretions. The cells of the efferent duct, characterized by reduced cytoplasm and the presence of long membrane infoldings associated with mitochondria, are possibly involved in fluid uptaking from the duct lumen.
Michael S Engel - One of the best experts on this subject based on the ideXlab platform.
-
Evolution of the insects
2020Co-Authors: David A Grimaldi, Michael S EngelAbstract:Section 1. Diversity and Evolution: Introduction Species: their nature and number How many species of insects? Reconstructing evolutionary history Section 2. Fossil Insects: Insect fossilization Dating and ages Major fossil Insect deposits Section 3. Arthropods and the Origin of Insects: Onychophora: the velvet-worms Tardigrada: the water-bears Arthropoda: the jointed animals Hexapoda: the six-legged arthropods Section 4. The insects: Morphology of insects Relationships among the insect orders Section 5. Earliest insects: Archaeognatha: the bristletails Zygentoma: the silverfish +Rhyniognatha Section 6. Insects Take to the Skies: Pterygota, Wings, and flight Ephemeroptera: the mayflies +Palaeodictyopterida: extinct beaked insects Odonatoptera: dragonflies and early relatives Neoptera Section 7. The Polyneopterous Orders: Plecopterida Orthopterida Plecoptera: the stoneflies Embiodea: the webspinners Zoraptera: the Zorapterans Orthoptera: the grasshoppers, crickets, and kin Phasmatodea: the stick- and leaf insects +Titanoptera: the titanic crawlers +Caloneurodea: the Caloneurodeans Dermaptera: the earwigs Grylloblattodea: the ice crawlers Mantophasmatodea: the African rock crawlers Dictyoptera Blattodea: the roaches Citizen roach: the termites Mantodea: the mantises Section 8. The Paraneopteran Orders: Psocoptera: the 'bark'lice Phthiraptera: the true lice Fringe wings: Thysanoptera (thrips) The sucking bugs: Hemiptera Section 9. The Holometabola: problematic fossil orders The origins of complete metamorphosis On wings of lace: Neuropterida Section 10. Coleoptera: early fossils and overview of past diversity Archostemata Adephaga Myxophaga Polyphaga Strepsiptera: the enigmatic order Section 11. Hymenoptera: Ants, Bees, and Other Wasps: The Euhymenoptera and parasitism Aculeata Evolution of insect sociality Section 12. Antliophora: Scorpionflies, Flies, and Fleas: Mecopterida: mecopterans and relatives Siphonaptera: the fleas Evolution of ectoparasites and blood-feeders Diptera: the true flies Section 13. Amphiesmenoptera: The Caddisflies and Lepidoptera: Trichoptera: the caddisflies Lepidoptera: the moths and butterflies Section 14. Insects Become Modern: Cretaceous and Tertiary Periods: The Cretaceous flowering of the world: the Angiosperm Radiations Plant sex and insects: insect pollination Radiations of Phytophagous insects Austral arthropods: remnants of Gondwana? Insects, mass extinctions, and the K/T boundary The tertiary Mammalian radiations Pleistocene dispersal and species lifespans Island faunas Section 15. Epilogue: Why so many insect species? The future Glossary References Index.
-
Chapter 272 – Zoraptera
Encyclopedia of Insects, 2020Co-Authors: Michael S EngelAbstract:Publisher Summary This chapter focuses on the Zoraptera, smallest insect orders with only 35 living species and 10 more known from fossils. Zorapterans superficially resemble termites (Isoptera) and bark lice (Psocoptera) and they are classified near or within these groups. Individuals are typically less than 4 mm in body length excluding their antennae and live in small colonies. The most readily noticeable traits of the order are the expanded hind femora that bear stout spines on their ventral surface, the presence of only two tarsomeres (the basal most of which is greatly reduced in size), and paddle-shaped wings with reduced venation that are shed by an ill-defined basal fracture. Although Zorotypus species are gregarious and live in small colonies, they evidently do not distinguish between individuals from the same colony and introduced vagrants. Isolated individuals do not survive. Zorapterans spend much of their time grooming either themselves or other individuals. Zorapteran colonies at times can be found in wood or sawdust piles at lumber yards, owing to their relatively minute colony sizes, general scarcity, and apparent minimal ecological impact, it is unlikely that they will ever be considered of any economic importance.
-
zorotypus dilaticeps sp nov a remarkable Zorapteran Zoraptera in mid cretaceous burmese amber
Cretaceous Research, 2018Co-Authors: Diying Huang, Michael S EngelAbstract:Abstract A seventh species of fossil Zorapteran (Zoraptera) in mid-Cretaceous Burmese amber is described and figured from an apterous female (dealate). Zorotypus (s. str.) dilaticeps sp. nov. is exceptionally large in body size (ca. 3.9 mm), and can be readily distinguished from all other extinct and Recent members of the order by its distinctive head morphology and by unique spination of the metafemur and metatibia. Our new find sheds further light on the diversity and morphological disparity of fossil Zorapterans during the Late Mesozoic.
-
the first gynandromorph of a Zorapteran and potential thelytokous parthenogenesis in a population of zorotypus brasiliensis silvestri Zoraptera zorotypidae
Revista Brasileira De Entomologia, 2017Co-Authors: Jose Albertino Rafael, Michael S Engel, Dayse W A MarquesAbstract:Abstract The first gynandromorph of the insect order Zoraptera is reported. A gynandromorph of Zorotypus brasiliensis Silvestri is described from a likely parthenogenetic population in the Atlantic Forest around the border of the Brazilian states of Minas Gerais, Rio de Janeiro, and Sao Paulo. As has been previously surmised for this species, the sample consisted of only females, tending to support the hypothesis of thelytokous parthenogenesis for this population. The gynandromorph is largely female in outward appearance, but exhibits male secondary sexual traits on the left side of the apical abdominal segments. The left (male) antenna consists of antennomeres of different proportions to those of the right (female) antenna. The internal genitalia and associated sclerites, however, are female although some are augmented in their form relative to normal-type females. Comments are made on possible factors resulting in the development of the gynandromorph. This is the 16th insect order with gynandromorphism reported.
-
correction a unique box in 28s rrna is shared by the enigmatic insect order Zoraptera and dictyoptera
PLOS ONE, 2013Co-Authors: Yanhui Wang, Michael S Engel, Jose A Rafael, Kai Dang, Haoyang Wu, Ying Wang, Wenjun BuAbstract:The published Figure 3 is incorrect. Please view corrected Figure 3 here: There was an error with the first affiliation for author Michael S. Engel. The correct first affiliation is: Division of Entomology (Paleoentomology), Natural History Museum, University of Kansas, Kansas, USA
Romano Dallai - One of the best experts on this subject based on the ideXlab platform.
-
the morphology and ultrastructure of salivary glands of Zoraptera insecta
Arthropod Structure & Development, 2017Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The salivary glands of two species of Zoraptera, Zorotypus caudelli and Zorotypus hubbardi, were examined and documented mainly using transmission electron microscopy (TEM). The results obtained for males and females of the two species are compared and functional aspects related to ultrastructural features are discussed. The salivary glands are divided into two regions: the secretory cell region and the long efferent duct, the latter with its distal end opening in the salivarium below the hypopharyngeal base. The secretory region consists of a complex of secretory cells provided with microvillated cavities connected by short ectodermal ducts to large ones, which are connected with the long efferent duct. The secretory cell cytoplasm contains a large system of rough endoplasmic reticulum and Golgi apparatus producing numerous dense secretions. The cells of the efferent duct, characterized by reduced cytoplasm and the presence of long membrane infoldings associated with mitochondria, are possibly involved in fluid uptaking from the duct lumen.
-
the fine structure of the rectal pads of zorotypus caudelli karny Zoraptera insecta
Arthropod Structure & Development, 2016Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The rectal pads of a species of the controversial polyneopteran order Zoraptera were examined using histological sections and TEM micrographs. Six pads are present along the thin rectal epithelium. Each pad consists of a few large principal cells surrounded by flattened junctional cells, which extend also beneath the principal cells. The cells are lined by a thin apical cuticle. No basal cells and no cavity have been observed beneath the pad. Principal cells have a regular layer of apical microvilli and are joined by intercellular septate junctions, which are interrupted by short dilatations of the intercellular space. At these levels the two adjacent plasma membranes are joined by short zonulae adhaerentes. In the cytoplasm, a rich system of strict associations between lateral plasma membranes and mitochondria forms scalariform junctions. Rectal pads share ultrastructural features with similar excretory organs of several neopteran groups, in particular with Blattodea (roaches and termites) and Thysanoptera, and are involved in fluid reabsorption and ion regulation.
-
The evolution of insect sperm − an unusual character system in a megadiverse group
Journal of Zoological Systematics and Evolutionary Research, 2016Co-Authors: Marco Gottardo, David Mercati, Romano Dallai, Thomas Hörnschemeyer, Rolf G BeutelAbstract:Spermatozoa provide an unusual character system, with a limited number of components organized in a single cell. Similar spermatozoa occur in groups widely separated in the phylogenetic tree of Metazoa. Nevertheless, the character system contains phylogenetic information. Hexapoda have acquired spermatophores along with the switch from aquatic to terrestrial habitats, and related to this, a multitude of different sperm types. The aim of this study is a formal evaluation of the phylogenetic information content of spermatozoa. For the first time, sperm characters are coded for formal phylogenetic analyses. Different approaches are used and compared. Mainly due to a high level of homoplasy, the evaluation of sperm characters alone is insufficient for a reconstruction of the phylogeny of the group. Yet, a reliable reconstruction of the evolution of insect sperm is possible when character transformations are assessed using a phylogeny based on extensive molecular data. Important changes took place in the early evolution of Hexapoda. Sperm characters support some major clades (e.g. Hexapoda, Dicondylia, Polyneoptera, Psocodea), but important steps in the evolution are not reflected by transformations of spermatozoa, notably the rise of Pterygota or Holometabola. Important innovations are the formation of mitochondrial derivatives and the acquisition of accessory microtubules. Some features are conservative, whereas others evolved rapidly (e.g. presence or absence of the acrosome vesicle). Some groups are conservative in their sperm features (e.g. Odonata, Heteroptera), whereas the evolution of spermatozoa was distinctly accelerated in others (e.g. Ephemeroptera). The rate of evolution can change drastically in closely related groups. Profound changes in the morphologically uniform Zoraptera underline that sperm evolution can follow a pattern very different from the general somatic morphology. The mode of character reconstruction preferred here will be useful for the evaluation of specialized morphological character systems and strengthen the concept of evolutionary morphology.
-
Structure and Evolution of Insect Sperm: New Interpretations in the Age of Phylogenomics.
Annual Review of Entomology, 2016Co-Authors: Romano Dallai, Marco Gottardo, Rolf Georg BeutelAbstract:This comprehensive review of the structure of sperm in all orders of insects evaluates phylogenetic implications, with the background of a phylogeny based on transcriptomes. Sperm characters strongly support several major branches of the phylogeny of insects-for instance, Cercophora, Dicondylia, and Psocodea-and also different infraordinal groups. Some closely related taxa, such as Trichoptera and Lepidoptera (Amphiesmenoptera), differ greatly in sperm structure. Sperm characters are very conservative in some groups (Heteroptera, Odonata) but highly variable in others, including Zoraptera, a small and morphologically uniform group with a tremendously accelerated rate of sperm evolution. Unusual patterns such as sperm dimorphism, the formation of bundles, or aflagellate and immotile sperm have evolved independently in several groups.
-
the morphology of the eggs of three species of Zoraptera insecta
Arthropod Structure & Development, 2015Co-Authors: Yuta Mashimo, Rolf Georg Beutel, Marco Gottardo, Romano Dallai, Ryuichiro MachidaAbstract:The egg structure of Zorotypus magnicaudelli, Zorotypus hubbardi and Zorotypus impolitus was examined and described in detail. Major characteristics of Zorapteran eggs previously reported were confirmed in these species, with the partial exception of Z. impolitus: 1) a pair of micropyles at the equator of the egg's ventral side, 2) a honeycomb pattern on the egg surface, 3) a two-layered chorion, 4) micropylar canals running laterally, 5) a flap covering the inner opening of the micropylar canal and 6) no region specialized for hatching. These features are probably part of the groundplan of the order. Three groups (A–C) and two subgroups (A1 and A2) of Zoraptera can be distinguished based on characters of the reproductive apparatus including eggs. However, information for more species is needed for a reliable interpretation of the complex and apparently fast evolving character system. The egg of Z. impolitus presumably shows apomorphic characteristics not occurring in other species, a chorion without layered construction and polygonal surface compartments with different sculptures on the dorsal and ventral sides of the egg. Another feature found in this species, distinct enlargement of the micropyles, is also found in Z. hubbardi. The increased micropylar size is likely correlated with the giant spermatozoa produced by males of these two species. These two features combined with the large size of the spermatheca are arguably a complex synapomorphy of Z. hubbardi and Z. impolitus. The phylogenetic placement of Zoraptera is discussed based on the egg structure. A clade of Zoraptera + Eukinolabia appears most plausible, but the issue remains an open question.
Yuta Mashimo - One of the best experts on this subject based on the ideXlab platform.
-
zorotypus pecten a new species of Zoraptera insecta from mid cretaceous burmese amber
Zootaxa, 2019Co-Authors: Yuta Mashimo, Patrick Muller, Rolf Georg BeutelAbstract:: A new species of the order Zoraptera, Zorotypus pecten sp. n., is described from mid-Cretaceous Burmese amber. It is tentatively assigned to the subgenus Octozoros based on 8-segmented antenna. A Gondwanan origin for Zoraptera is discussed based on the geographic distribution of extant and fossil Zorapterans.
-
the hairy beast zorotypus hirsutus sp n an unusual new species of Zoraptera insecta from burmese amber
Zootaxa, 2018Co-Authors: Yuta Mashimo, Patrick Muller, Hans Pohl, Rolf Georg BeutelAbstract:A new species of the order Zoraptera, Zorotypus hirsutus Mashimo sp. n., is described from mid-Cretaceous Burmese amber. The specimen is tentatively assigned to the subgenus Octozoros Engel based on number of antennomeres reduced from nine to eight. It is characterized by an unusually strong setation, appearing much more hirsute than other extant or extinct species of the order. Other unusual autapomorphic features are an elongated head capsule with a concave genal region and very slender, elongate antennomeres. The discovery of this aberrant species suggests that the morphological diversity of Zoraptera was much higher than previously expected. For a reliable placement of Zorotypus hirsutus the discovery of males and a robust species level phylogeny would be required.
-
a remarkable new species of Zoraptera zorotypus asymmetristernum sp n from kenya insecta Zoraptera zorotypidae
Zootaxa, 2018Co-Authors: Yuta Mashimo, Yoko Matsumura, Rolf Georg Beutel, Laban Njoroge, Ryuichiro MachidaAbstract:A new species of order Zoraptera, Zorotypus asymmetristernum Mashimo, n. sp., is described from Kakamega, Kenya, with its major diagnostic features and characteristics of the egg described and illustrated. The new species represents the sixth Zorapteran species from the Afrotropic ecozone. A brief discussion on vestigial eye spots of apteron individuals and a key to the species of the Afrotropic ecozone are provided.
-
the morphology and ultrastructure of salivary glands of Zoraptera insecta
Arthropod Structure & Development, 2017Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The salivary glands of two species of Zoraptera, Zorotypus caudelli and Zorotypus hubbardi, were examined and documented mainly using transmission electron microscopy (TEM). The results obtained for males and females of the two species are compared and functional aspects related to ultrastructural features are discussed. The salivary glands are divided into two regions: the secretory cell region and the long efferent duct, the latter with its distal end opening in the salivarium below the hypopharyngeal base. The secretory region consists of a complex of secretory cells provided with microvillated cavities connected by short ectodermal ducts to large ones, which are connected with the long efferent duct. The secretory cell cytoplasm contains a large system of rough endoplasmic reticulum and Golgi apparatus producing numerous dense secretions. The cells of the efferent duct, characterized by reduced cytoplasm and the presence of long membrane infoldings associated with mitochondria, are possibly involved in fluid uptaking from the duct lumen.
-
the fine structure of the rectal pads of zorotypus caudelli karny Zoraptera insecta
Arthropod Structure & Development, 2016Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The rectal pads of a species of the controversial polyneopteran order Zoraptera were examined using histological sections and TEM micrographs. Six pads are present along the thin rectal epithelium. Each pad consists of a few large principal cells surrounded by flattened junctional cells, which extend also beneath the principal cells. The cells are lined by a thin apical cuticle. No basal cells and no cavity have been observed beneath the pad. Principal cells have a regular layer of apical microvilli and are joined by intercellular septate junctions, which are interrupted by short dilatations of the intercellular space. At these levels the two adjacent plasma membranes are joined by short zonulae adhaerentes. In the cytoplasm, a rich system of strict associations between lateral plasma membranes and mitochondria forms scalariform junctions. Rectal pads share ultrastructural features with similar excretory organs of several neopteran groups, in particular with Blattodea (roaches and termites) and Thysanoptera, and are involved in fluid reabsorption and ion regulation.
Ryuichiro Machida - One of the best experts on this subject based on the ideXlab platform.
-
a remarkable new species of Zoraptera zorotypus asymmetristernum sp n from kenya insecta Zoraptera zorotypidae
Zootaxa, 2018Co-Authors: Yuta Mashimo, Yoko Matsumura, Rolf Georg Beutel, Laban Njoroge, Ryuichiro MachidaAbstract:A new species of order Zoraptera, Zorotypus asymmetristernum Mashimo, n. sp., is described from Kakamega, Kenya, with its major diagnostic features and characteristics of the egg described and illustrated. The new species represents the sixth Zorapteran species from the Afrotropic ecozone. A brief discussion on vestigial eye spots of apteron individuals and a key to the species of the Afrotropic ecozone are provided.
-
the morphology and ultrastructure of salivary glands of Zoraptera insecta
Arthropod Structure & Development, 2017Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The salivary glands of two species of Zoraptera, Zorotypus caudelli and Zorotypus hubbardi, were examined and documented mainly using transmission electron microscopy (TEM). The results obtained for males and females of the two species are compared and functional aspects related to ultrastructural features are discussed. The salivary glands are divided into two regions: the secretory cell region and the long efferent duct, the latter with its distal end opening in the salivarium below the hypopharyngeal base. The secretory region consists of a complex of secretory cells provided with microvillated cavities connected by short ectodermal ducts to large ones, which are connected with the long efferent duct. The secretory cell cytoplasm contains a large system of rough endoplasmic reticulum and Golgi apparatus producing numerous dense secretions. The cells of the efferent duct, characterized by reduced cytoplasm and the presence of long membrane infoldings associated with mitochondria, are possibly involved in fluid uptaking from the duct lumen.
-
the fine structure of the rectal pads of zorotypus caudelli karny Zoraptera insecta
Arthropod Structure & Development, 2016Co-Authors: Romano Dallai, David Mercati, Yuta Mashimo, Ryuichiro Machida, Rolf Georg BeutelAbstract:Abstract The rectal pads of a species of the controversial polyneopteran order Zoraptera were examined using histological sections and TEM micrographs. Six pads are present along the thin rectal epithelium. Each pad consists of a few large principal cells surrounded by flattened junctional cells, which extend also beneath the principal cells. The cells are lined by a thin apical cuticle. No basal cells and no cavity have been observed beneath the pad. Principal cells have a regular layer of apical microvilli and are joined by intercellular septate junctions, which are interrupted by short dilatations of the intercellular space. At these levels the two adjacent plasma membranes are joined by short zonulae adhaerentes. In the cytoplasm, a rich system of strict associations between lateral plasma membranes and mitochondria forms scalariform junctions. Rectal pads share ultrastructural features with similar excretory organs of several neopteran groups, in particular with Blattodea (roaches and termites) and Thysanoptera, and are involved in fluid reabsorption and ion regulation.
-
the morphology of the eggs of three species of Zoraptera insecta
Arthropod Structure & Development, 2015Co-Authors: Yuta Mashimo, Rolf Georg Beutel, Marco Gottardo, Romano Dallai, Ryuichiro MachidaAbstract:The egg structure of Zorotypus magnicaudelli, Zorotypus hubbardi and Zorotypus impolitus was examined and described in detail. Major characteristics of Zorapteran eggs previously reported were confirmed in these species, with the partial exception of Z. impolitus: 1) a pair of micropyles at the equator of the egg's ventral side, 2) a honeycomb pattern on the egg surface, 3) a two-layered chorion, 4) micropylar canals running laterally, 5) a flap covering the inner opening of the micropylar canal and 6) no region specialized for hatching. These features are probably part of the groundplan of the order. Three groups (A–C) and two subgroups (A1 and A2) of Zoraptera can be distinguished based on characters of the reproductive apparatus including eggs. However, information for more species is needed for a reliable interpretation of the complex and apparently fast evolving character system. The egg of Z. impolitus presumably shows apomorphic characteristics not occurring in other species, a chorion without layered construction and polygonal surface compartments with different sculptures on the dorsal and ventral sides of the egg. Another feature found in this species, distinct enlargement of the micropyles, is also found in Z. hubbardi. The increased micropylar size is likely correlated with the giant spermatozoa produced by males of these two species. These two features combined with the large size of the spermatheca are arguably a complex synapomorphy of Z. hubbardi and Z. impolitus. The phylogenetic placement of Zoraptera is discussed based on the egg structure. A clade of Zoraptera + Eukinolabia appears most plausible, but the issue remains an open question.
-
The intermediate sperm type and genitalia of Zorotypus shannoni Gurney: evidence supporting infraordinal lineages in Zoraptera (Insecta)
Zoomorphology, 2015Co-Authors: Romano Dallai, Yoko Matsumura, David Mercati, Yuta Mashimo, Ryuichiro Machida, Marco Gottardo, Jose Albertino Rafael, Rolf Georg BeutelAbstract:The sperm ultrastructure and the male and female genital apparatus of Zorotypus shannoni were examined and documented in detail, mainly using transmission electron microscopy micrographs. The findings suggest an evolutionary trend shared with Z. hubbardi and Z. impolitus . The three species are characterized by enlarged mitochondrial derivatives and related modifications. Giant sperm are probably a synapomorphy of Z. hubbardi and Z. impolitus , whereas an intermediate condition of this feature is found in Z. shannoni. The monophyletic origin of Z. caudelli , Z. magnicaudelli , Z. huxleyi and Z. weidneri is suggested by characteristically modified axonemes. The presence of extra-acrosomal material is also an unusual feature for Zoraptera, but this condition also occurs in the majority of polyneopteran groups. The long and convoluted female spermathecal duct with secretory and duct-forming cells is a constant feature in Zoraptera. The enlarged seminal receptacle suggests an evolutionary link between the male genital structures and the sperm size on one hand, and the size of the female spermatheca on the other. The small and otherwise uniform group Zoraptera exhibits a remarkable variation of sperm types and genital structures, suggesting the impact of different types of selection. It is likely that cryptic female choice plays a major role in shaping the genital apparatus.