1,721,045 research outputs found
Morphological characterization of female accessory sex glands of Eupolybothrus fasciatus (Newport) (Chilopoda Lithobiomorpha)
No full textThe female reproductive system of Eupolybothrus fasciatus (Newport) (Chilopoda Lithobiomorpha) includes three types of well-developed accessory glands, viz. large glands, small glands, and the periatrial gland. External morphology and the ultrastructural organization of these glands have been investigated by light and electron microscopy. The small and large glands are paired and have coiled ducts that open, respectively, into and externally to the genital atrium. By contrast, the periatrial gland is unpaired and is located on the ventral wall of the atrium into which it opens via several small canals. Ultrastructural features show that all three glands consist of two different types of cells: secretory cells and ductule cells. The secretory cells contain prominent secretory granules and are similar to a class of insect epidermal gland cells (class 3) organized as acini surrounding an extracellular lumen into which microvilli project. The granules, which have different morphological features in each gland, could be responsible for important differential functions such as producing a sexual attractant, providing a coating material that protects eggs laid on the ground, and contributing to a fluid that digests spermatophores. (C) 1996 Wiley-Liss, Inc
New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama
No full textCurini-Galletti, Marco, Carcupino, Marcella, Stocchino, Giacinta A., Leasi, Francesca, Norenburg, Jon L. (2020): New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama. Zootaxa 4881 (3): 482-498, DOI: 10.11646/zootaxa.4881.3.
Implication of male reproductive apparatus morphology for the insemination modality of the Syngnathus abaster (Teleostei, Syngnatidae [Syngnathidae]). FT Implicazioni della morfologia dell'apparato riproduttore maschile nella modalita d'inseminazione in Syngnathus abaster (Teleostei, Syngnatidae).
No full textThe aim of this study is contribute to clarify some important aspects of the reproductive biology of the fish family Syngnathidae (pipefishes and seahorses), such as the sperm transfer and fertilisation strategy throughout the morphological analysis of the male reproductive apparatus: data on the genital ducts openings and testis structure in Syngnathus abaster (internal brooders species) are reported. Z9
New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama
No full textCurini-Galletti, Marco, Carcupino, Marcella, Stocchino, Giacinta A., Leasi, Francesca, Norenburg, Jon L. (2020): New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama. Zootaxa 4881 (3): 482-498, DOI: https://doi.org/10.11646/zootaxa.4881.3.
ULTRASTRUCTURE OF THE SPERMATOZOON OF ELENCHUS-JAPONICUS AND ITS BEARING ON THE PHYLOGENY OF STREPSIPTERA
No full textThe fine structure of the mature spermatozoon of the strepsipteran Elenchus japonicus Esaki and Hashimoto (Elenchidae) is described using transmission electron microscopy. The spermatozoon was seen to have an elongated head. a tail containing a 9+9+2 axoneme, two mitochondrial derivatives and two accessory sheaths. The monolayered acrosome is conical in shape while the nucleus exhibits an internal channel of uncondensed chromatin. The tail is long, and in its final portion, the axoneme, loses its elements progressively. These results are compared with the sperm ultrastructurc of Xenos moutoni De Buysson (Stylopidae) and with those of other insect orders, particularly the Coleoptera
Spermiogenesis in Chalcides ocellatus tiligugu (Gmelin) (Squamata, Scincidae): an electron microscope study
No full textOOTAXONOMIC INVESTIGATION OF 3 SPECIES OF MYCOMYA (DIPTERA, MYCETOPHILIDAE) - A SCANNING ELECTRON-MICROSCOPE STUDY
No full textThe egg-shell structure of three fungus-gnat species of the genus Mycomya (M. occultans, M. marginata, M. fimbriata) was investigated by scanning electron microscope (SEM). Each species, pear-shaped with a single micropyle located at a pole, shows some distinctive characters in egg morphology, namely different egg shape and size, together with chorionic sculpturing of the micropylar area, egg surface and a specialized ventral area. The latter, interpreted as a plastron, is detected for the first time in the eggs of Mycomyinae. Ootaxonomic data of these species are compared with those of other Diptera and discussed in relation to adult behaviour and the microclimatic conditions of the laying biotope
EGG CHORION ARCHITECTURE IN STICK INSECTS (PHASMATODEA)
No full textComparative analysis of egg chorion architecture by scanning and transmission electron microscopy is reported in about 50 species of stick insects (Phasmatodea). Particular attention has been paid to: (1) synthesis and structure of egg shell layers; (2) egg shape; (3) morphology of the external chorionic surface; (4) position and structure of the micropylar plate and its cup; (5) morphology and details of the operculum, including capitulum or pseudocapitulum; and (6) posterior pole differentiation (the so-called polar mound). The taxonomic value of the various characters is discussed: some are clearly species-specific, while others (such as general egg shape and micropylar plate) appear to reflect phylogenetic relationships of higher rank. Intraspecific features, such as the fine chorionic and opercular patterns of Bacillus and Clonopsis, have been recognized. In natural hybrids, egg chorion architectures were related to that of the parent species, resembling one of the parents in some cases and being intermediate between the 2. The study of the Phasmatodea egg can provide much taxonomic information that is useful in the definition of natural groups
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