bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comments on the morphology of the pre‐oral spine in Argulus (Crustacea: Branchiura)
Authors: Swanepoel J. H. , Avenant‐Oldewage Annemarie 
Published: February 2005

AbstractA histological study of the pre‐oral spine and associated structures in Argulus japonicus reveals that two exceptionally long and slender muscles casuse retraction of the spine into the spinal sheath. Originating from the body wall mid‐dorsally the two muscles proceed through the nerve ring and the blood‐filled lumen of the spinal sheath before being inserted on a bolster of tissue constituting the base of the spine. Movement of the spinal sheath is affected by two muscles originating from a common apodeme in the dorsal body wall, just posterior to the nauplius eye, and inserted on the lateral walls of the base of the spinal sheath.Two ducts, each leading from a glandular complex in the lateral parts of the carapace, proceed rostrally through the haemocoelic spaces. After passing the tritocerebrum laterally they accompany the retractor muscles of the spine on their course to the base of the spine. Passing through the bolster of tissue at the base of the spine the two ducts run all the way up to the tip of the spine where they open separately.The glandula praeboscoidalis is not associated with the pre‐oral spine since its duct runs posteriorly in the wall of the proboscis. The labial spines are associated with giant glandular cells located beneath the optic tracts. © 1992 Wiley‐Liss, Inc.
Morphology of the antennae of two species of biting midge: Culicoides impunctatus (goetghebuer) and Culicoides nubeculosus (Meigen) (Diptera, Ceratopogonidae)
Authors: Blackwell Alison , Mordue (Luntz) A. Jennifer , Mordue William 
Published: February 2005

AbstractScanning and transmission electron microscopy of the antennae of Culicoides impunctatus and Culicoides nubeculosus show that males and females share five sensillum types. Sensilla chaetica resemble mechanoreceptors, each innervated by a single neurone whose dendrite terminates distally in a tubular body: the arrangement of sensilla on male antennae suggests that females are located by sound. The antennae have both sharp‐ and blunt‐tipped sensilla trichodea, sharp‐tipped sensilla on only the distal third and blunttipped sensilla on all subsegments. These sensilla are typical of olfactory receptors, having multiporous walls and being innervated by a number of neurones with bifurcating dendrites ascending the hair shafts. Sensilla basiconica occur on the distal five subsegments of the female antenna and the distal three subsegments of the male antenna. Sensilla coeloconica always occur on subsegment one and sometimes on a number of other subsegments, depending on sex and species. Both basiconic and coeloconic sensilla have double walls and unbranched dendrites and may be either olfactory or thermo‐ and/or hygroreceptors. All antennae except those of male C. impunctatus antennae have sensilla ampullacea, apparently deep‐seated olfactory or thermoreceptors. Small peg sensilla fitting the description of contact chemoreceptors occur only at the tip of the male antenna. © 1992 Wiley‐Liss, Inc.
Morphological corollaries and ecological implications of flightlessness in the kakapo (Psittaciformes: Strigops habroptilus)
Authors: Livezey Bradley C. 
Published: February 2005

AbstractThe morphological corollaries of flightlessness of the kakapo (Strigops habroptilus) have been studied using skin specimens, skeletons, and pectoral dissection of an anatomical specimen. These have been compared with the closely related, flighted kea (Nestor notabilis), and secondarily with other Psittaciformes and the convergent hoatzin (Cuculiformes: Opisthocomus hoazin). S. habroptilus is the most massive and sexually dimorphic psittaciform in the world, and has the smallest relative wing size of any parrot. Alar pterylography of S. habroptilus is similar to that of other parrots, but remiges of the species are shorter, comparatively rounded, show less asymmetry of vanes, and have fewer interlocking barbules distally. S. habroptilus shows peculiarities of the sternum (vestigial carina, shortened spina externa), coracoid (elongate processus lateralis, enlarged angle with scapula), and humerus (prominent tuberculum ventrale, undercut crista bicipitalis). Pectoral skeletal dimensions of S. habroptilus are smaller than those of N. notabilis, whereas the reverse is true for pelvic dimensions. Most skeletal dimensions of S. habroptilus are more variable (within sexes) than those of N. notabilis. Proximal wing elements are disproportionately long and distal elements disproportionately short in S. habroptilus. The legs of S. habroptilus are characterized by disproportionately long femora and disproportionately short tarsometatarsi. Distinctive features of the pectoral musculature of S. habroptilus include a greatly reduced Mm. pectoralis thoracica and supracoracoideus, the absence of a distinct proximal muscle belly of M. propatagialis tendo longus, an extensive M. cucullaris capitis clavicularis associated with a voluminous crop, and an essentially tendinous M. sternocoracoideus. Relative to mean body mass, all dimensions of the antebrachial, carpometacarpal, digital, and patagial muscles are smaller in S. habroptilus than in N. notabilis. These aspects are compared to those of other flightless birds. Discussed are implications of flightlessness and associated large body size of S. habroptilus for issues of thermodynamics, metabolism, activity patterns, digestive anatomy, diet, reproduction, and insularit. © 1992 Wiley‐Liss, Inc.
Programmed cell death and heterolysis of larval epithelial cells by macrophage‐like cells in the anuran small intestine in vivo and in vitro
Authors: Ishizuya‐Oka Atsuko , Shimozawa Atsumi 
Published: February 2005

AbstractThe degenerative processes in the larval small intestine of Xenopus laevis tadpoles during spontaneous metamorphosis and during thyroid hormone‐induced metamorphosis in vitro were examined by electron microscopy. Around the beginning of spontaneous metamorphic climax (stages 59–61), both apoptotic bodies derived from larval epithelial cells and intraepithelial macrophage‐like cells suddenly increase in number. The macrophage‐like cells become rounded and enlarged because of numerous vacuoles containing the apoptotic bodies. Mitotic profiles of the macrophage‐like cells, however, are localized in the connective tissue where different developmental stages of macrophage‐like cells are present. After stage 62, the intraepithelial macrophage‐like cells decrease in number, while large macrophage‐like cells which include the apoptotic bodies and retain intact cell membranes and nuclei appear in the lumen. Degenerative changes similar to those during spontaneous metamorphosis described above could be reproduced in vitro. In tissue fragments isolated from the small intestine of stage 57 tadpoles and cultured in the presence of thyroid hormone, the number of intraepithelial macrophage‐like cells reaches its maximum around the 3rd day of cultivation when the larval epithelial cells most rapidly decrease in number. These results suggest that the rapid degeneration of larval epithelial cells occurs not only because of apoptosis of the epithelial cells themselves but also from heterolysis by macrophages. The macrophages probably originate in the connective tissue, actively proliferate, migrate into the larval epithelium around the beginning of metamorphic climax, and are finally extruded into the lumen. © 1992 Wiley‐Liss, Inc.
The development of Caretta caretta, at 25–34°C, in artificial nests
Authors: Billett F. S. , Collins P. , Goulding D. A. , Sutherland J. 
Published: February 2005

AbstractScanning electron microscopy has been used to enhance the description of a single species, Caretta caretta (the loggerhead turtle), staged according to Miller's system for the development of marine turtles. Incubation over a temperature range of 25°–34°C confirms previous observations that, under artificial conditions and at a constant incubation temperature, normal development is confined to a limited temperature range. Premature pipping is a feature of incubation at the lower end of this range; abnormal development, generated during the first third of the incubation period, occurs just above the normal range. Details of the external morphology of embryos from Miller stage 14 through to 25 are given together with an account of the developmental abnormalities produced at a high temperature of incubation. The data obtained confirm that Miller's scheme is generally applicable to C. caretta, provided that due regard is paid to the incubation temperature. © 1992 Wiley‐Liss, Inc.
Influence of web‐monitoring tactics on the density of mitochondria in leg muscles of the spider family uloboridae
Authors: Opell Brent D. , Konur David C. 
Published: February 2005

AbstractFrom electron micrographs we determined the ratio of mitochondrial to myofibril cross sectional area in cells of the first leg anterior depressor muscles of adult females of four spider species, each from a different genus. Species with more active web‐monitoring tactics and greater tracheal supplies to their first legs have muscle cells that are better supplied with mitochondria than those with less active tactics and less well‐developed tracheal systems. These results demonstrate that, even in homologous tissues of closely related species, mitochondrial supply can change to accommodate changes in metabolic activity. © 1992 Wiley‐Liss, Inc.
Anatomy of synganglia, including their neurosecretory regions, in unfed, virgin female Ixodes scapularis say (Acari: Ixodidae)
Authors: Szlendak Ewa , Oliver James H. 
Published: February 2005

AbstractThe central nervous system of Ixodes scapularis is fused into a single compact synganglion. The esophagus runs through the synganglion and divides it into supraesophageal and subesophageal parts. The supraesophageal portion contains a single protocerebrum with four pairs of glomeruli, paired optic lobes and cheliceral ganglia, and a single stomodeal bridge. The subesophageal portion contains a centrally located network of commissures and connectives, a pair of palpal ganglia, paired olfactory lobes of the first pedal ganglia, four pairs of pedal ganglia, and a single opisthosomal ganglion. A retrocerebral organ complex (ROC) in close vicinity of the digestive tract, as described in some other tick species, apparently is lacking. Perhaps the function of the ROC is performed by the paired, large, ganglion‐like bodies that lie anterolaterad to the cheliceral ganglia.The rind, which is formed from the neuronal somata and glial cells, surrounds the central fibrous core or neuropile. Neurosecretory cells (NSC) are distinct among rind cells due to their large size and concentration of cytoplasmic neurosecretions. NSC are present throughout the synganglion, although the subesophageal portion contains larger groups of these cells. Histological serial sections, stained with Meola's (Trans Am Microsc Soc 89:66–71, '70) paraldehyde fuchsin (PAF) procedure revealed 24 PAF‐stained, putative neurosecretory regions in the synganglion of virgin, unfed females. All of these regions appear to be connected and associated with the nearest ganglion and are correspondingly named. Eighteen PAF‐positive regions occur in the synganglion. In addition, PAF‐negative (green‐stained) cells occupy 6 distinct regions in the synganglion of unfed, unmated females. © 1992 Wiley‐Liss, Inc.
Three nephromixial patterns in polychaete species currently assigned to the genusPista(Annelida, Terebellidae)
Authors: Smith Ralph I. 
Published: February 2005

AbstractA comparative morphological study of nephromixial systems in three Californian terebellid polchaetes currently assigned to the genusPistashows thatP. fimbriatahas all attributes of the generic type, but thatP. pacificaandP. elongatadiffer markedly. The features of typicalPistainclude (among others): two pairs of usually unequal branchiae, long‐handled anterior uncini (hooks) of crested avicular (bird‐head‐like) from, muddy, unornamented tubes, one pair of anterior excretory nephromixia (ENMX), and two pairs of separate thoracic reproductive nephromixia (RNMX) with genital papillae on segments VI and VII. A review indicates thatP. fimbriatashares these typical features with practically all adequately describedPistaspecies. However,P. pacificaandP. elongatapossess three pairs of branchiae, long‐handled uncini of distinctive crochet‐like form, and membranous tubes with apertural hoods. Both have two pairs of ENMX, the first supplied by one pair of ciliated renal funnels, the second by two pairs of such funnels. But they differ in their RNMX:P. pacificahas three pairs of complex RNMX, those on each side united by a common duct.P. elongatahas 11–13 pairs of simple RNMX united by common ducts. Although these species do not fit intoPista, no genus has been found to accommodate them. Generic placement is complicated by the fact that no instances of intra‐generic nephromixial variation have been reported in the Terebellidae, although inter‐generic variation is well known. If they are congeneric, this would be the first example of intrageneric RNMX variation in Terebellidae. But if assigned to separate genera or subgenera on the basis of their RNMX, their similarity of anterior uncini might be attributable to parallel or convergent adaptation to life in comparable tubes. More evidence, including molecular analysis, is needed for phylogenetic studies of Terebellidae. © 1992 Wiley‐Liss, Inc.
Skeletal development in Xenopus laevis (Anura: Pipidae)
Authors: Trueb Linda , Hanken James 
Published: February 2005

AbstractPostembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared‐and‐stained whole‐mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46–65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that the timing, but not the sequence, of skeletal development in X. laevis is more variable than previously reported and poorly correlated with the development of external morphology. Examination of chondrocranial development indicates that the rostral cartilages of X. laevis are homologous with the suprarostral cartilages of non‐pipoid anurans, and suggests that the peculiar chondrocranium of this taxon is derived from a more generalized pattern typical of non‐pipoid frogs. Derived features of skeletal development not previously reported for X. laevis include (1) bipartite formation of the palatoquadrate; (2) precocious formation of the adult mandible; (3) origin of the angulosplenial from two centers of ossification; (4) complete erosion of the orbital cartilage during the later stages of metamorphosis; (5) development of the sphenethmoid as a membrane, rather than an endochondral bone; and (6) a pattern of timing of ossification that more closely coincides with that of the pelobatid frog Spea than that recorded for neobatrachian species. © 1992 Wiley‐Liss, Inc.
Differences in morphological features of the sacculus of the inner ear of two hakes (Merluccius capensis and M. paradoxus, gadiformes) inhabits from different depth of sea
Authors: Lombarte Antoni , Fortuño José M. 
Published: February 2005

AbstractThe morphology of the sensory epithelia of the sacculus in two species of hake, Merluccius capensis and M. paradoxus, was analyzed by scanning electron microscopy (SEM). The sensory epithelia have two morphological features that are very different from other gadiform species. These include the presence of two large areas which are only linked by a narrow neck, and the larger proportion of hair cells oriented in the rostrocaudal axis than in other species. The deeper‐dwelling species, M. paradoxus, has a larger proportion of hair cell with short ciliary bundles than does the shallower‐dwelling species, M. capensis. These morphological specializations could improve the acoustic diserimination and localization capabilities of these species, possibly related to an increase in sensitivity to higher frequency sounds in the deeper‐dwelling species. © 1992 Wiley‐Liss, Inc.
Muscles of the pelvic outlet in the fowl (Gallus gallus domesticus) with special reference to their nerve supply
Authors: Akita Keiichi , Sakamoto Hirokazu , Sato Tatsuo 
Published: February 2005

AbstractThe manner of innervation of the pelvic outlet muscles in fowl (Gallus gallus domesticus) was examined in detail in four male pelvic halves. The segmental arrangement of the nerve supply in the sacral and pudendal plexuses was compared to that of Lacertilia and Urodela as a basis for a morphologiccal analysis of the pelvic outlet muscles. From the viewpoint of innervation, the pelvic outlet muscles of fowl are classified into two groups: a sphincter muscle group and a levator muscle group. These two groups are closely related to the ventral muscles of the pelvic limb. In contrast to the morphology of pelvic outlet muscles in lacertilians, in fowl the caudal muscle element does not contribute to the formation of these muscles. © 1992 Wiley‐Liss, Inc.
Natural and experimental reduction of the avian fibula: Developmental thresholds and evolutionary constraint
Authors: Streicher Johannes , Müller Gerd B. 
Published: February 2005

AbstractFibula reduction is a key feature of avian limb evolution. In a combined comparative and experimental approach the present study analyses the trends of fibula reduction in extant birds and their developmental basis. The study of 55 species of birds reveals four different types of tibiotarsus‐to‐fibula relationships. Extremely small fibulae are associated with two types of limb modification: (1) elongations of the limb primarily affect the tibiotarsus, increasing its length more than that of the fibula; (2) miniaturizations of the limb reduce both tibiotarsus and fibula length, but are reglarly associated with structural reductions of the distal parts of the fibula. True structrual reductions are distinguished from relative size reductions. The specific features of fibula reduction are analyzed through experimental mesenchyme excisions in chick limb buds. The methodical variation of experimental parameters resolves a long‐standing controversy about the effects of mesenchyme reductions on the patterns of skeletal formation. Mesenchyme excisions are shown to have unequal effects on the two zeugopod bones, affecting the fibula to a greater degree than the tibiotarsus. Several of the features seen in birds with advanced fibula reductions are paralleled by the effects of mesenchyme reductions. The consequences of this differential susceptibility of the skeletal blastemata are discussed both in terms of pattern formation in limb development and in terms of its bearing on the patterns of evolutionary limb reduction. It is concluded that thresholds of cell number and blastema size in development constrain the patterns of phenotypic variation in avian limbs. © 1992 Wiley‐Liss, Inc.
Fine structure of the skin of the amphibious fishes, Boleophthalmus pectinirostris and Periophthalmus cantonensis, with special reference to the location of blood vessels
Authors: Yokoya Sachihiko , Tamura Osamu S. 
Published: February 2005

AbstractThe skin of the amphibious fishes, Periophthalmus cantonensis and Boleophthalmus pectinirostris, was investigated by transmission electron microscopy (TEM). In both species the epidermis consists of superficial nonvacuolated epithelial cells, swollen epithelial cells with membrane limited cytoplasmic vacuoles, and basal epithelial cells in a single layer. Unicellular mucous glands, but no chloride cells are found in the epidermis of B. pectinirostris; in contrast there are chloride cells and no unicellular mucous cells in P. cantonensis. Intraepidermal blood vessels are a notable feature in the epidermis of P. cantonensis. Capillaries are distributed near the epidermal surface, offering an air‐blood barrier of sufficient thinness (2–4 μm) for cutaneous respiration. The large blood vessels (arterioles and venules) are seen in the middle stratum of the epidermis and seem to be able to regulate blood flow in the skin. In B. pectinirostris, the dermal capillaries lie immediately below the superficial epithelial cells at the apex of a dermal bulge where the air‐blood barrier is almost as thin as that of P. cantonensis despite locally different histology. In the spacious dermal bulges, the dermal tissue such as blood vessels, pigment cells, fibroblasts, and collagen fibers are scattered. Melanophores and two other types of chromatophores occur in the part adjacent to the blood vessel wall. The organization of the epidermis and blood vessels of the skin is discussed with regard to terrestrial life in these amphibious fishes. © 1992 Wiley‐Liss, Inc.
Sensilla on the mouthparts and antennae of the elephant louse, Haematomyzus elephantis piaget (Phthiraptera: Haematomyzidae)
Authors: Baker Gerald T. , Chandrapatya Angsumarn 
Published: February 2005

AbstractThe labial palpus of the elephant louse Haematomyzus elephantis has six sensilla that represent three different types: trichoid, basiconic, and styloconic. Two rows of basiconic sensilla are situated on the dorsal and ventral surfaces of the rostrum, and each row consists of three sensilla. Male and female antennae have 15–17 trichoid sensilla situated on the scape, pedicel, and three antennal annuli. Both sexes have two sensilla basiconica on the dorsal surface of the pedicel near the junction of the scape and pedicel. Two coeloconic (tuft) sensilla are situated on the antennae of both sexes, one sensillum on each of the last two annuli. There are three plate organs, two on the last annulus and one on the penultimate annulus of the male and female antennae. Sexual dimorphism is exhibited in the male and female antennae, in that the male has about twice as many sensilla basiconica on the apex of the last annulus as does the female. The total number of sensilla basiconica on the apex of the male antennae is at least two times the number that is known to be present in any other species of lice. © 1992 Wiley‐Liss, Inc.