bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional analysis of a specialized prey processing behavior: Winnowing by surfperches (Teleostei: Embiotocidae)
Authors: Drucker Eliot G. , Jensen Jeffrey S. 
Published: February 2005

AbstractSeveral surfperches (Embiotocidae), including the black surfperch, Embiotoca jacksoni, exhibit a specialized prey handling behavior known as winnowing, in which ingested food and non‐nutritive debris are separated within the oropharyngeal cavity. Prey items are swallowed, and unpalatable material is ejected from the mouth. Winnowing is believed to play an important role in the partitioning of food resources among sympatric embiotocids. We present a mechanistic model for this separative prey processing based on high‐speed video analysis, cineradiography, electromyography, and buccal and opercular cavity pressure transducer recording.Winnowing by embiotocids is characterized by premaxillary protrusions repeated cyclically with reduced oral gape. Protrusion is accompanied by depression of the hyoid apparatus and adduction of the opercula. Alternating expansion and contraction of the buccal and opercular cavities generate regular pressure waveforms that indicate bidirectional water flow during processing. Separation of food from debris by Embiotoca jacksoni occurs in three phases. The prey‐debris bolus is transported anteriorly and posteriorly within the oropharyngeal cavity and is then sheared by the pharyngeal jaws. Mechanical processing is complemented by the rinsing action of water currents during hydraulic prey transport.The feeding apparatus of Embiotoca jacksoni is functionally versatile, although not obviously specialized relative to that of nonwinnowing surfperches. Protrusion of the premaxillae and depression of the hyoid apparatus are critical to both prey capture and subsequent prey processing. The pharyngeal jaws exhibit kinematic patterns during separation of food from debris distinct from those observed during mastication of uncontaminated prey. This behavioral flexibility facilitates resource partitioning and the coexistence of E. jacksoni in sympatric embiotocid assemblages.
Fractal analysis of sagittal suture morphology
Authors: Hartwig Walter Carl 
Published: February 2005

AbstractQuantifying shape is a broad problem in the morphological sciences. Most techniques for numerically describing shape abstract the shape into the most logical ideal Euclidean dimension. The fractional, or fractal, dimension is a simple computation that expresses shape in real, rather than ideal, space. The structured walk technique developed for the fractal analysis of rugged boundaries is applied here to the contour of the human sagittal suture in order to discriminate the separate morphological patterns of interfingering and interlocking. These attributes contribute differentially to the suture's “complexity,” a concept often used in biomechanical hypotheses. Previous techniques for estimating sutural complexity do not isolate small‐scale from large‐scale morphological patterns. Results indicate that despite the visual appearance of great variation, human sagittal sutures are remarkably consistent in the degree of complexity expressed separately by large‐scale interfingering lateral excursions and small‐scale interlocking ruggedness. There is no significant correlation between the absolute or bregma‐lambda chord length of the human sagittal suture and its degree of complexity as determined by the structured walk technique.
Internal reproductive system in adult males of the genus Camponotus (Hymenoptera: Formicidae: Formicinae)
Authors: Wheeler Diana E. , Krutzsch Philip H. 
Published: February 2005

AbstractDescriptions are provided of the histology and ultrastructure of the male internal reproductive tracts from three species of Camponotus, representing three subgenera. This study is the first to provide ultrastructural information on the testes (including spermatogenesis and spermiogenesis), seminal vesicles, and accessory glands in ants. Testes contain about ten follicles each, and each follicle is capable of producing hundreds of cysts in which spermatozoa develop. Structural evidence of meiosis in late pupal testes includes cytoplasmic bridges between spermatocytes, centriole elimination, and fusion of mitochondria. Developing spermatids are in close contact with cyst cells in the region of the acrosome. Mature spermatozoa are similar in ultrastructure to those described previously for two other subfamilies of ants (Myrmicinae and Dolichoderinae). The ultrastructure of the seminal vesicle suggests that it is not merely a passive organ for sperm storage. Large numbers of both mitochondria and membranous whorls suggest a pH‐regulating and/or hormonal function. The accessory gland is made up of secretory cells that contain a diversity of secretory granules. SDS‐PAGE reveals several proteins found in the accessory glands but absent in the adjacent genitalia. Preliminary analyses indicate that carbohydrate is an important component of accessory gland secretions.
Figures of Eberth in the amphibian larval epidermis
Authors: Fox Harold 
Published: February 2005

AbstractFigures of Eberth are prominent extensive filamentous structures in the basal epidermal cells of larval amphibians. They are compared and contrasted qualitatively and quantitatively in a number of species of the three groups of living amphibians.Fully developed Figures consist of massive skeins of tonofilaments oriented in three dimensions and hinged on hemidesmosomes within the cell. The overall appearance of the Figures is similar in anurans, urodeles and Ichthyophis among the apodans. However, in terms of size and number per unit length of the proximal cell margin, the hemidesmosomes and the thickness or their emergent skeins in anurans and Ichthyophis differ significantly from those parameters in urodeles, a feature that is presumably independent of cell size. Figures are poorly developed or missing in embryos of Typhlonectes, which has no larval stage in its life history.These ubiquitous skeletogenous structures in the aquatic larval amphibians, among other things, could be protective of underlying delicate tissues and act as a stabilizer in bodily movement during swimming. They could also serve as a reserve of cytokeratin for use during later cellular division and sloughing.
Electron microscopic structure and innervation of the carotid baroreceptor region in the rock hyrax (Procavia capensis)
Authors: Kimani James Kirumbi 
Published: February 2005

AbstractSemi‐thin plastic sections reveal that the carotid baroreceptor region in the rock hyrax comprising the origin of the internal carotid artery has a preponderantly elastic structure and a thick tunica adventitia. In contrast, the common carotid artery has a musculoelastic structure, whereas the cranial segment of the internal carotid artery (immediately distal to the baroreceptor areas) shows the features of a muscular artery. Electron microscopy discloses the presence of sensory nerve endings within the parts of the tunica adventitia adjoining the preponderantly elastic zone of the internal carotid artery. These nerve endings are characterized by varicose regions containing a large quantity of mitochondria. Bundles of collagen fibers in the tunica adventitia form convolutions or whorls around the nerve terminals and often terminate on the surface of the elastic fibers or into the basement membranes of the neuronal profiles. The large content of elastic tissue in the tunica media of the baroreceptor region may render the vessel wall highly distensible to intraluminal pressure changes. This, in turn, would facilitate the transmission of the stimulus intensity to the sensory nerve terminals located in the tunica adventitia. It is suggested that the stretching of elastic fibers may form the main mechanical event leading to the distortion of the associated nerve terminals. However, a change in the geometrical configuration of the bundles of collagen under the influence of the elastic fibers may provide a better insight into the mechanisms of distortion of the baroreceptors related to and/or in contact with collagen fibers. © 1992 Wiley‐Liss, Inc.
Ultrastructural and cytochemical aspects of oogenesis in Castrada viridis (platyhelminthes, rhabdocoela)
Authors: Falleni Alessandra , Lucchesi Paolo 
Published: February 2005

AbstractThe heterocellular female gonad of the typhloplanoid Castrada viridis consists of a single germarium and two rows of vitellaria. The germarium, composed of a germinative zone and a growth zone, is surrounded externally by a layer of accessory cells the function of which is hypothesized in this study. The main feature of oocyte differentiation is the synthesis of small electron‐dense inclusions produced by the rough endoplasmic reticulum (R.E.R.) and Golgi complex. The electron‐dense content of the egg inclusions reacts positively to the cytochemical test used to detect polyphenols and is only partially extracted following incubation in protease. The genesis, composition, and peripheral location of egg inclusions in mature oocytes suggest that they could represent residual eggshell granules. The presumed function of eggshell granules is discussed and their fine morphology is compared with that observed in other neoophoran Platyhelminthes. © 1992 Wiley‐Liss, Inc.
Effects of sex steroid implants on reproductive tissues of female garter snakes (Thamnophis sirtalis)
Authors: Whittier Joan M. 
Published: February 2005

AbstractFemale Thamnophis sirtalis were administered intraperitoneal implants of either estradiol 17β (E2), testosterone (T), 5α‐dihydrotestosterone (DHT), or empty silastic capsules for 3 weeks. Plasma levels of E2 and T, measured by specific radioimmunoassay, were significantly elevated in E2 and T‐implanted females when compared to controls. T‐implanted females did not have elevated circulating E2 levels, suggesting that E2 in the plasma normally is not derived from peripheral conversion of T to E2. Implantation of DHT did not significantly change circulating levels of E2, T, or DHT. All three sex steroid—treated groups of animals had increased oviductal mass compared to controls, while hepatic mass of only E2‐treated animals was significantly greater. None of the steroid treatments influenced ovarian mass. Oviductal epithelial cell height and area were greater in the three steroid‐treated groups. Testosterone increased myometrial area while DHT drastically altered oviductal morphology. Hepatic cell area and number increased significantly in E2‐treated females. However, a small increase in both hepatic cell area and number was noted in T‐ and DHT‐treated females as well. These results suggest that androgen in both an aromatizable and non‐aromatizable form can affect the oviduct of females but that the liver primarily responds to estrogenic steroids. © 1992 Wiley‐Liss, Inc.
Sutural complexity in artificially deformed human (Homo sapiens) crania
Authors: Anton Susan C. , Jaslow Carolyn R. , Swartz Sharon M. 
Published: February 2005

AbstractThe pattern of complexity of cranial sutures is highly variable both among and within species. Intentional cranial vault deformation in human populations provides a controlled natural experiment by which we were able to quantify aspects of sutural complexity and examine the relationship between sutural patterns and mechanical loading. Measures of sutural complexity (interdigitation, number, and size of sutural bones) were quantified from digitized tracings of 13 sutures and compared among three groups of crania (n = 70) from pre‐European contact Peru. These groups represent sample populations deformed in (1) anteroposterior (AP) and (2) circumferential (C) directions and (3) an undeformed population. Intergroup comparisons show few differences in degree or asymmetry of sutural interdigitation. In the few comparisons which show differences, the C group is always more interdigitated than the other two while the AP group has more sutural bones. The sutures surrounding the temporal bone (sphenotemporal, occipitotemporal, and temporoparietal) most frequently show significant differences among groups. These differences are related to the more extreme binding of C type deformation and are consistent with hypothesized increases in tension at coronally oriented sutures in this group. The larger number of sutural bones in the AP group is consistent with the general broadening of the cranium in this group and with experimental evidence indicating the development of ossicles in areas of tension. We suggest that so few changes in sutural complexity occurred either because the magnitude of the growth vectors, unlike their direction, is not substantially altered or because mechanisms other than sutural growth modification are responsible for producing the altered vault shapes. In addition, the presence of fontanelles in the infant skulls during binding and the static nature of the binding may have contributed to the similarity in complexity among groups. © 1992 Wiley‐Liss, Inc.
Functional implications of neural canal anatomy in recent and fossil marine carnivores
Authors: Giffin Emily B. 
Published: February 2005

AbstractA statistical and functional relationship between neural canal anatomy and locomotor mode is demonstrated in living marine mammals of the Order Carnivora. This relationship is interpreted to be the result of differential innervation and territory of musculature involved in generating the six locomotor patterns analyzed. This osteological reflection of a behavioral trait allows prediction of locomotor pattern in extinct genera of closely related taxa. The robust data allow such predictions even when a considerable number of presacral vertebrae are missing in the fossil specimens. In some cases, these predictions conflict with interpretations based solely on limb osteology. © 1992 Wiley‐Liss, Inc.
Structure of recent and fossil mysid statoliths (Crustacea, Mysidacea)
Authors: Wittmann K. J. , Schlacher T. A. , Ariani A. P. 
Published: February 2005

AbstractStatoliths of 61 Recent species representing all subfamilies of Mysidae were studied with special emphasis on internal structure. In addition 5 samples of fossil statoliths from Miocene deposits were examined. Species of Boreomysinae and Rhopalophthalminae show simple roughly spherical organic statoliths, with setae originating from the sensory cushion and anchored in the statolith with distal branches extending shortly below the surface. All other subfamilies possess mineralized statoliths of greater structural complexity, with differentiation in core and mantle, where each part may consist of up to three layers. Habitus is hemispherical to discoidal. External gross structures are dorsal tegmen, ventral fundus, and the ambitus forming the outer toroidal to semi‐toroidal circumference. Setae penetrate the mantle through mineralic canals and insert on the surface of the core. As suggested by congeneric species of Schistomysis, there is no principal structural difference between statoliths mineralized with fluorite compared to vaterite. However, vaterite statoliths tend to be more often of moruloid appearance and are exceptional by showing a central conical hole (the hilum) or a central cavity in certain forms. These structures are typical of fossil calcite statoliths. In vaterite and fluorite statoliths, the mantle shows radially arranged (= spherulitic) crystal aggregates. Such arrangements are badly preserved in fossil calcite statoliths. In large extant statoliths, concentric structures, mainly in the form of superficial striation and/or concentric microstrata, are visible in coexistence with radial aggregates. Stratification is possibly due to stratified deposition of the nonmineralized gland product, while the spherulitic structure is indicative of subsequent radial growth of crystal aggregates. The structure of accessory fluorite statoliths in the statocyst of Mesopodopsis slabberi leads to the hypothesis that mantle material is formed by secretions of the caudal statocyst gland. After demineralization of fluorite, vaterite and calcite statoliths, an organic template remains showing most essential morphological features of the statolith. From this we conclude that the structure of the statolith is (almost) entirely matrix mediated. © 1993 Wiley‐Liss, Inc.
Variations in the distribution of motor end‐plates in the avian pectoralis
Authors: Gaunt Abbot S. , Gans Carl 
Published: February 2005

AbstractMost avian muscles consist of serially arranged, overlapping fibers that do not extend the length of the muscle. This condition appears to be plesiomorphic with respect to diapsid reptiles. The presence of this serialfibered architecture is evidenced by bands of stained motor end‐plates (meps) perpendicular to the columns of fibers and dividing each column into a series of “segments.” The avian pectoralis was chosen for a study of variation in the distribution of meps within a single muscle. We report the interspecific variation for 158 specimens in 63 species. We also use additional specimens to examine intraspecific variation.Setting aside hummingbirds, which have an unique and clearly derived condition, the number of mep bands along a column of fibers near the shoulder falls within a remarkably small range. The number of segments is not obviously related to phylogenetic relatedness or to any characteristic of flight or ecology and is only slightly related to size. The largest specimens do average more segments per column, but there are no trends among small to medium‐sized species, suggesting that there is an upper limit to fiber length. However, the shape of the sternum and pattern of connective tissue in the pectoralis alleviate the need for additional fibers in many large birds. These findings suggest that the architecture of the avian pectoralis is subject to some as yet unexplained selection that stabilizes the number of myofibers and/or motor neurons. The findings provide few clues as to whether the significant factors are phylogenetic, functional, ontogenetic, or some combination of these. © 1993 Wiley‐Liss, Inc.
An ultrastructural study of the dorsal lingual epithelium of the crab‐eating frog, Rana cancrivora
Authors: Iwasaki Shin‐Ichi , Wanichanon Chaitip 
Published: February 2005

AbstractThe amphibian tongue contains two types of papilla which are believed to function in gustation and in the secretion of salivary fluid. Scanning electron microscopy reveals that columnar, filiform papillae are compactly distributed over nearly the entire dorsal surface of the tongue of the frog, Rana cancrivora, and fungiform papillae are scattered among the filiform papillae. Microridges and microvilli are distributed on the epithelial cell surface of the extensive area of the filiform papillae. Light microscopy shows that the apex of each filiform papilla is composed of stratified columnar and/or cuboidal epithelium and its base is composed of simple columnar epithelium. Transmission electron microscopy reveals that most of the epithelium of the filiform papillae is composed of cells that contain numerous round electron‐dense granules 1–3 μm in diameter. Cellular interdigitation is well developed between adjacent cells. On the free‐surface of epithelial cells, microridges or microvilli are frequently seen. Between these granular cells, a small number of ciliated cells, mitochondria‐rich cells and electron‐lucent cells are inserted. In some cases, electron‐dense granules are present in the ciliated cells. At higher magnification, the electron‐dense granules appear to be covered with patterns of spots and tubules. Overall, the morphology and ultrastructure of the lingual epithelium of the three species of Rana that have been studied are quite similar, but they can be easily distinguished from those of Bufo japonicus. Therefore, it appears that lingual morphology is phylogenetically constrained among members of the predominantly freshwater genus Rana to produce uniformity of papillary structure and this morphology persists in Rana cancrivora despite the distinct saline environment in which it lives. © 1993 Wiley‐Liss, Inc.
Land crabs with smooth lungs: Grapsidae, Gecarcinidae, and Sundathelphusidae ultrastructure and vasculature
Authors: Farrelly Caroline A. , Greenaway Peter 
Published: February 2005

AbstractThe highly terrestrial grapsids and gecarcinids and the amphibious sundathelphusids all have large, expanded branchial chambers. The lining of the branchial chambers is smooth and well vascularized, and it functions as a lung. The respiratory membrane and the cuticle lining the lung are extremely thin (200–350 nm). The blood vessels within the lung are formed from connective tissue cells supported by collagen fibres and lined by a basal lamina. The major vessels in the lung are embedded deep in the branchiostegite and lie just beneath the thick outer carapace. These vessels branch towards the respiratory membrane, where they eventually lose their connective tissue coverings to form thin, flattened lacunae directly below the respiratory epithelium. The lacunae (exchange sites) are bordered by specialized connective tissue cells, which either bear microvilli on their apical surface (fimbriated cells) or are very smooth. The respiratory circulation in the lung is very complex, with two portal systems present between the afferent and efferent systems, producing a total of three lacunal exchange beds. Portal systems increase the surface area available for gas exchange. The major distributing vessel in the lung is the branchiostegal vein, which runs along the inner margin of the branchiostegite. The main venous supplies come anteriorly from the infraorbital and ventral sinuses and posteriorly from the procardial sinus. The main collecting vessel is the pulmonary vein, which arises anteriorly and which runs around the ventral perimeter of the branchiostegite before emptying into the pericardial sinus. © 1993 Wiley‐Liss, Inc.
Follicular dynamics and germinal bed activity during the annual ovarian cycle of the lizard, Calotes versicolor
Authors: Shanbhag Bhagyashri A. , Prasad B. S. Krishna 
Published: February 2005

AbstractChanges in size frequency distribution of extrastromal follicles, atretric follicles (AF), and the number of oogonia, oocytes, and primordial follicles in the ovaries are studied in Calotes versicolor during its annual reproductive cycle. Extrastromal follicles were graded into stages I to VI based on their diemeter. Stage I (0.5–0.75 mm) follicles are found throughout the year. The recruitment of stage II (0.76–1 mm) and stage III (1.10–2 mm) follicles occurs during December and March, respectively. Follicles of stage I–III are found in greater number in May. Stage IV vitellogenic follicles (2.10–3 mm) are recruited in April. Advanced vitellogenic follicles (stage VI) are formed between May and August. From April to August, the ovaries of lizards contain vitellogenic follicles of stages IV or V or VI suggesting that once a set of follicles enters vitellogenic phase there is no recruitment of another set of vitellogenic follicles from previtellogenic follicles until the former ovulates. The presence of vitellogenic follicles and at least two sets of CL in July‐August suggest that C. versicolor may oviposit at least three clutches of eggs per season. The clutch size in this lizard varies from a maximum 24 eggs in May to a minimum of 13 eggs in September. The previtellogenic AF are found throughout the year. Atresia is more prevalent in stage III suggesting that these follicles are more prone to become atretic. Interestingly, atresia of vitellogenic follicles occurs rarely. Each ovary in C. versicolor has two germinal beds. The germinal beds contain a greater number of oogonia (536–696), primary oocytes (40–71), and primordial follicles (32–55) during prebreeding and early breeding phases of the ovarian cycle. © 1993 Wiley‐Liss, Inc.