bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical analysis of newly synthesized and accumulated sulfated glycosaminoglycans during musculogenesis in the embryonic chick leg
Authors: Young Henry E. , Carrino David A. , Caplan Arnold I. 
Published: February 2005

AbstractThe leg musculature from 11, 14, and 17 day chick embryos was analyzed histochemically to investigate the temporal and spatial distribution of various types of sulfated glycosaminoglycans present during skeletal muscle development. Types of glycans were identified by selective degradation with specific glycosidases and nitrous acid coupled with Alcian blue staining procedures for sulfated polyanions and with [35S]sulfate autoradiography. On day 11, radiolabeled chondroitin sulfate glycosaminoglycans are localized extracellularly in both the myogenic and connective tissue cell populations. By day 17, incorporation of [35S]sulfate into chondroitin sulfate is substantially reduced, although Alcian blue‐stained chondroitin sulfate molecules are still detectable. With increasing age and developmental state of the tissues, radiolabeled and stained dermatan sulfate and heparan sulfate progressively increase in relative quantity compared to chondroitin sulfate both in muscle and in associated connective tissue elements. These changes in glycosaminoglycans correlate well with similar changes previously determined biochemically and further document the alterations in extracellular matrix components during embryonic skeletal myogenesis.
Number and distribution of hair cells in the utricular macula of some avian species
Authors: Jørgensen J. Mørup 
Published: February 2005

AbstractThe utricular macula was examined in 20 bird species belonging to 13 families. Two types of hair cells, a bouton‐innervated and a calyceal hair cell, were found. The calyceal hair cells are found situated in two zones that follow the anterior and lateral borders of the utricular macula in all except two species. In the rhea and mute swan, only one zone was found, corresponding to the inner zone of the other species. The majority of calyceal hair cells are present in the anterior and lateroposterior part of the inner zone. They are often gathered in a common calyx. More hair cells are found within the same calyx in birds than described in previously examined reptile and mammalian species. In nine specimens of four species belonging to four different families, the calyceal hair cells constitute between 7 and 12% of the total number of hair cells, which varies from about 20,000 to 40,000.
Parthenogenetic reproduction in the neotropical unisexual lizard,Gymnophthalmus underwoodi(Reptilia: Teiidae)
Authors: Hardy Laurence M. , Cole Charles J. , Townsend Carol R. 
Published: February 2005

AbstractAll adult specimens known forGymnophthalmus underwoodiare females, and their mode of reproduction has been a mystery. In order to rule out the possibility of a bisexual mode of reproduction by means of mating with undiscovered males, hermaphroditism, or sex reversal during ontogeny, we examined hundreds of serial histological sections of complete reproductive tracts from juveniles and adults representing two generations of a lineage raised in captivity. In addition, comparative dissections were performed on other individuals and other species, and reproduction to the F5generation was documented in laboratory colonies ofG. underwoodiestablished from Trinidad and Surinam stocks. A lineage of three successive generations was produced entirely by individuals that were maintained in isolation from the moment of hatching.All specimens ofG. underwoodiproved to be female, with reproductive anatomy identical to that of females of closely related, bisexual species ofGymnophthalmus: G. pleeiandG. speciosus. Thus,G. underwoodiis an all‐female species that reproduces by means of strict parthenogenesis, in the absence of sperm.As in the macroteiids of the genusCnemidophorusstudied previously,Gymnophthalmushas functional mesonephric kidneys throughout life.G. underwoodiranks among the smallest amniotes, adults weighing about 1.2 gm and having a body length of 36–43 mm. Data from the laboratory colonies indicate the following: clutch size, 1–4 (X= 2); mean egg size about 9.4 × 6.5 mm (weight, 0.23 gm); development time, up to 61 days or more; hatchling body length, 16–19 mm (X= 18); hatchling tail length, 18–25 mm (X= 22); hatchling weight, 0.09–0.14 gm (X= 0.115); reproduction continuous year round with individuals able to produce successive clutches in less than a month but quiescent periods following reproductive sessions; maturity attainable seven mo after hatching; longevity at least 4 yr and 5 mo; and a dramatic decline occurred in egg viability in successive generations in the laboratory.
The nervous system in the praesoma of Echinorhynchus salmonis (Acanthocephala: Echinorhynchidae)
Authors: Gee Randall J. 
Published: February 2005

AbstractBased on light microscopic observations, nerve pathways are described for the first time in the praesoma of a species of the Echinorhynchidae. The pathways are described for 18 nerves, 8 paired and 2 single, which originate from the cerebral ganglion and a post‐ganglionic cell and terminate in the body wall musculature and the proboscis. The location of two commissures formed by these nerves is also described.
Sexually dimorphic laryngeal morphology in Rana pipiens
Authors: McClelland Blinda E. , Wilczynski Walter 
Published: February 2005

AbstractThe sexually dimorphic vocal characteristics of Rana pipiens release calls suggest that there may be differences in the anatomical components of the larynx. The volumes of the arytenoid cartilage, surrounding muscle masses, vocal cords, supporting bronchial process, and the release‐call amplitudes of six males and five females were measured in same‐sized animals and sexual differences assessed. No qualitative differences in laryngeal morphology were observed, but all features measured except vocal cords were significantly larger in males. The implications of an increased laryngeal size are discussed in relation to differences previously observed in the vocalizations of this and other species and in relation to prior suggestions regarding the developmental basis of anuran sexual dimorphisms.
Ontogeny of the skeleton of Spea bombifrons (anura: Pelobatidae)
Authors: Wiens John J. 
Published: February 2005

AbstractThe developing skeleton of a pelobatid frog, Spea bombifrons, is described based on a series of 81 cleared‐and‐stained tadpoles and juveniles. Most limb and limb‐girdle elements commence ossification premetamorphically, along with the parasphenoid, frontoparietals, exoccipitals, and vertebral column, during Gosner Stage 36. The chondrocranium undergoes dramatic restructuring at the beginning of metamorphosis (ca. Stage 40); and the nasal cartilages, prootics, premaxillae, nasals, maxillae, septomaxillae, and ischium appear. Near the end of metamorphosis (ca. Stage 44), the branchial arches are resorbed, the hyoid plate and quadrate form, and the angulosplenials, vomers, squamosals, dentaries, and pterygoids ossify. After metamorphosis (Stage 46), the laryngeal cartilages, sternum, omosternum, and plectral apparatus chondrify; and the carpals, tarsals, sphenethmoid, posteromedial hyoid processes, mentomeckelian bones, quadrates, columellae, and opercula ossify. The development of the fused sacrococcygeal articulation in S. bombifrons is described and compared to the more widespread bicondylar articulation. The presumed palatine bone and transverse processes of the coccyx are discussed, as are several seemingly paedomorphic skeletal features of Spea. Comparison with the sequence and timing of ossification in other anurans reveals that ossification of the skull and vertebral column occurs later in S. bombifrons than in other anurans; nonetheless, many aspects of the ossification sequence seem to be shared by a surprisingly wide range of anuran taxa.
Neuromast morphology and lateral line trunk canal ontogeny in two species of cichlids: An SEM study
Authors: Webb Jacqueline F. 
Published: February 2005

AbstractA study of neuromast ontogeny and lateral line canal formation in Oreochromis aureus and Cichlasoma nigrofasciatum reveals the existence of two classes of neuromasts: those that arise just before hatching (presumptive canal neuromasts, dorsal superficial neuromasts, gap neuromasts, and caudal fin neuromasts) and pairs of neuromasts that arise on each lateral line scale lateral to each canal segment at the same time as canal formation. In the anterior trunk canal segment, each presumptive canal neuromast is accompanied by a dorsoventrally oriented superficial neuromast forming an orthogonal neuromast pair. It is suggested that each of these dorsoventrally oriented superficial neuromasts is homologous to the transverse superficial neuromast row described by Münz (Zoomorphology 93:73–86, '79) in other cichlids. It is further suggested that the longitudinal lines described by Münz (Zoomorphology 93:73–86, '79) are derived from the pair of superficial neuromasts that arise during canal formation. Distinct changes in neuromast topography are documented. Neuromast formation, scale formation, and lateral line canal formation are three distinct and sequential processes. The distribution of neuromasts is correlated with myomere configuration; there is always one presumptive canal neuromast on each myomere. A single scale forms beneath each presumptive canal neuromast. Canal segment formation is initiated with the enclosure of each presumptive canal neuromast by an epithelial bridge which later ossifies. The distinction of these three processes raises questions as to the causal relationships among them.
Structure and development of iridescent butterfly scales: Lattices and laminae
Authors: Ghiradella H. 
Published: February 2005

AbstractIridescent butterfly scales are structurally colored, relying upon the interaction of light with detailed architecture to produce their color. In some iridescent scales, the reflective elements are contained within the body of the scale and come in two basic forms, lattices that produce diffraction colors (analogous to those produced by opal), and stacks of laminae that produce thin‐film interference colors (analogous to those produced by soap or oil films). Both structures are remarkably complex and precise, yet each is only part of the total edifice built by the cell that makes the scale.To understand better how a cell can produce lattices or thin‐film laminae, I studied the development of iridescent scales from two lycaenid butterflies. The presence of diffraction and thin‐film scales in the same family (and in some cases on the same individual) suggests that the two types must be developmentally related; yet these results yield no clear explanation as to how. The diffraction lattice appears to be shaped within the boundaries of the scale cell by means of a convoluted series of membranes in which the smooth endoplasmic reticulum plays an important part. The thin‐film interference laminae appear to result from the condensation of a network of filaments and tubes secreted outside the boundaries of the cell. This paper outlines the developmental histories of both types of scale and discusses the developmental implications of the mechanisms by which they form.
Comparison of the muscle mechanics of the forelimb of three climbers
Authors: Stalheim‐Smith Ann 
Published: February 2005

AbstractThe climbing behavior, muscle mechanics, and functional properties of selected forelimb muscles were examined to ascertain how three distantly related mammals may be adapted for climbing. To determine if features of the fox squirrel (Stalheim‐Smith: J. Morphol.180:55–68, apos;84) are general or unique features for a climber, two distantly related climbers, the raccoon (Procyon lotor) and the opossum (Didelphis virginiana), were studied. Muscle mechanics varied: the elbow flexors of the fox squirrel produced significantly more torque per unit mass than did the corresponding muscles of the opossum except at 80°, but not more than the corresponding muscles of the raccoon. On the other hand, there were no statistically significant differences in torque per unit mass among the elbow extensors of the three climbers. Both elbow flexors and elbow extensor had faster contraction times and were more fatigable in the fox squirrel than in the opossum or in the raccoon. The data suggest that the musculoskeletal characteristics of the forelimbs of climbers vary according to behavioral, and possibly phylogenetic, differences.
Feeding mechanism of Epibulus insidiator (Labridae; Teleostei): Evolution of a novel functional system
Authors: Westneat Mark W. , Wainwright Peter C. 
Published: February 2005

AbstractThe feeding mechanism of Epibulus insidiator is unique among fishes, exhibiting the highest degree of jaw protrusion ever described (65% of head length). The functional morphology of the jaw mechanism in Epibulus is analyzed as a case study in the evolution of novel functional systems. The feeding mechanism appears to be driven by unspecialized muscle activity patterns and input forces, that combine with drastically changed bone and ligament morphology to produce extreme jaw protrusion. The primary derived osteological features are the form of the quadrate, interopercle, and elongate premaxilla and lower jaw. Epibulus has a unique vomero‐interopercular ligament and enlarged interoperculo‐mandibular and premaxilla‐maxilla ligaments. The structures of the opercle, maxilla, and much of the neurocranium retain a primitive labrid condition. Many cranial muscles in Epibulus also retain a primitive structural condition, including the levator operculi, expaxialis, sternohyoideus, and adductor mandibulae. The generalized perciform suction feeding pattern of simultaneous peak cranial elevation, gape, and jaw protrusion followed by hyoid depression is retained in Epibulus. Electromyography and high‐speed cinematography indicate that patterns of muscle activity during feeding and the kinematic movements of opercular rotation and cranial elevation produce a primitive pattern of force and motion input. Extreme jaw protrusion is produced from this primitive input pattern by several derived kinematic patterns of modified bones and ligaments. The interopercle, quadrate, and maxilla rotate through angles of about 100 degrees, pushing the lower jaw into a protruded position. Analysis of primitive and derived characters at multiple levels of structural and functional organization allows conclusions about the level of design at which change has occurred to produce functional novelties.
Postcranial skeleton of the marine catfish arius tenuispinis (osteichthyes: Siluriformes, Ariidae)
Authors: Lakshmi K. , Rao K. Srinivasa 
Published: February 2005

AbstractThe axial skeleton and the skeletal supports of median and paired fins of Arius tenuispinis, a marine catfish, are described. Particular attention is given to the description of the complex vertebra, the Weberian ossicles, and the articulations between the fin spines and their respective radials and girdle elements.
Functional morphology of the “tongue‐bite” in the osteoglossomorph fish Notopterus
Authors: Sanford Christopher P. , Lauder George V. 
Published: February 2005

AbstractOsteoglossomorph fishes are characterized by having three sets of jaws: a mandibular jaw apparatus (MJA) anteriorly, a pharyngeal jaw apparatus (PJA) posteriorly, and a tongue‐bite apparatus (TBA) associated with basihyal and parasphenoid teeth. The TBA is a novel complex feature of the head that characterizes osteoglossomorph fishes and provides a case study in the origin of novel functions and roles in the vertebrate musculoskeletal system.The function of the tongue‐bite in the osteoglossomorph fish Notopterus was characterized by using high‐speed cinematography and electromyography. The tongue‐bite is used during intraoral prey processing to shred and disable prey. Two distinct uses of the TBA were defined on the basis of kinematic and electromyographic profiles: raking and open‐mouth chewing. During raking behavior, the prey is held fixed in the MJA, the neurocranium is elevated, and the pectoral girdle is retracted. The adductor mandibulae, hypaxialis, epaxialis, and posterior intermandibularis muscles are all highly active, but only very low activity is observed in the sternohyoideus muscle. During open‐mouth chewing behavior, the prey is located within the oral cavity, posterior pectoral girdle rotation is less than during raking, and the levator operculi muscle shows relatively high activity.We propose that a shearing action of the basihyal (moved anteroposteriorly by the posterior intermandibularis and hypaxial muscles) with respect to the neurocranium (elevated by epaxial muscles) is the critical aspect of the tongue‐bite in Notopterus. The body muscles (epaxials and hypaxials) provide the main power for the tongue‐bite. We hypothesize that lack of sternohyoideus activity during intraoral prey processing, posterior pectoral girdle rotation, and a long‐fibered posterior intermandibularis muscle are novel structures associated with the tongue‐bite apparatus within osteoglossomorph fishes.
Changes in the fine structure of the endocrine dorsal body cells of Helisoma duryi (mollusca) induced by mating
Authors: Khan Hamid R. , Ashton Mary Lou , Saleuddin A. S. M. 
Published: February 2005

AbstractThe morphology and the organization of the endocrine dorsal bodies (DB) of non‐reproducing virgin and castrated, and reproducing mated Helisoma duryi have been examined using serial sectioning. The DB cells occur in two masses on the mid‐dorsal side of the cerebral commissure, each of which has a cortical zone containing the cell bodies and a medulla where cell processes terminate. The cell bodies measure 10–15 μm in diameter, and are arranged in lobules of 6–12 cells. The complex cell processes are winding and terminate at various distances from their cell bodies in both reproducing and non‐reproducing snails. Few 70–90‐nm membrane‐bound granules are found in the cell bodies and many are seen in the cell processes, which seem to penetrate the perineurium of the cerebral ganglia and make close contacts with neurosecretory cells. In reproducing snails the DB cells display a significantly larger amount of plasma membrane sproutings in the form of loops and circles compared to that in reproductively inactive virgin or castrated snails. Images of thin‐sections and freeze‐fracture replicas of these membranes suggest that they are gap junctions, which join the DB cells with each other. It is likely that gap junction‐mediated cell to cell communication is involved in the activation of the DB cells for their role(s) in reproduction.
Embryonic and neonatal development of the vomeronasal and olfactory systems in garter snakes (Thamnophis spp.)
Authors: Holtzman David A. , Halpern Mimi 
Published: February 2005

AbstractNewborn, unfed garter snakes (Thamnophis spp.) respond preferentially to aqueous extracts of natural prey items, and these responses are mediated by the vomeronasal system (VNS). Since the VNS, and possibly the olfactory system (OS), are functional at birth, we examined the ontogeny of VNS and OS structures in four embryonic stages and two postnatal ages in garter snakes. The results of this study show (1) significant changes in thickness of the receptor epithelia for both systems; (2) temporal differences in the innervation of the telencephalon for each system; and (3) concurrent development of primary and secondary projection sites in both systems. Possible interactions between different cell populations and their significance for morphogenesis are discussed.
Ontogeny of the limb skeleton in Alligator mississippiensis: Developmental invariance and change in the evolution of archosaur limbs
Authors: Müller Gerd B. , Alberch Pere 
Published: February 2005

AbstractCrocodilians and birds are the extant representatives of a monophyletic taxon known as archosaurs. Their limbs are highly derived in terms of reduction in number of skeletal elements in both the carpus and the tarsus. It is necessary to have a detailed description of crocodilian limb ontogeny to address the evolutionary issue dealing with the origin and organization of the avian limb. In this paper, we present an analysis of the early development of the crocodilian limb skeleton. Contrasting with earlier observations, we redefine the number and composition of carpal, tarsal, and phalangeal elements. This ontogenetic information is then used to introduce a revision of the homologies of the skeletal elements in the crocodilian limb. Some invariances are pointed out in the developmental organization of tetrapod limbs and this evidence serves to readdress several issues concerning the evolution of the avian limb. We present further embryological data in support of the hypothesis that digits 2–3–4 are the components of the wing skeleton in birds. In general, our comparative survey indicates that the elements that appear late in ontogeny are the ones lost in phylogeny. By comparing turtle (primitive) limb development with crocodilian and bird development, we propose a hypothesis in which the derived skeletal patterns found in crocodilians and birds have originated by a heterochronic process of paedomorphosis.
Extrusion of the residual body in spermatids of Ancylostoma caninum (nematoda, strongyloidea)
Authors: Ugwunna Sydney C. 
Published: February 2005

AbstractTransmission electron microscopy reveals that the spermatocytes of the hookworm Ancylostoma caninum contain an abundance of Golgi complexes, ribosomes, specialized membranous organelles, and long strands of smooth endoplasmic reticulum. These organelles remain abundant until the early spermatid stage of sperm development, when they reach their maximum abundance and maturity and the production of new ones ceases. Golgi complexes, ribosomes, and excess SER, which are not functional after this stage, become segregated and confined to the posterior portion of the spermatid in a polar lobe. Later, the polar lobe together with excess cytoplasmic matrix is bound by a membrane and dissociated from the spermatid as a residual body. The spermatid is then devoid of Golgi complexes and ribosomes. Formation of residual bodies as sperm cells mature may be considered a type of cell excretion.
Golgi study of the anterior dorsal ventricular ridge in a lizard. I. neuronal typology in the adult
Authors: Díaz C. , Yanes C. , Medina L. , Trujillo C. M. , Monzón M. , Puelles L. 
Published: February 2005

AbstractUsing Golgi techniques we have studied neuronal cell types in the anterior dorsal ventricular ridge (ADVR) of the adult lizard Gallotia galloti. Multipolar, bitufted, and juxtaependymal neuronal forms were found. The multipolar and bitufted neurons are present in both the periventricular and central ADVR zones. Multipolar neurons can be subdivided into multipolar neurons with polygonal somata and four to six main dendritic trunks and multipolar neurons with pyramidal somata and three or more dendritic trunks. The former are the cells most frequently impregnated in the ADVR. In the population of bitufted neurons, we distinguish subtypes I, II, and III according to the number of dendritic trunks that emerge from the somata. Juxtaependymal neurons are restricted to a cell‐poor zone, adjacent to ependymal cells. Their dendrites either are orientated parallel to the ventricular surface or extend into the periventricular zone. The dendrites of ADVR neurons have pedunculated spines with knob‐like tips. However, such spines do not appear on the somata or on the primary dendritic trunks. The number of spines is scarce or moderate. The periventricular neuronal clusters contain two to five cells. The morphology of these neurons is mainly multipolar, but we also found some bitufted neurons.