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Journal of Morphology

Carola Becker, Gerhard Scholtz
Female reproductive systems are important characters for understanding the evolution of Brachyura and resolving its phylogenetic relationships. We herein investigate a podotreme brachyuran reproductive system comprehensively for the first time studying spermathecae and gonopores of Homoloidea with histological methods, micro-computer tomography and scanning electron microscopy. Our results show that spermathecal apertures are species-specific and their shape corresponds closely to that of male copulatory organs...
October 17, 2016: Journal of Morphology
Hannah E Westlake, Louise R Page
Staurozoan cnidarians display an unusual combination of polyp and medusa characteristics and their morphology may be informative about the evolutionary origin of medusae. We studied neuromuscular morphology of two staurozoans, Haliclystus 'sanjuanensis' and Manania handi, using whole mount immunohistochemistry with antibodies against FMRFamide and α-tubulin to label neurons and phalloidin to label muscles. All muscles appeared to lack striations. Longitudinal interradial muscles are probable homologues of stalk muscles in scyphopolyps, but in adult staurozoans they are elaborated to inwardly flex marginal lobes of the calyx during prey capture; these muscles are pennate in M...
October 2, 2016: Journal of Morphology
Katherine T Nesbit, Robert D Roer
Observations of cuticular structures mineralized with silica within the Crustacea have been limited to the opal teeth of copepods, mandibles of amphipods, and recently the teeth of the gastric mill in the blue crab Callinectes sapidus. Copepod teeth are deposited during premolt, with sequential elaboration of organic materials followed by secretion of silica into the tooth mold. The timing of mineralization is in stark contrast to that of the general integument of crustaceans in which calcification is completely restricted to the postmolt period...
September 20, 2016: Journal of Morphology
Hiroto Ichishima
A cribriform plate, a perpendicular plate, and two lateral masses are major components of the ethmoid bone of mammals. Notwithstanding the noticeable bone, virtually sitting in the center of the skull, extensive modifications of the skull of modern cetaceans, especially odontocetes (toothed whales), and the lack of clarity as to what characteristics delimit each element of the ethmoid has made the problem of the nature of the cetacean ethmoid more complicated and elusive than in other, less modified mammals...
September 19, 2016: Journal of Morphology
Xu Wang, Yingping Xie, Yanfeng Zhang, Weimin Liu
Porphyrophora (Hemiptera: Coccomorpha: Margarodidae) is a genus of soil-inhabiting scale insects. The antennal sensilla and their innervation in the first-instar nymphs of Porphyrophora sophorae were studied using light microscopy and scanning and transmission electron microscopy to understand the function of these sensilla and determine the sensillar innervation feature on these small antennae. The results show that the six-segmented antennae of these nymphs have 20-23 sensilla which can be morphologically classified into seven types, for example, one Böhm's bristle (Bb), one campaniform sensillum (Ca), one Johnston's organ (Jo), 13-16 aporous sensilla trichodea (St), two coeloconic sensilla (Co), one straight multiporous peg (Mp1), and one curvy multiporous peg (Mp2)...
September 19, 2016: Journal of Morphology
Aina-Cathrine Øvergård, Lars A Hamre, Ewa Harasimczuk, Sussie Dalvin, Frank Nilsen, Sindre Grotmol
Exocrine glands of blood-feeding parasitic copepods are believed to be important in host immune response modulation and inhibition of host blood coagulation, but also in the production of substances for integument lubrication and antifouling. In this study, we aimed to characterize the distribution of different types of salmon louse (Lepeophtheirus salmonis) exocrine glands and their site of secretion. The developmental appearance of each gland type was mapped and genes specifically expressed by glands were identified...
September 19, 2016: Journal of Morphology
Eric G Ekdale
Living mysticetes (baleen whales) and odontocetes (toothed whales) differ significantly in auditory function in that toothed whales are sensitive to high-frequency and ultrasonic sound vibrations and mysticetes to low-frequency and infrasonic noises. Our knowledge of the evolution and phylogeny of cetaceans, and mysticetes in particular, is at a point at which we can explore morphological and physiological changes within the baleen whale inner ear. Traditional comparative anatomy and landmark-based 3D-geometric morphometric analyses were performed to investigate the anatomical diversity of the inner ears of extinct and extant mysticetes in comparison with other cetaceans...
September 14, 2016: Journal of Morphology
Lisa Schnetz, Cathrin Pfaff, Jürgen Kriwet
The dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. Also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. High-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order Lamniformes, which were considered not to be phylogenetically informative, the histotype and the number of teeth per tooth file...
September 1, 2016: Journal of Morphology
Alois Lametschwandtner, Christine Radner, Bernd Minnich
Microvascular anatomy and histomorphology of larval and adult spleens of the Clawed Toad, Xenopus laevis were studied by light microscopy of paraplast embedded serial tissue sections and scanning electron microscopy (SEM) of vascular corrosion casts (VCCs). Histology showed i) that white and red pulp are present at the onset of metamorphic climax (stage 57) and ii) that splenic vessels penetrated deeply into the splenic parenchyma at the height of metamorphic climax (stage 64). Scanning electron microscopy of VCCs demonstrated gross arterial supply and venous drainage, splenic microvascular patterns as well as the structure of the interstitial (extravasal) spaces representing the "open circulation routes...
August 31, 2016: Journal of Morphology
Aaron M Olsen, Mark W Westneat
Many musculoskeletal systems, including the skulls of birds, fishes, and some lizards consist of interconnected chains of mobile skeletal elements, analogous to linkage mechanisms used in engineering. Biomechanical studies have applied linkage models to a diversity of musculoskeletal systems, with previous applications primarily focusing on two-dimensional linkage geometries, bilaterally symmetrical pairs of planar linkages, or single four-bar linkages. Here, we present new, three-dimensional (3D), parallel linkage models of the skulls of birds and fishes and use these models (available as free kinematic simulation software), to investigate structure-function relationships in these systems...
August 31, 2016: Journal of Morphology
Steve M Reilly, Stephane J Montuelle, Andre Schmidt, Cornelia Krause, Emily Naylor, Michael E Jorgensen, Richard L Essner
Although the anuran pelvis is thought to be adapted for jumping, the function of the iliosacral joint has seen little direct study. Previous work has contrasted the basal "lateral-bender" pelvis from the "rod-like" pelvis of crown taxa hypothesized to function as a sagittal hinge to align the trunk with take-off forces. We compared iliosacral movements and pelvic motor patterns during jumping in the two pelvic types. Pelvic muscle activity patterns, iliosacral anteroposterior (AP) movements and sagittal bending of the pelvis during the take-off and landing phases were quantified in lateral bender taxa Ascaphus (Leiopelmatidae) and Rhinella (Bufonidae) and the rod-like Lithobates (Ranidae)...
August 31, 2016: Journal of Morphology
Rachel Claire Aland, Edward Gosden, Adrian J Bradley
The vomeronasal system consists of a peripheral organ and the connected central neuronal networks. The central connections are sexually dimorphic in rodents, and in some species, parameters of the vomeronasal organ (VNO) vary with sex, hormonal exposure, body size and seasonality. The VNO of the dasyurid marsupial mouse, Antechinus subtropicus is presumed to be functional. The unusual life history (male semelparity) is marked by distinct seasonality with differences in hormonal environments both between males and females, and in males at different time points...
November 2016: Journal of Morphology
Masato Nakano, Tomoyuki Saino
White's tree frog (Litoria caerulea) has large, adhesive toe pads that are among the softest of all known biological structures. To explore the morphological basis for the physical properties of the toe pads, the internal microstructure of the toe pads in L. caerulea was examined using both light and transmission electron microscopy. Three design elements that are distinct from other areas of skin were observed. First, the keratinocytes comprising the adhesive surface of the toe pad all contained keratin filament bundles (tonofibrils) exhibiting structural anisotropy...
November 2016: Journal of Morphology
Aurélie Pinton, Soizic Le Fur, Olga Otero
In the fossil record, the quantification of continuous morphological variation has become a central issue when dealing with species identification and speciation. In this context, fossil taxa with living representatives hold great promise, because of the potential to characterise patterns of intraspecific morphological variation in extant species prior to any interpretation in the fossil record. The vast majority of catfish families fulfil this prerequisite, as most of them are represented by extant genera...
November 2016: Journal of Morphology
Courtney L Goulet, Harrison J Smith, Takashi Maie
When animals grow, the functional demands that they experience often change as a consequence of their increasing body size. In this study, we examined the feeding biomechanics in esocid species that represent different size classes (small, Esox americanus; intermediate, Esox niger; large, Esox lucius), and how their bite forces and associated functional variables change as they grow. In order to evaluate bite performance through ontogeny, we dissected and measured dimensions of the feeding apparatus and the adductor mandibulae muscle complex with its segmentum facialis subdivisions such as the ricto-malaris, stegalis and endoricto-malaris across a wide range of body sizes...
November 2016: Journal of Morphology
Sarah Hayer, Stephanie Köhnk, Susann Boretius, Dirk Brandis
The reproductive system of the female Ethusa mascarone was studied with a combination of histological and MRI-techniques. The study reveals a completely new type of eubrachyuran seminal receptacle. This receptacle consists of two largely separate chambers that engage with each other in a manner similar to shaking hands. One chamber facing the medial axis is lined by cuticle while the second chamber consists of a thick holocrine epithelium. Both chambers are connected by two openings of a unique structure. First, the glandular chamber opens ventro-laterally to the cuticle chamber via a laterally flattened connective duct that is lined by a highly folded cuticle...
November 2016: Journal of Morphology
Jamie A MacLaren, Sandra Nauwelaerts
Forelimb morphology is an indicator for terrestrial locomotor ecology. The limb morphology of the enigmatic tapir (Perissodactyla: Tapirus) has often been compared to that of basal perissodactyls, despite the lack of quantitative studies comparing forelimb variation in modern tapirs. Here, we present a quantitative assessment of tapir upper forelimb osteology using three-dimensional geometric morphometrics to test whether the four modern tapir species are monomorphic in their forelimb skeleton. The shape of the upper forelimb bones across four species (T...
November 2016: Journal of Morphology
Thomas Frase, Stefan Richter
Using immunohistochemical labeling against acetylated a-tubulin and serotonin in combination with confocal laser scanning microscopy and 3D-reconstruction, we investigated the temporary freshwater pond inhabitant Branchinella sp. (Crustacea: Branchiopoda: Anostraca) for the first time to provide detailed data on the development of the anostracan nervous system. Protocerebral sense organs such as the nauplius eye and frontal filament organs are present as early as the hatching stage L0. In the postnaupliar region, two terminal pioneer neurons grow from posterior to anterior to connect the mandibular neuromeres...
November 2016: Journal of Morphology
Mateus R Beguelini, Cintia C I Puga, Eliana Morielle-Versute, Sebastião R Taboga
In eutherian mammals, the male reproductive accessory glands (RAGs) comprise the prostate, bulbourethral glands, ampullary glands, and the seminal vesicles. Their composition, anatomy and function vary widely between species. This study aimed to characterize histologically and compare the RAGs of bats. The RAGs of Noctilio albiventris (Noctilionidae) and Rhynchonycteris naso (Emballonuridae) were studied using anatomical and histological methods, and were reconstructed three dimensionally. The RAGs of N. albiventris and R...
November 2016: Journal of Morphology
Günter Vogt
Crustaceans are a morphologically, physiologically, and ecologically highly diverse animal group and correspondingly diverse are their reproductive characteristics. They have evolved structural specialties with respect to penis construction, sperm form, sperm storage, fertilization, and brood care. Unique in the animal kingdom are safety lines that safeguard hatching and first molting. Further curiosities are dwarf males in parasitic and sessile crustaceans and bacteria-induced feminization and gigantism of crustacean hosts...
November 2016: Journal of Morphology
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