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Journal of Morphology

Mariana L Adami, Francisco Brusa, Jorge R Ronderos, Cristina Damborenea
Previous studies demonstrated complex architecture of the muscular system of Macrostomum species, especially in the rostrum area and the pharynx. However, little is known about the differences in muscular pattern between species of the genus. This study examines and compares the muscular systems of specimens belonging to three freshwater Macrostomum species (M. quiritium, M. tuba and M. velastylum), labeled with phalloidin-rhodamine and studied by confocal microscopy. Our results agree with the previous descriptions, confirming that the muscular patterns for the body wall, rostrum area, pharynx and caudal region differ among species...
November 29, 2016: Journal of Morphology
K J Soda, D E Slice, G J P Naylor
Over the past few decades, geometric morphometric methods have become increasingly popular and powerful tools to describe morphological data while over the same period artificial neural networks have had a similar rise in the classification of specimens to preconceived groups. However, there has been little research into how well these two systems operate together, particularly in comparison to preexisting techniques. In this study, geometric morphometric data and multilayer perceptrons, a style of artificial neural network, were used to classify shark teeth from the genus Carcharhinus to species...
November 28, 2016: Journal of Morphology
Taketeru Tomita, Kei Miyamoto, Akira Kawaguchi, Minoru Toda, Shin-Ichiro Oka, Ryo Nozu, Keiichi Sato
Unlike most viviparous vertebrates, lamniform sharks develop functional teeth during early gestation. This feature is considered to be related to their unique reproductive mode where the embryo grows to a large size via feeding on nutritive eggs in utero. However, the developmental process of embryonic teeth is largely uninvestigated. We conducted X-ray microcomputed tomography to observe the dentitions of early-, mid-, and full-term embryos of the white shark Carcharodon carcharias (Lamniformes, Lamnidae)...
November 27, 2016: Journal of Morphology
Julia A Schultz, Ulrich Zeller, Zhe-Xi Luo
The monophyletic clade Monotremata branches early from the rest of the mammalian crown group in the Jurassic and members of this clade retain many ancestral mammalian traits. Thus, accurate and detailed anatomical descriptions of this group can offer unique insight into the early evolutionary history of Mammalia. In this study, we examine the inner ear anatomy of two extant monotremes, Ornithorhynchus anatinus and Tachyglossus aculeatus, with the primary goals of elucidating the ancestral mammalian ear morphology and resolving inconsistencies found within previous descriptive literature...
November 27, 2016: Journal of Morphology
Sophie Regnault, John R Hutchinson, Marc E H Jones
Sesamoids bones are small intra-tendinous (or ligamentous) ossifications found near joints and are often variable between individuals. Related bones, lunulae, are found within the menisci of certain joints. Several studies have described sesamoids and lunulae in lizards and their close relatives (Squamata) as potentially useful characters in phylogenetic analysis, but their status in the extant outgroup to Squamata, tuatara (Sphenodon), remains unclear. Sphenodon is the only living rhynchocephalian, but museum specimens are valuable and difficult to replace...
November 24, 2016: Journal of Morphology
Ting-Yu Huang, Chun-Che Chang, Nai-Chen Cheng, Mu-Hui Wang, Ling-Ling Chiou, Kuang-Lun Lee, Hsuan-Shu Lee
Axolotls (Ambystoma mexicanum) may heal their skin wounds scar-free in both paedomorphs and metamorphs. In previous studies on small punch skin wounds, rapid re-epithelialisation was noted in these two axolotl morphs. However, large wound size in mammals may affect wound healing. In this study, large circumferential full thickness excision wounds on the hind limbs were created on juvenile paedomorphic and metamorphic axolotls. The results showed re-epithelialisation was more quickly initiated in paedomorphs than in metamorphs after wounding...
November 17, 2016: Journal of Morphology
Daniela L Del Castillo, Mariana Viglino, David A Flores, Humberto L Cappozzo
Comparisons of skull shape between closely related species can provide information on the role that phylogeny and function play in cranial evolution. We used 3D-anatomical landmarks in order to study the skull ontogeny of two closely related species, Lagenorhynchus obscurus and Lagenorhynchus australis, with a total sample of 52 skulls. We found shared trends between species, such as the relative compression of the neurocranium and the enlargement of the rostrum during ontogeny. However, these are common mammalian features, associated with prenatal brain development and sensory capsules...
November 17, 2016: Journal of Morphology
Nicola S Heckeberg
Antlers are unique appendages. They are shed and rebuilt at intervals, and are synapomorphic for all living Cervidae (except for the Chinese water deer, Hydropotes inermis, in which they have presumably been lost). The antlerogenic process is controlled by a complex interaction of fluctuating levels of several hormones, most importantly testosterone. The oldest antler remains are recorded from the early Miocene; these have been interpreted as non-deciduous appendages because of supposed permanent skin coverage and the lack of a burr (a well-developed osseous protuberance around the base of the antler, which is always present in extant cervids)...
November 17, 2016: Journal of Morphology
Rafael Magno Costa Melo, Débora Diniz Gomes, Davidson Peruci Moreira, Maysa Regina Gomes, Nilo Bazzoli, Elizete Rizzo
The success of fishes in different environments is related with the variation of reproductive strategies developed by the systematic group, which is reflected in the morphology of the reproductive system and can have ecological and evolutionary implications. This study comparatively analyzed the morphological characteristics of the male and female reproductive systems of ostariophysan fish species from the upper Das Velhas River in the São Francisco River basin, Brazil. In order to accomplish this, 393 specimens belonging to seven fish species were sampled between April 2010 and June 2015 for histological, ultrastructural, histochemical, and morphometric analyses...
November 8, 2016: Journal of Morphology
Victor R Townsend, Maynard H Schaus, Tatyana Zvonareva, Jeffrey J Illinik, John T Evans
Previous studies of leg injuries in harvestmen have focused on the fitness consequences for individuals that use autospasy (voluntary detachment of the leg) as a secondary defense mechanism. Leg damage among non-autotomizing species of laniatorean harvestmen has not been investigated. Under laboratory conditions, we damaged femur IV of Cynorta marginalis and observed with scanning electron microscopy (SEM) the changes in these wounds over ten days. We also used SEM to examine leg damage from individuals of three species of cosmetid harvestmen that were collected in the field...
November 8, 2016: Journal of Morphology
Monika Żelazowska, Dorota Fopp-Bayat
Previtellogenic and vitellogenic oocytes in ovarian follicles from cultured Siberian sturgeon Acipenser baerii were examined. In previtellogenic oocytes, granular and homogeneous zones in the cytoplasm (the ooplasm) are distinguished. Material of nuclear origin, rough endoplasmic reticulum, Golgi complexes, complexes of mitochondria with cement and round bodies are numerous in the granular ooplasm. In vitellogenic oocytes, the ooplasm comprises three zones: perinuclear area, endoplasm and periplasm. The endoplasm contains yolk platelets, lipid droplets, and aggregations of mitochondria and granules immersed in amorphous material...
November 8, 2016: Journal of Morphology
Stephan Henne, Frank Friedrich, Jörg U Hammel, Andy Sombke, Andreas Schmidt-Rhaesa
The Nematomorpha (horsehair worms) and Nematoda (round worms) are sister taxa (together Nematoida) and closely related to Scalidophora (Priapulida, Kinorhyncha, Loricifera). To date, all species were assumed to possess a specific brain type, i.e., the "cycloneuralian" brain that forms a ring-shaped neuropil around the pharynx and is composed of anteriorly and posteriorly located somata. However, descriptions of the nematomorph nervous system are rare and somewhat variable, calling in to question the validity of the cycloneuralian condition...
November 2, 2016: Journal of Morphology
L Alibardi, F Michieli, L Dalla Valle
During tail regeneration in lizards, the stratified regenerating epidermis progressively gives rise to neogenic scales that form a new epidermal generation. Initially, a soft, un-scaled, pliable, and extensible epidermis is formed that is progressively replaced by a resistant but non-extensible scaled epidermis. This suggests that the initial corneous proteins are later replaced with harder corneous proteins. Using PCR and immunocytochemistry, the present study shows an upregulation in the synthesis of low-cysteine type I and II alpha-keratins and of corneous beta-proteins with a medium cysteine content and a low content in glycine (formerly termed beta-keratins) produced at the beginning of epidermal regeneration...
November 2, 2016: Journal of Morphology
Pedro Pereira Rizzato, Maria Elina Bichuette
The laterosensory system is a mechanosensory modality involved in many aspects of fish biology and behavior. Laterosensory perception may be crucial for individual survival, especially in habitats where other sensory modalities are generally useless, such as the permanently aphotic subterranean environment. In the present study, we describe the laterosensory canal system of epigean and subterranean species of the genus Ituglanis (Siluriformes: Trichomycteridae). With seven independent colonizations of the subterranean environment in a limited geographical range coupled with a high diversity of epigean forms, the genus is an excellent model for the study of morphological specialization to hypogean life...
October 21, 2016: 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...
December 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...
December 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)...
December 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...
December 2016: Journal of Morphology
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