Abstract:
:The evolution of viviparity alters the physical relationship between mothers and offspring and the prevalence of viviparity among squamate reptiles presents an opportunity to uncover patterns in the evolution of placental structure. Understanding the breadth of this diversity is limited because studies of placental structure and function have emphasized a limited number of lineages. We studied placental ontogeny using light microscopy for an embryological series of the Mexican gerrhonotine lizard, Mesaspis viridiflava. This species develops an elaborate yolk sac placenta, an omphaloplacenta, which receives vascular support arising in a structure known only from other gerrhonotine lizards. A prominent feature of the omphaloplacenta is a zone of uterine and embryonic epithelial cell hyperplasia located at the upper shoulder of the yolk mass, often extending above the yolk mass. The omphaloplacenta covers more than one-half of the surface area of maternal-embryonic contact. The chorioallantoic placenta has a more restricted distribution because the allantois remains in the embryonic hemisphere of the egg throughout development and lies internal to the vascular support for the omphaloplacenta in areas where they overlap. The structural profile of the chorioallantoic placenta indicates a potential for respiratory exchange and/or hemotrophic nutritive transport, while that of the omphaloplacenta suggests that nutritive transfer is primarily via histotrophy. An eggshell is present in the earliest embryonic stages examined but regresses relatively early in development. Placental specializations of this species are consistent with a pattern of matrotrophic embryonic nutrition and have evolved in a unique lineage specific developmental pattern.
journal_name
J Morpholjournal_title
Journal of morphologyauthors
Stewart JR,Mendez de la Cruz FRdoi
10.1002/jmor.20912subject
Has Abstractpub_date
2019-01-01 00:00:00pages
35-49issue
1eissn
0362-2525issn
1097-4687journal_volume
280pub_type
杂志文章abstract::This study describes the male reproductive cycle of Sibynomorphus mikanii from southeastern Brazil considering macroscopic and microscopic variables. Spermatogenesis occurs during spring-summer (September-December) and spermiogenesis or maturation occurs in summer (December-February). The length and width of the kidne...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.20099
更新日期:2013-02-01 00:00:00
abstract::The mammary gland is a common site of neoplasms in the female cat. All the malignant tumors metastasize to a lesser or a greater extent through the lymphatic system. However, the anatomical knowledge of this system is not sufficiently well known in cats to develop a reasoned model for the extirpation of these glands i...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.10403
更新日期:2006-03-01 00:00:00
abstract::The octavolateralis area of actinopterygian fishes can be subdivided into a dorsal lateralis area composed of first-order lateral line nuclei, and a ventral octavus area composed of nuclei receiving first-order input from the eighth nerve. Three patterns of organization of the lateralis area are recognized in the pres...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051710205
更新日期:1982-02-01 00:00:00
abstract::The silk production systems of several specimens representing at least three species of the mygalomorph genus Euagrus were examined by dissection and by a variety of absorption and fluorescent histochemical techniques. The intrageneric variation is primarily restricted to gland number, with larger numbers of glands in...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051860205
更新日期:1985-11-01 00:00:00
abstract::The oval olfactory rosette of the carp Labeo rohita belongs to Burne's ('09) rosette column one or to Bateson's (1889) rosette type three. The total olfactory area of the fish is greater than its total retinal area; however, it has been classified with Teichmann's ('54) group of eye-nose fishes. Each olfactory chamber...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051400107
更新日期:1973-05-01 00:00:00
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journal_title:Journal of morphology
pub_type: 杂志文章,评审
doi:10.1002/(SICI)1097-4687(199609)229:3<325::AID-JMOR
更新日期:1996-09-01 00:00:00
abstract::The allometric relations of diameter and length of humerus, ulna, femur, and tibia of 108 specimens, from 63 different breeds of dogs and 12 specimens of wolves, were calculated by means of model II of regression or major axis method. Only for the tibia were the values of wolves included in the cluster formed for dog ...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051900107
更新日期:1986-10-01 00:00:00
abstract::In the Mexican axolotl (Ambystoma mexicanum), the pronephros begins to form at the four-somite stage. It is initially continuous with the posterior-lateral region of somite 2 and the lateral margin of somites 3 and 4. By the seven-somite stage, the pronephros has become compacted, and the cells are now morphologically...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051850207
更新日期:1985-08-01 00:00:00
abstract::Only species belonging to the bryozoan subtaxon Phylactolaemata possess an epistome. To test whether there is a specific coelomic cavity inside the epistome, Fredericella sultana, Plumatella emarginata, and Lophopus crystallinus were studied on the ultrastructural level. In F. sultana and P. emarginata, the epistome c...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.10691
更新日期:2009-03-01 00:00:00
abstract::Scanning electron microscopy reveals that the flat tongue of Platemys pallidipectoris has shallow grooves and no lingual papillae. The surface of the tongue is covered with dome-shaped bulges, each corresponding to a single cell. Short microvilli are distributed over the cell surface. Light microscopy shows a stratifi...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052260303
更新日期:1995-12-01 00:00:00
abstract::Homology is resemblance caused by a continuity of information. In biology it is a unified developmental phenomenon. Homologies among and within individuals intergrade in several ways, so historical homology cannot be separated sharply from repetitive homology. Nevertheless, the consequences of historical and repetitiv...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051730307
更新日期:1982-09-01 00:00:00
abstract::The sharpness and thus information content of the retinal image in the eye depends on the optical quality of the lens and its accurate positioning in the eye. Multifocal lenses create well-focused color images and are present in the eyes of all vertebrate groups studied to date (mammals, reptiles including birds, amph...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.10849
更新日期:2010-08-01 00:00:00
abstract::Prey capture in Agama stellio was recorded by high-speed video in combination with the electrical activity of both jaw and hyolingual muscles. Quantification of kinematics and muscle activity patterns facilitated their correlation during kinematic phases. Changes in angular velocity of the gape let the strike be subdi...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052240306
更新日期:1995-06-01 00:00:00
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journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.10769
更新日期:2009-12-01 00:00:00
abstract::The dorsal vessel (DV) in the abdomen of the blood-feeding insect Rhodnius prolixus was divided functionally into two regions, the heart, into which haemolymph entered the DV through four pairs of ostia located in abdominal segment VII, and the aorta, along which the haemolymph was propelled from abdominal segment VI ...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052040103
更新日期:1990-04-01 00:00:00
abstract::Morphological features of the goldfish caudal neurosecretory system were investigated by means of immunohistochemical localization of urotensins I and II (UI and UII) and electron microscopic examination of the caudal neurosecretory neurons, the urophysis, and the synaptic neuropil. The aim of the work is to provide a...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/(SICI)1097-4687(199801)235:1<59::AID-JMOR5
更新日期:1998-01-01 00:00:00
abstract::The Eurasian lynx (Lynx lynx) is a medium-sized felid, with a tendency to hunt for prey larger than itself. We studied the lynx hindlimb musculoskeletal anatomy in order to determine possible anatomical adaptations to hunting large prey. In our previous work, we had found characters of both large and small felids in t...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.21328
更新日期:2021-01-25 00:00:00
abstract::A large sample of embryological material of the North American paddlefish Polyodon spathula (Acipenseriformes: Polyodontidae) confirms that early development in Polyodon is very similar to that reported for the sister group of Polyodontidae, the sturgeons (Acipenseridae). Polyodon illustrates many basic aspects of aci...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052130106
更新日期:1992-07-01 00:00:00
abstract::We investigated growth-related and sex-related morphological changes in the skulls of 144 North Pacific common minke whales Balaenoptera acutorostrata. Measurement was conducted at 39 points on the skull and mandible to extract individual allometric equations relating the length and zygomatic width of the skull. The r...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.20288
更新日期:2014-10-01 00:00:00
abstract::Two types of sperm are produced in the silkworm, Bombyx mori. Nucleate eupyrene sperm is an ordinary sperm that contributes to fertilization, while anucleate apyrene sperm is considered to play important roles in assisting eupyrene sperm. At the very late stage of spermatogenesis, a phenomenon called "peristaltic sque...
journal_title:Journal of morphology
pub_type: 杂志文章
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更新日期:2004-01-01 00:00:00
abstract::Bristle positions in two rows of bristles on the basitarsus of the second leg of the fruitfly Drosophila melanogaster were analyzed in order to determine the accuracy of bristle placement within these rows. Within each row the positions of the two terminal bristles were found to be approximately equally variable, and ...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051780203
更新日期:1983-11-01 00:00:00
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journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051970303
更新日期:1988-09-01 00:00:00
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journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052060111
更新日期:1990-10-01 00:00:00
abstract::A reduction in free ribosomes and increases in rough endoplasmic reticulum and Golgi complexes in follicle cells during oogenesis suggest their involvement in supplying precursor material for synthesis of the vitelline and chorionic membranes of the ichneumonid parasitoid Campoletis sonorensis. The inner region of the...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051740207
更新日期:1982-11-01 00:00:00
abstract::The vascular system of the digits of the tokay is more complex than has hitherto been suspected and has a configuration which suggests it is intimately involved in the process of adhesion. Distinction can be made between lamellae (expanded scales beneath the proximal portion of the digit) and scansors (elaborations of...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051690305
更新日期:1981-09-01 00:00:00
abstract::The study of the arterial arches of Bipes, the only amphisbaenian with forelimbs, resolves the problem of the interpretation of the structure of the arterial arches in other forms of this group of squamate reptiles. In Bipes, as in turtles, the subclavian and common carotid arteries originate from a brachiocephalic tr...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1051840202
更新日期:1985-05-01 00:00:00
abstract::The morphometry, histochemistry, and biomechanical relationships of rectus capitis muscles were examined in adult cats. This family of muscles contained six members on the dorsal, ventral, and lateral aspects of the upper cervical vertebral column. Three dorsal muscles (rectus capitis posterior major, medius, and mino...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052160107
更新日期:1993-04-01 00:00:00
abstract::Sabellid and sabellariid polychaetes are regarded as sister groups in a number of recent phylogenetic analyses. This is based mainly on a shared specific arrangement of chaetae referred to as chaetal inversion. Remarkably, the uncini have a notopodial position in the abdomen, whereas capillary chaetae occur in the neu...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.10537
更新日期:2008-01-01 00:00:00
abstract::According to the current opinion, lymph-heart striated muscle represents a specialized type of skeletal muscles in frogs. Here, we studied muscle fibers in mechanically damaged lymph hearts during the first postoperative week using electron-microscopic autoradiography. We present evidence that both, the satellite cell...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.20476
更新日期:2015-12-01 00:00:00
abstract::The female reproductive system of Sphaerodema rusticum consists of a pair of ovaries, two lateral oviducts, a median common oviduct, and a median spermatheca. Accessory glands are absent. Each ovary has five free ovarioles branching from the oviduct. Each ovariole consists of a terminal filament, germarium, vitellariu...
journal_title:Journal of morphology
pub_type: 杂志文章
doi:10.1002/jmor.1052050207
更新日期:1990-08-01 00:00:00