Contribution to knowledge of the morphogenesis of the nasal apparatus of the fallow deer (Dama dama L.)

As in the red deer, in the fallow deer embryo we found a number of ancestral structures reminiscent of relationships in other mammals, such as paraseptal cartilages, a septum nasi with trabecular widening, a lamina transversalis ant., a cart. ectochoanalis, a capsule wall with a roof and a lateral wall formed of a clearly distinguishable cart. parietotectalis and cart. paranasalis, an ethmoturbinale I projecting a long way rostrally and additionally, in the fallow deer, cart. paraseptales posteriores. I regard the relationship of the cart. alaris inf. to the parietotectal cartilage (or "marginoturbinale") as relatively "primitive"; this may mean that the term "atrioturbinale" is also justified in mammals and that the relevant structure is homologous with the one known by the same name in birds. The specializations found during study of the morphogenesis of the nasal apparatus in the red deer (Slaby 1990b) are accentuated in the fallow deer. The chief ones are the specific rostral processes of the anlage of the nasal septum, which are a significant part of reinforcement of the nostril, the marked widening of the nasal capsule in a lateral direction (so that even the paranasal cartilages have a largely horizontal course), the striking ventrolateral bulge in the nasal capsule at the beginning of the olfactory region and the final resultant decrease in the height (i. e. flattening) of the capsule. This leads to reduction of the frontoturbinalia and their corresponding recesses, which - where they are developed - are oriented more horizontally. The structure of ethmoturbinale I, together with its insertion, is also simplified. As in the corresponding red deer embryo, the paranasal cartilage zone in the anterior part of the olfactory region is strikingly thickened; the frontoturbinalia do not, however, originate (in our stage) by the formation of cavities in the cartilage, but develop as simple processes. A crista semicircularis and foramen epiphaniale and also, as distinct from the red deer embryo, cart. paraseptales posteriores, are clearly discernible. In conclusion, it can therefore be claimed that the morphogenesis of specialized cervid features is accentuated in Dama more than in Cervus and that relationships in the fallow deer represent a further step in specialization, or - if we are speaking of the development of radiations - specialization here has progressed further.     

Contribution to knowledge of the morphogenesis of the nasal apparatus of the domestic sheep (Ovis aries L.)

The author studied the morphogenesis of the nasal apparatus in a sheep (Ovis aries L.) embryo with a length of 57 mm, at the optimum stage of development of the chondrocranium, as a part of his studies of development of the nasal apparatus in ungulates. The nasal apparatus is in general constructed according to the general scheme for mammals. Attention is drawn to the development of the superior alar cartilage, which is reminiscent of the situation in reptiles, to the strikingly developed atriturbinale auctorum (the author does not agree with this morphological designation, which is reserved for the vestibular turbinale in birds), to the well developed anterior paraseptal complex, to the extremely large maxilloturbinale and to the massive trunk of the ethmoturbinale I, which suppresses the corresponding recesses. The olfactory labyrinth is developed at three levels, the upper (rostral) level corresponding to the frontoturbinalia region, the middle to the ethmoturbinale I and the third (caudal) level to the region of the ethmoturbinalia II, III and IV (the recessus ethmoturbinalis). There is no foramen epiphaniale, no crista semicircularis and no crista Galli. A posterior paraseptal cartilage is present; in the author's opinion it is joined to the lamina orbitonasalis and not to the lamina transversalis post., since the latter is absent.     

Morphogenesis of the highly specialized nasal skull in the sperm whale (Physeter macrocephalus). I

Investigated the morphogenesis of the nasal structures of the chondrocranium and determatocranium in 15 embryos and foetuses of the sperm whale (Physeter macrocephalus). In the very early stages of the morphogenesis, the nasal capsule of Physeter shows a conspicuous similarity with that of all other odontocetes. In the following stages there are some important differences. Most peculiar is the occurrence of the cartilaginous tectum nasi with the cupulae nasi anteriores, elements which are reduced in all other odontocetes. This cartilaginous complex as a slender band projects obliquely forward from the upper edge of the anterior septal margin. It is free, i.e. not accompanied by membraneous bones. The complex represents the most important factor in the morphogenesis and growth of the characteristic big forehead in Physeter, which contains the spermaceti organ unique within the odontocetes. Other important differences concern the changes in the orientation of the nasal passages and the adjacent skeletal structures. Nevertheless, these differences have to be taken as specializations related to the development of the far-advanced spermaceti organ. As a whole, the embryonic nasal structures in Physeter belong to the same general type of nasal capsule which is common to all odontocetes. The results presented here suggest a close phylogenetic relationship between Physeter and the other Odontoceti.     

Morphogenesis of the cranium of Cavia porcellus L. II: Comparative part and literature

The development of the chondrocranium of Cavia porcellus is compared to those of other rodents. The tectum posterius of the investigated rodents is orientated vertically. This position is functionally caused by the attachment of the muscles of the neck and shoulder girdle. The paracondylar process is a typical feature of rodents although absent in Mesocricetus. Only in Cavia and Tatera, the connection between the lamina supraoccipitalis and the auditory capsule-the supraoccipitocapsular commissure-is missing. Youssef's (1966) generalization that the course of the notochord in rodents is of transbasal type cannot be confirmed. In Cavia, the auditory capsule is connected with the occipital region only by the exoccipitocapsular commissure. The connection between auditory capsule and basal plate is established by the alicochlear and the anterior basicapsular commissures. In comparison to other rodents, the number of commissures in Cavia is reduced. In rodents, there is always a subarcuate fossa which in later stages of development is filled out by the flocculus cerebelli. In contrary to Rajtova's (1972a) statement, Cavia shows a suprafacial commissure as all mammals do (Reinbach 1952). As the tegmen tympani is absent in Otomys and Erethizon, it is not a typical rodent feature. The carotid foramen is well developed in Cavia but the internal carotid artery obliterates until the 25 mm CRL-stage. In embryonic rodents, the ala temporalis may have a foramen ovale but not a foramen rotundum. During ontogeny rodents show the ala hypochiasmatica for the attachment of the straight muscles of the eyeball. In Cavia the ala hypochiasmatica develops independently and fuses with the postoptic root of the ala orbitalis in later stages. In myomorphs and sciumorphs, the orbitoparietal and orbitonasal commissures are present. Only in caviomorphs this part of the primary sidewall of the skull is uncomplete. Erethizon, however, shows an orbitonasal commissure whereas in Cavia both commissures are missing. In this respect the guinea-pig resembles the condition of primates. There is no interorbital septum in rodents. The nasal capsule of rodents contains 1 atrioturbinal, 1 maxilloturbinal, 1 nasoturbinal, and at least 3 ethmoturbinals. Due to the strong development of the alveoli of the incisors, the maxilloturbinale is flected in the caviomorphs. The epiphanial foramina are present. The lamina transversalis anterior is continuous with the nasal septum so that there is a complete zona anularis in rodents. The paraseptal cartilages are continuous with the lamina transversalis anterior but not with the lamina transversalis posterior.(ABSTRACT TRUNCATED AT 400 WORDS)     

Ontogeny of the palatoquadrate and adjacent lateral cranial wall of the endocranium in prehatching Alligator mississippiensis (Archosauria: Crocodylia)

The purpose of this article is to gain insight into the ossification sequence of the palatoquadrate and the adjacent lateral cranial wall of prehatching Alligator mississippiensis, a process about which there is almost no published information. Results were obtained by studying serial histological sections of the series of ontogenetic stages and enlarged wax-plate models of several stages. The cartilage of the palatoquadrate starts to ossify endochondrally in the quadrate portion of the pars pterygoquadrata palatoquadrati in Stage 6A. In this stage, a bone, called the lamina palatoquadrati anterior here, appears at and close to the anteromedial wall of the cartilaginous pterygoid portion of the pars pterygoquadrata. The lamina palatoquadrati anterior ossifies in membrane. Later in ontogeny, the lamina palatoquadrati anterior spreads into the cavum epiptericum and sheathes the posterior portion of the trigeminal ganglion laterally. The jaw adductor muscles insert at the outer surface of the lamina palatoquadrati anterior. The lamina palatoquadrati anterior is a new structure not previously recorded in crocodylians or any other Recent reptile. The topology, mode of ossification, and functional anatomy of the lamina palatoquadrati anterior correspond to those of the membranous ossification of the alisphenoid of marsupials. Another bone, called the lamina prootici anterior here, spreads in membrane from the anterolateral wall of the prootic portion of the otic capsule into the prootic fenestra, above the trigeminal ganglion. The lamina prootici anterior represents a structure not recorded previously in crocodylians. It contributes to the orbitotemporal braincase wall.     

Morphology of the nasal capsule of Heloderma suspectum with comments on the systematic position of helodermatids (Squamata: Helodermatidae)

A serially sectioned embryonic head of Heloderma suspectum formed the basis for a three-dimensional reconstruction of the cartilaginous nasal capsule and its membrane bones. Further, the soft parts of the nasal capsule were analysed microscopically. The embryonic nasal capsule is described and compared to the morphological conditions in other lizards, especially the varanids, which many recent authors believe to be their closest relatives.
The results support the close affinities between the helodermatids and the varanids. Both groups have a well developed recessus lateralis in a cartilaginous capsule, entered by the nasal concha. Further, in both groups a fragmentation of the cartilago paraseptalis occurs in a comparable location and form. Heloderma has no double lacrimal duct, in contrast to previous accounts, but the two canaliculi at the origin of the duct fuse noteworthy far ahead (in other squamates they fuse in front of the bulbus oculi). In the varanids the two branches of the lacrimal duct remain separate and open separately.
Some unique features of Heloderma are presented as well, above all the presence of a second concha.     

New ontogenetic evidence on the septomaxilla ofTamandua andCholoepus (Mammalia,Xenarthra), with a reevaluation of the homology of the mammalian septomaxilla

An intramembranous ossification at the anterior end of the cartilaginous nasal capsule is described for the first time in prenatal specimens of the anteaterTamandua and the slothCholoepus and redescribed in prenatal specimens of the armadillosDasypus andZaedyus. From comparisons of this bone with the septomaxilla of monotremes and various Mesozoic mammals, it is concluded that (1) the bone inTamandua andCholoepus is homologous with the central part (processus ascendens) of the bone inDasypus, Zaedyus, and other armadillos and (2) the xenarthran processus ascendens, in turn, is homologous with the central part of the septomaxilla of monotremes and various Mesozoic mammals. Therefore, the bone in question in xenarthrans is a true septomaxilla. It is further concluded that the armadillo septomaxilla has two neomorphic components: a lamina palatina beneath the cartilaginous nasal floor and a processus intrafenestralis extending rostrally into the nasal fossa.     

The histological structure and histochemistry of the mucosa of the nasal conchae in geese,Anser anser

We investigated the histological structure and histochemistry of the nasal conchae of geese and compared these structures with those of other avian species. The rostral, middle and caudal conchae were dissected from the nasal cavity of eight geese, fixed in Carnoy’s solution and embedded in paraffin. The entrance of the rostral concha was lined by keratinized stratified squamous epithelium, which toward the middle concha was replaced by modified keratinized squamous epithelium, the deep layer of which opened into tubular glandular structures containing secretory epithelium on crypt-like invaginations. The lamina propria of the rostral concha contained numerous Grandry’s and Herbst corpuscles, which are pressure-sensitive receptors peculiar to waterfowl. The lamina propria of the middle concha contained solitary lymphoid follicles and lymphocyte infiltrations. The cartilaginous component of the middle concha was highly convoluted and resembled a spiral of two and a half scrolls, which were lined by pseudostratified columnar epithelium. We observed that unlike mammals, this epithelium contained mostly intraepithelial alveolar glands rather than goblet cells. The caudal concha was similar to the middle concha, but less convoluted. It was lined by olfactory epithelium and its lamina propria contained serous Bowman’s glands as well as olfactory nerve fibers. Histochemical examination demonstrated that while none of the conchae contained sulfated mucins, except for the cartilage, the intraepithelial glands of the rostral and middle conchae contained mostly carboxylated acidic mucin and some neutral mucin, and were thus of the mixed type. The outermost scroll of the spiral of the middle concha contained some periodate-Schiff stained mucins. Of the glands of the mucosa of the middle concha, the deep tubuloalveolar glands in the convex parts of the scrolls contained primarily acidic mucins, while the shallow intraepithelial alveolar glands in the concave parts of the scrolls contained primarily neutral mucins. Our findings indicate that the rostral and caudal conchae primarily have a sensory function and the middle concha participates in mucosal defense.     

The prenatal morphogenesis of the lateral nasal wall in the rat (Mus rattus)

In the course of this investigation 24 fetuses of the Sprague-Dawley rats were used. Pregnant animals were sacrificed at 12, 14, 16, 18, and 20 days of gestation. The fetuses were removed and fixed in buffered formalin solution. The heads were dehydrated, embedded in paraffin, and the nasal cavities were sectioned serially. Light microscope observations were made on 10 to 15 μ thick sections stained with H and E, Mallory's trichrome stain, and Gomori's alkaline phosphatase stain. The 12 day old fetus possessed well developed olfactory depression with a thick epithelial covering. The olfactory fossa was still separated from the buccal cavity by a solid layer of young mesenchyme. In the 14 day old fetus the communication between the nasal and buccal cavities was established. The palatal shelves developed still vertically. All the turbinates and the nasal capsule were already differentiated. The glandular system was represented with the main and two to three accessory excretory ducts. During the sixteenth day of prenatal development, the sinus and the sinus related glands became for the first time evident. The ossification of the membranous parts of the lateral nasal wall was initiated. In the next two developing stages the maturation of the cartilage, the increasing ossification in the membrane, and the further differentiation of the glands were the major morphological changes in the formation of the lateral nasal wall.     

Emerging views on the distinct but related roles of the main and accessory olfactory systems in responsiveness to chemosensory signals in mice

In rodents, the nasal cavity contains two separate chemosensory epithelia, the main olfactory epithelium, located in the posterior dorsal aspect of the nasal cavity, and the vomeronasal/accessory olfactory epithelium, located in a capsule in the anterior aspect of the ventral floor of the nasal cavity. Both the main and accessory olfactory systems play a role in detection of biologically relevant odors. The accessory olfactory system has been implicated in response to pheromones, while the main olfactory system is thought to be a general molecular analyzer capable of detecting subtle differences in molecular structure of volatile odorants. However, the role of the two systems in detection of biologically relevant chemical signals appears to be partially overlapping. Thus, while it is clear that the accessory olfactory system is responsive to putative pheromones, the main olfactory system can also respond to some pheromones. Conversely, while the main olfactory system can mediate recognition of differences in genetic makeup by smell, the vomeronasal organ (VNO) also appears to participate in recognition of chemosensory differences between genetically distinct individuals. The most salient feature of our review of the literature is that there are no general rules that allow classification of the accessory olfactory system as a pheromone detector and the main olfactory system as a detector of general odorants. Instead, each behavior must be considered within a specific behavioral context to determine the role of these two chemosensory systems. In each case, one system or the other (or both) participates in a specific behavioral or hormonal response.     

Epithelial control of periotic mesenchyme chondrogenesis

Morphogenesis of the cartilaginous otic capsule is directed by interactions between the epithelial anlage of the membranous labyrinth (otocyst) and its associated periotic mesenchyme. Utilizing a developmental series of high-density (micromass) cultures of periotic mesenchyme to model capsule chondrogenesis, we have shown that the early influence of otic epithelium in cultures of 10.5- or 14-gestation day (gd) periotic mesenchyme results in initiation or suppression of chondrogenesis, respectively. Furthermore, we have shown that introduction of otic epithelium at two distinct times during in vitro development to cultures of 10.5-gd mesenchyme cells results first in an initiation and then in an inhibition of their chondrogenic response. These influences of epithelial tissue on chondrogenic differentiation by periotic mesenchyme are not tissue specific but are characterized by temporal selectivity. The ability of otic epithelium to influence chondrogenesis and the competence of the periotic mesenchyme to respond to its signals are dependent upon the developmental stage of both tissues. This study provides conclusive evidence that otic epithelium acts as a developmental "switch" during otic capsule morphogenesis, signaling first the turning on and then the turning off of chondrogenic programs in the responding cephalic mesenchyme.     

Morphology of the interorbital region of Saimiri sciureus

The skull of the platyrrhine primate Saimiri sciureus is distinguished by a large interorbital fenestra. Juvenile skulls still show a bony interorbital septum with some small gaps. A morphogenetic study was undertaken to better understand the structures of the interorbital region, which represents a linkage between the base of the braincase and the nasal skeleton. Already in early ontogenetic stages a reduction of the posterior portion of the nasal capsule and of the cartilaginous interorbital septum are observed, resulting in the formation of a primary interorbital fenestra. A bony interorbital septum is mainly formed in perinatal age stages by ossification of the presphenoid and by medial fusion of the frontals; the primary interorbital fenestra is retained as a small opening. It only occurs in late juvenile stages when the definitive interorbital fenestra develops by by secondary transformation of bone into a membrane of dense connective tissue; this process is most probably caused by mechanical friction of the very closely approximated eyes of both sides.     

Comparative landscape genetic analyses show a Belgian motorway to be a gene flow barrier for red deer (Cervus elaphus), but not wild boars (Sus scrofa)

While motorways are often assumed to influence the movement behaviour of large mammals, there are surprisingly few studies that show an influence of these linear structures on the genetic make-up of wild ungulate populations. Here, we analyse the spatial genetic structure of red deer (Cervus elaphus) and wild boars (Sus scrofa) along a stretch of motorway in the Walloon part of Belgium. Altogether, 876 red deer were genotyped at 13 microsatellite loci, and 325 wild boars at 14 loci. In the case of the red deer, different genetic clustering tools identified two genetic subpopulations whose borders matched the motorway well. Conversely, no genetic structure was identified in the case of the wild boar. Analysis of isolation-by-distance patterns of pairs of individuals on the same side and on different sides of the motorway also suggested that the road was a barrier to red deer, but not to wild boar movement. While telemetry studies seem to confirm that red deer are more affected by motorways than wild boar, the red deer sample size was also much larger than that of the wild boars. We therefore repeated the analysis of genetic structure in the red deer with randomly sub-sampled data sets of decreasing size. The power to detect the genetic structure using clustering methods decreased with decreasing sample size.     

Histologic studies of cartilaginous structures in the anterior region of the head of the sperm whale Physeter macrocephalus

Recently discovered cartilaginous structures in the forehead of the sperm whale (Behrmann and Klima 1985) were investigated histologically. The largest and most important of these structures is the nasal roof cartilage which can be derived from the tectum nasi, a part of the embryonic nasal capsule (Klima et al. 1986). In the investigated sperm whale fetuses, this structure consists of embryonic hyaline cartilage which is well suited for morphogenetic processes and fast growth. In the investigated adult sperm whale, the originally hyaline cartilage has been transformed into a special kind of elastic cartilage. The arrangement of cells, territories, and extracellular substance resembles hyaline cartilage. This component represents an adaptation to pressure load. The appearance and arrangement of elastic fibres resembles elastic cartilage. This component is an adaptation to distortion forces. Obviously, pressure and distortion are the strongest mechanical strains that the nasal roof cartilage is exposed. We see the function of this cartilage structure therein that, being a pressure-elastic skeletal support and following the left nasal meatus along its whole extension through the massive and soft forehead, it secures the only direct respiratory passage. Additionally, fibre bundles of transversely striated muscles are anchored in the perichondrium of the nasal roof cartilage. The function of this delicately interwoven muscle system is seen by us in the fine tuning of contraction and dilatation of the respiratory passage. Moreover, a possible function as a sound conducting cartilaginous structure serving the echolocation system is considered (c.f. Pilleri et al. 1983).     

A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.     

The fine structure of the female reproductive tract of adult Loa loa

Weber P. 1987. The fine structure of the female reproductive tract of adult Loa loa. International Journal for Parasitology17: 927–934. The wall of the female reproductive tract of Loa loa was studied by electron microscopy. The wall is composed of a monolayered epithelium covered by a basal lamina. The epithelium of the ovary has a moderately developed basal labyrinth, abundant organelles, and a few secretory granules. In the oviduct, the basal lamina intrudes septa-like into the epithelium. Abundant myofilaments are attached to it. Microvilli cover the luminal cell border. The seminal receptacle contains few muscle cells in its basal lamina. It shows a highly developed spongy zone at its luminal surface. The uterine epithelium contains glycogen deposits and lipid droplets. In its anterior parts it shows a highly developed basal labyrinth and an abundance of secretory granules. The vagina has several layers of muscle cells in the basal lamina. Its epithelium contains few organelles, a small number of secretory granules, and is devoid of storage deposits.     

Odor detection ability and thallium-201 transport in the olfactory nerve of traumatic olfactory-impaired mice

Although olfactory nerve damage is a contributing factor in the diagnosis of posttraumatic olfactory loss, at present, there are no methods to directly assess injury to these nerves. We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. To determine if olfactory function after nerve injury could be assessed with nasal administration of 201 Tl, we measured the correlation between odor detection ability (ODA) and the rate of transport of 201 Tl in olfactory nerves. Both ODA and 201 Tl transport were measured after bilateral olfactory nerve transection for a 4-week period. Cycloheximide solution was used for ODA against tap water. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry. There was a significant correlation between ODA and the rate of 201 Tl transport in the olfactory nerve. These findings suggest that olfactory function after nerve injury can be objectively evaluated with the nasal administration of 201 Tl.