Ontogeny of the hyobranchial apparatus in the salamanders Ambystoma talpoideum (Ambystomatidae) and Notophthalmus viridescens (Salamandridae): The ecological morphology of two neotenic strategies

Comparison of metamorphosis of skull and hyobranchial system in two species of neotenic salamanders reveals two different types of neoteny. Ambystoma talpoideum is completely neotenic owing to delayed metamorphosis. Notophthalmus viridescens exhibits limited neoteny as a result of incomplete metamorphosis. Morphological details of neoteny are compared to life history in both species in order to discuss the ecological morphology of the two neotenic strategies. Comparisons to Taricha granulosa, Triturus vulgaris, and Ambystoma gracile indicate that these two strategies are widely employed and may represent familial patterns.     

Die Ausbildung der Asymmetrie der Nuclei habenulae des Zwischenhirns bei Amphibien in Unabhängigkeit vom Blutkreislauf

Zusammenfassung Zur Prüfung der Fräge, ob der Blutkreislauf bei der Bestimmung der Asymmetrie der Nuclei habenulae des Zwischenhirns eine Rolle spielt, wurden Larven vonTriturus alpestris ohne Blutkreislauf durch Entfernung der Herzanlage hergestellt. Die Nuclei habenulae entwickelten auch ohne Kreislauf ihre normale Asymmetrie.Isolate aus dem Kopfbezirk der Neurula vonTriturus alpestris, die aus cephalem Ekto und Mesoderm bestanden und manchmal auch vorderes Entoderm enthielten, entwickelten in günstigen Fallen an ihrem Gehirn die Nuclei habenulae. Diese besaßen trotz Abwesenheit von Blutkreislauf und der anderen asymmetrischen Organe die normale Asymmetrie.

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The development of asymmetrical nuclei habenulae in the diencephalon of amphibians, independent of blood circulation

Summary The problem whether the blood circulation influences or determines the asymmetry of Nuclei habenulae was tested by removing the heart-anlage of the embryo ofTriturus alpestris. The resulting larvae without any blood circulation developed their normal asymmetry of habenulae.Isolates from the head region of neurulae ofTriturus alpestris, consisting of cephalic ecto and mesoderm, sometimes also of entoderm, under favorable conditions could develop brains with Nuclei habenulae. These were normal, asymmetric in spite of missing the blood circulation and other asymmetrical organs.

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Ausgefürhrt mit Unterstützung der Deutschen Forschugagemeinschaft.     

Gesamtbestand an organischen Substanzen der Spinne Tegenaria atrica im Vergleich zu Protophormia terrae novae (Diptera) und Orconectes limosus (Crustacea,Decapoda)

Zusammenfassung Die Pulsationen der Lymphherzen von Normaltieren von Triturus vulgaris L. und T. alpestris Laur. sind unregelmäßig und verändern sich bei Erregung der Tiere. Die Lymphherzfrequenzen sind temperaturabhängig und folgen der R-G-T-Regel. Der Q ₁₀ beträgt bei T. vulgaris 2,5, bei T. alpestris 2,1. In Narkose oder bei Spinaltieren sinkt die Lymphherzfrequenz gegenüber der von Normaltieren ab, der Rhythmus wird regelmäßig. Bei Spinaltieren tritt homolaterale Synchronie auf. Jedes Lymphherz hat ein eigenes motorisches Zentrum im Rückenmark; die Impulse werden über Spinalnerven geleitet. Die Ergebnisse werden mit den von Anuren bekannten verglichen.

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Physiological investigations on the lymph hearts of urodelans

Summary The heart beats of normal individuals of Triturus vulgaris L. and T. alpestris Laur. are irregular and can be altered by excitation of the animal. The frequencies vary with alterations in temperature according to the rule of van t'Hoff. The Q ₁₀ was measured as 2.5 for T. vulgaris and 2.1 for T. alpestris. In anesthetized and in spinal animals the frequencies are strongly reduced and the pulsations become regular. Spinal animals show homolateral synchrony of the lymph heart beats. The motor centres, separated for each lymph heart, are situated in the spinal cord; the impulses are mediated by spinal nerves. The results are compared with those of the Anurans.

     

Sexual size and shape evolution in European newts (Amphibia: Caudata: Salamandridae) on the Balkan Peninsula

We used a phylogenetic perspective in an examination of the direction and extent of sexual dimorphism in body size and body shape in European newts from the Balkan Peninsula (alpine newts, Mesotriton alpestris; crested newts, Triturus cristatus superspecies; smooth newts, Lissotriton vulgaris). We found a strong, female‐biased sexual size dimorphism (SSD) in the analysed clades of alpine newt, whereas within crested newts we found a less stringent female‐biased SSD in Triturus carnifex, Triturus macedonicus and Triturus karelinii, and no significant SSD in T. cristatus or Triturus dobrogicus. Among the smooth newts, we found male‐biased SSD in Lissotriton vulgaris vularis and Lissotriton vulgaris greacus and no SSD in Lissotriton vulgaris meridionalis. Most of these newts also exhibit a significant sexual dimorphism in body shape, which varied more randomly than body size, regardless of SSD level. Female and male body size as well as the degree of SSD displayed statistically significant phylogenetic signal, while sexual dimorphism in body shape was phylogenetically independent. The relationship between independent contrast data for female size and male size indicated that SSD in European newts could be driven by a disproportionate increase in female size as increase in female size was not accompanied by a proportional increase in male size.     

Auslösung von Situs inversus durch Materialdefekte im lateralen Ektoderm der Gastrula beiTriturus alpestris

Zusammenfassung Bei jungen Gastrulen vonTriturus alpestris wurden in der Gegend des lateralen Poles des Keims rundliche Stücke entnommen, welche hauptsächlich undeterminiertes Ektoderm und teilweise ein wenig ventrales Mesoderm enthielten. Die Keime entwickelten sich in der Mehrzahl der Fälle zu äußerlich normalen Keimen oder zeigten nur geringe Entwicklungsstörungen.Bei linksseitiger Entnahme (101 Fälle) war der Situs des Darmtraktes in 85,2% der Fälle regulär, in 6,9% median und in 7,9% invers. Bei rechtsseitiger Entnahme (106 Fälle) war der Situs in 79,2% normal, in 8,5% median und in 12,3% invers.Das Ergebnis unterstützt die Befunde v.Krafts (1968b), der durch Bestrahlung einer entsprechenden Keimregion mit UV-Licht ebenfalls eine höhere Inversionswirkung bei rechtsseitiger Bestrahlung gefunden hatte. Der Gegensatz dieser Befunde zu der höheren linksseitigen Wirksamkeit von Eingriffen an anderen Keimbezirken und -Stadien wird erörtert.Der frühere Befund höherer Wirksamkeit linksseitiger Defekte im Organisatorbereich wurde an Stichproben bestätigt.

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Provocation of situs inversus by means of material defects in the lateral ectoderm of the gastrula ofTriturus alpestris

Summary Roundish pieces were removed from the lateral polar region of young gastrulae ofTriturus alpestris. These consisted mainly of undetermined ectoderm and partly of ventral mesoderm. The majority developed into normal embryos or embryos with minor abnormalities.After injury of the left side (101 cases) the gut situs of the larvae was normal in 85.2% median in 6.9% and inverted in 7.9%. When injured on the right side (106 cases), the larval gut situs was regular in 79,2%, median in 8.5% and inverted in 12.3%.These results support the statements of v.Kraft (1968b) who also found a higher rate of situs inversus after irridiation of the right side. In contrast, defects on the left side are more effective in other regions and different stages of the embryo. The higher sensitivity for defects of the left side in the organizer region (v.Woellwarth, 1950) could be confirmed.

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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Di‐ and tetranucleotide microsatellite markers for the Alpine newt (Triturus alpestris): characterization and cross‐priming in five congeners

We developed a set of di‐ and tetranucleotide microsatellite markers for the Alpine newt, Triturus alpestris. Polymorphism as detected in 39 individuals ranged from 3 to 32 alleles at a locus. Cross‐priming with samples of five other Triturus species showed extremely poor levels of cross‐species utility. Still, these markers are suitable for studies of inter‐ and intrapopulation genetic diversity in the focal species.     

Endocrine-like cells in the lungs of the newt,Triturus alpestris Laur.

Summary Endocrine-like cells (ELC) scattered in the basal part of the ciliated epithelium were identified in the lungs of the newt, Triturus alpestris. These ELC have a clear cytoplasm containing large amounts of secretory vesicles (69–180 nm in diameter), especially in their basal parts, but do not display formaldehyde-induced fluorescence. The ELC may be associated with nerve fibres.     

Identification of pigment cells during early amphibian development (Triturus alpestris,Ambystoma mexicanum)

Summary The purpose of the present investigation was to provide and apply a methodological manual with which the distribution, patterning and relationship of melanophores and xanthophores can be analyzed during early amphibian development. For demonstration of the methods, which include ultrastructural, histochemical and biochemical approaches, Triturus alpestris and Ambystoma mexicanum (axolotl) embryos are used. These two species differ conspicuously in their larval pigment patterns, showing alternating melanophore bands in horizontal (T. alpestris) and vertical (axolotl) arrangements. With transmission- and scanning electron microscopy melanophores and xanthophores were distinguished by their different pigment organelles and surface structures. The presence of phenol oxidase (tyrosinase) was used to reveal externally invisible or faintly visible melanophores by applying an excess of 3,4 dihydroxy-phenylalanine (dopa). Xanthophores were made visible in fixed and living embryos by demonstrating their pterin fluorescence. In addition, pterins were analyzed by HPLC in embryos before and after pigmentation was visible.Abbreviations DOPA dihydroxy-phenylalanine - FCS fetal calf serum - FIF formaldehyde-induced fluorescence - FITC fluorescein isothiocyanate - HPLC high performance liquid chromatography Dedicated to the memory of Dr. Michael Claviez     

Chromosome differentiation in the Triturus alpestris complex (Amphibia: Caudata)

Several individuals from distinct populations of 7 subspecies included in the Triturus alpestris complex have been analysed to obtain characteristic C-banding patterns.The differences found among the populations as regards the amount, complexity and distribution of heterochromatin bands have been employed to test a pattern of chromosome evolution.Relevant similarities and dissimilarities of these populations are discussed in the light of the tentative evolutionary history inferred from a rooted tree.     

Corresponding defects in the dorsal fin and in the male breeding crest ofTriturus alpestris

Summary In a wild population ofTriturus alpestris several adult males with an incomplete breeding crest were found. Among the offspring from this population larvae with defects in the dorsal fin were observed. Neither the pigment cells nor the spinal ganglia appear affected in the deficient trunk region of larvae and adults.This work was supported by the Georg and Antoine Claraz-Schenkung. The author wishes to thank Mr. P. Diethelm for ceding the animals and Miss M. Eich for her technical assistance.     

Micro-habitat use within a guild of newt larvae (Trituridae) in an Alpine lake

Population and ecological parameters such as numbers of larvae, microhabitat use, niche breadth and niche overlap of three species of syntopic larval newts (Alpine newt Triturus alpestris, Italian crested newt T. carnifex, and common newt T. vulgaris) were studied for two years in a small pond at 1160 m a.s.l. in NE Slovenia. Differences in microhabitat partitioning among larval newts were small. The largest niche breadth was estimated for larval T. alpestris, and the narrowest estimate was for larval T. carnifex in both years. Ecological differences seem to be very small and quite variable among sites and years. It appears that the developmental stage and size of newt larvae are more important in explaining resource partitioning than the characteristics of each species. Because of the absence of potential invertebrate predators and adult newts in the second half of the breeding season, the injuries could only be caused by intra-and interspecific predation attempts.     

Hyobranchial skeleton and hypobranchial muscles of rhipidistians

The hyobranchial skeleton of the porolepiform rhipidistian Laccognathus panderi Gross is described. The double composition of the ceratohyal in crossopterygians is proposed. The urohyal of porolepiforms, like that of Latimeria, consists of cartilaginous axial and membranous peripheral portions. The differences between porolepiforms and osteolepiforms in the structure of the hyobranchial skeleton, particularly, in the shape of the urohyal are attributable to different arrangements of the hypobranchial muscles. Porolepiforms and coelacanths have retained the coracomandibularis muscle inherited from early gnathostomes, whereas the same muscle of osteolepiforms was transformed into the geniohyoideus muscle. This transformation is accounted for by functional changes in the hyobranchial apparatus.     

Der Eingeweidesitus beim Alpenmolch (Triturus alpestris) nach Materialdefekten im Ektoderm der Blastula

Zusammenfassung Im Blastulastadium vonTriturus alpestris wurden aus der animalen Hälfte des Keimes rundliche Stücke entnommen, welche aus undeterminiertem Ektoderm bestanden; einige konnten an ihrem vegetativen Rand vielleicht noch ein wenig Mesoderm enthalten. Da die Medianebene in diesen Stadien nicht feststellbar war, ist eine zufallsmäßige Verteilung um die animal-vegetative Achse anzunehmen.Die meisten Embryonen entwickelten sich zu äußerlich normalen Larven. Der Darmsitus von 193 Larven war in 97,9% der Fälle regulär, in 0,5% median und in 1,5% invers. Das entspricht der Inversionsrate nicht operierter Tiere.Mechanische Defekte durch Materialentnahme erzeugten also im Gegensatz zu ähnlichen Defekten im Gastrulastadium keine Eingeweideinversionen. (Bestätigung ähnlicher Ergebnisse v. Kraft's 1969 nach UV-Bestrahlung.) Die sensible Phase für die Erzeugung vonSitus inversus viscerum beginnt nach diesen Beobachtungen im Gastrulastadium.

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The situs viscerum in the newt (Triturus alpestris) after material defects in the ectoderm of the blastula

Summary In the blastula stage ofTriturus alpestris roundish pieces were removed from the animal half of the embryo, which consisted of undetermined ectoderm; some of them could perhaps contain some mesoderm on their vegetal edge. Since the median plane could not be ascertained in this stage, a chance distribution around the animal-vegetal axis has to be assumed.Most of the embryos developed to externally normal larvae. The gut situs of 193 larvae was regular in 97.9% of the cases, median in 0.5% and inverted in 1.5%. This corresponds to the inversion rate of non operated animals.Therefore mechanic defects by means of removing of material, in contrast to similar defects in the gastrula stage, provoked no gut inversions. (Confirmation of similar results of v. Kraft, 1969 following UV-irradiation). According to these observations the sensible phase for the provocation of situs inversus viscerum begins in the early gastrula stage.

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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Myosin isoenzymes and their subunits in urodelan amphibian fast skeletal muscle. Coexistence of larval and adult heavy chains in neotenic individuals

The distributions of native myosin isoforms were examined by electrophoresis under non-dissociating conditions, in the fast twitch dorsal skeletal muscle of young larvae, neotenic adults and metamorphosed adults of urodelan amphibians. Both heavy and light chains of myosin isoenzymes were analysed. In pyrophosphate acrylamide gel electrophoresis three isoenzymes were demonstrated in larval myosin; other isoforms of lower electrophoretic mobility were observed in metamorphosed adults myosin. Larval and adult isoenzymes were shown to coexist in myosin from neotenic adults. Analysis of heavy chains in denaturing conditions and proteolytic digestion revealed the sequential occurrence during development of two types of heavy chains, one larval and one adult, that coexist in the myosin of neotenic adults only. Analysis of light chain patterns under denaturing conditions revealed the existence of three fast light chains which displayed no modification during the course of development. The neotenic urodelan amphibian species model represents actually the only model in which the coexistence of larval (or neonatal) and adult heavy chains is maintained throughout life in adults.     

An immimohistochemical study of regulatory peptides in lungs of amphibians

Summary The lungs of five species of European Anura and one species of Urodela (Triturus alpestris) have been studied by immunohistochemical methods to determine the occurrence, localization and distribution of serotonin, neuron-specific enolase, and eight regulatory peptides reported in the mammalian respiratory tract.Single and groups of serotonin-immunoreactive cells, corresponding to neuroendocrine cells of the mammalian lung, were identified in lungs of all amphibian species studied. Immunoreactivity for neuron-specific enolase was localized mainly in pulmonary nerves, nerve cell bodies and neuroendocrine cells. The localization and distribution of regulatory peptides varied among species. Bombesin and gastrin-releasing peptide immunoreactivities (predominant peptides in human lung) were localized mostly in submucosal nerves. Single bombesin-immunoreactive cells were found only in lungs of Urodela, i.e., Triturus alpestris. Occasional single cells, immunoreactive for somatostatin and leu-enkephalin were identified in lungs of Bombina variegata and a few cholecystokinin-immunoreactive cells in Hyla arborea. In all anuran species, numerous substance P-immunoreactive nerves were identified in submucosa, pulmonary septa and around blood vessels. No immunoreactive cells or nerves were demonstrated with antibodies against calcitonin and vasoactive intestinal peptide.The term pulmonary neuroendocrine (NE) cells (used here) does not imply neural origin or classical endocrine function for these cells, but rather indicates their potential involvement in neurohormonal regulation of pulmonary function (Cutz 1982)Supported by grant to E.C. from Medical Research Council of Canada (MT-7641)     

The influence of group size on ovarian development in adult and neotenic reproductives of the termite Zootermopsis angusticollis (Hagen) (Hodotermitidae)

Termite imagines of Zootermopsis angusticollis (Hagen), while still in the colony as winged individuals, do not show ovary development, although vitellogenin is present in the blood at low levels. When removed from the colony, artificially dealated, and paired, vitellogenin levels rise: subsequently ovaries develop resulting in oviposition approximately 15–16 days after removal from the colony. Imagines removed from the colony, dealated and held together in a heterosexual group, however, show little or no ovary development after 25 days, although vitellogenin is present in the haemolymph in low levels. Newly developed neotenic reproductives, on the other hand, removed from the colonly 1–2 days after the neotenic moult, and isolated in heterosexual pairs for 60 days, had ovaries which did not become larger than 0.02 mm³, and no eggs were laid. This is in contrast to the normal ovary development of neotenic reproductives produced in groups of larvae, as described earlier. Vitellogenin levels in isolated pairs of neotenics were low until 25 days after isolation, while vitellogenin levels increased 7–9 days after the moult in female neotenics kept in a colony with larvae. The results of this study on ovarian development and vitellogenesis in neotenic and adult reproductives reflect the normal biology of the two reproductive types where the latter leave the colony to found new colonies, while neotenics become sexually mature within the colony in which they developed.     

Gross morphology and topographical relationships of the hyobranchial apparatus and laryngeal cartilages in the ostrich (Struthio camelus)

The ostrich hyobranchial apparatus consists of the centrally positioned paraglossalia and basiurohyale and paired caudo‐lateral elements (horns), each consisting of the ceratobranchiale and epibranchiale. The paraglossalia lie within the tongue parenchyma and consist of paired, flat, caudo‐laterally directed cartilages joined rostrally. The basiurohyale forms a single dorso‐ventrally flattened unit composed of an octagonal‐shaped body from which extend rostral (the rostral process) and caudal (the urohyale) projections. The laryngeal skeleton consists of cricoid, procricoid and paired arytenoid cartilages. The large ring‐shaped cricoid cartilage displays a body and paired wings which articulate with each other and with the procricoid. The blunt, ossified, rostral projection of the cricoid and the scalloped nature of the arytenoid cartilages are unique to the ostrich. The procricoid is a single structure which links the paired arytenoids and wings of the cricoid. The hyobranchial apparatus is firmly attached to the tongue parenchyma and to the larynx and proximal trachea. In contrast to previous reports in this species, the horns of the hyobranchial apparatus are not related to the skull. Ossification of the body of the basihyale, the ceratobranchials and the rostral process and body of the cricoid cartilage of the larynx lends stability to these structures.     

The bryophytes of Greece: new records and observations

Abstract

New records of 38 hepatics and 87 mosses are reported from Greece. Leiocolea heterocolpos, Cephaloziella calyculata, Dicranella schreberiana, Hennediella stanfordensis, Weissia levieri, Grimmia alpestris and Grimmia torquata are believed to be new to the country. Claviform propagules formed by the excurrent nerve of the leaf are reported from a collection of Trichostomopsis australasiae.     

Amino acid transport and protein synthesis in induced ectoderm of amphibian embryos

Summary Isolated gastrula ectoderm ofTriturus alpestris orAmbystoma mexicanum was induced by the vegetalizing factor. Protein synthesis in the induced and uninduced control explants was measured by double labelling with³H-and¹⁴C-amino acids after different periods of cultivation. Slight differences were observed in the pattern of nuclear proteins after 12 h of cultivation and in the pattern of cytoplasmic proteins after 48 h of cultivation.The uptake of leucine started to increase in induced explants after 48 h of cultivation and after 96 h was about 50 times greater than in uninduced control explants. The uptake is reduced under partially anaerobic conditions. Ouabain inhibits the uptake by about 50%.