Ontogeny and homology of the basipterygoid articulation in Pantodon buchholzi (Teleostei: Osteoglossomorpha)

The basipterygoid articulation, an articular connection between the base of the braincase and the palatoquadrate, is widespread among gnathostome vertebrates. However, among living teleosts it is present only in the osteoglossomorphs Arapaima , Heterotis , Scleropages , Osteoglossum and Pantodon . Study of the development of the hyopalatine arch and the basipterygoid articulation in Pantodon buchholzi based on an ontogenetic series of cleared and double stained specimens yielded the following results: the symplectic process of the hyosymplectic cartilage never develops and the symplectic is absent; the pars hyomandibularis fuses with the palatoquadrate; the dermopalatine and ectopterygoid originate as separate bones, but fuse subsequently; the basal process is first visible on the pars metapterygoidea of the palatoquadrate at 7.0 mm standard length (SL); at 11.5 mm SL the basipterygoid process appears on the parasphenoid and contacts the basal process, establishing the basipterygoid articulation; the endopterygoid is initially not involved in the articulation, but during subsequent development enlarges and eventually forms an articular groove for the reception of the basipterygoid process of the parasphenoid; the distal tip of the basal process of the metapterygoid, however, still forms the caudolateral part of the articular groove in the adult. We discuss previous hypotheses about the homology of the basipterygoid articulation of osteoglossoids in light of these findings. Based on the numerous shared similarities and its occurrence in all major actinopterygian lineages, we argue that the basipterygoid articulation in osteoglossoids is homologous to that in non teleostean actinopterygians and represents a plesiomorphic character state at the level of Osteoglossomorpha.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 144 , 1−13.     

The basicranium of dicynodonts (Synapsida) and its use in phylogenetic analysis

Current phylogenetic hypotheses for the dicynodonts conflict, probably because the characters used, especially those of the jaws and facial region, show considerable convergence. Characters of the braincase and basipterygoid articulation of the Late Permian–Middle Triassic dicynodonts Diictodon , Dicynodon , Kingoria, Lystrosaurus , Rechnisaurus , and 14 other genera, may have phylogenetic value. Parsimony analysis and the character compatability permutation test suggest, at the highest possible confidence level, that the data set contains significant hierarchical structure, interpreted as a result of phylogeny. The most parsimonious tree broadly agrees with all recent hypotheses on the relationships among dicynodonts. However, it conflicts with the recent suggestion that Lystrosaurus is part of a clade of Middle–Late Triassic dicynodonts, but supports the basal position of Kingoria . The use of Eodicynodon as an outgroup does not perturb the parsimonious relationship of the included taxa. Topological constraints reveal that phylogenetic hypotheses based only on basicranial characters are not robust. Characters of the basipterygoid articulation and inner braincase have high consistency and retention indices, which suggests that the main evolutionary transformations in the dicynodont basicranium occurred within these structures.     

Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae)

Mayr, G. (2011) Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae). —Zoologica Scripta, 40, 448–467. The extinct Cenozoic bony‐toothed birds (Pelagornithidae) are characterized by the occurrence of unique spiky projections of the osseous jaws and are among the most distinctive neornithine taxa. Earlier authors considered these marine birds to be most closely related to ‘Pelecaniformes’ or Procellariiformes, but recent phylogenetic analyses resulted in a sister group relationship to Anseriformes. This latter hypothesis was, however, coupled with a non‐monophyly of galloanserine or even neognathous birds, which is not supported by all other current analyses. The character evidence for anseriform affinities of pelagornithids is thus reassessed, and it is detailed that the alleged apomorphies cannot be upheld. Pelagornithids lack some key apomorphies of galloanserine birds, and analysis of 107 anatomical characters did not support anseriform affinities, but resulted in a sister group relationship between Pelagornithidae and Galloanseres. By retaining a monophyletic Galloanseres, this result is in better accordance with widely acknowledged hypotheses on the higher‐level phylogeny of birds. The (Pelagornithidae + Galloanseres) clade received, however, only weak bootstrap support, and some characters, such as the presence of an open frontoparietal suture, may even support a position of Pelagornithidae outside crown‐group Neognathae.     

Vorkommen und Ausbildung der Fingerkrallen bei rezenten V?geln

Zusammenfassung Mit vorliegender Studie werden die Lücken der Kenntnisse über das Vorkommen von Fingerkrallen bei rezenten Vögeln so weit geschlossen, daß nunmehr Vertreter aller Ordnungen und der meisten Familien untersucht sind. Die Gruppierung der Ordnungen nach dem Vorkommen bzw. Fehlen von Fingerkrallen zeigt die Tendenz ihrer Reduktion auf. Trotz solcher allgemeinen Tendenz gibt es Arten, bei denen die Fingerkrallen während der Ontogenese an Größe zunehmen. Einige funktionelle, ontogenetische und phylogenetische Aspekte werden diskutiert. Der Zusammenhang zwischen Rückbildung der Fingerkrallen und Flügelbefiederung ist angedeutet. Möglicherweise werden die Krallen durch Federn verdrängt, und ihre Funktion, schützende Hülle des Fingerendes zu sein, fällt weg. Zwei weitere Ursachen der Reduktion werden in Betracht gezogen: Veränderungen der Ontogenese und genetische Veränderungen. Während die Ergebnisse für die Taxonomie nur einen geringen Wert haben, sind sie für die Rekonstruktion der Evolution des Vogelflügels und die aktuelle Urvogelforschung von Bedeutung.

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Occurrence and expression of claws on fingers of recent birds

Summary The present study completes the gaps in our knowledge about the occurrence and expression of claws on fingers of recent birds in so far as individuals from all orders and from most families were examined. The results are presented in a systematic overview. The grouping of the orders according to the presence or absence of claws shows a tendency towards their reduction. However, in spite of this overall trend, there exist species in which the claws on the fingers increase in size during ontogeny. Several functional, ontogenetic and phylogenetic aspects are discussed. The correlation between reduction of the finger claws and wing feathering is mentioned. Probably the claws are ousted by feathers, and therefore their function can be explained as a protective sheath for the finger. Two further causes of reduction are considered: changes of the ontogeny and genetic changes. Although the results are of little value for taxonomy, they may be relevant for the reconstruction of the evolution of bird wings and for present research on the origin of birds.

     

The Nerve Supply to the Second Metamere Basicranial Muscle in Osteolepiform Vertebrates,with Some Remarks on the Basic Composition of the Endocranium

The endocranium of Devonian osteolepiforms includes four minor structures, called zygals, which probably represent cephalic vertebral elements belonging to the second, third, and fourth metameres. Also, the endocranium exhibits a partial segmentation in the form of vestiges of intrametameric articulations attributable to the anterior five metameres. Finally, the basicranial muscle of osteolepiforms, extending across the lower part of the endocranial articulation within the second metamere, is possibly supplied by a separate cranial nerve, for which the term nervus rarus is proposed. This hypothetical cranial nerve, which in osteolepiforms possibly emerges from the endocranium through a canal in the fourth metamere, is suggested to constitute, together with the trochlear nerve, the somatic motor component of the second cranionerval segment.     

Beschreibung und Durchführung der Impfaktion bei Zoovögeln im Zoo am Meer Bremerhaven gegen Aviäre Influenza, hervorgerufen durch das Virus H5N1

The avian influenza A virus (H5N1), which causes the bird flu is latently present in populations of wild birds. The Bremerhaven Zoo is subject to an especially high infection risk owing to its close proximity to the North Sea coast and to resting places of birds. As an alternative to drastically killing all birds in an event of infection, a vaccination campaign was initiated in May 2006 as part of the “Program of the Federal Republic of Germany for the Vaccination of Birds in Zoos against Bird Flu”. The campaign is carried out in cooperation with the responsible authorities. This required formal approval of the authorities was subject to multiple conditions, the fulfilment of which required a large logistic effort. Some issues remained unresolved after the campaign had been completed. It is unclear, for instance, whether or not the applied inoculation is sufficient to immunize infected zoo birds and in which time intervals the vaccination has to be repeated in the future. The legal basis for the handing over of inoculated zoo birds to other institutions is published in the Federal Gazette.     

The deep divergences of neornithine birds: a phylogenetic analysis of morphological characters

Consensus is elusive regarding the phylogenetic relationships among neornithine (crown clade) birds. The ongoing debate over their deep divergences is despite recent increases in available molecular sequence data and the publication of several larger morphological data sets. In the present study, the phylogenetic relationships among 43 neornithine higher taxa are addressed using a data set of 148 osteological and soft tissue characters, which is one of the largest to date. The Mesozoic non‐neornithine birds Apsaravis, Hesperornis, and Ichthyornis are used as outgroup taxa for this analysis. Thus, for the first time, a broad array of morphological characters (including both cranial and postcranial characters) are analyzed for an ingroup densely sampling Neornithes, with crown clade outgroups used to polarize these characters. The strict consensus cladogram of two most parsimonious trees resultant from 1000 replicate heuristic searches (random stepwise addition, tree‐bisection‐reconnection) recovered several previously identified clades; the at‐one‐time contentious clades Galloanseres (waterfowl, fowl, and allies) and Palaeognathae were supported. Most notably, our analysis recovered monophyly of Neoaves, i.e., all neognathous birds to the exclusion of the Galloanseres, although this clade was weakly supported. The recently proposed sister taxon relationship between Steatornithidae (oilbird) and Trogonidae (trogons) was recovered. The traditional taxon “Falconiformes” (Cathartidae, Sagittariidae, Accipitridae, and Falconidae) was not found to be monophyletic, as Strigiformes (owls) are placed as the sister taxon of (Falconidae + Accipitridae). Monophyly of the traditional “Gruiformes” (cranes and allies) and ”Ciconiiformes” (storks and allies) was also not recovered. The primary analysis resulted in support for a sister group relationship between Gaviidae (loons) and Podicipedidae (grebes)—foot‐propelled diving birds that share many features of the pelvis and hind limb. Exclusion of Gaviidae and reanalysis of the data set, however, recovered the sister group relationship between Phoenicopteridae (flamingos) and grebes recently proposed from molecular sequence data.     

Juvenile cranial anatomy of Nimravidae (Mammalia, Carnivora): biological and phylogenetic implications

The anatomy of the spectacular sabretoothed carnivorans has been studied many times. Their behavioural and biomechanical implications are well known in adults, but not in juvenile individuals, which are poorly represented in the fossil record. This work reports on a newly discovered Hoplophoneini (Nimravidae Nimravinae) of 5–6 months of age, which represents the earliest and one of the most complete juvenile crania discovered. We discuss and compare the juvenile anatomy of Palaeogene nimravids relative to that of other mammals, especially other carnivorans including the Miocene nimravids (i.e. Barbourofelinae). We also discuss the ontogenetic development of this individual and other sabretoothed predators, which provides important data for reconstructing the biology of these extinct predators. Our study of the juvenile anatomy of the Hoplophoneini reveals an original association of basicranial features: the ectotympanic rotates away from the cranium earlier than in other mammals, which may be an additional autapomorphy distinguishing the Palaeogene Nimravidae from other Carnivora; within Palaeogene Nimravidae, at a similar ontogenetic stage, there is a major difference in development and maximum ventral extension of ossification of the caudal entotympanic; in contrast to the Miocene nimravid Barbourofelis, there is no strong relationship between the eruption of the upper canines and the development of other sabretoothed features (especially the mandibular flange) in the individual described. These results confirm the conclusions of recent studies which suggested that Palaeogene Nimravidae (Nimravinae) and Miocene Nimravidae (Barbourofelinae) are not closely related. Muscular reconstruction and biomechanical models also confirmed that juvenile individuals were probably not able to kill or hunt any prey. They may have fed on carcasses, eating muscles by using the incisors, and associated with a pulling or twisting action of neck. © 2003 The Linnean Society of London. Zoological Journal of the Linnean Society, 2003, 138 , 477–493.     

Morphology and evolution of the ectethmoid-mandibular articulation in the meliphagidae (Aves)

The ectethmoid-mandibular articulation in Melithreptus and Manorina (Meliphagidae: Aves) consists of the dorsal mandibular process fitting into and abutting against the ventral ectethmoid fossa; it forms a brace for the mandible. This articulation in Melithreptus is a typical diarthrosis with long folded capsular walls. The mandible, thus, has two separate articulations, each with a different axis of rotation. No other genus of Meliphagidae (except Ptiloprora) or any other avian family possesses a similar feature. The jaw and tongue musculature of Melithreptus are described. The two muscles opening the jaws are well developed, while those closing the jaws are small. The tongue muscles show no special developments. A large maxillary gland, presumably muscus secreting, covers the ventral surface of the jaw muscles. Its duct opens into the oral cavity just behind the tip of the upper jaw. The frilled tip of the tongue rests against the duct opening. The ectethmoid-mandibular articulation braces the adducted mandible against dorsoposteriorly directed forces. The mandible can be held closed without a compression force exerted by the mandible on the quadrate, permitting the bird to raise its upper jaw with greater ease and less loss of force. The tongue can be protruded through the slight gap between the jaws, moving against the duct opening and thus be coated with mucus. Presumably, these birds capture insects with their sticky tongue. Hence, the ectethmoid-mandibular articulation is an adaptation for this feeding method; it evolved independently in three genera of the Meliphagidae. The ectethmoid-mandibular articulation demonstrates that a bone can have two articulations with different axes of rotation, that the two articular halves can separate widely, and that articular cartilages can be flat and remain in contact over a large area. Its function suggests that the basitemporal articulation of the mandible found in many other birds has a similar function. And it demonstrates that in the evolution of the mammalian dentary-squamosal articulation, the new hinge did not have to lie on the same rotational axis as the existing quadrate-articular hinge.     

Bird speech perception and vocal production: a comparison with humans

Research into speech perception by nonhuman animals can be crucially informative in assessing whether specific perceptual phenomena in humans have evolved to decode speech, or reflect more general traits. Birds share with humans not only the capacity to use complex vocalizations for communication but also many characteristics of its underlying developmental and mechanistic processes; thus, birds are a particularly interesting group for comparative study. This review first discusses commonalities between birds and humans in perception of speech sounds. Several psychoacoustic studies have shown striking parallels in seemingly speech-specific perceptual phenomena, such as categorical perception of voice-onset-time variation, categorization of consonants that lack phonetic invariance, and compensation for coarticulation. Such findings are often regarded as evidence for the idea that the objects of human speech perception are auditory or acoustic events rather than articulations. Next, I highlight recent research on the production side of avian communication that has revealed the existence of vocal tract filtering and articulation in bird species-specific vocalization, which has traditionally been considered a hallmark of human speech production. Together, findings in birds show that many of characteristics of human speech perception are not uniquely human but also that a comparative approach to the question of what are the objects of perception--articulatory or auditory events--requires careful consideration of species-specific vocal production mechanisms.     

First evidence of dinosaurian secondary cartilage in the post-hatching skull of Hypacrosaurus stebingeri (Dinosauria, Ornithischia)

Bone and calcified cartilage can be fossilized and preserved for hundreds of millions of years. While primary cartilage is fairly well studied in extant and fossilized organisms, nothing is known about secondary cartilage in fossils. In extant birds, secondary cartilage arises after bone formation during embryonic life at articulations, sutures and muscular attachments in order to accommodate mechanical stress. Considering the phylogenetic inclusion of birds within the Dinosauria, we hypothesized a dinosaurian origin for this "avian" tissue. Therefore, histological thin sectioning was used to investigate secondary chondrogenesis in disarticulated craniofacial elements of several post-hatching specimens of the non-avian dinosaur Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae). Secondary cartilage was found on three membrane bones directly involved with masticatory function: (1) as nodules on the dorso-caudal face of a surangular; and (2) on the bucco-caudal face of a maxilla; and (3) between teeth as islets in the alveolar processes of a dentary. Secondary chondrogenesis at these sites is consistent with the locations of secondary cartilage in extant birds and with the induction of the cartilage by different mechanical factors - stress generated by the articulation of the quadrate, stress of a ligamentous or muscular insertion, and stress of tooth formation. Thus, our study reveals the first evidence of "avian" secondary cartilage in a non-avian dinosaur. It pushes the origin of this "avian" tissue deep into dinosaurian ancestry, suggesting the creation of the more appropriate term "dinosaurian" secondary cartilage.     

Tagesperiodische Schwankungen der Vorzugshelligkeit bei Vögeln

Zusammenfassung 7 Stare (Sturnus vulgaris), 2 Beos (Gragula religiosa) und 1 Amsel (Turdus merula) wurden einzeln für jeweils mindestens 14 Tage in einer Apparatur gehalten, in der sie zwischen zwei oder drei unterschiedlich hell, aber zeitlich konstant beleuchteten Kästen wählen konnten. In jedem Kasten wurde ihre lokomotorische Aktivität registriert. Acht der zehn Vögel zeigten eine circadiane Periodik der Aktivität und, korreliert da mit, eine circadiane Periodik der bevorzugten Beleuchtungsstärke; die Vorzugshelligkeit nahm bei steigender Gesamtaktivität zu; zum Schlafen suchten die Vögel stets den dunkleren Kasten auf. Diese strenge Korrelation zwischen Aktivitätsmenge und Vorzugshelligkeit galt bei einem Tier nur für bestimmte Teile seiner Aktivitätsperiodik, im übrigen aber auch für solche Vögel, deren Aktivität in kurzperiodischen Schüben geordnet oder aperiodisch war.Es wird auf die ökologische Bedeutung dieser Befunde hingewiesen und die Frage nach möglichen Konsequenzen für die Tierhaltung erörtert.

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Summary 7 Starlings (Sturnus vulgaris), 2 Beos (Gracula religiosa) and 1 Blackbird (Turdus merula) were kept for at least 14 days, each in isolation, in an apparatus in which they were able to chose between 2 or 3 chambers with different, but constant, light intensities. Locomotor activity was measured in each chamber. 8 of 10 birds exhibited, at least temporarily, a circadian rhythm of activity and correllated to it a circadian rhythm in the preferred light intensity: the preferred intensity increased with increasing activity, and the birds always selected the dark chamber for sleeping. This close correlation between activity level and preferred light intensity was absent only in one animal at particular times of his period, and was otherwise typical also for birds with frequent periodic or aperiodic bursts of activity. The ecological significance of these findings is discussed, and possible consequences for the maintenance of animals in captivity are considered.

     

Why do Juvenile Chinese Pit‐Vipers (Gloydius shedaoensis) Select Arboreal Ambush Sites?

Ontogenetic shifts in habitat use are widespread, especially in ectothermic taxa in which juveniles may be an order of magnitude smaller than large adult conspecifics. The factors that generate such habitat shifts are generally obscure, but we studied an unusual system that allowed us to compare consequences of habitat selection between adults and juveniles. Pit‐vipers (Gloydius shedaoensis) on a small island in north‐eastern China feed almost entirely on seasonally migrating birds. During the spring bird‐migration period, individual snakes consistently re‐used either arboreal or terrestrial ambush sites. Snakes in trees were smaller (and more philopatric) than snakes on the ground. This ontogenetic shift in habitat use may reflect the difficulty of capturing birds on the ground, especially by small snakes. In laboratory trials, large (adult) pit‐vipers struck faster, further and more accurately than did small (juvenile) snakes. In experiments with free‐ranging snakes, the proportion of strikes hitting the bird was lower for juveniles than for adults, and lower for terrestrial snakes than for arboreal snakes. Additionally, adult snakes generally seized the bird by the head whereas juveniles frequently struck the body or wings (and thus, obtained a less secure grip). Arboreal ambush sites may facilitate prey capture not only because they give access to smaller birds but also because they render the bird's location more predictable and, hence, enable the snake to position itself optimally prior to the prey's arrival. Because juvenile pit‐vipers are less capable strikers, and are small relative to available prey items, they may benefit from the greater ease of prey capture from branches. Thus, the ontogenetic shift in habitat selection within this species may be because of ontogenetic shifts in the vipers’ ability to capture and ingest large, mobile prey.     

Flightlessness affects cranial morphology in birds

Flightless birds belonging to phylogenetically distant clades share several morphological features in the pectoral and pelvic apparatus. There are indications that skull morphology is also influenced by flightlessness. In this study we used a large number of flightless species to test whether flightlessness in modern birds does indeed affect cranial morphology. Discriminant analyses and variation partitioning show evidence for a relationship between skull morphology and the flightless condition in birds. A possible explanation for the change in cranial morphology can be linked to the reduced selective force for light-weight skulls in flightless birds. This makes an increase in muscle mass, and therefore an enlargement of muscle insertion areas on the skull, possible. We also compared the ontogenetic trajectory of Gallus with the adult morphology of a sample of flightless species to see whether the apomorphic features characterizing the skull of flightless birds share the same developmental basis, which would indicate convergent evolution by parallelism. Skull morphology (expressed as principal component scores) of palaeognathous flightless birds (ratites) is dissimilar (higher scores) to juvenile stages of the chicken and therefore seem peramorphic (overdeveloped). Principal component scores of adult neognathous flightless birds fall within the range of chicken development, so no clear conclusions about the ontogenetic trajectories leading to their sturdier skull morphology could be drawn.     

Flapping before Flight: High Resolution,Three-Dimensional Skeletal Kinematics of Wings and Legs during Avian Development

Some of the greatest transformations in vertebrate history involve developmental and evolutionary origins of avian flight. Flight is the most power-demanding mode of locomotion, and volant adult birds have many anatomical features that presumably help meet these demands. However, juvenile birds, like the first winged dinosaurs, lack many hallmarks of advanced flight capacity. Instead of large wings they have small “protowings”, and instead of robust, interlocking forelimb skeletons their limbs are more gracile and their joints less constrained. Such traits are often thought to preclude extinct theropods from powered flight, yet young birds with similarly rudimentary anatomies flap-run up slopes and even briefly fly, thereby challenging longstanding ideas on skeletal and feather function in the theropod-avian lineage. Though skeletons and feathers are the common link between extinct and extant theropods and figure prominently in discussions on flight performance (extant birds) and flight origins (extinct theropods), skeletal inter-workings are hidden from view and their functional relationship with aerodynamically active wings is not known. For the first time, we use X-ray Reconstruction of Moving Morphology to visualize skeletal movement in developing birds, and explore how development of the avian flight apparatus corresponds with ontogenetic trajectories in skeletal kinematics, aerodynamic performance, and the locomotor transition from pre-flight flapping behaviors to full flight capacity. Our findings reveal that developing chukars (Alectoris chukar) with rudimentary flight apparatuses acquire an “avian” flight stroke early in ontogeny, initially by using their wings and legs cooperatively and, as they acquire flight capacity, counteracting ontogenetic increases in aerodynamic output with greater skeletal channelization. In conjunction with previous work, juvenile birds thereby demonstrate that the initial function of developing wings is to enhance leg performance, and that aerodynamically active, flapping wings might better be viewed as adaptations or exaptations for enhancing leg performance.     

Zur Kontrolle von Fortpflanzungszyklen bei Vögeln

Summary Under the natural light conditions of Kiel the maximal AChE-activity of the pars distalis of male bramblings (group N) is correlated with highest testes weight, widest diameter of seminiferous tubules, darkest bill color, and widest diameter of seminal vesicles (Fig. 1, Fig. 2). AChE-cells first appear at the end of Jan. and almost completely disappear at the beginning of the photorefractory period. At this time large amounts of lipids can be observed in the seminiferous tubules and the interstitial tissue. These lipids gradually disappear during fall and winter. At the end of Jan. and in Feb. fat droplets are selectively deposited in differentiating Leydig-cells.Under constant longday conditions (20L4D, group L, beginning in October) the tubule and interstitial lipids disappear as they did in group N. The characteristics of the refractory period (no AChE-cells, minimal testicular weight, minimal diameter of seminiferous tubules and seminal vesicles, yellow bill color) are maintained over 13 months until the end of the experiment (Fig. 3, Fig. 4). Only 3 out of 51 birds showed a gonadal cycle.Under shortday conditions (8L 16D, group K, beginning in October) no essential differences to groups N and L can bee seen during the first months (Fig. 5). By the end of January AChE-positive cells develop in the pars distalis, testes weight and diameter of seminiferous tubules increase slowly, and Leydig-cells differentiate and incorporate lipids. From July until the end of the experiment a steady state can be observed (Fig. 6). The AChE-cells are about as numerous as in May in group N, but are smaller and more irregularly shaped. The testes are 4 times heavier than during the winter, but reach only about 1% of the maximal weight of group N (Fig. 5). No testosterone secretion is indicated by the sexhormone dependent structures.Photosensitive males can be rapidly and prematurely stimulated by longdays to undergo the alterations observed in group N during spring. Castrated photosensitive birds react to longdays with a spectacular hyperplasia and hypertrophy of the AChE-cells. This reaction is evidence that these cells have a gonadotropic function.Castration and shortday treatment (beginning in October) do not lead to hyperplastic and hypertrophic alterations of the AchE-cells until May. This indicates the existence of a negative feedback between the testes and the hypo-thalamo-pituitary system even at a time when no testosterone secretion can be recognized at the sexhormone dependent structures. Treatment with testosterone causes the AChE-cells which developed under shortday conditions to disappear.Several observations (ultrastructural localization of AChE, parallelism of gonadotropin content and AChE-activity, and high AChE-activity and high gonadotropin content together with undeveloped gonads) indicate that AChE is involved in hormone synthesis and that gonadotropin synthesis and release can be controlled separately. While synthesis may occur under shortday conditions long-days are necessary for release. Testosterone can inhibit GTH-synthesis and release.In groups L and K no circannual oscillations could be detected. Therefore the seasonal changes in day length must be considered as the cause of the annual reproduction rhythm in bramblings. An hour glass model is constructed which uses the circadian photosensitivity phases and their threshold-shifts to connect endogenously and exogenously controlled rhythms.

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Als Habilitationsschrift zur Erlangung der Venia legendi in Zoologie von der Mathematischen-Naturwissenschaftlichen Fakultät der Christian Albrechts-Universität Kiel im WS 1971/72 angenommen.     

†Kinzelbachilla ellenbergeri – a new ancestral species,genus and family of Strepsiptera (Insecta)

A single male specimen of a new species (†Kinzelbachilla ellenbergeri gen. et sp.n. ) of a new family of the endoparasitic Strepsiptera (†Kinzelbachillidae fam.n.) from Burmese amber is described and evaluated with respect to its systematic placement. Its features come very close to the presumptive groundplan of the order suggested in recent studies. Preserved plesiomorphic features are the following: fully sclerotized head with long coronal suture, small ommatidia not separated by chitinous bridges, absence of microtrichia between ommatidia, eight antennomeres, robust mandibles with dicondylic articulation, galea distinctly developed, free pro‐ and mesotrochanters, slender five‐segmented tarsi without adhesive soles, and equally sclerotized abdominal tergites and sternites. An important character that is not recognizable due to damage is the shape of the metapostnotum. This structure is transverse in the groundplan of Strepsiptera and in †Protoxenos, but elongated and shield‐like in all other known strepsipterans. In a cladistic analyses of 82 characters of adult males and additional characters for females and immatures (scored as unknown for all included fossils) †Kinzelbachilla is placed as sister group of all remaining strepsipterans except for †Protoxenos, followed by †Cretostylops and †Mengea as the third and fourth branches in the stem group, respectively. The position of †Protoxenos as first branch is suggested by three unambiguous apomorphic features of all remaining Strepsiptera, the reduced size of less than 6 mm, mandibles distinctly narrowing distad the basalmost part, and fan‐shaped hindwings which are broader than they are long. The hitherto known fossil stem group strepsipterans do not distinctly narrow the large morphological gap separating this order from its sister group, the Coleoptera. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:07554C01-DEC3-4080-A337-B1F46BC9070F .     

Development of cardiac rhythms in birds

Heart rate (HR) in avian embryos developing inside an eggshell has been measured by various means while maintaining adequate gas exchange through the eggshell. This is an important requirement in order to avoid adverse effects of impeding gas exchange on the cardiac rhythms of developing embryos. The present report is a review of our ontogenetic study on embryonic HR, which was measured with fulfillment of the above requirement and also hatchling HR measured non-invasively. Firstly, we reviewed measurements of daily changes (developmental patterns) in embryonic mean heart rate (MHR), which were determined from a short-term measurement of HR once a day, in 34 species of altricial and precocial birds. The allometric relationship between the MHR during pipping in altricial birds and their fresh egg masses was the same as that between the MHR at 80% of incubation duration and fresh egg masses in pre-cocial birds. Secondly, we presented the developmental patterns of MHR in chick embryos and hatchlings, which were determined from long-term, continuous measurement of HR before, during and after hatching. The ultradian and circadian rhythms of HR were clearly shown in embryos and hatchlings, respectively. Thirdly, we summarized instantaneous HR fluctuations: HR variability and HR irregularities, in chick embryos and hatchlings. The distinctive patterns were shown in pre-pipped and pipped embryos and newly hatched chicks, individually, which were partly related to autonomic nervous functions and physiological functions.