The dissection of the heads of three adult roe deer (Capreolus capreolus) provided evidence that this species of the Cervidae, like carnivores, lagomorphs and certain members of the Bovidae, possesses a zygomatic salivary gland. Homology of this salivary gland in ruminants and carnivores is assumed on the basis of its over-all topographic position and the number and course of its excretory ducts. The zygomatic gland of roe deer is a polystomatic gland and amounts to 0.02% of body weight. As in Saiga tatarica and Capricornis crispus (Bovidae), its secretions are predominantly serous. Its slightly alterated position in roe deer (and in bovids) seems to be caused by an evolutionary transformation of orbitotemporal proportions and the formation of a lacrimal bulla, in particular. This is an inflation of the intraorbital portion of the lacrimal bone providing ventral support to the ocular bulb. The lacrimal bulla is a late evolved character and emerges late in ontogeny. Its postnatal development in roe deer is presented. Comparison with the neonatal stage of lacrimal morphology in cattle suggests a similar ontogenetic development in the Bovidae. The adult grysbok (Raphicerus melanotis, Neotraginae, Bovidae) provides a ‘model situation’ of the primitive character state at the beginning of the evolutionary development of a lacrimal bulla. Zygomatic gland, lacrimal bulla and other structural elements of the ruminant orbitotemporal region provide an example of the interlocked evolutionary transformation of a complex system, the morphological result of which is a multi-layered compromise between several structurofunctional constraints.
Within the Sabellida, Serpulidae and Sabellidae are sister groups and possess uncini, which are aligned in a transverse row inside the neuropodial rim of the thorax and the notopodial rim of the abdomen. In several sabellid species the shaft (manubrium) of thoracic neurochaetae is much longer than that of abdominal notochaetae. In order to compare both kinds of chaetae and to find hypotheses on the chaetation in the ground pattern of the Sabellidae, structure and development of thoracic and abdominal uncini of the small sabellid Fabricia stellaris were studied ultrastructurally and compared with SEM studies of the sabellids Branchiomma bombyx, Euchone analis and Sabella spallanzani, and the serpulids Protula tubularia and Pomatoceros triqueter. The thoracic uncini of F. stellaris consist of a large rostrum, which is surmounted by several spines of the capitium. Rostrum and capitium are bent towards the manubrium. The chaetae are formed at the dorsal edge of the neuropodial rim, close to the notopodial group of capillary chaetae. A group of microvilli preforms the rostrum, while individual microvilli give rise to each spine of the capitium. During chaetogenesis re-orientation of the microvilli causes curvation of the rostrum and capitial spines. The abdominal uncini have no rostrum. At the begining of their chaetogenesis several individual microvilli form the spines of the capitium. Their characteristic curvature also results from re-orientation of the microvilli during chaetogenesis. A comparison within the Sabellida leads to the assumption that reduction of the rostrum in abdominal uncini occured in the stem lineage of the Fabriciinae, because Sabellinae, Caobangia and Serpulidae retain the plesiomorphic uncinal design with rostrum, capitium and a short manubrium. Increase of the manubrial length of thoracic uncini evolved in the stem lineage of the Sabellidae. This result corroborates the assumption that sabellids evolved an elastic, rapidly secreted tube the animals can easily migrate from and thus were able to colonize instable environments.
The larynges (except for the epiglottis) of two adult Mongolian gazelles, one male and one female, were dissected. This species is characterized by a pronounced sexual dimorphism of the larynx. Dimorphism with regard to the size of the entire larynx and of the thyroid cartilage is about 2:1 whereas the difference of mean body mass is about 1.3:1 between males and females. Unexpectedly, and in contrast to other bovids, the larynx of the male Mongolian gazelle has a paired lateral laryngeal ventricle. However, in contrast to horse, dog, pig and many primate species also possessing such a paired ventricle, its rostral opening in the Mongolian gazelle is situated lateral to the corniculate process of the arytenoid cartilage. The neck of the laryngeal ventricle is embraced by the bifurcated cuneiform process of the epiglottis. Despite the enlarged laryngeal cartilages, the vocal process of the male arytenoid cartilage is relatively shorter than that of the female. The male thyroarytenoid muscle is clearly separated into a rostral ventricular muscle and a caudal vocal muscle whereas the female's, as in other bovids, is almost uniform. The lateral sac of the two-chambered laryngeal ventricle in the male projects laterally between the ventricular and the vocal muscle. As in the domestic bovids and in many other artiodactyls the larynx of the male Mongolian gazelle is lacking any rostrally directed membraneous portion of the vocal fold. Instead, the thick and tough bow-like vocal fold projects caudally into the infraglottic cavity and is supported by a peculiar pan-like fibroelastic pad. This resilient element, situated medial to the bipartite thyroarytenoid muscle, might be a homologue of the vocal ligament, eventually including lateral portions of the elastic cone. A fibroelastic pad is absent in the female. The resilient floor of the laryngeal vestibulum, ventral to the fibroelastic pad, is rostrally and caudally subducted by tube-like spaces. Evolutionary enlargement of the male larynx, including the vocal folds, and of the caudal portions of the vocal tract may have shifted the fundamental and formant frequencies to a lower register. The paired lateral laryngeal ventricle might produce an amplitude increase of the vocalizations assisted by differential action of the bipartite thyroarytenoid muscle. In addition, the peculiar shape, size and tough consistency of the male vocal folds may, as in roaring felids, assist in producing high amplitude and low frequency vocalizations. Perhaps the biological role of the enlarged male larynx of Procapra gutturosa has evolved in relation to its mating system. In the rutting season, dominant males establish individual territories and maintain harems. During prolonged courtship prior to mating, these males perform an acoustic display uttering loud and guttural bellows. In addition, the bulging ventral neck region of males may serve as an optical attractant for the females. Thus, the evolution of the enlarged larynx of the male Mongolian gazelle may have been favoured by sexual selection.
The names Glomeris guttata and G. connexa are each used for at least two different taxa, all of which show a dorsal colour pattern of four rows of light spots on a dark ground. We use allozyme and literature studies to document that the name G. guttata Risso, 1826, can only be applied to a species that is endemic to the Var Valley in Southern France, while G. connexa C. L. Koch, 1847, must be used for the species which has a disjunct distribution in Silesia, Bavaria, Savoy and from the Southern Alps to the Apennines. Based on allozyme data, G. guttata proved to be closely related to G. valesiaca Rothenbühler, 1899, that is distributed from Western Switzerland along the Alps to Provence. G. tetrasticha Brandt, 1833, is the valid name for the species that was erroneously called G. connexa in the literature; G. tetrasticha is distributed from Eastern Europe over Germany to Switzerland. G. connexa C. L. Koch is clearly separated by its colour pattern from the other three taxa. A separate position is also supported by the allozyme data. Furthermore, we show that G. tetrasticha, which is morphologically similar to the northern populations of G. valesiaca, is clearly differentiated from G. valesiaca and from G. guttata according to the genetic data. A key to the identification of the species, distribution maps and figures with specific colour patterns are presented.
The genus Obelus, so far known from shells only, is re-described on the basis of the anatomy of its genital system. Its range is here restricted to north-western Africa and the Canary Islands. Four species are traditionally listed for the Canary Islands: Obelus despreauxii, O. moderatus, O. mirandae and O. cyclodon. The presence of the last species on the Canary Islands is doubtful, whereas the fossil/subfossil presence of O. pumilio is documented. The species Helix morata also belongs to the genus, as well as a new species, O. discogranulatus sp. nov. The genital systems of all confirmed extant Canarian species are shown. Obelus has a peculiar vaginal stimulator appendix (“appendicula”) which is homologous to the penial appendix of the Orthurethra and to the stimulatory organ of other Stylommatophora, with the exception that the A3 portion is missing. The genus is diagnosed by characters of the vaginal stimulator appendix, such as a curved, finger-like A2 portion of the appendicula ending proximally in a blind, well-developed muscular sac, and by the slender tubular A4 portion arising laterally from the muscular sac duct. We conclude that Obelus belongs to the Cochlicella group because it shares an appendicula with the other genera of the group. However, it differs in anatomical details of this structure. The Cochlicella group should be recognized as a separate family Cochlicellidae Schileyko, 1972, with close relationships to the Helicellidae and the Hygromiidae. A new diagnosis for Cochlicellidae is proposed and its phylogenetic relationships are discussed.This is: Notes on the Malacofauna of the Canary Islands, No. 46.
Class Bdelloidea of phylum Rotifera comprises aquatic microinvertebrates that are known for both obligate parthenogenesis and for resisting desiccation through a dormant reversible state. In the frame of an investigation about the role of the nervous system in controlling life cycle, reproduction and dormancy, we describe the serotonergic system of a bdelloid, Macrotrachela quadricornifera, using serotonin immunohistochemistry and confocal laser scanning microscopy. Serotonin immunoreactivity is present in the cerebral ganglion, lateral nerve cords and peripheral neurites. The cerebral ganglion consists of perikarya that send neurites cephalically to the rostrum and corona. A pair of neurites exits the cerebral ganglion as lateral nerve cords, and proceeds caudally to the pedal ganglion where additional neurites enter the foot. Based on the location of serotonergic immunoreactivity, we hypothesize that the neurotransmitter is involved in both motor activity (e.g., ciliary beating, inchworm-like locomotion) and sensory activity. A comparison between the serotonergic nervous systems of M. quadricornifera and species of Monogononta reveals differences in the numbers and patterns of cerebral perikarya, peripheral perikarya, and periperhal neurites. These differences may have functional significance for understanding adaptations to specific environments and/or systematic significance for reconstructing the rotiferan ground pattern.
The monogonont rotifer Bryceella stylata was investigated with light, electron and confocal laser scanning (CLSM) microscopy to provide detailed insights into its anatomy and new information for future phylogenetic analyses of the group. Results from CLSM and phalloidin staining revealed a total of six paired longitudinal muscles (musculi longitudinales I–VI) and eight circular muscles (musculi circulares I–VIII) as well a complex network of mostly fine visceral muscles. In comparison with other rotifer species that have been investigated so far, B. stylata shares the presence of the circular and longitudinal muscles: musculus longitudinalis ventralis, musculus longitudinalis lateralis inferior, musculus longitudinalis dorsalis, musculus longitudinalis capitis and musculus circumpedalis. However, the species lacks lateral and dorsolateral longitudinal muscles and some circular muscles (e.g., corona sphincter, musculus pars coronalis). With light and electron microscopy, we were able to document the precise number of pseudosegments and the arrangement of the chambers comprising the trophi elements. Furthermore, our observations revealed several new morphological characteristics, including a shield-like epidermal projection covering the dorsal antenna, an epidermal projection restricting the corona caudally and an unpaired hypopharynx with distinct shovel-like structures.
Aeolosomatidae and Potamodrilidae are small meiofauna annelids of apparently simple organization and uncertain phylogenetic position. Potamodrilidae was regarded either as a subtaxon of Aeolosomatidae, united with them as Aphanoneura, or entirely unrelated to Aeolosomatidae. Moreover, the groups have been placed in various positions within Annelida: as sister group of Clitellata, as a highly derived clitellate taxon, or excluded from Clitellata and not closely related to them due to great morphological differences. Although molecular studies give strong support for the exclusion of these two taxa from Clitellata their questionable sister group relationship to each other has not been addressed specifically. In the present study sequences of the nuclear 18S rDNA and the mitochondrial Cytochrome Oxidase I gene were used for addressing this question. In addition to the available nuclear 18S rDNA sequences, partial sequences of Cytochrome Oxidase I of Rheomorpha neiswestnovae (Lastochkin, 1935) and Potamodrilus fluviatilis Lastochkin, 1935 along with other polychaete taxa were determined. Combined analyses of these two genes were conducted using Maximum Parsimony and Bayesian analysis. A sister group relationship of Aeolosomatidae and Potamodrilidae is significantly supported in all. As in previous studies a relationship to Clitellata is not supported but the phylogenetic position of both Aeolosomatidae and Clitellata within the polychaetes remains enigmatic.
Morphology and systematics of the rotifer genus Pseudoploesoma Myers, 1938 are discussed. The genus is transferred from Synchaetidae to Notommatidae. One species, P. formosum (Myers, 1934), is recognized. Pseudoploesoma greeni Koste, 1978 probably belongs to Notommata but must be considered incertae sedis and species inquirenda on account of its poor description; P. greeni sensu Coussement and Dumont (1980) is identified as Notommata copeus Ehrenberg, 1834. (c) 2007 Elsevier GmbH. All rights reserved.
Courtship, mating and spermatophores of Phrynichus exophthalmus and P. deflersi arabicus nov. ssp. are described. Courtship of P. exophthalmus is more complex than in other amblypygids, with close contact between mates nearly throughout the mating dance. After spermatophore formation, the female is lured to the spermatophore and then firmly pressed onto it. Mating behaviour and spermatophore confirm the placement of this species in the Phrynichus ceylonicus group and show that the similarities with Euphrynichus, like long and thin pedipalps with bacilliform apophyses instead of spines, are the result of convergent evolution. Courtship of P. d. arabicus is conservative, similar to that of P. dhofarensis and many other amblypygids. After spermatophore formation, the female is lured to the spermatophore, then pulled over and pressed onto it. The results suggest that the P. ceylonicus group and the P. deflersi group and sister groups, but the low number of investigated species precludes a definite conclusion.
The freshwater rotifer, Filinia novaezealandiae, is a planktonic species in tropical limnetic ecosystems. Like other species in the genus, F. novaezealandiae has two mobile, anterolateral setae that supposedly facilitate saltation through the water column as a means of escape from predators. However, very little is known about setal structure or the control of setal movement. Here, we use a combination of behavioral observations, scanning and transmission electron microscopy, phalloidin staining of F-actin, conventional fluorescence and confocal laser scanning microscopy, and three-dimensional (3D) analysis software to investigate saltation in F. novaezealandiae and gain insight into the contribution that both setae and muscles play in locomotion. Results from EM reveal that the paired anterolateral setae are smooth, hollow extensions of the syncytial integument and constructed of two layers: a thin internal and thick external lamina. The setal cavity is continuous with the body cavity of the trunk, and the setae articulate with the trunk at a series of flexible folds. A lack of direct muscular supply to the setae indicates that their movement is likely to result from a combination of: (1) contractions of specific muscle sets (e.g., anterior transverse muscle, post coronal ring muscle) that insert on the body wall around the setae; and (2) changes in hydrostatic pressure within the body cavity that accompany coronal withdrawal (via contraction of retractor muscles) and extension. These descriptions, together with behavioral observations, indicate that the primary function of the setae is likely to be predator deterrence and not predator evasion. Likewise, saltation is probably a result of heightened coronal activity that immediately follows cycles of setal abduction/adduction. These insights, together with new descriptions of the muscular system in F. novaezealandiae, may be of utility in understanding the evolution of locomotory mechanisms among rotifers.
Biochemical and ultrastructural advances in the latter part of the 20th C. have revolutionized our understanding of cryptobiosis since Anton van Leeuwenhoek gave the first formal description of the phenomenon at a Royal Society lecture in 1702. Keilin coined the term cryptobiosis in 1959 to describe the entry into a reversible ametabolic state and recognized that such ‘latent life’ could encompass processes induced by dehydration, cooling, and perhaps osmotic stress and anoxia. True cryptobiosis, as now understood, depends on the loss of a liquid water phase and can be induced by desiccation or freezing. Loss of ‘bulk’ or liquid water may result directly from evaporation, or arise through vitrification promoted by the formation of a carbohydrate matrix. The carbohydrates in question appear to be ubiquitous in cryptobiotes and serve multiple additional roles: as compatible intracellular osmolytes during desiccation or freeze-dehydration; as stabilizers of protein quaternary structure and lipid bilayer integrity with declining free water activity; and as supercoolants. Plants tend to rely on oligosaccharides such as stachyose and raffinose, while yeasts, spores, and metazoans depend primarily on disaccharides, particularly sucrose and trehalose, and on glycerol. As in many other anhydrobiotes, a metabolic preparatory stage in which these carbohydrates are synthesized from glycogen reserves appears essential for anhydrobiosis in tardigrades, and thus limits physiological tolerance of desiccation rate. Adaptive processes such as tun-formation in tardigrades and bdelloids, coiling in nematodes, and gradient-dependent changes in integumental permeability, retard water losses during preliminary desiccation and exert important influence on survival in xeric extremes. In tardigrades, cryobiosis, or cold-induced cryptobiosis, differs from anhydrobiosis in several important details. Tun formation is not essential for survival, and tolerance of cooling rate depends on the ability to inhibit intracellular freezing. Unlike many cold-tolerant arthropods, tardigrades are freeze-tolerant. Extracellular freezing is promoted by one or more ice-nucleating proteins in Adorybiotus coronifer, and occurs at high temperatures close to 0 °C. Tolerance of variable cooling rates to sub-freezing temperatures in this species does not seem to depend on trehalose synthesis, although a role of other possible intracellular cryoprotectants is likely. It is presently unclear whether cryobiotic tardigrades undergo cytoplasmic vitrification, or whether freeze-dehydration and colligative lowering of cytoplasmic water activity renders the remaining water unfreezable. The profound tolerance of environmental extremes displayed by cryptobiotic organisms apparently depends on the loss of a liquid water phase with accompanying metabolic depression as elegantly described by Clegg's vicinal network model. Thus protected from temperature- and solute-dependent effects on reaction kinetics, and (in part) from destructive free-radical oxidation, cryptobiotes can retain viability in a near-inert state for decades. Disruption of multi-subunit enzyme reactions accompanying loss of the vicinal water fraction may control the decline in metabolism, but also eliminates important free-radical scavenging pathways. Glycerol partly offsets this, acting as an antioxidant, but progressive free-radical oxidation in cryptobiotes may set the upper limit to longevity under aerobic conditions. While we can make many inferences of the physiology of cryptobiosis in tardigrades based on information gathered from other cryptobiotic organisms, specific studies on tardigrades are few, and encompass only a small number of species. This should prove a fruitful field for future research.
Mr. Chairman. Distinguished ladies and gentlemen. As Dean of Science it is a great honour on behalf of the University of Copenhagen and the Faculty of Science to welcome all of you here to the 8th International Symposium on Tardigrada. We are especially happy to have you here at the August Krogh Institute (named after our well-known Nobel Prize winner in Physiology), because on September 1st we celebrate the establishment of the Faculty. So coming here and honouring our 150 year anniversary jubilee help us to promote the importance of science in our society. The University was founded in 1479 as a theological catholic school. It broke down in 1530 and was reestablished in 1537 after the reformation. Right from the start in 1479 there was science thought of at the university. Mathematics and Astronomy. And Zoology became a subject over the centuries together with other subjects which are today regarded as science. But only in 1850 did we become an independent Faculty thanks to the effort and progress done by the Danish Chemist H.C. Ørsted.
The oribatid mite Scutovertex pileatus sp. nov. is described on the basis of adult individuals originating from southern Austria (Carinthia). The new species shows the typical habitus of Scutovertex and is distinguished by the cerotegument and cuticle forming irregular nodules and bars over the entire body; the rostrum with two visor-like projections, with the ventral projection larger and arched ventrally; short lamellar setae; two pairs of converging ridges between the lamellae; small notogastral setae that are not broadened distally; and a sclerotized rib across the mentum. Furthermore, DNA sequences of the COI gene (region 2, 567 bp) of S. pileatus were compared with those of S. minutus, S. sculptus, using Cymbaeremaeus cymba as the outgroup. Molecular data unambiguously support the discreteness of all three species by placing them reciprocally monophyletic, as well as by large genetic divergences. Interspecific distances among C. cymba, S. minutus, S. pileatus and S. sculptus amounted to 13.7–29.9%.
Two new water mite species of the genus Hygrobates Koch, 1837 (Acari, Hydrachnidia, Hygrobatidae) were found to live parasitic on newts of the genus Paramesotriton Chang, 1935 (Amphibia, Caudata, Salamandridae) from Vietnam and Laos: Hygrobates forcipifer sp. nov. and H. ancistrophorus sp. nov. The H. salamandrarum-group is defined, that now includes three species from Southeast Asia. Males and females of both new species are described, as well as larvae and deutonymphs of the Vietnamese species. These data provide the first record of males, nymphs and larvae of the species-group. The systematic position of the group, as well as the parasite–host association and the lifecycle of the species are discussed. Furthermore, the character states of the striking mouthparts, particularly modified as an adaptation for penetrating the amphibian skin, the genital skeleton and the larval morphology are examined.
The position of the family Myobiidae in the infraorder Eleutherengona (Prostigmata) was analyzed with a cladistic parsimony approach for the first time. Species of the genera Anystis von Heyden (Anystidae), Pomerantzia Baker (Pomerantziidae), and Walytydeus Kuznetzov (Paratydeidae) were selected as outgroups. Among Eleutherengona, species of the following genera were selected as ingroup taxa: Hirstiella Berlese (Pterygosomatidae), Eucheyletia Baker, Cheyletiella Canestrini (Cheyletidae), Syringophilus Heller (Syringophilidae), Tarsocheylus Berlese (Tarsocheylidae), Heterocheylus Lombardini (Heterocheylidae), Pygmephorus Kramer (Pygmephoridae), Raphignathus Dugès (Raphignathidae), Neognathus Willmann (Caligonellidae), Storchia Oudemans (Stigmaeidae), and Tuckerella Womersley (Tuckerellidae). Three most parsimonious trees with similar topology were obtained. In all these trees, the family Myobiidae is situated outside of the clade joining the higher Raphignathae (Raphignathoidea and Cheyletoidea) and represents a branch within the earlier derivative Raphignathae. This result is based primarily on characters from leg setation and postembryonic development. The conclusion from this topology is that myobiid mites have developed some gnathosomal structures convergently with Cheyletoidea, including the stylet-like chelicerae and stylophore fused with the subcapitulum. The evolution of animal eleutherengone parasitism is discussed. Parasitism arisen independently in numerous phyletic lineages or superfamilies of Eleutherengona. The representatives of some phylogenetically distant eleutherengone lineages developed similar adaptations to predation and parasitism. However, in spite of some similarities in these adaptations, the evolutionary trends and pathways for switching to a parasitic mode of life are quite different in particular eleutherengone lineages.
Many papers describe the cnidae from acontiarian sea anemone species, but comparative studies involving significant data amounts, combined with adequate statistical treatment have not been realized. The aim of the present paper is to carry out a comparative study of acontian cnidae from the species Haliplanella lineata (Verrill, 1869), Tricnidactis errans Pires, 1988 (Haliplanellidae) and Anthothoe chilensis (Lesson, 1830) (Sagartiidae). Five living specimens of each species were used; the length of 50 unfired capsules was measured and taken randomly from the following nematocyst categories: b-rhabdoids, p-rhabdoids B1b, p-rhabdoids B2a. A total of 2,000 measurements was done. The data were analyzed with descriptive statistics (mean, standard deviation, median, maximum, minimum, and semiinterquartile range) and Shapiro-Wilks test, Box-Cox transformation, Kruskal-Wallis test and single factor ANOVA. The normal distribution of the dataset must be tested for each nematocyst type in any quantitative study of the cnidae. We conclude that variation in nematocyst size should not be used as an element of conclusive value in the diagnosis of species of acontiarian sea anemones. For these purposes, other characters have to be used to define precisely each taxon, including qualitative variation of the cnidae.
Interest in parasitoids has grown with the recognition that host-parasitoid systems offer opportunities to examine fundamental questions in behavioural and evolutionary ecology. Tachinid flies of the Ormiini possess a conspicuously inflated prosternal region, enabling them to detect the mating songs of their hosts. This speciality makes them a highly suitable group for studies of adaptive radiation. To emphasise further research in this important group of parasitoids, their biogeography and host species are summarised.The Ormiini are a particularly small group, containing only 68 described species of predominantly tropical, especially neotropical forms. A table of host-parasitoid relations reveals that predominant parasitism is of bushcrickets. The exploitation of cricket songs appears to be a derived pattern that evolved as a host switch some time after the Eocene.Hypotheses concerning fly-host coevolution and the reasons for the development of hearing are discussed, and include the question of mate finding and avoidance of bats as predators.
We used SEM to investigate the morphology of the cypris larvae from a range of species of the Cirripedia Acrothoracica, representing all three families and including the first detailed account of cyprids in the highly specialized Cryptophialidae. Special attention was given to the head shield (carapace), the lattice organs, the antennules, the thoracopods, the telson and the furcal rami. The cypris larvae of the Acrothoracica fall into two morphological groups; those of the Trypetesidae and Lithoglyptidae have a well-developed carapace (head shield) that can completely enclose the body and sports fronto-lateral pores, numerous short setae and lattice organs perforated by numerous small, rounded pores and a single, conspicuous terminal pore. The fourth antennular segment has the setae arranged in subterminal and terminal groups. There is a developed thorax with natatory thoracopods and a distinct abdomen and telson. In comparison, the cyprids of the Cryptophialidae exhibit apomorphies in the morphology of the carapace, the antennules and the thorax, mostly in the form of simplifications and reductions. They have a much smaller head shield, leaving parts of the body directly exposed. The shield is conspicuously ornamented by deep pits and hexagonally arranged ridges and bears a few, very long setae but lacks fronto-lateral pores. The lattice organs have numerous elongated pores, but no large, terminal pore. The fourth antennular segment has all the setae clustered in one terminal group. The thorax and thoracopods are rudimentary and not suitable for swimming. These reductions and simplifications in morphology correlate with cryptophialid cyprids being unable to swim. They can only disperse by antennular walking resulting in small, but highly gregarious populations of adults. The variations in antennular morphology and telson structure were traced for the genera of the families Lithoglyptidae and Trypetesidae. The traditional non-cladistic taxonomy in the suborders Pygophora (Cryptophialidae+Lithoglyptidae) and Apygophora (Trypetesidae) was based largely on symplesiomorphies in adult morphology and cannot be upheld. The Lithoglyptidae and Trypetesidae may form a monophylum, but evidence remains scarce. We expect that the use of larval (cyprid) characters will in the future play an important part in more detailed phylogenetic analyses of the Acrothoracica and also shed new light on their reproductive ecology.
The external morphology of the dwarf males of Lithoglyptes mitis, Lithoglyptes bicornis, Kochlorine hamata, Kochlorine sp., Cryptophialus hoegi, Cryptophialus sp., and Trypetesa lampas was examined under SEM. New data on the cuticular structures are compared with existing information on acrothoracican and thoracican males. The structure of the male mantle differs among acrothoracican families and thus may have taxonomic value.
The phenotypic consequences in the house mouse (Mus musculus domesticus) of the transition from an ordinary field-dwelling rodent to a species that is dependent on human populations was studied by investigating the morphometric variation of non-commensal populations of M. m. domesticus from Syria, Jordan, SW Iran, and Libya and comparing them with that of conspecific commensal populations from Eastern Turkey, Greece, and Bulgaria. Commensal populations of M. musculus musculus from the Czech Republic were used as an outgroup. About 849 adult specimens of M. musculus were analysed by multivariate procedures based on standard molar, skull and body measurements. As expected, there was considerable variation among the studied populations and a good correspondence between morphometric and geographic distances. The resulting morphometric tree was consistent with the hypothesis that the original radiation of M. m. domesticus took place somewhere in the Near East. Commensal populations of M. m. domesticus form a single derived branch. Specimens originating from four different sites in eastern Syria showed the greatest similarity to one another and possessed relatively bigger molars than the other studied populations. Commensal populations were characterised by longer tails when compared to non-commensal populations, which suggests an adaptation for living in a more three-dimensionally heterogeneous environment for commensal populations.
Drakensbergianella rudebecki, a new genus and new species of flea beetle (Chrysomelidae, Alticinae) found at high elevations from Southern Africa (Drakensberg mountains) is described. This new genus is closely related to the genus Gabonia Jacoby, 1893 but is easily distinguishable mainly by: the metasternum shorter than the length of the middle coxal cavities; the legs with femora and tibiae clearly elongate, especially the hind ones; the antennae generally longer than body in both sexes, especially in males; the metafemoral spring with inner side of the ventral lobe not angled; the metathoracic wings strongly reduced. Line drawings of male and female genitalia, metafemoral springs, and scanning electronic micrographs of particular morphological aspects of the taxa considered are provided. Finally, a brief discussion about Gabonia and related genera in the Afrotropical region with a key for the identification, is also reported. Moreover, the following new combination is proposed: Longitarsus ruandensis Weise, 1910 = Montiaphthona ruandensis Weise, 1910 n. comb.
This paper describes courtship behaviour, spermatophore morphology, and the female genitalia of the African whip spiders Charinus africanus Hansen, 1921 (Charinidae) and Damon tibialis (Simon, 1876) (Phrynichidae). In C. africanus, only the first part of courtship behaviour, up to spermatophore formation, could be observed; though different in detail, it is similar to that of many other species. The small spermatophore of C. africanus contains one large median sperm package. Charinus africanus is one of the Charinus species with thin finger-like gonopods and the first species with such gonopods of which the spermatophore is known. Spermatophores and female genitalia of D. tibialis are similar, though different in details, to those of Trichodamon and Musicodamon. They thus suggest that these two genera are correctly included in the Damoninae.
A seasonal survey of tardigrade populations in the riparian zone of the Choccolocco Creek, Alabama, was undertaken from August 1994 through December 1995. Six sites within the riparian zone were sampled in different portions of the creek. At each site, 3 trees with cryptogams were sampled six times during survey period. From a total of 108 samples, 1,588 tardigrades were extracted and individually mounted on slides in Hoyer's medium. The community was dominated (86%) by specimens in the genus Macrobiotus. One species of Echiniscus was new to science and will be described in a separate paper. No significant difference was found between tardigrade occurrence (total number of individuals) and season, moss genera, or tree species. However, there was a significant relationship between the number of tardigrades and site, indicating the need for additional replicate samples. Simpson's and Shannon-Wiener's species diversity indices indicated that species richness and evenness were low. Jaccard's and Standard's community similarity indices suggested that the communities within the riparian zone were dissimilar along Choccolocco Creek.
Reproductive biology and spermatophore morphology of four species of Amblypygi, belonging to two different families, are described. Basically, courtship and mating in Sarax buxtoni, S. brachydactylus, Stygophrynus brevispina nov. spec. and Charon cf.grayi are similar to those of many other whip spiders. However, each species has its own peculiarity. Like in other species, the female is not passive during courtship; she plays an active role with her own courtship signals and may even initiate courtship behaviour. The comparison of the spermatophores of S. buxtoni and S. sarawakensis with S. brachydactylus show two different types of spermatophores. At present, all three species should be included in the same taxon and Phrynichosarax should be considered a junior synonym of Sarax as long as there are no synapomorphies known. Mating behaviour and spermatophore morphology of C. cf.grayi from two different localities suggest both represent different species. Their behaviour and spermatophores and that of Stygophrynus brevispina supports the placement of the genera Stygophrynus and Charon in the taxon Charontidae. The presence of lateral horns on the spermatophore head of Charon raises the question of whether these structures are synapomorphic for the Neoamblypygi or even Euamblypygi. This question cannot be answered conclusively at present.
Specimens of the marine tanaid crustacea Halmyrapseudes spaansi, sampled in temporary littoral muddy patches near the mouth of the Kaw river (French Guiana, SE America), showed protozoan epibionts herein described as a new species: Cothurnia guyanensis sp. n. (Ciliophora, Peritrichia). These ciliates were covered by a cylindrical or bell-shaped lorica containing an oval elongated zooid with a rounded contractile vacuole located anteriorly in lateral position. The macronucleus was “S” shaped. The peristomial disk was anterior and included a polikinety and a haplokinety. The external stalk was short and broad, with 8–18 longitudinal conspicuous striations. Between the external stalk and the zooid, there were an endostyle and an mesostyle both short and broad. The striations of the external stalk were prolonged in the mesostyle. Telotroch stages were observed and described, as well as specimens with two zooids per lorica. Epibionts located on the ventral area, pereopods and antennae of the basibiont.
During July 1999, a study group from the University of Kansas visited the ancient Inca ruins in and around Machu Picchu and Ollantaytambo, Peru. They collected lichens and mosses from the rock walls around the ruins. The samples contained four genera and six species of tardigrades. No associational patterns and relationships were detected. A new species, Echiniscus ollantaytamboensis nov. sp. is described.
Viviparity (i.e., the bearing of live young) has evolved from oviparity (egg laying) independently in various major vertebrate lineages, and several transitional stages have been described. The transition from oviparity to viviparity requires the retention of fertilised eggs in the female reproductive tract. Caecilian amphibians (Gymnophiona) display a considerable diversity of reproductive modes, including oviparity and viviparity. Among amphibians, caecilians have also modified the process of internal fertilisation through a special intromittent organ, or phallus, in males. Here we report the oviposition of “embryonated” eggs ranging from various gastrula-to-neurula stages by female Ichthyophis cf. kohtaoensis (Ichthyophiidae) from North-eastern Thailand. In addition, we describe a copulation resulting in an oviposition of embryonated eggs. Our findings will have implications for the further understanding of the evolutionary reproductive biology of amphibians.
We report a study on anhydrobiotic survival in the eutardigrades Richtersius coronifer and Ramazzottius oberhaeuseri. In each of these species, we investigated the anhydrobiotic survival of two populations, one from Sweden and one from Italy. We found that anhydrobiotic survival was similar in the Swedish and the Italian populations in both species, indicating no divergence with respect to anhydrobiotic capacity. Body size had a strong effect on the probability to recover from anhydrobiosis, but the effect was in opposite direction in the two tardigrade species. Ramazzottius oberhaeuseri had a considerable higher overall survival (66%) than R. coronifer (40%). This result is in line with earlier studies that found R. oberhaeuseri to have a very high water-retentive capacity.
Tardigrades are well known for their capacity to enter an anhydrobiotic state, and remain ametabolic for several years. Yet the evolutionary background, and the forces of natural selection that act on anhydrobiotic capacity have remained unexplored. In this paper, I review the basic problem of anhydrobiosis and the phenotypic traits that may be the main targets of natural selection for improved anhydrobiotic capacity. I also make an attempt to put anhydrobiosis into a life history perspective, and discuss this life form in the perspective of energetic and genetic constraints.
Age, body size, and growth patterns in the subtropical anuran Hyla annectans chuanxiensis from high (Dengchigou Protection Station) and low (Lingguan Town) elevations in Baoxing County of Sichuan province (China) were described using skeletochronology. Females were significantly older than males at the low-elevation site, but there was no significant difference between the sexes at the high-elevation site. Age at sexual maturity of both males and females was 2 years at the high-elevation site, whereas males matured at 1 year and females at 2 years at the low-elevation site. Males and females from the low-elevation population reached a maximum age of 3 and 4 years, respectively, whereas males and females from the high-elevation population reached a maximum age of 4 and 5 years, respectively. At both sites, females were significantly larger than males. Females and males from the high-elevation population were larger than individuals from the low-elevation population. When the effect of age was controlled, the differences in body size of the two populations were significant only for females. Von Bertalanffy growth curves indicated that the growth rates in males was greater than in females in both populations. They also showed that the growth of both sexes slowed at an earlier age in the low-elevation population than in the high-elevation population. The findings suggest that age is a major factor underlying body size patterns for both sexes, but that the elevation of the locality affects the body size of females.
The Chrysopetalidae are a small taxon of polychaetous Annelida with a controversial position in the phylogenetic system. Although they most likely belong to the Phyllodocida, their position is difficult to infer because they share some characters with most taxa of this group. Little information is available about the internal anatomy of the Chrysopetalidae. In order to provide additional data for clarifying the systematic position of the group, we here describe the structure of the body wall, coelomic organization, nephridia, oogenesis, spermatozoa and copulatory organs in four species. The Chrysopetalidae comprise a group of relatively large, epibenthic shallow-water species and a group of small endobenthic forms; two representatives of each group have been chosen, two Chrysopetalum spp. and two Dysponetus spp. All species have comparatively short segments, no circular body wall muscles, a highly developed system of transverse, oblique, dorsoventral and parapodial muscles, metanephridia and a closed circulatory system without a heart. Spermatozoa of the primitive type and gonochorism were observed in both Chrysopetalum species, whereas Dysponetus pygmaeus is a protandric hermaphrodite possessing filiform spermatozoa showing mitochondrial interpolation and male copulatory organs. These features of the reproductive system and a relatively simple organization of the other structures investigated are regarded as apomorphies and adaptations typical of meiobenthic polychaetes. The results of the present investigation are indicative of a fairly basal position of the Chrysopetalidae within the Phyllodocida.
The ultrastructural study on the fat body of gynes (virgin queens) of the basal ant species Cyphomyrmex rimosus and Mycetarotes parallelus and the derived Acromyrmex disciger and Atta laevigata queens showed vesicular rough endoplasmic reticulum, Golgi complex, and mitochondria in trophocytes, suggesting the involvement of these cells in protein synthesis, in addition to digestive vacuoles associated with the digestion of endocytosed compounds or rejected cell organelles. Oenocytes, another cell type present in the fat body of these species exhibit mitochondria, digestive vacuoles, and vesicles, indicating a mobilization of compounds by these cells. In A. laevigata, oenocytes also exhibited large storage sites of glycogen, in addition to a well-developed vesicular rough endoplasmic reticulum, suggesting an intensive participation of these cells in protein synthesis. The ultrastructural cytochemistry study also revealed electrodense granules of basic proteins present throughout the cytoplasm of trophocytes. The same was observed in oenocytes, although with smaller amounts of proteins. In the cytoplasm of trophocytes and oenocytes were also found droplets or electrodense granules of lipids. In oenocytes of A. disciger and in trophocytes of A. laevigata, lipids were observed in mitochondria, suggesting that this organelle might be a site of synthesis of these compounds. The chemical analysis of lipids revealed that in gynes, the main compounds present in fat body cells were saturated fatty acids, while in queens, saturated as well as unsaturated fatty acids were found. In conclusion, the present study showed that the fat body cells of gynes and queens, in general, maintained the same compounds and original features through the evolution process of the Attini tribe.
The species belonging to the subfamily Phyllomedusinae presents physiological and behavioral adaptations to economise water such as secretion of lipids coupled with its spreading onto the skin surface through a complex behavior, adoption of diurnal torpor and secretion of uric acid. Here we describe other adaptation probably involved with water economy, registered in Phyllomedusa distincta, P. tarsius, P. tetraploidea and natural hybrids of P. distincta and P. tetraploidea — at dusk, these amphibians perform an elaborate moulting behavior that encompasses the cleaning of the body with the limbs plus gaping and body contractions. Our data show the daily moulting in P. distincta and suggest that the same mechanism occurs for the other species studied. We suppose that daily moulting improves the skin permeability to water being a characteristic of the phyllomedusines which spread lipids onto the skin surface.
A review of species in the genus Praon Haliday, 1833 is presented. Twenty described species are keyed and illustrated with scanning electron micrographs and line drawings. The Praon species presented in this work have been identified from 67 aphid taxa occurring on 120 plant taxa. Furthermore, 87 original parasitoid–aphid–plant associations of the species mentioned in the key are presented. Phylogenetic relationships among Praon species are reconstructed using parsimony and cladistic distance methods. Praon abjectum is the sister taxon to the remaining Praon species. We recognized three species group: “Parapraon”, “dorsale-yomenae” and “rosaecola”. Monophyly is suggested for “Parapraon” species group and paraphyly for “dorsale-yomenae” group. Finally, by phylogenetic reconstruction, a close phylogenetic relationship between “Parapraon” and “dorsale-yomenae” species group was found.
The buccopharyngeal apparatus of several species of tardigrades, including both heterotardigrades and eutardigrades, has been prepared for scanning electron microscopy (SEM) by using a new method developed and refined for this purpose. The buccalpharyngeal apparatus from three well-known species are described in detail and preliminary attempts to interpret the function of some of the structures are presented. The chosen species are used as examples and the new findings are compared to studies from the literature. The species used are: Echiniscoides sigismundi, Halobiotus crispae and Milnesium tardigradum. A redescription of the buccopharyngeal apparatus, in particular the stylets, the stylet supports, the stylet sheaths and their interrelationships, is presented for each species. For H. crispae the cuticular elements of the pharynx are also redescribed from this material. The potential for new information available with this method is discussed, together with the possible artifacts and difficulties the method may cause.
We tested the hypothesis that skull shape within the genus Mus may vary with geographic location by assessing the extent and spatial distribution of phenotypic skull variation within and among two wild mouse species, M. macedonicus and M. cypriacus, using traditional and geometric morphometrics including a rather novel application of sliding semilandmarks. Shape was shown to be significantly correlated both with longitude and latitude in M. macedonicus, yet the correlation between morphometric and geographic distances was not significant, and morphometric differences between Asian and European populations were not higher than those within the particular continents. The phylogenetic signal was found to be stronger in dental characters than in cranial ones, however, overall concordance between the pattern of morphometric variation and the presumed history of M. macedonicus was rather weak. In both species, the dorsal and ventral sides of the skull were shown to covary in many aspects though there were also some differences between them, making the functional interpretation of these differences difficult. Discrimination between M. cypriacus and M. macedonicus as well as discrimination between two M. macedonicus subspecies was highly reliable using both traditional and geometric morphometric tools to analyze skull measurements.
Following the first records of Chthonius (Ephippiochthonius) boldorii Beier, 1934 in central Europe, a species which was previously assumed to occur exclusively in Mediterranean caves, 116 series (595 specimens) of the cryptic taxa C. (E.) boldorii and C. (E.) fuscimanus Simon, 1900 (Syn. C. (E.) austriacus Beier, 1931) were re-examined. Although multivariate analyses suggest specific separation, there is only one unequivocal character for discrimination: the presence or absence of a single isolated tooth on the moveable finger of the chelicerae. The distributions were found to be largely allopatric, therefore it is concluded that the species rank of the two morphospecies is justified. North of the Alps, an almost vicariant pattern emerged: east of 14° E fuscimanus occurs, west of this line boldorii occurs. The results provide a basis for discussing the relevance of minute morphological differences in pseudoscorpion taxonomy.
Extensive terrestrial exchanges were initiated by the closure of the Tethyan Seaway during the Early Miocene. Proboscideans are among the most prominent African immigrants, which arrived in Eurasia about 19 Ma ago via the “Gomphotherium Landbridge”. Several distinct waves of continental migrations, however, document that the formation of this landbridge was a multiphase process. Until the closure, a marine faunal exchange was enabled via the Mesopotamian Trough and the Zagros Basin, as reflected by contributions of Indonesian corals in the Iranian basins and by the occurrence of “western” gastropods in Pakistan and India. Nevertheless, the emergence of the landbridge was preceded in the marine biosphere by first biogeographic divergences on both sides of the seaway already during Oligocene times (e.g. within the tridacnines and strombids). Around the closure event, the breakdown of biogeographic relations was near-complete and the Proto-Mediterranean faunas bear little in common with those of the Indo-West Pacific Region (IWPR). Some of the discussed examples suggest that the Western Tethys Region (WTR) had acted as centre of origin and diversity during Oligocene and Early Miocene times. After the closure of the seaway, this centre had shifted to the southeast, heralding the enormous biodiversity of the modern IWPR. Some originally WTR elements managed to follow this shift and formed the Miocene stock for the modern IWPR faunas. In contrast, the marine fauna in the Mediterranean cul-de-sac suffered strong impoverishment due to the Miocene cooling, the Messinian Salinity Crisis and the late Pliocene and Pleistocene glacials – a fact which might explain the receptivity of the Mediterranean Sea for Lessepsian migrants.
Homology between the lacinia mobilis of peracarid crustaceans (Malacostraca) and movable appendages of the mandibular edge in other crustaceans, hexapods, and myriapods has been advocated in classical as well as recent phylogenetic studies, and in some cases this feature has been attributed major significance in arthropod systematics. A comparative SEM survey of the lacinia mobilis in Peracarida and its alleged homologues (prostheca of Hexapoda, internal tooth of Diplopoda, ‘lacinia mobilis’ of Symphyla and Remipedia) rejects the primary homology of these varied structures. The lacinia mobilis of Peracarida can be characterized precisely by asymmetry on the left and right mandibles, as a strong tooth-like structure on the left mandible which is oriented at a right angle to the remaining edge and as a stalked, spine-like structure on the right mandible. A fundamental difference to other Malacostraca is that the peracarid lacinia mobilis characterizes the adult mandibles. Supposed homologues of the peracarid lacinia mobilis are instead a modified pectinate lamella (Diplopoda, Chilognatha) or a movable appendage that is associated with the pars molaris rather than the pars incisivus (Symphyla), or an inner separation of the incisor process (Remipedia). The detailed structure of the prostheca in Campodeoida and Ephemeroptera weakens interpretations of its origin as a separation of the incisor process.
The Cambrian fauna can now reasonably be seen as containing many taxa that lie in the stem-groups of the extant phyla. As such, these fossils suggest how both the ‘body plans’ of extant phyla were assembled, and also how various ‘minor’ phyla relate to the larger groupings of today such as the arthropods and annelids.The various arthropod and lobopod taxa of the Cambrian faunas have been controversial and have generally been considered either as lying in the crown or (occasionally) stem groups of the euarthropods, onychophorans and tardigrades. However, phylogenetic analysis strongly suggests that many of even the most euarthropod-like taxa do not lie within the euarthropod crown-group but are more basal. Further, the commonly expressed view that Cambrian lobopods are in effect stem- or crown-group onychophorans also seems not to be well supported. Lobopods in the Cambrian appear to be diverse and not particularly closely related to one another, and certainly cannot be combined in a monophyletic clade.Both these advances offer hope that the tardigrades (placed as the sister group to the euarthropods in many analyses of extant taxa, here collectively named the Tactopoda) may be more closely related to some of these Cambrian taxa than others. The challenge for both neontologists and palaeontologists is to refine the systematic analysis of both living and fossil taxa in order to maximise the usefulness of the (admittedly few) characters that unite tardigrades to their Cambrian forbears.
Lattice organs are peculiar chemoreceptors found only in the Crustacea Thecostraca (Facetotecta, Ascothoracida, Cirripedia). In these taxa, five pairs occur in the head shield (carapace) of the terminal larval instar (y-cyprid, ascothoracid larva, cyprid), which is the settlement stage. Lattice organs represent an autapomorphy for the Thecostraca but their evolutionary origin and possible homologues in other Crustacea remain obscure. We have used scanning electron microscopy to describe the setation pattern of the head shield in late nauplii of one species of Ascothoracida, one species of Facetotecta and several species of the Cirripedia Thoracica, Acrothoracica, and Rhizocephala. The naupliar head shield always carries two pairs setae situated anteriorly near the midline. Each of these setae carry a single pore, and positional, structural and ontogenetic evidence show that these setae are homologous in all the examined species and that they represent precursors of the two anterior pairs of lattice organs of the succeeding larval stage, viz., the ascothoracid larva (Ascothoracida), y-cyprid (Facetotecta), and cyprid (Cirripedia). This leads us to infer that lattice organs are among the most highly modified sensilla in all Crustacea and they have in most cases lost all external resemblance to a seta. The nauplii of the Rhizocephala carry an additional three pairs of setae situated more posteriorly on the head shield and they could be precursors of the three posterior pairs of lattice organs. All other species examined lack these posterior setae, except the Facetotecta which have one posteriorly situated pair.
Previous approaches to interpret male genital sclerites of Raphidioptera, Megaloptera and Neuroptera (constituting the superorder Neuropterida) have become polarized in the controversy between “archaic derivates and evolutionary novelties”. Arguments for deciphering the homologies via the gonocoxites and their corresponding styli and gonapophyses are presented. Primitive machilid (Archaeognatha) structures provide the basis for identification of the amazingly similar male genital sclerites of Raphidioptera. The comparatively complete segment 9 of Raphidioptera, consisting of tergite, sternite, large gonocoxites, styli and gonapophyses, serves as a model of reference for homologising segments 10 and 11 in Raphidioptera and for interpreting male genital sclerites in Megaloptera and Neuroptera. Existing terminology is inconsistent with respect to homology, therefore names for structures will be applied strictly and redefined according to the hypotheses presented here. No new names will be introduced. The large 9th gonocoxites are modified to appendage-like sclerites in Megaloptera and Neuroptera, while in some Neuroptera they have shifted into the genital chamber or become obliterated. The styli of segment 9 have disappeared independently several times. The 9th gonapophyses have remained rod-like in some Raphidiidae (hypovalva), but are secondarily absent in Megaloptera and most Neuroptera. Sclerites of segment 10 underwent very dramatic changes (and obliterations) with respect to copulation, and the 10th tergite has become amalgamated with tergite 11 to form the terminal ectoproct. All other sclerites have migrated into the genital chamber. The 10th gonocoxites and the 10th gonapophyses evolved into a joint structure, the parameres. The styli of the 10th gonocoxites have fused together to form a median sclerite: the mediuncus. The 11th tergite is part of the ectoproct, the 11th sternite may be present as a tiny relic sclerite, the subanale. The gonarcus is identified as the 11th gonocoxites, the entoprocessus is defined as the 11th gonapophyses, the arcessus represents the (fused) 10th styli. The hypandrium internum, a trident sclerite at the gonopore remains enigmatic as a possible autapomorphy of the Neuropterida.
An analysis of 30 craniological characters of Eurasian badgers (Meles spp.) revealed different levels of sexual size dimorphism (SSD) and geographic variation in the three different species. SSD is displayed mostly in the general size of the skull (condylobasal length, zygomatic width, width of rostrum, and cranial height) and mandible (height of the vertical mandibular ramus, total length of the mandible, and length between the angular process and infradentale), and in some dental characters (length of the upper molar M¹). The most stable size dimorphism is manifested in the size of the canines, which is pronounced in all studied samples. SSD is not apparent in the length of the auditory bulla, the postorbital width, the minimum palatal width, the length of the lower molar M2, and the talonid length of the lower carnassial tooth M1.
Anatomical and histological study of the Malpighian tubules in the cicada genera Tibicen and Magicicada (Cicadoidea) demonstrated that, at the nymphal stage, these organs display a glandular modification, similar to one involved in the production of the “froth” in spittlebug nymphs (Cercopoidea). Proximal parts of the tubules contain a short smooth inflated segment, which produces granules of an acid mucopolysaccharide. A more distal long nodulose segment comprises cells which display extensive rough endoplasmic reticulum and numerous secretory vacuoles, indicating the manufacture of a proteinaceous product. These cells are strongly PAS-positive, suggesting the secretory product also contains carbohydrates. The production of secretory products in the tubules ceases at the adult stage. Available observations of the behaviors of cicada nymphs suggest that the tubule secretory products mix with copious watery excretion of the gut to form the anal liquid, which is used by the nymphs to cement the walls of the burrows and clean the body. The Malpighian tubule products apparently account for the adhesive properties of the anal liquid. The regional differentiation of the tubules, details of the cell ultrastructure in each of the segments, and the major secretory products are similar to those of spittlebug nymphs, which live immersed in their excretion which is conditioned with the Malpighian tubule secretory products. The results suggest that the distinctive adaptations of juvenile Cicadoidea and Cercopoidea have a common origin.
The molecular mechanisms underlying the adaptations to water loss developed in several tardigrade species remain poorly understood. It seems, however, that the binding of the disaccharide trehalose to membranes and other cellular components at low water contents is important for the tolerance to extreme drought. Trehalose is thus thought to replace interfacial- or “bound” water and enhance the conformational stability of labile macromolecules. To gain further insight into this we investigate here thermodynamic properties of water bound to the protein lysozyme at low water content (<100 water molecules pr. protein). It appears that this surface water has a higher enthalpy and higher entropy than the bulk liquid. These observations call for re-evaluation of the term “bound water” since “bound” carries the connotation of a low-energy, ordered (i.e. low-entropy) state.To rationalize these observations it is suggested that — in addition to the self-evident energetic contribution from biopolymer-water contacts — the properties of interfacial water are dominated by two effects. These are i) the ability of water to facilitate fast movements of individual parts of biopolymers and ii) the high molecular cohesion in the aqueous bulk. Thus, the hydration of a surface leads to enhanced flexibility in the biopolymer and breakage in the network of hydrogen bonding in the liquid bulk, and these effects collectively increase the enthalpy and entropy of the system. As a result, the thermodynamic parameters of hydration of lysozyme carry the thermodynamic hallmarks of an order → disorder process, even for the first hundred (i.e. most strongly associated) water molecules. We discuss these data for protein hydration together with some recent, very similar observations for the hydration of lipid bilayer membranes.
A comparative study of the bones of the shoulder girdle in the Piciformes, Passeriformes and Coraciiformes, and also in related orders of birds such as the Trogoniformes, Coliiformes, Apodiformes, Strigiformes and Caprimulgiformes, is presented and discussed. A number of observed characters justify inclusion only the families Indicatoridae, Picidae, Capitonidae and Ramphastidae in the order Piciformes, while also demonstrating a close resemblance with the Passeriformes that suggests a monophyletic origin for these two orders. On the other hand, although the closely related Bucconidae and Galbulidae are not included in the Piciformes they more closely resemble the Coraciiformes, particularly the Meropidae, Coraciidae and Brachypteraciidae. Among the Coraciiformes, it was observed that the Upupidae closely resemble the Phoeniculidae and, to a lesser extent, the Bucerotidae (particularly Tockus). For other coraciiforms, observation of shoulder girdle osteology alone did not provide sufficient evidence to justify a family grouping or a clearer definition of the boundaries of this order.
According to current theory, the splitting of a single species into two is best observed by a ring of intergrading populations which occupy a ring-shaped distribution area and whose terminal populations not only meet but overlap and co-occur without or with only little hybridization. The three most discussed examples in birds are revisited here. The great tit complex (Parus major s. l.) turned out to be an assemblage of four subspecies groups forming a secondary ring of population. The herring gull/lesser black-backed gull complex (Larus argentatus s. l.) forms a circumpolar circle of intergrading populations, but lacks the crucial cornerstone, the geographical overlap. The greenish warbler complex (Phylloscopus trochiloides s. l.) is close to the ideal ring species, but the ring is not complete and the Siberian zone of overlap needs further clarification and characterisation.