bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of size on the optimal shapes of gliding insects and seeds
Authors: Ennos A. Roland 
Published: March 2009

Conventional aerodynamic arguments suggest that possession of high aspect ratio wings will always improve the flight performance of glides. Drag and power will be minimized at intermediate flight speeds. It is shown, however, that as the aspect ratio increases, these minimum drag speeds are reduced, and will fall below the stall speed of the glider. This will happen at lower aspect ratios in small gliders, which operate at higher profile drag coefficients. Increasing the aspect ratio further will improve performance less than this analysis suggests.A detailed analysis is developed to calculate the optimum shape of small gliders. Profile drag increases with aspect ratio, owing to the fall in the Reynolds number, while induced drag falls with increasing aspect ratio. Minimum drag will be encountered and hence the glide angle will be minimized at intermediate values of aspect ratio. Best glide angles are achieved at low speeds (high lift coefficients) and the optimum aspect ratio increases with the mass of the glider.Small natural gliders possess large, low aspect ratio wings. The aspect ratios are generally somewhat below those which would produce the best glide angle at stall speed, but should give a reasonable performance over a range of speeds.
The development of an enzyme‐immunoassay for urinary pregnanediol‐3‐glucuronide and its application to reproductive assessment in exotic mammals
Authors: Hodges J. K. , Green D. I. 
Published: March 2009

Measurement of urinary pregnanediol‐3‐glucuronide (PdG) provides a practical, non‐invasive method for monitoring ovarian function and pregnancy in diverse mammalian species. To date, however, methods of laboratory analysis have relied on radio‐immunoassay procedures which, because of their cost and the problems associated with the use and disposal of radioactive substances, have limited potential for routine application in zoos and other animal collections with limited laboratory facilities. The present paper reports the development of a non‐isotopic enzyme‐immunoassay for the measurement of urinary PdG in a wide range of exotic mammals and describes its application to reproductive assessment in the gorilla and rhinoceros.The assay is based on an homologous competitive binding system and utilizes antiserum raised against PdG‐bovine serum albumen and alkaline phosphatase‐PdG, prepared by the active ester technique, as conjugate. Sensitivity of the assay is between 12.5 and 25 pg/well and precision, expressed as the intra‐ and inter‐assay coefficients of variation, is between 5.3 and 7.8% and 9.2 and 16.1%, respectively. Serial dilutions of human, gorilla, orang‐utan, mangabey, blackbuck, okapi, gaur, giant panda and Indian, black and white rhinoceros urine gave displacement curves parallel to that of the PdG standard, indicating the potential of the assay for multi‐species application.The pattern of excretion of immunoreactive PdG during successive menstrual cycles and two complete pregnancies in a gorilla is described. Follicular phase levels of PdG were low (0.07–0.13 μg/mg creatinine (Cr)), in contrast to the high levels of excretion during the luteal phase (maximum values 1.5–2.1 μg/mg Cr). Mean cycle length was 29.6±1.5 days with a range of 26–34 (n = 5). The pattern of PdG excretion during pregnancy showed a slow increase during the first 60 days and a more rapid rise to values of 8–12 μg/mg Cr after 120 days, with no further consistent increase during the remaining period of pregnancy. Estimated gestation lengths were 280 and 256 days.The levels of immunoreactive PdG excreted during mid‐to‐late pregnancy varied considerably between the three species of rhinoceros, maximum values ranging from up to 10 μg/mg Cr in the Indian to 0.08 μg/mg Cr in the white rhinoceros. Despite this variation pregnancy was associated with elevated PdG excretion in all three species and each profile showed a marked fall in levels at the end of the gestation period. The results suggest potential for urinary PdG determination as a practical method of pregnancy detection in both Indian and African rhinoceros, although species differences in the relative importance of PdG as a progesterone metabolite probably exist.
Liver and plasma retinol (vitamin A) in wild, and liver retinol in captive penguins (Spheniscidae)
Authors: Ghebrmeskel K. , Williams G. , Keymer I. F. , Horsley D. T. 
Published: March 2009

In rockhopper penguins (Eudyptes crestatus), liver concentrations of retinol (vitamin A) were significantly higher in post‐moult than in pre‐moult birds. In Magellanic penguins (Spheniscus magelianicus), plasma concentrations of retinol were significantly higher in post‐moult than in pre‐moult birds; liver retinol concentrations were also higher, but not significantly so.The pre‐ and post‐moult Magellanics had higher liver and lower plasma retinol concentrations than the pre‐ and post‐moult rockhoppers.Captive blackfooted (jackass) (Spheniscus demersus), king (Aptenodytes patagonica) and Humboldt (Spheniscus humboldti) penguins had liver vitamin A stores significantly lower than those of the free‐living rockhopper, Magellanic, gentoo (Pygoscelis papua), emperor (Aptenodytes forsteri), chinstraps (Pygoscelis antarctica) and Adélie (Pygoscelis adeliae) penguins.
The distribution of the millipede Ommatoiulus moreleti (Diplopoda, Julida: Julidae) in relation to other Ommatoiulus species on the south‐western Iberian Peninsula
Authors: Bailey P. T. , Mendonça Teresa Rita de 
Published: March 2009

Ommatoiuius moreleti(Lucas) occurs naturally in Portugal and Spain, and has been introduced to some Atlantic Islands, South Africa and southern Australia, where it is widespread and numerous.In southern Portugal and south‐west Spain, O. moreleti shares its range with O. oliveirae (Verhoeff), O. cingulatus (Attems) and several undescribed Ommatoiulus spp. In a study area where O. moreleti was confined to deep litter beneath Quercus trees, O. oliveirae predominated in litter of the bushes Cistus spp., while O. cingulatus was most numerous in an area dominated by grasses and herbs, but with little litter. The three species tended to eat different food items, but this probably reflected local availability rather than preference. Ommatoiulus moreleti has a distinct western boundary which broadly corresponds with changes in the quantity of litter on the ground. The distribution of O. moreleti was related to the availability of deep litter, often provided by Pinus and Quercus trees, but also by dense shrubs and heath, and undisturbed grassland.In addition to providing food, litter provides a refuge for O. moreleti. Grassland species such as O. cingulutus live where there is little litter, and probably have to dig deep in the soil to avoid summer desiccation and predation of immature stages. It is suggested that soil hardness and litter depth may be important determinants in the distribution of O. moreleti, and relative digging ability may explain the partitioning of the habitat between the three species studied.
The food and feeding habits of two co‐occurring marine catfish Galeichthys feliceps and G. ater (Osteichthyes: Ariidae) along the south‐east coast of South Africa
Authors: Tilney R. L. , Hecht T. 
Published: March 2009

The feeding‐associated morphological structures of the two Galeichthys species were found to be similar in all respects. Interspecific competition for food was avoided through habitat separation. Habitat preference, as established by dietary analysis and fishing trials, was based on substratum type. Galeichthys feliceps fed over sandy and muddy substrata in marine and estuarine environments, while G. ater fed exclusively over marine reefs. The two species have different caudal fin structures which are probably evolutionary responses to habitat‐associated behavioural requirements in the two different environments.The diets of the two species were investigated and compared using calorific values of prey items. While both species fed predominantly on benthic crustaceans, polychaetes and molluscs, little dietary overlap occurred at the species level. In the estuarine environment, G. feliceps fed mainly on the anomurans Upogebia africana and Calianassa kraussi, crabs Hymenosoma orbiculare and Cleislosoma edwardsii, and several isopod species. In the marine environment G. feliceps fed mainly on two species of crabs, Thaumastoplax spiralis and Goneplax angulata, the echiurid Ochaetostoma capense and the sedentary polychaete Sternaspsis scutata. A high incidence of teleost scales in the diet of G. feliceps juveniles was found to be a consequence of scavenging rather than a lepidophagous habit. Galeichthys ater fed widely on several reef‐associated crabs, isopods, polychaetes and cephalopods.
Morphometrics and allometry in the trophically polymorphic cichlid fish, Cichlasoma citrinellum: Alternative adaptations and ontogenetic changes in shape
Authors: Meyer Axel 
Published: March 2009

The Neotropical cichlid fish Cichlasoma citrinellum exhibits a distinct trophic polymorphism in the structure of its pharyngeal jaws. Fish have either strong, sturdy molariform pharyngeal jaws or weak papilliform jaws. Intermediate forms are rare among adults. Ontogenetically, however, all fish start as papilliform morphs. Differences in morphology and allometry between morphs in external measurements (25 measurements) and measurements of the lower pharyngeal jaws (nine measurements) were analysed using a multivariate morphometric approach. The ontogenetic growth trajectories for the pharyngeal jaws of the respective morphs start to diverge early in ontogeny and therefore seem to preclude the existence of adult intermediate morphs. The isometric growth of the tooth diameter in molariform morphs (in relation to standard length), versus its relatively retarded (negatively allometric) growth in the papilliform morph, is the main cause for the development of distinct trophic morphs in pharyngeal‐jaw morphology. At approximately 50 mm standard length, both pharyngeal morphs can be discerned clearly. In this study only larger fish of determined pharyngeal‐jaw morphology were considered (n= 30 for molariform morphs, n= 31 for papilliform morphs). External morphology differs between morphs as well, but less perceptibly. Principal‐components analyses revealed that only a few measures load highly on PC2 and therefore account for most of the differences between the two trophic morphs in the shape of the external morphology. Molariform morphs have blunter, shorter snouts, larger eyes and deeper, shorter bodies than papilliform morphs.The two external morphologies resemble other known limnetic and benthic body shapes of polymorphic species of fishes, and are believed to enhance the ecological separation of the two pharyngeal‐jaw morphs. Evolutionary implications of ontogenetic changes and adult differences in morphology and trophic polymorphism are manifold. The alternative adaptations in this polymorphic species will decrease intraspecific competition by differential niche utilization and habitat choice, thus allowing for larger population sizes. Alternative adaptations may eventually lead to genetic isolation and possibly speciation of the two trophic morphs.
Habitat usage by red (Cervus elaphus) and roe (Capreolus capreolus) deer in a Scottish Sitka spruce plantation
Authors: Welch D. , Staines B. W. , Catt D. C. , Scott D. 
Published: March 2009

Habitat usage in a 1825 ha block of mixed‐age forest was assessed by counts of accumulated pellet groups on permanent plots. This monitoring took place from 1978 to 1984 with some 300 plots in 13 types of habitat. Tests on the method are described; losses of pellet groups were insufficient to bias the conclusions.Usage was least in the forest stages lacking ground vegetation, i.e. thicket, pole and high‐canopy forest; stages with ground vegetation had moderately heavy usage. The most preferred habitats were of small extent, treeless, and situated near or within closed forest, i.e. rides, openings and the margin between forest and unplanted hill ground. Red and roe deer showed broadly similar patterns of preference but differed significantly in the use of some habitats. Thickets received more use from red than roe deer, whereas pre‐thicket and vegetated high‐canopy forest had most use from roe deer, being richer in forbs on which this species feeds heavily.
The architecture of the spleen of the yellow‐bellied toad, Bombina variegata
Authors: Dulak Józef 
Published: March 2009

The spleen of the yellow‐bellied toad, Bombina variegata, consists of distinct white and red pulps. The well‐developed white pulp is formed by a large central lymphocytic region around the numerous blood vessels and by its smaller peripheral ramifications, both surrounded by the more or less developed connective tissue boundary layer. Large peripheral sinuses of the white pulp, filled mostly with lymphocytes, are usually present at the inner side of this boundary. At the outer side of the boundary layer, the lymphocytic marginal zone is often observed. This zone merges into the erythrocyte‐rich red pulp formed by cellular cords and small venous sinusoids.The structure of the spleen of Bombina variegata differs considerably from the spleens of other anuran species studied so far. The highly developed white pulp and its distinct separation from the red pulp may be connected with the important role of the spleen as the main secondary lymphoid organ of B. variegata. The splenic compartmentalization makes the yellow‐bellied toads a useful model for experimental immunobiological studies.
Sexual dimorphism of auditory function and structure in praying mantises (Mantodea; Dictyoptera)
Authors: Yager David D. 
Published: March 2009

Sexual dimorphism of tympanate auditory systems in insects has bees described in only a few taxonomically isolated cases. However, widespread sexual dimorphism occurs in the ultrasound‐sensitive, midline ear of the praying mantis.In dimorphic species, it is always the female mantis that shows a reduction in ultrasonic hearing. The dimorphism may be mild—a difference in tuning and small reduction in sensitivity—or extreme with no evidence of audition in the female. In all but the mildest cases, the reduction in hearing is accompanied by significant anatomical divergence from the male ear structure. Two distinct metathoracic groove (‘ear’) types are linked to hearing reduction in the females.Anatomical evidence of auditory sexual dimorphism appears in 34% of the 183 mantis genera examined. The dimorphic genera are widely but non‐uniformly distributed within three of the four largest mantis families.Auditory sexual dimorphism is closely correlated with dimorphism in wing length. In general, mantises with functional wings have sensitive ultrasonic hearing while those with short wings do not. These findings support the hypothesis that ultrasonic hearing in mantises is part of a defensive system against attack by echolocating bats.
Sexual differentiation in the grey short‐tailed opossum, Monodelphis domestica, and the effect of oestradiol benzoate on development in the male
Authors: Moore H. D. M. , Thurstan S. M. 
Published: March 2009

Observations were made of the early differentiation of the gonad in the grey short‐tailed opossum, Monodelphis domestica, using light and electron microscopy. An investigation was made also of the effects of neonatal treatment with oestradiol benzoate on sexual differentiation.Neonates were removed from the nipple at various times after birth (0‐14 days), killed and karyotyped to determine the genetic sex. Some individuals were then fixed in buffered formalin, embedded in paraffin and prepared for light microscopy. Alternatively the mesonephri and gonadal anlagen were dissected free of tissue, fixed in buffered 2.5% glutaraldehyde and prepared for electron microscopy. Twenty‐two offspring from nine litters were examined.At birth, pups were sexually undifferentiated and had rudimentary indifferent gonadal anlagen. By three days after birth, the gonad rudiments of males exhibited the first formation of sex cords with the coalescing of presumptive Sertoli cells. The sex cords of males were well defined by six days. By contrast, the gonads of female pups failed to display defined sex cords up to two weeks after birth.An unusual feature was the initial appearance of a scrotal bulge in males as early as two days after birth, thus preceding any obvious morphological gonadal differentiation.In all 34 pups were coated with oestradiol (1‐2 μg per application) for various lengths of time. Some individuals were allowed to reach maturity so that growth rate and sexual behaviour could be studied.Oestradiol treatment had a profound effect on male neonates, but no apparent effect on female neonates. Testis development was inhibited with the failure of the rudimentary gonad to form sex cords. With the exception of near‐normal scrotum development, external and internal genitalia were completely feminized. Treated males allowed to reach maturity had growth rates similar to control females and exhibited oestrous behaviour in the presence of a control male.The results suggest that gonadal differentiation in marsupials can be profoundly influenced by exogenous hormone. The early development of a scrotal bulge, preceding morphological differentiation, and the lack of an effect of oestradiol on scrotal formation would indicate that the differentiation of this somatic tissue may not be dependent on gonadal determination.
Metamorphosis of the feeding mechanism in tiger salamanders (Ambystoma tigrinum): the ontogeny of cranial muscle mass
Authors: Lauder G. V. , Reilly S. M. 
Published: March 2009

Most previous research on metamorphosis of the musculoskeletal system in vertebrates has focused on the transformation of the skeleton. In this paper we focus on the transformation of the muscles of the head during metamorphosis in tiger salamanders (Ambystoma tigrinum) in order (1) to provide new data on changes in myology during ontogeny, and (2) to aid in interpreting previous data on the metamorphosis of function in the head of salamanders.The physiological cross‐sectional area of nine head muscles was calculated by measuring fibre angles, fibre lengths, and muscle mass in two samples of tiger salamanders obtained just before and just after metamorphosis. The major mouth‐opening muscles (rectus cervicis and depressor mandibulae) exhibit a significant decrease in estimated maximum tetanic tension (MTT) across metamorphosis of about 36%. The jaw‐closing muscles (adductor mandibulae internus and externus) and the head‐lifting muscles (epaxials) also decrease in MTT but not significantly. The muscles associated with tongue projection during feeding on land (the subarcualis rectus I, geniohyoideus, interhyoideus and intermandibularis) all show a slight increase in MTT at metamorphosis.Metamorphic transformation of feeding behaviour in Ambystoma tigrinum involves changes in performance, the design of skeletal elements, changes in muscle force‐generating capability, and changes in hydrodynamic design from unidirectional flow in larvae to bidirectional flow during aquatic feeding after metamorphosis. Although muscle activity patterns during aquatic feeding do not change across metamorphosis, tongue‐based terrestrial feeding involves a suite of novel muscle activity patterns, morphological characters acquired at metamorphosis, and a metamorphic increase in the masses of muscles important in tongue projection.
Neolepetopsidae, a new docoglossate limpet family from hydrothermal vents and its relevance to patellogastropod evolution
Authors: McLean James H. 
Published: March 2009

Six new species of limpets from hydrothermal vents at spreading centres, hydrothermal vents on seamounts, or cold sulphide seeps are described in three new genera in the new family Neolepetopsidae. Anatomy is detailed separately by V. Fretter (1990). The family is considered to be a living descendant of the Palaeozoic‐Mesozoic family Lepetopsidae (proposed herein), based on Lepetopsis Whitfield, 1882. Both families are placed in the new superfamily Lepetopsacea, new suborder Lepetopsina, order Patellogastropoda.New genera and species are: Neolepetopsis, type species N. gordensis, from the Gorda Ridge, and three additional species: N. densata, from an active sulphide chimney near 12°N on the East Pacific Rise, N. verruca from a sulphide chimney near 21° N on the East Pacific Rise, and N. occulla from hydrothermal vents on the caldera floor of Green Seamount near 21° N; Eulepetopsis, type species E. vitrea, from hydrothermal vents at the Galapagos Rift and the East Pacific Rise near 21°, 13°and 11°N; Paralepetopsis, type species P. floridensis, from cool, hypersaline, sulphide seeps at the base of the continental slope off the west coast of Florida.Inclusion in Patellogastropoda is indicated by plesiomorphic characters: symmetrical shell lacking coiled phase, no epipodium in adult, single dorsally arched jaw, docoglossate dentition with a licker below the tip of the radula, both left and right kidney, and gonad discharging through right kidney.The radula differs from that of other patellogastropods in having the denticle caps delicate and non‐mineralized, the shafts articulating with shafts and cusps of adjacent teeth in the row and with those in adjacent rows, and in having some capacity for longitudinal bending. The rachidian is well developed; the first two pairs of lateral teeth are regarded as homologues of the inner lateral teeth of Patella; the third lateral tooth is larger than the others and is considered a modified pluricuspid tooth; there are two pairs of plate‐like marginals. Tooth morphology differs in each genus but all have a very long second lateral with a strong mid‐shaft nub to articulate with the overhanging edge of the pluricuspid.The neolepetopsid radula is interpreted as close to that of the patellogastropod archetype except for its lack of mineralization and reduction in the number of marginal teeth. The radula in living docoglossate outgroups (chitons and monoplacophorans) is mineralized and the teeth are articulating. Articulating teeth are therefore regarded as plesiomorphic in patellogastropods.I speculate that articulating teeth may have been characteristic of Palaeozoic and early Mesozoic patellogastropods and that the non‐articulating, straight‐shafted and rapidly replaced teeth of extant Patellina may have arisen in the Mesozoic, a time at which patellogastropods of modern appearance underwent a radiation in shallow‐water habitats.