bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new species of agamid lizard from Ghana
Authors: Macdonald M. A. 
Published: August 2009

AbstractA new species of lizard of the genus Agama collected in the forest zone of Ghana is described. It occurs sympatrically with A. agama in S. W. Ghana and is related to that species and to A. paragama of Nigeria and Cameroun. The only known specimens form the type series. The known distribution based on sight records and specimens comprises the forest zone of Ghana west of 1d̀W and south of 7d̀N, but it is to be expected in Ivory Coast also. It appears to be rare or absent in the drier eastern Ghanaian forests. Although sympatric with A. agama, the two species occupy different habitats and rarely come in contact with each other, but in social behaviour they are similar. The new species may originally have been a rare animal of forest edge and natural breaks in primary forest. Recent disturbance of the forest may have allowed it to invade suitable artificial habitat within the secondary forest, arboreal plantations, and small clearings which are now the dominant habitats in the forest zone.
Factors affecting the reduction of the algal symbiont population in green hydra
Authors: Steele R. D. , Smith D. C. 
Published: August 2009

AbstractFor a given set of environmental conditions, the population of algal symbionts in green hydra remains at a constant level, indicating that the host animal exerts a regulatory influence on the size of its symbiont population. The experiments described here investigated those factors which can cause a reduction in the population size of symbionts: exposure to high light intensities, glycerol, darkness and the photosynthetic inhibitor DCMU. The purpose was to gain further insight into the mechanism of host regulation.Treatment with high light intensity caused the most rapid reduction in algal numbers, and could result in complete “bleaching” in a few days. Glycerol caused a slower marked reduction, with partial “bleaching”. Darkness reduced algal numbers, but did not eliminate symbionts; the effect of DCMU in the light was similar. Glycerol and DCMU accelerated the effect of high light intensity. Electron microscopy of algal and animal tissues showed that high light intensity and glycerol treatment caused the algae to appear degenerate or even disintegrating, but darkness and DCMU only caused minor morphological changes. It is concluded that the mechanism for symbiont regulation is complex, and involves the following separate components: sloughing off host cells containing symbionts; variation in growth rate of host relative to symbiont; regulation of symbiont growth; ejection of symbionts; digestion of symbionts (rare); detection of photosynthetic incompetence; detection of dead cells.
Demography of Gorilla gorilla
Authors: Harcourt A. H. , Fossey D. , Sabater‐Pi J. 
Published: August 2009

Data on population size, density and composition, biomass, group size and composition and reproductive rates are compared between populations in the two regions of gorilladistribution, equatorial west and east central Africa. The Virunga Volcano population of the latter region is shown to be a good model for all populations. Information on age at maturity, birth rates, mortality rates of adults and immatures and migration of individuals within the population is presented but data are available only for the Virunga population. The significance of a knowledge of the pattern of migration of individuals to the genetic consequences of large reduction in population size is stressed.
Evidence of denticles and attachment fibres in the superficial layer of scales in two fishes: Carassius auratus and Cyprinus carpio (Cyprinidae, Teleostei)
Authors: Zylberberg L. , Meunier F. J. 
Published: August 2009

An attempt is made to clarify the mechanisms of the scale anchorage in two Cyprinidae, the goldfish and the carp. Scanning and transmission electron microscope investigationsrevealed the presence of two different structures, denticles and collagen fibre bundles involved in the anchoring processes. These strucures are located on the upper part of thescales. Denticles form minute processes on the circuli of the anterior areas of the scales. Collagen fibre bundles arise from the superficial layer connecting the scale to the overlying dermis. These fibre bundles show structural similarities with the Sharpey's fibres and are named Sharpey‐fibre‐like bundles. Such fibres of attachment, not previously reported, can be considered as usual anchoring structures in fish scales.
A physiologically discrete population of chromatophres in Octopus vulgaris (Mollusca)
Authors: Andrews P. L. R. , Packard A. , Tansey E. M. 
Published: August 2009

Specimens of Octopus vulgaris (Cuvier) immersed in cold sea‐water (4°C) exhibit a flashing display of brown chromatophores that we call “brown spots”. The spots, which flashed approximately once every three seconds, are distributed over the dorsal skin of the head, mantle and arms and correspond mainly with the distribution of the white spots and white streaks previously described, and appear to act as a screen for the patches composing the white spots. Flashing brown spots could be evoked in animals with the supraoesophageal brain removed but not in animals with local denervation of the skin.The precise site of action of the cold is unknown but it is proposed that the nerves supplying the brown spot units are normally tonically inhibited and that the cooling process removes this inhibition and allows the spots to flash. They are particularly useful for the in vivo study of the control of chromatophores because they can be reliably activated and isolated from responses of other chromatophores.
Sexual reproduction in Epistomia bursaria (Bryozoa: Cheilostomata), an endozooidal brooder without polypide recycling
Authors: Dyrynda P. E. J. , King P. E. 
Published: August 2009

Epistomia bursaria L. is unusual amongst cheilostomes in that there is only one polypide generation per autozooid, together with endocoelomic embryonic brooding and larval viviparity. This combination, which gives the minimum possible fecundity of one larva per gynozooid is only known for one other cheilostome species, the majority of the rest being extracoelomic ovicellate brooders with polypide recycling. The greater fecundities exhibited by ovicellate and non‐brooding recyclers may offset the smaller degree of protection afforded by these reproductive strategies.Spermatogenesis and oogenesis are examined ultrastructurally. Whereas spermatogenesis is similar to that of other cheilostomes studied previously, oogenesis is very different. The egg at maturity is small and alecithal. Evidence suggests that endozooidal self‐fertilization occurs. Whereas nutrient for spermatogenesis and oogenesis is probably intrazooidal in origin, that for embryogenesis is derived inter‐zooidally.It is suggested that the combination of endocoelomic brooding, larval viviparity and one polypide generation may be a primitive feature from which recycling and extracoelomic brooding may have evolved.
Oxygen uptake and heart rate in young Green turtles (Chelonia mydas)
Authors: Davenport J. , Inagle G. , Hughes A. K. 
Published: August 2009

Oxygen uptake. heart rate and breathing frequencies were monitored in yearling Green turtles. Routine fed animals used about 100μ O2 g live turtle‐1 h‐1 at 25d̀C; this value was not significantly affected by size or short term food deprivation. Starved turtle showed a doubling of oxygen uptake after a satiation meal and heightened uptake persisted for five days. Between 15d̀ and 30d̀C oxygen consumption increased with rising temperature; below 15d̀C there was falling temperature. Vigorous activity increased oxygen uptake to two or three times thr routine fed levels.Turtles swimming gently at 25d̀C exhibited a heart rate of around 46–48 beats min‐1; this rose to 64–68 beats min‐1 during vigorous and continuous activity. Contrary to expectations profound bradycardia was not seen during diving; even during 10 min dives a rate of 25–28 beats min‐1 was sustained. Significantly lower heart rates were only seen in turtles which were apparently asleep.
The comparative morphology of the photophores of the squid Pyroteuthis margaritifera (Cephalopoda: Enoploteuthidae)
Authors: Butcher* S. , Dilly* P. N. , Herring** P. J. 
Published: August 2009

Pyroteuthis margaritifera has morphologically distinctive photophores on the tentacles, eyeball and in the mantle cavity. The photogenic tissue in each photophore is identical, has a blue‐green fluorescence and luminesces on treatment with dilute hydrogen peroxide. The photocytes frequently contain organized fibrillar material akin to that in the photocytes of certain other cephalopods. Several different types of blood vessel are present among the photocytes, including some, apparently restricted to the photophores, with a microvillous endothelium. Haemocyanin is present not only within identifiable blood vessels but also in some intercellular spaces.On the basis of their characteristic optical systems the photophores can be separated into three types: (1) tentacular; (2) ocular and anal; (3) branchial and median abdominal. The tentacular photophores have collagenous reflector and light guide systems and the median ones are double organs. The ocular and anal organs do not have collagenous optical structures but an elaborate variety of reflective iridosomes. Those in the aperture of the photophores appear to act as interference filters. The branchial and abdominal organs have iridosomes as the major reflective tissue but collagenous fibrils function as light guides in the aperture of these organs and their emission is diffuse rather than collimated.
The relation between maximal running speed and body mass in terrestrial mammals
Authors: Garland Theodore 
Published: August 2009

The available data on maximal running speeds of mammals are presented, and the relationship between speed and body mass is considered. For all mammals (n= 106), maximal running speed scales as (body mass)0–17; however, the largest mammals are not the fastest, and an optimal size with regards to running ability is suggested ( 119 kg). Maximal running speeds are, on the average, somewhat more than twice maximal aerobic speeds.Within the Artiodactyla, Carnivora or Rodentia, maximal running speed is mass independent, in agreement with theoretical expectations for geometrically similar animals (Thompson, 1917; Hill, 1950). McMahon's (1975b) model for elastic similarity is therefore not supported by the available data on maximal running speeds, and there appears to be no necessary correspondence between scaling of limb bone proportions and running ability.
Mechanics of locomotion and jumping in the forelimb of the horse (Equus): in vivo stress developed in the radius and metacarpus
Authors: Biewener A. A. , Thomason J. , Lanyon L. E. 
Published: August 2009

Principal stresses acting in the midshafts of the radius and metacarpus of the horse were determined from in vivo strain recordings during locomotion and jumping. Ground forces and limb position were also recorded. Over a range of speed and gait the radius was subjected to considerable bending, whereas the metacarpus was loaded primarily in axial compression. As a result, peak stresses acting in the radius (maximum: –45 MN/m2) were consistently 50% greater than those acting in the metacarpus (maximum: –31 MN/m2). The increase in peak bone stress (radius: 119% and metacarpus; 114%) with increasing speed was matched by a 103% increase in the mass‐specific vertical force (Av) exerted on the limb and a 55% decline in duty factor of the limb. The forelimb was closely aligned with the direction of ground force during the support phase (<9° when peak force acted) to minimize bending forces exerted on the distal limb bones. Hence, bending of the radius resulted mainly from axial forces acting about its longitudinal curvature. This was in contrast to the metacarpus, which is a much straighter bone.Significantly greater stresses were recorded in each bone during jumping: –81 MN/m2 in the radius and –53 MN/m2 in the metacarpus. While the distribution of loading in the radius was similar to that during steady state locomotion, greater variability in the magnitude and/or distribution of metacarpal loading was observed between animals, largely due to differences in the orientation of the limb during takeoff and landing. These data demonstrate that the horse, despite its large size, maintains a safety factor of nearly 3–4 during peak performance.
The mucus producing glands and the distribution of the cilia of the pulmonate slug Limax pseudoflavus
Authors: Cook Anthony , Shirbhate Rajshree 
Published: August 2009

The gross anatomy and histochemistry of the mucus‐producing glands of Limax pseudoflavus Evans were investigated. The body mucus can be divided into three areas. The dorsal body surface is covered with a sulphated acid mucopolysaccharide/protein mixture secreted largely by five cell types. The pedal mucus is a mixture of neutral mucopolysaccharide from the suprapedal gland. The dorsal and pedal mucus sheets are separated by the peripodal groove whose cells secrete a weakly acid mucus. The duct of the suprapedal gland, the epidermis around the pneumostome, the ventral surface of the peripodal groove and the centre of the underside of the foot are ciliated. The dorsal and pedal mucus remain stationary relative to the body and the substrate respectively and the only rejection currents seen in the mucus are around the pneumostome.It is suggested that the pedal mucus is formed by the mixture of the products of the suprapedal gland and the mucoprotein secreting gland in the leading edge of the foot, thus producing a mucus suitable for locomotion. Many areas of the animal (e.g. the head, pneumostome, sole and the leading edge of the foot) are capable of producing both a fluid (neutral or weakly acid) and a viscous (acid) mucus. It is postulated that such an arrangement allows for both adhesion and lubrication at different times.
A dynamic similarity hypothesis for the gaits of quadrupedal mammals
Authors: Alexander R. McN. , Jayes A. S. 
Published: August 2009

The dynamic similarity hypothesis postulates that different mammals move in a dynamically similar fashion whenever they travel at speeds that give them equal values of a dimensionless parameter, the Froude number. Thus, given information about one species, it could be possible to predict for others relationships between size, speed and features of gait such as stride length, duty factor, the phase relationships of the feet and the patterns of force exerted on the ground.Data for a diverse sample of mammals have been used to test the hypothesis. It is found to be tenable in many cases when comparisons are confined to quadrupedal mammals of the type described by Jenkins (1971) as “cursorial”. Most mammals of mass greater than 5 kg are of this type. Although the hypothesis applies less successfully to comparisons between cursorial and non‐cursorial mammals it is shown to be a reasonable approximation even for such comparisons and for comparisons between quadrupedal mammals and bipedal mammals and birds.
Wound healing and the haemocyte response in the skin of the Lesser octopus Eledone cirrhosa (Mollusca: Cephalopoda)
Authors: Polglase Jane L. , Bullock A. M. , Roberts R. J. 
Published: August 2009

The general structure of the skin of the Lesser octopus, Eledone cirrhosa is described. The component regions and cell types being (1) the epidermis, composed of columnar cells with a border of microvilli on their external surface, mucous cells and secretory cells of an unknown type, abutting a non cellular basal lamina; (2) the dermis, containing the elements of the colour change system, vascular and neural processes and an a cellular matrix.A sequential, morphological study of wound closure revealed three major mechanisms in the healing response; muscular contraction, a dermal cellular reaction and epidermal migration. The process of wound closure in Eledone is significantly slower than that seen, for example, in teleost fish (30 h rather than 30 min for the initiation of epidermal migration). The significance of these results in relation to the osmotic balance between seawater and the internal milieu of Eledone is discussed, together with their relevance to resistance against infection by pathogens.
The relationship between plasma progesterone and the timing of ovulation and early embryonic development in the marmoset monkey (Callithrix jacchus)
Authors: Harlow C. R. , Gems Sara , Hodges J. K. , Hearn J. P. 
Published: August 2009

Levels of progesterone in peripheral plasma samples showed a mean (± S.E.M.) ovarian cycle length of 28 ·63 ± 1·01 days (n= 19).The preovulatory, or follicular phase (mean ± S.E.M. length: 8·25 ± 0·30 days, n= 56) was defined as that period of the cycle during which progesterone levels remained below 10 ng/ml. The postovulatory, or luteal phase (mean ± S.E.M. length: 19·22 ± 0·63 days, n= 48) was defined as the remaining period of the cycle during which levels remained between 10 ng/ml and 150 ng/ml.The day of ovulation (day 0) was defined as that preceding the day on which progesterone levels first exceeded 10 ng/ml (day l), at the onset of the luteal phase. Oocytes and preim‐plantation embryos recovered from the reproductive tract provided supporting evidence for the timing of ovulation.The short follicular phase indicated that follicular growth may be initiated during the previous luteal phase. The long luteal phase may be related to the extended period of preim‐plantation development.
Aspects of the biology of the deep‐sea spider crab, Dorhynchus thomsoni (Crustacea: Brachyura)
Authors: Rice A. L. , Hartnoll R. G. 
Published: August 2009

Pelagic first crab stages of the deep‐sea spider crab, Dorhynchus thomsoni, are reported from mid‐water samples taken at a variety of localities in the Porcupine Seabight and the Rockall Trough. Some of these samples were from hauls made near the surface over depths of 3000 m or more.An analysis of these pelagic samples, and of benthic catches of D. thomsoni held by the Institute of Oceanographic Sciences and the British Museum (Natural History), indicate that most females and at least some males undergo the puberty prior to the third crab instar, these individuals therefore probably pass through a total of only three larval and three post‐laval instars. There is at least a possibility that some individuals moult after the moult of puberty, unlike any other spider crabs.
Structure, microbial associations and function of the so‐called “mixed segment” of the gut in two soil‐feeding termites, Procubitermes aburiensis and Cubitermes severus (Termitidae, Termitinae)
Authors: Bignell D. E. , Oskarsson H. , Anderson J. M. , Ineson P. , Wood T. G. 
Published: August 2009

The morphology, histology and ultrastructure of the mesenteric and proctodaeal components of the mixed segment are described in detail, together with the disposition of the associated gut musculature, the patterns of peristalsis and the streaming movements of soil particles in the gut lumen. The mesenteric epithelium is characterized by very extensive basal infoldings which are associated with a large population of mitochondria, but evidence of significant protein synthesis and secretion is lacking. It is proposed that this tissue is a transporting epithelium whose major function is the secretion of a copious, K+ ‐rich fluid into the intestinal lumen to irrigate the hindgut (proctodaeum) and that alkaline hydrolysis of humic fractions by this fluid is an essential component of digestion.Malpighian tubules are present, but do not participate in fluid excretion. Since the hind‐guts of soil‐feeding termites are exceptionally voluminous and elongated and the major symbiotic micro‐organisms occupy fixed positions by virtue of their attachment to the lining cuticle, it is argued that flushing is necessary to sustain microbial activity and for the recovery of end‐products by the host. A survey of the protodaeal epithelium suggests that the anterior colon (P4a) is the most likely site of fluid reabsorption and that the wall of the hindgut anterior to this site is impermeable. The greater degree of ultrastructural differentiation of the mixed segment of Cubitermes severus and its more complete morphological separation from the midgut suggests that this species is a more advanced soil‐feeder than Procubitermes aburiensis.
The biology and biomass of the skinks Mabuya sechellensis and Mabuya wrightii on Cousin Island, Seychelles (Reptilia: Scincidae)
Authors: de Brooke M. L. , Houston D. C. 
Published: August 2009

The skinks Mabuya sechellensis and M. wrightii scavenged among the seabird colonies of Cousin Island. particularly under the colony of Lesser noddies Anous tenuirostris which, in 1979, contained about 60.000 pairs. The density of skinks in different areas of the island did not vary greatly through the year. The mean density of M. sechellensis was 1393 individuals/ha equivalent to a biomass of 21.7 kg/ha and of M. wrightii 320 individuals/ha equivalent to 17.7 kg/ha. These biomass figures are the highest recorded for any terrestrial lizard population. Skink and Lesser noddy density were closely correlated. The skinks deposited fat equivalent to up to about 50% of their lean dry weight during the noddy nesting season but were leaner and lighter at other times. Our calculations of the amount of skink food emanating from the noddy colonies, in the form of faeces, dropped fish and eggs suggest that there is sufficient to maintain a skink population of the density observed.The skinks bred throughout the year, the larger M. wrightii more frequently than the smaller M. sechellensis, and the young/adult ratio was higher in M. wrigh:htii. The possible relevance of these differences to the two species' coexistence is discussed. The young/adult ratio varied according to skink density; in both species few young were found at high density.Mean home range sizes of M. sechellensis and M. wrightii were 26·6 and 78· m2, respectively.
The ecology of Saint Paul's Rocks (Equatorial Atlantic)
Authors: Edwards Alasdair , Lubbock Roger 
Published: August 2009

St Paul's Rocks are a remote group of islets, barely 400 m across, in the equatorial mid‐Atlantic (o°55'N 29°21'W). The results of a primarily zoological survey of the Rocks, carried out in September 1979 by the Cambridge Expedition to Saint Paul's Rocks, are reported. In addition, earlier studies of the Rocks' biology are discussed in the light of recent research. The terrestrial fauna is dominated by three species of sea‐bird and a land crab. Also reported from on land are a few species of insects, ticks and spiders, an endemic pseudoscorpion, and a centipede; the majority of these species are associated with the seabirds.The islets are devoid of tracheophytes, bryophytes and lichens.The marine ecology of the Rocks is discussed with respect to habitat. Five habitats are distinguished in the supralittoral and littoral zones; the fauna and to a limited extent the flora of each is described. Sublittorally the Rocks consist almost entirely of steep escarpments extending to 60 m depth and beyond. The shallow sublittoral (< 60 m deep) is divided into four habitats: (1) Palythoa zone; (2) Caulerpa zone; (3) sub‐Cauferpa zone, and (4) areas of unstable substrates. The Palythoa zone occupies a band extending from the base of the littoral to a depth of c. 5m and is dominated by a mat‐forming hexacoral, Palythoa caribaeorum. Below this zone to a depth of c. 33 m the rock faces are thickly invested by a species of green‐alga, Caulerpa racemosa. At depth this Caulerpa dominated zone is succeeded by an invertebrate dominated community. Unstable substrates are represented by a few pockets of coarse sand and some patches of rubble. The communities in each of these habitats are described. A primarily taxonomic review of the deep‐water fauna is also included. Finally, the influence of ocean currents on the zoogeographical relationships of the Rocks' fauna is briefly examined.