bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water, electrolyte and nitrogen balances of fat sand rats (Psammomys obesus) when consuming the saltbush Atriplex halimus
Authors: Kam M. , Degen A. Allan 
Published: March 2009

The fat sand rat (Psammomys obesus), a diurnal gerbillid rodent, is able to thrive while consuming only the saltbush Atriplex halimus. This plant has a high ash, nitrogen and water content but low energy yield. We measured the electrolyte, nitrogen (N) and water balances of fat sand rats in captivity when they were offered only A. halimus.The fat sand rats scraped the outer layers of A. halimus leaves before consuming them. This removed 14.3% to 19.6% of the ash content of the leaves, and thus substantially reduced the electrolyte intake of the fat sand rats. Total urine osmolality ranged between 2739 and 3098 mOsm/kg, with Na+, K+ and CI ‐ comprising 74.3% to 82.5% of the total osmolytes, percentages much higher than those usually found in desert rodents. Water intake was relatively high compared to other rodents because of the high water content of A. halimus. Evaporative water loss averaged approximately 50% of the total water output. Nitrogen requirements were easily fulfilled, even when the fat sand rats did not meet their energy requirements because of the high N content of the plant. Metabolic faecal nitrogen was 70.5 mg‐kg‐′ 75.d‐′, endogenous urinary nitrogen was 171.9 mg. kg‐0′75 d‐′ and minimal N requirements were 242.3 mg.k g‐75d‐1. Minimal N requirements for the fat sand rats were approximately 98% of that expected for a eutherian mammal of its body mass.It was concluded that fat sand rats can maintain water, electrolyte and nitrogen balances when consuming only A. halimus without producing highly concentrated urine. This is due, in part, to their ability to remove much of the electrolytes before consuming the plant and by producing urine of which Na+, K+ and C1‐ comprise a large percentage of the total osmolytes.
Comparative locomotor performance of marsupial and placental mammals
Authors: Garland T. , Geiser F. , Baudinette R. V. 
Published: March 2009

Marsupials are often considered inferior to placental mammals in a number of physiological characters. Because locomotor performance is presumed to be an important component of fitness, we compared marsupials and placentals with regard to both maximal running speeds and maximal aerobic speeds (=speed at which the maximal rate of oxygen consumption, VOlmax, is attained). Maximal aerobic speed is related to an animal's maximal sustainable speed, and hence is a useful comparative index of stamina.Maximal running speeds of 11 species of Australian marsupials, eight species of Australian murid rodents, two species of American didelphid marsupials, and two species of American rodents were measured in the laboratory and compared with data compiled from the literature. Our values are greater than, or equivalent to, those reported previously. Marsupials and placentals do not differ in maximal running speeds (nor do Australian rodents differ from non‐Australian rodents). Within these groups, however, species and families may differ considerably. Some of the interspecific variation in maximal running speeds is related to differences in habitat: species inhabiting open habitats (e.g. deserts) tend to be faster than are species from habitats with more cover, or arboreal species.Maximal aerobic speeds (compiled from the literature) were higher in large species than in small species. However, marsupials and placentals show no general difference with regard to maximal aerobic speeds.Maximal running speeds and maximal aerobic speeds for 18 species of mammals were not correlated, after correcting for correlations with body size. Thus, the fastest sprinters do not necessarily have high maximal aerobic speeds.
Taxonomic value of pore pattern in the integument of calanoid copepods (Crustacea)
Authors: Mauchline J. 
Published: March 2009

Integumental sensilla and gland openings occur in the integuments of calanoid copepods in what are, essentially, bilaterally symmetrical patterns. Their presence is most easily determined by digestion of the integument in hot alkali to destroy the soft tissues. The sites of the sensilla and gland openings are then seen in the integument, stained with chlorazol black, as spots of light under the light microscope. These pores, or holes, in the integument result from the digestion of the neural innervation of the sensilla or from the digestion of the ducts of the glands which traverse the integument from the epidermis to the outside. The patterns of distribution of these pores are examined in 249 species representing 89 genera ascribed to 28 families of the calanoid copepods. The investigation is confined to the patterns in the five metasomal segments of the species. The metasomal pattern is peculiar to most species and represents a species signature. The pore signature of an individual species consists of several constituent elements. The pores group into several complexes within which individual pores may or may not be developed in that species. The primary elements of these complexes are subscribed to by the signature of the superfamily to which the species belongs. The superfamilial signature with the addition of secondary elements forms the familial signature which is further diversified to form the generic signature. The generic signature is usually further complicated to produce the species signature. In some genera, however, the generic metasomal signature is not complicated to any degree in the constituent species and the distinctive elements of the species pore signature are found more or less restricted to the urosomal segments.These patterns of pores that can be traced from the species and genus through to the corresponding superfamily form one suite of pores. A second suite of pores is developed within some genera and families that probably represents specialization within these taxa. There is a gradual modification of the pore signatures that corresponds with current concepts of the phylogeny of the Copepoda.
Host‐parasite relationships between two seal populations and two species of Corynosoma (Acanthocephala) in Finland
Authors: Valtonen E. Tellervo , Helle E. 
Published: March 2009

Ringed seals (Phoca hispida botnica), from the Bothnian Bay, north‐eastern Baltic Sea were examined for acanthocephalan parasites in 1977–1982, and specimens from Lake Saimaa in south‐eastern Finland (P. h. saimensis) were examined in 1980–1981. The two seal stocks have been isolated from Arctic stock for 11,000 years and from each other for 8,000 years. Corynosoma strumosum and C. semerme were found in the Baltic seals, but only C. strumosum in those from the lake.Eighty two of the ringed seals caught in the Bothnian Bay were infected with both Corynosoma species, one with a single infection of C. strumosum and one with C. semerme in autumn. The total number of C. semerme increased in relation to the number of C. strumosum in each set of seals both in autumn and spring. Corynosoma semerme was dominant in most seals in spring, but in only an average of 60% in autumn. The predominance of C. strumosum in 40% of the autumn material (range 33–80%) is of interest because species ratio favouring C. strumosum is not found in any more heavily infected paratenic fish host of Corynosoma in the Bothnian Bay. The change in the Corynosoma species ratio of seals in autumn may be explained by their exceptional feeding behaviour at this time of the year (total or partial fasting) and the suggested longevity of C. strumosum as compared with C. semerme. The stability of the acanthocephalan populations in ringed seals is documented.
The fin musculature of cuttlefish and squid (Mollusca, Cephalopoda): morphology and mechanics
Authors: KIER WILLIAM M. 
Published: March 2009

The lateral fins of cuttlefish and squid consist of a tightly packed three‐dimensional array of musculature that lacks bony skeletal support or fluid‐filled cavities for hydrostatic skeletal support. During swimming and manoeuvring, the fins are bent upward and downward in undulatory waves. The fin musculature is arranged in three mutually perpendicular planes. Transverse muscle bundles extend parallel to the fin surface from the base of the fin to the fin margin. Dorso‐ventral muscle bundles extend from dorsal and ventral connective tissue fasciae to a median connective tissue fascia. A layer of longitudinal muscle bundles is situated adjacent to both the dorsal and ventral surface of the median fascia. The muscle fibres are obliquely striated and include a core of mitochondria. A zone of muscle fibres with a more extensive core of mitochondria is present in both the dorsal and the ventral transverse muscle bundles. It is hypothesized that these muscle masses include two fibre types with different aerobic capacity. A network of connective tissue fibres is present in the transverse and dorso‐ventral muscle masses. These fibres, probably collagen, are oriented at 45 to the long axes of the transverse and dorsoventral muscle fibres in transverse planes.A biomechanicayl analysis of the morphology suggests that support for fin movements is provided by simultaneous contractile activity of muscles of specific orientations in a manner similar to that proposed for other ‘muscular‐hydrostats’. The musculature therefore provides both the force and support for movement. Connective tissue fibres may aid in providing support and may also serve for elastic energy storage.
Burrow patterns of the mole rat Spalax ehrenbergi in two soil types (terra‐rossa and rendzina) in Mount Carmel, Israel
Authors: HETH GIORA 
Published: March 2009

Complete burrow systems of the mole rat Spalax ehrenbergi (Rodentia; Spalacidae), from two sites on Mount Carmel in Israel, with different soil types (terra‐rossa and rendzina), were excavated and described here for the first time.A comparison was made of burrow structure patterns in the two soils and of the sexes, with special attention to the features of the feeding tunnels.The pattern in the rendzina revealed longer burrows with a longer main tunnel and fewer branches per metre of the main tunnel, while the pattern in the terra‐rossa revealed shorter burrows with a shorter main tunnel and a relatively higher number of branches. These differences can primarily be related to the different levels of food availability, which is higher in the terra‐rossa. It is suggested that each of the patterns reflects the mole rat's ability to optimize foraging efficiency in accordance with its given food availability.The average total length of the males' burrows was much greater than those of the females' burrows in the rendzina soil. It appears that food requirements determine different burrow features of the sexes rather than reproduction requirements.Other tunnel features (e.g. structural complexity, depth and width, segment length and spatial arrangement) and the factors which may affect them, as well as burrow structure of young mole rats and evidence of the underground dispersion of young mole rats, were presented and discussed.Many similarities were found in a comparison of S. ehrenbergi burrow features with those of other solitary subterranean rodents.
The biology of Schizomus vinei (Chelicerata: Schizomida) in the caves of Cape Range, Western Australia
Authors: HUMPHREYS W. F. , ADAMS M. , VINE B. 
Published: March 2009

The chelicerate order Schizomida is represented in Western Australia by a single species, Schizomus vinei Harvey, from caves in the semi–arid Cape Range on the North West Cape peninsula. Schizomus vinei occurs in eight of 170 caves known from the range but is found only in areas where the relative humidity exceeds 92%. The schizomids are associated with a rich fauna (at least 11 species) mostly of detritivores, some of which show troglobitic adaptations. They prey on the cave animals that feed on detritus and are known to eat oniscoid isopods, millipedes, cockroaches, worms and S. vinei.The size class structure of the population in cave C 118 was strongly skewed negatively suggesting that the smaller size classes occupy interstices of the infill of sumps. Schizomids in this cave were found to be distributed at random up to the third nearest neighbour. The minimum population size, with 95% confidence, was estimated to be 1323 individuals. Schizomus vinei grew very slowly in vivaria. One female produced nine eggs which did not survive. Schizomus vinei has a high mean rate of water loss (470–4 mg g‐1 h‐1) and a low resistance to water loss (15–2 cm sec‐1); their resistance is about 10 x greater than that of a free water surface, but is about two orders of magnitude lower than that of some spiders and scorpions. Schizomus vinei excretes a clear fluid and may be ammonotelic.Allozyme electrophoresis strongly suggests that individuals from the different caves are of the same species. Consideration of climate, age of separation of the caves and the general biology of the schizomids suggests that those caves containing schizomids may be linked.
The morphology of the lung of a tropical terrestrial slug Trichotoxon copleyi (Mollusca: Gastropoda: Pulmonata): A scanning and transmission electron microscopic study
Authors: MAINA J. N. 
Published: March 2009

The lung of the slug Trichotoxon copleyi is located in the body mantle where it opens to the outside through an adjustable pneumostome situated on the right side. The respiratory surface of the lung is profusely vascularized by anastomosing ‘blood’ capillaries. A thick muscular layer surrounds the gas exchange surface and may be involved in the efficient rhythmic ventilatory contraction of the lung. Externally an epithelial layer made up of large secretory cells with numerous microvilli overlies the muscular layer. The surface of the lung is made up of squamous cells with an abundance of microvilli and clustered goblet cells interspersed occasionally. The squamous cells cover the notably thin air–blood barrier which is extremely attenuated, particularly in some areas. The goblet cells contain a centrally located nucleus and numerous intracytoplasmic granules, presumably precursors of the mucus that covers the surface of the mantle cavity.All the essential morphological prerequisites for efficient gas exchange such as an extensive surface and a thin blood–gas barrier were observed in the lung of Trichotoxon. It was concluded that this molluscan lung is structurally and functionally a true lung in all respects.
Observations on the polyphyodont dentition of Hemiphractus proboscideus (Anura: Hylidae)
Authors: SHAW J. P. 
Published: March 2009

In Hemiphractus fang–like teeth are ankylosed to the premaxilla, maxilla and prevomer, and bony odontoids are found on the dentary, angular and palatine bones. The odontoids are small, but a larger pair at the front of the lower jaw project upwards and backwards into the mouth and fit into a diastema between the anterior premaxillary teeth when the mouth is closed.The teeth are unipartite and monocuspid, and each consists of a strongly recurved and elongated cone of orthodentine, capped at the tip by a thin layer of enamel. The inner circumpulpal layer of the dentine is tubular, but no tubules are present in the outer pallial layer. During tooth development, dentine is formed before the enamel matrix is produced, and the tooth germs lie horizontally beneath the ventral surface of each dentigerous bone. On eruption, the tooth germs migrate horizontally and become ankylosed to the outer edge of the jaw bone by a layer of cellular cementum.During tooth replacement, the vast majority of the dentine of each tooth, and the cementum at the tooth base, are resorbed by osteoclasts. It is not clear whether the tips of the teeth are shed or not.
A quantitative theory of expected volume changes of the mouth during feeding in teleost fishes
Authors: MULLER M. 
Published: March 2009

The mechanism of mouth expansion in fish, consisting of jaws, suspensoria (j) and hyoids (h) has been modelled by a four‐bar isosceles linkage. This model provides insight into limitations and demands of the expansion system used in feeding, as it can be optimized with regard to maximum mouth volume increase. The optimum length ratio of hyoids and jaws was found to be h/j = 0–7. This optimum is modified by mouth bottom depression, jaw protrusion and swimming.To expand the mouth, at least two forces are required; one exerted by the sternohyoid and ventral body muscles, the other by the epaxial muscles through transmission in the quadrato‐articular joints. (Data from EMG experiments confirm the synchronous activity of these muscle groups.) Force transmission and mouth volume increase are constraining quantities, which can be compromised. This leads to a model of the initial mouth shape which is actually found in many ‘generalized’ fishes, and to demands concerning volume and physiological cross‐sectional area of the muscles involved.Options for specific relative lengths of jaws and hyoids (h/j‐ratios) are, for various fish species, compared with model predictions. The applicability of the model approach is shown by the obtained results.
The annual cycle in body weight of small mammals from the Transvaal, South Africa, as an adaptation to a subtropical seasonal environment
Authors: KORN HORST 
Published: March 2009

Seasonal breeding of non‐hibernating small mammals is generally associated with a reduction in body weight during the non‐breeding period. In aseasonal breeders and in exceptional situations, when winter breeding occurs, this pattern cannot be found.The reduction in body weight is thought to be a means to reduce energy requirements during the harsh non‐breeding season that can either be winter, in the Holarctic, or the dry season in the Transvaal highveld.The controlling mechanism in the strongly seasonal subtropical environment in southern Africa seems to be photoperiod as in small mammals from the northern hemisphere.Since a general agreement in body weight changes was found in rodents and shrews from both areas, further similarities in adaptations to strongly seasonal environments in the subtropics are expected.For the first time it is shown that the adaptive responses of small mammals to unfavourable seasons are similar in the Holarctic and seasonal subtropical areas.
Pre‐ and post‐natal development of pouched mice, Saccostomus campestris
Authors: AARDE LILIAN M. WESTLIN‐VAN 
Published: March 2009

Pre‐ and post‐natal growth of the pouched mouse (Saccostomus campestris) were investigated and growth curves were calculated as described by Stevens (1951). Measured values of foetal weights put into Huggett & Widdas' equation (1951) revealed that the actual correction factor for species with a gestation period of 50 days or shorter was different from the one given by Huggett & Widdas. Therefore, the calculated value of specific growth velocity for pouched mice was lower than when using the correction factor given by Huggett & Widdas (1951).Ninety percent of the asymptotic body weight was attained at an average age of 135.2 and 143.1 days for males and females, respectively, while 90% of the asymptotic body length was achieved when males and females were 71.9 and 69.3 days old, respectively. Post‐natal growth rates of females and males were not significantly different from each other, and the average rate of weight increase for male and female pouched mice was lower than for other rodents studied (see Case, 1978).Ages at which tooth eruption, eye‐opening and eye usage occurred were also recorded.
Nutritional ecology of a browsing ruminant, the kudu (Tragelaphus strepsiceros), through the seasonal cycle
Authors: Owen‐Smith Norman , Cooper Susan M. 
Published: March 2009

The activities and food selection of four hand‐reared kudus were recorded in a large fenced enclosure containing natural savanna vegetation in the Nylsvley Nature Reserve, South Africa. Leaves of selected species were analysed chemically for crude protein, fibre constituents, phosphorus, condensed tannin and total polyphenols. Available protein and metabolizable energy were estimated allowing for potential antinutritional effects of tannins.Leaves of palatable deciduous woody plants and herbaceous forbs formed the main dietary constituents during the late wet season. Foliage from palatable evergreens and robust forbs were added to the diet during the dry season. Towards the end of the dry season unpalatable species of evergreens were eaten. At the start of the growing season new leaves of otherwise unpalatable woody species formed the staple food source, together with fruits of Strychnos spp. Correspondingly, protein and digestible dry matter concentrations in the diet declined to reach a low at the end of the dry season.Total daily food intake increased to compensate for reduced dietary quality during the dry season, until little edible foliage remained. While the estimated daily intake of protein remained well above maintenance requirements, the estimated metabolizable energy intake fell below requirements during the late dry season. Phosphorus intake may have been submaintenance in the dry season. Nutritional balance was dependent on the availability of particular vegetation components to serve as nutritional stepping stones during crucial times of the year. These included forbs during the late wet season, palatable evergreens in the dry season, and Strychnos fruits plus early‐flushing woody plants during the dry season‐wet season transition.
Seasonal and diel behaviour of radio‐tagged Clarias gariepinus in Lake Ngezi, Zimbabwe (Pisces: Clariidae)
Authors: Hocutt Charles H. 
Published: March 2009

Seasonal and diel behaviour of six sharptooth catfish, Clarius gariepinus (Burchell), was monitored in Lake Ngezi, Zimbabwe, from May 1986 to February 1987. All specimens were equipped with surgically‐implanted radiotransmi tters, 48–49 mHz, after they were anaesthetized in 6 mg l‐1 quinaldine. This represented the first known use of this methodology in subSaharan Africa.It was determined that C. gariepinus exhibited three movement patterns on a day‐to‐day basis: long‐distance movements ( 2200 m), moderate movements (c. 40–200 m) and local movements (<40 m). Major movements were not restricted to night‐time conditions, nor were inshore/offshore movements related to time of day. Seasonal activity peaks occurred in July/August 1986 and again in January 1987, with rate of swimming exceeding 470 m/h on some occasions. Home range of some individuals encompassed the entire lake (> 5 km2).
Ecology of Chondromorpha kelaarti (Diplopoda, Polydesmida)
Authors: Bhakat Somnath 
Published: March 2009

Stadia 11‐VII and adults of Chondromorpha kelaarti (Humbert) can be separated by segment number, length, breadth and paired legs. Sexes are distinguished from stadium IV and the sex ratio vaned around SO%, though females were prevalent in May and June.In females, a positive and significant correlation was found between number ofeggs present and body width at the 17th Segment.Population density and biomass of C. kelaarti varied from 0.06 to 12.94 and 1.75 mg to 811.24 mg per 0.1 mz, respectively. From May to November, populations of C. kelaartiare aggregated in distribution.Chondronrorphu keluurti passed the dry season in late stadia (VI, VII and adult) and may complete the life cycle in one or two years.