Morphometric analysis of Crocodylus porosus from the north coast of Arnhem Land, Northern Australia

1978 ◽  
Vol 26 (1) ◽  
pp. 1 ◽  
Author(s):  
. Webb.G.J.W ◽  
H Messel
Keyword(s):  
Body Size ◽  
Specific Problem ◽  
Maximum Size ◽  
The Body ◽  
Tissue Loss ◽  
North Coast ◽  
Northern Australia ◽  
The North ◽  
Crocodylus Porosus ◽  
Mandibular Teeth

Utilizing measurements from 1354 C. porosus, we have derived formulae for predicting snout-vent length from 17 other attributes. The specific problem of predicting body size from an isolated head or skull is treated separately and some data are presented on proportional tissue loss in skull preparation. Sexual dimorphism was examined, and is demonstrated in interocular width, the width at the midpoint of the cranial platform, and the length of the tail. Discriminant analysis has been used to distinguish males from females on the basis of external measurements of both the whole animal and the isolated head. Hatchling C. porosus from Arnhem Bay and the Blyth River have longer heads than those from the Liverpool River. C. porosus from Sarawak have longer tails and are heavier than those from northern Australia. Predicting the maximum size of C. porosus from large skulls in museums is difficult because of variations in basic skull shape. The body size at which mandibular teeth protrude through the premaxilla is quantified.

An Aerial Survey of Potential Nesting Areas of the Saltwater Crocodile, Crocodylus porosus Schneider, on the North Coast of Arnehem Land, Northern Australia

1978 ◽  
Vol 5 (3) ◽  
pp. 401 ◽  
Author(s):  
WE Magnusson ◽  
GC Grigg ◽  
JA Taylor
Keyword(s):  
Coastal Wetlands ◽  
Aerial Survey ◽  
North Coast ◽  
Northern Australia ◽  
National Library ◽  
The North ◽  
Arnhem Land ◽  
Saltwater Crocodile ◽  
Different Types ◽  
Crocodylus Porosus

Results of a study of habitats used by C, povosus for nesting on the Liverpool and Tomkinson Rivers, Arnhem Land, northern Australia, are presented. These were used as the basis of an aerial survey for potential crocodile nesting habitat in coastal wetlands between Smith Point (Cobourg Peninsula) and Gove. General conclusions of the survey are given, and areas in which different types of management could be applied are indicated. Detailed results are lodged with the Australian National Library,Canberra (catalogue No. MS5640).

Growth Rates of Crocodylus Porosus (Reptilia: Crocodilia) From Arnhem Land, Northern Australia.

1978 ◽  
Vol 5 (3) ◽  
pp. 385 ◽  
Author(s):  
GJW Webb ◽  
H Messel ◽  
J Crawford ◽  
MJ Yerbury
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Curve ◽  
Exponential Growth ◽  
Maximum Size ◽  
Northern Australia ◽  
Wet Season ◽  
Second Growth ◽  
Arnhem Land ◽  
Crocodylus Porosus

In C. porosus < 80 cm SVL (snout-vent length), growth rate decreases as body size increases; males grow faster than females, and both sexes grow faster in the wet season than in the dry season. If the exponential growth curve for specimens < 80cm SVL is extrapolated, it underestimates the maximum size of C. porosus. A second growth curve for specimens > 80cm SVL has been derived separately, and the two curves intersect in the vicinity of 70 cm SVL. The size at which C. porosus cease growing seems quite variable and some data indicate a range of 3.9-6.0 m total length for males. The twocurve growth model is thought to reflect an energetic advantage in feeding on large rather than small prey.

Notes on the Young of Blennius galerita, L

1902 ◽  
Vol 6 (3) ◽  
pp. 383-386 ◽  
Author(s):  
L. W. Byrne
Keyword(s):  
The Body ◽  
North Coast ◽  
Pectoral Fins ◽  
The North

No description of the young of this species seems to exist, with the exception of that given by Emery (1) of some examples from Naples.The specimens here described were captured at Newquay, on the north coast of Cornwall, in September, 1898, and have been preserved in formol. They were caught in sandy pools surrounding or surrounded by rocks in the shelter of which they seemed to be fond of lying. When disturbed they darted with considerable rapidity from place to place, and in doing so were seemingly assisted by the large pectoral fins which were carried nearly at right angles to the body by the fish when at rest.

Controls on benthic biomass size spectra in shelf and deep-sea sediments – a modelling study

2011 ◽  
Vol 8 (4) ◽  
pp. 8189-8240 ◽  
Author(s):  
B. A. Kelly-Gerreyn ◽  
T. R. Anderson ◽  
B. J. Bett ◽  
A. P. Martin ◽  
J. I. Kaariainen
Keyword(s):  
Body Size ◽  
The Body ◽  
General Observation ◽  
Size Spectra ◽  
Size Classes ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Wet Weight ◽  
Biomass Spectra

Abstract. Factors controlling biomass distributions in marine benthic organisms (meio- to macro-fauna, 1 μg–32 mg wet weight) were investigated through observations and allometric modelling. Biomass (and abundance) size spectra were measured at three locations: the Faroe-Shetland Channel in the north-east Atlantic (FSC, water depth 1600 m, September 2000); the Fladen Ground in the North Sea (FG, 150 m, September 2000); and the hypoxic Oman Margin (OM, 500 m, September 2002) in the Arabian Sea. Biomass increased with body size through a power law at FG (allometric exponent, b = 0.16) and at FSC (b = 0.32), but less convincingly at OM (b was not significantly different from −1/4 or 0). Our results question the assumption that metazoan biomass spectra are bimodal in marine sediments. The model incorporated 16 metazoan size classes, as derived from the observed spectra, all reliant on a common detrital food pool. All physiological (ingestion, mortality, assimilation and respiration) parameters scaled to body size following optimisation to the data at each site, the resulting values being consistent within expectations from the literature. For all sites, body size related changes in mortality played the greatest role in determining the trend of the biomass size spectra. The body size trend in the respiration rate was most sensitive to allometry in both mortality and ingestion, and the trend in body size spectra of the production: biomass ratio was explained by the allometry in ingestion. Our results suggest that size-scaling mortality and ingestion are important factors determining the distribution of biomass across the meiofauna to macrofauna size range in marine sedimentary communities, in agreement with the general observation that biomass tends to accumulates in larger rather than smaller size classes in these environments.

scholarly journals The Evolution of Primate Body Size: Left-skewness, Maximum Size, and Cope’s Rule

2016 ◽  
Author(s):  
Richard C. Tillquist ◽  
Lauren G. Shoemaker ◽  
Kevin Bracy Knight ◽  
Aaron Clauset
Keyword(s):  
Body Size ◽  
Size Distribution ◽  
Maximum Size ◽  
The Body ◽  
Skewed Distribution ◽  
Primate Species ◽  
Opposite Pattern ◽  
Evolutionary Characteristic ◽  
Initial Tendency ◽  
Cope’S Rule

Body size is a key physiological, ecological, and evolutionary characteristic of species. Within most major clades, body size distributions follow a right-skewed pattern where most species are relatively small while a few are orders of magnitude larger than the median size. Using a novel database of 742 extant and extinct primate species’ sizes over the past 66 million years, we find that primates exhibit the opposite pattern: a left-skewed distribution. We investigate the long-term evolution of this distribution, first showing that the initial size radiation is consistent with plesiadapiformes (an extinct group with an uncertain ancestral relationship to primates) being ancestral to modern primates. We calculate the strength of Cope’s Rule, showing an initial tendency for descendants to increase in size relative to ancestors until the trend reverses 40 million years ago. We explore when the primate size distribution becomes left-skewed and study correlations between body size patterns and climactic trends, showing that across Old and New World radiations the body size distribution initially exhibits a right-skewed pattern. Left-skewness emerged early in Old World primates in a manner consistent with a previously unidentified possible maximum body size, which may be mechanistically related to primates’ encephalization and complex social groups.

The surface swarming of Polybius henslowi [Brachyura: Portunidae]

1968 ◽  
Vol 48 (1) ◽  
pp. 107-111 ◽  
Author(s):  
J. A. Allen
Keyword(s):  
The Body ◽  
Swimming Behaviour ◽  
North Coast ◽  
Reproductive State ◽  
Dense Population ◽  
The North ◽  
Visual Observations

A dense population of Polybius henslowi Leach was recorded at the surface of the sea 15 miles off the north coast of Spain. The depth of water at this point was 1740 m. Visual observations of the swimming behaviour show that Polybius tends to swim with the body facing diagonally and backwards against the current. The space between individuals appears to be maintained deliberately and was never less than 6 ft. during daylight. Measurements show that there are at least two sizegroups present. Females represent 40% of the total of 251 animals collected, and these were at approximately the same reproductive state with the ova maturing. The males are on average 2·3 mm longer than the females. No food was found in the stomach of any of the animals taken.

scholarly journals Biogeographic position and body size jointly set lower thermal limits of wandering spiders

2021 ◽  
Author(s):  
Jérémy Monsimet ◽  
Hervé Colinet ◽  
Olivier Devineau ◽  
Denis Lafage ◽  
Julien Pétillon
Keyword(s):  
Body Size ◽  
Ad Hoc ◽  
Cold Resistance ◽  
The Body ◽  
Freezing Resistance ◽  
Local Adaptations ◽  
The North ◽  
Large Numbers ◽  
Cold Tolerant ◽  
Continental Climate

AbstractMost species encounter large variations in abiotic conditions along their distribution range. Climate, and in particular temperature, varies along clinal gradients, which determines phenotypic plasticity, local adaptations and associated physiological responses of most terrestrial ectotherms, such as insects and spiders. This study aimed to determine how the biogeographic position of populations and the body size of two wandering spiders set their limits of cold (freezing) resistance. Using an ad-hoc design, we sampled relatively large numbers of individuals from four populations of Dolomedes fimbriatus and one population of the sister species Dolomedes plantarius originating from contrasting climatic areas (temperate and continental climate), and compared their supercooling ability as an indicator of cold resistance. Results indicated that spiders from northern (continental) populations had higher cold resistance than spiders from a southern (temperate) populations. Larger spiders had a lower supercooling ability in northern populations. The red-listed and rarest D. plantarius was slightly less cold-tolerant than the more common D. fimbriatus, and this might be of importance in a context of climate change that could imply colder overwintering habitats in the north due to reduced snow cover protection.

Habitat Required for Nesting by Crocodylus porosus (Reptilia : Crocodilidae)

1980 ◽  
Vol 7 (1) ◽  
pp. 149 ◽  
Author(s):  
WE Magnusson
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Angular Deviation ◽  
Northern Australia ◽  
North West ◽  
Nest Sites ◽  
The North ◽  
Nesting Sites ◽  
Crocodylus Porosus

C. povosus in northern Australia does not use all available vegetation for making nests, but those materials that it does use are used in proportion to their availability. Discriminant function analysis was used to quantify the suitability of sites for nesting in terms of vegetation. Crocodiles do not select sites for nests only on the basis of available nesting materials; most nests are made on the north-west banks of rivers (mean direction: 293", angular deviation 61"). There are at least 933 suitable nesting sites for C. porosus on the Liverpool and Tomkinson Rivers. This suggests that the present population of adult crocodiles could increase by a factor of 18 before nest sites became limiting.

Life history and reproductive biology of the invasive amphipod Melita palmata (Amphipoda: Melitidae) in the Mar Chiquita coastal lagoon, Argentina

2006 ◽  
Vol 86 (6) ◽  
pp. 1381-1387 ◽  
Author(s):  
S. Obenat ◽  
E. Spivak ◽  
L. Garrido
Keyword(s):  
Life History ◽  
Body Size ◽  
Population Density ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Lagoon ◽  
Brood Size ◽  
Maximum Size ◽  
The Body ◽  
Invasive Amphipod

The life history and reproductive biology of the gammaridean amphipod Melita palmata was studied in the Mar Chiquita coastal lagoon (Argentina). The animals were collected fortnightly or monthly from Ficopomatus enigmaticus reefs from December 2000 to March 2002. The population density reached a maximum of 1556.67±1560 ind/m3 (mean±SD) in March 2001, decreased dramatically after intense rainfalls in winter 2001, and had a minimum value of 141.67±27.54 ind/m3 (mean±SD) in March 2002. Size differed significantly between sexes. The maximum size of males was 11.5 mm and this was 1.4 times longer than the length of females. The average sex ratio (0.44) did not differ significantly from an expected 1:1 value. Ovigerous females were present from December to March, when the temperature was above 18°C. The body size of ovigerous females ranged from 2.9 to 6.81 mm. There was a positive correlation between the brood size and body length of ovigerous females, and the maximum number of eggs per female was ten. Recruitment took place during the whole breeding season; juveniles recruited at the beginning of the season matured at the end of the same season, those recruited late would probably reach maturity in the following season.

Sign in / Sign up

Export Citation Format

Share Document