Life on the edge: the ecology and life history of the tropidurine iguanid lizard Uranoscodon superciliosum

1990 ◽  
Vol 68 (7) ◽  
pp. 1366-1373 ◽  
Author(s):  
Jeffrey M. Howland ◽  
Laurie J. Vitt ◽  
Pamela T. Lopez
Keyword(s):  
Life History ◽  
Social Interaction ◽  
Sexual Dimorphism ◽  
Small Diameter ◽  
Habitat Specialization ◽  
Large Size ◽  
Tropical Wet Forest ◽  
History Of ◽  
Forest Streams ◽  
Small Forest

An Amazonian population of the iguanid lizard Uranoscodon superciliosum was studied in lowland tropical wet forest in central Pará, Brazil. These nonheliothermic lizards are restricted to densely vegetated habitats near (often over) water, particularly riverbanks and small forest streams, where they utilize small-diameter perches and feed on a wide variety of invertebrates, apparently at the water's edge. They mature at moderate to large size at an age of about 1.5 years. Production of moderate-sized clutches of eggs is seasonal, and reproduction and fat storage both cycle in association with rainfall and flooding. Although they occur in fairly high densities, social interaction is uncommon and sexual dimorphism is not pronounced. The ecology and life history of this lizard seem to be strongly influenced by the unusual habitat specialization.

Electrical Emissions in Gymnotus Carapo and Their Relation To Social Behavior

Behaviour ◽  
1970 ◽  
Vol 37 (1-2) ◽  
pp. 1-14 ◽  
Author(s):  
J.A. Valone
Keyword(s):  
Life History ◽  
Social Interaction ◽  
Social Behavior ◽  
Social Interactions ◽  
Physical Contact ◽  
Postural Responses ◽  
The Social ◽  
History Of ◽  
Electrical Stimuli

Abstract1. The relation between the social behavior and the electrical emissions of Gymnotus carapo is examined. 2. Members of the species Gymnotus carapo approach certain sources of electrical stimuli and, in a statistically significant number of instances, assume a stance parallel to the plane from which the stimuli originate. 3. The approach and postural responses elicited by electrical cues resemble those observed when two fish, placed in the same tank, interact socially. 4. Electrical cues therefore appear to facilitate certain social interactions in Gymnotus carapo. 5. The character of electrical emission in Gymnotus carapo appears to change as a function of certain social interaction: a. Interaction resembling aggression is accompanied by brief increases in the frequency of emission. b. The increases in frequency appear to be linked to thrusting movements. c. Fish interacting with one another appear to lock into a common frequency more often than fish that are not in physical contact with one another. d. During social interaction, one of the two fish is occasionally observed to halt emissions altogether. 6. The exact significance of the social behavior observed in the context of the life history of Gymnotus carapo is unknown.

Life-history traits of a small-bodied coastal shark

2013 ◽  
Vol 64 (1) ◽  
pp. 54 ◽  
Author(s):  
Adrian N. Gutteridge ◽  
Charlie Huveneers ◽  
Lindsay J. Marshall ◽  
Ian R. Tibbetts ◽  
Mike B. Bennett
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Logistic Function ◽  
Early Maturation ◽  
Large Size ◽  
History Of ◽  
Age Model ◽  
Best Fit ◽  
Combined Data

The life histories of small-bodied coastal sharks, particularly carcharhinids, are generally less conservative than those of large-bodied species. The present study investigated the life history of the small-bodied slit-eye shark, Loxodon macrorhinus, from subtropical Hervey Bay, Queensland, and compared this species' biology to that of other coastal carcharhinids. The best-fit age model provided parameters of L∞ = 895 mm total length (TL), k = 0.18 and t0 = –6.3 for females, and L∞ = 832 mm TL, k = 0.44 and t0 = –2.6 for males. For sex-combined data, a logistic function provided the best fit, with L∞ = 842 mm TL, k = 0.41 and α = –2.2. Length and age at which 50% of the population was mature was 680 mm TL and 1.4 years for females, and 733 mm TL and 1.9 years for males. Within Hervey Bay, L. macrorhinus exhibited an annual seasonal reproductive cycle, producing an average litter of 1.9 ± 0.3 s.d. With the exception of the low fecundity and large size at birth relative to maximum maternal TL, the life-history traits of L. macrorhinus are comparable to other small-bodied coastal carcharhinids, and its apparent fast growth and early maturation contrasts that of large-bodied carcharhinids.

The Fine Structure of Primordial Germ Cells of the Rat

1973 ◽  
Vol 31 ◽  
pp. 634-635
Author(s):  
E. M. Eddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Life History ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Germ Cells ◽  
Fibrous Material ◽  
Primordial Germ Cells ◽  
The Other ◽  
Large Size ◽  
History Of

Primordial germ cells are readily recognizable in embryos of the rat due to their large size, generally rounded shape and prominent nuclei with uniformly dispersed heterochromatin. They often have blunted pseudopodal processes at one end and small ruffles or trailing processes at the other, characteristics expected from their known ameboid activity- and migratory abilities. Also, the cytoplasm is rich in polyribosomes and contains a modest amount of rough endoplasmic reticulum and the mitochondria are frequently larger and less dense than those of adjacent somatic cells.In addition to these general characteristics, there are features unique to germ cells which allow them to be identified with certainty. These are: 1) small vesicles containing an irregular, dense core and 2) discrete accumulations of fibrous material known as nuage. Both of these features are present in other species and at other times in the life history of germ cells. The dense-cored vesicles have been noted in fetal and early postnatal mouse oogonia and oocytes, and in hamster and rabbit oocytes.

Sexual dimorphism and life history of Keichousaurus hui (Reptilia: Sauropterygia)

2009 ◽  
Vol 29 (2) ◽  
pp. 401-408 ◽  
Author(s):  
Yen-Nien Cheng ◽  
Robert Holmes ◽  
Xiao-Chun Wu ◽  
Noel Alfonso
Keyword(s):  
Life History ◽  
Sexual Dimorphism ◽  
History Of

scholarly journals Life history of Tendaguru sauropods as inferred from long bone histology

Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 103-112 ◽  
Author(s):  
P. M. Sander
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Sexual Maturity ◽  
Upper Jurassic ◽  
Bone Histology ◽  
Long Bone ◽  
Large Mammals ◽  
Growth Series ◽  
History Of

Abstract. Sauropod dinosaurs present exceptional challenges in understanding their biology because of their exceptional body size. One of these, life history, can be inferred from the histology of their bones. For this purpose, the diverse sauropod assemblage of the Upper Jurassic Tendaguru beds was sampled with a new coring method which provided unprecented access to and insights into sauropod bone histology. Growth series of humeri and femora as well as long growth records from single bones suggest that all four sauropod taxa are characterized by continued growth after sexual maturity but that growth was determinate. Fibrolamellär bone is dominant in the samples, indicating that the bones of the Tendaguru sauropods grew at rates comparable to those of modern large mammals. The growth pattern of these sauropods thus combines typically reptilian traits with typically mammalian traits. In the details of their bone histology, the Tendaguru sauropod taxa show considerable variation which reflects life history. In addition, Barosaurus exhibits probable sexual dimorphism in bone histology. Das Verständnis der Biologie der sauropoden Dinosaurier wird durch ihre enorme Körpergröße außerordentlich erschwert. Allerdings kann ein Aspekt, die Lebensgeschichte, anhand der Histologie ihrer Knochen untersucht werden. Zu diesem Zweck wurde die diverse Sauropoden-Vergesellschaftung der oberjurassischen Tendaguru-Schichten beprobt, und zwar mit einer neuartigen Kernbohrmethode, die einen herausragenden Zugang und Einblick in die Knochenhistologie der Sauropoden ermöglichte. Wachstumsserien von Humeri und Femora sowie umfassende Überlieferungen des Wachstums von Individuen anhand einzelner Knochen machen es wahrscheinlich, daß alle vier Sauropoden-Taxa der Tendaguru-Schichten durch ein auch nach der Geschlechtsreife anhaltendes Wachstum gekennzeichnet waren. Allerdings ging das Wachstum nicht bis zum Tode des Tieres weiter, sondern kam bei einer etwas variablen Maximalgröße zum Stillstand. Fibrolamellärer Knochen ist der vorherrschende Knochentyp in den Proben, was anzeigt, daß die Tendaguru-Sauropoden mit für Säugetieren typische Raten wuchsen. Die Tendaguru-Sauropoden kombinerten also ein für Reptilien typisches Muster des Wachstums, nämlich nach der Geschlechtsreife anhaltendes Wachstum, mit für Säuger typischen Raten des Wachstums. Die verschiedenen Sauropoden-Taxa zeigen erstaunliche Unterschiede in den Details ihrer Knochenhistologie, die Unterschiede in der Lebensgeschichte belegen. Bei Barosaurus scheint außerdem ein Geschlechtsdimorphismus in der Histologie der Langknochen vorzukommen. doi:1002/mmng.1999.4860020107

Descriptions and Life History of Melanolophia imitata (Walker) (Lepidoptera: Geometridae)

1962 ◽  
Vol 94 (6) ◽  
pp. 594-605 ◽  
Author(s):  
David Evans
Keyword(s):  
Life History ◽  
Large Size ◽  
Forest Insects ◽  
Large Numbers ◽  
Migratory Movement ◽  
Pale Colour ◽  
History Of ◽  
Late Evening

Melanolophia imitata (Walker) has been colloquially referred to as the green-striped forest looper, in reference to its appearance and habitat. The spring-flying adults and the consistently large numbers of larvae attract considerable attention annually. Although the moths evince little migratory movement, their comparatively large size and pale colour, in association with their quantity, combine to create the basis for occasional alarming reports of forest insects. It is not infrequent to hear of clouds of moths scattering about a forest traveller and viewed throughout the woods. Ordinarily the adults fly during late evening, and are less attracted to light than many moths.

Life in the trees: the ecology and life history of Kentropyx striatus (Teiidae) in the lavrado area of Roraima, Brazil, with comments on the life histories of tropical teiid lizards

1992 ◽  
Vol 70 (10) ◽  
pp. 1995-2006 ◽  
Author(s):  
Laurie J. Vitt ◽  
Celso Morato de Carvalho
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Prey Size ◽  
Annual Rainfall ◽  
Activity Period ◽  
Body Temperatures ◽  
Wet Season ◽  
Reproductive Characteristics ◽  
History Of

The ecology and life history of the tropical teiid lizard Kentropyx striatus were studied in a grassland of northern Brazil, the lavrado area. The area, located nearly at the equator, experiences a prolonged dry season with a wet season extending from May to September. Total annual rainfall averages 1750 mm. Lizards were nonrandomly distributed among habitat patches and microhabitats. Most individuals were in trees and shrubs surrounding temporary and permanent water. Most individuals were observed active during late morning, the time period during which feeding and social interactions were observed. Lizards bask to achieve active body temperatures averaging 35.7 ± 0.23 °C. Body temperature is correlated with both substrate and air temperatures; foraging lizards maintained higher temperatures than basking lizards regardless of whether they were in sun, and lizards sampled when there was cloud cover had lower body temperatures than those sampled when sun was available. Females reach sexual maturity at 74 mm snout–vent length (SVL), produce 3–9 eggs per clutch, reproduce more than once per season, and commence reproduction during the wet season. Lizards hatch from eggs at 31 mm SVL. Maturity appears to be reached in 1 year or less. Overall, female reproductive characteristics are similar to those of other tropical teiid lizards that have been studied, with body size explaining much of the variance in reproductive characteristics across species. There is pronounced sexual dimorphism, with males larger in body size as well as certain other characteristics independent of body size. Sexual dimorphism appears to be a consequence of sexual selection. The diet is varied, but is dominated volumetrically by frogs, eruciform larvae, and spiders. Lizard body size accounted for only 5.5% of the variance in prey size and there was no difference in prey size due to sex. The occurrence of frogs and lizards in K. striatus stomachs suggests that teiid lizards may influence the structure of lizard and frog assemblages. The similarity of K. striatus to other studied tropical teiids in reproductive characteristics, morphology, activity period, activity temperatures, and diet underscore the conservative nature of the ecology of teiid lizards, presumably a consequence of their mode of prey acquisition.

scholarly journals Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis

2008 ◽  
Vol 4 (6) ◽  
pp. 719-723 ◽  
Author(s):  
Luis M Chiappe ◽  
Jesús Marugán-Lobón ◽  
Shu'an Ji ◽  
Zhonghe Zhou
Keyword(s):  
Life History ◽  
Sexual Dimorphism ◽  
Exponential Growth ◽  
Growth Stage ◽  
Sexual Size Dimorphism ◽  
Growth Patterns ◽  
Morphometric Study ◽  
Size Dimorphism ◽  
Caudal Vertebrae ◽  
History Of

Confuciusornis sanctus stands out among the remarkable diversity of Mesozoic birds recently unearthed from China. Not only is this primitive beaked pygostylian (birds with abbreviated caudal vertebrae fused into a pygostyle) much more abundant than other avian taxa of this age but differences in plumage between specimens—some having a pair of long stiff tail feathers—have been interpreted as evidence for the earliest example of sexual dimorphism in birds. We report the results of a multivariate morphometric study involving measurements of more than 100 skeletons of C. sanctus . Our analyses do not show any correlation between size distribution and the presence or absence of blade-like rectrices (tail feathers), thus implying, that if these feathers are sexual characters, they are not correlated with sexual size dimorphism. Our results also provide insights into the taxonomy and life history of confuciusornithids, suggesting that these birds may have retained ancestral dinosaurian growth patterns characterized by a midlife exponential growth stage.

scholarly journals Life-history features of a rapids-dwelling loricariid catfish from Atlantic forest streams, Brazil

2016 ◽  
Vol 16 (2) ◽  
Author(s):  
Marcelo Fulgêncio Guedes Brito ◽  
Henrique Lazzarotto ◽  
Erica Pellegrini Caramaschi
Keyword(s):  
Spatial Distribution ◽  
Life History ◽  
Sexual Dimorphism ◽  
Natural Habitat ◽  
Lower Surface ◽  
River Channel ◽  
Epidermal Growth ◽  
The Mean ◽  
Forest Streams ◽  
Spawning Sites

Spatial distribution, suitable spawning sites, and sexual dimorphism were investigated in armored catfish Neoplecostomus microps in the Macaé River from March 2004 to March 2005. Individuals of N. microps (n=290) were limited to fast-flowing stretches, and the distribution was related to ontogenetic development. Larvae in post-flexion occurred in the marginal vegetation, and adults only in gaps between boulders and stones in the river channel. Juveniles occurred in both environments. Spawns were found in the natural habitat in rapid stretches, with the eggs attached to the lower surface of stones in openings formed in the riverbed. The number of eggs per stone ranged from 62 to 375, with significant differences among the mean sizes of the eggs. Sexual dimorphism was noticed to N. microps. The anal and urogenital papillae are separated in males and merged in females and there is an epidermal growth along the pectoral-fin spine of males.

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