scholarly journals Postembryonic development, paedomorphosis, secondary sexual dimorphism and population structure of a newFlorarctusspecies (Tardigrada, Heterotardigrada)

2016 ◽  
Vol 178 (4) ◽  
pp. 871-877 ◽  
Author(s):  
Jesper Guldberg Hansen ◽  
Reinhardt Møbjerg Kristensen ◽  
Aslak Jørgensen ◽  
Gianluca Accogli ◽  
Rossanna D'Addabbo ◽  
...  
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Postembryonic Development ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Do secondary sexual dimorphism and female intolerance to drought influence the sex ratio and extinction risk of Taxus baccata?

Plant Ecology ◽  
2008 ◽  
Vol 200 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Grzegorz Iszkuło ◽  
Anna K. Jasińska ◽  
Marian J. Giertych ◽  
Adam Boratyński
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Extinction Risk ◽  
Taxus Baccata ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

scholarly journals Extreme secondary sexual dimorphism in the genus Florarctus (Heterotardigrada: Halechiniscidae)

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Piotr Gąsiorek ◽  
David Møbjerg Kristensen ◽  
Reinhardt Møbjerg Kristensen
Keyword(s):  
Sexual Dimorphism ◽  
Pacific Ocean ◽  
Barrier Reef ◽  
Queensland Museum ◽  
The Pacific ◽  
Secondary Sexual Dimorphism ◽  
The Pacific Ocean ◽  
A New Species ◽  
Lines Of Evidence ◽  
Secondary Sexual

AbstractSecondary sexual dimorphism in florarctin tardigrades is a well-known phenomenon. Males are usually smaller than females, and primary clavae are relatively longer in the former. A new species Florarctus bellahelenae, collected from subtidal coralline sand just behind the reef fringe of Long Island, Chesterfield Reefs (Pacific Ocean), exhibits extreme secondary dimorphism. Males have developed primary clavae that are much thicker and three times longer than those present in females. Furthermore, the male primary clavae have an accordion-like outer structure, whereas primary clavae are smooth in females. Other species of Florarctus Delamare-Deboutteville & Renaud-Mornant, 1965 inhabiting the Pacific Ocean were investigated. Males are typically smaller than females, but males of Florarctus heimi Delamare-Deboutteville & Renaud-Mornant, 1965 and females of Florarctus cervinus Renaud-Mornant, 1987 have never been recorded. The Renaud-Mornant collection was re-examined, and type series were analysed. Florarctus heimi and F. cervinus were always found together in the coralline sand of Heron Island (Great Barrier Reef). The animals were kept alive and surveyed in the laboratory of the Queensland Museum. All studied individuals of the larger F. heimi (up to ca. 400 μm) were females, and all adults of the smaller F. cervinus (about 170 μm) were males. Males of F. cervinus were observed mating with females of F. heimi. Following those morphological and behavioural lines of evidence, we propose that F. cervinus is a junior synonym of F. heimi. Based on the discovery of dimorphism in F. bellahelenae sp. nov. and the strong sex-related morphological disparities in F. heimi, we suggest that extreme secondary dimorphism may be present in other florarctin arthrotardigrades.

scholarly journals Identificación individual de tepezcuincle (Cuniculus paca) mediante el uso de huellas.

2009 ◽  
Vol 13 (1) ◽  
pp. 34 ◽  
Author(s):  
Rusby Guadalupe Contreras–Díaz ◽  
Antonio Santos–Moreno ◽  
Ana María Alfaro ◽  
Martín Pérez–Lustre
Keyword(s):  
Sexual Dimorphism ◽  
Principal Component ◽  
Wilcoxon Test ◽  
Individual Identification ◽  
Secondary Sexual Dimorphism ◽  
Para Determinar ◽  
Del Rio ◽  
San Martín ◽  
Plaster Casts ◽  
Secondary Sexual

Resumen: El presente estudio tuvo como objetivo diseñar un método para la identificación entre individuos de tepezcuintle (Cuniculus paca), mediante las características de sus huellas, así como probar su eficiencia en campo.  Se obtuvieron moldes de yeso de las huellas de 11 individuos en cautiverio a los cuales se les tomaron diferentes medidas (seis lineales y un ángulo).  Para determinar si existe dimorfismo sexual secundario en cada una de las variables, se aplicó la prueba no paramétrica de Wilcoxon.  Se realizó una estandarización de los datos para así emplear un Análisis de Componentes Principales (ACP) con matriz de variaza-covarianza.  Para llevar a cabo el método en campo se obtuvieron moldes de huellas en un transecto (1 km) establecido en los márgenes del río Soyolapan, en San Martín Soyolapan, Oaxaca, durante dos periodos de colecta de cinco días cada uno en los meses de diciembre de 2006 y enero de 2007.  No encontramos diferencias estadísticamente significativas entre las huellas de machos y hembras, por lo que se concluye que no hay dimorfismo sexual secundario en las huellas de tepezcuintle.  Mediante el ACP es posible llegar a identificar el 61 % de los individuos, utilizando los dos primeros Componentes Principales (CP1 y CP2).  Al aplicar el método en San Martín Soyolapan se estimó una abundancia de cinco individuos.Palabras clave: Identificación individual, tepezcuintle, huellas, Oaxaca.Abstract:The present study had as an objective to design a method to identify individual pacas (Cuniculus paca) using their track characteristics and to apply it in the field. Plaster casts were obtained from the tracks of captive individual pacas, and six linear measures and one angle were taken. To determine if secondary sexual dimorphism exists, a Wilcoxon test was applied to each variable.  A Principal Component Analysis (PCA) was applied over a covariance matrix of standardized data.  For the application of the method in the field, plaster casts were obtained in a 1 km transect established at the edge of the Soyolapan river, in San Martín Soyolapan, Santiago Comaltepec, Oaxaca, during two periods of five days each, in December 2006 and January 2007.  We found no differences between male and female tracks, so we concluded that secondary sexual dimorphism in paca tracks does not exist.  By means of PCA it was possible to identify 61 % of the individuals analyzed.  When applying this method an abundance of five individuals was estimated for the San Martín Soyolapan site.Key words: Individual identification, paca, tracks, Oaxaca. 

scholarly journals Two new species of Characidium Reinhardt (Characiformes: Crenuchidae) from northeastern Brazilian coastal drainages

2015 ◽  
Vol 13 (3) ◽  
pp. 487-498 ◽  
Author(s):  
Angela M. Zanata ◽  
Priscila Camelier
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Posterior Margin ◽  
The Other ◽  
Caudal Fin ◽  
Two New Species ◽  
Black Blotch ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Two new species of Characidium , onefrom the rio Pardo basin, and anotherfrom the rio Paraguaçu basin, Bahia, Brazil, are described. The first new speciesis distinguished from its congeners by having conspicuous black vertical traces on body, formed by the concentration of melanophores along posterior margin of scales. The species further differs from most congeners by the presence of a conspicuous 3-shaped black blotch on the caudal fin and isthmus not covered by scales. The other new species is distinguished from congeners by having irregular dark blotches on dorsum alternating elongation to one or the other side of body, usually not connected to lateral blotches. The species can be further characterized by the absence of conspicuous blotches or bars on fins and the presence of secondary sexual dimorphism, such as pelvic fins of mature males longer than in females and with bony hooks.

Secondary sexual dimorphism in a dioecious tree: a matter of inter-plant variability?

Flora ◽  
2020 ◽  
Vol 266 ◽  
pp. 151595
Author(s):  
Giovana María Galfrascoli ◽  
Ana Calviño
Keyword(s):  
Sexual Dimorphism ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Systematic studies of deer mice, Peromyscus maniculatus Wagner (Cricetidae, Rodentia): analysis of age and secondary sexual variation in morphometric characters

1983 ◽  
Vol 61 (11) ◽  
pp. 2618-2628 ◽  
Author(s):  
H. S. Koh ◽  
R. L. Peterson
Keyword(s):  
Sexual Dimorphism ◽  
Peromyscus Maniculatus ◽  
Tooth Wear ◽  
The United States ◽  
Deer Mice ◽  
Age Classes ◽  
Morphometric Characters ◽  
Age Variation ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Age variation and secondary sexual dimorphism in three external and 27 cranial characters of wild-taken deer mice, Peromyscus maniculatus Wagner, from the United States and Canada were analyzed statistically. Specimens were classified as subadults, young adults, middle-aged adults, and old adults based on pelage colour and tooth wear. Variation among the four age-classes was evident. Significant secondary sexual dimorphism between sexes of the same age-class was not evident. Univariate and multivariate phenetic analyses using specimens of the comparable age-classes are necessary to clarify the systematic status of P. maniculatus.

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