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1.
Intersexuality in sheep is rare, with the freemartin anomaly being the most common. We describe here a true hermaphrodite in a wild sheep. An F(1) wild sheep ewe of Argali-mouflon X Mexican desert bighorn breeding was bred to an F(1) ram of the same breeding. A single lamb was born with the external appearance of a normal female. The lamb grew faster than its female cohorts, and by 6 months of age exhibited the aggressive behavior, size, coloration and horn development associated with males. Phenotypically, the intersex had female external genitalia with an enlarged clitoris. A human chorionic gonadotrophin (hCG) response test was performed when the intersex was 1-year-old and serum testosterone, progesterone and estradiol levels were compared to the response of a normal female and male of similar age and breeding. An exploratory celiotomy revealed two gonadal-like structures associated with a female reproductive tract. Histopathology of the structures revealed spermatogenically inactive testicular vessels and ovarian tissue with primary follicles. The reproductive tract was complete with two uterine horns and a cervix. The intersexuality is attributed to an XX/XXY mosaic.  相似文献   

2.
Genitalia are among the fastest evolving morphological traits as evidenced by their common function as diagnostic traits in species identification. Even though the main function of genitalia is the successful transfer of spermatozoa, the presence of diverse structures that are obviously not necessary for this suggests that genitalia are a target of sexual selection. The male genitalia of many spider species are extremely complex and equipped with numerous sclerites, plates and spines whose functions are largely unknown. Selection on male genitalia may be particularly strong in sexually cannibalistic spiders, where mating success of males is restricted to a single female. We investigated the copulatory mechanism of the sexually cannibalistic orb weaving spider Argiope bruennichi by shock freezing mating pairs and revealed a complicated interaction between the appendices and sclerites that make up the male gonopods (paired pedipalps). The plate that covers the female genital opening (scape) is secured between two appendices of the male genital bulb, while three sclerites that bear the sperm duct are unfolded and extended into the female copulatory opening. During copulation, females attack and cannibalise the male and males mutilate their genitalia in about 80% of cases. Our study demonstrates that (i) genital coupling is largely accomplished on the external part of the female genitalia, (ii) that the mechanism requires an interaction between several non-sperm-transferring structures and (iii) that there are two predetermined breaking points in the male genitalia. Further comparative work on the genus Argiope will test if the copulatory mechanism with genital mutilation indeed is an adaptation to sexual cannibalism or if cannibalism is a female counter adaptation to male monopolisation through genital plugging.  相似文献   

3.
Despite claims that genitalia are among the fastest evolving phenotypes, few studies have tested this trend in a quantitative and phylogenetic framework. In systems where male and female genitalia coevolve, there is a growing effort to explore qualitative patterns of evolution and their underlying mechanisms, but the temporal aspect remains overlooked. An intriguing question is how fast male and female genitalia may change in a coevolutionary scenario. Here, we apply a series of comparative phylogenetic analyses to reveal a scenario of correlated evolution and to investigate how fast male and female external, nonhomologous and functionally integrated genitalia change in a group of stink bugs. We report three findings: the female gonocoxite 8 and the male pygophore showed a clear pattern of correlated evolution, both genitalia were estimated to evolve much faster than nongenital traits, and rates of evolution of the male genitalia were twice as fast as the female genitalia. Our results corroborate the widely held view that male genitalia evolve fast and add to the scarce evidence for rapidly evolving female genitalia. Different rates of evolution exhibited by males and females suggest either distinct forms or strengths of selection, despite their tight functional integration and coevolution. The morphological characteristics of this coevolutionary trend are more consistent with a cooperative adjustment of the genitalia, suggesting a scenario of female choice, morphological accommodation, lock‐and‐key or some combination of the three.  相似文献   

4.
5.
Pregnancy terminated for a severe oligoamnios and renal dysplasia. Chromosomal, gonadal, internal genitalia sexes are female. There is a cloacal dysgenesis, with caudal appendice and hypoplastic external genitalia of male type. Single umbilical artery and congenital cardiac malformation (complete atrio ventricular communication) are associated. Embryopathologic explanation for this female pseudo-hermaphroditism is proposed.  相似文献   

6.
Sensilla on the male and female external genitalia of the carabid beetle, Carabus (Ohomopterus) dehaanii dehaanii Chaudoir, were investigated with scanning electron microscopy. The investigation for female genitalia was conducted on the coxites and styli. As a result, 4 types of sensilla were distinguished. In male, a total of 6 types of sensilla were identified on the aedeagus. The external morphology and distribution pattern of each type of the sensilla in both sexes were described. Results are expected to provide a ground work for future research on the phylogenetic study of the genus Carabus and the comparative ultrastructure or behavior in the carabid beetle.  相似文献   

7.
A new species of the genus Ronderosia Cigliano 1997 is described. Color illustrations of the female and male, drawings of female and male external genitalia as well as drawings of its phallic structures and photographs of the chromosomes are included.  相似文献   

8.
Hangingflies are unique for the male providing a nuptial gift to the female during mating and taking a face-to-face hanging copulation with the female. Their male genitalia are peculiar for an extremely elongated penisfilum, a pair of well-developed epandrial lobes (9th tergum), and a pair of degenerated gonostyli. However, the co-evolution of their face-to-face copulation behavior and the male genitalia has rarely been studied hitherto. In this paper the mating behavior of the hangingfly Bittacus planus Cheng, 1949 was observed under laboratory conditions, and the morphology of the male and female external genitalia was investigated using light and scanning electron microscopy. The male provides an insect prey as a nuptial gift to the female in courtship and mating process, and commits a face-to-face copulation. During copulation, the male abdomen twists temporarily about 180° to accommodate their face-to-face mating position. The aedeagal complex has an extremely elongated penisfilum, corresponding to the elongated spermathecal duct of the female. The well-developed epandrial lobes serve as claspers to grasp the female subgenital plate during copulation, replacing the function of gonostyli, which are greatly reduced in Bittacidae. The modified proctiger assists the penisfilum to stretch and to enter into the female spermathecal duct. The possible reasons why this species might mate face-to-face are briefly discussed.  相似文献   

9.
【目的】利用扫描电子显微镜(scanning electron microscopy, SEM)观察屋尘螨Dermatophagoides pteronyssinus颚体、 躯体、 外生殖器及足等的形态结构。【方法】从床尘、 枕尘中采集屋尘螨, 分离出雌雄成螨, 在体视显微镜下清洗处理活螨后, 用SEM观察其外部形态特征。【结果】SEM照片显示, 屋尘螨螯肢钳状, 须肢扁平; 体表具细密皮纹, 似指纹状, 纹间距小于2 μm。外生殖器位于腹面正中, 雌螨为产卵孔, 雄螨生殖孔具1对叶状生殖盖。肛门呈纵行裂孔, 雄螨具2个肛吸盘。雌螨足跗节末端各具爪垫1个, 雄螨跗节Ⅳ具2个吸盘。【结论】本研究观察结果为尘螨鉴定提供了更多依据。  相似文献   

10.
Sexual size dimorphism (SSD) can strongly influence the evolution of reproductive strategies and life history. If SSD is extreme, and other characters (e.g., genitalic size) also increase with size, then functional conflicts may arise between the sexes. Spiders offer an excellent opportunity to investigate this issue because of their wide range of SSD. By using modern phylogenetic methods with 16 species of orb-weaving spiders, we provide strong evidence for the "positive genitalic divergence" model, implying that sexual genitalic dimorphism (SGD) increases as SSD increases. This pattern is supported by an evolutionary mismatch between the absolute sizes of male and female genitalia across species. Indeed, our findings reveal a dramatic reversal from male genitalia that are up to 87x larger than female genitalia in size-monomorphic species to female genitalia that are up to 2.8x larger in extremely size-dimorphic species. We infer that divergence in SGD could limit SSD both in spiders, and potentially in other taxa as well. Further, male and female body size, as well as male and female genitalia size, are decoupled evolutionarily. Finally, we show a negative scaling (hypoallometry) of male and female genitalic morphology within sexes. Evolutionary forces specific to each sex, such as larger female size (increased fecundity) or smaller male size (enhanced mate-searching ability), may be balanced by stabilizing selection on relative genitalic size.  相似文献   

11.
Symmetry is such a conspicuous feature of life that asymmetries draw our immediate attention. While not uncommon in bilateral organisms in general, asymmetry in spiders is rare. Here I report the first case of antisymmetry in external female genitalia in spiders, in the new genus Asygyna (Theridiidae: Araneae) from Madagascar. In the nearly 39 000 species of spiders described to date, the external structure of the female genitalia is symmetric. In entelegyne spiders paired external copulatory openings each lead to an internal copulatory duct, whose roughly symmetrical trajectories terminate in paired receptacles, the spermathecae. In Asygyna , here exemplified by two new species, A. huberi and A. coddingtoni , laterality is evident in the internal and external female genitalia. A single copulatory opening leads (either to the left or right depending on the individual) to a single copulatory duct with a distinctly asymmetric trajectory. The duct splits terminally shortly before entering the two spermathecae. The males are symmetric, but possibly only one palp can be used in copulation with each female. If adaptive, the selective forces behind this asymmetry are perplexing, as male access to females seems reduced. However, if males are plentiful, asymmetry may benefit the female by reducing insertion times and thus shortening copulation time, and by tightening her control over which males sire her offspring. Asygyna has a range of other bizarre sex-related morphologies, including prosomal pits and a well developed stridulatory mechanism in both sexes, a male proboscis, and simplified palps. A phylogenetic analysis, including 63 taxa and 242 morphological characters, places Asygyna in Pholcommatinae, sister to the enigmatic genus Carniella .  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 211–232.  相似文献   

12.
Nesotriatoma confusa sp. nov. (Hemiptera, Reduviidae, Triatominae) is described based on specimens from Cuba. From one male, one female, and eleven nymphs of a then‐undescribed species of Nesotriatoma collected in Cuba, a colony was formed and its specimens were used to describe N. confusa sp. nov. Characters were observed on the head, thorax, abdomen, female external genitalia, and male genitalia with optical microscopy and scanning electron microscopy. We concluded that N. bruneri (Usinger, 1944 ) was indeed a synonym of N. flavida (Neiva, 1911 ) as previously proposed.  相似文献   

13.
Our study – the first of its kind within Histeridae (Coleoptera) – deals with the female genitalia in the subfamily Saprininae, with respect to their variation and utility for phylogenetic reconstruction. Morphology of female genitalia (chiefly characters of the spermatheca, and variation of the gonocoxites, articulating sclerites and gonostyli) is herein described and depicted. We perform parsimony‐based morphological phylogenetic analyses of Saprininae using combined datasets that comprise somatic, male and female genitalia characters. We assess phylogenetic utility of female genital characters and test for their correlation with male genital characters. We found that female genitalia are generally moderately informative for phylogenetic reconstruction. The somatic and male genitalia characters (on average) possess higher phylogenetic signal; female genitalia provide better support and diagnoses for particular clades (emphasizing their importance for systematics), in which the evolution of female genitalia can be linked to environmental factors imposed by the mode of life. Regardless of the degree of informativeness, structures of female genitalia represent an additional interesting and important source of information for systematics and taxonomy. We did not find any evidence of correlated evolution between male and female genitalia.  相似文献   

14.
The mammalian external genitalia are specialized appendages for efficient copulation, internal fertilization and display marked morphological variation among species. In this paper, we described the embryonic development of mouse genital tubercle (GT), an anlage of the external genitalia utilizing the scanning electron microscope (SEM) analysis. It has been shown that the Distal Urethral Epithelium (DUE) may fulfill an essential role in the outgrowth control of the GT. Our present SEM analysis revealed a small distal protrusion at the tip of the GT of normal embryos as well as some morphological differences between male and female embryonic external genitalia. Previous analysis shows that the teratogenic dose of Retinoic Acid (RA) induces a drastic marformation of the urethral plate, but not gross abnormalities for GT outgrowth. Interestingly, a small distal protrusion at the tip of GT was clearly observed also after RA treatement. Furthermore, we showed that treatment with anti-androgen flutamide resulted in the demasculinization of the GT in males. The unique character of GT development and the sexual dimorphism are discussed.  相似文献   

15.
通过对耳蛱蝶Eulaceura osteria与爻蛱蝶Herona marathus的成虫形态特征、雌雄外生殖器解剖特征、地理分布的比较研究,并结合闪蛱蝶亚科系统发育分析结果,表明耳蛱蝶与爻蛱蝶成虫外部形态特征及雌雄外生殖器解剖特征存在许多相同之处,地理分布相互重叠;系统发育分析结果该2种并入同一支系,互为姊妹群关系;建议将耳蛱蝶归入爻蛱蝶属中,同时将耳蛱蝶属作为爻蛱蝶属的异名处理。  相似文献   

16.
Xp-duplications with and without sex reversal   总被引:5,自引:0,他引:5  
Duplications in Xp including the DSS (dosage sensitive sex reversal) region cause male to female sex reversal. We investigated two patients from families with Xp duplications. The first case was one of two sisters with karyotype 46,XY, der(22), t(X;22)(p11.3;p11)mat and unambiguous female genitalia. The living sister was developmentally retarded, and showed multiple dysmorphic features and an acrocallosal syndrome. The second case was a boy with a maternally inherited direct duplication of Xp21.3-pter with the breakpoint close to the DSS locus. He had multiple abnormalities and micropenis, but otherwise unambiguous male genitalia. We performed quantitative Southern blot analysis with probes from Xp22.13 to p21.2 to define the duplicated region. Clinical, cytogenetic, and molecular data from both patients were compared with those of previously reported related cases. A comparison of the extragenital symptoms revealed no differences between patients with or without sex reversal. In both cases, the symptoms were non-specific. Among 22 patients with a duplication in Xp, nine had unambiguous female genitalia and a well-documented duplication of the DSS region. Two patients with duplication of DSS showed ambiguous external genitalia. From these data, we conclude that induction of testicular tissue may start in these patients, but that the type of genitalia depends on the degree of subsequent degeneration by a gene in DSS.  相似文献   

17.
18.
Most birds have simple genitalia; males lack external genitalia and females have simple vaginas. However, male waterfowl have a phallus whose length (1.5->40 cm) and morphological elaborations vary among species and are positively correlated with the frequency of forced extra-pair copulations among waterfowl species. Here we report morphological complexity in female genital morphology in waterfowl and describe variation vaginal morphology that is unprecedented in birds. This variation comprises two anatomical novelties: (i) dead end sacs, and (ii) clockwise coils. These vaginal structures appear to function to exclude the intromission of the counter-clockwise spiralling male phallus without female cooperation. A phylogenetically controlled comparative analysis of 16 waterfowl species shows that the degree of vaginal elaboration is positively correlated with phallus length, demonstrating that female morphological complexity has co-evolved with male phallus length. Intersexual selection is most likely responsible for the observed coevolution, although identifying the specific mechanism is difficult. Our results suggest that females have evolved a cryptic anatomical mechanism of choice in response to forced extra-pair copulations.  相似文献   

19.
Sex-chromosomal chimerism (XX/XY) was described in a pair of bovine like-sexed male twins. One of the twins showed malformed external genitalia, and the other was phenotypically normal. It is proposed that sex-chromosomal chimerism is associated with a choriovascular anastomosis between like-sexed twins examined and "female fetus" which may be overlooked at parturition.  相似文献   

20.
The highly masculinized genitalia of female spotted hyenas Crocuta crocuta is unique among mammals: Crocuta have no external vagina so urination, penile intromission and parturition take place through the clitoris, which mimics a fully erectile male penis. Among hyenids, virilization of external female genitalia has previously been observed only in Crocuta, so functional explanations of masculinization have focused on aspects of social ecology unique to the species. Here we first show that the striped hyena Hyaena hyaena exhibits both unusual similarity in male and female androgen concentrations and transient genital anomalies characterized by a convergence in genital appearance among young males and females. We then evaluate hypotheses regarding the evolution of genital masculinization in the Hyaenidae and other taxa. Hyaena are behaviorally solitary, so discovery of unusual genital development patterns in this species does not support any current evolutionary models for masculinization in Crocuta, which all rely on the trait originating within a highly social species. Some hypotheses can be modified so that masculinization in Crocuta represents an extreme elaboration of a preexisting trait, shared as a homology with Hyaena.  相似文献   

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