Genital system anatomy and development of Ovatella myosotis by three‐dimensional computer visualization

Adult anatomy as well as organogenesis of the genital system of the ellobiid pulmonate Ovatella myosotis is investigated in detail by means of serial sectioning and three‐dimensional computer reconstruction and visualization. From the middle portion of the adult, which has four nidamental glands, a spermoviduct leads to a common genital aperture. From here two separate structures, the vas deferens and a groove on the body surface, lead anteriorly. The latter is termed the egg groove because it carries the egg ribbon anteriorly, a function that is recognized here for the first time in the Ellobiidae. The evolution of this structure is discussed. In development, the organ system arises from four separate anlagen: (1) the ovotestis anlage, (2) the pallial anlage giving rise to the hermaphrodite duct, fertilization pouch–spermatheca complex, nidamental glandular complex and spermoviduct, (3) the bursa copulatrix anlage and (4) the anlage of the copulatory organ, vas deferens and egg groove. This development mode strongly resembles that of the siphonariid Williamia radiata, supporting its interpretation as a plesiomorphy in Pulmonata. Similarities in development of primitive pulmonates and evolution in gastropods lead to the assumption that ontogenesis of this organ system reflects evolution to some degree.     

The functional significance of the spermatophore and the fate of spermatozoa in the genital tract of Helix pomatia (Gastropoda: Stylommatophora)

In the Helicidae and in some other Stylommatophora the sperm are transferred in a spermatophore, even though there appears to be no need for protection of the sperm during the transfer. The function of the spermatophore and related problems concerning the genital organs of Helix pomatia were studied by means of morphological and experimental methods.
The spermatophore is necessary to ensure the functioning of the female system at copulation. Its structure allows some of the spermatozoa it contains to escape through its tail canal, pass from the stalk of the bursa and reach the spermatheca by way of the oviduct; but most of the sperm pass into the bursa copulatrix and are destroyed, as is also the fate of the spermatophore. Only foreign sperm are stored in the spermatheca.
Spermiogenesis was found to take place throughout the whole summer. At intervals some sperm are released from the hermaphrodite duct and are conducted via the spermoviduct and oviduct to the bursa, where they are digested. The two grooves of the spermoviduct are functionally separated only for a few minutes at actual copulation, when sperm are conducted to the copulatory organs, where the spermatophore is being formed.     

Anatomical and histological structure of the spermoviduct in the ovoviviparous snail Ruthenica filograna (Pulmonata,Clausiliidae)

The spermoviduct is a multifunctional part of the hermaphroditic reproductive system of stylommatophoran pulmonates. In this study, the anatomical and histological features of the spermoviduct in the ovoviviparous Ruthenica filograna are described for the first time. The spermoviduct is composed of three grooves that are not fully separated: the oviductal channel, autospermiduct, and allospermiduct. The wall of each groove is composed of specific subepithelial glandular cells and non-secretory epithelial cells. The prostatic gland is well developed in the proximal part of the spermoviduct and connected to the autospermiduct. In the distal part, the autospermiduct diverges, forming a free vas deferens, while the rest of the spermoviduct becomes a free oviduct. Initially, the free oviduct still contains the allospermiduct and the oviductal channel. Along the spermoviduct is a small diverticulum, that in the proximal section adheres to the allospermiduct, remaining an independent duct, opening into the bursa copulatrix stalk. The reproductive system of R. filograna is similar to those of semitriaulic Stylommatophora, but the allospermiduct, unlike in Helix species, continues in the distal part of the spermoviduct and in the proximal part of the free oviduct.     

Development of the genital ducts and spermathecae in the Rhyacodrilines rhyacodrilus coccineus and Monopylephorus rubroniveus (Oligochaeta, tubificidae).

The male genital duct in Tubificidae consists of a funnel, a vas deferens, an atrium, and, frequently, a copulatory structure. There may also be a diffuse or compact prostate gland in association with the duct. The morphogenesis of this duct is described for Rhyacodrilus coccineus and Monopylephorus rubroniveus (Rhyacodrilinae). The funnel and vas deferens in both species originate from peritoneal (mesodermal) cells in the posterior septum in the testis segment. The atrium in R. coccineus develops from a primary epidermal (ectodermal) invagination. A typical atrium is not formed in M. rubroniveus; the entire duct is of mesodermal origin. In the latter species, a shallow epidermal invagination occurs, into which both male ducts open, but it bears resemblance to a copulatory structure, which usually forms from a secondary invagination, rather than to a proper atrium. We therefore conclude that M. rubroniveus lacks an atrium. The copulatory structure is termed the male bursa. Both species have diffuse prostate glands that differentiate from peritoneal (mesodermal) cells surrounding the male duct. In R. coccineus the cells cover the atrium, whereas in M. rubroniveus they cover only a part of the vas deferens. The development of the spermathecae and female ducts is also examined. The spermatheca is of ectodermal origin in both studied species, i.e., it forms as an invagination of the epidermis. The female duct develops from peritoneal (mesodermal) cells in the posterior septum of the ovary segment. However, in M. rubroniveus the first sign of the duct disappears and a proper duct never develops.     

长足大竹象生殖系统的形态解剖研究

解剖研究了长足大竹象雌雄虫牛殖系统的构造.该虫的雌性生殖系统包括一对卵巢、一对侧输卵管、中输卵管、交配囊、受精囊、生殖腔、产卵器;雄性生殖系统由一对睾九、一对输精管、一对附腺、射精管和交配器组成.     

Ultrastructural Morphology of the Male and Female Genital Tracts of <Emphasis Type="Italic">Psoroptes</Emphasis> spp. (Acari: Astigmata: Psoroptidae)

The structure of the male and female genital systems of the astigmatid mite Psoroptes ovis (Hering) is described. The male genital system is composed of a paired testis, fused at its proximal part, two vasa deferentia, an ejaculatory duct, into which a single accessory gland opens, and a copulatory organ. The testis is characterized by a peripheric syncytial cell surrounding spermatogonia, spermatocytes, spermatids and spermatozoa which are distributed regularly in the gonad according to the sequence of spermatogenesis. The female genital system consists of a copulatory pore (the bursa copulatrix), a seminal receptacle, paired ovaries and oviducts, a glandular uterus and an ovipositor which leads to the oviporus. Ovaries are composed of somatic cells, germ cells and a central cell, with a multilobular nucleus, connected to oocytes by a stalk. Similarities with other astigmatic mites belonging to Psoroptidia and Acaridia are also discussed.     

粉尘螨生殖系统形态学研究

粉尘螨Dermatophagoides farinae是一种重要的医学螨类。本文用光镜和扫描电镜研究了粉尘螨雌雄生殖系统的形态和结构。结果表明：雄性生殖系统由睾丸、输精管、 附腺、射精管、阳茎及附属交配器官组成。睾丸位于血腔末端,不成对,精原细胞、精母细胞和精子依照精子发育的顺序有规则地分布在其内部。雌性生殖系统包括交配孔、囊导管、储精囊、囊导管、卵巢、输卵管、子宫、产卵管及产卵孔,其中卵巢由一个中央营养细胞和围绕其周围的卵母细胞组成。     

Copulatory process in Oxychilus (Drouetia) atlanticus (Morelet and Drouët, 1857) (Pulmonata: Zonitidae)

Summary

Oxychilurr (Drouetia) atlanticus (Pulmonata: Zonitidae) is an endemic hermaphroditic species from São Miguel island (Azores). The copulatory process is a mutually simultaneous event and takes about 24 h from the beginning of penetration until the disconnection of the partners. Copulation is characterized by the progressive and complete evertion of the penis and penial caecum. The latter, everting completely inside the bursa copulatrix, is fundamental to the release of the anterior portion of the spermatophore, which is the first to be transferred. The anterior portion of the spermatophore is hook-shaped, aiding its anchorage to the bursa, and the posterior portion ends in a hood with an aperture through which the spermatozoa are released.     

Functional morphology of the copulatory organs of a reed beetle and a shining leaf beetle (Coleoptera: Chrysomelidae: Donaciinae,Criocerinae) using X-ray micro-computed tomography

For more than 100 years it has been known that the sclerotised median lobe of beetles harbours a membranous structure (the "internal sac" or "endophallus") which is everted during copula inside the female genital tract. In order to explore the functional role of this structure and those associated with it, we cryofixed copulating pairs of Donacia semicuprea and Lilioceris lilii and studied the relative position of the elements of the copulatory apparatus of males and females by micro-computer-tomography.We found that the everted endophallus fills the lumen of the bursa copulatrix completely. Our data suggest that in Lilioceris lilii the tip of the sclerotised distal part of the ejaculatory duct, the flagellum, is positioned exactly over the opening of the spermathecal duct inside the bursa copulatrix. The mouth of the bursa copulatrix in Donacia semicuprea is armed with a strong muscle ring, and the whole wall of the bursa is covered externally with a layer of muscle fibres. These morphological differences correspond with differences in mating behaviour: In reed beetles (Donaciinae), females seemingly can control mating to a higher degree than in lily beetles (Lilioceris spp.).     

REPRODUCTIVE SYSTEM AND SPERMATOGENESIS IN THE OPISTHOBRANCH GASTROPOD RETUSA OBTUSA (MONTAGU)

The cephalaspidean opisthobranch Retusa obtusa has an ovotestissimultaneously producing eggs and spermatozoa. Reproductiveorgans are characterized by the hermaphrodite duct and seminalreceptacle together joining the pallial glandular duct whichis differentiated anteriorly to form the ‘albumen’gland, membrane or capsule gland, and mucus gland. The ductof a copulatory bursa joins the common central chamber of thiscomplex. Eggs presumably pass through extended tracts in the3 glands to emerge at a hermaphrodite aperture in the rightside of the mantle cavity. Spermatozoa also emerge at this apertureto a ciliated seminal groove along the right side of the headwhich, in turn, joins copulatory organs folded within the headand opening close behind the right cephalic tentacle: a muscularpenial sac receives 4 elements of prostate gland. Spermatophoreswere never seen. Oocytes, surrounded by several thin folliclecells, reach 150–330 µ, m diameter in larger wintersnails, mostly in the periphery of theovotestis. Spermatocytesand spermatids develop as clusters in association with accessory(Sertoli) cells. The acrosome appears in the centre of a denseanterior plaque, develops as a domed acrosome vesicle on a shortpeduncle and eventually becomes a terminal spike on the nucleustip. The Golgi complex is seen sometimes near the early acrosomebut more often behind the nucleus. Mitochondria aggregate firstahead of the nucleus but then form a mitochondrial derivative,with a glycogen helix, spiralled around the axoneme throughoutthe mid-piece of the tail. This region is marked off from theend-piece of the tail by the annulus. The nucleus becomes long,spiralled with a strong keel, and surrounds the centriolar derivativeat the base of the axoneme.     

Two New Kalyptorhynchia (Turbellaria) from the Coast of Northern New England,USA1

Cystiplana rubra sp.n. and Crassicollum musculare gen. et sp.n. are described and their taxonomy discussed. C. rubra (family Cystiplanidae Karling, 1964) is distinguished by red pigmented stripes, two pairs of cuticular pieces within the copulatory bulb, a small male atrium posterior to the copulatory bulb, and a two part atrial bulb. C. musculare is characterized by a large, unpaired prostatic vesicle with two distinct regions of secretory products, a muscular penis papilla with a small apical stylet, large muscle bolsters bracketing a glandular evagination of the genital atrium, and a large sphincter encircling the genital canal. A new family of Eukalyptorhynchia, Crassicollidae, is erected. Notes on some biological aspects of these species are included.     

Heterochrony and growth rate variation mediate the development of divergent genital morphologies in closely related Ohomopterus ground beetles

The rapid divergence of genital morphology is well studied in the context of sexual selection and speciation; however, little is known about the developmental mechanisms underlying divergence in genitalia. Ground beetles in the subgenus Ohomopterus genus Carabus have species‐specific genitalia that show coevolutionary divergence between the sexes. In this study, using X‐ray microcomputed tomography, we examined the morphogenesis of male and female genitalia in two closely related Ohomopterus species with divergent genital morphologies. The morphogenetic processes generating the male and female genitalia at the pupal stage were qualitatively similar in the two species. The male aedeagus and internal sac and female bursa copulatrix were partially formed at pupation and developed gradually thereafter. The species‐specific genital parts, male copulatory piece, and female vaginal appendix differed in the timing and rate of development. The relatively long copulatory piece of Carabus maiyasanus began to develop earlier, but subsequent rates of growth were similar in the two species. The timing of the formation of the vaginal appendix and initial growth rates were similar, but subsequent rapid growth led to a longer vaginal appendix in C. maiyasanus. Thus, substantial interspecific differences in the size of genital parts were mediated by different underlying developmental mechanisms between the sexes (i.e., a shift in the developmental schedule in males and a change in growth rate in females). These results revealed the spatio–temporal dynamics of species‐specific genital structure development, providing a novel platform for evo–devo studies of the diversification of genital morphologies.     

中国四川北部一沟颈螺新种(柄眼目,艾纳螺总科)描述(英文)

描述了栖息于甘肃南部的陆生贝类艾纳螺科1新种,南坪沟颈螺Holcauchen nanping sp. nov.。与各已知种相比,南坪沟颈螺的次体螺层最膨大;腭壁板齿及腔壁齿阙如;具1枚强壮轴唇齿;在生殖系统中,鞭状器小,乳突状;成荚器无盲囊;纳精囊管分支盲管缺乏。南坪沟颈螺,新种Holcauchen nanping sp. nov. (图1～4)鉴别特征次体螺层最膨大;无腭壁板齿与腔壁齿;轴唇齿1枚,强壮。鞭状器小乳突状;成荚器无盲囊;纳精囊管分支盲管缺乏。正模,HBUMM06584-specimen 1,具软体部的成体,四川省九寨沟县风成寺,2011-08-14,吴岷、徐沁、Prem B.Buhda采。模式标本保存于河北大学博物馆。词源:新种种名源自九寨沟县旧称"南坪"。     

Funktionsmorphologische Untersuchungen am männlichen Kopulationsapparat von Pelodera strongyloides (Schneider, 1866) (Nematoda,Rhabditidae)

Zusammenfassung Es wird die Feinstruktur des männlichen Kopulationsapparates bei Pelodera strongyloides beschrieben. Dieser besteht aus dem Spiculum, der Spiculumtasche und der Bursa copulatrix. Der gesamte Kopulationsapparat besitzt Papillen mit sensorischen Funktionen. Dabei handelt es sich bei den Papillen der Bursa um Chemorezeptoren, während die Papillen der Spiculumtasche und des Spiculums Mechanorezeptoren sein dürften. Ein Zusammenwirken aller Strukturen bei der Kopulation wird diskutiert.

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Structure and function of the male copulatory apparatus of Pelodera strongyloides schneider 1866 (Nematoda, Rhabditidae)

Summary The male copulatory apparatus of Pelodera strongyloides is described using electron microscopical pictures. The genital structures are composed of a spicule, a spicule sac and a bursa copulatrix. Papillae of the bursa copulatrix, which are chemoreceptors, and papillae of the spicule sac and the spicule, which are mechanoreceptors, represent the sensory equipment. The co-operation of all structures during copulation is discussed.

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Mit freundlicher Unterstützung der DFG (Se 162/11).     

斑衣蜡蝉雌性生殖系统超微结构

【目的】明确斑衣蜡蝉Lycorma delicatula雌成虫生殖系统整体形态及超微结构特征,为蜡蝉总科昆虫分类及系统发育探讨提供更多形态学证据。【方法】采用光学显微镜与透射电子显微镜,观察斑衣蜡蝉雌成虫生殖系统整体形态和各主要器官的超微结构。【结果】斑衣蜡蝉雌成虫生殖系统主要包括1对卵巢、1个中输卵管、1个交配囊、1个交配囊管、1个前阴道、1个后阴道、1个受精囊、1个受精管和2根受精囊附腺。卵巢为端滋式,由14根卵巢小管组成,卵室由固有膜、滤泡细胞和卵细胞组成,卵巢小管中的滋养细胞清晰可见;中输卵管位于前阴道基部,由中输卵管腔、上皮细胞、肌肉鞘和基膜组成;交配囊膨大呈圆球状,囊壁由上皮细胞、肌肉层和基膜组成;交配囊管呈圆柱状,连接交配囊和后阴道,由肌肉鞘、上皮细胞层和管腔组成;前、后阴道超微结构相似,主要由肌肉鞘、基膜、上皮细胞和管腔组成,但后阴道上皮细胞细胞核周围存在分泌颗粒,且管腔内有大量微绒毛,而前阴道壁内包含有大量囊泡结构;受精管从中输卵管末端延伸至受精囊,由基膜、厚层肌肉鞘和管腔组成;受精囊为受精管近末端略膨大的囊状结构,由肌肉鞘、基膜、上皮细胞和囊腔构成;雌性受精囊附腺着生于受精囊末端,为均匀的螺旋管状,主要由肌肉层、上皮细胞层和附腺中心管腔组成。【结论】斑衣蜡蝉雌性生殖系统与已报道的蜡蝉总科其他类群的雌性生殖系统结构相似,但卵巢小管数目有差异;蝉亚目中不同总科雌成虫雌性附腺与受精囊附腺的形态特征存在明显区别;斑衣蜡蝉雌性生殖系统超微结构与叶蝉总科和沫蝉总科昆虫也存在部分差异。这些差异是否可以作为头喙亚目高级阶元的划分依据仍有待于进一步研究。     

The spermatozoon of arthropoda. XXIV. Sperm metamorphosis in the diplopod Polyxenus

Specimens, representative of each of the major taxa of mosquitoes, were fixed in copula and the external genitalia examined by scanning electron microscopy. The periphery of the basin-like everted aedeagus of Aedus aegypti precisely matches that of the everted atrial membrane of the female. These structures are appressed during coitus and sealed by pressure of the paraprocts, aedeagal pouch and proctiger. When everted, the aedeagus of male Culex pipiens reveals a ridged dome that surrounds the genital opening. This dome seals itself laterally into a gutter formed by pad-like extensions of the female's genital lips and is sealed dorsally by pressure of the aedeagal apodeme. The aedeagus of another culicine species, Wyeomyia smithii, bears the gonopore at the apex of a spined tube. This tube is inserted between the female's genital lips and is sealed within the genital atrium. The aedeagus of the toxorhynchitine species Toxorhynchitis brevipalpus is immobile and is inserted deep within the genital atrium of the female where it is sealed by pressure of the atrial walls. Males of each of these mosquitoes deliver a mixture of semen and sperm to the copulatory bursa of the female. After withdrawal of the aedeagus, sperm is transferred to the spermathecae. In contrast, sperm of Anopheles quadrimaculatus are delivered directly to the spermathecal duct. The tube-like aedeagus is positioned by its leaflets during sperm transfer and is driven deep into the atrium, where a mixture of semen and sperm is ejaculated. The significance of mechanical barriers to mating between species is discussed.     

Development of the reproductive apparatus of the land planarian Rhynchodemus sylvaticus (Turbellaria: Tricladida) and its significance for classification in the genus

Seven specimens of Rhynchodemus sylvaticus (Leidy) collected from a variety of localities in the US and having variously developed copulatory organs are believed to represent stages in the development of the copulatory apparatus. Four specimens were juveniles with under-developed male components, one specimen had a well-developed female atrium and small male component, and two specimens were mature with a male organ twice the size of the female part. In early stages, the male component had sperm ducts, seminal vesicle, and narrow atrium; more mature stages had a considerable elongated atrium with thick folds in its muscularized wall, a massive muscular bulbus; and a sigmoid ejaculatory duct opening into the large bulbar cavity. Morphological features of mature male copulatory organs in all species of the genus Rhynchodemus are basically similar whereas external body features (color and number of dorsal stripes) of these same species differ.     

Mating behavior and genitalic counterparts in tiger beetles (Carabidae: Cicindelinae)

Comparative studies on the structure of genitalia in Pseudoxychila tarsalis Bates and the copulating behavior in 5 species of Cicindela respectively complement similar findings by Freitag [1] on Cicindela spp. and Palmer [4] on P. tarsalis. These strengthen the hypothesis that in tiger beetles the flagellum fits into the spermatheca duct during copulation; that the main function of the flagellum, which is closed at the apex and not connected to the ejaculatory duct, is to open and prepare the lumen of the spermatheca duct for sperm movement from the bursa copulatrix to the spermatheca; and that copulation proceeds in 3 phases: phase 1 in which the lumen of the spermatheca duct is cleared by the flagellum, phase 2 in which the flagellum is withdrawn from the spermatheca duct, and phase 3 in which semen is transferred from the gonopore of the ejaculatory duct to the bursa copulatrix, usually with a spermatophore.     

Development of the genital ducts in Telmatodrilinae (Tubificidae, Clitellata)

In Tubificidae, the male genital duct comprises a funnel in the testes segment, followed by a vas deferens, an atrium, and, frequently, a copulatory structure in the adjacent ovarian segment. There may also be a diffuse or compact prostate gland in association with the duct. The morphology and position of the genital ducts are important for the classification of the oligochaetous Clitellata. Different parts of the male duct, however, have been named without regard to whether they are homologous or not. One way to establish better hypotheses of homology is to study the detailed morphology and/or the development of the genital ducts. The morphogenesis of the genital ducts in Alexandrovia onegensis (Telmatodrilinae) is described. The male funnel originates by multiplication of peritoneal (mesodermal) cells in the posterior septum in the testes segment. A cord of these cells breaks through the septum and grows backwards into the next segment, where it connects to the epidermis. This cord gives rise to the vas deferens, and is therefore mesodermal in origin. The atrium in A. onegensis develops from a primary epidermal (ectodermal) invagination. The vas deferens and atrium connect and a continuous duct from the testes segment to the exterior is formed. Several compact prostate glands develop along the atrium, each being formed from cells in the atrial epithelium. The spermatheca develops from an invagination of the epidermis in the testes segment. The female duct is formed from peritoneal (mesodermal) cells in the posterior septum in the ovarian segment. These developmental findings strengthen the hypothesis about a closer relationship between the Telmatodrilinae and Tubificinae (both Tubificidae).     

Specific criteria in Grania (Oligochaeta,Enchytraeidae)

The structure of the penial bulb and male efferent duct system of Grania species may be used in addition to setal pattern and spermathecal shape to distinguish species. Six penial bulb types are distinguished: (1) a simple, small, glandular bulb surrounding the male pore; (2) a small, glandular bulb, with a large, associated, dorso-medial gland mass; (3) a small glandular bulb, medial to the male pore, with an elongate male bursa (the aglandular sac), the vas deferens exitting directly into the invaginated male pore; (4) a glandular bulb with an aglandular sac and a small, cuticular stylet embedded in the bulb, extending from the ectal end of the vas deferens; (5) a glandular bulb and an aglandular sac with a long stylet extending from the vas deferens, through the bulb into the sac; and (6) glandular bulb reduced or absent, with or without an aglandular sac; with a long stylet and other prominent modifications, usually muscular, of the vas deferens. The details of the male duct structure were consistent within specimens grouped on the basis of setal distribution and shape and detailed spermathecal structure. Diverse male duct patterns are found within the polytypic species G. macrochaeta and G. postclitellochaeta. The positions of the spermathecal and male pores in their respective segments are distinctive for some species.