Monophyly of elapid snakes (Serpentes: Elapidae). An assessment of the evidence

The defining morphological characters of the family Elapidae are analysed in an attempt to evaluate whether the front-fanged, proteroglyphous, snakes constitute a natural (monophyletic) group or whether proteroglyphy is more likely to be a condition achieved independently by a number of higher snake lineages. The evidence relating to presumed elapids whose affinities have been questioned, namely a South African genus Homoroselaps and New World proteroglyphs (Micrurus and Micruroides) , is examined. It concluded that Homoroselaps is a genuinely equivocal case, the evidence for its inclusion in the Elapidae is balanced by features which suggest that it is more closely related to the Aparallactinae. However, Micrurus and Micruroides seem clearly to be more closely related to undisputed elapids than to any other caenophidians. It is suggested that, at least for the present, the family Elapidae be retained in its broad sense to include all proteroglyphous snakes.     

Studies in the secretory glands of Hiptage sericea (Malpighiaceae)

Hiptage sericea is shown to possess both lipophilic glands and extrafloral nectaries. Both types of glands develop from a group of initials and show similarities in organisation of tissue systems and secretion. The nature of the secretory substances is however different. The occurrence and function of the glands are discussed.     

The comparative morphology of epidermal glands in Pentatomoidea (Heteroptera)

The Heteroptera show a diversity of glands associated with the epidermis. They have multiple roles including the production of noxious scents. Here, we examine the cellular arrangement and cytoskeletal components of the scent glands of pentatomoid Heteroptera in three families, Pentatomidae (stink bugs), Tessaratomidae, and Scutelleridae (shield-backed bugs or jewel bugs). The glands are; (1) the dorsal abdominal glands, (2) the tubular glands of the composite metathoracic gland, and (3) the accessory gland component of the composite metathoracic gland. The dorsal abdominal glands are at their largest in nymphs and decrease in size in adults. The metathoracic gland is an adult-specific gland unit with a reservoir and multiple types of gland cells. The accessory gland is composed of many unicellular glands concentrated in a sinuous line across the reservoir wall. The lateral tubular gland is composed of two-cell units. The dorsal abdominal glands of nymphs are composed of three-cell units with a prominent cuticular component derived from the saccule cell sitting between the duct and receiving canal. The cuticular components that channel secretion from the microvilli of the secretory cell to the exterior differ in the three gland types. The significance of the numbers of cells comprising gland units is related to the role of cells in regenerating the cuticular components of the glands at moulting in nymphs.     

Epidermal glands in Squamata: morphology and histochemistry of the pre-cloacal glands in Amphisbaena alba (Amphisbaenia)

Summary Pre-cloacal glands occur in some species of amphisbaenians. Although these glands are important in systematics, their biology and chemistry are little known. The pre-cloacal glands of Amphisbaena alba are of the holocrine type. They are made up of a glandular body and a duct. The glandular body is conical to elongate and is formed of clongatc lobules separated one from another by collagen septa. Each lobule is composed, at its periphery, of germinative cells, and within of polyhedral secretory cells, of different degrees of differentiation. The germinative cells, set on a basal lamina, are basophilic and their cytoplasm is fairly electron dense. The polyhedral cells display bulky cytoplasm, filled with spherical granules, wrapped in membranes and differing in their electron densities. Towards the lumen of the gland, these granules are increasingly eosinophilic and have an affinity for orange G. The secretion is discharged into the duct leading to the pore, which is situated in the central region of the scale. This secretion shows positive histochemical results for mucopolysaccharides and proteins. The similarity between the epidermal glands of lizards and those of A. alba raises the suggestion that the glands have equivalent functions, possibly in the course of intra- or interspecific communication.     

Ultrastructure of the sexually dimorphic tarsal glands and tegumental glands in gonyleptoid harvestmen (Opiliones,Laniatores)

In at least four closely related families of the diverse harvestmen lineage Gonyleptoidea, males may possess sexually dimorphic tarsal glands in the swollen tarsomeres of the basitarsus and/or metatarsus of leg I. The first histological and ultrastructural examination of the sexually dimorphic tarsal glands in leg I focused only on Manaosbiidae. In this study, we examine the morphology and ultrastructure of the sexually dimorphic glands, and their associated glandular openings, found in the basitarsus and/or metatarsus of leg I of males representing Cosmetidae, Gonyleptidae, and Cranaidae (glandular openings only). In cosmetids and gonyleptids, the tarsal glands are made up of 20–60 glandular units that form distinct groups within the prolateral and retrolateral half of the tarsomere. Each glandular unit consists of a pair of terminal secretory cells, an intercalary cell wrapped around the receiving canal, and a canal cell tightly wrapped around the length of the conducting canal. Cosmetidae, Gonyleptidae, and Cranaidae exhibit remarkably similar tarsal glands and gland openings although the location of the glands in the leg differs slightly among them. Males of these three families exhibit markedly different glands and glandular openings compared to males of the family Manaosbiidae. The sexually dimorphic tarsal glands may provide an important morphological character for determining phylogenetic relationships among gonyleptoid families. Finally, we provide morphological and ultrastructural data for the common tegumental glands. These data indicate that the sexually dimorphic tarsal glands are strikingly similar to, and may possibly be derived from, the tegumental glands. J. Morphol. 274:1203–1215, 2013. © 2013 Wiley Periodicals, Inc.     

Functional morphology of the mammiliform penial glands ofLittorina saxatilis (Gastropoda)

Summary The functional morphology of the mammiliform penial glands ofLittorina saxatilis has been investigated with both light and electron microscopy. These penial glands line the ventral edge of the penis and orient with the female mantle during copulation. Secretions are released from the penial glands to this interface where they probably function in adhesion. The penial gland secretions comprise heterogeneous granules as well as apocrine and mucous secretions. The heterogeneous granules are produced in separate multicellular glands arranged in a series of lobes that lie outside a thick smooth muscle layer enclosing the lumen. Each glandular lobe is surrounded by a thin layer of smooth muscle. Secretions are transported in individual cellular processes that pass through the thick smooth muscle layer and empty into the lumen. Surrounding the lumen is an epithelium containing apocrine secretory cells as well as occasional goblet-type, mucous cells. The combined action of the muscles forces secretions out of the lumen through the penial papilla, onto the external surface of the mammiliform penial gland. Longitudinal muscles extend into the penial papilla enabling its protrusion or retraction. Retraction of the penial papilla following secretion release is thought to create negative pressure beneath the penial gland producing suction adhesion. The visco-elastic properties of the penial gland secretion are qualitatively different from foot mucus and may represent specialization to an adhesive function.     

Ultrastructure of the glands producing sex pheromones of the male Nauphoeta cinerea (Insecta,Dictyoptera)

Summary The abdominal glands described here play a decisive role in the typical sexual behavior of Nauphoeta cinerea. Unlike other cockroaches, the males of this species produce two successive chemical signals: the sex pheromone itself, produced by the sternal glands, attracts the female from a distance, and the aphrodisiacs, secreted by the tergal glands, are licked by the female who is thus in a favorable position for mating. The well developed glandular apparatus is composed of 5 sternal glands (St3 to St7) and 7 tergal glands (T2 to T8). These glands appear as a thickening of the epithelium without significant modification of the external cuticle. The glandular epithelium is made up of several kinds of cells: ordinary epidermal cells (which only exist in the sternal glands), cells with microtubules, type 2 cells (oenocytes), and especially type 3 glandular units (composed of a secretory cell and a canal cell). The products secreted by the sternal glands are chiefly volatile products and fatty acids and those secreted by the tergal glands are primarily fatty acids and proteins. In this work, the relationship between the cytology of the glandular cells and the nature of the secreted products is discussed.     

Ultrastructure of the male accessory glands ofAllacma fusca(Insecta, Collembola)

The accessory glands ofAllacma fusca(L.) (Insecta, Collembola, Sminthuridae) consist of a series of secretory units that are arranged in parallel and open into the ejaculatory duct. Each unit is composed of microvillate cells stacked around a common cavity. Basal cells are involved in ion-control of fluids from the hemocoel to the cavity. The intermediate and apical cells, which have a laminar appearance and contain many microtubules, are involved in the structural integrity of the unit. Supporting cells ensheath the most apical cells. Large openings in the cuticle allow the gland secretion to flow into the ejaculatory duct lumen. These openings are protected by a porous cuticle different from that lining the epithelium of the ejaculatory duct. Conspicuous muscle fibers run along the lateroventral side of the ejaculatory duct beneath the insertion of the accessory glands. The fine structure of the accessory glands indicates that they are type I ectodermic glands as defined by Noirot & Quennedey (1974). Their function could be to control the fluidity of the material for spermatophore formation and to ensure the proper physiological conditions for spermatozoa stored in the ejaculatory duct lumen.     

Structure and development of bracteal nectary glands in Aphelandra (Acanthaceae)

A survey of bracteal (extrafloral) nectaries in species of Aphelandra (Acanthaceae) reveals substantial diversity. Each bracteal nectary is an aggregate of individual glands that vary in number, size, and structure among species. Glands contain three cell layers: a palisade-like secretory cell layer, a one-to-many-celled intermediate layer with thickened cell walls, and a foot layer. Members of the A. pulcherrima complex have one of two distinct gland types: relatively small glands with a single-celled intermediate layer or larger glands that have a multicellular intermediate layer. Nectaries composed of small glands are patches of many (>50) glands, whereas those composed of large glands are patches of < 10 glands. Four outgroup species have bracteal nectaries of numerous small glands with pluricellular intermediate layers. Glands of all three types are initiated as single enlarged protodermal cells, and all undergo similar early periclinal divisions; the large-gland type shows greater subsequent enlargement with many more anticlinal divisions. The bracteal nectar glands are interpreted to be homologous with simpler glandular trichomes, and mark a monophyletic lineage within Aphelandra. Comparisons with outgroup species show that both nectary types in the A. pulcherrima complex have diverged from an ancestral condition of numerous small glands with pluricellular intermediate layers. Use of the ontogenetic criterion to polarize gland type within the A. pulcherrima complex would yield erroneous results because evolution has apparently involved a developmental truncation with loss of cell divisions in the intermediate layer of small glands. Comparable nectar glands in more distant taxa are interpreted as remarkable cases of convergent evolution, perhaps from similar trichome precursors.     

Ultrastructural investigation of the vesicular glands in Scutigera coleoptrata (Chilopoda,Notostigmophora)

In the notostigmophoran centipedes, two pairs of vesicular glands have evolved. These paired glands are situated in the first and second trunk segment and open via cuticular ducts in the upper part of the particular pleura. The vesicular glands of Scutigera coleoptrata were investigated using light and, for the first time, electron microscopical methods. The glands consist of wide sac‐like cavities that often appear vesicular. The epithelia of both glands are identically structured and consist of numerous glandular units. Each of these units consists of four different cells: a single secretory cell, a small intermediary cell, and one proximal and one distal canal cell. The intermediary cell forms a conducting canal and connects the secretory cell with the canal cells. Proximally, the intermediary cell bears microvilli, whereas the distal part is covered with a distinct cuticle. The cuticle is a continuation of the cuticle of the canal cells. This investigation shows that the ultrastructure of glandular units of the vesicular glands is comparable to that of the glandular units of other epidermal glands in Chilopoda and Diplopoda, although the glands look completely different in the light microscope. Thus, it is likely that the vesicular glands and epidermal glands share the same ground pattern. With regard to specific differences in the cuticular lining of the intermediary cells, a common origin of epidermal glands in Myriapoda and Hexapoda is not supported. J. Morphol. 2009. © 2008 Wiley‐Liss, Inc.     

斑透翅蝉唾液腺细菌群落组成研究

【目的】为明晰蝉类昆虫唾液腺中细菌的组成及其中是否存在内共生菌Candidatus Sulcia muelleri。【方法】以斑透翅蝉Hyalessa maculaticollis (Motschulsky)为材料,采用16S rRNA限制性内切酶片段长度多态性(RFLP)对其唾液腺细菌群落组成进行分析。【结果】斑透翅蝉唾液腺中共存在7种细菌,分别属于变形菌门和厚壁菌门;其中绿脓假单胞杆菌Pseudomonas aeruginosa和肠杆菌Enterobacter sp.为优势细菌,分别占克隆总数的48.7%;另外5种细菌(反硝化细菌热单胞菌Thermomonas brevis、鞘胺醇单胞菌Sphingomonas sp.、芽孢杆菌Bacillus sp.、厌氧球菌Anaerococcus sp.和Methyloversatilis sp.)总共占克隆文库的2.05%。【结论】首次采用分子生物学方法明晰斑透翅蝉唾液腺的细菌群落;其细菌群落组成相对简单,且两种细菌占主导地位;此外,头喙亚目昆虫体内特有的内共生菌Candidatus Sulcia muelleri未在斑透翅蝉唾液腺中检测出,表明该共细菌可能仅在腹部的贮菌体中分布;斑透翅蝉唾液腺中的细菌是否普遍存在于蝉科昆虫唾液腺中以及在取食韧皮部汁液过程中的功能有待进一步研究。     

The evolution of food-producing glands in eusocial bees (Apoidea,Hymenoptera)1

A food-producing role for cephalic exocrine glands has arisen independently in both taxa of highly eusocial bees, Apis and Meliponini. With several exceptions, there is little evidence that food is produced by glands of solitary bees or by most bees at lower levels of sociality. We suggest that this association with sociality is due to four adaptive features of these glands: (1) food from the glands allows feces from queens and larvae to have a small volume, (2) the queen's fecundity can be increased, (3) nutrient recovery via cannibalism can be facilitated, and (4) rearing of emergency replacement queens is accelerated. Acceleration of the rearing of other castes and of queens in the normal process of colony fission is not clearly an advantage ascribed to these glands. Trophic eggs produced by meliponine colony workers are analogous to the secretions from food-producing glands in Meliponini and Apis workers.     

Foregut glands of Solenogastres (mollusca): anatomy and revised terminology

In the molluscan class Solenogastres, different types of foregut glands vary in number, structure, and location within the foregut. The present article describes their anatomy and cytology and intends to clarify their confused terminology. Pharyngeal glands, esophageal glands, and the more complex dorsal and ventrolateral foregut glands can be distinguished. The ventrolateral foregut glands (ventral foregut glandular organs, ventral salivary glands of auct.), in the literature subdivided previously into four types, are revisited here in the context of current vertebrate gland terminology. The results of recent investigations are added to earlier ones, and a classification system for these multicellular glands is proposed. This system is based on cytological characters of glandular cells (intra- or extraepithelial), characters of the associated musculature (inner or outer musculature), location of the gland relative to the pharynx epithelium (endoepithelial or exoepithelial), characters of the gland openings (paired or unpaired), morphology of the gland duct (simple or branched), and some additional features like the arrangement of glandular cells along the gland ducts. Gross morphology and anatomy of ventrolateral foregut glands constitute useful taxonomic characters in determining higher taxa (family level), and finer details of the anatomy and cytology are useful in determining lower levels (genus and species). Possible pathways for the evolution of the different gland types of Solenogastres in relation to foregut glands present in the other molluscan clades are presented. The importance of ventrolateral foregut gland characters for phylogenetic considerations within the Solenogastres is discussed.     

The salivary glands of the cockroach Nauphoeta cinerea (Olivier)

The innervation of the salivary gland of the cockroach Nauphoeta cinerea (Olivier) has been investigated with the use of light and scanning electron microscopy. Light microscopy of methylene blue stained glands reveals the presence of a dual innervation arising from the ventral nerve cord and the stomodeal nervous system; the principal innervation is that from the ventral nerve cord which passes to the gland via the reservoir ducts. Branches of these nerves form a plexus on the acinar surface, the axons of which exhibit swelling at irregular intervals. The presence of this surface plexus and the axonal swellings was confirmed by scanning electron microscopy both in normal glands and in those in which the basal lamina had been removed by means of an HCl-collagenase digestion method. No acinar plexus was seen to be formed by branches of the stomatogastric nerve that were associated with the gland. However, other branches of this nerve were clearly connected with a complex network of multipolar neurones on the surfaces of the anterior regions of both salivary reservoirs.     

Vasculature of the parotoid glands of four species of toads (bufonidae: bufo)

The parotoid glands of toads (Bufonidae) consist of large aggregations of granular glands located between the otic region of the skull and the scapular region. To determine the circulatory pattern of these glands, we perfused the vascular systems of Bufo alvarius, B. marinus, B. terrestris, and B. valliceps with either India ink or Microfil, a fine latex. The perfused glands were studied by gross dissection, microscopic examination, and histology. The vascular patterns of the parotoid glands were compared to the arrangement of vessels in the dorsal skin of Rana sphenocephala (Ranidae), a frog that lacks parotoid glands. The parotoid glands of the four species of toads are supplied with blood by the lateral and dorsal cutaneous arteries and are drained by one or more branches of the internal jugular vein. The dorsal cutaneous artery supplies most of the blood to the parotoid glands in B. terrestris and B. valliceps. In B. alvarius and B. marinus, both the lateral and dorsal cutaneous arteries serve major roles in the blood supply of the glands. These patterns of blood flow have not been described previously for parotoid glands and conflict with earlier accounts for B. alvarius and B. marinus. The arteries and veins associated with the parotoid glands of toads are present in R. sphenocephala, but are arranged differently. In R. sphenocephala, the lateral cutaneous artery supplies the dorsal and lateral skin posterior to the shoulder region, whereas the dorsal cutaneous artery supplies the skin of the shoulder region. In toads, both the lateral and dorsal cutaneous arteries supply the skin of the shoulder region and ramify into subcutaneous capillaries that surround the secretory units of the parotoid glands. Extensive vasculature presumably is important for delivering cholesterol and other precursor molecules to the parotoid glands, where those compounds are converted into toxins.     

Seasonal changes in the skin glands of Roe deer (Capreolus capreolus)

Seasonal changes in the specialized skin glands of the forehead, metatarsal gland and interdigital regions of Roebucks are described and compared with glands of the general body surface. In both the forehead region and dorsal skin the sebaceous and apocrine glands enlarge as the testes enlarge and regress after the rut, but the glands of the forehead region are at least three times larger than those of the general body surface. The apocrine glands of the forehead region discharge by exocytosis except at the time of maximum secretion, which precedes total cell breakdown. In the metatarsal and interdigital regions the skin glands are enlarged throughout the year.     

The exocrine glands of Dysdercus cingulatus (Heteroptera,Pyrrhocoridae): Morphology and function of nymphal glands

The exocrine glandular system of the nymphs and the adults of Dysdercus cingulatus were studied. The D. cingulatus nymphs present 3 dorso-abdominal glands (lying under the 3rd, 4th, and 5th abdominal terga) and a pair of dorso-lateral pygidial glands on the pygidium (tergum 8). Histological and ultrastructural studies show that the upper and lower walls of the dorso-abdominal glands differ in structure; 3 types of cells were described: epidermal cells, unicellular secretory cells, and multicellular secretory units. Each of these exocrine glands plays an important part in the behavior of the nymphs (gregariousness, alarm, defense). The morphology of the various glands is discussed, and the chemistry of their secretions and their biological functions are considered.     

Adhesive glands in the Pterastericolidae (Plathelminthes,Rhabdocoela)

Summary The ultrastructure of anteroventral gland cells with processes penetrating the epidermis inPterastericola bergensis, P. fedotovi, P. pellucida and the undescribedP. (sp. Rottnest) was studied with transmission and scanning electron microscopy. Specimens ofP. pellucida were shock frozen in situ in the epithelium of their asteroid host to study the function of the glands. Secretory products released from the gland cell processes fan out towards the host epithelium. The glands are concluded to have an adhesive function. They are compared with similar structures in Neodermata and other rhabdocoel taxa. The phylogenetic significance of the glands is discussed.Abbreviations b basal lamina - c cilium - cr ciliary rootlets - d septate desmosome - g gland cell process - gc gland cell - h host epithelium - m mitochondria - mc muscle cell - mv microvilli - mt microtubules - n nucleus - o ootype - pm plasma membrane - s secretory granule - sm secretory material released from dissolving secretory granules     

Localization and fine structure of the female sex pheromone-producing glands in Bruchidius atrolineatus (PIC) (Coleoptera : Bruchidae)

The sex pheromone glands of female Bruchidius atrolineatus (Coleoptera: Bruchidae) have been localized by recording the electric response of the antenna of males subjected to a stream of air, containing the volatile sex pheromone (electroanntennography-EAG). Some 50 unicellular glands are distributed irregularly in the ventral and dorsal intersegmental membranes situated at the extremity of the pygidium, each gland containing a short ductule with an evacuation pore, 0.5–1 μm in diameter. The receiving canal is composed of a network of fine epicuticular filaments. The glands are type 3. The ultrastructure of these sex pheromone-producing glands is described in females whose production-emission activity had been previously verified with EAG. Deep basal invaginations and inflated intercellular spaces indicate the transport of substances from the hemolymph to the gland cells. The presence of numerous elongated mitochondria, diverse inclusions, vesicles containing crystalline bodies, and abundant apical microvilli, all reveal elevated cellular activity, which is never observed in young or diapausing females that do not produce sex pheromone. The ultrastructural differences in different types of females (sexually active or diapausing), combined with comparative EAG recordings obtained with intact females or those in which the suspected glandular zone was masked, made it possible to localize the glands.     

Location and ultrastructure of sex pheromone glands in female Callosobruchus maculatus (Fabricius) (Coleoptera : Bruchidae)

The ultrastructure of the female sex pheromone glands in Callosobruchus maculatus (Coleoptera : Bruchidae) were localized using a masking technique, combined with eiectro-antennography and by a comparison of the glandular cells of sexually active (flightless) females and non-sexually active (flight-form) females. Each unicellular gland is an invagination of the integumental membrane capped by a single secretory cell. These glands are situated on the fine intersegmental membrane, which joins the pygidium to the ovipositor. The secretory cells of the glands of active females are characterized by well-developed microvilli, with many elongated mitochondria among the latter. The high metabolic activity of these cells is revealed by the presence of heterogeneous secretion vesicles, some of which contain abundant crystallized material. Deep basal invaginations indicate the uptake of substances from the haemolymph. The receptor canal is a network of fine cuticular filaments which have the same structure regardless of the female's sexual status. Cells from the glands of non-sexually active females are underdeveloped and show no invaginations of the basal membrane and very few microvilli. The localization of these glands was made possible by the use of SEM, TEM and EAG as well as by masking the suspected zones and by comparing females in different physiological states: flightless females, which were sexually active and producing pheromones; and flight-form females, non-sexually active and producing no sex pheromones. Only by adopting such a stringent method was it possible to confirm the function of the glands whose ultrastructure was studied.