Cuticular ultrastructure of Chordodes nobilii Camerano, 1901, with a comparison of cuticular ultrastructure in horsehair worms (Nematomorpha)

The cuticle of Chordodes nobilii Camerano, 1901 is composed of a proximal layer with about 30 sheets of large fibers in alternating orientations and a distal layer, which mainly forms the surface structures, the areoles. The three different types of areoles, simple, tubercle and crowned areoles, are formed mainly by material of strong and medium electron density. The tubercle areoles have a basal constriction and paired spherical structures of unknown function below the base. Irregularly distributed are paired, cushion-like structures, from which projections traverse the cuticle and run into the epidermis. In the crowned areoles, these cushions also send projections into the apical filaments. A comparison with the few ultrastructurally described cuticles from other species reveals some similarities between the cuticles of C. nobilii and Paragordius varius, making it probable that the cushion-like structures are homologous. However, Pseudochordodes bedriagae, which is more closely related to Chordodes than Paragordius, lacks the cushions. Problematic is the interpretation of different cuticular structures in Gordius. If correctly determined, areoles are present in some Gordius species and resemble in their structure areoles from other species. If areoles have to be regarded as homologous, the absence of a distal layer and areoles would have to be interpreted as a secondary reduction in species such as Gordius aquaticus.     

Variation of cuticular characters in the Nematomorpha: studies on Gordionus violaceus (Baird, 1853) and G. wolterstorffii (Camerano, 1888) from Britain and Ireland

Gordionus violaceus (Baird, 1853) and G. wolterstorffii (Camerano, 1888) are regarded as two species which are clearly separated by distinct cuticular patterns. A study of 59 specimens of these two species from Britain and Ireland revealed numerous transitional stages between the cuticular patterns that are regarded as being typical for each species. Variation was also found at the posterior end, but no character separates both species. Therefore, G. violaceus and G. wolterstorffii might represent one polymorphic species. Four specimens resembled G. violaceus but had a different cuticular pattern, including a second type of areole occurring in a pattern which has been named a megareolar pattern. This might represent a separate species, but a detailed determination relies upon further revisional work in the genera Gordionus, Parachordodes and Paragordionus.     

Description of Gordionus porosus n. sP. and redescription of Gordionus ondulatus (Nematomorpha, parachordodinae) with scanning electron microscopy

Two hairworms from Argentina, Gordionus porosus n. sp. and Gordionus ondulatus (Nematomorpha, Gordioidea), are described and illustrated. The cuticle of both species shows only 1 areolar type. Areoles of G. porosus are polygonal and surrounded by minute bristles and the interareolar groove is wide and with large pores. Gordionus ondulatus is characterized by rectangular or irregular areoles from which margins cuticular elongations project as finger-like structures, giving an undulated appearance. Comparing these species to the remaining American species of Gordionus, G. porosus is close to Gordionus violaceus by virtue of the large number of small bristles surrounding the areoles and can be distinguished by the shape of these bristles and by the arrangement and shape of the areoles. Gordionus ondulatus differs from the other species of the genus by its undulating margins. Giordinus lineatus and Giordinus violaceus have been reported in North America, Giordinus platycephalus in North and Central America, Giordinus capitosulcatus in Central America, and Giordinus prismaticus, G. ondulatus, and G. porosus only in South America.     

Ultrastructure of the body wall of three species of Grania (Annelida: Clitellata: Enchytraeidae)

De Wit P., Erséus C. and Gustavsson L.M. 2011. Ultrastructure of the body wall of three species of Grania (Annelida: Clitellata: Enchytraeidae). —Acta Zoologica (Stockholm) 92 : 1–11. The body wall of three species of Grania, including the cuticle, epidermis and the musculature, are studied using TEM. The cuticle is similar to previously studied enchytraeids, with an orthogonal grid pattern of collagen fibers. This pattern is also seen in Crassiclitellata, which has been suggested as the sister taxon of Enchytraeidae. Variation of epicuticular and fiber zone patterns seen in Naididae (formerly Tubificidae and Naididae) seem to be lacking in Enchytraeidae. The fiber thickness, however, varies between Grania species and may be a phylogenetically informative character. The epidermis consists of supporting cells, secretory cells and sensory cells. Basal cells, typical for Crassiclitellata, were not observed. The clitellum of Grania seems to consist of two types of gland cells, which develop from regular epidermal tissue. It is possible that more cell types exist in different regions of the clitellum, however. The body wall musculature is arranged somewhat differently from that of closely related taxa; this refers to the reduction of circular and outer, triangular longitudinal muscle fibers, while the inner, ribbon‐shaped longitudinal muscle fibers are well‐developed. A search was conducted for the cause of the peculiar green coloration of Grania galbina De Wit and Erséus 2007, and it was concluded that neither cyanobacteria nor epidermal pigment granules were present in the fixed material.     

Scanning electron microscopy of Spinochordodes tellinii (Camerano, 1888), (Gordiacea, Nematomorpha)

There are many species of Nematomorpha which are deficiently described and therefore pose doubts about their actual taxonomic position. This is the case with Spinochordodes tellinii (Comerano, 1888), which was transferred to four different genera and has been recently considered as species incertae sedis. A female of Spinochordodes tellinii is redescribed in this work under light microscopy and Scanning Electron Microscopy. Cuticle details, shapes and areolar distribution and the features as well as the location of spiniform structures are analysed. The systematic position is discussed.     

A REVISION OF ARIOCARPUS (CACTACEAE). I. THE STATUS OF THE PROPOSED GENUS ROSEOCACTUS

Anderson, Edward F. (Claremont Graduate School, Claremont, California.) A revision of Ariocarpus (Cactaceae). I. The status of the proposed genus Roseocactus. Amer. Jour. Bot. 47(7) : 582–589. Illus. 1960.—The proposed genus Roseocactus Berger is found to be a subgenus of Ariocarpus. The subgenera Ariocarpus and Roseocactus are basically similar in habitat, seedlings, presence of mucilage systems, tubercle structure, seed structure, fruiting habit, flower origin and structure, alkaloidal properties, trichomes, pollen grains, and chromosome number. They differ in flower color, presence or absence of an areolar groove, tubercle divergence, and trichome texture. A hypothesis is proposed to explain variations in the areoles. The differences in structure of mature tubercles are thought to be due to variability in the location of growth and elongation with respect to the floral and spinous areolar areas.     

Structure of the integument in Paranthessius anemoniae claus,a copepod associate of the snakelocks anemone Anemonia sulcata (Pennant)

The integument of Paranthessius anemoniae has been studied with light and electron microscopy. A cuticle with clearly defined epicuticular, exocuticular and endocuticular regions overlies a cellular hypodermal layer. The distribution of carbohydrate, lipid and protein components of the cuticle were demonstrated histochemically. Parabolic striations in oblique sections of cuticle suggest that its molecular architecture fits a “twisted sheet” theory proposed for other species. Arthrodial membranes at body and limb joints have a homogeneous structure, lacking exocuticle and endocuticle. Subcuticular glands appear to secrete substances thought to be responsible for the immunity which Paranthessius seems to have to the nematocysts of its host. Small hairs, situated in cuticular cups which occur over the dorsal body surface are considered to function as rheoreceptors.     

The integumental ultrastructure of Lamippe rubra Bruzelius and Enalcyonium rubicundum Olsson (Copepoda,Poecilostomatoida)

The integument of Lamippe rubra Bruzelius and of Enalcyonium rubicundum Olsson has been studied with the electron microscope.Most of the cuticle covering the body of Lamippe is represented by the epicuticle, which shows an average thickness of about 2.0 µm, but in sclerified zones it consists of a thin epicuticle (0.2 µm) and a stratified laminated procuticle (0.5–1.5 µm) without bow-shaped structure. A complex system of epithelial microvilli or a well-developed system of membranes running parallel to the cuticle is also present.The cuticle of Enalcyonium consists of a thin procuticle (0.4–0.5 µm) covered with a uniform fibrillar coat (0.5 µm), whereas in sclerotized areas it is composed of a stratified procuticle (0.7–3.5 µm) with bow-shaped structures.In both species, cuticular hairs and gland vents occur at the dorsal and ventral surfaces. Some of the hairs are considered to be sensory in nature.The cuticular ultrastructure of L. rubra and of E. rubicundum is compared with that of some other copepods.     

Variations in stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in different body parts and eggs of adult stoneflies (Plecoptera)

Variations in δ¹³C and δ¹⁵N might arise from differences in nutrient allocation. Residence times of δ¹³C and δ¹⁵N vary among tissues depending on metabolic turnover rates. However, because of their small size, entire individual insects are generally used as single samples in isotope analyses. The present study aimed to determine the degree of isotope similarity among regions of the adult body and eggs in four species of Plecoptera (Amphinemura sp., Sweltsa sp., Kamimuria tibialis Pictet and Ostrovus sp.). Levels of δ¹³C and δ¹⁵N differ between the four species, being lowest in Amphinemura sp., and with δ¹⁵N being highest in Sweltsa sp. Egg masses contain consistently the lowest values of δ¹³C in the four species, with the δ¹⁵N value of eggs being highest in K. tibialis and Ostrovus sp., and lower in Amphinemura and Sweltsa spp. In Sweltsa sp., the δ¹⁵N levels of the dermal layers and cuticle are lowest, whereas the δ¹³C values of the dermal layers and cuticle are almost equal to those in other regions of the body, except egg masses. Oviposited individuals of Amphinemura and Sweltsa spp. have lower δ¹⁵N levels than individuals that have not oviposited. The rates of metabolism and incorporation of dietary metabolites will differ depending on the body regions and species. Differences in egg ecology such as egg developmental period and egg buoyancy among species are considered to impact on the values of δ¹³C and δ¹⁵N. These results will be useful for understanding the nutritional status of aquatic insects and their energy allocation.     

Cotyledon areoles in Bobgunnia (Fabaceae: Swartzieae)

Cotyledon areoles, a seed character unique to papilionoid legumes, are reported for the first time in the legume tribe Swartzieae, an anomalous group sometimes considered to be intermediate between subfamilies Caesalpinioideae and Papilionoideae. Bobgunnia madagascariensis has a linear, slightly branched cotyledon areole on the abaxial surface of each cotyledon. Previous reports of other papilionoid seed features in this species are confirmed and extended. These highly distinctive papilionoid seed structures, and recent reports from floral ontogeny and molecular systematics which show Bobgunnia to be closely related to Swartzia and several other genera of Swartzieae, add further evidence to assertions that Swartzia seed structures are derived by simplification from a papilionoid seed, and not by retention of less specialized caesalpinioid seed features. The function and evolutionary advantage of cotyledon areoles are unknown and need investigation. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 287–291.     

Fine structure of body wall cuticle of females of Meloidodera charis,Atalodera lonicerae,and Sarisodera hydrophila (Heteroderidae)

The body wall cuticle of adult females of Meloidodera charis, Atolodera lonicerae, and Sarisodera hydrophila is examined by transmission electron and light microscopy for comparison with Heterodera schachtii and previous observations of additional species of Heterodera, Globodera, and Punctodera. The cuticle of M. charis is least complex, consisting of layers A, B, C (with A outermost), and varies in overall thickness from 3 to 8 μm. As in other species, the cuticle is thickest in mature specimens. The cuticle of A. lonicerae is 6-9 μm thick; unlike M. charis it has an innermost layer, D, in addition to A, B, and C. The cuticle of S. hydrophila varies from 14 to 30 μm thick and includes a D layer similar to A. lonicerae; layer C is subdivided into additional zones relative to other heteroderids, and the external portion of the cuticle is infused with an electron-dense material. The presence of a D layer in A. lonicerae and S. hydrophila is a character state which is shared with Globodera spp. and Punctodera sp. The electron-dense material in the outer layers of S. hydrophila also occurs in Globodera spp. and Punctodera sp. On the other hand, H. schachtii resembles other Heterodera spp. as well as M. charis by the absence of a D layer and lack of electron-dense material in the outer layers. The pattern of occurrence of shared character states, including those of the cuticle, may be useful for phylogenetic analysis of Heteroderidae.     

Ultrastructure and cytochemistry of the integument of Modiolicola gracilis,parasitic copepod in mussel gills (Mytilus galloprovincialis and Mytilus edulis)

Of mussels taken from the Ebro Delta River (E. Spain), 3% have a nonmodified copepod, Modiolicola gracilis, in the gill tissues. The cuticle of different segments of the body has an epicuticle with two layers, which show external microvilli-like projections. Weakly positive reactivity to the PTA technique has been detected in the external region. The procuticle has the helicoidal architecture of the chitinous tegument in arthropods, whereas the cuticle shows discontinuities in the regions of ducts in tegumental glands. The integument is comprised of three types of cells. Epidermal cells are flat with numerous mitochondria. Muscle cells show well-developed mitochondria with several longitudinally distributed cristae. A third and secretory cell shows a well-developed rough endoplasmic reticulum and Golgi complex in the basal zone. Its apical portion is full of secretory granules. Through the cuticle, these integumental glands open directly to the cuticular surface via a short duct coated by epicuticle. The composition and specializations of this complex cuticular architecture differ markedly from those shown by an endoparasitic copepod detected in the digestive gland of the mussel. It does not appear that the specializations detected in the cuticle of M. gracilis lead to any histopathological alteration in host tissues. © 1994 Wiley-Liss, Inc.     

Ultrastructure of an integumental organ with probable sensory function in Paragordius varius (nematomorpha)

The cuticle of late parasitic stages of Paragordius varius (Leidy, 1851) is composed of a layer with large fibres and a second layer (often named the areolar layer) distal from it. In this paper, organs are described that start at the basal side of the epidermis, pass the epidermis and the fibrous layer of the cuticle and merge with large, cushion‐like structures in the distal layer of the cuticle. The epidermal part of the organs is composed of darkly stained cells, which are probably in contact with the basi‐epidermal nervous system. Up to four processes of this cell traverse the cuticle. These processes might include cilia, because they contain microtubule‐like structures. The probable connection to nerve cells and the connection to the cushion‐like structures in the outer cuticular layer make it likely that the organs described here are sensory in function.     

The ultrastructure of the cuticle of Nematoda. II. The cephalic cuticle of Stilbonematinae (Adenophorea,Desmodoridae)

Summary  The ultrastructure of the cephalic cuticle of 6 of 7 representative genera of Stilbonematinae (Eubostrichus, Catanema, Laxus, Robbea, Leptonemella, Stilbonema) is investigated using SEM and TEM techniques. Additionally, one species of Spirinia (Spiriniinae) and one of Desmodora (Desmodorinae) were studied for outgroup comparison. Most of the studied species show modifications of the cephalic cuticle. Furthermore, at least four different pathways have been developed to reinforce the head within Stilbonematinae. Species with a coarsely annulated somatic cuticle (Leptonemella sp., Stilbonema majum, and Desmodora ovigera) developed a rigid, non-annulated cephalic capsule by modifying the main constructing element of the median zone, the ’’ring body.’’ In faintly annulated Laxus oneistus, the annulated cephalic capsule results from a newly inserted ’’block layer’’ between the median and basal zone. The non-annulated cephalic capsule of Robbea sp. is formed by both the block layer and the ring body element. The annulated capsule of Catanema sp. stems from a doubled number of fiber layers within the basal zone. In Spirinia sp., only the amphidial region is strengthened in what could be termed an amphidial shield. All forms with cephalic capsules show mechanisms to keep the oral region pliable. Only Eubostrichus topiarius lacks a reinforcement of the cephalic cuticle. A comparison with the literature is made to elucidate corresponding structures within the cephalic capsules of representatives of Desmodorida. It is demonstrated that the presence of a cephalic cuticle is of no systematic value above the genus level. Accepted: 3 March 1996     

Calcium translocations during the moulting cycle of the semiterrestrial isopod <Emphasis Type="Italic">Ligia hawaiiensis</Emphasis> (Oniscidea,Crustacea)

Terrestrial isopods moult first the posterior and then the anterior half of the body. During the moulting cycle they retain a significant fraction of cuticular calcium partly by storing it in sternal CaCO₃ deposits. We analysed the calcium content in whole Ligia hawaiiensis and the calcium distribution between the posterior, the anterior ventral, and the anterior dorsal cuticle during four stages of the moulting cycle. The results indicate that: (1) overall, about 80% of the calcium is retained and 20% is lost with the exuviae, (2) in premoult 68% of the calcium in the posterior cuticle is resorbed (23% moved to the anterior ventral cuticle, 17% to the anterior dorsal cuticle, and the remaining 28% to internal tissues), (3) after the posterior moult 83% of the calcium in the anterior cuticle is shifted to the posterior cuticle and possibly to internal storage sites, (4) following the anterior moult up to 54% of the calcium in the posterior cuticle is resorbed and used to mineralise the new anterior cuticle. ⁴⁵Ca-uptake experiments suggest that up to 80% of calcium lost with the anterior exuviae may be regained after its ingestion. Whole body calcium of Ligia hawaiiensis is only 0.7 times that of the fully terrestrial isopods. These terrestrial species can retain only 48% of whole body calcium, suggesting that the amount of calcium that can be retained by shifting it between the anterior and posterior integument is limited. We propose that fully terrestrial Oniscidea rely to a larger degree on other calcium sources like internal stores and uptake from the ingested exuviae.     

A new species of Heth Cobb, 1898 (Nematoda: Rhigonematida: Hethidae) from an Australian millipede (Myriapoda: Diplopoda: Spirostreptida)

Abstract

A new species of nematode, Heth baudini sp. n. from a diplopod (Spirostreptida: Iulomorphidae Verhoeff, 1924) collected in Queensland, Australia, is described and illustrated. The cephalic and cervical cuticular ornamentation of females of H. baudini sp. n. is similar to those of South-East Asian and Australasian Heth species. Heth baudini sp. n. females are particularly close to Heth taynguyeni from Vietnam but can be distinguished by the shape of the lateral lappets, which in H. taynguyeni limit the trapezium-shaped region of smooth cuticle unlike the elliptical region in H. baudini sp. n., and by the presence of lateral spines only half the size. The cuticle of the H. baudini sp. n. is finely annulated along the entire body, whereas H. taynguyeni has broader rings behind the first pair of lateral spines, each consisting of five or six narrower rings separated from each other by deeper furrows. Males of H. baudini sp. n. are characterised by the presence of a bursa-like fold on the tail and can be distinguished from other species of the genus by the presence of somatic papillae embedded into the bursal fold.     

A new opuntioid cactus from the Cayman Islands, B.W.I., with a discussion and key to the genus Consolea Lemaire

A new subspecies ofConsolea millspaughii is described from the eastern bluff of Cayman Brac and northern coastal terrace of Little Cayman (Cayman Islands, British West Indies). This taxon has been mistakenly identified asConsolea spinosissima since its first collection in 1938. However, the smooth surface of its stem segments, not being demarcated by a network of depressed lines, its pitted areoles, and the fairly reduced pedicellate area of the pericarpel set is apart from this Jamaican endemic. Because the novelty here described brings to three the number ofConsolea taxa that are characterized by very closely set, pitted areoles, an informal “C. millspaughii species-group” is recognized. This assemblage of Western Caribbean opuntioids includesConsolea corallicola, C. millspaughii subsp.millspaughii, andC. millspaughii subsp.caymannnsis. The new subspecies is described, illustrated, and compared withC. spinosissima and with kindred taxa within the species-group. A key to all species and subspecies ofConsolea is provided.     

AREOLE DIMORPHISM IN CORYPHANTHA

Boke , Norman H. (U. Oklahoma, Norman.) Areole dimorphism in Coryphantha. Amer. Jour. Bot. 48(7): 593–603. Illus. 1961.—Coryphantha clava and C. erecta have both grooved and grooveless tubercles. The latter occur on young plants and emergent branches and may occur mixed with grooved tubercles on adult shoots, especially in C. erecta. Grooved tubercles have monomorphic areoles and are the only ones which bear flowers. The dimorphic areoles on grooveless tubercles develop exactly as in the mammillarias. In both species capitate glands occur in the axils of most tubercles and may occur at any position along an areole groove. The glands are initiated by the areole meristem in the same manner as spines, with which they are homologous. Close relationship between the 2 species is substantiated by both ectomorphic and endomorphic characters. The possession of both monomorphic and dimorphic areoles may mean that these cacti are evolving toward the complete areole dimorphism manifested by the mammillarias.