New tools for resolving phylogenies: a systematic revision of the Convolutidae (Acoelomorpha, Acoela)

Molecular sequence data, morphological characters of spermatozoa, and newly obtained morphological characters of penis musculature are used here to revise the systematics of the family Convolutidae (Acoela). Species having isodiametric penes with non-anastomosing longitudinal muscles are transferred to the family Isodiametridae fam. nov. Species with longitudinal penis muscle fibres that anastomose or cross-over each other remain in the Convolutidae. Some species of the genera Convoluta and Conaperta (Convolutidae) are transferred to the genus Isodiametra gen. nov. (Isodiametridae fam. nov.). The genus Stomatricha (Otocelididae) is transferred to the family Convolutidae. Convoluta opisthandropora (Convolutidae) is transferred to the genus Pseudohaplogonaria (Haploposthiidae). Aphanostoma sanguineum (Convolutidae) is transferred to the genus Pseudactinoposthia (Actinoposthiidae).     

Ultrastructure of sperms in Acoela (Acoelomorpha) and its concordance with molecular systematics

Abstract. The sperms of the Acoela, a group of lower worms, are filiform cells with 2 flagella incorporated into the cell body. Their axonemes can variously have 9+2, 9+1, or 9+0 patterns of microtubules; and singlet microtubules in the cell body can be arranged in axial or cortical positions. An analysis of phylogenetic relationships of acoels based on molecular characters (18S rDNA sequence data) showed that these patterns of microtubules, where known, fell into discrete monophyletic groups. To test this hypothesis, we have expanded the database of sperm characters by examining the ultrastructure of a further 10 species representing 4 acoel families. As expected, the Convolutidae fell into 2 unrelated groups: “small‐bodied convolutids”(Convoluta pulchra, Praeconvoluta tigrina, Pseudaphanostoma smithrii) having 9+2 axonemes and cortical microtubules, and “large‐bodied convolutids” (including Wulguru cuspidata) having 9+0 axonemes and axial microtubules. Also, as expected, a member of the Mecynostomidae (Paedomecynostomum bruneum) has 9+1 axonemes and axial microtubules. Members of a family that appears intermediate by molecular characters, the Otocelididae, significantly have a variety of patterns: axonemes with both 9+2 and 9+0 patterns (Notocelis gullmarensis) or just 9+2 (the other species), and either axial (Philocelis brueggemanni), both axial and cortical (N. gullmarensis) microtubules, or microtubules that bend between axial and cortical positions along the length of the sperm (Otocelis sandara). Members of the Dakuidae (Daku woorimensis) also belong to this intermediate group, having 9+2 axonemes and axial microtubules, while in a fifth otocelidid (Stomatricha hochbergi), sperm characters are like those of the “large‐bodied convolutids” (9+0 axonemes and axial microtubules). Characters of sperm morphology generally support the molecular hypothesis of relationships and confirm a suspected polyphyly of the families Convolutidae, Otocelididae, and Actinoposthiidae.     

Ciliary receptors associated with the mouth and pharynx of Acoela (Acoelomorpha): a comparative ultrastructural study

The ultrastructure and distribution of receptor cells near the mouth and (where present) the pharynx of Hofstenia miamia, Proporus bermudensis, Conaperta thela, and Convoluta convoluta (Acoela) were investigated by transmission electron microscopy and confocal laser scanning microscopy of specimens stained with a fluorescence marker for actin. Five types of monociliary receptors were identified: (1) non‐collared receptors with a single long and narrow ciliary rootlet; (2) non‐collared receptors with a wide main ciliary rootlet and a smaller posterior rootlet; (3) non‐collared receptors with a single wide and hollow ciliary rootlet with a granulated core; (4) Collar (?) receptors with obliquely radial filament bundles in the cell apex and with a single hollow ciliary rootlet composed of numerous strand‐like elements; and (5) Collar receptors lacking a striated rootlet but with a granular body (swallow's nest rootlet). While H. miamia bears the first two receptor types, P. bermudensis has receptors of type 1, 3 and 5, and Cona. thela and Conv. convoluta have receptors of type 3, 4 and 5. The density of receptors is generally highest at the anterior body tip, regardless of where the mouth is located. Most receptor types occur scattered over the whole body but type 2 receptors of H. miamia are restricted to the pharynx and mouth region. The lack of a common receptor type specific for the mouth and pharynx of the investigated species points to an independent origin of the pharynges in Hofsteniidae and in Proporidae and of the mouth tube in Convolutidae. Moreover, the homology of the so‐called collar receptors in Acoela with typical collar receptors in other invertebrates is questioned.     

Concordance of molecular and morphological data: The example of the Acoela

Morphological features of the Acoela appear to be quite plastic, including those of the copulatory organs, which provide the principle characteristics used for the systematics of this group. Consequently, classification schemes of the Acoela comprise numerous polyphyletic groupings. In this review, we detail recent revisions of acoel systematics using molecular sequence data and new and reevaluated morphological characteristics. Gene trees are discordant with traditional systematic schemes but strongly concordant with new morphological characteristics obtained through the use of transmission electron microscopy and confocal laser scanning microscopy, namely, characteristics of body-wall and copulatory organ musculature, sperm, sperm ducts, sagittocysts, and immunocytochemistry of the nervous system. This merger of molecular and morphological data has led to significant changes in acoel classification, including a major emendation of the largest family of the Acoela, the Convolutidae, whereby half of its members were transferred to a newly created family, the Isodiametridae.     

Molecular phylogeny reveals the repeated evolution of complex male genital traits in the New Zealand moth genus Izatha (Lepidoptera: Xyloryctidae)

Male genitalia are among the most rapidly evolving and divergent morphological structures and sexual selection is known to drive this phenomenon in many taxa. Because of their diversity, even within a single genus, genital characters are frequently used to infer relationships among closely‐related species. Moths within the genus Izatha (Xyloryctidae) are ideal candidates for investigating the phylogenetic patterns of genital evolution as they display great variation in male genital structure and complexity. We determined the evolutionary relationships among 31 species of Izatha by constructing a molecular phylogeny of the genus based on the mitochondrial cytochrome oxidase subunit I gene and the isocitrate dehydrogenase and carbamoylphosphate synthase domain protein nuclear genes. This allowed estimations of ancestral male genital character states and patterns of male genital diversification using maximum‐likelihood models. The genus is divided into two well‐supported clades and two poorly supported clades at the root of the phylogeny with incomplete phylogenetic resolution within two species groups, likely due to rapid speciation. Izatha display a number of apomorphic phallic traits including cornuti (sclerotized spines) which are either discharged into the female during copulation (deciduous cornuti) or fixed to the male phallus (compound and fish‐hook cornuti). Within the genus, there is a reduction of secondary genital characters – the uncus and gnathos – but an elaboration of another grasping structure, the juxta; the potential origin and functionality of these male genital traits are discussed. Overall, some male genital characters provided a good indication of species relationships; however, several parts of the complex male genitalia of Izatha show evidence of homoplasy and convergence highlighting the problems of using these traits in determining species relationships. Additionally, this convergence has highlighted that complex genital structures may evolve repeatedly and independently within a lineage.     

Comparative sperm ultrastructure in Nemertea

Although the monophyly of Nemertea is strongly supported by unique morphological characters and results of molecular phylogenetic studies, their ingroup relationships are largely unresolved. To contribute solving this problem we studied sperm ultrastructure of 12 nemertean species that belong to different subtaxa representing the commonly recognized major monophyletic groups. The study yielded a set of 26 characters with an unexpected variation among species of the same genus (Tubulanus and Procephalothrix species), whereas other species varied in metric values or only one character state (Ramphogordius). In some species, the sperm nucleus has grooves (Zygonemertes virescens, Amphiporus imparispinosus) that may be twisted and give a spiral shape to the sperm head (Paranemertes peregrina, Emplectonema gracile). To make the characters from sperm ultrastructure accessible for further phylogenetic analyses, they were coded in a character matrix. Published data for eight species turned out to be sufficiently detailed to be included. Comparative evaluation of available information on the sperm ultrastructure suggests that subtaxa of Heteronemertea and Hoplonemertea are supported as monophyletic by sperm morphology. However, the data do not provide information on the existing contradictions regarding the internal relationships of “Palaeonemertea.” Nevertheless, our study provides evidence that sperm ultrastructure yields numerous potentially informative characters that will be included in upcoming phylogenetic analyses. J. Morphol. 2010. © 2010 Wiley‐Liss, Inc.     

Molecular systematics of the Acoela (Acoelomorpha,Platyhelminthes) and its concordance with morphology

The phylogenetic relationships of the lower worm group Acoela were investigated using newly obtained nuclear 18S rDNA sequences from 16 acoels in combination with 16 acoel sequences available on GenBank from other laboratories. Parsimony and maximum likelihood analyses of the molecular data supported the concept that the Acoela is monophyletic; however, the gene tree produced by these analyses conflicts with the current taxonomic system for the Acoela in several family-level groupings. Most notable is the apparent polyphyly of the largest family of acoels, the Convolutidae. DNA analysis grouped together species of small-bodied convolutids in one clade, while large-bodied convolutids grouped in a separate clade with other large-bodied acoels. Despite such conflicts, the branching pattern in the gene tree is well supported by morphological characters of sperm and body-wall musculature.     

Patterns of musculature as taxonomic characters for the Turbellaria Acoela

While turbellarians are generally assumed to have body-wall musculature consisting routinely of longitudinal, circular, and diagonal fibers, members of the Acoela examined by a fluorescence-microscopy technique specific for actin showed more complicated and distinctive arrangements of muscles, giving promise for better delimiting taxa within this taxonomically difficult order. Certain globose or tear-drop-shaped worms such as Convoluta pulchra and species of Pseudaphanostoma, Mecynostomum, and Otocelis, showed a complex pattern in which muscles longitudinal in the anterior half of the body arc diagonally across the posterior half; complex brushes of parenchymal muscles that cross at the level of the statocyst and arc postero-laterally also characterize these groups. The more elongate acoel Paratomella sp. was found to have musculature dominated by strictly longitudinal fibers and with relatively weak circular fibers and few fibers running diagonally to the body axis, yet the elongate mecynostomid Paedomecynostomum bruneum showed a crossing of antero-longitudinal fibers similar to that seen in the more globose Mecynostomum sp. A distinctive looping of muscles around the mouth is seen in P. bruneum and the Anaperidae. Such similarities and differences in pattern of musculature promise to provide easily recognizable characters for taxonomy of the Acoela at levels ranging from species to family. This revised version was published online in July 2006 with corrections to the Cover Date.     

Transition from monogyny to polygyny in Nephila senegalensis (Araneae: Nephilidae) is not accompanied by increased investment in sperm

A common male adaptation to prevent sperm competition is the placement of a mating plug. Such plugs are considered as an extreme investment if they comprise parts of the genital systems and render the male sterile. Genital mutilation occurs in monogynous spiders of several families and may co‐occur with permanent sperm depletion, meaning that sperm production is terminated once males become mature. Within the orb‐web spider genus Nephila, monogynous mating strategies are considered ancestral, although some species have reverted to a polygynous mating strategy. Although genital mutilation does not occur in these species, permanent sperm depletion (PSD) remained. We compared investment in sperm between an effectively plugging (Nephila fenestrata Thorell, 1859) and a closely‐related nonplugging species [Nephila senegalensis (Walckenaer, 1841)]. Sperm investment should be higher in N. senegalensis because males are able to mate with several females, whereas N. fenestrata males can only achieve a maximum of two copulations, generally performed with the same female. The absence of a plugging mechanism in N. senegalensis and the inability to monopolize females by means of mating plugs results in a higher risk of sperm competition. Thus, we predicted higher investment in sperm producing tissue and larger sperm storage organs in males of N. senegalensis compared to N. fenestrata. We examined the testes and deferent ducts of both species for size and cell‐quality differences using light and transmission electron microscopy and analyzed the volume of the sperm reservoir in the male copulatory organ (i.e. spermophor) using X‐ray microcomputed tomography. In contrast to our prediction, the lumen of testes, deferent ducts, and spermophor of N. senegalensis males were significantly smaller than in N. fenestrata.     

Male genital organs in the eulittoral meiofaunal polychaete <Emphasis Type="Italic">Stygocapitella subterranea</Emphasis> (Annelida,Parergodrilidae): ultrastructure,functional and phylogenetic significance

The marine interstitial polychaete Stygocapitella subterranea is characterized by aberrant morphological and biological traits resembling those of clitellates and Hrabeiella periglandulata, a terrestrial polychaete species. Although clearly related to the terrestrial Parergodrilus heideri, there are distinct differences in their morphology. An ultrastructural study of the male genital organs was undertaken to look for common apomorphic features in Parergodrilidae, to find structural evidence for clarifying their reproductive biology and mode of sperm transfer. Finally it should be elucidated whether a supposed sister-group relationship of Parergodrilidae and Orbiniidae based on molecular evidence can be supported by morphological characters as well. In S. subterranea the male organs consist of an unpaired seminal vesicle, a pair of sperm ducts and two large tube-like prostate glands. These glands constitute the distal parts of the gonoducts and open ventrally on a small genital papilla in chaetiger 9. True copulatory organs or organs for storage of mature sperm are lacking. The seminal vesicle is a coelomic cavity composed of two apposed coelomic linings supplied with blood spaces. The testes are found ventrally. The prostate glands are covered by a single layer of muscle fibres running in a longitudinal/spiral direction along the gland. There are no signs of spermatophore formation in any part of the male system. Since females always carry sperm, pseudocopulation can be excluded and the likelihood of either direct transfer of sperm or hypodermic injection is discussed. The structure of genital organs reveals similarities to those of P. heideri. Gonochorism, paired seminal vesicles and two pairs of male gonoducts opening in chaetigers 9 and 10 with a distal glandular part most likely belong to the ground pattern of Parergodrilidae. The observations confirm that consistencies with either clitellates or H. periglandulata are the result of convergent evolutionary events. On the other hand, the relationship of Parergodrilidae to an orbiniid/questid clade receives support from the present data. This paper is dedicated to our scientific teacher, Professor Wilfried Westheide, who made significant contributions to the reproductive biology of interstitial polychaetes, on the occasion of his 70th birthday.     

Ultrastructural observations on the spermatozoa of a species of <Emphasis Type="Italic">Lepidodasys</Emphasis> (Gastrotricha,Macrodasyida)

The ultrastructure of the spermatozoon of a species in the marine gastrotrich genus Lepidodasys is described. The filiform cell is composed of a cork-screw acrosome, a long single mitochondrion surrounded by a helical nucleus, and a flagellum with a 9 × 2 + 2 axonemal arrangement. The structure of the sperm of this species from Denmark appears closely similar to those of the other two species of Lepidodasys studied so far from Italy and Florida (US). Peculiar features (cylindrical nucleus, absence of a periaxonemal sheath) place this genus far from the others in the family Lepidodasyidae. The absence of synapomorphies between Lepidodasys and other genera of Lepidodasyidae suggests that the family is polyphyletic. The sperm ultrastructure fully fits the species of Lepidodasys into the marine order Macrodasyida, with the sperm ground plan of which its sperm shares a number of details.     

Complex copulatory behavior and the proximate effect of genital and body size differences on mechanical reproductive isolation in the millipede genus Parafontaria

The role of species-specific genitalia in reproductive isolation is unclear. Males of the millipede genus Parafontaria use gonopods (modified eighth legs) charged with sperm from the genital openings of the second legs as intromittent organs. Males perform both preliminary and true intromission during mating. During preliminary intromission, a male attempts to insert his gonopods into the female genitalia before charging the gonopods with sperm. If this intromission is completed, it is followed by the ejaculation of sperm to the gonopods and true intromission for insemination. In two sympatric species of Parafontaria that lack effective precopulatory isolation, copulation was terminated without insemination because of preliminary intromission failure caused by mismatched genital and body sizes. Thus, mechanical isolation between these sympatric species resulted from morphological differentiation mediated by the obligatory preliminary intromission. These findings demonstrate the proximate importance of genital and body size differences for reproductive isolation within this genus of millipede.     

How the worm got its pharynx: phylogeny, classification and Bayesian assessment of character evolution in Acoela

Acoela are marine microscopic worms currently thought to be the sister taxon of all other bilaterians. Acoels have long been used as models in evolutionary scenarios, and generalized conclusions about acoel and bilaterian ancestral features are frequently drawn from studies of single acoel species. There is no extensive phylogenetic study of Acoela and the taxonomy of the 380 species is chaotic. Here we use two nuclear ribosomal genes and one mitochondrial gene in combination with 37 morphological characters in an analysis of 126 acoel terminals (about one-third of the described species) to estimate the phylogeny and character evolution of Acoela. We present an estimate of posterior probabilities for ancestral character states at 31 control nodes in the phylogeny. The overall reconstruction signal based on the shape of the posterior distribution of character states was computed for all morphological characters and control nodes to assess how well these were reconstructed. The body-wall musculature appears more clearly reconstructed than the reproductive organs. Posterior similarity to the root was calculated by averaging the divergence between the posterior distributions at the nodes and the root over all morphological characters. Diopisthoporidae is the sister group to all other acoels and has the highest posterior similarity to the root. Convolutidae, including several "model" acoels, is most divergent. Finally, we present a phylogenetic classification of Acoela down to the family level where six previous family level taxa are synonymized.     

From acaveate to caveate: evolution of pollen types in the Rhaponticum group (Asteraceae,Centaureinae) related to extreme conditions

A survey of pollen morphology and ultrastructure within the Rhaponticum group, using both scanning and transmission electron microscopy, revealed two pollen types. Most representatives of the Rhaponticum group exhibited Serratula‐type pollen. The exceptions were the genus Oligochaeta, with Centaurea jacea‐type pollen, and the genus Myopordon, with both types of pollen. Phylogenetic inference within the group indicated that Jacea‐type pollen is derived from Serratula‐type pollen. The fact that Myopordon exhibited a series of pollen types, from Serratula type to Jacea type, suggests that a transition from one form to another has occurred in the genus. Therefore, the factor which has produced this evolutionary tendency should be sought within Myopordon. Jacea‐type pollen is characterized by a decrease in size, ornamentation, the absence of a columellar infratectum and the presence of a cavea. A comparative survey of similar tendencies in other groups, and their correlation with potential functional implications, prompted the hypothesis that the critical factor involved in such evolution of pollen could be habitats with extreme conditions. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 499–510.     

Is the Profile of Fatty Acids,Tocopherols, and Amino Acids Suitable to Differentiate Pinus armandii Suspicious to Be Responsible for the Pine Nut Syndrome from Other Pinus Species?

Pinus armandii is suspicious to be responsible for the Pine Nut Syndrome, a long lasting bitter and metallic taste after the consumption of pine nuts. To find chemical characteristic features for the differentiation of P. armandii from other Pinus species, 41 seed samples of the genus Pinus from 22 plant species were investigated regarding the content and the composition of fatty acids, tocopherols, and amino acids. The predominant fatty acids in the seed oils were linoleic acid (35.2 – 58.2 g/100 g), oleic acid (14.6 – 48.5 g/100 g), and pinolenic acid (0.2 – 22.4 g/100 g), while the vitamin‐E‐active compounds were dominated by γ‐tocopherol. The amino acid composition was mainly characterized by arginine and glutamic acid with amounts between 0.9 and 8.9 g/100 g as well as 2.1 g/100 g and 8.3 g/100 mg. On the basis of this investigation, a Principle Component Analysis has been used to identify the most important components for the differentiation of P. armandii from other Pinus species. Using the data for glutamic acid, 20:2Δ^5,11, 18:3Δ^5,9,12, 18:1Δ⁹, and oil content, a classification of the 41 samples into four different groups by cluster analysis was possible, but the characteristic features of P. armandii were too close to some other members of the genus Pinus, making a clear differentiation of this species difficult. Nevertheless, the investigation showed the similarities of different members of the genus Pinus with regard to fatty acids, vitamin‐E‐active compounds, and amino acids.     

New insight into the identification and molecular phylogeny of dagger nematodes of the genus Xiphinema (Nematoda: Longidoridae) with description of two new species

The genus Xiphinema constitutes a large group of about 260 species of plant‐ectoparasitic nematodes. The group is polyphagous and distributed almost worldwide. Some of the species of this genus damage agricultural crops by direct feeding on root cells as well as by transmitting nepoviruses. Species discrimination in Xiphinema is complicated by phenotypic plasticity leading to potential misidentification. We conducted nematode surveys in cultivated and natural environments in Spain from 2009 to 2012, from which we identified 20 populations of Xiphinema species morphologically close to the virus‐vector nematode species Xiphinema diversicaudatum, three apomictic populations tentatively identified as species from the complex Xiphinema aceri‐pyrenaicum group, and one population morphologically different from all others that is characterized by a female tail elongate to conical and absence of uterine differentiation. We developed comparative multivariate analyses for these related species by using morphological and morphometrical features together with molecular data from nuclear ribosomal DNA genes [D2‐D3 expansion segments of large ribosomal subunit 28S, internal transcribed spacer 1 (ITS1), and partial small ribosomal subunit (18S)]. The results of multivariate, molecular, and phylogenetic analysis confirmed the morphological hypotheses and allowed the delimitation and discrimination of two new species in the genus described herein as Xiphinema baetica sp. nov. and Xiphinema turdetanensis sp. nov. , and ten known species: Xiphinema adenohystherum, Xiphinema belmontense, Xiphinema cohni, Xiphinema coxi europaeum, Xiphinema gersoni, Xiphinema hispidum, Xiphinema italiae, Xiphinema lupini, Xiphinema nuragicum, and Xiphinema turcicum. Multivariate analyses based on quantitative and qualitative characters and phylogenetic relationships of Xiphinema spp. based on the three molecular ribosomal markers resulted in a partial consensus of these species grouping as nematode populations were maintained for the majority of morphospecies groups (e.g. morphospecies groups 5 and 6), but not in some others (e.g. position of Xiphinema granatum), demonstrating the usefulness of these analyses for helping in the diagnosis and identification of Xiphinema spp. The clade topology of phylogenetic trees of D2‐D3 and partial 18S regions in this study were congruent in supporting the polyphyletic status of some characters, such as the female tail shape and the degree of development of the genital system in species with both genital branches equally developed. This is the most complete phylogenetic study for Xiphinema non‐americanum‐group species. Agreement between phylogenetic trees and some morphological characters (uterine spines, pseudo‐Z organ, and tail shape) was tested by reconstruction of their histories on rDNA‐based trees using parsimony and Bayesian approaches. Thus, integrative taxonomy, based on the combination of multivariate, molecular analyses with morphology, constitutes a new insight into the identification of Xiphinema species. © 2013 The Linnean Society of London     

Gonad morphology,gametogenesis, and reproductive modes in fishes of the tribe Starksiini (Teleostei,Blenniiformes)

A comparative study of the reproductive organs in 17 of the 30 species of the tribe Starksiini (Labrisomidae, Blenniiformes) and related labrisomids reveals the major traits of gamete form and production and likely reproductive modes. The testes are of the lobular type and have a testicular gland and sperm ducts. Isodiametric sperm (aquasperm) with a globular head or anisodiametric sperm (introsperm) with an elongate head, or both, were observed in the studied species. Both types have either one or two flagella in the sperm tail. Ovaries of the Starksiini are bilobed and exhibit synchronous or asynchronous egg production. Although viviparity or “ovoviviparity” reportedly characterizes the group, our study revealed evidence of both internal and external fertilization and three modes of reproduction. External fertilization or ovuliparity is suggested for the Starksia atlantica and S. lepicoelia species complexes by the presence in males of a short genital papilla that is not reinforced through adhesion with the first anal‐fin spine and by the absence of sperm within the ovaries. Internal fertilization and zygoparity is indicated for most species by the presence of an intromittent papilla in males that is adhered to the first anal‐fin spine, “nests” of sperm within the ovaries, absence of embryos within the ovarian lamellae and usually thick egg envelopes bearing dense covers of adhesive filaments. Internal fertilization and embryoparity is indicated for starksia fulva and Xenomedea rhodopyga by an intromittent papilla that is adhered to the first anal‐fin spine of males, anisodiametric sperm in males, delicate egg envelopes without adhesive filaments and developing embryos within follicular envelopes or within the follicle in females. Although many of these features are seen in the internally fertilizing clinid blennies, starksiins differ in retaining the testicular gland typical of labrisomids and in lacking sperm packaging typical of other internally fertilizing teleosts. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc.     

Histochemical evidence of β‐chitin in parapodial glandular organs and tubes of Spiophanes (Annelida,Sedentaria: Spionidae), and first studies on selected Annelida

A generic character of the genus Spiophanes (Annelida, Sedentaria: Spionidae) is the presence of parapodial glandular organs. Parapodial glandular organs in Spiophanes species include secretory cells with cup‐shaped microvilli, similar to those present in deep‐sea inhabiting vestimentiferans and frenulate Siboglinidae. These cells are supposed to secrete β‐chitin for tube‐building. In this study, transverse histological and/or ultrathin sections of parapodial glandular organs and tubes of Spiophanes spp. as well as of Glandulospio orestes (Spionidae) and Owenia fusiformis (Oweniidae) were examined. Fluorescent markers together with confocal laser scanning microscopy, and Raman spectroscopy were used to detect chitin in the parapodial glandular organs of Spiophanes and/or in the glands of Owenia and Glandulospio. Tubes of these taxa were tested for chitin to elucidate the use of it for tube‐building. The examinations revealed a distinct labelling of the gland contents. Raman spectroscopy documented the presence of β‐chitin in both gland types of Spiophanes. The tubes of Spiophanes were found to have a grid‐like structure that seems to be built with this β‐chitin. Tests of tubes of Dipolydora quadrilobata (Spionidae) for chitin were negative. However, the results of our study provide strong evidence that Spiophanes species, O. fusiformis and probably also G. orestes produce chitin and supposedly use it for tube‐building. This implies that the production of chitin and its use as a constituent part of tube‐building is more widespread among polychaetes as yet known. The histochemical data presented in this study support previous assumptions inferring homology of parapodial glandular organs of Spionidae and Siboglinidae based on ultrastructure. Furthermore, transmission electron microscopy‐based evidence of secretory cells with nail‐headed microvilli in O. fusiformis suggests homology of parapodial grandular organs across annelids including Sipuncula. J. Morphol. 276:1433–1447, 2015. © 2015 Wiley Periodicals, Inc.