Cuticular Ring Research Articles

Sphenoderesjaponicus sp. nov. – The first deep water representative of the family Semnoderidae (Kinorhyncha, Cyclorhagida) in the sea of Japan

A new species of semnoderid kinorhynchs, Sphenoderes japonicus sp. nov. collected from oxidized brown silt on the steep slope of the deepest depression in the Sea of Japan, Northwestern Pacific, is described using light and scanning electron microscopy. This new representative of the family Semnoderidae is characterized by the structure of the first trunk segment consisting of externally closed cuticular ring with indistinct intracuticular tergosternal junctions. Cuticular ring of the first trunk segment is with deep and narrow middorsal incision and much broader midventral incision filled by large midventral placid. Acicular lateroventral spines on trunk segments 3–9. Lateroventral accessory spines are minute, only on trunk segment 5. Trunk segment 10 with acicular spines in laterodorsal position in female and in midlateral position in male. S. japonicus sp. nov. constitutes the first bathial species of this family and the first species of Semnoderidae in the Sea of Japan.

Sachsia putridicola n. sp. (Rhabditida: Diplogastridae), isolated from an Onthophagus dung beetle (Coleoptera: Scarabaeidae) from Tsukuba, Japan

Summary An undescribed Sachsia species (Diplogastridae) was isolated from a dung beetle, Onthophagus sp. cf. atripennis, and the species is described here as Sachsia putridicola n. sp. The new species is characterised by its cheilostom; anterior part forming a cuticular ring, posterior part in the form of a thin-walled tube; an anisotopic gymnostom, a metastegostom with dorsal small tooth and no subventral armature, and setiform male genital papillae with the arrangement <v1d, v2, v3/v4, ad, ph, v5-7, pd>. Sachsia putridicola n. sp. is typologically similar to two previously described congeners, Sachsia zurstrasseni and Sachsia postpapillata, but can be readily distinguished by its anisotopic gymnostom (vs isotopic gymnostom in the two nominal species) and the direction of the anterior three pairs of genital papillae, which are directed sublaterally in the new species (vs second or third pair directed sublaterally in S. zurstrasseni and S. postpapillata, respectively). Phylogenetically, the new species is close to Eudiplogasterium evidentum, not S. zurstrasseni. Based on the typological and phylogenetic characters, the status of S. zurstrasseni is discussed.

Three new species of Microlaimus (Nematoda: Microlaimidae) from the South Atlantic.

Three new species of Microlaimus are described from the continental shelf of the Campos Basin, southwest Atlantic, Brazil. Microlaimus campiensis sp. n. differs from all other species in the presence of two anterior testes, slender spicules with enlarged proximal ends, 7–11 pre-cloacal papilliform supplements, and females with a pair of constriction structures, one on each branch of the ovary. Microlaimus alexandri sp. n. shows sexual dimorphism in the size of the amphidial fovea, which occupies 100% of the diameter of the corresponding area in the male; the buccal cavity provided with five teeth and a slightly cuticularized cuticular ring. Microlaimus vitorius sp. n. has four longitudinal-lateral rows of glands associated with small pores, one seta and three pores small pre-cloacal, and the gubernaculum has a triangular base. An amendment to the diagnosis of the genus is proposed, where the number of teeth was modified.

Description and molecular characterisation of Pelecitus copsychi Uni, Mat Udin & Martin n. sp. (Nematoda: Onchocercidae) from the white-rumped shama Copsychus malabaricus (Scopoli) (Passeriformes: Muscicapidae) of Pahang, Malaysia

Species of the genus Pelecitus Railliet & Henry, 1910 the most widely distributed avian filariae in Africa and South America. Zoonotic cases in humans were reported in South America. While investigating the filarial fauna of wild animals in Malaysia, we discovered an undescribed filaria from the swollen footpad of the left leg of Copsychus malabaricus (Scopoli) in Pahang, Peninsular Malaysia. Adults of both sexes have a corkscrew-shaped body. Based on comparison of their morphological characteristics (i.e. pre-oesophageal cuticular ring distinct, oesophagus divided, vulva protuberant and situated at the level of anterior half of oesophagus, spicules strongly sclerotized and left spicule with broad blade) with other Pelecitus species, they are here described as Pelecitus copsychi Uni, Mat Udin & Martin n. sp. Multi-locus sequence analyses based on seven genes (12S rDNA, cox1, 18S rDNA, 28S rDNA, MyoHC, rbp1 and hsp70) were performed to determine the phylogenetic position of the new species. The calculated p-distance between the cox1 gene sequences for P. copsychi n. sp. and Pelecitus fulicaeatrae (Diesing, 1861) was 14.1%. Intraspecific genetic variation between two individuals of the new species was 0.4%. In both the Bayesian inference and maximum-likelihood trees, P. copsychi n. sp. was positioned in the second clade of ONC5, containing three genera of the subfamily Dirofilariinae (Foleyella Seurat, 1917, Pelecitus and Loa Stiles, 1905). Immunostaining and molecular analyses remained negative for the presence of Wolbachia endosymbionts. Our findings corroborate the division of the subfamily Dirofilariinae into ONC3 with Dirofilaria Railliet & Henry, 1911 and ONC5 with Pelecitus.

Three new genera and new species of hystrignathid nematodes (Nematoda: Thelastomatoidea) from passalid beetles (Insecta: Passalidae) from Yunnan Province, China with phylogenetic analysis of Hystrignathidae.

Three new genera and three new species of hystrignathid nematodes were collected from the hindgut of passalid beetles in the Yunnan Province, China. Huntia morffei gen. n. et sp. n. from Ceracupes fronticornis (Westwood) differs from related genera in the shape of the stoma, in the cephalic structure, and in the lack of annulation in the cervical region. Parakongonema sinica gen. n. et sp. n. from Aceraius grandis (Burmeister) and C. fronticornis can be easily distinguished from related genera in having the oral opening surrounded by a cuticular ring, the ring being surrounded by a cuticular flap, in the shape of the oesophagus, and in the cephalic structure. Parahystrignathus tongbiguanensis gen. n. et sp. n. from C. fronticornis and A. grandis differs from related genera by having the cervical region armed with alternating rows of spines, with 16 spines in the first row, and by lacking the first cephalic annule. In addition, the 18S and 28S rDNA partial sequences of three new species were obtained. The phylogeny of Hystrignathidae was inferred using partial sequences of the 28S rDNA and revealed patterns that suggest that the shape of the parasite digestive tract may reflect the evolutionary relationships of hystrignathid nematodes.

New record of the soft-bodied genus Franciscideres (Kinorhyncha) from Argentina, with notes on its movement and morphological variation.

Samples collected from Monte Hermoso, Buenos Aires Province, Argentina revealed the presence of specimens of the genus Franciscideres Dal Zotto et al., 2013, previously known only from Brazil. This morphotype seems to differ from the only known species, Franciscideres kalenesos Dal Zotto et al., 2013, in the following characters: (1) presence of ventrolateral tubes on segment 1, (2) introvert features, (3) each segment composed of a closed cuticular ring, (4) trunk cuticle ornamented by a secondary fringe of knob-like structures, (5) posterior margin of segment 10 ventrally terminating in two lateral and one broad triangular lobes, (6) posterior margin of segment 11 centrally terminating in four lobes (7) lateral terminal spines armed with thorn-like processes, (8) pores/sensory spots/gland cells distribution and (9) sexual dimorphism in segments 10 and 11. Because of the lack of full information about F. kalenesos from Brazil, we consider the new exemplars as Franciscideres cf. kalenesos. Additionally, we provide new information about the movement of this species using light microscopy and we compare these movements with those of other meiofaunal inhabitants.

Parasemnoderes intermedius gen. n., sp. n.—the First Abyssal Representative of the Family Semnoderidae (Kinorhyncha: Cyclorhagida)

A new genus and new species of semnoderid kinorhynchs, Parasemnoderes intermedius gen. nov., sp. nov. collected from the abyssal plane at the south border of the Kuril-Kamchatka Trench at the depth 5348 m is described and illustrated using light and electron microscopy. This new representative of the family Semnoderidae is characterized by the structure of the first trunk segment consisting of externally closed cuticular ring with indistinct intracuticular tergosternal junctions. Cuticular ring of the first trunk segment is with deep and narrow middorsal incision and much broader midventral incision filled by midventral placid. Lateroventral spines aciculate, on trunk segments 3–9. Lateroventral accessory spines are minute, only on trunk segment 5. Laterodorsal spines on trunk segment 10. Parasemnoderes intermedius gen. nov, sp. nov. constitutes the third genus the Semnoderidae described so far (Semnoderes and Sphenoderes) and the first species of this family described from the abyssal depth. The total species number of the family Semnoderidae has been increased up to 6. A key to the species of the family Semnoderidae is proposed.

Meristoderes okhotensis sp. nov. – The first deepwater representative of kinorhynchs in the Sea of Okhotsk (Kinorhyncha: Cyclorhagida)

A new species of echinoderid kinorhynchs, Meristoderes okhotensis sp. nov. collected from oxidized brown silt at Kuril Basin, the deepest depression of the Sea of Okhotsk, northwestern Pacific, is described and illustrated using light and electron microscopy. This new representative of the most recently described genus Meristoderes from the family Echinoderidae is characterized by the structure of the second trunk segment consisting of an externally closed cuticular ring with indistinct intracuticular tergosternal junctions which are remarkably curved. This segment also bears pairs of subdorsal, laterodorsal and ventrolateral adhesive tubules. Trunk segment 5 with tubules in lateroventral position. Aciculate lateroventral spines on trunk segments 6–9. Meristoderes okhotensis sp. nov. is the only representative of the genus with two middorsal spines, on trunk segments 6 and 8. This species is well recognized by its exceptionally long tergal extensions of trunk segment 11, some of the longest within all kinorhynch species. Meristoderes okhotensis sp. nov. appears the deepest representative of the family Echinoderidae described so far. It constitutes the eighth species and the first deepwater representative of the genus Meristoderes. Also, this is the first species of kinorhynchs described from the Sea of Okhotsk. A key to the species of the genus Meristoderes is proposed.

Dermal glands in freshwater mites Limnesia undulata (O.F. Müller, 1776) and Limnesia fulgida (C.L. Koch, 1836) (Acariformes, Limnesiidae)

Dermal glands in the water mites Limnesia undulata (O.F. Müller, 1776) and Limnesia fulgida (C.L. Koch, 1836) and their secretion were studied by means of light microscopical, transmission electron microscopical (TEM) and scanning electron microscopical (SEM) methods. These mites possess two types of dermal glands – the ‘common’ dermal glands in a number of 14 pairs and one pair of the so-called ‘idiosomal’ dermal glands. The common dermal glands are bi-lobed organs and consist of high prismatic secretory cells directed to the gland mouth and mostly replacing the intra-alveolar lumen. The cells contain numerous cisterns of rough endoplasmic reticulum (RER) and specifically organized Golgi bodies (GB) producing electron-dense elongated secretory granules. These granules are released from the cells via apocrine secretion and come to the gland mouth, where they are sometimes accompanied by secretory cell cytoplasm. The final secretion may show a fibrous character. The idiosomal glands are sac-like organs stretched along the ventral body wall in posterior direction from the gland orifice corresponding to the epimeroglandularia 4. The secretory epithelium leaves a large intra-alveolar lumen filled with an electron-dense secretory material. Golgi bodies are organized identically with those in the common glands, which indicates the general homology of these two types of dermal glands. The glands' orifices are organized similarly in all glands and possess an internal funnel-shaped sclerite with muscle armament, an internal valve, medial epicuticular flaps and an external circular cuticular ring. All glandularia, except for E4 and V1, are accompanied with a long and thin sensitive seta. During fixation, secretion of the common dermal glands is extruded to the exterior in the form of large amounts of convoluted tube-like structures. In the living organisms, being secreted in mass from the glands, this secretion acquires the form of long rigid mostly hollow un-branched threads comparable with the similar silken threads of other water arthropods. The function of the idiosomal glands secretion still remains unknown.

A Morphological and Molecular Study of Spectatus spectatus (Kathlaniidae), Including Redescription of the Species and Amendment of Genus Diagnosis.

Spectatus spectatus Travassos, 1923 (Nematoda: Kathlaniidae) found in the intestine of Piaractus mesopotamicus (Holmberg, 1887) (Characiformes: Serrasalmidae) from the River Miranda, Mato Grosso do Sul, Brazil is redescribed based on morphological evaluation of newly collected material and examination of type and voucher specimens from the Coleção Helmintológica do Instituto Oswaldo Cruz. The following characteristics previously unreported or insufficiently described were observed: morphology of lips, presence of lamellae-like supplementary lips, presence of pharynx and cuticular ring surrounding the oral opening associated with a complex cuticular apparatus anterior to the pharynx, the number and arrangement of caudal papillae (13 pairs plus 1 unpaired), and the position of nerve ring. Since S. spectatus is the type species of Spectatus, the diagnosis of this Neotropical genus is amended. Synonymy of Chabaudinema Díaz-Ungría, 1968 with Spectatus, first proposed in 1980 by Baker, is supported by the present data. Molecular data that include the first sequence of the SSU rDNA for any species of Spectatus indicate a basal position of S. spectatus within Cosmocercoidea, forming a distant lineage from that comprising 2 species of Falcaustra Lane, 1915. This separate position of S. spectatus supports validity of the genus.

Cucullanus egyptae sp. nov. (Nematoda, Cucullanidae) infecting the European eel Anguilla anguilla in Egypt. Morphological and molecular phylogenetic studies.

A total of 80 specimens of the European eel Anguilla anguilla were collected during the period from February 2013 to March 2014 at the coast of the Gulf of Suez (Red Sea, Egypt). A new species of parasitic nematodes was recovered and described as Cucullanus egyptae. It was found in the eel's intestine with a prevalence of 68.7%. The morphology of the recovered parasite was studied by light and scanning electron microscopy. The adult worms had a wide cephalic extremity with a slit-like oral aperture being surrounded by a cuticular ring and delimited internally by a row of small teeth in addition to four sub-median cephalic papillae and one pair of lateral amphids. Body measurements showed that the male worms were smaller than females measuring 7.5-8.9 mm (8.3 ± 0.2) in length and 1.6-1.9 mm (1.8 ± 0.1) in width. Females measured 12.9-13.5 mm (13.1 ± 0.2) in length and 2.9-3.2 mm (3.1 ± 0.1) in width. The posterior end of the males is provided with ten pairs of caudal papillae and two long spicules which are slightly sclerotized, equal in size measuring 0.59-0.65 mm (0.62 ± 0.01) in length. Comparing the present worms with other species of the genus Cucullanus, several similarities were observed. However, peculiar new characteristics such as the precloacal sucker (especially the spicula length), the arrangement and the distribution of the post-cloacal papillae, and the position of the excretory pore make it reasonable to describe a new species. The sequence data of the small subunit (SSU) ribosomal DNA (rDNA) obtained from the present nematode supported its taxonomic position within the genus Cucullanus. The new species is closely related to the first clade of Spirurina and even more closely related to Cucullanus dodsworthi as a sister taxon with a high percentage of identity. The sequence of the recorded SSU rDNA of this parasite is deposited in the GenBank with the accession no. KF681520. It is proposed to name the new species C. egyptae as the first representative of Cucullanidae in Egypt with a new host record.

The morphology, arrangement, and ultrastructure of a new type of microtrich sensilla in marine isopods (Crustacea, Isopoda)

BackgroundMicrotrich sensilla are a special type of cuticular structures found on the external surface of amphipod and isopod crustaceans. These cuticular microstructures, being important for systematic and phylogenetic studies, display a wide diversity of shapes and distribution among different taxa. Here, the microstructure of the cuticular surface of 11 marine isopod species was investigated by scanning electron microscopy.ResultsOn the dorsal and lateral sides of all the taxa examined, only one distinct type of microtrich sensillum was found in the regular rows. While this structure is very similar to that of the Ib microtrich type (sensu Crustaceana 13:100–106, 1988), however, it is distinct from the previous type, in which it has an elongate cuticular ring or specialized collar encircling the shaft base of the microtrichs. The findings indicate that different taxa of marine isopods may show a new type of microtrich sensilla differing in morphology and arrangement.ConclusionsThe findings indicate that different taxa of marine isopods may show a new type of microtrich sensilla differing in morphology and arrangement.

Meristoderes gen. nov., a new kinorhynch genus, with the description of two new species and their implications for echinoderid phylogeny (Kinorhyncha: Cyclorhagida, Echinoderidae)

A new kinorhynch genus, Meristoderes gen. nov., and two new species from Spain and the Solomon Islands, respectively, are described. The new genus is distinguished from all other genera by the first segment consisting of a closed cuticular ring, and the second segment having partial tergosternal junctions, and a superficial midventral fold. This is a new cuticular configuration that may shed light into the phylogenetic relationships of echinoderid kinorhynchs. Meristoderes macracanthus gen. et sp. nov. from the Mediterranean coast of Spain is recognised by the presence of middorsal spines on segments 4, 6 and 8, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6–9, lateral accessory tubules on segment 8, one pair of laterodorsal tubules on segment 10. Meristoderes galatheae sp. nov. from the Solomon Islands is recognized by having a middorsal spine on segment 4 only, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6–9, lateral accessory tubules on segment 8 and subdorsal tubules on segment 10. Both species have a pattern of paraventral perforation site clusters on segments 3–9, with conspicuously long bracteate hairs from the posteriormost perforations sites on the segments 3–7 and 3–6, respectively.The new genus Meristoderes gen. nov. is included into the family Echinoderidae Bütschli, 1876 and appears closely related with the genera Cephalorhyncha Adrianov, 1999 and Echinoderes Claparède, 1863. The new information it provides is discussed to clarify the internal phylogeny of Echinoderidae. The terminology for cuticular characters in the overlapping area between consecutive segments is also standardized.

A new species of the rare genus Sphenoderes (Cyclorhagida, Kinorhyncha), with differential notes on S. indicus Higgins, 1969

A new species of the rarely recorded kinorhynch genus Sphenoderes was collected in the Korea Strait and East China Sea. The new species, Sphenoderes poseidon sp. nov., is distinguished by the presence of lateroventral cuspidate spines on segments 5 and 9 only, opposed to cuspidate spines on segments 5, 8 and 9 as found in S. indicus. The new species is furthermore characterized by having the special head aperture that is diagnostic for species of Sphenoderes, but yet possessing a segment 1 composed of a single, closed cuticular ring, rather than a dorsal, a ventral and two lateral plates as found in S. indicus. The description of Sphenoderes poseidon sp. nov. includes the first scanning electron microscopical examinations of cuticular details in a species of Sphenoderes. The new information is discussed and a comparison is made with the putative closely-related species S. indicus, as well as with other species more generally across the Kinorhyncha.

Wollunquaderes majkenae gen. et sp. nov.—a new cyclorhagid kinorhynch genus and species from the Coral Sea, Australia

A new kinorhynch genus and species, Wollunquaderes majkenae gen. et sp. nov., is described from a locality in the Coral Sea, southeast of the Great Barrier Reef, Australia. The new genus and species is recognized by the presence of outer oral styles with a conspicuous fishbone-like substructure and 16 placids that articulate with segment 1 through distinct joints. Segment 1 has a completely straight anterior margin, and is composed of a closed, cuticular ring, whereas segments 2–11 are composed of one tergal and two sternal plates. The posterior segment margins of segments 2–9 form conspicuous flare-like extensions in the lateral accessory positions. Sexually dimorphic characters include presence of paired papillae on the sternal plates of segments 8 and 9 in females, and acicular spines in middorsal and sublateral positions on segment 10 in females, opposed to middorsal and midlateral crenulated spines in males. The new genus displays several traits found in species of Antygomonas and/or Semnoderes, but also characters that otherwise are considered unique for taxa of Centroderidae. Hence, Wollunquaderes gen. nov. cannot be assigned to any known family.

A new kinorhynch genus from the Antarctic deep sea and a new species of Cephalorhyncha from Hawaii (Kinorhyncha: Cyclorhagida: Echinoderidae)

A new species of a new kinorhynch genus with affinities to the Echinoderidae and a new species of Cephalorhyncha are described. Polacanthoderes martinezi gen. et sp. nov. was collected during the German ANDEEP-1 cruise at 2290 m depth north of the South Shetland Islands in the Southern Atlantic Ocean, approximately 170 km north of the Antarctic Peninsula. Polacanthoderes is characterized by the presence of a first trunk segment consisting of a complete cuticular ring, and by each of the following ten segments consisting of one tergal and two sternal plates. Cuticular hairs and perforation sites are absent, but spines are present in middorsal, subdorsal, laterodorsal, midlateral, lateral accessory, lateroventral, ventrolateral and ventromedial series on segments 4–10. The ventral side of segment 1 has a very strong and conspicuous pectinate fringe, whereas fringes are indistinct or absent on posterior segment margins of the following segments. Due to segment 1 being composed of a closed ring and the following segments of a tergal and two sternal plates, as well as to the presence of aligned middorsal spines and lateral terminal spines but absence of a midterminal spine, Polacanthoderes is assigned to the family Echinoderidae. Cephalorhyncha liticola sp. nov. was collected in the intertidal zone of a high energy beach on the northeast coast of Oahu, Hawaii. The species is characterized by the sternal plate of segment 2 being incompletely separated anteriorly by a midventral fissure. Middorsal spines are present on segments 4–8, ventrolateral spines on segment 2, lateroventral spines on segments 5–9, lateral accessory spines on segment 8, and laterodorsal spines on segment 10. In addition, there are special sensory spots with conspicuous marginal cuticular hairs on segments 1–3, and very long pectinate fringes on the sternal plates of segments 3–10. The partly subdivided sternal plates on segment 2 show the species to belong to the echinoderid genus Cephalorhyncha.

Fine structure of Chrysomya nigripes (Diptera: Calliphoridae), a fly species of medical importance

The fine structure of Chrysomya nigripes Aubertin, a blow fly species of medical importance, is presented using scanning electron microscopy (SEM) to contribute information on the morphology of the adult of this fly species. The surface of the dome-shaped ommatidia exhibits a microscopic granulose appearance. The palpus is equipped with small sensilla basiconica and sensilla chaetica, which provide sensory reception for detecting environmental information. At the apex of the mouthparts, the labellum is endowed with large numbers of sensilla trichodea and basiconic-like sensilla of variable length. The anterior (mesothoracic) spiracle is elliptical in shape and covered with extensively ramified setae except for a small dorsal aperture. The posterior (metathoracic) spiracle is shaped like a rounded isosceles triangle and covered by two valves of unequal size. The larger valve covers the upper approximately 2/3 of the spiracular opening, whereas the smaller valve covers the lower approximately 1/3 of the opening. Extensively ramified setae line and cover the valves over the entire spiracle. SEM analyses of the haltere knob and the prosternal organs, located adjacent to the cervical sclerites, revealed a striking resemblance of the morphological features of their sensilla. Each sensillum emanates from a cuticular ring, is approximately 12-15 mum in length, has a smooth surface, and terminates in a sharp tip. Various types of sensilla were associated with the ovipositor including sensilla trichodea, sensilla basiconica, sensilla placodea and probably sensilla styloconica. The possible function of sensilla distributed in particular regions of the fly integument is discussed.

Morphology and ultrastructure of sense organs on the ovipositor of Trybliographa rapae, a parasitoid of the cabbage root fly

The ovipositor of the parasitoid wasp Trybliographa rapae was examined by scanning and transmission electron microscopy. Characteristic peg-like sensilla with a cuticular ring at the base are found at the tip of the ventral valves, where they occur in a characteristic arrangement of triplets. The unusual basal structure probably protects the sensilla against damage during movement through the substrate and piercing of the host cuticle. These sensilla are each innervated by six dendrites, some of which have lamellated tips, generally considered to be characteristic of thermosensitivity. It is suggested that the remaining dendrites are gustatory, and as such probably respond to factors present in host haemolymph. A second type of peg-like sensillum is found on both the dorsal and the ventral valves. These are set in deep pits so that only the tip of the peg protrudes above the surface of the cuticle. These occur along the length of the ovipositor shaft and ultrastructural studies reveal the pegs to be innervated by a single mechanosensitive dendrite, probably monitoring the movement of the ovipositor through the substrate.

Larval development of the rhizocephalan cirripede Briarosaccus tenellus (Maxillopoda: Thecostraca) reared in the laboratory: a scanning electron microscopy study

SEM investigations of laboratory-reared larvae of Briarosaccus tenellus Boschma, 1970, revealed five naupliar instars, one more than previously described for the Rhizocephala. The external features of these and the cypris larva are described in detail. The youngest instar (NO) is characterised by a better developed furca than in subsequent stages and one additional antennulary seta. Differences in outline, shape of antennulae, and hind-body denticulation, offer the potential of individual discrimination. All the nauplii possess a transparent, hollow cuticular ring around their body. This ‘flotation collar’ represents the bulged margin of the larval head shield and is attached to the body along a delicate ridge. Three pairs of tiny pores in contact with the ridge possibly regulate inflation of the ring, but details of this mechanisms remain unknown. Due to total lecithotrophy, the nauplii of B. tenellus have limbs setation reduced to that needed for swimming only, and other feeding structures such as the labrum are also highly reduced. In the antennulae, the morphological changes in form and setation were followed from nauplius to cypris and shown to largely resemble events in ontogeny of the thoracican barnacle Semibalanus balanoides. On this basis we establish a homology scheme between antennulary setae in these two species. In both B. tenellus and S. balanoides, a naupliar seta, apically on the fourth antennulary segment develops into a conspicuous aesthetasc while one (B. tenellus) or two (S. balanoides) subapical and postaxially sited setae on the same segment develops into into four short setae in the cypris. Our study reveals that the terminology used in describing cirripede nauplius and cypris larvae is often misleading or even erroneous and improvements are suggested. Notably replacing ‘cypris carapace’ with the ontogenetically and phylogenetically more informative term ‘head shield’.

The sternal pore areas of geophilomorph centipedes (Chilopoda: Geophilomorpha)

Most geophilomorph centipedes have segmental clusters of exocrine glands whose opening pores are arranged in more or less well-defined sternal pore areas. We describe here the cuticular structures forming and/or accompanying the gland openings on the sternites and the shape of the pore areas along the body axis in representatives of most geophilomorph families. The cuticular ring around the pore may exhibit either of two forms. In Himantariidae (Himantarium) and in Dignathodontidae (Henia) the ring looks like a continuous ribbon with a visible suture, whereas in the representatives of the remaining families no suture is seen. As to the distribution of the pores on ventral surface of the body, we record the presence of pores on the last leg-bearing segment of Clinopodes flavidus, whereas that segment was described as poreless in all geophilomorphs. We also provide a taxonomic survey of shape and distribution of pore areas in the individual families, where the pore areas may take very different shapes that we regard as transformational homologues. As for the segmental distribution of sternal pore areas, there is a considerable amount of complexity along the trunk of geophilomorph centipedes, in contrast to the apparently uniform trunk structure.