Terminal Setae Research Articles

A New Record From East Malaysia: Sphaerolaimus macrocirculus (Nematoda)

A new record of Sphaerolaimus macrocirculus (Filipjev 1918) in East Malaysian coastal water was described. The species was isolated from the muddy area of Muara Tebas, Sarawak, Malaysia. A total of 47 species of Sphaerolaimus have been reported worldwide. Samples of Sphaerolaimus macrocirculus were previously recorded in the sublittoral mud area of temperate country. S. macrocirculus possesses a stout body (1.1 – 1.6 mm; De Man ratios: a (body length/body width) = 16.8 – 27.5; b (body length/oesophagus length) = 2.3 – 4.3; c (body length/tail length) = 5.6 – 8.6). The circular amphid is very clear and situated at the base of the cephalic capsule. In male, the amphid ranged from 11.3 – 14.3 μm in diameter (mean = 12.7 ± 1.3) and 0.4 c.d. (corresponding diameter). In female, the amphid ranged from 7.2 – 9.4 μm in diameter (mean 7.8 ± 0.9) and 0.2 c.d. The species is characterised by the presence of eight groups of subcephalic setae at the head region and three longer terminal setae.

Decapodid stage of Neocrangon communis (Decapoda, Crangonidae) from the eastern part of the Sea of Okhotsk

For the first time the morphology of the decapodid stage of Neocrangon communis is described in detail. The decapodid can be distinguished from those of the genera Argis, Crangon, and Mesocrangon by the morphology of their telson, antennae, antennulae, and carapace. The main distinguishing features of the decapodid of N. communis were two spines on medial line of the carapace, a short rostrum, relatively wide scaphocerite, characteristic shape and length of the terminal setae on the telson. Drawings of general view and some limbs are presented.

First stage larva of the mud shrimp Nihonotrypaea makarovi Marin, 2013 (Decapoda: Axiidea: Callianassidae) obtained in the laboratory.

First stage larva of a new mud shrimp Nihonotrypaea makarovi Marin, 2013 (Decapoda: Axiidea: Callianassidae) obtained from the ovigerous female is described and illustrated for the first time. The first zoea of N. makarovi is well distinguished from the first larvae of N. japonica and N. petalura, sympatric callianassid species inhabiting Russian waters of the Sea of Japan, only by the greater size and by the presence of two terminal setae on the antennal endopod.

A new species of the genus Elaphoidella Chappuis (Copepoda, Harpacticoida) from a cave in the south of Thailand

Specimens of a new species,Elaphoidella sanoamuangaen. sp., were collected during an investigation of cave-dwelling copepods in a tourist cave in the Phuket mountain range, South Thailand, and the new species is described and depicted herein.Elaphoidella sanoamuangaen. sp. fits intoElaphoidellagroup VII sensu Lang (1948). The new species is most similar toE. schubartiChappuis, 1936. The differential characters for females of the two species are: (a) the free margin of the anal operculum, (b) the number of ventral spinules on the anal somite, (c) the shape of the caudal rami, (d) the shape of the inner terminal caudal seta, (e) the segmentation of Endp P1, (f) the armature formula of Endp-2 P2-P4, and (g) the size of the setae on P5.

Paragnomoxyala gen. nov. (Xyalidae, Monhysterida, Nematoda) from the East China Sea

A new genus, Paragnomoxyala gen. nov., and a new species, Paragnomoxyala breviseta sp. nov. are described from the East China Sea. Paragnomoxyala gen. nov. is characterized by having large funnel-shaped buccal cavity with cuticularized walls and extended anteriorly; lips very high; striated cuticle; four cephalic setae, absence of outer labial setae; circular amphidial fovea; straight spicules and absence of gubernaculum; tail conico-cylindrical with three terminal setae; female monodelphic with an anterior outstretched ovary. It differs from similar genera by having a large buccal cavity unique in Xyalidae, straight spicules, lacking gubernaculum, and conico-cylindrical tail with terminal setae. Paragnomoxyala breviseta sp. nov. is characterized by having a large funnel-shaped buccal cavity, with cuticularized walls and extended anteriorly, 1.6-1.8 hd long and 63-79% cbd wide; four cephalic setae 3-4 µm long; circular amphids 6-9 µm in diameter; spicules straight but slightly bent at both ends; absence of gubernaculum and precloacal supplement.

English

This study was conducted to study the morphological features of species under the genus Chaetoceros isolated from the coastal waters of Pahang, Malaysia. The species were isolated, cultivated and viewed under light microscope (LM) and scanning electron microscope (SEM). Four taxa were successfully isolated and cultivated in pure culture, namely Chaetoceros affinis var. affinis, Chaetoceros affinis var. willei, Chaetoceros anastomosans and Chaetoceros baculites. Both varieties of C. affinis were considered as distinct taxa where both strains can be distinguished based on morphological characteristics. C. affinis var. affinis has a thick cell wall compared with C. affinis var. willei. C. anastomosans has special features including a silica bar on the intersection of setae and the production of mucous. The length of the aperture opening is a new record from this study. The new record obtained for C. baculites includes the size of the aperture, the terminal setae, spinal arrangement, the thinness of the cell wall and the location of the species in tropical waters. Detailed data on each species will be added to the taxonomic information for future studies.

New Record of Three Nematode Species of Genus Enoplus (Nematoda: Enoplidae) from Korea

Three unrecorded species of free-living marine nematodes, belonging to genus Enoplus Dujardin, 1845 collected from rocky intertidal seagrass on the eastern coast of Korea, are described and illustrated. Enoplus taipingensis Zhang and Zhou, 2012 is characterized by longer body size, a series of lateral setae throughout the tail in male, the presence of trumpet-shaped precloacal supplement with well-dilated proximal end, and the presence of spicules with five to eight semicircular plates. Enoplus meridionalis Steiner, 1921 is characterized by the presence of trumpetshaped precloacal supplement with slightly dilated proximal end, paired massive spicules, and tail with two pairs of stout terminal setae. Enoplus mammillatus Timm, 1959 is easily distinguished from the congeners by narrow tubular-shaped precloacal supplement. In this study, we provide detailed morphological features of three Enoplus species by differential interference contrast microscopy and scanning electron microscopy. This is the first report on the species of the genus Enoplus from the Korean waters.

Morphology and phylogeny of four species from the genus Bacteriastrum (Bacillariophyta)

:Four colonial species of the multipolar centric diatom genus Bacteriastrum – B. furcatum, B. hyalinum, B. jadranum and B. mediterraneum – were investigated using field samples from the Adriatic Sea and cultured strains obtained from these samples. Morphology and frustule ultrastructure were examined using light and electron microscopy, and nuclear-encoded large-subunit (LSU) rDNA sequences were obtained from the strains. The description of B. jadranum has been emended based on a novel mechanism of colony formation in Bacteriastrum in which cells are joined through an organic cell jacket which holds together cells in chains. Descriptions for two of the three other species were supplemented; vegetative cells of B. hyalinum have short Y spinules on the fused part of the setae and T-shaped outgrowths, and the spores of this species possess a ring of puncta and a granular surface on the exterior side of the primary valve mantle. Specific for B. furcatum is the location of pores scattered around the setae bases. No unique ultrastructural character was found for B. mediterraneum. Phylogenetic results grouped the sequences of the four species in a clade in which B. furcatum (section Sagittata) and B. hyalinum (section Isomorpha) formed a clade as sister to a clade with B. jadranum (section Isomorpha) and B. mediterraneum (section Sagittata). Apparently, neither section was monophyletic, and the supposed defining features of isomorphic terminal setae in Isomorpha and dimorphic ones in Sagittata were not synapomorphies. Nonetheless, the genus Bacteriastrum itself remained monophyletic.

A new species of the genus Arcoscalpellum (Cirripedia, Thoracica, Scalpellidae) from deep waters in the South China Sea

A new species of deep-water barnacle that belongs to the family Scalpellidae is described from the South China Sea. Arcoscalpellum liui sp. nov. is morphologically similar to Arcoscalpellum gryllum Zevina, but differs from the latter by the absence of longitudinal striae on the capitular plates and the presence of caudal appendages with few terminal setae.

Re-definition of the genus Javanisomysis Băcescu, 1992 as a subgenus in the genus Anisomysis Hansen, 1910 (Mysida, Mysidae) and a new species of the subgenus from coastal waters in Phuket, Thailand

Anisomysis (Javanisomysis) gutzui Băcescu, 1992 was reported as a characteristic species, of which the fourth male pleopod possesses an un-segmented exopod and no endopod. The species is placed in the valid genus Javanisomysis on the basis of the characteristics of the fourth male pleopod; however, the definition of the genus was insufficient. In the present paper, re-examination of the genus Javanisomysis is carried out on the basis of paratypes loaned from the depository in Romania. We found that major morphological characteristics of the types are common to those of the species of the genus Anisomysis, particularly in the forms of the antennal scale, labrum, thoracopodal endopods, and fourth male pleopod. On the basis of the present results, the genus Javanisomysis is reinstated as a subgenus in the genus Anisomysis. The subgenus Javanisomysis is allied to the subgenus Anisomysis in the forms of the body, eye, antennular peduncle, and mandibular palp, but is separable in the following characteristics: carapace armed with spinules on the antero-lateral margin; in the fourth male pleopodal exopod the first segment as long as or slightly shorter than the third segment, excluding the terminal setae; and the telson with un-articulated denticles on the lateral margin. In addition, A. (J.) similis n. sp. is described on the basis of specimens collected from Phuket, Thailand. The new species can be separated from A. (J.) gutzui as follows: the fourth male pleopod without a projection at the expanded corner on the first segment, the telson distally triangular in shape, and an undivided carpopropodus of the sixth thoracopodal endopod in females. Anisomysis (A.) thurneysseni Nouvel, 1973 also shares with the new species such remarkable features as those in the spinules on the carapace, denticles on the telson, and the length of the first segment relative to the third one in the fourth male pleopodal exopod; and accordingly this species is also considered to be a member of the subgenus Javanisomysis. This subgenus thus currently contains three species, A. (J.) gutzui Băcescu, 1992, A. (J.) similis n. sp. and A. (J.) thurneysseni Nouvel, 1973.

First record of the genus Diarthrodella Klie, 1949(Copepoda, Harpacticoida, Paramesochridae) from the Mediterranean Sea,with description of a new species from Turkey

Both sexes of Diarthrodella ergeneae sp. nov. (Copepoda, Harpacticoida, Paramesochridae), which were collected from the intertidal zone of Kurtpinari Beach along the Mediterranean coast of Turkey, are described in detail. The new species is morphologically most similar to D. convexa Kunz, 1981; D. secunda secunda Kunz, 1954; and D. lancifera Kunz, 1981 according to the setal formula of the swimming legs, but D. ergeneae sp. nov. can easily be differentiated from D. convexa by the ratio of P1 exopod/enp-1, by the lack of an inner seta on P2 enp-2, and by the shape and armature of P5; from D. secunda s. str. by having a seta on the proximal segment of A2 exopod, P3 enp-2 with inner seta, and P3 enp-3 with 2 setae and by the armature and shape of P5 and squarish caudal rami; and from D. lancifera by having 6 setae on P1 exp-2 and squarish caudal rami that bear filiform terminal setae. A key to the species of Diarthrodella is given. Investigation of the previous literature has revealed that the genus Diarthrodella has not been reported from the Mediterranean Sea so far; hence, this is the first record of the genus from the Mediterranean Sea.

Megalopa of Mesocrangon intermedia (Decapoda: Crangonidae) from the eastern part of the Sea of Okhotsk

For the first time megalopa of Mesocrangon intermedia is described. The megalopa can be distinguished from that of the Crangon and Neocrangon by the morphology of its telson and carapace. The main distinguishing features of megalopa of M. intermedia were two spines on medial line of the carapace, a relatively long rostrum, a relatively narrow antennal scale, and the distinctive length of the terminal setae on the telson. Drawings of general view and individual limbs are presented.

The new species Daptonema pumilus sp. nov. (Nematoda: Monhysterida) in Vietnam

During 2003 year, the faunal free-living aquatic nematodes of the Cam estuary, Haiphong city and the Thivai river, Cangio mangrove, Hochiminh city had been investigated. Below, the description of one new nematode species to science Daptonema pumilus sp. nov. (Monhysterida) is given. Female: The new nematode species is a small and slender worm. Cuticle thin, transverse striation shallow, hardly visible. Somatic setae and crystalloid bodies absent. Stoma funnel-shaped, not cuticularized. Amphid fovea circular, 3.0-3.5 mm in diameter, its anterior margin situated at 1.4-1.6 labial region width from anterior body end. Oesophagus slender and muscular, swollen proximally. Cardia triangular, projecting into intestinal lumen. Rectum slightly shorter than anal body diameter. Reproductive system mono-prodelphic, ovary comparatively short, situated on the left side of intestine. Oogonia arranged in one or two rows. Oviduct short and inconspicuous. Vagina oblique, shorter than corresponding body diameter. Vulva situated on the posterior part to middle part of body. Posterior uterus sack absent. Tail long, gradually narrowing, usually curved dorsally. Two terminal setae 1.0-2.0 mm long on the tail terminal. Three caudal glands arranged in tandem, spinneret oblique. Male: Similar to female in general morphology, but somewhat shorter. Reproductive system mono-orchid. Spicules length as long as cloacal body diameter. Gubernaculum with dorsal appendix. Tail slender, gradually narrowing and curved dorsally; caudal glands three, tandem, spinneret conspicuous. This new species closes to Daptonema nanus, Lorenzen, 1971, but differs in having more front location of amphidial fovea, more back location of vulva (in D. nanus V = 58% vs V = 60.7-68.7% in D. pumilus) and presence of terminal setae at the tail (in D. nanus without terminal setae).

Two new nematodes, Pseudelzalia longiseta gen. nov., sp. nov. and Paramonohystera sinica sp. nov. (Monhysterida: Xyalidae), from sediment in the East China Sea

Pseudelzalia longiseta gen. nov, sp. nov. and Paramonohystera sinica sp. nov. from subtidal sediment in the East China Sea are described. Pseudelzalia is characterized by 6 labial papillae and 10 cephalic setae, cylindrical buccal cavity, elongate (>2 anal body diameter) spicules, and conico-cylindrical tail devoid of terminal setae. It differs from Elzalia by the absence of terminal setae. Pseudelzalia longiseta sp. nov. is 647–853 μm long, has 7–8 μm long cervical setae, 11–14 μm long caudal setae, 25–41 μm long spicules about 2.1–2.7 anal diameter, and pointed tail-tip. Paramonohystera sinica possesses 12 cephalic setae, a character found in four congeners: Paramonohystera buetschlii (Bresslau and Schuurmans Stekhoven in Schuurmans Stekhoven, 1935, Paramonohystera pilosa Boucher, 1971, Paramonohystera concinna Lorenzen, 1977 and Paramonohystera halerba Fadeeva and Belogurov, 1987. It differs from P. buetschlii by shorter body (933–1023 μm versus 2000–2200 μm); from P. pilosa by the much shorter spicules (79–88 μm versus 167 μm) and narrower head (13–16 µm versus 32 µm); from P.concinna by smooth cephalic setae (versus segmented); and from P. halerba by the absence of two rows of setae on the ventral side of the tail (versus present). Based on the evaluation of nominal species, we recognize 14 valid species and provide an emended diagnosis and a tabular key for Paramonohystera.http://www.zoobank.org/urn:lsid:zoobank.org:pub:474B8F17-AED7-4078-8176-DFC499B78526

A new genus (Copepoda, Harpacticoida, Laophontidae) from Jeju Island of Korea.

A survey on the harpacticoid copepods from an intertidal zone in Hyeopjae sandy beach, Jeju Island, Korea, resulted in the discovery of an unusual laophontid, Jejulaophonte hyeopjaeensis sp. n., which cannot be placed in any extant genus within the family. To accommodate the species, a new genus of the family Laophontidae T. Scott, 1905 is proposed and fully described here. The new species is closely related to the lineage of the five primitive genera, Carraroenia McCormack, 2006, Coullia Hamond, 1973, Hemilaophonte Jakubisiak 1933, Psammoplatypus Lee & Huys, 1999, and Robustunguis Fiers, 1992 (the CCHPR-lineage) by the reduced P2 endopod, ovate shape of the female P5 exopod and sexual dimorphism in the P3 endopod. However, it displays discrepancies from the species of the CCHPR-lineage in the presence of an inner seta on P3 and P4 exp-2, four setae on P4 enp-2, and an inner seta on P3 and P4 enp-2 in the female. Furthermore, no other species within the family Laophontidae has three setae on P2 exp-3 and a seta on P2 enp-2 at the same time. The new species has sexual dimorphism in the antennule, genital segmentation and the legs from P2 to P5. The terminal seta on the second endopodal segment of P2 in the male is longer than that in the female. The endopod of P3 is 3-segmented and displays a short inner apophysis on the second segment in the male. The outer setae on the exopod of P3 and P4 are distinctly thicker and stronger in the male than in the female. Mitochondrial cytochrome oxidase subunit I (mtCOI) sequencing of the new species has been realized in order to be used in future phylogenetic analysis.

Chaetoceros atlanticus var. koreanus var. nov. (Bacillariophyta) from the East Sea of Korea and closely related taxa: insight into the ultrastructure of the setae

Chaetoceros atlanticus var. koreanus, a new variety of C. atlanticus, was collected from the East Sea of Korea on 20 August 2013. Its morphological characteristics were examined from wild material, and the new variety was compared with three closely related taxa, C. atlanticus var. atlanticus, C. atlanticus var. neapolitanus and C. atlanticus var. skeleton. The new taxon belongs to the subgenus Chaetoceros, which is characterized by numerous granular chloroplasts in the setae as well as the body of the cell and a rimoportula on each valve, and to the section Atlantica, which is characterized by a long tubular external rimoportula at the centre of each valve, terminal and intercalary setae differing in length and direction, and wide hexagonal apertures. Chaetoceros atlanticus var. koreanus shares its general morphological characteristics with three closely related species, but has rows of small poroids forming a grid pattern, a tetragonal cross-section, and perpendicular costae on the setae. These features are not seen in the three most closely related taxa, but are sometimes found in other species included in the subgenus Chaetoceros. We therefore designate C. atlanticus var. koreanus as a new variety of C. atlanticus.

Four new Paramphimonhystrella species (Nematoda: Xyalidae) from the continental slope of New Zealand.

Four new Paramphimonhystrella species are described from the continental slope of New Zealand. P. glossalga n. sp. is characterised by presence of twelve lips, large buccal cavity, males with short, heavily cuticularised spicules joined distally, and females with large postvulvar sac and hammer-shaped cuticularised piece immediately posterior to vagina. P. barbula n. sp. is characterised by narrow buccal cavity, oval-shaped amphids, conico-cylindrical tail with swollen appearance due to conspicuously enlarged caudal gland, and males with long slender spicules and small gubernaculum. P. scutula n. sp. is characterised by a lozenge-shaped buccal cavity, males with scythe-shaped spicules, females with vulva at almost two thirds of body length from anterior, and a hammer-shaped cuticularised piece immediately posterior to vagina. P. echinocauda n. sp. is characterised by buccal cavity with cylindrical anterior portion and funnel-shaped posterior portion, distal tip of slender spicules with three pointed projections, thin gubernaculum, and tail with several long setae in middle portion, two lateral setae near tail tip and one terminal seta. The presence of a hammer-shaped cuticularised piece in two species of the genus is recorded for the first time; the function of this structure is unknown. The genus diagnosis is emended and a key to all known Paramphimonhystrella species (seven in total) is provided. The present study provides the first record of the genus outside the type locality (Yellow Sea) and extends its depth distribution from <150 m to 1350 m.

Scanning electron microscopy of the cypris larvae ofCapitulum mitella(Cirripedia: Thoracica: Scalpellomorpha)

Adult specimens ofCapitulum mitellawere collected in August 2011 in the intertidal zone of Dinghai, Fuzhou, Fujian, China (26°16′N 119°48′E). The morphology of the cypris larva reared under our conditions was determined using scanning electron microscopy (SEM). Special emphasis was given to the carapace, lattice organs, antennules, thoracopods and furcal rami. The whole carapace surface is sculptured by slender ridges demarcating rectangular or irregular polygonal areas with very fine pores. The cyprid possesses five pairs of lattice organs, arranged as two anterior and three posterior pairs. The second segment carries a preaxial seta 2 and a postaxial seta 2. The third segment carries a postaxial seta 3 outside the attachment disc, whereas a postaxial disc seta, an axial disc seta and two radial disc setae are located inside the attachment disc. The attachment disc is somewhat bell shaped. A series of slender cuticular flaps forms a distinct ‘velum’ around the base of the disc. The fourth segment carries four subterminal setae and five terminal setae. The cyprid bears six pairs of biramous natatory thoracopods consisting of a protopod (coxa + basis), a two-segmented exopod and a two-segmented endopod. The cyprid possesses a rudimentary abdomen and an almost completely cleaved telson with a pair of one-segmented furcal rami. The morphology and setation of the antennules ofC. mitellaresemble those ofBalanus amphitrite(=Amphibalanus amphitrite) andMegabalanus rosa, but differ in some morphological details.

A new species of Peltidium Philippi, 1839 (Crustacea, Copepoda, Harpacticoida) from the Pacific coast of Mexico

During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific.

New species ofStygiopontius(Copepoda: Siphonostomatoida: Dirivultidae) from a deep-sea hydrothermal volcano in the New Ireland Fore-Arc system (Papua New Guinea)

A male of the new speciesStygiopontius senckenbergibelonging to the family Dirivultidae Humes & Dojiri, 1980 (Copepoda: Siphonostomatoida) and endemic to deep-sea hydrothermal vents, is described from a raised fault block structure south of Edison seamount of the New Ireland Fore-Arc system (Papua New Guinea). The copepods were collected in by box-corer during cruise SO-133 of the RV ‘Sonne’ at a depth of 1610–1625 m, 3°19′S 152°35′E. The new species belongs to a group of eight species that are separate from 21 congeners on the basis of setation of legs 1 and 4: the coxa of leg 1 has an inner seta (absent on the others) and the third exopodal segment of leg 4 has three outer spines (instead of two spines). The new species shares withS. pectinatusHumes, 1987 a pectinate maxilliped but differs from it in lacking two pectinate, terminal claw-like setae on the endopod of the antenna.