Convex Conoid Research Articles

Two new species of the genus Sectonema Thorne, 1930 (Nematoda, Dorylaimida, Aporcelaimidae) from Iran, with new insights into its evolutionary relationships.

Two new species of the genus Sectonema found in northern Iran are characterized, including morphological descriptions and molecular (18S-, 28S-rDNA) analyses. Sectonema tehranense sp. nov. is distinguished by its 7.22 - 8.53 mm long body, lip region offset by constriction and 24 - 31 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, mural tooth 15.5 - 17 μm long at its ventral side, neck 1091 - 1478 μm long, pharyngeal expansion occupying 61 - 71% of the total neck length, female genital system diovarian, uterus simple and 3.9 - 4.2 times the corresponding body diameter long, transverse vulva (V = 49 - 59), tail short and rounded (44 - 65 μm, c = 99 - 162, c' = 0.6 - 0.8), spicules 111 - 127 μm long, and 7 - 10 spaced ventromedian supplements with hiatus. Sectonema noshahrense sp. nov. displays a 4.07 - 4.73 mm long body, lip region offset by constriction and 23 - 25 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, odontostyle 14 - 14.5 μm long, neck 722 - 822 μm long, pharyngeal expansion occupying 66 - 68% of the total neck length, female genital system diovarian, uterus simple and 2.4 - 2.7 times the corresponding body diameter long, transverse vulva (V = 54 - 55), tail convex conoid (39 - 47 μm, c = 91 - 111, c' = 0.8 - 0.9), spicules 82 μm long, and seven spaced ventromedian supplements with hiatus. Molecular analyses confirm a maximally supported (Epacrolaimus + Metaporcelaimus + Sectonema) clade and a tentative biogeographical pattern, with sequences of Indolamayan taxa forming a clade separated from those of Palearctic ones. Parallel or convergent evolution processes might be involved in the phylogeny of the species currently classified under Sectonema. This genus is certainly more heterogeneous than previously assumed.

Morphological and molecular characterization of Aporcella femina sp. n. (Dorylaimida, Aporcelaimidae) from Nigeria.

A new species of the genus Aporcella collected from a watermelon field in Nigeria is described, including its morphological and molecular (small subunit (SSU) and large subunit (LSU) ribosomal DNA (rDNA)) characterization. Aporcella femina sp. n. is distinguished by its 3.21-3.64 mm-long body, inner cuticle layer with fine but distinct transverse striation, lip region offset by deep constriction, 22-25 μm broad, odontostyle 20-26 μm, neck 661-811 μm long, pharyngeal expansion occupying 52-56% of the total neck length, female genital system didelphic-amphidelphic, uterus 191-350 μm or 1.9-3.3 mid-body diameters long, V = 52-57, tail short and convex conoid (35-48 μm, c = 72-98, c' = 0.7-0.9) and males absent. Phylogenetic analyses based on the partial sequence of SSU and LSU (D2-D3) rDNA revealed a close relationship of A. femina sp. n. with other Aporcella species, confirming the monophyly of the genus as well as its association to a clade made of several taxa characterized by the absence of pars refringens vaginae.

Morphological and molecular characterisation of Aporcelaimellus nigeriensis sp. n. (Dorylaimida: Aporcelaimidae), a remarkable dorylaim from Nigeria

Summary A new species of Aporcelaimellus, collected in a watermelon field in Nigeria, is described, including its morphological and molecular (D2-D3 28S-rDNA, 18r-DNA) characterisation. Aporcelaimellus nigeriensis sp. n. is distinguishable by its 2.76-3.55 mm length, very coarse ventral body pores, lip region offset by deep constriction and 24-27 μm broad odontostyle 30-36 μm long at its dorsal and 28-31 μm at its ventral side, neck 648-779 μm long, pharyngeal expansion occupying 54-60% of total neck length, uterus 300-473 μm or 2.1-3.2 body diam. long and tripartite, V = 49-54, tail short and convex conoid (27-41 μm, c = 72-115, c′ = 0.5-0.7), spicules 108-137 μm long, and 9-10 spaced ventromedian supplements with hiatus. LSU analysis revealed a close relationship of A. nigeriensis sp. n. with other Aporcelaimellus species and questioned, once more, the monophyly of Aporcelaimidae. SSU phylogenetic tree was not able to resolve the relationship between the new species and other closely related species.

Taxonomy of the Genus Lordellonema Andrássy, 1960 (Nematoda: Dorylaimida: Qudsianematidae) with Description of Three New Species

Three new species of the genus LordellonemaAndrassy, 1960 are described and illustrated. Lordellonema indicumsp. nov. has 0.9–1.1 mm long body; lip region offset by constriction with distinctly protruding labial papillae; odontostyle 13–15 µm long, with aperture occupying about 40–50% of its length; vulva pore-like; tail short, rounded and males absent. Lordellonema paramacrodorumsp. nov. has 1.0–1.2 mm long body; lip region distinctly offset, lips separate, rounded; odontostyle sinuate, 27–29 µm long, with aperture occupying about one-third of its length; vulva transverse; well-developed glandular cells present close to vagina; tail conical with rounded tip. Lordellonema spicularissp. nov. is characterized by its 1.2–1.4 mm long body; lip region angular, offset by constriction; odontostyle 15–16 µm long, aperture occupying 36–44% of its length; vulva transverse; tail convex conoid with blunt terminus; males with non-dorylaimid spicules, 5–7 irregularly spaced ventromedian supplements and lateral guiding pieces absent. Lordellonema porosum is redescribed here after more than five decades from Cabo Verde. L. rapsoides (Heyns et Lagerway, 1965) comb. nov. is redescribed here from Saudi Arabia. A diagnostic compendium of valid species is provided and comment has been made on their biogeography.

Paractinolaimus persicus sp. n. (Nematoda: Actinolaimidae) from Iran.

A new species of the genus Paractinolaimus, namely, Paractinolaimus persicus sp. n., is described. It is characterised by body 2.3-2.6 mm long; low, truncate lip region; four massive, acute onchia; stoma walls covered with sparse tiny denticles; odontostyle 25-28 μm long; well developed, didelphic-amphidelphic female reproductive apparatus; vulva a longitudinal oval pore; absence of advulval papillae; female tail 146-224 µm long (c' = 3.3-5.9), elongated filiform, curved ventrad, and with acute terminus; male tail convex conoid with blunt terminus; and 17-18 nearly contiguous ventromedian supplements. This species was recovered from the rhizosphere of wild grass. Line drawings, LM and SEM photographs and measurements are provided.

Aporcella charidemiensis sp. n. (Dorylaimida: Aporcelaimidae) from the southern Iberian Peninsula, with comments on the phylogeny of the genus

Aporcella charidemiensis sp. n. is described from the southern Iberian Peninsula. It is characterised by its 1.38-1.81 mm long body, lip region offset by constriction and 16-17 μm broad, odontostyle 12-13 μm long with aperture occupying 65-73% of its length, 354-420 μm long neck, pharyngeal expansion 164-212 μm long or 46-51% of total neck length, uterus a simple tube-like structure 79-155 μm long or 1.7-3.0 times the corresponding body diam., pars refringens vaginae absent, transverse vulva (V = 53-62), convex conoid tail (24-35 μm, c = 46-69, c′ = 0.8-1.1), 59-63 μm long spicules, and 7-10 irregularly spaced ventromedian supplements bearing a hiatus. The analyses of LSU-DNA sequences of the new species confirm the previous results regarding the phylogeny of the genus Aporcella.

Characterization of European Populations ofAporcella vitrinus(Thorne Et Swanger, 1936) with Sem Observations and First Report of Its Male (Nematoda: Dorylaimida: Aporcelaimidae)

Abstract. European populations of Aporcella vitrinus, mainly collected in natural habitats of southeastern Iberian Peninsula are studied and described, including SEM observations and the first report of the male. They are characterized by its body 1.20–1.86 mm long, lateral chord bearing gland bodies, lip region offset by weak constriction and 11–13 µm broad, odontostyle 12–13 µm long, neck 333–374 µm long, pharyngeal expansion 149–185 µm long or 44–51% of total neck length, uterus simple and 28–48 µm long or 0.6–1.2 times the corresponding body diameter, pars refringens vaginae absent, V = 48–53, tail convex conoid (21–31 µm, c = 45–77, c' = 0.9–1.4), spicules 43 µm long, and six irregularly spaced ventromedian supplements with hiatus. European specimens are compared to type American ones, but do not differ significantly from these although morphometrical ranges are wider in European material. SEM pictures show a symmetrically biradial lip region pattern, totally similar to that found in Aporcelaimellus.

Studies on the genus Aporcelaimellus Heyns, 1965 (Nematoda, Dorylaimida, Aporcelaimidae). Four new species with complex uterus from Southeastern Iberian Peninsula

Four new species with complex uterus of the genus Aporcelaimellus, collected mainly in natural areas in the IberianPeninsula, are identified and described here. Aporcelaimellus alpujarrensis sp. n. is characterized by having body1.72–1.91 mm long, lip region offset by constriction and 14–15μm broad, odontostyle 14–16μm long with apertureoccupying 67–70% its length, neck about 455μm long, pharyngeal expansion about 224μm long, uterus tripartite and145–206μm long, V = 53–55, tail convex conoid (27–34μm, c = 55–71, c’ = 0.9–1.1), spicules 56–60μm long, and 7–9irregularly spaced ventromedian supplements with hiatus. Aporcelaimellus castaneanus sp. n. is characterized by havingbody 2.18–2.83 mm long, lip region offset by constriction and 20–23μm broad, odontostyle 22–24μm long with apertureoccupying 62–67% its length, neck 581–662μm long, pharyngeal expansion 300–355μm long, uterus tripartite and164–348μm long, V = 52–58, tail conical with rounded terminus (44–52μm, c = 48–60, c’ = 0.8–1.1), spicules 94–103μm long, and 14–15 irregularly spaced ventromedian supplements which lack hiatus. Aporcelaimellus communis sp. n. ischaracterized by having body 2.56–4.22 mm long, lip region offset by constriction and 19–25μm broad, odontostyle19–26μm long with aperture occupying 64–74% its length, neck 595–750μm long, pharyngeal expansion 321–427μmlong, uterus bipartite and 190–450μm long, V = 51–60, tail short and convex conoid (29–50μm, c = 63–109, c’ = 0.5–1.0),spicules 89–118μm long, and 16–25 irregularly spaced ventromedian supplements with hiatus. Aporcelaimellus tenuis sp.n. is characterized by having body 1.89–2.70 mm long and comparatively slender (a = 35–49), lip region offset byconstriction and 15–18μm broad, odontostyle 15–21μm long with aperture occupying 60–70% of its length, neck488–645μm long, pharyngeal expansion 251–366μm long, uterus bipartite and 135–213μm long, V = 55–58, tail convexconoid with rounded terminus (25–40μm, c = 64–92, c’ = 0.8–1.1), spicules 52–66μm long, and 11–12 irregularly spaced SEM pictures, are given for the four species.ventromedian supplements with hiatus. Measurements and illustrations, including line drawings, LM pictures and and/or

The genus Paradorylaimus Andrássy, 1969 (Nematoda: Dorylaimida) with description of three new species from Ecuador

Three new species of Paradorylaimus Andrássy, 1969, found in moss and litter of natural environments of Ecuador aredescribed. P. andinus sp. n. is characterized by 1.65–2.26 mm long female body, lip region set off by a depression, odontostyle26.5–32. 5 μm long and 3.0–4.5 µm wide; pre-rectum 1.1–2.4 anal body diameters long in female and 1.2–2.3 in male; 0–3 pre-vulval and 0–5 postvulval papillae; spicules 60–80 µm long; 13–14 ventral supplements; female tail elongate-filiform, 6–10anal body diameters long; male tail short, 0.7–1 cloacal body diameters long, dorsally convex, with a marked ventral concavityand blunt terminus. P. longicaudatus sp. n. is characterized by 1.78–2.14 mm long female body, lip region slightly set off by adepression, odontostyle 30–32.5 μm long and 2.0–3.5 µm wide; pre-rectum 1.3–2.3 anal body diameters long in female and 2–3.5 in male; paravulval papillae absent; spicules 44.5–62.5 µm long; 11–13 ventral supplements; female tail elongate-filiform,11–16 anal body diameters long; male tail short, 0.8–0.9 cloacal body diameters long, convex conoid, with blunt terminus. P.flagellicaudatus sp. n. is characterized by 1.65–1.73 mm long female body, lip region continuous, odontostyle 19–24 μm longand 2–2.5 µm wide; pre-rectum 1.8–2.6 anal body diameters long in female and 2.4 in male; spicules 45 µm long; 10 ventralsupplements; female tail elongate-filiform, 25–26 anal body diameters long; male tail short, conoid, 0.8 cloacal body diameterslong. The authors support the validity of the genus Paradorylaimus, provide an updated diagnosis and furnish a compendium of the main morphometric parameters of its species and a key to them.

Nematodes of the order Dorylaimida from Romania. The genus Thonus Thorne, 1974. Part II

AbstractFive Thonus species from Romania are described. Thonus montanus sp. n. is characterised by its body length of 1.56-1.90 mm, cuticle with coarse transverse striations, lip region 15-18 μm diam., odontostyle 20-22.5 μm long, plicate guiding ring, neck 400-553 μm long, pharyngeal expansion occupying 49-56% of total neck length, uterus 1-1.5 body diam. long, pars refringens vaginae with two separate pieces, gland cells present near vagina-vulva junction, vulva a short post-equatorial (V = 54-59) longitudinal slit, and female tail conoid (25-33 μm, c = 54-73, c′ = 0.8-1.2) with abundant blister-like structures and distinct hyaline portion. Thonus tenuistylus sp. n. is characterised by its body length of 1.17-1.56 mm, lip region offset by a more or less, usually well, marked constriction and 16-17.5 μm diam., slender odontostyle 17-20.5 μm long or 1.1-1.3 times lip region diam., neck 275-397 μm long, pharyngeal expansion occupying 42-52% of total neck length, female genital system amphidelphic, uterus bipartite and 1.7-2 body diam. long, pars refringens vaginae with two adjacent pieces, vulva a post-equatorial (V = 50-56) transverse slit, tail conoid-rounded (19-24 μm, c = 48.7-72.9, c′ = 0.8-1.0) and with abundant blister-like structures, spicules 38-43 μm long, and 3-6 widely spaced ventromedian supplements. Thonus sp. is characterised by its slender (a = 37.5) body 1.41 mm long, lip region practically continuous with adjacent body and 11.5 μm diam., odontostyle 10.5 μm long, neck 325 μm long, pharyngeal expansion 138 μm long or ca two-fifths of total neck length, a coarse ring-like structure surrounding cardia, female genital system amphidelphic, uterus ca 2.5 body diam. long, pars refringens vaginae with two adjacent trapezoidal pieces, vulva a transverse slit (V = 52), a pseudocoelomocyte present at mid-body, tail convex conoid (26.5 μm, c = 56, c′ = 1.1) with abundant blister-like structures, and males unknown. Thonus eroshenkoi n. comb. and T. medianus n. comb. are proposed. Thonus kaszabi and T. medianus n. comb. are new records for the Romanian nematode fauna.

The African Rhigonematoidea (Nematoda: Rhigonematida). 2. Six new species of Rhigonema Cobb, 1898 (Rhigonematidae)

AbstractSix new species of Rhigonema are described from the gut of various African diplopods. Rhigonema fecundum sp. n., from South Africa, is characterised by medium to fairly long body length, finely pilose anterior region, posterior margin of cephalic collar smoothly fused to body contour, Type 2 genital tract with a long ovejector, presence of a long, closely adpressed, vulval flap, tail shape in both sexes, broad spicules of medium length and complement of 23 copulatory papillae of which three pairs are subdorsal or sublateral in position. Rhigonema oxydesmi sp. n., from Oxydesmus platycercus concolor, Zaire, is characterised by medium body length, slightly projecting cephalic collar, finely pilose anterior region, Type 2 female genital tract with a long ovejector, presence of a short, adpressed, vulval flap, tail shape in both sexes, medium length spicules with a hamate capitulum and complement of 23 copulatory papillae, three pairs of which are subdorsal or sublateral in position. Rhigonema peziphorum sp. n., from Sphaerotherium selindum, Zimbabwe, is characterised by medium body length, prominently projecting cephalic collar, finely pilose anterior region, Type 1 female genital tract with a medium length ovejector, rather large eggs, absence of a prominent vulval flap, presence of a spermatophore, tail shape in both sexes, unusually short spicules with a weakly hamate capitulum and complement of 23 copulatory papillae. It is the only known Rhigonema species to form a spermatophore. Rhigonema rostrellum sp. n., from Ivory Coast, is characterised by medium body length, finely pilose anterior region, Type 2 genital tract with a very long ovejector, presence of a closely adpressed vulval flap, tail shape in both sexes, broad spicules of medium length and complement of 23 copulatory papillae of which three pairs are subdorsal or sublateral in position. Rhigonema spicatum sp. n., from Congoromus flabellatus, Zaire, is characterised by medium body length, slightly projecting cephalic collar, densely pilose anterior region, Type 2 female genital tract with a long ovejector, presence of an adpressed vulval flap, tail shape in both sexes, relatively short spicules with a hamate capitulum and complement of 23 copulatory papillae. Rhigonema xiphiurus sp. n., from Oxydesmus sicarius, Zaire, is characterised by medium body length, projecting cephalic collar, coarsely pilose anterior region with bristly microtrichs, microtrichs extending down body to beyond vulval level in female and a similar relative position in the male, Type 2 female genital tract with a long ovejector, elongate female tail, convex conoid male tail with an exceptionally well developed subulate projection, very short spicules and disposition of the 23 copulatory papillae, three pairs of which are dorsal or sublateral in position. A synopsis of the other eight nominal species of African Rhigonema is appended.

Taxonomy of Some New and Known Species of the Genus Tylencholaimellus With a Proposal for Margollus Gen. N. (Nematoda: Dorylaimida)

In this paper two new species of the genus Tylencholaimellus (T. loofi and T. cylindricus) are described and new information is provided on T. projectus Siddiqi, 1964 from Malawi and T. hispanicus Pena Santiago & Coomans, 1990 which is transferred to a new genus, Margollus, with M. bellus as type species. Tylencholaimellus loofi sp. n. is characterized by body length 0.6-0.9 mm, lip region offset by a less marked constriction, stylet 19-20.5 μm, pharyngeal bulb 22-30 μm, V = 26.6-33.5, prevulval sac 14-30 μm (0.5-1.0 times the corresponding body width), tail convex conoid to hemispherical (14-30 μm long, c = 37-55 and c' = 0.65-1.1), and males absent. T. cylindricus sp. n. can be distinguished by body 0.7-1.0 mm long, lip region continuous, stylet 25-28 μm, pharyngeal bulb 26-36 μm long, V = 28.7-36, anterior uterine sac 40-90 μm long (0.7-2.2 times body diameter), female tail hemispherical (16-20 μm long, c = 41.8-68.7, c' = 0.5-0.6) and characteristically slender spicules 44-50 μm long. Margollus gen. n. is very close to Tylencholaimellus but differs from it in having a very well developed cephalic framework with labial and postlabial sclerotization. M. bellus sp. n. is recognized by the medium sized body (0.84-0.96 mm long), lip region attenuated with its most anterior part set off by a constriction and the posterior part continuous with the body, labial sclerotization with a hook-like anterior part, stylet 30-22 μm long, pharyngeal bulb length 27-31 μm, female tail convex conoid (its length 21 μm, c = 41.3, c' =1.0), spicules 33-36 μm long and only one ventromedian supplement present.

Studies On the Genus Discolaimium Thorne, 1939 (Nematoda : Dorylaimoidea), With Descriptions of Two New Species and a Discussion On the Validity of Discolaimoides Heyns, 1963

Five species belonging to the genus Discolaimium are reported from Marathwada region, Maharashtra State, India, including descriptions of two new species. D. asji n. sp. differs from D. latum Thorne, 1939; D. sublatum Heyns, 1963; D. brachyurum Husain & Siddiqi, 1967 and D. upum Baqri & Jairajpuri, 1968 in possessing a distinct sheath covering the posterior portion of the oesophagus; and from D. obtusum Husain & Siddiqi, 1967 in the shape of tail, which is dorsally convex conoid with subacute terminus against broadly rounded in D. obtusum. D. oostenbrinki n.sp. differs from D. monhystera Siddiqi, 1965 in having a longer tail, distinct lateral organs and body cuticle composed of two layers. D. simplex Siddiqi, 1965 and D. upum Baqri & Jairajpuri, 1968 are reported. A male of D. bulbiferum (Cobb, 1906) Timm & Bhuiyan, 1963 is reported. The genus Discolaimoides Heyns, 1963 is regarded as a synonym of Discolaimium as proposed by Timm & Bhuiyan (1963).