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  • Author or Editor: Joaquín Abolafia x
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Two very similar species of the genus Chiloplacus, namely C. magnus and C. insularis, are re-described and compared based on type material as well as Iberian specimens. Relevant new information is obtained for their characterisation and for elucidating their identity with more accuracy. Special mention is deserved by the findings regarding: i) the morphology of the lateral field at vulval level; and ii) the location of the vulva, which is either midventral or subventral, two remarkable traits that were originally overlooked. Chiloplacus magnus is distinguished by having the left lateral field expanded at vulval level and the vulva displaced to a subventral position, whereas C. insularis displays the usual pattern of the genus. The evolutionary relationships of the Iberian C. magnus are explored by means of D2-D3 sequence analysis. Chiloplacus similis is regarded as identical to C. magnus and is proposed as a new junior synonym of the latter.

In: Nematology

The intricate taxonomical history of Aporcelinus granuliferus, the most often recorded species of its genus, is reviewed and discussed. A new concept, based on its original description, is proposed for it as type material is apparently lost although available data provide enough information to complete and update its diagnosis: 1.20-1.70 mm long body, lip region 15-16 μm broad, odontostyle 17-21 μm long, neck 309-403 μm long, pharyngeal expansion 155-214 μm long, dorsal cell mass present at pharyngo-intestinal junction, uterus simple and up to one body diam. long, V = 47-55, female tail conical with acute tip and occasionally somewhat recurved dorsad (46-55 μm; c = 24-37; c′ = 1.4-1.9), and male absent. The population studied by Thorne & Swanger () is certainly not conspecific with Cobb’s original one due to significant differences in lip region breadth and odontostyle length, and belongs to a non-described species, herein characterised and named as A. brasiliensis sp. n.: 1.5-1.6 mm long body, lip region offset by constriction and 24-27 μm wide, odontostyle 25-28 μm long, neck 345-370 μm long, V = 48, tail conical (46-55 μm; c = 29-32; c′ = 1.3-1.4) with very finely rounded or acute tip and barely recurved dorsad, spicules 54-72 μm long and nine irregularly spaced ventromedian supplements with no hiatus. The three females deposited with USDANC are not identical either to those studied by Cobb or by Thorne & Swanger, and also belong to a non-described species, herein characterised as named as A. neogranuliferus sp. n.: 1.25-1.31 mm long body, lip region offset by constriction and 17.5-18.0 μm broad, odontostyle 18 μm at its ventral side, neck 312-337 μm long, pharyngeal expansion 136-168 μm long, dorsal cell mass present at level of pharyngo-intestinal junction, uterus simple and 41-48 μm long or 0.6 times corresponding body diam., V = 49-53, female tail conical (28-35 μm; c = 36-46; c′ = 0.8-1.0) with finely rounded terminus and no hyaline region. Both Dorylaimus reynecki and D. yucatanensis, hitherto considered to be identical to A. granuliferus, are valid species, being transferred to Aporcelinus as A. reynecki comb. n. and A. yucatanensis comb. n. The available information on D. micrurus and D. menzeli lacks sufficient relevant detail to characterise these species, which are therefore regarded as species inquirendae within Aporcelinus and are transferred as A. micrurus comb. n. and A. menzeli comb. n. The true identity of other records of A. granuliferus is analysed and discussed in the light of the new concept of the taxon.

In: Nematology

Type material of Chiloplacus subtenuis and C. tenuis was studied and Iberian material originally described as C. tenuis re-examined. The results provided relevant new information to elucidate the identity of these species with more accuracy. On studying their type material, new features and details of C. subtenuis and C. tenuis were observed concerning the nature of the lip margin, morphology of the labial probolae, the lateral field at vulval level, and the orientation of the vulva (ventral or subventral). Re-examination of Iberian material of C. tenuis revealed that it consists of specimens belonging to three taxa: C. tenuis, C. membranifer, and an unknown species described and named herein as C. mysteriosus sp. n. The morphology of lip region in representatives of Chiloplacus is analysed and discussed. Zeldia spannata is transferred to Chiloplacus as C. spannatus comb. n. and Chiloplacus juniperi is regarded as a junior synonym of Nothacrobeles nanocorpus.

In: Nematology

Abstract

Five known and one new species of the genus Chiloplacus Thorne, 1937 are studied from natural ecosystems in the SE Iberian Peninsula: C.demani (Thorne, 1925) Thorne, 1937, C. maginensis sp. n., C. minimus (Thorne, 1925) Andrássy, 1959, C. magnus Rashid & Heyns, 1990, C. tenuis Rashid & Heyns, 1990 and C. trilineatus Steiner, 1940. Chiloplacus maginensis sp. n. is characterised by a female body length of 272-345 μm, lateral field starting far anterior near the labial region and with five incisures, lip region with bifurcate labial probolae bearing short prongs, pharyngeal corpus 2.5-3.6 times isthmus length, ovary without flexures posterior to vulva, spermatheca 8-17 μm long, postuterine sac 0.2-0.5 of corresponding body diam. long, female tail conical with rounded terminus (12-20 μm; c´ = 15.0-26.6; c′ = 1.1-1.5), phasmid at 39-48% of tail length. Descriptions, measurements and illustrations, including SEM photographs, are provided for the six species recorded. The diagnosis of Chiloplacus is emended, the nominal species listed and a key provided to those nominal species currently regarded as valid.

In: Nematology

Abstract

Material of the nematode previously known as Heterocephalobus elongatus (and the type of the genus) was collected in four localities from the southern Iberian Peninsula and is described and illustrated. The first SEM study of the species is presented. The species is transferred to the genus Pseudacrobeles on the basis that the lateral field fades out near the phasmid. Within this genus it is classified under the subgenus Pseudacrobeles as the lip region has a triradiate symmetry. The combination Pseudacrobeles (Pseudacrobeles) elongatus (de Man, 1880) comb. n. is proposed. As a result of synonymising the type of Heterocephalobus, the genus itself becomes a junior synonym and is herein placed under the genus Pseudacrobeles, subgenus Pseudacrobeles. The species formerly listed under Heterocephalobus are returned to their original combination and listed as species incertae sedis or species inquirendae.

In: Nematology

Type material of Acrobeloides longiuterus, consisting of three female and six male paratypes, were studied, revealing relevant new data to establish the identity of this species with more accuracy. Its detailed original description is fully confirmed although the ovary is situated in a dextral position with respect to the intestine, a remarkable feature that was not mentioned in the original description, but the same as in A. camberenensis where it was regarded as a diagnostic character. Thus, there is no longer any justification to maintain a separate status for these taxa and A. camberenensis is regarded as a junior synonym of A. longiuterus due to priority of publication.

In: Nematology

Abstract

Two new species belonging to the genus Mesodorylaimus Andrássy, 1959 are described and illustrated from natural areas in south-eastern Spain. M. nevadensis sp.n. is characterised by a medium sized body (L = 1.40-1.67 mm in females and 1.27-1.63 mm in males), angular lip region offset by a more or less marked depression, odontostyle 12.5-14.0 μ m long or 1.1-1.3 times as long as the lip region width, pharyngeal bulb 106-155 μ m long, V = 48-55, pars refringens vaginae with two divergent, triangular to dropshaped sclerotisations well separated by a more or less distinct sclerotised area, female tail relatively long and straight (93-134 μ m, c = 10.4-15.1, c′ = 4.0-5.6), spicules 41-47 μ m long, and eight to ten ventromedian supplements. M. baeticus sp.n. is distinguished by its medium sized body (L = 1.38-1.80 mm), lip region continuous or offset by a weak depression, odontostyle 13-15 μ m or 1.1-1.3 times the lip region diam., pharyngeal bulb 126-158 μ m long, V = 49-56, pars refringens vaginae with two adjacent, trapezoid to drop-shaped sclerotisations, female tail (83-126 μ m, c = 12-19, c′ = 3.7-5.6) tapering abruptly at first, then thickening very slightly and finally tapering gradually to a cylindrical terminal portion, and males unknown. These two species being quite close to M. bastiani (Bütschli, 1873) Andrássy, 1959, a compendium is presented of the relatives of M. bastiani together with a comparative discussion. M. similibastiani Zell, 1986 is regarded as junior synonym of M. bastiani. Nématodes de l'ordre des Dorylaimida d'Andalousie orientale, Espagne. Le genre Mesodorylaimus Andrássy, 1959. V. Deux nouvelles espèces proches de M. bastiani avec un compendium des espèces voisines - Deux nouvelles espèces, provenant de zones naturelles dans le sud-est de l'Espagne, appartenant au genre Mesodorylaimus Andrássy, 1959 sont décrites et illustrées. M. nevadensis sp.n. est caractérisé par un corps de taille moyenne (L = 1.40-1.67 mm chez les femelles et 1.27-1.63 mm chez les mâles), une région labiale angulaire et séparée du reste du corps par une constriction plus ou moins prononcée, un odontostyle long de 12.5-14.0 μ m ou 1.1-1.3 diam. de la région labiale, un bulbe pharyngien long de 106-155 μ m, V = 48-55, la pars refringens vaginae munie de deux sclérotisations bien séparées, divergentes, de forme triangulaire à ovoïde, une queue relativement longue et droite chez la femelle (93-134 μ m, c = 10.4-15.1, c′ = 4.0-5.6), des spicules longs de 41-47 μ m, et huit à dix suppléments ventromédians. M. baeticus sp.n. se distingue par son corps de taille moyenne (L = 1.38-1.80 mm), la région labiale continue ou séparée du reste du corps par une légère constriction, l'odontostyle long de 13-15 μ m ou 1.1-1.3 diam. de la région labiale, le bulbe pharyngien long de 126- 158 μ m, V = 49-56, la pars refringens vaginae munie de deux sclérotisations adjacentes trapézoïdales à ovoïdes, la queue de la femelle (83-126 μ m, c = 12-19, c′ = 3.7-5.6) se rétrécissant d'abord brutalement, puis s'épaississant très légèrement pour finalement se rétrécir graduellement jusqu'à une portion cylindrique terminale et l'absence mâles. Ces deux espèces sont proches de M. bastiani (Bütschli, 1873) Andrássy, 1959 et un compendium des espèces voisines de M. bastiani est donné de même qu'une discussion comparative. M. similibastiani Zell, 1986 est considéré comme synonyme mineur de M. bastiani.

In: Nematology

A Costa Rican population of the rare (infrequent) genus Makatinus was characterised on the base of LM and SEM observations. It was initially identified as belonging to M. macrostylus, a well described species that was also originally collected from Costa Rica, this representing the second record of this taxon. Nevertheless, a comparative analysis with other species of the genus revealed that M. macrostylus cannot be distinguished from M. crassiformis, an old and poorly characterised species only known to occur in Surinam and surprisingly never compared with M. macrostylus. As a result, M. macrostylus is regarded as a junior synonym of M. crassiformis and new morphological and morphometric features are provided, including those derived from SEM observations.

In: Nematology

Summary

Butlerius butleri was isolated during a survey on free-living soil nematodes from South Africa. The South African population of B. butleri is characterised by having a large stoma divided into two chambers and bearing a thorn-like dorsal tooth, spicules 44 (41-49) μm long, gubernaculum 29 (28-30) μm long, three pairs of precloacal papillae and five pairs of postcloacal papillae, and a filiform tail 280 (204-332) μm long in females, 310 (256-356) μm long in males. The SEM observation showed the cheilostom is divided into six conical plates 2.1-2.3 μm long. Nblast of 18S rDNA revealed 99% similarity and 6-7 bp differences with the B. butleri (KP453998) from Iran. Molecular analysis of B. butleri based on the sequence of the 18S and 28S rDNA placed it together with Butlerius and close to Pseudodiplogasteroides and Diplogasteroides. This species showed predatory and cannibalistic behaviours, feeding on other B. butleri in the substrate. SEM photographs of the species are presented for the first time.

In: Nematology