Experimental induction of intraspecific morphometric variability in a single population of Halicephalobus cf. gingivalis may surpass total interspecific variability

Nematology ◽  
2013 ◽  
Vol 15 (5) ◽  
pp. 529-544 ◽  
Author(s):  
Pamela Fonderie ◽  
Hanne Steel ◽  
Tom Moens ◽  
Wim Bert
Keyword(s):  
New Species ◽  
Univariate Analysis ◽  
Age Groups ◽  
Tail Length ◽  
Nematode Species ◽  
Molecular Techniques ◽  
Morphological Data ◽  
Morphometric Study ◽  
Morphometric Characters ◽  
Adult Age

Although molecular techniques are revolutionising nematode taxonomy, morphological data still form the basis of nematode species descriptions. However, morphological characters show a natural variability that should be taken into account before describing new species. The current study presents the results of an elaborate morphometric study of Halicephalobus cf. gingivalis, including 15 measurements and 13 indices of 540 specimens, the progeny of a single parthenogenetic female and cultured under different temperature and food conditions and measured in different adult age groups, i.e., young adults with a developed vulva but before the onset of oviposition, adults laying eggs, and old, post-reproductive adults near the end of their life cycle. The morphometric characters were analysed using both univariate (analysis of variance) and multivariate (principal components and canonical discriminant analysis) techniques. The main results reveal that the morphometric characters most used in Halicephalobus identification keys have a huge variability within a single progeny, e.g., body length 1.9 times longer than the shortest or ratio VA/tail length 3.9 times larger than the smallest. This variability has a magnitude that has not been observed in nematodes before. Further, by changing the environmental factors, the morphometric characters are influenced to an extent that one could assign – with seemingly ‘statistical support’ – different ‘species’ of the genus to different subpopulations. With this experimental study we provide convincing elements to advocate an integrative taxonomic approach and to discourage the description of new species based only on morphometric differences.

Steinernema innovationi n. sp. (Panagrolaimomorpha: Steinernematidae), a new entomopathogenic nematode species from South Africa

2014 ◽  
Vol 89 (4) ◽  
pp. 415-427 ◽  
Author(s):  
H. Çimen ◽  
M.-M. Lee ◽  
J. Hatting ◽  
S. Hazir ◽  
S.P. Stock
Keyword(s):  
South Africa ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
Mitochondrial Gene ◽  
Tail Length ◽  
Nematode Species ◽  
Total Body Length ◽  
Morphological Data ◽  
Cross Hybridization ◽  
Molecular Sequence Data

AbstractMorphological and molecular sequence data were combined with cross-hybridization studies and used to identify a new Steinernema sp. from Free State, South Africa. Molecular and morphological data indicate that the new species belongs to the ‘glaseri-group’ of Steinernema spp. Key morphological diagnostic characters for S. innovationi n. sp. include the morphometric features of the third-stage infective juveniles: total body length = 1054 (1000–1103) μm, tail length = 108 (97–117) μm, location of the excretory pore = 88 (82–91) μm, and D% = 58 (54–63), E% = 115 (104–137) and H% = 43 (37–46). Additionally, the morphology of the spicules and gubernaculum of the first-generation males are considered key diagnostic traits. Steinernema innovationi n. sp. was also characterized by analysis of both rDNA and mitochondrial gene sequence data, which further indicate the uniqueness of this Steinernema species.

Prodorylaimus filamentus sp. n. and Eutobrilus longicaudatoides sp. n. (Nematoda) from Lake Baikal, Russia

Zootaxa ◽  
2011 ◽  
Vol 3103 (1) ◽  
pp. 57 ◽  
Author(s):  
VLADIMIR G. GAGARIN ◽  
TATYANA V. NAUMOVA
Keyword(s):  
New Species ◽  
Lake Baikal ◽  
Tail Length ◽  
Nematode Species ◽  
Length Ratio

Two nematode species found in Lake Baikal, Russia are described. Prodorylaimus filamentus sp. n. is morphologically close to P. longicaudatoides Altherr, 1968 and P. kralli Tsalolikhin, 1975. The new species can be separated from P. longicaudatoides by the longer body (L = 4.89–6.06 mm versus L = 2.0–3.5 mm), relatively longer tail (c′ = 18.4–25.0 versus c′ = 14–18), longer odontostyle (60–65 µm long versus 32–37 µm long), presence of double and wide guiding ring and longer spicules (89–90 µm long versus 70–78 µm long). It can also be separated from P. kralli by the longer tail (c = 4.3– 6.0, c’ = 18.4–25.0 versus c = 7.0–8.0, c′ = 11–16), lower “vulva-anus to tail length” ratio (1.6–2.2 versus 2.5–3.0), shorter odontostyle (60–65 µm long versus 75–80 µm long). Eutobrilus longicaudatoides sp. n. is closely related to E. anguiculus Tsalolikhin, 1977, but is clearly distinct in the shorter outer labial setae (9–10 µm long or 45–52% of the labial region diameter versus 15–20 µm long or 50–60 % of the labial region diameter), longer tail (males, c = 5.3–5.5, c’ = 11.4–11.8, females, c = 4.5–6.3, c′ = 15.1–16.7, versus males, c = 7.4–10.4, c′ = 8–9, females, c = 5.0–7.7, c′ = 10–12), smaller number of supplements (5 versus 6) and shorter spicules (47–53 µm long versus 66–68 µm long).

Steinernema vulcanicum n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode species from Sicily (Italy)

Nematology ◽  
2011 ◽  
Vol 13 (4) ◽  
pp. 409-423 ◽  
Author(s):  
Eustachio Tarasco ◽  
Mirella Clausi ◽  
Giancarlo Rappazzo ◽  
Maria Teresa Vinciguerra ◽  
Agata Longo
Keyword(s):  
New Species ◽  
Dna Sequences ◽  
Entomopathogenic Nematode ◽  
Posterior Part ◽  
Morphological Characteristics ◽  
Nematode Species ◽  
Mount Etna ◽  
Morphological Data ◽  
Field Pattern ◽  
Lateral Field

AbstractA new species of entomopathogenic nematode, Steinernema vulcanicum n. sp., is described from the slopes of Mount Etna (Sicily, Italy). It was recovered from soil in a chestnut wood. Molecular and morphological data indicate that the new species belongs to the glaseri group of Steinernema spp. The new species can be distinguished from the other described species of the group by morphological characteristics, crossbreeding tests and by the DNA sequences of ITS1 rDNA, 12S and cox1 mitochondrial loci. Steinernema vulcanicum n. sp. is characterised by the long and slender male spicules, with manubrium wider than long, velum prominent, rounded tip with ventral concavity and tail without mucro. The female has double epiptygmata in both generations. The third-stage infective juveniles have an average body length of 1200 μm, excretory pore generally located level with posterior part of the pharyngeal corpus (D% = 47-68), lateral field pattern of variable formula and hyaline part of tail forming ca 50% of its length. The DNA sequences, life cycle and the endosymbiotic bacterium of S. vulcanicum n. sp., Xenorhabdus kozodoii, indicate the similarity of the new species with S. arenarium, S. apuliae and S. boemarei, from which it can be distinguished by both morphological and molecular characters.

Heterorhabditis floridensis n. sp. (Rhabditida: Heterorhabditidae) from Florida

Zootaxa ◽  
2006 ◽  
Vol 1177 (1) ◽  
pp. 1 ◽  
Author(s):  
KHUONG B. NGUYEN ◽  
UGUR GOZEL ◽  
HEATHER S. K_PPENH_FER ◽  
BYRON J. ADAMS
Keyword(s):  
New Species ◽  
Entomopathogenic Nematodes ◽  
Tail Length ◽  
Nematode Species ◽  
Terminal Group ◽  
The Other ◽  
Citrus Groves ◽  
Molecular Studies ◽  
Its Regions ◽  
A New Species

In a survey of entomopathogenic nematodes associated with plants and trees in areas adjacent to production citrus groves in Florida, a new species of nematode in the genus Heterorhabditis was found based of morphological and molecular studies. The new nematode is described as Heterorhabditis floridensis n. sp. H. floridensis n. sp. is characterized by males, females, and infective juveniles. For males, the number of papillae in the terminal group of bursa is variable, either with 2 pairs of papillae (40%), with 3 papillae on one side and 2 papillae on the other side (30%), with one pair of papillae (20%), or with three pairs of papillae (10%). SW and GS values are 179 and 50, respectively. Females have a typical vulva pattern, which is different from that of closely related nematode species H. bacteriophora, H. mexicana, and H. indica. For infective juveniles, EP=109 (101–122) µ m, ES=135 (123–142) µ m, tail length=103 (91–113) µ m, and a=27.6 (25–32) are different from those of the above-mentioned three related nematodes. Phylogenetic analysis based on ITS regions show that the new species forms a clade with H. mexicana, H. baujardi and H. indica and differs from these species by several nucleotide autapomorphies.

Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae): the hidden host of Photorhabdus asymbiotica (Enterobacteriaceae: γ-Proteobacteria)

2009 ◽  
Vol 83 (4) ◽  
pp. 309-320 ◽  
Author(s):  
K.L. Plichta ◽  
S.A. Joyce ◽  
D. Clarke ◽  
N. Waterfield ◽  
S.P. Stock
Keyword(s):  
New Species ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Its Region ◽  
Nematode Species ◽  
Diagnostic Features ◽  
Cross Hybridization ◽  
Group V ◽  
Terminal Set

AbstractA new entomopathogenic nematode species from Australia, Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae) is described. Morphological and molecular studies together with cross-hybridization tests indicated that this nematode represents a new undescribed species, closely related to members in the ‘indica-group’. However, the new species can be distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. Key diagnostic features include: body size and excretory pore position of the third-stage infective juveniles; male bursa with a reduction of bursal rays, usually affecting the terminal set of papillae, with symmetrical or asymmetrical loss of one or two pairs; vulva of hermaphrodites more anteriorly located than in other species in the indica-group (V% average: 43), with non-protruding or slightly protruding lips, and longer tail length (average: 106 μm). The new species can be further characterized by molecular traits of sequence data from the internal transcribed spacer (ITS) region of ribosomal DNA. Additionally, the bacterial symbiont of this new species, Photorhabdus asymbiotica Kingscliff strain, was phenotypically characterized and compared with other P. asymbiotica strains. The Kingscliff strain revealed many characters not present in other strains of this species. We hypothesize that the newly found traits may contribute to the maintenance of this mutualistic association of the bacterium with its nematode host.

Radopholus arabocoffeae sp. n. (Nematoda: Pratylenchidae), a nematode pathogenic to Coffea arabica in Vietnam, and additional data on R. duriophilus

Nematology ◽  
2004 ◽  
Vol 6 (5) ◽  
pp. 681-693 ◽  
Author(s):  
Gerrit Karssen ◽  
Sergei Subbotin ◽  
Lieven Waeyenberge ◽  
Chau Nguyen ◽  
Maurice Moens ◽  
...  
Keyword(s):  
New Species ◽  
Coffea Arabica ◽  
Sequence Divergence ◽  
Tail Length ◽  
Nematode Species ◽  
Reproductive Capacity ◽  
Whole Body ◽  
Lateral Field ◽  
Spicule Length ◽  
Lateral Lines

AbstractRadopholus arabocoffeae sp. n., a new nematode pathogenic on Coffea arabica cv. Catimor, is described from Vietnam. Females of R. arabocoffeae sp. n. are characterised by the broad amphidial apertures with prominent margins. Males are characterised by the bursa extending to one third, rarely middle, of the tail. The new species belongs to the group of species with a long tail in the female. Radopholus arabocoffeae sp. n. is easily distinguished from R. similis by the bursa reaching to only one third of the tail vs extending to the tail terminus. Radopholus arabocoffeae sp. n. is differentiated from R. bridgei by the lateral field having three bands of equal width (vs middle one narrower than others), lateral field completely areolated over whole body vs not areolated except irregularly in neck and tail, hemizonid distinct vs indistinct, four lateral field incisures terminating far behind phasmid vs three incisures terminating at or just behind phasmid, lateral lines fusing at two thirds of tail vs fusing at one third of tail, longer spicule length (18-21 vs 15.5-18.0 μm), and male bursa usually extending to only one third of tail vs mid tail. Radopholus arabocoffeae sp. n. differs from R. colbrani by the rod-like vs round sperm, spicule length (18-21 vs 13-16 μm), tail length to stylet ratio (4.1-4.9 vs more than 5.1) and presence vs absence of a bursa. Radopholus arabocoffeae sp. n. differs from R. duriophilus by the rod-like vs kidney-shaped sperm. Males further differ from R. duriophilus by shorter stylet length (8.2-11.6 vs 11.5-15 μm), smaller distance between dorsal pharyngeal gland orifice and stylet base (1.7-3.4 vs 4-9.5 μm), shorter hyaline tail (2.6-3.4 vs 4-9.5 μm), and bursa extending to one third of tail vs mid-tail. Female R. arabocoffeae sp. n. differ from R. duriophilus by the broad amphidial aperture with prominent margin present vs absent. Males of R. arabocoffeae sp. n. differ from R. musicola by the rudimentary and amalgamated stylet base (vs with knobs), and inner lateral lines fusing at two thirds of the tail vs just posterior to the phasmid. The high level of ITS-rDNA sequence divergence of R. arabocoffeae sp. n. from other Radopholus spp. and the presence of nucleotide autapomorphies support a separate specific status of this new species. On carrot disks, the two species reproduced from 15-30°C; optimum reproduction occurring at 28°C. The reproductive capacity of R. duriophilus was higher than that of R. arabocoffeae sp. n. Radopholus duriophilus reproduced from single juveniles; R. arabocoffeae sp. n. did not. The correlation between initial densities of Pratylenchus coffeae, R. duriophilus and R. arabocoffeae sp. n. and the weight of C. arabica cv. Catimor fitted the Seinhorst model Y = ym for Pi ≥ T, and Y = ym ˙ m + ym(1–m)z(Pi–T). Coffea arabica cv. Catimor was very susceptible for to all three nematode species tested, but especially so to R. arabocoffeae sp. n. The reproductive capacity of R. arabocoffeae sp. n. on C. arabica cv. Catimor was higher than P. coffeae or R. duriophilus.

scholarly journals Short Communication: Sexual dimorphism of Hill Blue Flycatcher (Cyornis banyumas) in Hill Evergreen Forest, Mae Sa-Kog Ma Biosphere Reserve, Chiang Mai Province, Thailand

2019 ◽  
Vol 20 (6) ◽  
Author(s):  
PAANWARIS PAANSRI ◽  
SUPALAK SIRI ◽  
YUWADEE PONPITHUK ◽  
WARONG SUKSAVATE ◽  
MONGKOL SAFOOWONG ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Univariate Analysis ◽  
Biosphere Reserve ◽  
Morphological Data ◽  
Evergreen Forest ◽  
Chiang Mai ◽  
Morphometric Traits ◽  
Morphometric Characters ◽  
Sexual Discrimination ◽  
Chiang Mai Province

Abstract. Paansri P, Siri S, Ponpithuk Y, Suksavate W, Safoowong M, Nuipakdee W, Duengkae P. 2019. Sexual dimorphism of Hill Blue Flycatcher (Cyornis banyumas) in Hill Evergreen Forest, Mae Sa-Kog Ma Biosphere Reserve, Chiang Mai Province, Thailand. Biodiversitas 20: 1544-1548. A sample consisting of 60 males and 39 females Cyornis banyumas captured in the Mae Sa-Kog Ma Biosphere Reserve was examined using 42 morphometric characters to assess sexual dimorphism. The results of the univariate analysis showed that there were ten morphometric traits (Ltail, TLF, C-middle, HB, C-outer, T-inner, C-digit, T-middle, DUTET and LG) that could be used for discrimination of sexual differences. The morphological data based on significant differences revealed that males were larger than females. The results of discriminant analysis based on the significant differences of nine raw morphometric data can be used to construct a sexual discrimination equation (D) where D = -22.051 + 0.368 (Ltail). The sexual discrimination equation can be directly used to identify both sexes with 79.6% of cross-validated grouped cases correctly classified, since positive D scores indicated males and negative D scores indicated females, with 81.4% of the males and 74.4% of the females being correctly assigned with a cutoff value between sexes = 0.

Description of Bursaphelenchus taphrorychi sp. n. (Nematoda: Parasitaphelenchidae), the second Bursaphelenchus species from larval galleries of the beech bark beetle, Taphrorychus bicolor (Herbst.) (Coleoptera: Curculionidae: Scolytinae), in European beech, Fagus sylvatica L.

Nematology ◽  
2017 ◽  
Vol 19 (10) ◽  
pp. 1217-1235 ◽  
Author(s):  
Marek Tomalak ◽  
Tadeusz Malewski ◽  
Jianfeng Gu ◽  
Zhan Fa-Qiang
Keyword(s):  
New Species ◽  
Fagus Sylvatica ◽  
Bark Beetle ◽  
Tail Length ◽  
Its Region ◽  
European Beech ◽  
The Body ◽  
Molecular Profile ◽  
Morphometric Characters ◽  
Taphrorychus Bicolor

Bursaphelenchus taphrorychi sp. n. is described from the bark of European beech, Fagus sylvatica. All propagative stages of the nematode are numerous in larval galleries of the beech bark beetle, Taphrorychus bicolor, while dauer juveniles are transmitted to new breeding trees under the elytra of adult beetles. The new species is characterised by the body length of 782 (717-858) μm in female and 638 (475-789) μm in male, moderately slender body (a = 35.0 (31.7-36.5) and 35.5 (31.4-37.1) in female and male, respectively), spicules 12.0-16.0 μm long, lateral fields with four incisures (i.e., three bands), and the arrangement of the seven male caudal papillae (i.e., a single precloacal ventromedian papilla (P1), one pair of adcloacal ventrosublateral papillae (P2), one postcloacal pair (P3) located at ca 60% of the tail length, posterior to the cloacal aperture, and one pair (P4) of subventral papillae of a similar size as the previous pair, but with somewhat sunken tips, located near base of bursa). In the number and arrangement of caudal papillae, stout and curved spicules with prominent rostrum and condylus, small vulval flap, body narrowed posterior to vulva, four incisures in the lateral fields, and long post-uterine sac, B. taphrorychi sp. n. shares most of the key morphological characters with members of the sexdentati-group. However, the newly described species is unique amongst Bursaphelenchus species of this group by the combination of shape of female tail, shape of spicules, and some other morphometric characters. The close relation of B. taphrorychi sp. n. with members of the sexdentati-group has been confirmed by DNA sequencing and phylogenetic analysis of the 28S rDNA region. The taxonomic separation of the new species is also confirmed by the unique molecular profile of the ITS region (ITS-RFLP). In laboratory rearing, B. taphrorychi sp. n. can develop and reproduce on Botrytis cinerea cultures.

A new Cosmocercoides species (Nematoda: Cosmocercidae), C. tonkinensis n. sp., in the scale-bellied tree lizard (Acanthosaura lepidogaster) from Vietnam

2015 ◽  
Vol 60 (3) ◽  
Author(s):  
Binh Thi Tran ◽  
Hiroshi Sato ◽  
Pham Van Luc
Keyword(s):  
New Species ◽  
North America ◽  
Ribosomal Rna ◽  
Tail Length ◽  
Nematode Species ◽  
Land Snails ◽  
Phylogenetic Position ◽  
Molecular Phylogenetic ◽  
Tree Lizard ◽  
Toad Bufo

AbstractA new cosmocercid nematode species, Cosmocercoides tonkinensis n. sp., is described from the scale-bellied tree lizard (Acanthosaura lepidogaster) in the northern and central parts of Vietnam. The new species is characterized by medium-sized male worms (4.2-5.1 mm in length and 0.34-0.37 mm in width) relative to known members of the genus, with lateral alae, two sharply pointed spicules of equal length (0.22-0.26 mm in length), a gubernaculum (0.113-0.122 mm in length), 16 or 17 pairs of caudal rosettes, and the presence of somatic papillae. Female worms are slightly larger than male worms (5.3-5.5 mm in length and 0.32-0.42 mm in width), with the vulva situated at 3/5 from the anterior end, and elliptical embryonated eggs, 0.064- 0.084 mm long by 0.040-0.048 mm wide. From 19 recorded species of the genus, the morphology of C. tonkinensis n. sp. is closest to C. multipapillata, C. bufonis, and C. pulcher reported from toads and frogs in East Asia. The present new species is differentiated from them by the number of caudal rosettes, tail length relative to body length, presence of somatic papillae and lateral alae, and embryonated eggs. Furthermore, after C. variabilis in North America and C. sauria in Brazil, this new species is only the third species to be recorded from a reptilian host. The 18S ribosomal RNA gene (rDNA) of the new species is almost identical to that of C. dukae infecting land snails and slugs in North America. Between the present new species and C. pulcher from a toad (Bufo japonicus) in Japan, remarkably fewer nucleotide changes were noticed in the 18S to 28S rDNA including the internal transcribed spacer regions. The molecular phylogenetic position of the genus Cosmocercoides is briefly discussed.

Size-At-Age Variability and Sexual Dimorphism of Morphometric Characteristics in the Late Ontogenesis of the Marsh Frog, Pelophylax Ridibundus (Anura, Ranidae), from Terrytory of Crimea

2019 ◽  
Vol 53 (4) ◽  
pp. 325-334
Author(s):  
V. N. Peskov ◽  
N. A. Petrenko ◽  
V. Yu. Reminnyi
Keyword(s):  
Age Groups ◽  
The Body ◽  
Adult Males ◽  
Morphometric Characteristics ◽  
Morphometric Characters ◽  
Mean Values ◽  
Marsh Frog ◽  
Males And Females ◽  
Size At Age ◽  
Linear Body

Abstract We study size-at-age and sexual variability of morphometric characteristics of the marsh frog. According to the size of the body, males were divided into three size-age groups (juvenis, subadultus, adultus), females — into four groups (juvenis, subadultus, adultus, adultus-I). We found that the chronological age of frogs (skeletochronology) does not always correspond to their biological age (size and proportions of the body). We noted that the semi-adult males are reliably larger than females by mean values of 26 studied morphometric characters. Males and females of “adultus” group do not differ by linear body size, significant differences were found in body proportions (7 characters). For the females of “adultus-I” group, the mean values of 26 characters are significantly larger than for “adultus” males. The results of our study showed that with the age of the marsh frog, the level of exhibition, directionality and structure of morphometric sex differences changes.

Sign in / Sign up

Export Citation Format

Share Document