UDC 595.132.1]591.4:591.9(477) MORPHOLOGICAL AND CHOROLOGICAL CHARACTERIZATION OF LONGIDORUS INTERMEDIUS KOZLOWSKA & SEINHORST, 1979 FIRSTLY REPORTED FROM UKRAINE WITH THE COMMENTS ON LONGIDORUS ELONGATUS (DE MAN, 1876) THORNE & SWANGER, 1936

© 2018 S.A. Susulovska et al.; Published by the Ivan Franko National University of Lviv on behalf of Біологічні Cтудії / Studia Biologica. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://www.budapestopenaccessinitiative.org/ and Creative Commons Attribution 4.0 License), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. UDC 595.132.1]591.4:591.9(477)


INTRODUCTION
The genus Longidorus Micoletzky, 1922 consists of more than 150 valid species which are ectoparasites of vascular plants inhabiting terrestrial biotopes [1]. Nine Longidorus species have been previously reported from Ukraine: Longidorus attenuatus Hooper, 1961, L. caespiticola Hooper, 1961, L. danuvii Barsi Thorne, 1939. [11,13,14]. During recent survey, four populations of Longidorus genus were identified as Longidorus intermedius Kozlovska, Seinhorst, 1979. This is the first report of L. intermedius on the territory of Ukraine. This species was described from Netherlands and Germany from the rhizosphere of Quercus robur L. [7]. It was also previously reported from Belgium, Italy, Spain, countries of Balkan Peninsula and Central Europe and from the European part of Russia [2,9,10,12]. Most populations of L. intermedius were collected in oak forests from the rhizosphere of Quercus spp. But it has also been reported on the rhyzosphere of some other plant species, for example olive Olea europea L. in Spain and from the grasses in Belgium and Poland [4,10]. Based on these data, Bulgarian nematologists concluded that this species is closely associated with oak forests and its potential distribution range may extend eastwards to the Dnipro River [10].
Longidorus elongatus is more widely distributed on the territory of Western Ukraine. It was previously detected in different types of oak and beech forests in Opillia, Subcarpathia and Carpathian mountains [6].
The objectives of this study were to determine main morphological and chorological characteristis of four populations of L. intermedius from the Western Ukraine and to describe morphological differences between L. intermedius and the most closely related and widely distributed species of L. elongatus.

MATHERIALS AND METHODS
Soil samples containing L. intermedius and L. elongatus were taken from natural and anthropogenically altered localities on the territory of Opillia and Zakar pattia in Ukraine. Localities and host-plants are presented in Table 1, 3. Nematodes were extracted from 500 cm 3 of soil by modified sieving and decanting method [3]. Extracted specimens were heat killed, fixed in triethanolamine formalin (TAF), processed to glycerol by a slow evaporation method and mounted on permanent slides. Measurements and photos were made using Olympus BX 51 microscope with Nomarski differential interference contrast, equipped with a digi tal camera Olympus DP 72 and computer program Quick PHOTO MICRO 2.3.  Table 1, 2) Female Body of a medium length -3.31-5.16 mm, assuming C-shape or open spiral when heat relaxed. The anterior body end is conical, tapering gradually. Lip region slightly offset from the rest of the body, 5-6 µm high and 11-13 µm wide, rounded, slightly flattened frontally. Amphidial pouches large, stretching to about halfway of the distance from anterior end to guiding ring, symmetrically bilobed at the base. Odontostyle, odontophore and guide ring typical for genus. Oesophagus dorylaimoid with muscular bulb equaled 105 (91-119) × 21 (17-25) µm. Oesophago-intestinal valve variable in shape, from conical to rounded. Vuvla a transverse slit situated almost equatorially, vagina 16 (13-19) µm wide and 26 (23-33) µm long occupying approximately half of the corresponding body width. Reproductive system amphidelphic, with equally developed genital branches 260 (205-314) and 240 (192-295) µm long, respectively. Prerectum of a variable length 344 (233-483) μm, rectum 29 (23-36) µm long or as long as 3/4 of anal body width. Tail dorsally convex, ventrally almost straight, bluntly conoid with a rounded terminus.

Longidorus intermedius
Male Males are very rare and morphologically similar to female, with a posterior region of body more coiled. Body length -3.31-4.22 µm. Spicules of a medium length -53.3 (51-56) µm, very slightly curved ventrally. Lateral guiding pieces 16.9 (16.8-17) µm long, almost straight with slightly bifid distal ends. Adanal pair of supplements preceded by ventromedian row of 8-10 supplements. Tail ventrally more curved than in female, bluntly conoid with a rounded terminus. Juveniles ( Table 2) The analysis of morphometrics revealed presence of only three juvenile developmental stages, same as in previous publications [2,7,9,10]. Morphologically juveniles are similar to adults. Juvenile stages can be clearly distinguished by the body length and the length of functional and replacement odontostyle. Tail length of juveniles doesn't change significantly during their development, but J1 tail is characterized by a digitate terminus.
All four Ukrainian populations of L. intermedius are very similar to each other and to previously described populations, but some differences were revealed during the analysis. In comparison to type population from the Netherlands, they have higher va-  [10]. They are more similar to Italian, Spanish and Czech populations [9,10].