Russian Journal of Nematology, 1993, 1 (2). 74 - 95

Phylogeny of the order (Nematoda)

Alexander Yu. Ryss

Zoological Institute of Russian Academy of Sciences, Universitetskaya embankment, I, Sankt-Petersburg, 199034, Russia.

Accepted for publication 30 November 1992

Summary. The structures of the most value for the macrotaxorlomy of the class Nematoda - amphid, phasmid. deirid, lateral field and head sensory organs are situated on the lateral radii of the body or near them. It is proposed to consider all these organs as a complex structural unit: athe lateral complex*. Caudal alaeof males (bursa) also belong to the lateral complex. There are I) thenon-phasmidial caudal alae (phasmids are absent from the tail). 2) the pre-phasmidial caudal alae (caudal alae are situated anterior to the phasmids, 3) the phasmidial caudal alae (phasmids are situated on the caudal alae as phasmidial ribs, alae envelop the tail). Phylogeny of the order Tylenchida is analysed by comparison of the lateral complexes of the taxa. Atctylcrtchus is the most primitive taxon. Some amendments are made to the classificatioli by Siddiqi (1 986), which is considered closest to the riatural order. The order Tylenchida consists of 4 suborders, three of them (Tylenchina, Crico~iematina,Hexatylina) possess complexes of synapomorphic characters and therefore are considered to be monophyletic. The suborder Hoplolaimina is regarded as being paraphyletic, thuscontaining the remainder of the taxonomic divisions of the order. Hoplolaimina contains 2 superfamilies: I) Dolichodoroidea: Psilenchidae, Meiodoridae n. rank: Meiodorus, Uracllydor~ts, Ncodolichodorus, Hirsclimanniclla and 2) Hoplolaimoidea: Merli~iiidaen.rank, including Pratyletrcl~oid~s,Beloliolairnidae, (correspo~idiiigto Belonolaiminae sc'nsu Siddiqi, 1986). Tylenchorhynchidae and other families of higher plant parasites. Hoplolaimoidea differs from Dolichodoroidea by the structure of the phasrnidial caudal alae of males which envelops the tail, and by a lateral field in females and juveniles reaching the hyaline portion of the tail (in Dolichodoroidea the lateral field does not reach the hyalirie portion of the tail). Psilenchidae represent a paraphyletic group which is not defined by synapomorphic characters. The most primitive taxa of Tylenchida. including Atctylcr~cl~us,belong to this group. Keys for the identificatioli of the superfamilies and the families of the suborder Hoplolaimina are given. Key-words: phylogeny, morphology, evolutioti, new taxa, Merlinnidae 11. rank, Meiodoridae 11. rank.

The order Tylenchida includes free-living plant was theauthor of the first phylogenetic concept for the feeding and mycophagous , specialized class Nematoda as a whole. He argued the Rhabditid- plant parasites and arthropod parasites with Diplogasterid ancestry of the Tylenchida in the complicated life cycles with an alternation of modern context (Filipjev, 1934). This point of view was parthenogenetic and gamogenetic generations. The developed by Paramonov ( 1962, 1970) who proposed aim of this paper is an analysis of phylogenetic the hypothesis of the origin of the higher relations in the order, using a new approach. The phytoparasitic tylenchids and of the whole order from author proposes some changes in the order primitive fungus feeders. The most important among classification on the basis of this analysis. the more recent phylogenetic papers are: the Many nematologists investigated the phylogeny fundamental monograph by Siddiqi (1986), the joint as well as the classification of the order (Chitwood & set of articles by Fortuner, Maggenti, Luc, Geraertand Chitwood, 1950; Maggenti, 1971, 198 1; Andrassy, Raski <(A reappraisal of Tylenchina,> which was later 1976; Skarbilovich, 1978, 1980; Sumenkova, 1984; published as a separate volume (Fortuner et al., 1987- Drozdovsky, 1989). A prominent contribution to the 1988) as well as the series of articles by Chizhov and phylogenetic study was made by Filipjev (1934), who co-authors (Chizhov & Berezina, 1988; Chizhov & Kruchina, 1988, 1992). In general these recent of an analysis of the diversity of the lateral complex it phylogenetic papers consider Tylenchida separately is possible to define: I) the most primitive taxon of the from the general evolution of Nematoda. For this Tylenchida by comparison with the lateral complexes reason the choice of the main characters and of closely related orders; 2) the transformations of the evolutionary directions in the transformation series of initial lateral complex within the order; 3) how the these characters depend mainly on the point of view of lateral complex transformations are in concordance each author and not on detailed comparison of the with alternations in other characters and present a taxon with all possible uout-liersa. Such a comparison general view of the evolution in the order on the basis should define the choice of the most significant char- of these data. The classification by Siddiqi (1986) is acters. Usually on the basis of the chosen characters used as the basic one for this analysis as it appears to the sums of the plesiomorphies and synapomorphies be closest to the natural order and uses the greatest are calculated. Thereafter the phylogenetic diagram number of taxonomic characters. The family with dichotomous branching is constructed, using Myenchidae (parasites of the leech coelom) and the these calculations. family Myoryctesidae (parasites of amphibian muscles) were excluded from the examination as little The proposed approach. In this article the information is available on their morphology, Tylenchida is examined from general nematological especially on the structure of the lateral complex. taxonomic principles, as Filipjev did, but with much new knowledge of this group. The most important Review of lateral complex characters for Nematoda macrosystematics are structures situated on 2 lateral radii of a threadlike body. They are: an amphid (a paired cephalic chemoreceptor), a Peristomal complex of sensilla and the phasmid, peristomal cephalic sensilla, a lateral field subdivision of the anterior body end. The stomata1 and a cervical papilla (a deirid). The basis of this line opening with a complex of surrounding sensilla are is the lateral field - a paired surface structure of two located at the junction of the lateral radii of a body. As lateral hypodermic chords (Fig. I. A). These chords in other Nematoda, the first circle of the inner labial are extremely important structures for a basic plan of sensilla includes 6 pore-like structures; the second and the nematode anatomy. They are of particular the third circles of sensilla are also located on the head importance in a functional sense: nematode movement region, the sensilla of the third circle (cephalic proceeds by snakelike undulation in the dorso-ventral sensilla) being situated more laterally than the second planeand the lateral chords act as flexible columns for circle sensilla (outer lip sensilla) (Fig. 1. G); for the tubular nematode body. They support the ventral examples in Pratylenchus sensillulus (Anderson & and dorsal pairs of muscle fields, which are Townshend, 1985); Radopholus similis (Baldwin et antagonistic. The undulation proceeds owing to the al., 1983). Two lateral sensilla of the second circle, antagonism of these paired sets of muscles. Also there which are usually present in other Nematoda, are not are ventral and dorsal hypodermic chords. However in detected in Tylenchida. Therefore, the general tylenchids the ventral and dorsal chords are formula for the arrangement of the anterior end significantly less developed then the lateral cords, sensilla in Tylenchida is 6 + (4 submedian + 4 similarly in and Chromadoria. The new submedian), this being a full set of sensilla. A approach here is to investigate the diversity of reduction in number of sensilla, a shift of inner labial structure of the lateral complex in the order sensilla (the lateral pair only or all of them) into a Tylenchida. The lateral complex here is regarded as a prestoma, and other transformations take place in complicated structural unit and not a sum of separate different groups. characters. This approach avoids calculations of sums It is necessary to compare the terminology used of synapomorphies and plesiomorphies. On the basis for the lip region in Tylenchida with that used for the Phylogeny of Tylenchida

dei ilp am. ISZ

m dch

Fig. 1. Morphology of the nematodes of the order Tylenchida.

A: Arrangement of structures of the lateral complex on the nematode body; 8: Transverse sectio~iof the body with the lateral chords and the bands (ridges) of a lateral field indicated; C-E: Types of male caudal alae (bursa): C - Pre-phasmidial adanal, D - Phasmidial, E - Non-phasmidial adanal; F.G:- Cephalic region: F - Lateral view, G - Face view. The corresponding projectionsare indicated by the dotted line. H: Diagram of vectors of forces in the cephalic regions of nematodes of the families and Belonolaimidae when the protractor muscles contract. For explanations see text. am - amphid, bpf - basal plate of inner cephalic framework, dch - dorsal chord, dei - deirid, cb - cephalic base, cf - cephalic framework, cp - cephalic papillae, cp + olp - cephalic papillae and outer labial papillae, ep - ekcretory pore, ilp - inner labial papillae, Ich - lateral chords, If - lateral field. Ifb - bands (ridges) of the lateral field. Isz - labial sensory zorre, m - muscle layer, olp -outer labial papillae, p - papillae of cephalic part, ph - phasmid, sto - stomatal opening, vch - ventral chord, ve - vestibulum extension, vu - vulva. non-Tylenchid Nematoda. The <>.If the bursa does slit-like, stretching longitudinally, ventrally curved, not enclose the tail tip, it is named adanal. If the situated near the cephalic baseas in Atetylenchus. This phasmid is present in the tail, the bursal ala terminates latter form occurs frequently also within the family anterior to the former. This type of a bursa is here Tylenchidae. referred to as <> (Figs. 1. C & 2). If the phasmids are absent in the tail, Lateral field. As mentioned, a lateral field is a the adanal bursa is referred to as <>(Figs. I. E & 2). presence and structure of a lateral field and its subdivision into longitudinal bands are the important The ancestral form of the order characters for the macrotaxonomy of Nematoda. For Tylenchida example Enoplia are devoid of a lateral field whereas it is present in ~ecernenteaand Chromadoria possess Not only T.ylenchida but also other orders of the it. subclass Secernentea possess all of the previously mentioned structures of the lateral complex: amphid, Deirid (cervical papilla) is present in the lateral phasmid, deirid, lateral field and a complete set of field. It is typical for Secernentea and also occurs cephalic sensilla. Themost primitive form of thelateral within the family Plectidae (subclass Chromadoria: complex in Tylenchida (= the ancestral form) can be order Chromadorida: suborder Leptolaimina, after the determined by examination of those genera with the classification by Lorenzen ( 198 1) . fullest set of the lateral complex. There are only a few genera with the complete set of the lateral complex Phasrnidsituated in the lateral field, usually in the structures: Atclylenchus, Psibnchus, Antarctenus, tail, and is a significant character for the diagnosis of Pratylenchoides and the genera belonging to the Secernentea (also referred to as the phasmidians, subfamily Merliniinae: Merlinius, Amplimerlinius, Phasmidia). Phasmid-like structures are present in Hexadorus, Nagelus, Geocenamus (Fig. 2). After the the tail within the family Teratocephalidae, belonging comparative anatomical research of Lorenzen (198 I), to the same suborder Leptolaimina. In the suborders the most primitive form of the amphid of the Phylogeny of Tylenchida

"d

Criconematina

HOPLOLAININA

f

Psilenchus

Meiodoridae n. rank.

Belonolaimidae

Hoplolaimoidea (part.)

HOPLOLAIMOIDEA

Fig. 2. Primary lateral complexes of the nematodes of the order Tylenchida.

The original lateral complexes, for the corresponding taxa are illustrated. The directions of evolution are indicated by arrows. The diversity of lateral complexes of the suborder Hoplolaimina, consisting of 2 superfamilies - Hoplolaimoidea and Dolichodoroidea (inside the rectangular contours) are illustrated in detail. The heavy arrows indicate the positions of the dorsal (dors.) and ventral (ventr.) sides of the nematode body. adanal pre-phasm. ca - adanal pre-phasmidial caudal alae. adanal termin. pre-phasm. ca - adanal terminal pre-phasmidial caudal alae, am - amphid, ca - caudal alae (bursa), cb- cephalic basis, cp+ olp -cephalic pnpillaeand outer labial papillae, dei - deirid, ilp - inner labial papillae, If - lateral field. Isz - labial sensory zone, non-phasm. ca - non-phasmidial caudal alae, ph - phnsmid, phl - phasmid-like structure. phasmidial ca - phasmidial caudal alae, phr - phasmidial rib, sto - stoma1 opening. A-A

0 -18 dors. vent. t-

J

Fig. 3. Diversity of oesophageal gland structure in the nematodes of the order Tylenchida. A-D: Lateral view; E-G:Transverse section A-A in the anterior part of the glandular body; H-J: Transversal section B-B in the posterior part of the glandular body (levels of sections A-A and B-B are marked in Figures 1-3 by lines with perpendicular arrows). A, E. H: The tylenchoid oesophagus; B. C: The lobed "hoplolaimoid" oesophagus - subventral glands are posterior to the dorsal one; B, F, I: The lobed "hoplolaimoid" oesophagus with an arrangement of the oesophageal-intestinal junction between primary subventral glands (the symmetrical type); C. G, J: The lobed *hoplolairnoid* oesophagus with an arrangement of the oesophageal-intestinal junction betwecrl the primary dorsal gland and one of the subventral glands (the asymmetrical type); D: The lobed oesophagus of the family Belonolaimidae and the subfamily Telotylenchinae of the family Tylenchorhynchidae: the dorsal gland is posterior to the subventral ones. The positions of the dorsal side of the body (dors.) and the ventral one (ventr.) are marked by heavy lines. ca - cardia, d - dorsal gland, dn - dorsal gland nucleus, in - intestine, oij - oesophageal-intestinal junction, ol - oesophageal lumen, sv - subventral gland, svn - subveritral gland nucleus.

secernentes is considered to be a slit-like, ventrally the other genera the amphid is positioned in the labial curved, postlabial amphid. This amphidial shape is sensory zone. Therefore Alelylenchus and Psibnchus primitive also for the subclass Chromadoria, and is may be considered as representing the most primitive considered to be the most primitive form for the whole form in the order Tylenchida. The amphid is wide class of Nematoda (Lorenzen, 1981). Therefore it is funnel-shaped in Psilenchus and slit-like, stretched logical also to consider that this amphidial shape is the longitudinally, ventrally curved in Alelylenchus most primitive in the Tylenchida. Of the above- (Geraert & Raski, 1987). Geraert and Raski (1987) mentioned taxa only Aletylenchusand Psilenchus have characterized this general anterior-end shape as being an amphid situated posteriorly in the cephalic base. In Filenchus-like, i.e. the amphid being postlabial, slit- Phylogeny of Tylenchida like, ventrally curved (the structure of the lateral slit-like amphid of Atetylenchus becomes transversal complex of Tylenchidae, to which Fibnchus belongs, (Psilenchus) and is repositioned in the labial sensory is examined below). Therefore the amphid of zone (Antarctenchus;Fig. 2). The stylet in Psilenchus Atetylenchus is an example of the most primitive is devoid of knobs, as in Atetylenchus. Stylet knobs are amphidial form and position. The transverse slit-like present in all other genera in the order Tylenchida. amphid of Psilenchus appears to be a development Also in Antarclenchus only four submedian papillae from the ventrally curved amphid of Atetylenchus. In remain from the peristomal sensilla of the second and SEM micrographs of Psilenchus sp. from New Zealand third circle (4 + 4) (Fig. 2). (Sher & Bell, 1975) the ventrally curved slit-like Doichodorus. In the amphid amphids, located in the postlabial zone, were readily remains longitudinally stretched, postlabial (Fig. 2), apparent. Atetylenchus may therefore be considered as but the cephalic region in this genus is transformed the most primitive form in the order Tylenchida by its into a 4-lobed structure with a strongly developed lateral complex structure. This genus also possesses a labial disc. These developments of the lip region are weakstylet, lacking knobsand the primitive tylenchoid correlated with the enlargement of the stylet in oesophagus. Within the Tylenchida only Atetylenchus Dolichodorus. Nematodes of this genus are and Psilenchus possess a stylet without knobs. In other ectoparasites of roots. Similar changes of the lip region, tylenchids this protmsible stoma has 3 knobs, to which - an enlarged stylet, an enlarged labial disc and the the protractor muscles are attached. The stylet of presence of a 4-lobed lip region have developed in Atetylenchus resembles the tubular stoma of the parallel with the Belonolaimidae, which also are primitive Secernentea (orders , ectoparasites of roots. The parallel development of the ). A stylet without knobs also occurs in lip region shape in Dolichodorus and belonolaimids is the related order Aphelenchida, i.e. corresponds the believed to be the result of similar adaptation to the out-state for the character. In the tylenchoid protraction of the large stylet. oesophagus the glandular part forms a non-lobed The lip region is the bearing for the stylet compact body followed by the cardia, i.e. oesophageal prdtractor muscles. As every bearing, the lip region sphincter (Fig. 3. A). In the more developed should be steady to deformation displacements, specialized genera of Tylenchida the posterior part of caused by outer forces. The deformation can be elastic the oesophagus is transformed secondarily into the (reversible) or residual. With elastic deformation the gland lobe and the cardia is displaced anteriorly body shape is restored to the initial shape after the (Filipjev, 1936; Paramonov, 1970; Seinhorst, 197 1 ; cessation of loading, but residual deformation is non- Siddiqi, 1971; Ryss, 1987; - Fig. 3. D). Therefore reversible. The cephalic framework prevents non-re- Atetylenchus may be considered the most primitive versible deformation of the lip region arising from genus in the Tylenchida by the structure of the lateral contraction of the stylet protractor muscles. complex and other characters. The vector forces in the lip region are presented in / Fig. 1. H. The protractor muscles attach. to the body Evolution of the lateral complex in wall near the junction of the cephalic framework basal those genera of the suborder Hoplolaimina which are rela red to plate with the body wall. This point is marked on the A tetylenchus diagram by the letter A. Also the muscles may be attached to the basal plate of the framework or to the Psilenchus and Antarctenchus. Development of vestibulum extension (Fig. 1. F). The protractor the lateral complex in the line Atelylenchus - muscles contract during protraction of the stylet. The Psilenchus - Antarctenchus are evident. The force of the strain FI acts along the lines AB and AlBl development of the lateral complex concludes in a (Fig. 1. H). Here the outer surface of the lip region (the change of form and position of the amphid. The initial curved contour ACD) is influenced by an expansion force, and the base of the lip region (the straight the protractor muscles of the stylet. The high arched segment AE in the flatness of the cephalic framework lobed form of a lip region therefore should be basal plate) is influenced by a pressure force. considered as an adaptation to the increased pressure Naturally, the longer and more robust the stylet, the loading in the long-stylet tylenchids. greater are the expansion and pressure forces. It is Thus, the lobed, high arched, shape of a lip region caused by the enlarged mass of the stylet as well as by should be optimum for the maximum strains of the enlarged mass of the stylet protractor muscles. expansion and pressure arising from the stylet During expansion the tensile strength of the lip movement outside the body. Probably therefore the region surface is important. The curved contour ACD 4-lobed shape of the lip region arose independently in has a reserve of length for the expansion. This reserve Dolichodorus and Belonolaimidae, the two taxa of is characterized by the difference between the length ectoparasites with long stylets. of the curved segment ACD and the length of the According to the lateral complex, particularly in straight segment AD. The more curved the segment amphid shape, the genus Dolichodoruscould be traced ACD, the more stable the lip region is to the expansion from Atetylenchus only (Fig. 2). The set of secondary force. Therefore, the lip region in the long-stylet transformations in Dolichodorus are: deirid is tylenchs is highly curved. It can be considered as an reduced, lateral field transforms from the 3-band adaptation to cope with the increased loads. structure (4 incisures) in Atetylenchus into a Zband During loading the curve ACD tends to become one (3incisures) in Dolichodorus, tail is shortened and straighter. It means that the lip region undergoes the in connecting with it the initial adanal bursa of ring-shaped expansion strains during contraction of Atetylenchus has been transformed in Dolichodorus the protractor muscles. These strains increase, as the into the pre-phasmidial adanal-termina1,'i.e. into the curvatureof thecorresponding part of thecontour ACD terminal bursa 'with a distinct posterior gap between increases. The reserve of the cuticular surface in the tail and caudal alae (Fig. 2). form of longitudinal folds in the lip region is necessary Meiodorinae with its pore-like amphid located in for the tensile strength of this expansion strain. In Yhe the labial sensory zone it evidently may be traced only long-stylet tylenchs the lip region has the 4-lobed from Antarctenchus. In the Meiodorinae the stylet shape with longitudinal folds (depressions) between becomes massive and as a result of the tail shortening lobes. The lobed shape of a lip region can also be the pre-phasmidial bursa transforms from adanal into considered as an adaptation to the increased loads. adanal-terminal. The genus Hirschmanniella is The resistance of the cephalic framework base to closely related to Meiodorinae by the structure of the pressure depends not only on the solidity of the basal lateral complex. Earlier this genus was considered in plate of the framework (the vector of the resistance the family Pratylenchidae. Hirschmanniella differs force of skeleton material F2 along the axis AE is however from the Pratylenchidae and from other H) indicated on Fig. 1. but also on the projection of the higher hoplolaimoid families by the non-division into maximum radial line of the cephalic framework (Fig. sectors of the lip region into sectors (this feature is 1.8), the vector of the resistance force of skeleton peculiar to meiodorins as well) ;and by the lateral field material F3 along the axis EC) on the cephalic not reaching the hyaline portion of the tail terminus, framework base (F3' along the axis AE). Therefore, by the adanal bursa not reaching the terminus and by the greater the maximum radius of a lip region EC, the phasmids in males not forming ribs on the caudal passing through the radial septa (the blade) of the lip alae, as occurs in pratylenchids and other region skeleton, (i.e. the more high arched the outer hoplolaimoid families, but are arranged on the tail as contour of the lip region ACD) , the greater the solidity in Meiodorinae. These characters suggest that the of the skeleton base along the line AE. Also its meiodorins and Hirschmanniella be considered as a resistance is increased to possible strains, caused by family Meiodoridae n. rank consisting of 2 subfamilies: Phylogeny of Tylenchida

Meiodorinae including the genera Meiodorus and also do not reach the tail terminus. The bursa of these Brachydorus and Hirschmanniellinae including the taxa is pre-phasmidial, adanal. In Pratylenchoidesand single genus Hirschmanniella only. Merliniinae the bursa becomes terminal, caudal alae SEM photographs of the lip region in Meiodorus enclosing the tail tip, - in connection with the lateral festonatus have been published (Doucet, 19851, of field displacement to the terminus. Phasmids, that in Hirschmanniella: H. miticausa (Bridge et al., 19831, Atetylenchus, Psibnchus and Antarctenchus are H. spinicaudata (Aubert & Luc, 1983, H. mucronata positioned posterior to the caudal alae on the tail, are (Siddiqi, 1986). Six inner lip papillae and 4 submedian situated in Pratylenchoides and Merliniinae on the groups each of 2 papillae are seen distinctly in the caudal alae, forming the so-called <. photographs of H. mucronata. In Meiodorus The phasmidial processes extend from the phasmidial festonatus there are 6 inner lip papillae and 4 bulb to reach the caudal alae margin (the phasmidial submedian papillae. Thus the complete composition of bursa - Fig. 1. Dl. On the basis of the lateral complex 6 + (4+4) peristomal sensilla may be considered as the structure Pratylenchoides and Merliniinae may be primary state for Meiodoridae (Fig. 2). considered as the single family Merliniidae n. rank, possessing the complete composition of a lateral ~rat~lenchoidesand Merliniinae. With reference complex and the reaching terminus lateral field of to the above taxa which have a fully developed lateral females and the phasmidial bursa of males. complex, other members of the group i.e. Pratylenchoides and Merliniinae have a significant Belonolaimidae and families of the higher plant transformation of the lateral complex as opposed to parasitic Hoplolaimina. The following characters of that in the line Atetylenchus - Psilenchus - the lateral complex: terminal bursa with 'phasmidial Antarctenchus. In Atetylenchus, Psilenchus, ribs', reaching terminus lateral field of females, Antarctenchus, Dolichodorus, Meiodoridae a lateral arrangement of transversal and pore-like amphids in field, consisting of several bands (usually 3) at mid- the labial sensory zone indicate that belonolaimidsand body, becomes narrower towards the body ends and the families of the higher plant parasitic Hoplolaimina: transforms from a wide strip into 1 line on the cuticle Tylenchorhynchidae, Hoplolaimidae, Rotylenchulidae, surface. This line terminates, before reaching the tail , Pratylenchidae, Nacobbidae, tip, or the tail hyaline level (Fig. 2). In Pratylenchoides Meloidogynidae are related to the Merliniidae and and Merliniinaea lateral field reaches the tail terminus may have arisen from the latter (Fig. 2). In all these (at least the level of the hyaline zone of the tail) in the families the reduction of a deirid took place. It may be form of a wide strip consisting of 3 or 5 bands (Fig. 2). supposed that the Belonolaimidae are the most ancient Therefore the lateral chords, of which the surface group among the higher hoplolaimoids, since the structures are lateral fields, are combined with a amphid remains on the margin of the labial sensory thickened hypodermic hyaline zone at the terminus, zone. A pore-like amphidial orifice is situated at the forming a joint structure. This structure, with lateral margin of a small tube (= the lateral lobe of the lip hypodermic chords, appears to represent a single region according to some terminologies). This tube framework. The formation of such a framework begins in the anterior part of the cephalic base. possibly improves the flexibility of the tail. The Comparison of this amphidial structure with the structure of the male tail changes as a consequence of primitive one for Tylenchida (the amphid of the lateral field displacement to the terminus. Male Atetylenchus) may suggest that the amphidial tube of caudal alae, which help to hold a female during the belonolaimids represents the closed longitudinal copulation, are derivatives of the lateral fields folds slit of the amphid of the primitive tylenchs. The orifice (Fig. 2). In Atetylenchus, Psilenchus and of the amphid of belonolaimids therefore represents Antarctenchusa lateral field does not reach the hyaline the anterior part of the initial slit-like orifice of the portion of the terminus and consequently caudal alae primitive Tylenchida. Evidently, such an amphid is more primitive than the transversal or pore-like 3. D). Detailed investigation of the oesophageal amphid found in hoplolaimoid families. This suggests transformations in Tylenchida and of their an early separation of the belonolaimids from the significance for the systematics of the order were higher hoplolaimoids. In the present paper the family carried out for the first time by Seinhorst (1971) and Belonolaimidae is considered in the context of the Siddiqi (1971). The secondary (in comparison with the subfamily Belonolaiminae sensu Siddiqi, 1986 only, tylenchoid) lobed structure of the oesophageal glands i.e. in the following generic content: Belonoluimus, in Belonolaimidae points to a combination of primitive Ibipora, Carphodorus, Morulaimus. This family hoplolaimoid structural peculiarities of the lateral appears to represent a natural taxon. The genera complex and derived characters in the oesophageal included in it are similar by having a hypertrophied gland structure. stylet, 4-lobed shape of the lip region, spiculae shape, gubernaculum with titillae and the distal end curved Transformations of the lateral posteriorly and by the presence of an epiptigma at the complex in Tylenchina vulva. Within the Belonolaimidae all genera, apart The characteristic feature of the three orders is from Belonolaimus, possess 3 bands in the lateral the absence of phasmids on the tail. The male bursa is field. Also, in Carphodorus there are 3 lateral field usually adanal and devoid of phasmids. The absence bands, of which only the inner one is distinct. In of phasmids is secondary as all other orders of the Belonolaimus spp. the lateral field has a single incisure subclass Secernentea possess phasmids. only. It is obvious from a comparison of the lateral The suborder Tylenchina is considered here to be complexes of the tylenchids that in Belonolaimus a comprised of the families: Tylenchidae, Atylenchidae, secondary reduction in the lateral field structure took Tylodoridae, Ecphyadophoridae, i.e. its composition place. corresponds to the superfamily sensu Among the above-mentioned higher plant Siddiqi, 1986. Within the Tylenchina the most close to parasitic hoplolaimoid nematodes the most primitive Ateiylenchus is the family Tylenchidae. In ones are undoubtedly those taxa of the subfamily Tylenchidae there is a longitudinal slit-like ventrally Tylenchorhynchinae of the family curved amphid situated near to the cephalic base (i.e. Tylenchorhynchidae with their typically tylenchoid posterior to the labial sensory zone) and a complete oesophagus (Fig. 3. A, E, H). In the rest of the families labial sensory complex (see, for example, SEM and in the subfamily Telotylenchinae of the family photographs in: Sher & Bell (1975); Siddiqi (1986); Tylencfiorhynchidae the heterotopy of the Fortuner et al. (1987,1988). This type of amphid has oesophageal glands arises in connection with the been designated by Geraert and Raski (1987) as being increase in the gland volumes and with an Filenchus- like. By the presence of ventrally curved intensification of the gland function. The glands could postlabial amphids it may be concluded that the no longer be disposed at the same level in the narrow Tylenchina are the most primitive among the three nematode body as in the primitive tylenchoid type of non-phasmidial suborders. Tylenchina possess a the oesophageal structure. Therefore, the heterotopy clear-cut synapomorphy: phasmids are absent on the of glands arises at the same time as a reduction in the tail, but there is a pair of phasmid-like structures in the cardia and its forward displacement (Ryss, 1987, postmedian part of the body, dorsal to thelateral field. 1988). In higher hoplolaimoids the primary subventral It is premature to speak about the homology of these glands (with small nuclei) are the longest. In the family phasmid-like structures to phasmids in siiu, since no Belonolaimidae, and in the subfamily Telotylenchinae investigations on the innervation have been carried of the family Tylenchorhynchidae, in which similar out. The position of them outside the lateral field (i.e. processes in the gland lobe formation occured, the outside the typical lateral complex) calls into question dorsal gland (with a large nucleus) is the longest (Fig. such a homology. In othersecernentea such a structure Phylogeny of Tylenchida has not been observed. Siddiqi (1978, 1986) first 1988; Chizhov & Kruchina, 1988, 1992) on the basis reported these phasmid-like structures as important of a comparative morphological investigation of the taxonomic characters and the synapomorphy for female genital system. However these authors did not Tylenchoidea. Within Tylenchina the transformation present a clear-cut differential diagnosis for the 2 of shape and position of the amphid takes place (Fig. suborders and the characteristics of the complexes of 2). It becomes straight, longitudinal, slit-like, located synapomorphies for the most derived from the two in a cephalic base, then transforms to pore-like, taxa. Within Hoplolaimina the forms with reaching moving into the labial sensory zone (Miculenchus: terminus lateral fields and the terminal bursa can be Geraert & Raski (1987) - see Fig.2. segregated as the superfamily Hoplolaimoidea, including all advanced plant parasites and the remaining paraphyletic primitive forms (including Taxonomic borders of Tylenchina and Hoplolaimina and the Atetylenchus) which, not possessing synapomorphies taxonomic division of the order of that rank, can be designated as the superfamily Hoplolaimina Dolichodoroidea. In the latter the genus Dolichodorus can be designated as the monotypic family ~arlierTylenchoidea were considered the most Dolichodoridae bv the sha~eand ~ositionof the slit- primitive group in the order; it had been joined in one like amphid, the 4-lobed lip region and a long stylet. suborder with the hoplolaimoid forms. Nevertheless, a Another,monophyletic group of long-stylet nematodes secondary absence of the tail phasmids and a with pore-like amphids are represented by the family secondary synapomorphy in the form of the phasmid- Meiodoridae n.rank. The remaining taxa segregated like structure is a basis to consider this group as the from the dolichodorids and meiodorids represent a monophyletic, secondary specialized taxon in the rank paraphyletic group of the most primitive Tylenchida, of the suborder Tylenchina. The hoplolaimoid forms: including the genera Atetylenchus, Psilenchus, Aletylenchus and the groups close to it may be Anlarctenchus. It is logical to consider these genera as designated as a separate suborder, Hoplolaimina, a separate family - Psilenchidae which corresponds including the most primitive forms lacking the obligate with the family suggested by Siddiqi (1986). synapomorphies for the suborder. When a taxonomic By their biotopic characteristics the Hoplolaimina subdivision is proposed only one of the two newly are in general advanced plant roots parasites, established groups will possess a complex of inhabiting the mineralized soil levels. The Tylenchina synapomorphies, and the other group represents the as well as the Psilenchidae under Hoplolaimina inhabit remainder of this new taxonomic subdivision. The the moss-lichen and the litter layers. group possessing synapomorphies is monophyletic and derived and the group lacking synapomorphies group The history of the systematics of is paraphyletic and includes the primitive forms, and Hoplolaimoidea and the the taxa related to them. For example, when significance of the oesophageal gland structure for the Secernentea, which is the derived taxon possessing determination of the taxonomic synapomorphies, was proposed within Nematoda, the limits of the hoplolaimoids other taxon - Adenophorea was diagnosed as lacking these synapomorphies. Subsequently, in a similar The majority of the Hoplolaimoidea taxa typically manner the subclass Enoplia was segregated from possess an oesophageal gland lobe, in which the 2 Adenophorea with the remaining taxa in the primary subventral glands are longer than the dorsal subdivision placed in the subclass Chromadoria. gland (Fig. 3. B & C). Only in Belonolaimidae and Among the latter are the most primitive taxa of Telotylenchinae (Tylenchorhynchidae) is the primary Nematoda. Earlier the subdivision to Hoplolaimina dorsal gland longer than the subventral gland (Fig. 3 and Tylenchina was proposed (Chizhov & Berezina, D). The biological significance of the transformation of the oesophagus from non-lobed to one containing a posterior to the oesophageal-intestinal junction. Using gland lobe may be accounted for as follows. this character, the authors re-established the Specialization to plant and the superfamily of the higher phytophages intensification of the oesophageal gland function Hoplolaimoidea, which had been proposed by occurs and the gland volume increases. This is caused Paramonov (1967)- but in a narrow taxonomic context by the necessity to dissolve plant cell contents by (without the criconematoid forms). Proposing the secretions from these glands injected through the superfamily, Paramonov ( 1967) did not give a clear stylet capillar into the host cell. The enlarged glands differential diagnosis and therefore the name cannot be arranged at the same level in the narrow Hoplolaimoidea was used by taxonomists as a junior nematode body. Their heterotopy evolves so that the synonym of Tylenchoidea only. Siddiqi (1980) gland bodies become arranged in a single row forming attempted to re-establish Hoplolaimoidea as a natural a lobe and their their primary positions - one large group of the advanced plant parasitic forms but again dorsal and two subventral - are changed (Fig. 3). The he did not gave a clear differential diagnosis for the new arrangement is determined by the lobe position, taxon. Later Siddiqi (1986) used the arrangement of which may be dorsal or ventrosublateral. The cardia, the oesophageal glands for the differentiation of initially lying posterior to the gland bodies on the Hoplolaimoidea. According to his diagnosis, the boundary of the oesophagus and intestine, moves to primary subventral glands in Hoplolaimoidea lie the anterior border of the oesophageal glandular part posterior to the dorsal gland. It is clear that the and undergoes a partial reduction of muscle fibers. In oesophageal gland lobe with 2 subventral glands at the the most specialized types of the oesophagus the end formed more than once in the evolution of cuticular oesophageal intestinal valve retains from the Tylenchida. It occured independently within cardia. With thecardia theanterior part of theintestine Pratylenchoides (the line P. sheri, P. heathi with an moves forward so that the gland lobe overlaps the abutting oesophagus - P. ritteri, P. megalobatus with a intestine (Fig. 3. B-D). This displacement may occur large giant lobe) and within Hoplolaimidae (the line between the subventral glands - in this case the mid- Pararotylenchus with an abutting oesophagus - intestine pushes the gland lobe dorsally (Fig. 3. B, F, Helicotylcnchus - Hoplolairnus with a gland lobe). The I) or between the subventral and dorsal gland.In this transformation of the glands of the tylenchoid case the anterior part of the intestine pushes the gland oesophagus into the oesophagus with a glandular lobe lobe ventrosublaterally (Fig. 3. C, G, J). Thus, the ending by the primary dorsal gland took place in the formation of the lobe and the oesophageal gland line: subfamily Tylenchorhynchinae - heterotopy is important for the evolution of forms with Telotylenchinae within the family the exointestinal digestion, which excrete gland Tylenchorhynchidae, which is closely related to the secretions into host tissues to assist in the feeding higher hoplolaimoids (Fig. 3. A & Dl. The same process. To these nematodes belong the plant feeders structure has a gland lobe in the family Belonolaimidae since every cell on which a nematode feeds is enclosed (= subfamily Belonolaiminae sensu Siddiqi, 1986) into a massive cellulose wall. The biological which is very close to the group of higher plant feeders; significanceof the oesophageal gland lobe formation in it evidently developed such an oesophageal structure the evolution of the parasitic nematodes was explained independently of Telotylenchinae. Oesophageal gland by Ryss (1987, 1988). Earlier Ryss and Krall (198 I) lobe formation therefore evolved in the plant feeders proposed the use of the structure of the oesophageal more than once. The formation of the lobe with glandular part for the segregation of the group of the subventral glands at'the end, and the formation of the higher plant parasitic Tylenchida. According to these lobe with the dorsal gland at the end occurred authors, the higher phytophages are the families repeatedly in the evolution of the Tylenchida. The possessing a lobe in which 2 subventral glands lie classification proposed by Fortuneret al., (1987- 1988) Phylogeny of Tylenchida also points to the parallelism in the formation of the the amphid is in the form of a longitudinal slit, gland lobe in different taxa of tylenchids. Heterotopy beginning anteriorly from the labial disc and coming of glands and the oesophageal gland lobe occured into a cephalic base. In Neodolichodorus the amphid is repeatedly in the parasitic Tylenchida probably a small dorso-ventral slit, located in the labial zone. In because of an intensification of gland cell secretions Nematoda the shape of the amphid aperture is very which were used in the feeding process of these stable and is used as an important character for nematodes. Formation of a lobe is connected with diagnostics of the higher taxa, up to subclasses. reductions in the initial tylenchoid glandular bulb i.e. Therefore, the unification of Dolichodorus and reductions in connections between 3 glands and a Neodolichodorus into a single supergeneric taxon cardia, cardia reduction and with reductions of appears illogical. It is clear from the aforesaid analysis connections of the glandular bulb with the body wall. that the form and position of the amphid in Therefore the gland lobe formation (and its particular Neodolichodorus is more derived than in Dolichodorus types) may be considered as the developmental and corresponds to the amphidial form and position in specialization to phytophagy. This kind of An farclenchus and Meiodoridae n. rank. By the pre- specialization is accompanied by the foregoing phasmidial adanal-terminal bursa and absence of the reductions and this is typical for the evolution of the deirid it is logical to consider Neodolichodorus under parasitic adaptations. Neither the presence of a lobe, Meiodoridae and to arrange in the typical subfamily nor its peculiar types determine the large Meiodorinae together with Meiodorus and monophyletic groups, but only characterize the Brachydorus. Lateral fields in females of adaptation trend arising in parallel different phyletic Neodolichodorus as disti~ct from the other lines. In this paper the lateral complex structure and Dolichodoroideareach the hyalinepart of the tail. This not the morphology of the glandular part of the feature is an obligate character in Hoplolaimoidea. In oesophagus is used for the differential diagnosis of the Neodolichodorus the displacement of the lateral fields Hoplolaimoidea. to the terminus is caused by the distinct secondary shortening of the tail, especially by shortening in its The taxonomic position of Neodolichodorus ventral side. This has resulted in the phasmids having been moved to the level of the anus or even more anterior. This shortening of the tail and the shift of In classifications by Siddiqi (1 986) and Fortuner phasmids took place in parallel with the typical family et al., (1 987- 1988) Neodolichodorus is considered as of the Hoplolaimoidea - Hoplolaimidae - in the genera the most close taxonomically to Dolichodorus. In Helicotylenchus and Rolylenchus. In the hoplolaimids Siddiqi's (1986) classification both genera have been Helicofylenchus multicincfus and H. vulgaris the combined in the subfamily Dolichodorinae, family shortening of the tail (in thechangeof an index c') and Dolichodoridae. In the classification of Luc and the shifting forward of the phasrnids were traced in a Fortuner (1987) both genera and Brachydorus are life history (Zuckerman & Strich-Harari, 1963; Yuen, placed in the family Dolichodoridae (without a 1966). In the type-species Neodolichodorus obtusus subdivision to subfamilies) . Neodolichodorus and the early stage juveniles have a spicate tail, typical for Dolichodorus are the nearest with a long stylet and the Dolichodoroidea (Siddiqi, 1986). The presence of tylenchoid oesophagus. However the lip region of the pre-phasmidial adanal-terminal bursa and shape Neodolichodorus is rounded and not 4-lobed as in of the tails in the early stage juveniles suggests the Dolichodorus. In Neodolichodorus the prominent position of Neodolichodorus in the superfamily labial disc is absent, but the disc is prominently Dolichodoroidea, in the family Meiodoridae is developed in Dolichodorus. The main difference is in phylogenetically justified. the form and position of the amphid. In Dolichodorlis -- Lateral complex of Hexatylina There are 6 inner labial papillae around the stoma; in the second circle 4 groups each with 2 pore-like papillae Representatives of this suborder are devoid of can be distinctly seen in the photographs in the book phasmids and phasmid-like structures. Their amphids by Siddiqi (1986). This arrangement seems to are labial, always located dorso-sublateral (Fig. 2). correspond to the initial Hexatylina structure of the The main part of the suborder are the specialized peristomal sensilla complex: 6 + (4 submedian + 4 entomoparasites which have a complex life-cycle, often submedian). In other micrographs - for example see including an alternation of generations. In the the face view of Hexatylus, Nothotylenchus, entomoparasitic Hexatylina thereare reductions in the Safianema, Anguina, Cynipanguina in Raski and oesophageal structure and the female reproductive Maggenti (1983) only the four submedian papillae system is often hypertrophied. Members of the could be recognized in the second circle. Four cephalic Anguinidae are the closest family to other suborders of papillae were indicated by Siddiqi (1986) as a typical Tylenchida. Anguinids are usually parasites with a and obligate character of Hexatylina. simple life-cycle. They are mycophages and agents of combined nematode-fungus infections of plants. The Homologies following from the higher anguinids - the genera Anguina, Suban,guina, structure and position of the amphid in Hexatylina Cynipanguina and others are parasites of the aerial parts of plants, forming galls each with a nematode The dorso-sublateral amphids located on the colony consisting of adults, juveniles and eggs. Higher margin of the labial zone are typical for hexatyls in the anguinids have a hypertrophied female reproductive primitive Ditylenchus, in Pseudhulenchus and in system containing a large number of synchronous eggs Hwalylus, Anguina and Cynipanguina (Raski & and a secondarily transformed oesophagus with a Maggenti, 1983); the amphids are stretched in the gland lobe. The formation and enlargement of the lobe form of an oblique slit (Fig. 2). In the forerunner to can be easily seen in the ontogenesis by comparing the Hexatylina as in other primitive nematodes, the second stage juveniles possessing a tylenchoid amphid was situated posterior to the labial zone. It is oesophagus with juveniles of the following stages and obvious from the shape of this organ in the adults (Ryss & Krall, 198 1). Species closest to other contemporary Hexatylina that its aperture repre- Tylenchida are in the genus Ditylcnchus and they sented a longitudinally stretched slit. It is difficult to possess the tylenchoid oesophageal structure and the elucidate whether this slit on the lateral surface of the non-hypertrophied female reproductive system. The head cuticle was straight or curved ventrally or lateral complex of Dilylenchus shows a resemblance to dorsally. With theshift of the amphid to the labial zone other Tylenchida with phasmids and phasmid-like the projection of the amphidial aperture in the frontal structures being absent. The lateral field does not plane (or of the lip region plane proper) should be reach the hyaline part of the tail, therefore, the bursa retained, as it is perpendicular to the initial plane of is usually adanal, sometimes subterminal. The lateral the amphidial aperture position. As the slit-like and field may contain a large number of bands (3-5, pore-like amphids of Hexatylina open always dorso- sometimes 7) with the initial number probably being 3 sublaterally, one can conclude that the terminal part bands (4 incisures) as in other Tylenchida (Fig. 2). A ;f the amphidial canal was situated in the same deirid is present as in other Hexatylina. The amphid position in the ancestral Hexatylina. According to the is slit-like, located in the labial sensory zone (see SEM comparative-anatomical investigations of the whole micrographs in Siddiqi, 1986; Raski, Maggenti, 1983). class Nematoda (Lorenzen, 198 1) this feature is char- The amphidial slit extends from the margin of the acteristic of the primary ventrally curved amphid. labial zone and passes longitudinally inwards to the Therefore the initial dorso-sublateral labial amphids oral opening. The slit is orientated the dorso-medially. of hexatyls are suggested to have arisen from the Phylogeny of Tylenchida postlabial longitudinal ventrally curved amphids. It is labial sensilla open in the prestoma. In other logical to derive therefore the lateral complex of Criconematina - Hemicycliophoroidea and Hexatylina from the lateral complex of Tylenchina. Criconematoidea the reduction of the deirid and the The tylenchoid oesophageal shape in the primitive lateral field took place, evidently caused by the Hexatylina also points to such relationship. formation of the peculiar coarsely annulated cuticle. Nevertheless, the structure of the cardia in anguinids To which of the two non-phasmidial suborders - is distinct from that in Tylenchina and Hoplolaimina. Tylenchina or Hexatylina do the Criconematina most In anguinids this part has the two anteriormost closely resemble can be deduced as follows. Hexatylins modified cells of the intestine (Siddiqi, 1986), whereas differ significantly from Tylenchuloidea by the position in hoplolaims and tylenchs thecardia is tricellular. The of the amphidial aperture which is always dorso- primitive Hexatylina are supposed to be Dilylenchus- sublateral. On the other hand in Tylenchina similar like mycophagous nematodes inhabiting the litter. transverse labial amphids occur (Miculcnchus, Filcnchus Subsequently they evolved as agents of the complex chilensis; Geraert and Raski, 1987). The presence of fungus-nematode infections of the aerial parts of submerged peristomal sensilla and the criconematoid plants (Patamonov, 1962, 1970). The descendants of oesophagus where the procorpus has amalgamated with the mycophages and phyto-mycophages became the metacorpus indicates that Criconematina entomoparasitic hexatylins with complex life-cycles significantly differ from Tylenchina, more so than including the alternations of generations (Chizhov & Hexatylina differ from Tylenchina. Therefore it may be Kruchina, 1988), or higher plant-parasitic gall- concluded that Criconematina separated before forming nematodes inhabiting theaerial parts of plants Hexatylina from the Ty lenchina (Fig. 5). - Anguina, Subanguina, Cynipanguina (Anguinidae) (Paramonov, 1962, 1970). Correlation of morphological characters accompanied by Transformations in the lateral transformations of the lateral complex of Criconematina complex: diversity in the female reproductive system The majority of the Criconematina have peculiar In contrast to the primitive Hoplolaimina, the tail scale-like, coarsely annulated, cuticle with a specific phasmid of 3 other suborders disappeared. Also the musculature. Nematodes of the superfamily posterior branch of the primitive didelphic female Tylenchuloidea are the closest in appearance to the reproductive system became reduced in these tylenchoids. These are cylindrical nematodes with finely annulated cuticles. On this basis the suborders. Initially the female genital system in Tylenchuloidea are considered the most primitive nematodes was didelphic. Among Tylenchida the Criconematina. The lateral complex of didelphic system is predominant in the Hoplolaimina. Tylenchuloidea is similar to that of Tylenchina and During rnorphogenesis the didelphic system develops Hexatylina: phasmids are absent, a lateral field does in the form of 2 branches of the genital primordium. not reach the narrowly conical tail and accordingly the There is a germinal cell originating in an ovary at the male bursa is usully adanal or absent. A deirid is end of each branch. In rare cases where the genital present. The important differences from other non- system of hoplolaims consists of a single anterior phasmidial suborders are in the structure of the labial branch (Prcttylenchns), the posterior branch of the sensory complex and form of the amphid. The amphid genital primordium with the posterior germinal cell is labial in the form of a dorso-ventral slit (Fig. 2). The does not complete its development (Roman & sensilla of the labial complex are submerged, openings Hirschmann, 1969; Ryss, 198 1, 1988) - see Fig. 4. of the papillae are absent on the surface of the lips, This is evidence of the didelphic genital tract that amalgamated around the I-shaped oral opening. Inner remains in ontogenesis (Ryss, 198 1 ). In taxa of the 3 non-phasmidial suborders the single germinal cell is situated at the end of the single anterior branch of the genital primordium. Therefore specialization to a single tract has gone further and it is probably more ancient in the non-phasmidial suborders. The single female genital tract is wide- spread not only among tylenchids, but also in other groups of Nematoda. The biological expediency of its acquisition, or more precisely of the reduction of the posterior branch of the primary didelphic genital tract is probably as follows. In females with the primitive didelphic reproductive system the genital opening and the reproductive system sections depositing a completely developed egg are situated in the middle of the so-called trophico-genital part of a body (terminology after Paramonov, 1962), i.e. the mid- body. In nematodes with a unpaired female reproductive system the genital opening and the egg- depositing sections of the genital tract are displaced to the posterior border of the mid-body (Fig. 4. G & H). The trophico-genital section is the main part of the body length, where the main part of the dorso-ventral undulation wave, going along the body, is settled. A nematode proceeds by means of this wave. A completely developed egg in Tylenchida occupies nearly all the body diameter near the genital opening. Fig. 4. Types of postembryorlic morphogenesis in the female reproductive system of Tylet~chida(A-F) and the arrangement of the The flexibility of the mid-body at this point is female genital system and its egg-depositil~gsections in the nematode important for undulation and movement. A body (G,H). displacement of the vulva and the egg-depositing A-C: Types of genital primordium of second-stage juveniles; D-F: sections of the genital tract to the posterior end of the Types of developme~~tof the genital primordium in ontoget~esis. Directions of the morphogel~eticmovement of the germinal cell in the mid-body section should increase the flexibility of the developi~~ggerlital primordium are marked by arrows. A, D: whole body especially the trophic-genital part. In Morphogenesis of the female reproductive system of the didelphic Hoplolaimina; B, E: Morphogenesis of the female reproductivesystem Tylenchida and in a majority of other Nematoda, with of the mol~odelphic (pseudomot~odelphic) Hoplolaimi~ia rare exclusions in the order Dorylaimida (families (Pratylerrchus); C, F: Morphogenesis of the female reproductive system of Tylenchilla and Hexatylina; G:Positio~~ of the reproductive Belondiridae, Longidoridae) the reduction occurs in system in didelphic Tylenchid;~ (Hoplolaimina); H: Position of the the posterior genital branch. This has probably reproductive system in morlodelphic Tylenchida. Sections of the reproductive tract, depositing a completely developed as a result of it being easier to pull a rigid developed egg (a preuteral gland - a crustaformeria and an uterine widened part of the body containing an egg than to sack) are marked by the black colour. gc -germinal cell, tgo - trophico- genital (the middle) part of a body, vu - vulva. push it forward.' The latter case would occur if the genital opening would be situated anteriorly from the applied to an object, but the force of a push may is trophic-genital part, which is the main propulsive limited. undulative agent of the nematode body. A direct Earlier the reduction of the posterior branch of the analogy lnay be that of the nematode and a cord. By female genital tract has been interpreted by some means of the latter a greater pulling force may be authors as the deliverance of the posterior part of the Phylogeny of Tylenchida The primitive niche and niche diversity

Following the pattern of phylogenetic relationships developed in the analysis above (Fig. 5) the evolution of the niches for the order Tylenchida may be proposed. It is premature to analyse the evolution of the nutrition requirements and food sources of different taxa. Biotopes colonised by Aletylenchus, Psilenchus, Anturctenchus and Tylenchina may be considered primitive niches for the order. These are litter and the above-ground moss- lichen layer. The descendants of the primitive Tylenchida have progressed to parasitism in and on roots of the higher plants from these initial niches. Thus the majority of Hoplolairnina and Criconematina RHABDITIDA I have moved into the mineral soil layers. From the initial niche, more branches, including Diiylenchus- like forms, evolved as entornoparasites or parasites in SECEBNENTEA galls on aerial parts of plants i.e. Hexatylina. CHROMADORIA: LEPTOLAIMINA The origin of Tylenchida

The author of the present paper shares the view that Tylenchida and Aphelenchida originated from Rhabditoid-Diplogastcroid ancestors (Fig. 5). These Fig.5. The diagram of phylogenetic relationships of the order Tylenchida and of the ancestry of the latter. views have been described in classical papers by Filipjev (1934), Chitwood & Chitwood (1950), worm body from an obstacle to a movement. The Paramonov (1 970) and Andrassy (1976). The posterior ovary and oviduct have been considered as primitive Tylenchida - Alctylenchus - correspond to the obstacles (Paramonov, 1970; Chizhov & Kruchina, the characters of the lower Secernentea by the 1988, 1992). But when the vulva is moved to the structure of the lateral complex: ventrally curved posterior the posterior body cavity becomes filled postlabial amphid, presence of a deirid and phasmid, again by the anterior genital tract. Therefore, the and having3 bandsof the lateral field. According to the above-mentioned point of view appears unconvincing. opinions of some authors, Secernentea may have In three non-phasmidial orders - Tylenchina, originated from the Chromadoria (Andrassy, 1976; Hexatylina, Criconematina reductions in the posterior Drozdovsky, 1989). The closest to Secernentea taxa body part of females are present. The posterior branch among Chromadoria are the Plectidae which possess a of the female reproductive tract and the tail phasmids deirid and Teratocephalidae which possess phasmid- are reduced. Probably this is connected with an like papillae in the tail. These two families were related opposition of the more mobile part of the body anterior by Lorenzen (1981) to the suborder Leptolaimina in to the vulva to the less mobile part posterior to the the order Chromadorida, which represents the vulva. However in the higher Hoplolaimina (the paraphyletic group located at the base of the phyletic majority of Hoplolaimoidea) a deirid located in the tree of Chromadoria as well as the whole class anterior body part is reduced. Nernatoda. Thus it may be supposed, based upon the lateral complex structure of Ateiylenchus that the Meiodoridae and the group of higher hoplolaimoid origin of the order Tylenchida proceeded very close to families: Tylenchorhynchidae, Hoplolaimidae, the time when Secernentea split from the primitive Pratylenchidae, Rotylenchulidae, Nacobbidae, Chromadoria. Meloidogynidae, Heteroderidae). Phasmid present Keys to the suborders, superfamilies and families (except Aphasmotylenchus in Hoplolaimidae). Lateral of the order Tylenchida as well as diagnoses and field with 4, more rarely 1, 3, 6 incisures reaching taxonomic volumes of the groups, whose contents hyaline part of tail terminus (superfamily differ from that in classifications by Siddiqi (1986); Hoplolaimoidea) or not reaching it (superfamily Fortuner et al., (1987, 1988); Chizhov and Kruchina Dolichodoroidea). Bursa pre-phasmidial: adanal, (1988, 1992), are proposed. adanal-terminal or phasmidial terminal. The paraphyletic group, lying at the base of the Key to suborders of the order phylogenetic trunk of the order Tylenchida. Tylenchida Type family: Hoplolaimidae Filipjev, 1934.

1. Phasmids present on tail (except Ayhasmotyl- enchus), female reproductive system usually paired ... Key to superfamilies of ...... Hoplolaimina Hoplolaimina - Phasmids absent, phasmid-like structures may 1. Male caudal alae enclosing tail tip, phasmidial: present in postmedian body part lying dorsally from phasmids form phasmidial ribs on alae, lateral field of lateral field, female reproductive system unpaired ...... larvaeand females reach hyaline part of tail terminus ...... 2 ... Hoplolaimoidea 2. Phasmid-like structures present dorsally ...... - Male caudal alae adanal or adanal-terminal, from lateral field in postmedian body part (usually pre-phasmidial: phasmids posterior to caudal alae on at level of vulva) ...... Tylenchina the tail, lateral fields of larvae and females do not - Phasmid-like structures in postmedian body reach hyaline part of terminus at significant distance part absent ...... 3 (in Neodolichodor~rs only in juveniles of the youn- 3. Oesophagus criconematoid: metacorpus fused gest free stages) Dolichodoroidea with procorpus, stylet usually occupies whole pro- ...... corpus (in redrawn up state), amphids lateral, slit- Superfamily Hoplolaimoidea like, dorso-ventral, oral aperture I-shaped; parasites Filipjev, 1934 (Paramonov, 1967) of plant roots ...... Criconematina - Oesophagus non-criconematoid, metacorpus Diagnosis. Hoplolaimina. Male caudal alae not fused with procorpus, amphid dorso-sublateral, phasmidial, enveloping tail. Phasmids form slit-like or pore-like, oral aperture rounded pore- phasmidial ribs on tail. Lateral fields of females and form. Mycophages and entomoparasites, parasites of larvae reach hyaline part of tail terminus. aerial organs of higher plan6 ...... Hexatylina Type family: Hoplolaimidae Filipjev, 1934.

Suborder Hoplolaimina Chizhov & Key to families of Hoplolaimoidea Berezina, 1988 (syn. Heteroderata Skarbilovich, 1959) 1. Deirid present ...... Diagnosis. Tylenchida. Amphid postlabial: ...... Merliniidae Siddiqi, 197 1 (n.rank). longitudinal, ventrally curved, V-shaped or dorso- - Deirid absent ...... 2 ventral; or labial: dorso-vental, sometimes pore-like. 2. Lip region 4-lobed. Amphidial apertures on the Deirid present (Psilenchidae, Merliniidae including end of longitudinal non-annulated lateral tubes, Pratylenchoides) or absent (Dolichodoridae, situated in theanterior part of annulated lip region ...... Phyloge~~yof Tylenchida ...... Belonolaimidae Whitehead, 1960. Family Merliniidae Siddiqi, 1971 - Lip region truncated, conical or rounded, am- (n.rank). phids are small slits directed dorso-ventrally or pore- Diagnosis. Hoplolaimoidea. Deirid present. like, located on the lip sensilla zone ...... 3 Amphids labial, small dorso-ventral slits or pore-like. 3. Female body lemon-shaped or saccate ...... 4 Lateral field with 4 or 6 incisures. Terminal tail cuticle - Female elongate, cylindrical ...... 8 abnormally thickened. Vulva usually with epiptygma. 4. Oesophageal glands in the form of lobe, lying Spicules usually tubular. on the anterior part of intestine dorsally ...... 5 Type-genus: Merlinius Siddiqi, 1970. - Oesophageal glands in the form of lobe, lying Other genera: Prutylenchoidcs Winslow, 1958 on the anterior part of intestine ventrally ...... 6 (included in the family for the first time), 5. Female reproductive system paired, lip region Amplimerlinius Siddiqi, 1976, Geoccnurnus Thorne & of males hemispherical, oesophagus and stylet in ma- Malek, 1968, Hexudorus lvanova & Shagalina, 1983, les degenerated, gubernaculum protrusible ...... Nagelus Thorne & Malek, 1968, Scutylenchus ...... Achlysiella Hunt, Bridge & Machon, 1989 Jairajpuri, 1971. (Pratylenchidae Thorne, 1949). - Female reproductive system unpaired, lip region Family Tylenchorhynchidae of males truncated, conical, stylet and oesophagus of Eliava, 1964 males well-developed, gubernaculum non-protrusible...... Nacobbidae Chitwood in Chitwood & Diagnosis. Hoplolaimoidea. Deirid absent. Chitwood, 1950 (Nucobbus Thorne & Allen, 1944). Amphids labial, small dorso-ventral slits or pore-like. 6. Orifice of dorsal gland at the distance equal to Lateral field'with 4, rarely 3 incisures. Oesophageal the stylet length from stylet base or more ...... glands in a bulb, abutting intestine, cardia lying ...... Rotylenchulidae Husain & Khan, 1967. posterior to glands; or glands form a lobe, a dorsal - Orifice of dorsal gland at the distance shorter gland (with a large nucleus) lying at the end of a lobe. than stylet length from stylet base ...... 7 Type-genus: Tylcnchorhynchus Cobb, 19 13. 7. Excretory pore anterior to median bulb ...... Meloidogynidae Skarbilovich, 1959. The family includes only subfamilies - Excretory pore posterior to median bulb ...... Tylenchorhynchinae Eliava, 1964, Trophurinae ...... Heteroderidae Filipjev & Schuurmans Paramonov, 1967, Macrotrophurinae Fotedar & Stekhoven, 1941. Handoo, 1978 (3 subfamilies with a non-lobed 8. Oesophageal glands in a bulb abutting inte- glandular part of an oesophagus) and Telotylenchinae stine with cardia lying posterior to glands; if glands Siddiqi, 1960 (with a lobe of oesophageal glands, in form a lobe extending over intestine then the dorsal which the dorsal gland is the longest). Contents of all gland (with large nucleus) is the longest ...... these subfamilies are considered in the senseof Siddiqi ...... Tylenchorhynchidae Eliava, 1964. (1986). - Oesophageal glands forming a lobe extending over intestine, subventral glands (with small nu- Superfamily Dolichodoroidea Chitwood in Chitwood & Chitwood, cleus) are the longest ...... 9 1950 (Siddiqi, 1986) 9. Lip region low, broad, the ratio of stylet length to lip region width not more than 2.5 ...... Diagnosis. Hoplolaimina. Male caudal alae pre- ...... Pratylenchidae Thorne, 1949. phasmidial (phasmids outside the caudal alae, on the - Lip region high, narrow, the ratio of stylet tail), adanal or adanal-terminal. Lateral field of length to lip region width 3 or more ...... females and juveniles (in Neodolichodorus - in ...... Hoplolaimidae Filipjev, 1934. juveniles of early stages) does not reach the hyaline part of terminus; if it reaches, so in the form of a single Subfamily Meiodorinae Siddiqi, incisure. 1976 Type-family: Dolichodoridae Chitwood in Diagnosis: Meiodoridae. Glands in posterior bulb Chitwood & Chitwood, 1950. Other families: Psilenchidae Paramonov, 1967, abutting intestine. Male caudal alae adanal-terminal. Meiodoridae Siddiqi, 1976 (n. rank). Type-genus: Meiodorus Siddiqi, 1976. Other genera: Rruchydorus de Guiran & Germani, Key to families of Dolichodoroidea 1968, Neodolichodnr~tsAndrassy, 1976.

1. Deirid present ...... Psilenchidae Subfamily Hirschmanniellinae - Deirid absent ...... 2 Fotedar & Handoo, 1978 2. Amphid longitudinal slit-like, coming outside Diagnosis: Meiodoridae. Glands in the form of the labial zone into cephalic basis, lip region 4-lobed lobe extending over intestine. Male caudal alae adanal with prominent labial disc ...... to subterminal...... Dolichodoridae (Dolichodorus Cobb, 19 14) Type-genus: Hirschmunniella Luc el Goodey, - Amphid pore-like, on the anterior margin of 1964. labial zone, indistinct, lip region truncated, conical to No other genera. rounded, with unsignificant labial disc or without disc ...... Meiodoridae Siddiqi, 1976 (n. rank) REFERENCES

Family Dolichodoridae Chitwood in Anderson. R. V. & Townshend, J. L. 1985. A new species of root Chitwood & Chitwood, 1950 lesion nematode (Pratylenchidae: Nematoda) in Canada, with a scanr~ingelectron microscope study of its head morphology. Diagnosis: Dolichodoroidea. Amphids Carradiarr Jofrrtrol of Zoology 63: 2378-2382. longitudinal slit-like, coming outside the labial zone Andrassy, 1. 1976. Evolutiotr as a busis for tltc systettrufizaliotz of into cephalic basis, lip region 4-lobed with prominent trc~trrcltodrs.Lol~dol~, UK, Pitma11Publishir~g. 288 pp. labial disc. Male caudal alae pre-phasmidial, adanal- Aubert, V. & Luc M. 1985. Observatio~~au microscope electronique terminal, - i.e, there is a gapat the posteriorsideof ala, a balayage de Hirschrtrurrrriell spirticuudala (Sch. Stekh., 1944) (Nemnta: Pratylenchidae). Revue dc Nenratologic 8: separating terminus from bursa1 ala. 179-181. Type-genus: Dolichodorus Cobb, 19 14. Baldwin, J. G., Luc, M. & Bell, A. H. 1983. Cor~tributionto thestudy No other genera. of the ge~~usProtyl~rrclroidc~s Wit~slow (Nematoda: The monotypic group, differing from other Tylenchid;~). K~vrrc.dc N~~trrcitologic~6: 1 1 1 - 125. families by shape of lip region and amphidial aperture Bridge, J., Mortimer, J. J. & Jackson, G. V. H. 1983. form. Hirschrrrurrrrit~llur~riticorrsu r~.sp. (Nematod;~: Pratylenchidae) and its pathoge~~ecityon taro (Colocasi:~escule~~ta). Revutp de Family Meiodoridae Siddiqi, 1976 Nct~rutologie6: 285-290. (n.rank) Chitwood, B. G. & Chilwood, M. B. 1950. At1 lrrtroductiorr to Ncrtrutology. Baltimore, Mor~umcr~talPrint Co. 21 3 pp. Diagnosis: Dolichodoroidea. Amphid pore-like, Chizhov, V. N. & Berezina, N. V. 1988.IStructure and evolution of on the anterior margin of labial zone, lip region the female ger~italsystcm of nematodes of the order Tylenchida (Nematoda). 2. Primary didelphic species). Zoologichtsky truncated, conical to rounded, with insignificant labial Zlrurrru167: 485-494. disc or without disc. Male caudal alae pre-phasmidial: Chizhov, V. N. & Kruchina, S. N. 1988. IPhyloget~yof thenematode adanal, adanal-terminal, subterminal. order Tylenchida (Nematoda) I. Zoologich~~skyZhurtrul 67: Type-subfamily: Meiodorinae Siddiqi, 1976 1282-1 293. Other subfamily: Hirschmanniellinae Fotedar & Chizhov, V. N. & Kruchina, S. N. 1992. [The systematics of thc Handoo, 1978 nematode order Tylet~chida (Nematoda) 1. Zoofogicl~esky Phylogeny of Tylenchida

Zhurna17 1: 5- 1 6. Ryss, A. Y. 1981. [Morphoge~lzsisof the female genital system in the Doucel, M. E. 1985. A new species of Meiodorus Siddiqi, 1976 superfamily Tylerlchoidea (Nematoda) 1. Parozito/ogiya 15: (Nematoda: Tylenchida) from Cordoba, Argerltilia. Revue de 533-542. Norrofologie 8: 53-57. Ryss, A. Y. 1987. [Types of the parasitism of the plant nematodesand Drozdovsky, E. M. 1989. [On theclassificatioli of theclassNematoda the problem of all evolution of the superfamilies Tylenchoidea to thesubclasses level and on the phyloger~eticrelations between and Hoplolaimoidea (Tylenchida)] . Parazifologiclreskij some Nematoda taxa belonging to the Chromadoria line of sbornik, Zoologicallrrstitute of the USSR Acuderny of Sciertces evolution]. Proceeditrgs of tlreZoological Itrstituteof the USSR 34: 169-191. Acaderny of Sciences 194: 39-59. Ryss, A. Y. 1988. [Root Parasitic Notratodcs of the Fartlily Filipjev, I.N. 1934. The classificutiotr of tlrefi-ee-livirrg rretr~atodes Pratylerrclrid~~i~(Tyletrchido)of the World Fautra] . Leningrad. and their relatiorr to the parasitic ttcrtrotodes. Smithsoniati Nauka. 368 pp. Ilistitution, 8 pl, 63 pp. Ryss, A. & Krall, E. 1981. Classification of the superfamilies -Filipjev. I. N. 1936. Ueber freilebetide und pfla~~ze~iparasitische Tyle~~choideaand Hoplolaimoidea with notes on the phylogeny Gatturigen der Tylenchinen. Travoux de fItrstitrct Zoologiquc, of the suborder Tylenchilia (Nematoda). Procerditrgs of the rle PAcodemie des Sciertces dc, f URSS 3: 537-550. Acodetrty of Scic,rrcts of tire Estoniort Republik. Diologia 30: Fortuncr, R., Geraert. E.. Luc, M., Maggenti, A.R. & Raski, D. J. 288-298. 1987-1988 (Contributors). A reappraisal of Tylet~china Seinhorst, J. M. 1971. The structure of the glandular part of the (Nemata). Extraits de: Revue de Nernatologie 1987, 10: 127- oesophagus of Tyletlchida. Nettrutologica 17: 43 1-443. 232 (parts 1-8), 10: 409-444 (part 10); 1988, 1 1 : 159-1 88 Sher, S. A. & Bell, A. H. 1975. Scarl~li~~gelectrotl micrographsof the (parts 9, 1 I). anterior region of some species of Tylerlchoidea (Tylenchida: Gcraert. E. & Raski, D. J. 1987. A reappraisal of Tylenchina Nematoda) . Jourtrul o/Nerrra!ology 7: 69-83. (Nemata;. 3. The family Tylenchidae Orley, 1880. Revlcc. de Siddiqi, M. R. 1971. Structure of the oesophagus in the classification Nenratologie 10: 1 43- 1 6 1. of the stlperfamily Tyle~~choidea(Nematoda). in dint^ Journal Lorenzen, S. 1981. Entwurf eines pbyloger~etischen Systems der of Nettrutology 1 : 25-43. freileber~denNematoden. Veroffentlichurrgerr des Irutituts /lrr Siddiqi, M. R. 1978. The unusual positiorl of the phasmids in Mc~eresforsckung in Brerrrerl~uvetr, Suppleme111 17. Coslettchus costutus (De Mali. 1921) get]. n., comb. n. and Komissio~isverlagFraliz Leuwer. Bremen, 472 S. other Tylerlchidae (Nematoda: Tyle~ich~da).Nentutologica 24: Luc, M. & Fortuner, R. 1987. A reappraisal of Tylenchinn 449-455. (Nemata) .5. The family Dolichodoridae Chitwood et Chitwood, Siddiqi, M. R. 1980. The origin and phylogerly of the nematode 1950. Revue de Nerrratologie 10: 177- 18 I. orders Tylerichida Thorne, 1949 and Aphelenchida n. ord. Maggenti, A.R. 1971. Nemic relationships and the origirls of plant Hebrrirrtlrological Abstract, Ser. B. 49: 143- 170. parasitic nematodes. In: Plartt Parasitic Ncrtrcltodes. (M. Siddiqi. M. R. 1986. Tyli~rrclridu:Parusites of Plattts ntrd Insects. Zucherman, W.F. Mai & R. A. Rohde. Eds.) pp. 65-81. New Serit Albans, Commoliwealth Agricultural Oureaux. 645 pp. York, London, Academic Press. Skarbilovich, T. S. 1978. [A short classification of high taxa of the Maggenti, A. R. 1981. General Nettralology. New York, Heidelberg, nematodes from the order Tyle~ichida Thorne, 19491. Berlin, Springer Verlag. 372 pp. Byulletetr' Vsesoyuzt~o~oltrstituto Gcfrtrintologii 23: 31 -35. Paramonov, A. A. 1962. [Principlts of the Pltytolrelrtritrtl~ology]. Skarbilovich. T. S. 1980. [A short taxo~lomicsystem of families, Vol.l., Moscow, Nauka. 480 pp. subfamilies and genera with type speciesof the nematodes in the Paramonov. A. A. 1970. [Prittciples of tl~ePlrytohrlrtrirrtlrology]. order Tyle~ichidaThor~ie, 19491. Byullet~~t~'Vsesoyuznogo Vol. 3. Moscow, Nauka. 256 pp. Irrstitutu Geftrritrtologii 26: 66-79. Raski. D. J. & Maggenti, A. R. 1983. Tylenchidae: Morphological Sumenkova, N. 1. 1984. [Colilemporary views or1 the origiri arld diversity in a natural evolutionary group. In: Corrcepts itr evolutiori of the nematodes of the order Tylenchida]. Itogi Nernatode Systenratics. (A. R. Stone, H. M. Platt & L. F. Nauki i Telrtliki. Moscow, VINITI 4: 5-27. Khalil. Eds.) pp. 13 1-1 42. London, Academic Press. Yuen, P. H. 1966. Further observaliolis on NelicotyCtrchus vr~lgc~ris Roman, J. & Hirschmann. H. 1969. Embryogenesis and Yuen. Nrrrrafologicu 1 1 : 623-637. postembryogenesis in species of Pratylencl~us (Nematoda: Zuckerman, B. M. & Slrich-Harari, D. 1963. The life stages of Tylenchidae). Proceedirrgs of tlrc Helttrir~thologicalSociety of HelicotyLtichus trrrtlticitrctus (Cobb) ill banana roots. Washittgtott 36: 164- 174. Nettuitologicu 9: 347-353 A. Ryss

P~ICCA.m. @nnore~unHeMaTon o-rpnna Tylenchida (Nernatoda). Pesloue. CTPYKT~~LI,~a~6onee BaxHble mu MaKpoTaKcotioMnn Knncca Nernatoda: a~@b~n,@an~un, nefipnn, 6oaosoe none, OKO~O~OTOBO~~KOMflneKC CeHCMnJl - PaCnOnOXeHbl Ha ~OKOB~IXJlyKlaX Tens MnM s6nn3u 0T HWX. npemarae~cupaccMarpneaTb wx KaK enuHylo cnoxHylo c~py~rypyu npMcnobtTb eil ~asoa~neuna~epanbtlb18 KOMnneKC*. K naTepanbHoMy KOMIlneKCy Tylenchida OTHOCUTCSI M 6ypca CaMUOB, KOTOpau MOXeT 6blTb ~~c@~DMM- n~anbH0fi(Ha XBOCTe OTCYTCTBYIOT (bil3MM~bl).npen@a3MMnManbt!ofi (6ypcanbHble Kpblnbfl ptlCflOnoXeHbl Ilepen @as~nna~n)u @a3~nnuanb~ofi (@an~nnb~ pacnonoxetibl Ha 6ypcanb~blxKpblnbnx u Rune 6yp~anbHbl~pe6ep. 6ypca oxeaTbrsaeT XBOCT).@unore~na oTpana Tylenchida npoatianu~upoaa~anyTeM cpaeHeHnn naTepanbHblx KOMflneKCOB. He~aTonblPOna Atetylencl~usCnenyeT PaCCMaTpclBaTb KaK ~an6oneenpnMtITnRHble. Han6onee 6nu3~a K ~CT~CTB~HHO~~CMCTeMil HeMaTOn, flpeWOXeHHan Siddiqi (1986). B paMKaX OTpuna Tyler~chidapa:CMZlTpMBaIOTCfl 4 nonoTpnna, u3 KOTOP~IX TPM: Tylenchina, Criconematina, Hexatylina 06nanalo.r KoMnneKcaMn cn~ano~op@uil (MOHO@W~~TM'IH~I),a Hoplolairnina npencTaanner co6ofi napa@une~u~~ec~ufiocTa-roK TaKcoHoMuvecKoro rpynnuposaHnn o-rpwna. Hoplolaimina BKnlotlaeTnea Han~eMefi~TUa:Dolichodoroidea (Psilenchidae, Meiodoridae n. rank.: Meiodorus, Rraclrydorus, Neodolicl~odorus, Hirscl~rrrut~niella,Dolichodoridae: Dolichodorus) n Hoplolaimoidea (Merliniidae n. rank.. BKnmllamuee Prutyletzcl~oides, Belonolaimidae, cooTseTcroyloqee Belonolaiminae sensu Siddiqi, 1986, Tyle~~chorhynchidae,Hoplolaimidae u npyrne ce~efic~naB~ICLIJMX @TO- napa3u~os).floplolairnoidea ornnxlae-rca OT Dolichodoroidea oxoa~b~oa~ouefixeoc~ @an~wnc1anb~oil6ypcofi caMqos M nOCTWratOqWM ~M~~MHOBO~(30HbI XBOCTa ~OKOB~IMnOneM nMWlHOK M CaMOK (y Dolichodoroidea 6ypca npen@a3~nnnanb~an,6o~osoe none He nocTnraeT IWI~MHOBO~~~OH~IXBOCTB). Psilenchidne npencraenneT coboil llapa@~neT~4e~~ylOrpynny, He 06'be~M~~e~yloCMHB~~OMOP@MWMM, KYAa OTHOCHTC%l ~au6oneeIlPMMHTHBHble Tylenchida. uKnloqaa Atetylcrlchus. npenc~aone~K~IO~I mu onpeneneclnu nonoTpanou, a TaKxe ~ance~efic~on nonce~eAc~snonoTpnna Hoplolaimina.