SHORT COMMUNICATION 350 Acta Zoologica Lituanica, 2003, Volumen 13, Numerus 3 ISSN 1392-1657 A REAPPRAISAL OF SCUTELLONEMA PICEA GUBINA, 1973 (NEMATĄ: HOPLOLAIMIDAE FILIP'EV, 1934) INTO ROTYLENCHUS ROBUSTUS (DE MAN, 1876) FILIP'EV, 1936 AND THE CORRECTION OF THE LITHUANIAN LIST OF NEMATODES Andrius STANEL1S Lithuanian State Plant Protection Service, Pelesos 85, 2014 Vilnius, Lithuania. E-mail: [email protected] Gubina (1973) found Scutellonema picea in Juodkrantė nursery of forest trees and described them as a new spe- cies. She did not use a scanning electronic microscope. Šlepetienė (1986) pointed out this species as new for the Lithuanian list of nematodes, but her record is in- correct. Fortuner (1985, 1987) reviewed these nema- todes and determined that the Scutellonema picea Gubina, 1973 is the same species as Rotylenchus robustus (de Man, 1876) Filip'ev, 1936. The name Scutellonema picea is left as the synonym for Rotv- lenchus robustus. The hoplolaimids were first proposed as a separate taxon by Filip'ev, 1934 (Fortuner 1987). At that time, the nominal genus, Hoplolaimus, included some species that now belong to the criconematids. Filip'ev included a number of criconematid genera (Paratylenchus, Iota=Ogma, Criconema, Procriconema=Hemicyclio- phora) in the new subfamily Hoplolaiminae. After the arrangement of the criconematids as a sepa- rate subfamily by the nematologists (Taylor 1936; Thome 1949), the genera Hoplolaimus, Rotylenchus, and Helicotylenchus were left in the Hoplolaimidae, and they are still accepted today as the most typical representatives of the family. The Thorneian concept of hoplolaimids was accepted by all later authors. The contribution of the more re- cent classifications consisted mostly of the addition of newly described genera and the arrangement of recog- nized genera under various subfamilies. The increase in number of subfamilies (seven subfamilies for eleven valid genera) raised some doubts about the necessity of creating taxa of higher rank. The taxonomic posi- tion of some genera (Rotylenchus, Acontylus) is still unsettled. Scutellonema is close to Rotylenchus as it is seen from the size, general appearance and the arrangement of Figure I. Phasmides of nematodes: (a) Scutellonema cavanessi scutella, (b) pore-like Rotylenchus fallorobustus. the esophageal glands. There are some slight differ- Photo (a, b) is made by LM DIC system and photo (c) is ences between the two genera (Table 1). made by SEM. For example, Scutellonema has lateral field generally 351 A reappraisal of Scutellonema picea Gubina, 1973 Table I. Diagnosis of the genera Rotylenchus Filip'ev, 1936 and Scutellonema Andrassy, 1958 (after Fortuner 1987). Rotylenchus Scutellonema Female: Body spiral to C-shaped. Female: Body spiral to C-shapcd or almost straight. Labial region offset or continuous with body contours, Labial region narrow truncate to offset rounded; annulated, anteriorly rounded or flattened, generally annulated, with or with or without longitudinal striae. First labial annulus divided without longitudinal striae on basal lip annulus. into six sectors, lateral sectors smaller than the others (SEM). Amphid apertures oval between labial disc and lateral sectors. Lateral field with four lines, with or without scattered Lateral field with four lines usually areolated near phasmids transverse striae. and anteriorly, sometimes transverse striae scattered over whole field. Labial framework, stylet, and stylet knobs average sized for Labial framework, stylet and stylet knobs average sized for the family; knobs with rounded to indented anterior surface. the family; knobs rounded to indented. DGO often close to stylet (6 µm) but with a tendency to DGO 4-8 µrn from stylet base. posteriorly directed migration (up to 16 µm). Esophagcal glands overlap intestine dorsally and laterally; Esophageal gland overlap dorsal and lateral. dorsal gland more developed than subventral glands; intestine symmetrically arranged between the subventral glands. Two genital branches outstretched, equally developed; Two genital branches outstretched, equally developed. posterior branch rarely degenerated. Epiptygma single or double present. Epiptygma present. Tail short, hemispherical, rarely with small ventral projection; Tail short, rounded; phasmids enlarged (scutella) situated phasmids pore-like, small, near anus level. opposite each other, near anus level. Male: Caudal alae enveloping tail, not lobed. Male: Caudal alae enveloping tail tip, regular or rarely deeply lobed. Secondary sexual dimorphism not marked, sometimes No secondary sexual dimorphism. anterior part of male body slightly smaller than female. areolated at phasmids and anteriorly. However the pri- that Scutellonema picea Gubina, 1973 is the same spe- mary difference between the two genera is the size of cies as Rotylenchus robustus (de Man, 1876) Filip'ev, the phasmids enlarged to scutella in Scutellonema, and 1936. The name Scutellonema picea is left as the syn- pore-like phasmids in Rotylenchus. In this aspect, onym for Rotylenchus robustus. Scutellonema is intermediate between Rotylenchus with It happened after the review of the whole Hoplolaimi- pore-like, adanal phasmids and Hoplolaimus, where nae with other species in Rotylenchus genera. The list the migration of the scutella anteriorly to anus is often of those type species is presented below: accompanied by the evolution of other characters. It is impossible to identify Hoplolaiminae exactly with- Rotylenchus robustus (de Man, 1876) Filip'ev, 1936 out using SEM (scanning electronic microscope). A = Scutellonema picea Gubina, 1973 light microscope with Nemarski DIC system is used = Hoplolaimus uniformis Thorne, 1979 for the detection of pore-like or scutella structure in R. impar (Phillips, 1971) Germani, Baldwin, Bell & nematodes (Fig. 1). Gubina (1973) made a mistake when Wu, 1986 she found Scutellonema picea in Juodkrantė nursery of = Scutellonema impar Phillips, 1971 forest trees and described them as a new species. She R. incisicaudatus (Phillips, 1971) Germani, Baldwin, did not use a scanning electronic microscope. Šlepetienė Bell & Wu, 1986 (1986) pointed out this species as new for the Lithuanian = Scutellonema incisicaudatus Phillips, 1971 list of nematodes, but her record is incorrect. Fortuner R. indorobustus Jairajpuri & Baqri, 1973 (1985, 1987) reviewed these nematodes and determined = Scutellonema petersi Mahajan, 1977 352 Stanelis A. R. insularis (Phillips, 1971) Germani, Baldwin, Bell & Nickle, W.R. 1991. Manual of Agricultural Nematology. Wu, 1986 New York, USA: Marcel Dekker. = Scutellonema insulare Phillips, 1971 Siddiqi, M.R. 2000. Tylenchida: parasites of plants and R. leviflexus (Phillips, 1971) Germani, Baldwin, Bell insects. London, UK: CAB International. & Wu, 1986 Šlepetienė, J. 1986. The anthropogenic effect on soil and = Scutellonema leviflexus Phillips, 1971 plant nematodes. Vilnius: Mokslas. R. minutus (Sher, 1964) Germani, Baldwin, Bell & Wu, Taylor, A.L. 1936. The genera and species of the 1986 Criconematinae, a subfamily of the Anguillulinidae = Scutellonema minutum Sher, 1964 (Nematoda). Transactions of American Microscopy Society 55: 391- 421. The whole list of Rotylenchus contains 63 species Thome, G. 1949: On the classification of the Tylenchida, (Siddiqi 2000). R. robustus is widely distributed in new order (Nemata: Plasmidia). Proceedings of the Europe, Russia, Egypt, Zaire, India, Canada, USA, and Helminthological Society Washington 16: 37-73. Brazil. R. robustus is only one species from the Rotylenchus genus recorded in Lithuania (Šlepetienė 1986). It prefers light sandy soil and it parasitizes in PATAISYMAS LIETUVOS NEMATŲ SĄRAŠE: SCUTELLO- many grasses, ornamentals, vegetable crops, and for- NEMA PICEA GUBINA, 1973 (NEMATA: HOPLOLAI- est trees. This nematode is an ectoparasite of roots caus- MIDAE FILIP'EV, 1934) YRA ROTYLENCHUS ROBUS- ing reduced growth, yellowing, and yield reduction TUS (DE MAN, 1876) FILIP'EV, 1936 SINONIMAS (Nickle 1991). There are 49 species in the genus Scutellonema (Siddiqi A. Stanelis 2000). Almost all these species are distributed in trop- ics. Scutellonema species parasitizes in many grasses, SANTRAUKA ornamentals, vegetable crops, and forest trees. Pateikiami duomenys apie sunkiausiai morfologiškai identifikuojamas Scutellonema ir Rotylenchus nematų REFERENCES gentis iš Hoplolaiminae šeimos. V. Gubina Juodkrantėje aptiko nematą ir 1973 metais aprašė jį kaip naują rūšį Gubina,V.G. 1973. Scutellonema picea n. sp. (Nematoda: Scutellonema picea. Ši rūšis 1986 J. Šlepetienės buvo Hoplolaimidae) and a new variety of Paratylenchus įtraukta į Lietuvoje registruotų nematų sąrašą. R. For- nanus Cobb, 1923 (Nematoda: Tylenchidae) from roots tuner 1985 ir 1987 metais peržiūrėjo šiuos nematus ir and rhizosphcrc of conifer seedlings. Works of the nustatė, kad Scutellonema picea turi būti sinomizuotas helminthological laboratory 23: 52-55 (in Russian). su Rotylenchus robustus (Fortuner 1987). J. Šlepetienės Fortuner, R. 1985. Notes on nomenclature of plant nema- sudarytame nematų sąraše Rotylenchus robustus ir todes. Revue Nematology 8(1): 77-83. Scutellonema picea pateikiamos kaip atskiros rūšys. Fortuner, R. 1987. A reappraisal of Tylenchina (Nemata). The family Hoplolaimidae Filip'cv, 1934. Revue Received: 6 February 2003 Nemalology 10 (2): 219-232. Accepted: 25 September 2003 Kompiuteriu rinko ir korektūras skaitė B. Jankauskienė. Viršelis ir maketas G. Vaitonio. Vertė L. Monkienė, O. Stokys, A. Tamošiūnienė, R. Anusevičienė. 2003 09 25. Formatas 60x90/8.