Journal of Nematology 44(4):399–426. 2012. Ó The Society of Nematologists 2012. Taxonomic and Molecular Identification of Mesocriconema and Criconemoides Species (Nematoda: Criconematidae) 1 1 2 MARCO A. CORDERO, ROBERT T. R OBBINS, ALLEN L. SZALANSKI Abstract: Populations of Mesocriconema curvatum, M. kirjanovae, M. onoense, M. ornatum, M. sphaerocephala, M. surinamense, M. vadense, M. xenoplax, and Criconemoides informis from different geographical areas in the continental United States were characterized mor- phologically and molecularly. A new ring nematode from Washington County, Arkansas, is also described and named Mesocriconema ozarkiense n. sp., This new species is characterized by females with small flattened submedian lobes, lower than or at the same level as the labial disc, vagina straight, very well developed spermatheca without sperm, no more than one anastomoses, L=379-512 mm, V=89- 93, stylet length = 49-61 mm, R=107-119, annuli with slightly crenate margins on tail portion and a simple anterior vulval lip. The molecular characterization of M. ozarkiense n. sp. using the ITS rRNA gene sequence and the phylogenesis relationship of this new species with the ring nematodes included in this study are provided. Key words: Criconematidae, Criconemoides, Criconemoides informis, internal transcribed spacer 1, Mesocriconema, Mesocriconema ozar- kiense n. sp. M. crenatum, M. curvatum, M. kirjanovae, M. onoense, M. ornatum, M. sphaerocephala, M. surinamense, M. vadense, M. xenoplax, molecular biology, morphology, phylogenesis, taxon. Ring nematodes of the genera Criconemoides Taylor crenate; first annulus seldom separated; the four sub- 1936 and Mesocriconema Andrassy, 1965 are damaging median lips are reduced and showing each a prominent root ectoparasites of many economical important crops. outgrowth or true submedian lobes; an open vulva with Proper identification of these nematodes is critical for often ornamented anterior lip; postvulval body short their management and development of germplasm re- with terminus round or truncate. sistant to these pests. Morphological studies concerning Criconemoides and The taxonomic status of the genera Criconemoides Mesocriconema species are numerous in the literature, Tylor 1936 and Mesocriconema Andrassy, 1965 is contro- but data on the molecular characterization of these ring versial and taxonomists have not reached a consensus nematodes is insufficient and necessary in order to of opinion about the validity and species composition validate their taxonomic status and infer phylognetic of these genera. Many taxonomists including Brezski relationships among the species of these genera. Mo- et al. (2002 a,b) consider these two genera valid, how- lecular information derived from the high variable, ever, others, such as Siddiqi (2000), list Mesoscriconema D2-D3 expansion segment of the 28s rRNA gene of re- as a junior synonym of Macroposthonia de Man, 1880. In presentatives of Criconematina was recently provided a recent classification of plant parasitic nematodes by by Subbotin et al. (2005) based on the classification of Decraemer and Hunt (2006) the genus Mesocriconema is Siddiqi (2000). The results of their phylogenetic anal- synonymized with Criconemoides. In this paper, we follow ysis based on D2-D3 domain indicated monophyly the classification proposed by Brzeski et al. (2002 a,b). among Mesocriconema, Hemicriconemoides, and Criconema According to these authors the species of the genus and showed that a representative of the genus Criconemoides Criconemoides are characterized morphologically by an- clustered together with Mesocriconema species. The nu- nuli more or less retrorse, first and second annuli sepa- clear rDNA internal transcriber regions (ITS) have been rated from succeeding annuli, presence of six pseudolips used as markers because its low intraspecific variation on the first annulus, consisting of two lateral ones re- for species identification in several nematodes, repre- duced to a connection with the four more developed senting useful information in order to develop tools and pronounced submedian lips; a closed vulva with for diagnostic purposes based on PCR reactions (Gasser, a non-ornamented anterior lip; postvulval body short, 2001). In a recent study by Powers et al. 2010, sequences conoid with a terminus rounded, conoid or acute. The of the nuclear ribosomal ITS1 were obtained for M. species of the genus Mesocriconema are characterized by curvatum (Raski, 1952) Loof & De Grisse, 1989, M. a cuticle with retrorse annuli with margin smooth or rusticum (Micoletzky, 1915) Loof & De Grisse, 1989 and M. xenoplax (Raski, 1952) Loof & de Grisse, 1989. Received for publication May 15, 2012. The major objectives of this study were: i) to integrate 1Graduate assistant and University Professor, Department of Plant Pathology, the morphological and morphometrical characteriza- Cralley/Warren Research Lab., 2601 N. Young Ave., University of Arkansas, Fayetteville, AR 72704. tion of populations of known Mesocriconema and Crico- 2Professor, Department of Entomology, 319 Agriculture Bldg. University of nemoides species in the continental United States and Arkansas, Fayetteville, AR 72701. The authors thank Keith Striegler, University of Missouri; Weimen Ye, North describe a new species namely, Mesocriconema ozarkiense Carolina Department of Agriculture; Tim Todd, Kansas State University; Ernest n. sp.: ii) to characterize molecularly M. ozarkiense and Bernard, University of Tennessee and Howard Ferris, University of California- Davis for providing specimens for this study and Mourad Benamara, Institute other ring nematodes included in this study using for Nanoscience and Engineering, University of Arkansas, Fayetteville for his ITS1 rRNA gene; and iii) reconstruct the phylogenetic support with the scanning electron microscope. E-mail: [email protected] positionofthesespeciesintheCriconematinaeusing This paper was edited by Zafar Handoo. the analysis of this gene. This is the first part of four 399 400 Journal of Nematology, Volume 44, No. 4, December 2012 TABLE 1. Measurements and ratios of Mesocriconema ozarkiense n.sp. Morphometrics of related species are presented for comparison. Mean, standard deviation and range in mm. M. ozarkiense M. ozarkiense M. M. M. M. M. M. M. M. Character/Ratio Holotype1 (n=19) Paratypes1 citricolaa denoudenia jessiensea ornicaudaa paradenoudenia parareedia reedia sigillariuma L 412.12 424.9 6 38.9(378.8-512.1) 380-470 390-570 440-560 370-460 320-470 380-480 360-470 370-450 Oesophagus length 93.38 94.0 6 6.9(81.2-111.7) - - - - - - - - Tail 27.61 24.7 6 3.1(18.7-30.0) - - - - - - - - Maximum Body width 43.04 41.8 6 2.8(36.5-48.7) - - - - - - - - a 9.58 10.2 6 0.9(8.4-11.9) - - - - - - - - b 4.41 4.5 6 0.2(4.2-4.9) - - - - - - - - c 14.93 17.4 6 2.2(13.2-22.5) - - - - - - - - Distance lip region to vulva 370.71 388.2 6 37.8(340.6-475.6) - - - - - - - - Distance lip region to anus 384.51 400.2 6 37.9(353.6-483.7) - - - - - - - - V 89.95 91.3 6 1.0(88.7-92.9) 90-92 90-94 90-93 88-93 90-94 88-90 90-92 87-90 V’ 96.41 97.0 6 0.6(96.0-98.3) - - - - - - - - Distance lip region to end 97.44 98.4 6 7.7(87.3-121.8) - - - - - - - - oesophageal gland Body width at anus 25.17 23.2 6 2.1(20.3-27.6) - - - - - - - - b’ 4.23 4.3 6 0.2(4.0-4.7) - - - - - - - - c’ 1.10 1.1 6 0.1(0.9-1.2) - - - - - - - - Distance between vulva & post 41.41 36.6 6 3.8(30.0-44.7) - - - - - - - - end of body Body width at vulva 31.67 29.7 6 2.1(26.0-34.1) - - - - - - - - VL/VB 1.31 1.2 6 0.1(1.0-1.4) 1.1-1.4 1.0-1.3 0.8-1.1 1.1-1.6 0.8-1.4 1.3-1.6 1.1-1.3 1.3-1.6 Rex 29.00 29.2 6 1.6(27.0-34.0) 23-26 32-37 22-26 24-33 38-35 31-34 26-29 35-39 Roes 30.00 29.2 6 1.4(26.0-31.0) - - - - Rvan 3.00 2.9 6 0.5(2.0-4.0) 2-3 0-2 1-2 1-2 2-4 - 1-3 5-7 Ran 8.00 7.2 6 0.8(6.0-10.0) 4-5 6-9 6-7 6-9 4-7 3-5 5-7 5-9 RV 12.00 11.1 6 1.0(10.0-14.0) 8-9 8-11 8-9 9-11 8-10 12-13 9-10 11-15 R 114.00 111.6 6 3.1(107.0-119.0) 73-78 102-127 88-102 92-111 102-130 111-121 104-112 115-127 Stylet length 58.87 55.4 6 3.1(48.7-60.9) 48-51 53-59 56-61 43-50 39-52 59-66 51-62 46-51 Length of stylet shaft 14.21 14.0 6 1.0(12.2-16.2) - - - - - - - - m 75.86 74.8 6 1.3(72.6-77.3) - - - - - - - - Stylet length as percentage 14.28 13.1 6 1.0(11.2-14.9) - - - - - - - - of body length Distance between stylet 0.81 2.1 6 0.8(0.8-4.1) - - - - - - - - base and D.O.G O 1.38 3.8 6 1.6(1.4-8.1) - - - - - - - - Distance lip region-centre 62.93 67.1 6 4.5(62.9-81.2) - - - - - - - - median bulb MB 67.39 71.5 6 4.0(59.6-77.5) - - - - - - - - 1. Host: Paspalum spp. a (Brzeski et al., 2002a). Identification of Species of Mesocriconema and Criconemoides: Cordero et al. 401 intended to clarify and identify species of the super- Additional populations of nematodes were obtained family Criconematoidea following the classification from California, Kansas, Missouri, North Carolina and of Brzeski et al. (2002 a,b) and Raski and Luc (1987).