Redescription of Three Ektaphelenchus Species (Nematoda: Aphelenchina)

Three Ektaphelenchus species with unusual spicules are redescribed. Ektaphelenchus obtusus and E. riograndensis are redescribed from newly discovered material in the collection of the USDA Forest Service RMRS. Lectotype slides are designated for both species. Ektaphelenchus obtusus is characterized by a set-off head, lips of unequal size, double rows of oocytes and spermatocytes, and a hooked spicule terminus. Ektaphelenchus riograndensis is distinguished by a rounded head with six equal lips, and spicules with a large, rounded apex, and recurved terminus. A bursa and gubernaculum are absent in both species. Ektaphelenchus scolyti is redescribed from type material deposited in the collection of Rothamsted Experimental Station. It is characterized by a well set-off head, double rows of oocytes and spermatocytes, and spicules with a hooked terminus. A bursa and gubernaculum are absent.     

Aphelenchoides microstylus n. sp. and Seinura onondagensis n. sp. (Nemata: Aphelenchina) from New York

Aphelenchoides microstylus n. sp. and Seinura onondagensis n. sp., a nematode predator, are described from dead Scots pine (Pinus sylvestris L.) in Onondaga County, New York. Females of A. microstylus are 370 to 485 µm long. The body is slender and tapers posteriorly to an amucronate, pointed terminus. The head is continuous with the body, and lips bear a stylet guide. Diagnostic characters of females are three incisures in the lateral field, a short stylet (6-7.5 µm) with small basal knobs, a single row of oocytes, and a long postuterine sac (25-50 µm). Males are characterized by small spicules (10-11µm); two pairs of post-anal, subventral papillae; and a single row of spermatocytes. A bursa and gubernaculum are absent. Seinura onondagensis females are characterized by a body of moderate length (475-595 µm), finely annulated cuticle, and a slightly set-off head. Diagnostic characters are four incisures in the lateral field, long stylet without basal knobs (17-22 µm), single row of oocytes, and presence of a postuterine sac (14-38 µm). Males are unknown. The monospecific genus Indaphelenchus is proposed as a synonym of Seinura, and S. siddiqii n. comb. is proposed for the only species, I. siddiqii.     

Description of Non-Type Seinura winchesi from Mushroom Compost (Nematoda: Seinuridae)

Non-type material identified as Seinura winchesi, and deposited in the collection of the Nematology Department, Rothamsted Experimental Station, England, is described. The material was collected from mushroom compost in Leeds, England, in 1957. Females of this population are characterized by a set-off head, knobless stylet (20-21 µm), two rows of oogonia-oocytes, and absence of a postuterine sac. The median bulb is oblong and, at times, is constricted in the middle. The body is 565 to 675 µm long and tapers posteriorly to a pointed terminus. The cuticle is finely annulated, and there are three incisures in the lateral field. The ovary is outstretched and overlaps the esophageal gland lobes. A spermatheca is present, and spermatozoa are visible. The vulva is posteriorly located (V = 77-80), and a flap is absent. Males are 550 to 680 µm long with a spicate tail that bears three pairs of subventral papillae. The spike is short (14-18 µm), about one-half the tail length. The testis is 360 to 412 µm long, not reflexed, and at times overlaps the esophageal gland lobes. Spermatogonia-spermatocytes are in two rows. Spicules are 14 to 15 µm long with a prominent apex, and small rostrum. A bursa and gubernaculum are absent.     

Mesocriconema kirjanovae (Nematoda: Criconematidae) from Southeastern Spain

An abundant female population of a criconematid species identified as Mesocriconema kirjanovae (Andr ssy, 1962) Loof &De Grisse, 1989 is reported from a natural habitat in southeastern Spain. Measurements and morpho-anatomy obtained with light microscopy and scanning electron microscopy are included and compared with previous data on this species.     

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda) Parasitizing Aedes albifasciatus Mac. (Culicidae: Diptera) in Argentina

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda), a parasite of the mosquito Aedes albifasciatus Mac. in Argentina, is described. Diagnostic characters of this species include a ventrally shifted mouth opening and spicules fused at the tips. The mermithid has been reared on Culex pipiens L. larvae in the laboratory.     

A New Species and New Combinations of Brevitobrilus Tsalolikhin, 1981 (Nematoda: Tobrilidae) from Spain

A new species of Brevitobrilus Tsalolikhin, Brevitobrilus montanus n. sp., found in high mountain lakes and rivers in Granada, Spain, is described. Additional data on Brevitobrilus granatensis (Ocafia &Zullini, 1988) n. comb. are provided. Brevitobrilus raontanus n. sp. is characterized by moderate size (1.3-1.8 mm), amphid aperture width one-quarter the head width, subterminal seta distance from terminus four times the width of the terminal end of the tail, and supplements S5 and S6 separated. Tobrilus granatensis Ocafia &Zullini, 1988; Tobrilus sardus Vinciguerra &Zullini, 1991; and Tobrilus siculus Vinciguerra &Zullini, 1991 are all transferred to Brevitobrilus. Differences among the 13 species of Brevitobrilus are discussed.     

Taxonomic and Molecular Identification of Mesocriconema and Criconemoides Species (Nematoda: Criconematidae)

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 morphologically 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 μm, V=89-93, stylet length = 49-61 μm, 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.     

Taxonomic Notes on Four Species of Panagrellus Thorne (Nematoda: Cephalobidae)

Four populations of Panagrellus redivivus (Linnaeus, 1767) Goodey, 1945, and syntypes of P. dubius Sanwal, 1960, P. redivivoides (Goodey, 1943) Goodey, 1945, P. pycnus Thorne, 1938, P. zymosiphilus (Brunold, 1950) Brunold, 1954, and P. leucocephalus Steiner, 1936 were examined. Additional information on the morphology of spicules and stoma is presented. P. zymosiphilus is synonymized with P. redivivoides and Rühm''s synonymization of P. silusiae and P. leucocephalus with P. redivivus is supported. Lectolypes for P. pycnus and P. redivivoides are designated.     

Further Details and SEM Observations on Meloidogyne marylandi (Nematoda: Meloidogynidae)

Specimens of Meloidogyne marylandi from Bermuda grass and a population from Zoysia grass were examined and compared morphologically by light and electron microscopy. The populations probably are conspecific and the differences noted in the Zoysia population, mainly those of second-stage juveniles (J2) with shorter tails, are considered normal variations rather than representing another form. Scanning electron microscope observations provided additional details of the perineal pattern and head of females and head and lateral fields of second-stage juveniles. Relationship of M. marylandi to closely related species is given. This species is currently known to occur only in Maryland, and populations previously reported from this state as M. graminis are now considered to be M. marylandi. Other reports of M. graminis in the United States now need to be reconfirmed by examination of voucher or recollected specimens.     

Criconemella anastomoides n. sp. (Nematoda: Criconematina) from Pakistan

Criconemella anastomoides, described and illustrated herein, is characterized by the presence of regular anastomosis on the body, two zig zag lateral lines, stylet knobs sloping posteriorly, short stylet, and short body length.     

A Key and Compendium to Species of the Heterodera avenae Group (Nematoda: Heteroderidae)

A key based on cyst and juvenile characters is given for identification of 12 valid Heterodera species in the H. avenae group. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. Cyst characters are most useful for separating species; these include shape, color, cyst wall pattern, fenestration, vulval slit length, and the posterior cone including presence or absence of bullae and underbridge. Also useful are those of second-stage juvenile characteristics including aspects of the stylet knobs, tail hyaline tail terminus, and lateral field. Photomicrographs of diagnostically important morphological features complement the compendium.     

Enzymatic Relationships and Evolution in the Genus Meloidogyne (Nematoda: Tylenchida)

Thirty populations of Meloidogyne of diverse geographic origin representing 10 nominal species and various reproductive, cytological, and physiological forms known to exist in the genus were examined to determine their enzymatic relationships. The 184 bands resolved in the study of 27 enzymes were considered as independent characters. Pair-wise comparisons of populations were performed in all possible combinations to estimate the enzymatic distances (ED) and coefficients of similarity (S). A phylogenetic tree was constructed. The apomictic species M. arenaria, M. microcephala, M. javanica, and M. incognita shared a common lineage. M. arenaria was highly polytypic, whereas conspecific populations of M. javanica and M. incognita were largely monomorphic. The mitotic and meiotic forms of M. hapla were very similar (S = 0.93), suggesting that the apomictic race B evolved only recently from the meiotic race A. The five remaining meiotic species (M. chitwoodi, M. graminicola, M. graminis, M. microtyla, and M. naasi - each represented by a single population) were not closely related to each other or to the mitotic species.     

Noctuidonema daptria,n. sp. (Nematoda: Aphelenchoididae), an Ectoparasite of the Moth Lesmone porcia (Stoll)

Described and illustrated for the first time is a bisexual aphelenchoidid ectoparasitic nematode found on a noctuid male moth in Guadeloupe, West Indies. Sexes are polymorphic, having in common an elongated stylet of 53-69 μm with well-developed basal knobs and double set of protractors, excretory pore near head end, multiple rows of germ cells, and a mucronate tail terminus. The male is particularly distinctive in having a low, smooth head, spicules 38-49 μm long with a tubular rostrum and a ventral arm well separated from the dorsal, an external cloacal cylinder, and a pre- and postanal pair of genital papillae. Distinctive for the female are a unique, muldnucleate uterine gland complex, lack of a functional rectum and anus, and, by marked contrast to the male, a high, hemispherical head marked by six annules and a large uninucleate renette cell.     

Taxonomy of Discocriconemella (Nematoda: Criconematoidea) with a Redescription of D. mauritiensis

The form of the cephalic disc and its taxonomic significance at the species level in the genus Discocriconemella De Grisse &Loof, 1965 is discussed. By light (LM) and scanning electron microscopy (SEM), four groups of disc configurations in females and juveniles are distinguishable. The disc is either round with an uninterrupted margin (group 1), has a deep dorsal and ventral indentation (group 2), is indented medially and laterally giving a four-lobed appearance (group 3), or is round with paired dorsal and ventral projections (group 4). There is no apparent correlation between groups of cephalic discs and other characters such as tail shape or number of body annules. Discocriconemella mauritiensis (Williams, 1960) De Grisse &Loof, 1965 is redescribed from a sugar cane population collected in Mauritius, and the diagnosis of the genus is emended.     

Description of Bakernema dauniense n. sp. (Nematoda: Criconematidae) from Italy

Bakernema dauniense n. sp., a bisexual species from the rhizosphere of Pinus halepensis Mill. in Italy, is described and illustrated. Primary differentiating characteristics of the female are body annules bearing short, membranous projections 1.4-2.2 μm long, an anterior vulval lip slightly overlapping the posterior, and a linearly arcuate vagina. The juvenile differs markedly from adults by having annules with a beaded margin, which lack membranous projections. Generic and specific relationships of B. dauniense n. sp. are discussed. This occurrence is the first for a species of Bakernema in Europe.     

Description of Meloidogyne christiei n. sp. (Nematoda: Meloidogynidae) from Oak with SEM and Host-Range Observations

Meloidogyne christiei n. sp. is described and illustrated from turkey oak (Quercus laevis) in Sanlando Park, Altamonte Springs, Florida. This new nematode species has a distinctive perineal pattern commonly with a high, squarish arch and coarse broken striae which tend to diverge at various angles, especially in and above the anal area. Female labial disc is indented, forming four points or prongs, unlike other species. Eggs are deposited inside the gall in a tubular, coiled manner. Vaginal muscles are exceptionally prominent and dense. SEM observations provided further detail of the perineal pattern and details of the head of females, males, and second-stage juveniles. Galls on the root commonly occur singly, but sometimes in small clusters, and appear as discrete nodules on the side of the root and without adjacent swelling. In general, only one female is found in each gall but occasionally two are present. In greenhouse tests, citrus, tobacco, cotton, pepper, watermelon, peanut, and tomato were not hosts. This nematode occurs throughout central Florida commonly on Q. laevis, the only known host.     

A Key and Diagnostic Compendium to the Species of the Genus Tylenchorhynchus Cobb, 1913 (Nematoda: Belonolaimidae)

An identification key to 111 species of Tylenchorhynchus is given. Tylenchorhynchus is defined as containing only those species with four incisures in the lateral field. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. Some species in a related but unnecessary genus were placed in the genus Tylenchorhynchus, based on morphological structures and logical groupings of the species. Bitylenchus iphilus is transferred to Tylenchorhynchus. The diagnosis of Tylenchorhynchus is emended, and a list of all the valid species of the genus is given. The characters most useful for separating species are the stylet length, shape of lip region, number of lip annules, shape of tail and tail terminus, number of tail annules, and position of vulva (V%). As defined in the paper, the genus currently is composed of 111 valid species.     

Vittatidera zeaphila (Nematoda: Heteroderidae), a new genus and species of cyst nematode parasitic on corn (Zea mays)

A new genus and species of cyst nematode, Vittatidera zeaphila, is described from Tennessee. The new genus is superficially similar to Cactodera but is distinguished from other cyst-forming taxa in having a persistent lateral field in females and cysts, persistent vulval lips covering a circumfenestrate vulva, and subventral gland nuclei of the female contained in a separate small lobe. Infective juveniles (J2) are distinguished from all previously described Cactodera spp. by the short stylet in the second-stage juvenile (14-17 μm); J2 of Cactodera spp. have stylets at least 18 μm long. The new species also is unusual in that the females produce large egg masses. Known hosts are corn and goosegrass. DNA analysis suggests that Vittatidera forms a separate group apart from other cyst-forming genera within Heteroderinae.