Plant nematodes in South Africa . 7 . A check list of plant nematodes from the Fynbos Biome , with a description of Helicotylenchus curatus sp

Plant nematodes recorded during surveys in the Fynbos Biome are listed and a new Helicotylenchus species is described. Helicotylenchus curatus sp. n. is characterised by stylet length (42-46 μm in females, 37-40 μm in males), presence of two rudimentary subdorsal and two rudimentary subventral lobes on the labial disc, first lip annulus divided into six sectors, presence of fasciculi and presence of males. Nine families represented by 32 genera and 152 species were identified from the Fynbos Biome. The genera Criconema, Helicotylenchus, Hemicycliophora, Rotylenchus, Scutellonema and Xiphinema were found in more than 30 % of the localities, whereas Caloosia, Criconemoides, Ditylenchus, Geocenamus, Hemicriconemoides, Heterodera, Hoplolaimus, Longidorus, Meloidogyne, Mesocriconema, Ogma, Paralongidorus, Paratrichodorus, Paratylenchus, Pratylenchoides, Pratylenchus, Rotylenchulus, Trichodorus and Tylenchorhynchus were found at fewer localities. The genera Anguina, Hirschmaniella, Histotylenchus and Zygotylenchus were each identified from a single locality.


Introduction
In 1987, the South African Plant-Parasitic Nematode Survey (SAPPNS) programme was initiated with the aim to make a comprehensive assessment of the nematode biodiversity resources of South Africa.One of the objectives of the SAPPNS is to compile an inventory of the plant-parasitic nematodes of South Africa.Although nematodes constitute an abundant and highly diverse group of invertebrates, very little is known about their diversity in fynbos.The checklist reflects on collecting done by the Agricultural Research Council, Western Cape Nature Conservation Board, Rand Afrikaans University and University of Stellenbosch (Heyns 1971;Kleynhans et al. 1996;Marais & Swart 1999;Van den Berg et al. 2003;Van den Berg & Tiedt 2000) during the past 30 years.The Fynbos Biome is one of the biomes defined by Low & Rebelo (1996).In South Africa, vegetation structure and climate mostly define these ecological zones.The Fynbos Biome is considered by many to be synonymous with the Cape Floral Kingdom, but this biome refers only to the two vegetation groups, viz., Fynbos and Renosterveld within the region (Low & Rebelo 1996).Renosterveld is characterised by the dominance of members of the Asteraceae, specifically one species Elytropappus rhinocerotis (renosterbos), from which the vegetation type gets its name.Although renosterbos is the characteristic dominant plant, other plants are also prominent.These plants are all shrubs, characterised by small, tough grey leaves (Rebelo 1996a).The various Fynbos vegetation types comprise most of the area of the Fynbos Biome.Fynbos is characterised by the presence of three elements, viz., a component belonging to the Cape Reed family (Restionaceae), an ericoid or heath component and a proteoid component.Fynbos is also characterised by the presence of a number of endemic or near-endemic plant families, viz., Bruniaceae (Blacktips), Geissolomaceae (Guyalone), Grubbiaceae (Sillyberry), Penaeaceae (Brickleaf), Retziaceae (Buttbush), Roridulaceae (Dewstick) and Stilbaceae (Candlestick) (Rebelo 1996b).
Helicotylenchus is a cosmopolitan genus with more than 200 species described (Marais 2001).This genus is found in all the biomes of South Africa.Thirty-one species of Helicotylenchus have been reported from South Africa.This paper is the result of an ongoing investigation on the genus Helicotylenchus (Marais 1993(Marais , 1998(Marais , 2001;;Marais & Buckley 1992;Marais & Quénéhervé 1996;Marais & Quénéhervé 1999;Marais et al. 2000;Van den Berg & Marais 1995;Van den Berg et al. 2003).

Material and methods
Soil samples were collected with a garden trowel, soil auger or spade to a depth of about 20-25 cm at each locality.Samples were collected in unprotected areas such as farms and plantations but also in nature reserves, wilderness areas and national parks.Nematodes were extracted from 250 cm 3 of soil, killed in water, preserved in FAA, TAF or FPG and mounted in anhydrous glycerine (Hooper & Evans 1993;Jenkins 1964;Kleynhans 1997;Koen & Furstenberg 1970;Netscher & Seinhorst 1969;Seinhorst 1959).To obtain females of Meloidogyne for identification, subsamples of each soil sample, in which root-knot nematode juveniles were found, were planted to tomato seedlings (cv.UC82B or Roma VF) in a greenhouse.After six weeks, females were extracted from the roots and mounted in anhydrous glycerine (Kleynhans 1991).For scanning electron microscopy, FPG-preserved specimens were used after dehydration in increasing concentrations of acetone.Following conventional critical-point drying and gold/palladium-coating (15 nm), specimens were viewed with a Quanta 200 ESEM.
to anus) and presence of males vs absence of males.Females of the new species can be distinguished from H. coomansi females in lip region shape (truncate with basal annuli bulging out vs continuous), labial disc characteristics (with two rudimentary subdorsal and two rudimentary subventral lobes present vs without any lobes), number of lip annuli (six to seven vs four to five), presence vs absence offasciculi, a-value (17.5-27.5 vs 35-40), stylet length (42-46 µm vs 39-42 µm), m-value (52-56 % vs 48-50 %), position of phasmids (opposite anus to five annuli posterior to anus vs five to eight annuli anterior to anus) and tail form (asymmetrical, more curved dorsally, with rounded end vs straight, tapering dorsally with unstriated ventral portion).The males differ in body length (760-944 µm vs 1190-1260 µm), position of excretory pore from front (121-126 µm vs 161 µm) and tail length (26-39 µm vs 41 µm -calculated from paratype material.).The new species can be separated from H. macrostylus in presence of fasciculi vs absence, m-value (52-56 % vs 42-45 %), lip region shape (truncate with basal annuli bulging out vs continuous), labial disc characteristics (rectangular, with two rudimentary subdorsal and two rudimentary subventral lobes vs round with no lobes), first lip annulus divided vs not divided.
EtymologyFrom the Latin cura, meaning to care, in recognition of Liezel Scheepers for her invaluable assistance.