Zeng Qi Zhao

Diploscapter formicidae sp n. (Rhabditida: Diploscapteridae), from the ant Prolasius advenus (Hymenoptera: Formicidae) in New Zealand

Diploscapter formicidae sp. n. was collected from the ant Prolasius advenus and its nests in native beech forests of the South Island, New Zealand. This is a new host record for the nematode genus and the first report of an ant associate from the southern hemisphere. Diploscapter formicidae sp. n. appears to be native to New Zealand. No males were found from collections from 16 nests, in agreement with previously published data on the other members of this genus, suggesting that males are absent or very rare. The adult females have bilateral symmetry of the head, characteristic dorsal and ventral projections of the putative cheilostom with paired hook-like structures or hamuli, expansive membranous lateral lip flaps or laciniae, gymnostom and stegostom with parallel walls, a swollen procorpus, large terminal bulb with a strong valve, paired ovaries with medial vulva, and a short conoid tail with slender pointed or spicate tip. Scanning electron micrographs of the structure of the head confirmed that the lateral laciniae with finger-like tines or filopodia are moveable (alternately covering and exposing the mouth). These lateral lip flaps are located posterior to the stoma, but anterior to the pore-like amphidial openings. The anterior margin of the cheilostom possesses apomorphic lateral bell-shaped projections and the hamuli are broader and less pointed than other species that have been examined. Molecular phylogeny of near full-length small subunit, D2/D3 expansion segments of the large subunit rRNA gene and heat shock protein 90 (Hsp90) gene showed that D. formicidae sp. n. is monophyletic with the Diploscapter species and isolates available in GenBank, but is on an independent trajectory supporting separate species status.

Litylenchus coprosma gen. n., sp. n. (Tylenchida: Anguinata), from leaves of Coprosma repens (Rubiaceae) in New Zealand

Summary – A new genus and species of anguinid nematode, Litylenchus coprosma gen. n., sp. n., was recovered from leaves of Coprosma repens A. Rich. from an amenity planting in Wellington, New Zealand. The genus is characterised by having slender males and slender or semi-obese females, pharynx with a weak non-muscular median bulb, a terminal bulb containing the pharyngeal glands, female with a single gonad having a quadricolumella and post-uterine sac; male with arcuate spicules and the bursa arising 1-2 anal body diam. anterior to the cloacal aperture and extending nearly to the tail tip, and does not induce galls, only foliar chlorosis. The species is characterised by having a short, robust stylet with conus forming ca 40% of stylet length and three well developed rounded knobs, secretory/excretory pore opening posterior to the nerve ring, terminal bulb abutting the intestine, and tail tip of variable form. Molecular phylogeny of near full length small subunit, D2/D3 expansion segments of the large subunit and internal transcribed spacer rRNA genes support the description of L. coprosma gen. n., sp. n. as a new genus and species.

Description of Trischistoma abharensis n. sp. (Nematoda: Trischistomatidae) and first record of Tripylella intermedia (Bütschli, 1873) Brzeski & Winiszewska-Ślipinska, 1993 (Nematoda: Tripylidae) from Iran.

Two populations of the genera Trischistoma and Tripylella were recovered from the rhizosphere of grapevines and mosses growing on alder trees in Zanjan and Guilan provinces, respectively, Iran. The nematodes were identified as Trischistoma abharensis n. sp. and Tripylella intermedia, respectively. Trischistoma abharensis n. sp. is characterized by having females with body length 1069-1322 μm, presence of sparse somatic setae on the sublateral body, absence of ventromedian cervical setae, a distinct dorsal tooth directed anteriorly, absence of post-vulval uterine sac, and tail with one pair of subdorsal caudal setae. Males were not found. Tripylella intermedia is characterised by having females with body length 905-990 μm, annulated cuticle, stoma with two chambers: with dorsal tooth lying in posterior buccal chamber, and one large subventral and one small subventral tooth, respectively lying in posterior and anterior buccal chambers, cardiac glands large, composed of six fused cells, and tail 121-155 μm long, ventrally bent, anterior half broad, then suddenly narrowing, with posterior half tapered narrowly and cylindrically. The phylogenetic relationships of both species were analysed using sequences of the partial small subunit (SSU) and D2/D3 expansion segments of large subunit (partial LSU) of ribosomal RNA genes and are discussed.

Zeatylenchus pittosporum gen. n., sp n. (Tylenchida: Anguinata), from leaves of Pittosporum tenuifolium (Pittosporaceae) in New Zealand

A new genus and species of anguinid nematode, Zeatylenchus pittosporum gen. n., sp. n., was recovered from leaves of Pittosporum tenuifolium from Hahei, Coromandel Region, North Island, New Zealand. The genus is characterised by having slender males and females, excretory pore opening near the lips and level with the knobs of the retracted stylet, pharynx with a weak non-muscular median bulb, pharyngeal glands overlapping the intestine, females with a single gonad with a quadricolumella and post-uterine sac; and males with slender arcuate spicules and the bursa arising <1 anal body diam. anterior to the cloacal aperture and extending ca 30% of distance to the tail tip. Its feeding does not induce galls, only foliar chlorosis. The species has particular characters, including a short, robust stylet with conus forming ca 40% of stylet length and small rounded compact knobs, and tail offset dorsally with a pointed tip. Molecular phylogeny of near full length small subunit, D2/D3 expansion segments of the large subunit and internal transcribed spacer rRNA genes support the description of Zeatylenchus pittosporum gen. n., sp. n. as a new genus and species.

Phylogenetic relationships within the Cyatholaimidae (Nematoda: Chromadorida), the taxonomic significance of cuticle pore and pore-like structures, and a description of two new species

The family Cyatholaimidae Filipjev, 1918 is a relatively diverse group of mainly marine nematodes which has been shown to be monophyletic by morphological and molecular phylogenetic analyses. There are, however, no morphological synapomorphies for any of the four subfamilies that currently comprise the Cyatholaimidae. The two types of cuticle pore and pore-like structures often observed in cyatholaimids may be of taxonomic significance, but the terminology used is inconsistent, and their description is often too limited to provide sufficient information for comparisons. Here, we describe two new cyatholaimid species, Paracanthonchus miltommatus sp. n. and Metacyatholaimus delicatus sp. n., from intertidal and upper continental slope sediments of New Zealand, and investigate the distribution and morphology of cuticle pore and pore-like structures in these two new species using light and scanning electron microscopy. We also investigate phylogenetic relationships within the Cyatholaimidae using SSU and D2-D3 of LSU rDNA sequences. The first type of cuticle structure, first termed pore complex by Wright & Hope (Can J Zool 46:1005–1011, 1968), consists of circular structures usually arranged in sublateral, subventral and subdorsal longitudinal rows, with a slit-like pore and ring-like development of dense material in the middle cuticle layer and typically associated with an underlying cell. The second, less studied type, for which we propose the term lateral pore-like structure, consists of structures arranged along the mediolateral lines in one or more longitudinal rows or sometimes irregularly, usually with a central, non-cuticularised dome, and a round or elliptical cuticularised opening supported by unmodified or modified punctations at anterior and posterior extremities. The function of the lateral pore-like structures remains unclear but their morphology is inconsistent with their descriptions as pores or modified punctations by some authors. The limited information available suggests that the number, distribution, and morphology of pore complexes and lateral pore-like structures could provide taxonomically useful information for defining cyatholaimid genera such as Longicyatholaimus Micoletzky, 1924 and Marylynnia (Hopper, 1972). Our SSU-based molecular phylogenetic analysis retrieved two monophyletic clades with low support, which approximately correspond to the subfamilies Paracanthonchinae and Cyatholaiminae; however, we found that Praeacanthonchus, which is currently classified with the Cyatholaiminae based on the structure of the gubernaculum, may be better placed in the subfamily Paracanthonchinae. This finding suggests that the gubernaculum structure may not be a meaningful character for defining cyatholaimid subfamilies or genera. Features of the cuticle, some of which are already used for defining genera such as Metacyatholaimus Schuurmans Stekhoven, 1942, may better represent phylogenetic relationships within the family, and should, therefore, be described more comprehensively in the future.

First record of the root knot nematode, Meloidogyne minor in New Zealand with description, sequencing information and key to known species of Meloidogyne in New Zealand

Meloidogyne minor Karssen et al. 2004 was collected from perennial ryegrass (Lolium perenne L.) growing in a sports ground in Christchurch, New Zealand. This is a new record for M. minor, the first report of this nematode occurring in New Zealand, and the second report from the southern hemisphere (after Chile). In general, the New Zealand isolate of M. minor corresponds well to the descriptions of M. minor given by Karssen et al. (2004). The New Zealand isolate is characterized by having a female with dorsally curved stylet, 13-14 μm long, with transversely ovoid knobs slightly sloping backwards from shaft; rounded perineal pattern; and male with stylet 16-19 μm long, large transversely ovoid knobs sloping slightly backwards from shaft; head region not set off, labial disc elevated, lateral lips prominent; and second stage juvenile 370-390 μm long, with hemizonid posterior but adjacent to excretory pore; tail 53-63 μm long; and a distinct hyaline tail terminus 14-18 μm long. In addition, molecular phylogeny using near full length small subunit (SSU), D2/D3 expansion segments of the large subunit (LSU), the internal transcribed spacer region (ITS1 and 2), and the intergenic spacer (IGS2) of the ribosomal rDNA supports the identification.

Molecular characterisation of five nematode species (Chromadorida, Selachinematidae) from shelf and upper slope sediments off New Zealand, with description of three new species

Limited molecular sequence data are available for selachinematid nematodes, with little or no data from the Southern Hemisphere or habitats beyond the subtidal zone. Here, we provide molecular sequence data for the small subunit (SSU) 18S rDNA gene and D2-D3 region of large subunit (LSU) 28S rDNA gene of three new (Cheironchus haurakiensis n. sp., Halichoanolaimus anisospermus n. sp., and Bendiella longicauda n. sp.) and two known selachinematid species (Pseudocheironchus ingluviosus Leduc, 2013 and Synonchiella rotundicauda Leduc, 2013) from shelf and upper slope environments off northeastern New Zealand. Cheironchus haurakiensis n. sp. is characterised by having a multispiral amphideal fovea with five turns, lateroventral mandibles with central arm curved distally and bearing 4-5 pointed projections, and each palm bearing 4-5 pointed projections, ten precloacal supplements in a 1 + 9 arrangement, spicules 78 µm long, and blunt conical tail with thickened cuticle. Halichoanolaimus anisospermus n. sp. is characterised by having an amphideal fovea with 5-6 turns, anterior portion of buccal cavity with cuticularised rhabdions terminating in three sets of seven pairs of teeth (denticles), with the central pair of each set positioned above the other six, dimorphism in size of sperm cells between anterior and posterior testes, gubernaculum consisting of two detached lateral pieces (crurae) tapering distally, three small precloacal supplements consisting of slightly thickened and raised cuticle, and a conicocylindrical tail with conical portion 32-38% of total tail length. Bendiella longicauda n. sp. is characterised by having two dorsosublateral rows of pores from midbody to level of cloaca, amphideal fovea with 4.5 turns, posterior rhabdions with numerous small denticles, spicules 2.1 cloacal body diameters long, a conicocylindrical tail 13.3 cloacal body diameters long and with conical portion 8% of tail length. Preliminary phylogenetic analyses for the family Selachinematidae do not provide evidence of clustering according to depth (intertidal/subtidal vs shelf/upper slope) or geographical location (New Zealand vs Northern Hemisphere). The number of available Selachinematidae sequences, however, remains limited and comprehensive analyses based on larger number of sequences will be necessary to provide more solid conclusions.

Above-Ground Nematodes of conifers in South-Eastern Australia

Abstract The above-ground nematode fauna of Pinus and native conifers in south-eastern Australia was surveyed from the Kuitpo Forest (and nearby Rocky Creek) and The South-East Region of South Australia; the South-West and the Gippsland Region of Victoria; the Hume Region in New South Wales; and the Murray Mallee Region of SA. A total of 1140 samples from Pinus radiata, 50 from Pinus pinaster and 40 from Callitris preissii was examined. No nematodes were found in wood or young shoots of conifers. By contrast, nematodes were common in the bark samples. Extracted nematodes were classified morphologically into five trophic groups namely: aphelenchids (plant, hyphal, algal and predacious feeders), rhabditids (bacterial feeding), Macrolaimus spp. (saprophagous), tylenchids (plant parasites, insect parasites and hyphal feeders), and dorylaimids (predacious, omnivorous, hyphal and plant feeders). Aphelenchids were the most common trophic group.

Morphological and molecular characterisation of Spirinia antipodea Leduc n. sp. (Nematoda: Desmodoridae), a cryptic species related to S. parasitifera , from the coast of New Zealand

Spirinia parasitifera is a common nematode species recorded from coastal habitats of the White, North and Barents Seas, the Northwest Atlantic, the Maldives and Australia, and exhibits a high degree of variability in some morphological characters. For these reasons it has been suggested that S. parasitifera is a species complex comprised of several distinct but potentially cryptic species. However, no study has yet combined molecular and morphological approaches to verify this assertion. Here, we describe S. antipodea n. sp., a species morphologically very similar to S. parasitifera , from the coast of New Zealand. Spirinia antipodea n. sp. differs from the original description of S. parasitifera as well as subsequent descriptions by other authors in at least one body dimension, but no single trait differs consistently between the New Zealand specimens and all descriptions of S. parasitifera . Phylogenetic analyses showed that the new species is distinct from other species of the genus, including S. parasitifera specimens sampled near the type locality. The S. antipodea n. sp. SSU sequence differed from other Spirinia sequence by 2.9-5.3%, whilst D2-D3 of LSU sequences differed by 12.5-18.9%. The consensus SSU tree also recovered three distinct S. parasitifera clades, which provides support for the existence of a species complex. Because it is not possible to determine whether the variability in morphological characters observed among descriptions of S. parasitifera is intra- or interspecific, and therefore to determine which trait can reliably be used to differentiate between S. antipodea n. sp. and S. parasitifera , the new species is best differentiated from S. parasitifera and other closely related species based on SSU sequences rather than morphological characters.

Phylogenetic position of the enigmatic deep-sea nematode order Rhaptothyreida: A molecular analysis

The placement of the rare deep-sea nematode order Rhaptothyreida remains unclear due to the unique morphology of this group, an unknown life cycle with morphologically distinct juvenile stages which may or may not be parasitic, and lack of molecular sequences. Here, we investigate the phylogenetic placement and status of the Rhaptothyreida based on SSU and D2-D3 of LSU rDNA sequences of Rhaptothyerus typicus specimens obtained from the continental slope of New Zealand. Molecular sequences of three adults and a late stage juvenile were identical, confirming that they belong to the same species despite pronounced morphological differences. We observed the presence of the rare nucleotide transition A → G and transversion G → Y in the loops of Hairpin 35 and 48 regions, which is consistent with the placement of R. typicus within the order Enoplida. Rhaptothyreus typicus was consistently recovered as a long branch clade in SSU and D2-D3 of LSU analyses, which can have a destabilising effect on tree topology. After Gblocks were used to remove sites of questionable alignment, R. typicus was placed in a clade comprising Trissonchulus, Dolicholaimus and Ironus sequences (family Ironidae, order Enoplida) in both Bayesian and Maximum Likelihood SSU topologies. Depending on which alignment algorithm was used, analyses of LSU sequences focusing on enoplid taxa either suggested a relationship between R. typicus and Halalaimus (family Oxystominidae) or did not identify any clear relationships. Overall, our results provide strong evidence for placing R. typicus and the family Rhaptothyreidae within the order Enoplida, although further work is required to clarify relationships between rhaptothyreids and other enoplid taxa. A parasitic lifestyle could explain the unique morphology of this group, their highly divergent SSU and LSU rDNA molecular sequences, and the marked morphological differences between late juveniles and adults. Further molecular investigations targeting both free-living and parasitic early juvenile life stages in potential deep-sea hosts are needed to better understand the evolution of this unusual nematode taxon.