Phylogenetic position of the parasitic nematode Trophomera (Nematoda, Benthimermithidae): A molecular analysis.

Benthimermithid nematodes are parasites of invertebrates currently classified within their own order. Relationships between the Benthimermithida and other nematode orders, however, remain unclear due to their relatively simple morphology, their rarity, and paucity of molecular sequence data. Here, we combine molecular sequences obtained from Trophomera cf. marionensis in the Kermadec Trench with existing Trophomera sequences to determine the phylogenetic position of benthimermithids. Our SSU analyses showed Trophomera to be most closely-related to the order Plectida, subclass Chromadorea. Trophomera sequences formed a well-supported monophyletic clade placed within the Plectida, however relationships with other taxa within the order could not be resolved. Based on the result of these analyses, we propose that the family Benthimermithidae be moved to the order Plectida, however, future research on the classification of the family should focus on the benthimermithid genera Bathynema and Adenodelphis, for which no molecular sequences are yet available. We could not confirm a relationship between Trophomera and the family Camacolaimidae, which are both characterised by the presence of a stylet or stylet-like structure in the buccal cavity. Stylets are a common feature of parasitic nematodes, and its presence in a free-living benthimermithid ancestor perhaps similar to present-day camacolaimids could have facilitated a transition to a parasitic lifestyle. Our SSU phylogenetic analyses show that some features of benthimermithids, including the trophosome and a parasitic life cycle where the adults mate outside the host, have evolved independently in different groups of parasitic nematodes.

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.

An index to new genera and species of Nematoda in Zootaxa from 2007 to 2012.

Of 104 papers on nematodes published in Zootaxa from 2007 to 2012, seventy five, by 136 authors from 27 countries, described eight new genera and 155 new species. A bibliographic analysis of these papers and a list of new genera and species are presented in this paper.

A new species of the genus Tripylina Brzeski, 1963 (Nematoda: Enoplida: Trischistomatidae) from Shanxi province, China.

Tripylina puxianensis n. sp. is described and illustrated from Shanxi province, China. It is characterized by having a triangular dorsal tooth, pointing towards the ventral side, anterior to two sub-ventral teeth, with dorsal and sub-ventral teeth similar in shape and size; one ventromedian seta in the cervical region; vulva with protruding lips, absence of post-uterine sac; and a pair of setae on the tail; male not found; female body length 1048-1331 µm, a = 25.5-33.8, b = 5.5-6.2, c = 14.4-23.1, c' = 2.1-3.5 and V = 56.1-68.5%. The phylogenetic relationships among species in the genus Tripylina were analyzed using data from the SSU (small subunit) and D2/D3 expansion segments of the LSU (large subunit) rDNA. These analyses confirmed that T. puxianensis n. sp. is different from other members of the genus for which sequences are available.

A new species of the genus Tripylina Brzeski, 1963 (Nematoda: Enoplida: Trischistomatidae) from Zhejiang Province, eastern China.

Tripylina zhejiangensis n. sp. is described and illustrated from Zhejiang province, eastern China. It has a robust body, smooth cuticle with numerous pores, two small subventral teeth in the posterior part of the large triangular dorsal tooth, one ventral-median seta in the cervical region and a pair of setae on the tail. Females are characterized by a body length of 1325-1573 µm, a = 23.3-31.2, b = 5.5-6.6, c = 13.6-19.4, c'= 2.7-3.6 and V = 61.1-68.1%. Small subunit (SSU) and D2/D3 expansion segments of large subunit (LSU) of ribosomal DNA were used to analyze the phylogenetic relationships of sequenced species in the genus Tripylina. Tripylina zhejiangensis n. sp. varied significantly from other related nematodes both in morphological characterizations and phylogenetic analyses.

Molecular characterization of free-living nematodes from Kermadec Trench (Nematoda: Aegialoalaimidae, Xyalidae) with description of emAegialoalaimus/em emtereticauda/em n. sp.

The Kermadec Trench is the world's fifth deepest trench and extends from approximately 26 to 36°S near the northeastern tip of New Zealand's North Island. Here, we describe a new species of Aegialoalaimus, a nematode genus with unusual buccal cavity and pharynx morphology, from a site at 9540 metres water depth in Kermadec Trench, and provide the first SSU and D2-D3 of LSU sequences for Aegialoalaimus, Manganonema, Metasphaerolaimus constrictus and Daptonema amphorum. Aegialoalaimus tereticauda n. sp. is characterised by body length 755-864 µm, cephalic sensilla papilliform ( 1 µm long), excretory pore located slightly anterior to posterior bulb in males and slightly anterior to nerve ring in females, arcuate spicules 18-22 µm long, gubernaculum present, precloacal supplements absent, and cylindrical tail 58-64 µm long with rounded tip. Relationships between Aegialoalaimus and Chromadorean orders could not be elucidated based on our SSU analysis; no link could be found with the Plectida, where the Aegialoalaimidae is currently placed, or with the Isolamiida or Cylindrolaimus (Areaolaimida), which share a similar and unusual buccal and pharynx morphology. Our SSU phylogenetic analysis confirms the placement of Manganonema within the Xyalidae, although relationships with other xyalid genera remain unclear. The Sphaerolaimidae formed a clade together with the Monhysteridae, which contradicts the current classification where the Sphaerolaimidae and Xyalidae are classified together into the superfamily Sphaerolaimoidea and the Monhysteridae into the Monhysteroidea. Although limited research has been conducted on the nematode diversity in Kermadec Trench to date, the available data show that half of all invertebrate species known from the trench are nematodes, which highlights the importance of conducting further taxonomic research on this group in hadal environments.

First record of Bursaphelenchus hildegardae Braasch et al., 2006 (Nematoda) in New Zealand with updated information on morphology, sequencing and a key to species of the eggersi-group.

Bursaphelenchus hildegardae Braasch et al., 2006 was collected from pine wood (Pinus radiata) growing in Kaingaroa Timberlands, and a bark beetle, Hylastes ater Paykull, 1800 in New Zealand. This is a new record for B. hildegardae, occuring in New Zealand, and the second report from the southern hemisphere in addition to Australia. In general, the New Zealand isolate of B. hildegardae corresponds well with the description of B. hildegardae given by Braasch et al. (2006) from Germany. The New Zealand isolate is characterized by having an adult body length of 8071190 m, medium a ratios (47.558.5 for female and 44.660.1 for male), b ratios of 9.814.5 (female) and 10.212.7 (male), c ratios of 18.825.2 (female) and 21.632.4 (male), c ratios of 4.04.4 (female) and 2.12.7 (male), and is characterised by having three incisures in the lateral fields, thorn-shaped spicules with a distinctly dorsally-bent thin hook-like condylus, and a dorso-ventally visible terminal bursa. In addition, molecular phylogeny using near full length small subunit (SSU), D2/D3 expansion segments of the large subunit (LSU) and the internal transcribed spacer region (ITS1 and 2) of the ribosomal rDNA supports the identification. A key to Bursaphelenchus species in the eggersi-group is given.

Isolation of Litylenchus coprosma from Coprosma macrocarpa, a new host and distribution in New Zealand.

Coprosma macrocarpa, known as the large-seeded coprosma or coastal karamu, is a shrub endemic to New Zealand. To our knowledge, no reports of plant parasitic nematodes associated with C. macrocarpa have been reported. Here we report the detection and identification of the nematode, Litylenchus coprosma, extracted from C. macrocarpa in Otata Island.

Tripylella australis sp. nov. and Tripyla setifera Bütschli 1873 (Nematoda: Triplonchida: Tripylidae) from Australia.

This paper describes a new species of Tripylella and gives a new record of Tripyla (family Tripylidae) in Australia, and provides a key to species in the genus Tripylella. Tripylella australis sp. nov. is characterized by having females with a long body (1804-1832 µm), a=41-42, b= 4.4-4.5, c=10.3-11.3, c'=5.4-6.4 and V=51-54%, outer labial setae 13-14 µm long and cephalic setae 3.7-4.5 µm long in one whorl, dorsal tooth posterior to two subventral teeth, tail tapering uniformly, and four single caudal setae on the dorsal part of the tail. Males are similar to females, and have a long body (1870-2014 µm), a=50-55, b= 4.7-4.9, c=11.3-11.4, c'=5.8-6.0 and T=53-56%, horn-shaped spicules, 36-38 µm long, a straight gubernaculum 14-16 µm in length, tail tapering almost uniformly, and four caudal setae on the dorsal part of the tail. A key for identification of Tripylella species is presented. Tripyla setifera Bütschli 1873 is recorded for the first time in Australia, and is re-described.

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.

A new species and a new record of Trischistoma Cobb, 1913 (Nematoda: Enoplida: Trischistomatidae) from Shanxi Province, China.

This paper describes a new species and gives a new record and a re-description of a known species of Trischistoma Cobb, 1913. Trischistoma taiguensis sp. nov. is characterized by having one pair of caudal setae on the tail; female body length of 562-699 µm, a = 35-42, b = 4.1-4.7, c = 11-14, c' = 3.9-4.6 and V = 79-82%. For the first time, Trischistoma pellucidum Cobb, 1913 is recorded from Shanxi Province, China. The phylogenetic relationships among species in the genus Trischistoma were analyzed using data from the SSU (small subunit) and D2/D3 expansion segments of the LSU (large subunit) rDNA sequences. These analyses confirmed that T. taiguensis sp. nov. and T. pellucidum differ from other known members of the genus for which sequences are available in GenBank.

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