Abstract

Two new nematode species of the genus Schistonchus were recovered from syconia from a single Ficus hispida caprifig tree in Guangzhou, China. They are described herein as Schistonchus guangzhouensis n. sp. and S. centerae n. sp. Schistonchus guangzhouensis n. sp. is characterised by possessing the longest postuterine sac (PUS) of all currently described females in the genus (84-148 μm or >3.5 vulval body diam. (VBD) long), excretory pore situated near the level of the metacorpus, two pairs of subventral papillae on the male tail, and unique recurved and mitten-shaped spicules. Schistonchus centerae n. sp. is characterised by a unique fusiform tail tip and short PUS (8-20 μm or <1.0 VBD long) in reproductive females, excretory pore located near the head, spicules with an indistinct rostrum, male tail with three pairs of papillae, and broadly truncate tail tip. Both new species were easily differentiated from each other and other members of the genus for which sequences of the D2/D3 expansion segments of the large subunit rRNA gene (LSU) and partial small subunit rRNA gene (SSU) were available. Phylogenetic analysis also supported a monophyletic Schistonchus within a well-supported clade of Aphelenchoididae (sensu Hunt, 1993) and shared a most recent common ancestor with Aphelenchoides and Laimaphelenchus.

In: Nematology

Abstract

Uliginotylenchus changlingensis n. sp. is described from the rhizosphere of potato roots in Changling county, Jilin province, China. The species is characterised by a long body (female: 846-952 μm, male: 785-934 μm), completely areolated lateral field with three incisures, high and rounded offset lip region bearing five or six annuli, long stylet (female: 24.0-26.0 μm, male: 23-28 μm), presence of vulval flaps, female tail subconoid with 28-39 annuli and terminus bluntly conoid without striations, distinct phasmids and gubernaculum distally crescent-shaped. It is closely related to U. cylindricaudatus and U. bifasciatus. It differs from U. cylindricaudatus mainly by the different number of labial annuli (5-6 vs 7-8), different tail shape (subconoid vs subcylindrical) and by vulval flaps present vs absent. It differs from U. bifasciatus mainly by different female stylet length (24-26 vs 19-20 μm), tail shape and annuli (subconoid with 28-39 annuli with smooth terminus vs subcylindrical with 42-48 annuli with annulated terminus). It further differs from other species of Uliginotylenchus by the offset vs continuous labial region.

In: Nematology

Summary

A new nematode species was recovered from the syconia of Ficus hirta var. roxburghii from Chaozhou, Guangdong, China. It is described herein as Ficophagus chaozhouensis n. sp. and is characterised by possessing the combined characters of a short post-uterine sac, excretory pore located near the head, amoeboid sperm, three pairs of subventral papillae on the male tail, rounded male tail tip with mucron (occasionally swollen), absence of gubernaculum (or apophysis), a blunt rosethorn-shaped spicule without a terminal cucullus, and a digitate rostrum with a broadly squared tip. Ficophagus chaozhouensis n. sp. was separated from other sequenced species by differences in the partial small subunit (SSU) rRNA gene and D2-D3 expansion segments of the large subunit (LSU) rRNA gene. Phylogenetic analysis with LSU D2-D3 expansion segment sequences suggested that F. chaozhouensis n. sp. is clustered in the same highly supported monophyletic clade with F. aculeata, F. maxima and F. yoponensis, and is sister to F. aculeata.

In: Nematology

Abstract

Acrostichus puri n. sp., isolated from the body of a sweat bee, Augochlora pura mosieri, is described and figured. The new species is morphologically, molecularly and biologically very similar to A. halicti, i.e., these two species share a very complicated gubernaculum structure, distally hooked spicules with a triangular flap-like rostrum, stomatal polymorphism and synchronised associations with halcitid bees. The new species can be distinguished from A. halicti by its spicule morphology, distinctive squared manubrium and sharply bent (= ca 90° or L-shaped) distal tip vs an indistinctive rounded manubrium and a strongly recurved (= ca 180° or U-shaped) distal tip; gubernaculum with narrower, longer, anterior part and more complex posterior part than A. halicti, and tail of both sexes, with a long and filiform spike on the male or female tail vs a short spike (male) or conical tail (female). These two species also differ from each other by significant molecular sequence differences in SSU (2.0%), D2/D3 LSU (4.5%) and mtCOI (9.2%), and are reproductively incompatible in mating tests.

In: Nematology

Abstract

Bradynema listronoti n. sp. was collected from the haemocoel of adults and the environment of the carrot weevil, Listronotus oregonensis in Quebec, Canada. It is the first species of Bradynema to be reported from weevils and is described and illustrated herein. Bradynema listronoti n. sp. appears to be closest to B. trixagi because of the shared characteristic of a peloderan bursa in males which is not present in the other seven described species in the genus. Bradynema listronoti n. sp. can be differentiated from all members of the genus by the possession of a degenerate, but sometimes visible, stylet remnant, non-degenerate pharynx in males and by the often dorsally-curved C-shaped body (ventral side is convex) of parasitic females. The vestigial stylet in all stages argues for placement of B. listronoti n. sp. within the genus Bradynema, but some characteristics, such as a non-degenerate pharynx in males, suggest placement in a new genus or affinities with other genera in the Allantonematidae, e.g., Allantonema. Molecular analysis of the near full length SSU, D2/D3 expansion segments of the large subunit (LSU) rDNA and partial mitochondrial DNA COI (mtCOI) suggest that this nematode is unique and D2/D3 analysis supports monophyly with B. rigidum, the only other member of the genus to be sequenced.

In: Nematology

Abstract

A nematode recovered from syconia of Ficus hirta from Guangzhou, P. R. China, during a survey of nematode biodiversity from 2007 to 2009, is described herein as Schistonchus hirtus n. sp. and is differentiated by a combination of morphological characters, including excretory pore (EP) located near the metacorpus, a short post-uterine sac (PUS) (0.5 vulval body diam. (VBD) long), rose thorn-shaped spicules, amoeboid sperm, absence of gubernaculum, three pairs of subventral papillae on the male tail, host-Ficus and host-wasp species and DNA sequence data. Morphologically, S. hirtus n. sp. is close to S. centerae, S. altermacrophylla, S. aureus, S. laevigatus and S. virens based upon the length of the PUS (about 0.5 VBD long). However, the relative position of the EP in S. hirtus n. sp. is very different from these species (near metacorpus vs near head). With regard to the EP character, S. hirtus n. sp. is very similar to S. macrophylla, S. guangzhouensis and S. caprifici where the EP is at metacorpus level. However, S. hirtus n. sp. differs from S. macrophylla and S. guangzhouensis by possessing a shorter PUS and smaller spicules, and differs from S. caprifici by a shorter female stylet and smaller spicules. Schistonchus hirtus n. sp. was easily differentiated from other sequenced species by the proportion of parsimony informative changes in the partial small subunit rRNA gene (SSU) and D2/D3 expansion segments of the large subunit rRNA gene (LSU). Phylogenetic analysis with SSU sequences suggests that S. hirtus n. sp. is in a highly supported monophyletic clade with Aphelenchoides and Laimaphelenchus and is polyphyletic to other sequenced Schistonchus species. With LSU sequence data, it forms a clade with S. caprifici and they appear polyphyletic relative to S. guangzhouensis, S. centerae, S. aureus, S. laevigatus and S. virens.

In: Nematology

Abstract

Schistonchus microcarpus n. sp. was recovered from the syconia of Ficus microcarpa from Shenzhen and Guangzhou, Guangdong Province, China, during a survey of nematode biodiversity from 2007 to 2009. It is characterised by possessing the combined characters of a short post-uterine sac (PUS) (3-11 μm or <0.4 vulval body diam. (VBD) long), excretory pore located just posterior to the head but anterior to the conus level of the stylet, prominent amphids, three pairs of subventral papillae on the male tail (one pair adcloacal, one pair halfway between cloaca and tail terminus, and one pair near tail tip), unique recurved and sickleshaped spicules with finely rounded tip with cucullus, amoeboid sperm, and rounded male tail tip with or without mucron. Schistonchus microcarpus n. sp. is morphologically differentiated from all other described species in this genus by the possession of a spicule with a cucullus on the tip. Schistonchus microcarpus n. sp. was easily differentiated from other sequenced species by the partial small subunit rRNA gene (SSU) and D3 expansion segments of the large subunit rRNA gene (LSU). Phylogenetic analysis with partial SSU sequences suggests that S. microcarpus n. sp. is in a highly supported monophyletic clade with sequenced Schistonchus species except for S. hirtus. Based upon inferences using D3 LSU sequence data, it forms a clade with an undescribed species of Schistonchus ex F. benjamini from Australia and is part of a larger clade of Schistonchus that mostly share the character of an anteriorly placed excretory pore. Sequences of partial mtDNA COI (590 bp) from males of S. microcarpus n. sp. with and without a mucronate tail tip were identical, proving that these two morphotypes are conspecific.

In: Nematology

Abstract

Diplogastrellus metamasius n. sp. (Rhabditidae) was cultured from dauer juveniles recovered during dissections of the West Indian sugarcane weevil, Metamasius hemipterus (Coleoptera: Dryophthoridae), from southern Florida and Costa Rica. Morphological studies of these two isolates with light microscopy and SEM revealed many typological differences between it and the closest putative relative. Based upon molecular and mating studies, the two isolates are conspecific and are described herein as Diplogastrellus metamasius n. sp. Diplogastrellus metamasius n. sp. is characterised by stomatal structure, i.e., cheilostom with thin adradial cuticular flaps, anterior region of gymnostom ring strongly cuticularised and refractile, stegostom forming a structure resembling a 'glottoid' apparatus and possessing a movable, flap-like, dorsal tooth with small ventral ridges, oblong (elongated) median bulb in both sexes, single gonad with short (less than one vulva body diam.) postuterine sac, well developed ovary reflexed posteriorly beyond the vulva, tapered to filiform tail in both sexes, relatively large gubernaculum in males (with arcuate anterior part and pointed distal part in lateral view) and arrangement of the nine pairs of male genital papillae, especially the position of first two pairs which are located far anterior to the cloacal slit. Because of the many possibilities for homoplasy in the morphological characters possessed by the new species and described species in the 'sister' genera of Butlerius, i.e., the arrangement of male caudal papillae, and Paroigolaimella, i.e., the arrangement of cheilostomatal flaps, molecular analysis of more members of these putative clades is necessary before unambiguous generic placement of this new species is possible.

In: Nematology

Abstract

Acrostichus dauer larvae (JIII) were recovered during dissections of the palmetto weevil, Rhynchophorus cruentatus, from southern Florida, and the palm weevil, R. palmarum, from Colombia, Costa Rica and Trinidad. Based upon morphological and molecular studies, the four isolates are conspecific and are described herein as A. rhynchophori n. sp. Acrostichus rhynchophori n. sp. is characterised by narrow, flap-like dorsal tooth, female gonads not reflexed to the level of the vulva, male spicule and gubernaculum morphology, i.e., spicule with small and indistinct manubrium embedded in lamina/calomus complex, strong expansion just posterior to manubrium and smoothly curved and smoothly tapered lamina/calomus complex, and gubernaculum with claw-like anterior end in lateral view and three distal branches in ventral view. The new species is distinguished from A. superbus by morphology of the spicule and gubernaculum. Type specimens of four other Acrostichus species, originally described from bark beetles from North America, i.e., A. concolor, A. gubernatus, A. ponderosus and A. taedus, were re-examined and photo-documented.

In: Nematology

The purposes of this paper are to clarify the taxonomic status of the fig-pollinating wasp associate Schistonchus sensu lato (Nematoda: Aphelenchoididae) and to suggest directions for future research on the systematics, life history and ecology of the group. Molecular phylogenetic analyses suggest that Schistonchus s.l. is polyphyletic, and the composition of the three major clades is outlined, together with information on nematode morphology, plant host species, associated pollinating wasp species, and distribution. Biological information and collection data is presented for Schistonchus s.l. from Ficus sycones (Moracea) in Africa, Australia, Asia and Central America, and its putative phylogeny is discussed based on molecular and morphological evidence. Both wasps and figs are millions of years old and have worldwide distribution in tropical areas, i.e., opportunities for Schistonchus s.l.-like nematodes to have evolved could have occurred more than once. In addition, figs and their pollinating wasps have variable life histories, which could have provided opportunities for Schistonchus s.l. to also develop different life histories. However, these histories occur inside fig sycones and in association with wasps, which has apparently led to evolutionary convergence and extreme morphological conservatism. Diagnostic characters and their states, derived from examination of described species and morphospecies of Schistonchus s.l. and informed by molecular phylogenetic inferences, are discussed and illustrated. Schistonchus sensu stricto is redefined, and Ficophagus n. gen. and Martininema n. gen. are proposed. Schistonchus s.s. is morphologically characterised by having the excretory pore opening in the region of, or posterior to, the metacorpus; Ficophagus n. gen. by having the excretory pore opening very near the cephalic region; and Martininema n. gen. by having it opening at the anterior end of the metacorpus. Several species of Schistonchus s.s. have a labial disc, but there is no evidence of this in either Ficophagus n. gen. or Martininema n. gen.

In: Nematology