Beiträge zur Kenntnis pflanzenparasitischer Nematoden

Sommer

2014

A new species of diplogastrid nematode, Levipalatum texanum n. gen., n. sp., was isolated from scarab beetles (Coleoptera: Scarabaeidae) in Texas and baited from soil in Virginia, USA. Levipalatum n. gen. is circumscribed by stomatal and pharyngeal morphology, namely a long, hooked dorsal tooth connected to a 'palate' projecting anteriad and mediad, subventral telostegostomatal ridges of denticles, and the dorsal radius of the pharynx bulging anteriad. The males of the new species are distinguished from most other Diplogastridae by the frequent presence of ten pairs of genital papillae. Phylogenetic relationships inferred from 11 ribosomal protein-coding genes and a fragment of the small subunit rRNA gene strongly support L. texanum n. gen., n. sp. to be a sister group to Rhabditolaimus, which lacks all the stegostomatal and pharyngeal characters diagnosing the new genus. The new species expands comparative studies of the radiation of feeding morphology that are anchored on the model organism Pristionchus pacificus. The phylogenetic position of L. texanum n. gen., n. sp. indicates a new case of convergent evolution of hermaphroditism in Diplogastridae.

Section: Discussionmentioning

confidence: 99%

Levipalatum texanum n. gen., n. sp. (Nematoda: Diplogastridae), an androdioecious species from the south-eastern USA

Ragsdale

Sommer

2014

“…Stomatal dimorphism (trophic di-or polymorphism) has been reported in several diplogastrid genera including rather basal ones, e.g., Koerneria, Pristionchus Kreis, 1932, Acrostichus Rahm, 1928, Neodiplogaster Cobb, 1924and Micoletzkya Weingartner, 1955(see Baldwin et al, 1997Sudhaus & Fürst von Lieven, 2003;Mayer et al, 2009;Kiontke & Fitch, 2010;Kanzaki et al, 2011) and is considered to be an adaptation to unstable environmental conditions, i.e., the typical propagative stage often manifests the stenostomatous form which feeds on bacteria, whereas the eurystomatous form, assumed to be predatory or omnivorous, occurs under unfavourable conditions, e.g., old culture plates in Acrostichus and Pristionchus spp. {e.g., Giblin & Kaya, 1984;Baldwin et al, 1997;Hong & Sommer, 2006).…”

Section: Stomatal Dimorphism In Parasitodiplogastermentioning

confidence: 99%

Description of Parasitodiplogaster pharmaconema n. sp. and redescription of P. maxinema from Ficus maxima Mill. (Moraceae)

Giblin-Davis

et al. 2013

BRILL Nematology 15 (2013) 957-974 Nematology brill.com/nemy Description of Parasitodiplogaster pharmaconema n. sp. and redescription of P. maxinema from Ficus maxima Mill. (Moraceae) Summary -Parasitodiplogaster species associated with Eicus maxima were surveyed at the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama. Phase B-D syconia were collected from different trees and dissected in distilled water. Because there were different nematode stomatal and male morphotypes observed in a single sycone, nematodes isolated from each fig were observed to determine general morphotype class and stored individually in DNA extraction buffer for accurate morpho/molecular pairing. Additional voucher nematodes were gently heat-treated and fixed in formalin and processed into permanent mounts in dehydrated glycerin for more rigorous morphological examination. The survey yielded two different Parasitodiplogaster species: P. maxinema and P. pharmaconema n. sp. Several morphological characters, e.g., two long and stick-like teeth in the metastegostom, and stomatal dimorphism (presence of eurystomatous form) which were not previously described, were observed in P. maxinema and are ascribed hereto this species. Parasitodiplogaster pharmaconema n. sp. is morphologically similar to P. maxinema and P. yoponema but can be distinguished from these species based upon stomatal morphology, spicule and gubernaculum morphology, and number and arrangement of male genital papillae.

“…Consequently, intensive sampling of potential insect hosts has recently revealed diverse new taxa in the family (Kanzaki et al, 2009(Kanzaki et al, , 2012a. Scarab beetles (Coleóptera: Scarabaeidae) in particular are hosts to many diplogastrid species, especially in Pristionchus Kreis, 1932(Herrmann et al, 2006Mayer et al, 2007Mayer et al, , 2009Rae et al, 2008;Kanzaki et al, 2012aKanzaki et al, , 2013, but also in Diplogasteroides de Man, 1912, Koerneria Meyl, 1960, Mononchoides Rahm, 1928, Rhabditidoides Rahm, 1928, and Tylopharynx de Man, 1876(Mayer et al, 2009. new genus of Diplogastridae, Sudhausia n. gen., based on its unique stomatal morphology, sex-specific characters, and a suite of unusual developmental traits.…”

mentioning

confidence: 99%

Sudhausia aristotokia n. gen., n. sp. and S. crassa n. gen., n. sp. (Nematoda: Diplogastridae): viviparous new species with precocious gonad development

Herrmann

Ragsdale

et al. 2013

Two new species of diplogastrid nematodes, Sudhausia aristotokia n. gen., n. sp. and S. crassa n. gen., n. sp., were isolated from dung beetles (Coleoptera: Scarabaeidae) in Ghana and South Africa, respectively. Sudhausia n. gen. is circumscribed by stomatal morphology, namely the presence of a tube-shaped gymnostom, a pair of conical subventral denticles in the metastegostom, and a disk-like telostegostom bearing minute conical denticles. Other characters distinguishing the new genus are the presence of a bursa in the male and a vulva lined anteriorly and posteriorly by columns of sac-like cells. The two new species, both of which are hermaphroditic, are distinguished from each other by spicule and gubernaculum morphology, male papillae arrangement, bursal shape, vaginal morphology, and phasmid position. A suite of unusual developmental traits that distinguishes Sudhausia n. spp. includes maturation of the gonad and development of juvenile progeny before moulting to adulthood, a two-fold increase in embryo size during development, and constitutive vivipary. A phylogeny inferred from 11 ribosomal protein-coding genes and a fragment of the small subunit rRNA gene show Sudhausia n. gen. to be divergent from other sequenced diplogastrid taxa, including those characterised by a tube-like stoma. The two new species represent useful new reference points for the study of feeding-structure evolution in Diplogastridae.