Morphological and molecular characterisation of Panagrellus spp. (Cephalobina

Panagrolaimidae): Taxonomic status and phylogenetic relationships

S Patricia Stock, Steven A. Nadler

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The genus Panagrellus currently comprises 12 known species. These nematodes have a worldwide distribution and have been found in a variety of habitats such as slime flux, thermal springs, insect frass and spoiled cider. Diagnosis of Panagrellus species is rather problematic since few morphological features can be used to discriminate between species and the original publications do not indicate the number of specimens measured and lack standard descriptions of variance. In this study we review the taxonomic status of several species from this genus combining classical morphological data and molecular sequences. Eleven live isolates and fixed material from currently available type specimens representing six Panagrellus species were included. Morphological analysis included the examination of qualitative and quantitative characters of males and females. The taxonomic utility of morphometric data was evaluated by means of multivariate statistics (principal component and canonical discriminant analyses). Phylogenetic inference was based on analysis of nucleotide sequences from the LSU rDNA gene and morphological characters. Parsimony tree topologies inferred from nucleotide datasets strongly supported monophyly of the P. dubius isolates, but not the P. redivivus isolates. Phylogenetic interpretation of these rDNA sequence data suggests that both the P. redivivus and P. dubius isolates each include more than a single species. Only two of the 15 morphological characters evaluated were variable within the ingroup taxa. A long spicule bifurcation length maps on the combined evidence trees as a putative synapmorphy for P. dubius, whereas male D% was homoplastic within isolates of that species. The diagnosis of the genus Panagrellus is emended.

Original languageEnglish (US)
Pages (from-to)921-938
Number of pages18
JournalNematology
Volume8
Issue number6
DOIs
StatePublished - Dec 2006

Fingerprint

Panagrolaimidae
Panagrellus
phylogenetics
phylogeny
ciders
frass
hot springs
type collections
quantitative traits
topology
monophyly
multivariate analysis
nucleotides
Nematoda
nucleotide sequences
type specimen
spicule
insects
thermal spring
bifurcation

Keywords

  • 28S rDNA
  • Evolutionary relationships
  • Free-living nematodes
  • Molecular
  • Morphology
  • Phylogeny
  • Systematics
  • Taxonomy

ASJC Scopus subject areas

  • Animal Science and Zoology

Cite this

Morphological and molecular characterisation of Panagrellus spp. (Cephalobina : Panagrolaimidae): Taxonomic status and phylogenetic relationships. / Stock, S Patricia; Nadler, Steven A.

In: Nematology, Vol. 8, No. 6, 12.2006, p. 921-938.

Research output: Contribution to journalArticle

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