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J Nematol

Title:		Phylogenetic implications of phasmid absence in males of three genera in heteroderinae
Author(s):		Carta LK; Baldwin JG;
Address:
Journal Title:		J Nematol
Year:		1990
Volume:		22
Issue:		3
Page Number:		386 - 394
DOI:
ISSN/ISBN:		0022-300X (Print) 0022-300X (Linking)
Abstract:		"Absence of the phasmid was demonstrated with the transmission electron microscope in immature third-stage (M3) and fourth-stage (M4) males and mature fifth-stage males (M5) of Heterodera schachtii, M3 and M4 of Verutus volvingentis, and M5 of Cactodera eremica. This absence was supported by the lack of phasmid staining with Coomassie blue and cobalt sulfide. All phasmid structures, except the canal and ampulla, were absent in the postpenetration second-stage juvenile (J2) of H. schachtii. The prepenetration V. volvingentis J2 differs from H. schachtii by having only a canal remnant and no ampulla. This and parsimonious evidence suggest that these two types of phasmids probably evolved in parallel, although ampulla and receptor cavity shape are similar. Absence of the male phasmid throughout development might be associated with an amphimictic mode of reproduction. Phasmid function is discussed, and female pheromone reception ruled out. Variations in ampulla shape are evaluated as phylogenetic character states within the Heteroderinae and putative phylogenetic outgroup Hoplolaimidae"
Keywords:		Cactodera eremica Heterodera schachtii Heteroderinae Verutus volvingentis ampulla anaphimixis cell death parallel evolution parthenogenesis phasmid phylogeny ultrastructure;
Notes:		"PubMed-not-MEDLINECarta, L K Baldwin, J G eng Poland 1990/07/01 J Nematol. 1990 Jul; 22(3):386-94"