Description and SEM Observations of Dolichodorus marylandicus n. sp. With a Key to Species of Dolichodorus

Stephen Lewis, A. Morgan Golden

Abstract


Dolichodorus marylandicus n. sp. is described and illustrated from grass (Zoysia japonica) in College Park, Maryland. Specimens have also been collected from perennial bluegrass (Poa pratensis) pasture at Beltsville, Maryland, and from pine (Pinus sp.) in North Carolina. This new species is related to D. heterocephalus Cobb, D. similis Golden, and D. aestuarius Chow & Taylor. Females are distinct in having a longer styler and shorter body length than D. aestuarius. The excretory pore is at the level of the isthmus or slightly posterior and the tail is abruptly reduced in diameter, tapering to an acuminate terminus. The tails of D. similis and D. heterocephalus conically taper to a median point, with D. similis having an especially long tail. D. marylandicus does not possess the rounded, sclerotized accessory structures adjacent to the vulva observed in lateral views of D. similis and D. heterocephalus. SEM observations of D. heterocephalus and D. marylandicus revealed details of the head of males and females, and species difference in shape of the oral disc. Key words: taxonomy, morphology, Doliehodorus, awl nematode, new species, SEM ultrastructure, grass, Zoysia japonica, Poa pratensis, Pinus, pine.

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