Tripylina Brzeski, 1963

Zhao, Zeng Qi, 2009, A review of the genus Tripylina Brzeski, 1963 (Nematoda: Triplonchida), with descriptions of five new species from New Zealand, Zootaxa 2238, pp. 1-24 : 4-5

Genus Tripylina Brzeski, 1963

Synonym. Abunema Khera, 1971 (see Andrássy 1985, 2007)

Description (after Brzeski 1963). Body length 0.8–1.8mm. Cuticle smooth with numerous pores, thin, and not annulated. Six longer and four shorter cephalic setae in a single whorl. Stoma with dorsal tooth in a stomatal chamber, with two subventral denticles anterior or posterior to it. Phanyngeal-intestinal valve composed of three glands around anterior portion of intestine. Female genital organ mono-prodelphic, without post-vulval uterine sac, reflexed; vagina with internal sclerotized pieces; V 60 –80. Males very rare. Spicules narrow, sickle-shaped. Supplements confined to precloacal region. Tail in both sexes short, anteriorly conical and posteriorly cylindrical, strongly bent.

Type species. Tripylina arenicola (de Man, 1880) Brzeski, 1963.

Diagnosis and relationships. The mono-prodelphic female genital system characterizes this genus and differentiates it from both Tripyla Bastian, 1865 and Tripylella Brzeski & Winiszewska-Ślipińska, 1993 .

Etymology. Tripylina is a diminutive of Tripyla .

Remarks. There is no consensus on generic level classification in the family Tripylidae based on morphological characters, despite many morphological studies in the last 20-30 years. Tsalolikhin (1983) included four genera: Tripyla Bastian, 1865 , Paratripyla Brzeski, 1964 , Trischistoma Cobb, 1913 and Tripylina . Brzeski and Winiszewska-Ślipińska (1993) partly accepted Tsalolikhin and assigned Tripylina , Tripyla Bastian, 1865 and Tripylella Brzeski & Winiszewska-Ślipińska, 1993 to the family. Zullini (2006) largely accepted the classification of Brzeski and Winiszewska-Ślipińska (1993), but provisionally included Trischistoma Cobb, 1913 , Tobrilia Andrássy, 1967 and Abunema Khera, 1971 because those genera had no alternative placements. More recently, Andrássy (2007) considered the family Tripylidae to comprise three subfamilies (Tripylinae de Man, 1876, Trischistomatinae Andrássy, 2007 and Tobriliinae Andrássy, 2007), and proposed placing Tripylina , Tripyla and Tripylella into the subfamily Tripylinae; Trischistoma into Trischistomatinae and Tobrilia into Tobriliinae.

Molecular taxonomy has been applied in many areas of nematode systematics for more than a decade. However, this is the first attempt to study extensively in the family Tripylidae by molecular phylogenetic methods. This analysis, including the New Zealand tripylids and previously published nematode SSU and LSU sequences from GenBank indicated the following ( Fig. 1 & 2 ).

1) Genetically T. tearoha sp. nov., T. tamaki sp. nov. and T. manurewa sp. nov. are different species.

2) T. tearoha sp. nov. and T. tamaki sp. nov. are closely related and some evolutionary distance separates them from T. manurewa sp. nov..

3) The family Tripylidae may contain five to six groups ( Tripyla with long tails, Tripyla with long cephalic setae, Tripyla with short cephalic setae, Tripylina and Trischistoma ) ( Zhao & Thomas 2009).

4) Tripylina and Trischistoma are not closely related to Tripyla , the type genus of the family Tripylidae .

5) The relationships among genera within Tripylidae are not well resolved.

6) The genus Tripylina appears monophyletic with respect to Trischistoma and more closely related to the Enoplida than to the Triplonchida , a result consistent with the results of Meldal et al. (2007).

The systematic position of the genera in the family Tripylidae is discussed in Zhao & Thomas (2009).

Figures

FIGURE 1. Bayesian tree inferred from SSU gene DNA sequences. Posterior probabilities exceeding 50 % are given on appropriate clades. Nematode species, GenBank numbers, locations are listed for each taxon if known.

FIGURE 2. Bayesian tree inferred from LSU gene DNA sequences. Posterior probabilities exceeding 50 % are given on appropriate clades. Nematode species, GenBank numbers, locations are listed for each taxon if known.