Two New Free-Living Marine Nematode Species of the Genus <i>Haliplectus</i> Cobb, 1913 (Haliplectidae) from Mangroves of Shenzhen, Guangdong Province, China

Abstract

This study presents two new free-living marine nematodes, Haliplectus major sp. nov. and Haliplectus futianisus sp. nov., from a mangrove reservation in Shenzhen, China. Haliplectus major sp. nov. can be distinguished by its total body length of 1615–1998 µm; a cuticle annulated with eight rows of cuticle pores; amphidial fovea at 9–12 µm from the anterior end; a bipartite basal bulb with striated valve plates in both sexes; five to seven closely spaced precloacal supplements in males; a didelphic reproductive system in females, with the vulva at 49.64–52.37% of body length; and sexual dimorphism in tail shape, arcuate-conoid and 2.3–3.2 times anal body diameter long in males and elongate-conid and 3.5–4.2 times anal body diameter long in females. Haliplectus futianisus sp. nov. is characterized by a total body length of 574–655 µm; a cuticle annulated with eight rows of cuticle pores; amphidial fovea at 8–11 µm from the anterior end; a monopartite basal bulb with unstriated valve plates in both sexes; an absence of precloacal supplements in males; and a didelphic reproductive system in females, with the vulva at 42.33–45.63% of body length. The identification was confirmed by analyzing morphological characteristic and 18S rRNA gene sequences. The maximum likelihood (ML) topology was regarded as morphological evidence of H. major sp. nov. and H. futianisus sp. nov. being two distinct species.

Keywords

• free-living marine nematode
• <i>Haliplectus</i>
• new species
• morphology
• 18S rDNA