Skip to main content

Porous roundworm (Labronema porosum) and Mount Bidoup roundworm (Labronema bidoupense) from Vietnam

Porous roundworm (Labronema porosum) and Mount Bidoup roundworm (Labronema bidoupense) from Vietnam

NEWS - Researchers have established porous roundworm (Labronema porosum) and Mount Bidoup roundworm (Labronema bidoupense) from natural habitat in Vietnam as new species based on morphological and molecular characters (18S rDNA and 28 rDNA). The two new taxa belong to the group of L. ferox Thorne 1939 with a length of 1.5-2.5 mm, odontostyle 31-39 μm and a lip region offset by a constriction.

Labronema Thorne 1939 is a large and diverse dorylaimid genus with complex taxonomy. The study also shows that the population from Vietnam previously identified as L. glandosum Rahman, Jairajpuri, Ahmad & Ahmad 1986 actually represents L. porosum.

L. porosum gets its nickname reflecting its prominent ventral and lateral body pores. This species is 1.6-2.25 mm long, odontostylic (32-37 μm), weakly angled and offset by a narrowed lip area, 21-24 μm wide, there is a cuticular fold on the dorsal side of the stoma, the uterus is not differentiated, the vulva is longitudinal (V = 48.5-59%). the tail is short and rounded (25-30 μm, c = 53-90, c’ = 0.5-0.6).

This new species resembles L. andrassyi Gagarin 1992, L. brevicauda Furstenberg Heyns & Swart 1993, L. gerlachi Andrássy 2011, L. glandosum and L. obesum Thorne 1974, but can be distinguished from all of them by the distinctive cuticular fold on the dorsal side of the stoma.

L. bidoupense is nicknamed after Mount Bidoup. This species is characterized by a length of 1.59-2.04 mm, a lip area balanced by a deep constriction with a width of 25-28 μm, odontostyle length 37.5-39 μm, uterus complex (tripartite), longitudinal vulva (V = 54-57%), short and rounded tail (26-31 μm, c = 57.8-77.2, c’ = 0.5-0.6).

Males with spicules 68-83 μm long, 5-6 times longer than the ventromedian supplements which are wide and connected in number 13-15, leaf-shaped lateral cuts. This species resembles L. andrassyi, L. brevicauda, L. gerlachi, L. glandosum, L. obesum and L. porosum.

An integrative taxonomic approach for L. porosum and L. bidoupense contributes to the knowledge of the large and complex genus Labronema. Both species are morphologically and genetically very close to form a well-supported clade with the type species and L. vulvapapillatum or Vakil Kandi population (Iran).

Other populations identified as L. vulvapapillatum from the Netherlands and Kerman Province (Iran) clustered together in the 18S rDNA tree and were closely related to the clade. Clearly, L. vulvapapillatum populations from the Netherlands and Kerman Province are not conspecific with the Vakil Kandi population.

28S rDNA sequencing of two Labronema populations from Du Gia Nature Reserve (Bac Me District, Ha Giang Province) and Cuc Phuong National Park (Ninh Binh Province) confirmed that the population previously recorded as L. glandosum from Cuc Phuong National Park is identical to L. porosum.

It is very difficult to assess the phylogenetic relationships of Labronema with other genera using an integrative approach due to the very low number of species studied, also affecting the reconstruction of the evolutionary history of dorylaimid groups at higher taxonomic levels.

Original research

Vu TTT, Elshishka M, Nguyen AD, Le TML, Mladenov A, Peneva V (2024). Two new species of genus Labronema Thorne, 1939 (Nematoda, Dorylaimidae) from natural parks of Vietnam with an identification key to the species with a medium-sized odontostyle. ZooKeys 1215: 1-26, DOI:10.3897/zookeys.1215.128183

Dlium theDlium
Labels:

Popular Posts

Ralph Holzenthal caddisfly (Rhyacophila lignumvallis) from Corsica in Rhyacophila tristis (Schmid 1970) group

NEWS - Ralph Holzenthal caddisfly ( Rhyacophila lignumvallis Graf & Rázuri-Gonzales, sp. nov.) from the island of Corsica (France) was established as a new species in the Rhyacophila tristis (Schmid 1970) group based on morphological analysis and the mitochondrial cytochrome c oxidase subunit I (mtCOI), including sequences from 16 of the 28 species in the group. Rhyacophila Pictet 1834 with 814 living and 30 fossil species is the largest genus of caddisflies in the world, distributed mainly in the northern hemisphere, but also in temperate and tropical India and Southeast Asia. One of the groups is the R. tristis group in the branch Rhyacophila invaria . R. lignumvallis is most similar to Rhyacophila pubescens Pictet 1834, Rhyacophila tsurakiana Malicky 1984, Rhyacophila ligurica Oláh & Vinçon 2021, Rhyacophila harmasa Oláh & Vinçon 2021 and Rhyacophila abruzzica Oláh & Vinçon 2021. However, R. lignumvallis differs in the shape of the X tergum, the dorsal arm ...
Read more

Pong pong (Cerbera odollam)

Bintaro or pong pong ( Cerbera odollam ) is a plant species in Apocynaceae, a medium-sized tree with circular branches around the trunk, non-woody, gummy white, highly poisonous and the leaves are used for bioinsecticide, seeds are used as biodiesel material and often used for ornamental plants. C. odollam is less than 17 meters tall, grows upright, has low and sideways branches to form an umbrella canopy, the bark is thin and dark brown, lots of white sap, the whole stem has traces of circular petioles. Leaves have large stalks with thick strands, inverted or elongated ovoid, 4.5-7 cm wide, 15-30 cm long, blunt base, sharp tip, a large bone in the middle with sideways veins, dark green and shiny upper surface, the lower surface is lighter. The white flower is located at the end of the stem and long stalk. Trumpet-shaped crown with five tongues, tube 1.5-2 cm long, white with yellow tunnels and a few yellow hairs. The fruit is round, green in color with a green fibrous shell enclosi...
Read more

Golden trumpet (Allamanda cathartica)

Allamanda or golden trumpet ( Allamanda cathartica ) is a species of plant in Apocynaceae, evergreen, woody shrub, upright, up to 2 meters high, old stems are brown due to wood formation and young shoots are green. The leaves have pointed tips, rough surfaces, 6-23 cm long and gathered in 3-4 strands. The flowers are yellow and shaped like trumpets, 9 cm long and 5-7.5 cm in diameter. This species grows around rivers or open areas that are exposed to lots of sunlight with sufficient rain and high humidity throughout the year. This plant is unable to grow in saline or too alkaline soil and cannot withstand low temperatures. A. cathartica grows well and produces flowers in full sun intensity without obstruction. This species grows well in sandy soil, rich in organic matter and well aerated. The right climate for growth is a tropical climate. The native habitat is at an elevation of 0-700 meters, rainfall 1000-2800 mm/year. Flowers grow year-round in many habitats, propagating by seed an...
Read more