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

Humpback whales (Megaptera novaeangliae) manufacture bubble-nets as tools to increase prey intake

NEWS - Humpback whales ( Megaptera novaeangliae ) create bubble net tools while foraging, consisting of internal tangential rings, and actively control the number of rings, their size, depth and horizontal spacing between the surrounding bubbles. These structural elements of the net increase prey intake sevenfold. Researchers have known that humpback whales create “bubble nets” for hunting, but the new report shows that the animals also manipulate them in a variety of ways to maximize catches. The behavior places humpbacks among the rare animals that make and use their own tools. “Many animals use tools to help them find food, but very few actually make or modify these tools themselves,” said Lars Bejder, director of the Marine Mammal Research Program (MMRP), University of Hawaii at Manoa. “Humpback whales in southeast Alaska create elaborate bubble nets to catch krill. They skillfully blow bubbles in patterns that form a web with internal rings. They actively control details such ...
Read more

Asian palmyra palm (Borassus flabellifer)

Asian palmyra palm ( Borassus flabellifer ) is a species of Arecaceae , palm, sturdy, single-stemmed, cylindrical shape, growing 15-30 meters tall and with a trunk diameter of about 60 cm. The leaves are clustered at the tip of the trunk, forming a rounded crown . The leaf blade resembles a round fan , up to 1.5 meters in diameter. The leaflets are 5-7 cm wide, and the underside is whitish with a waxy coating. The leaf stalk is up to 1 meter long, with a broad, black midrib at the top and a row of two-pointed spines . The inflorescence is borne on a cob, 20-30 cm long, and the stalk is about 50 cm long. The fruits are clustered in clusters of about 20, round, 7-20 cm in diameter, with a brownish-black outer skin and yellow flesh on the inside. The fruit has three seeds in a thick, hard shell. Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Liliopsida Order: Arecales Family: Arecaceae Subfamily: Coryphoideae Tribe: Borasseae Subtribe: Lataniinae Genu...
Read more

Javan mocca or Javan slender caesar (Amanita javanica)

OPINION - Javan mocca or Javan slender caesar ( Amanita javanica ) is a mysterious fungus species and has been enigmatic since it was first reported by Boedijn in 1951 and after that no explanation or reporting of specimens is believed to be the same as expected. Boedijn (1951) described A. javanica which grew on Java island as having the characteristics covered in the Amanita genus. Corner and Bas in 1962 tried to describe Javan mocca and all species in Amanita based on specimens in Singapore. Over time some reports say that they have found A. javanica specimens in other Southeast Asia including also China, Japan, India and Nepal. But there is no definitive knowledge and many doubt whether the specimen is the same as described by Boedijn (1951). I was fortunate to have seen this species one afternoon and soon I took out a camera for some shots. In fact, I've only met this mushroom species once. Javan mocca is an endangered species and I have never seen in my experience in...
Read more