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

Purhepecha oak (Quercus purhepecha), new species of shrub oak endemic to the state of Michoacán, Mexico

NEWS - In Mexico, several Quercus shrubby species are taxonomically very problematic including 8 taxa with similar characteristics. Now researchers report the purhepecha oak ( Quercus purhepecha De Luna-Bonilla, S. Valencia & Coombes sp. nov.) as a new tomentose shrubby white oak species with a distribution only in the Cuitzeo basin in the Trans-Mexican Volcanic Belt (TMVB). Quercus Linnaeus (1753) subdivided into 2 subgenera and 8 sections of which section Quercus (white oaks) has the widest distribution in the Americas, Asia and Europe. This section is very diverse in Mexico and Central America with phylogenomic evidence indicating recent and accelerated speciation in these regions. The number of shrubby oak species in Mexico is still uncertain. De Luna-Bonilla of the Universidad Nacional Autónoma de México and colleagues found at least 3 taxa in the TMVB, specifically Quercus frutex Trelease (1924), Quercus microphylla Née (1801) and Quercus repanda Bonpland (1809). In 2016,...
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

Lesser banded hornet (Vespa affinis)

Tawon ndas or lesser banded hornet ( Vespa affinis ) are medium wasps with queens up to 30mm, males 26mm and average workers 22-25mm. The head is dark red, brown and black. Segmented stomachs are dark brown except the first and second segments are yellowish orange to brown. V. affinis has at least 10 subspecies with different color variations is V. a. alduini , V. a. alticincta , V. a. archiboldi , V. a. continentalis , V. a. hainensis , V. a. indosinensis , V. a. moluccana , V. a. nigriventris , V. a. picea and V. a. rufonigrans . Tawon ndas forages in grassy areas, farmland, forests and deserts. They eat carbohydrates such as tree sap, nectar and fruit, while proteins such as larvae, carrion, paper wasps (Polistinae) and bees (Apidae). These insects often carry meat from new dead animals and flies that perch on the carcass. Nests are built on trees and people's homes. Nests are generally elongated or pear in the tropics and oval with rounded tops in subtropical regions. ...
Read more