Skip to main content

Foliaceous coastal worm (Thoracophelia foliformis) found in intertidal zone of Yellow Sea, South Korea

Foliaceous coastal worm (Thoracophelia foliformis) found in intertidal zone of Yellow Sea, South Korea

NEWS - Foliaceous coastal worm (Thoracophelia foliformis sp. nov.) was discovered in the intertidal zone as the first species of the genus from the Yellow Sea, Korea. The new species is closely related to T. dillonensis (Hartman, 1938) from California and T. ezoensis Okuda, 1936 from Japan because it has pectinate branchiae.

The new specific epithet is derived from the leafy ventral midplate shape of the pygidium. The name is a combination of the Latin words folium (meaning ‘leaf’) and formis (meaning ‘form’). The Korean name is Yip-sa-gwi-Keun-yo-jeong-get-ji-reong-yi (잎사귀큰요정갯지렁이). The specimen was collected from the upper intertidal zone consisting of sand or muddy sand in the Yellow Sea of South Korea.

Although the number of branchial filaments in well-developed branchiae varies (12-15), there is no variation in the number of pairs of branchiae (15 pairs) or the first chaetiger containing branchiae (chaetiger 14) among specimens. Oocytes are contained in a coelomic cavity about 0.1 mm in diameter, visible through the transparent body wall.

The annulation of each segment has a weak lineal staining and is thicker in the mid-dorsal abdominal region. The most posterior segments and the mid-ventral plate of the pygidium are intensely stained. A deep, large circular spot is present at the base of each branchiae anteriorly. The prostomium is weakly stained on the lateral side.

To date, 18 species have been described in Thoracophelia. The new species differs from the others in the shape of the branchiae and pygidium. By having pectinate branchiae, T. foliformis resembles T. dillonensis and T. ezoensis.

However, T. foliformis differs from T. dillonensis in having wrinkled branchiae with fewer branchial filaments (12-15 vs. 15-20) at full development and a mid-ventral plate on the pygidium. T. foliformis differs from T. ezoensis in the number of branchiae pairs (15 vs. 19) and the presence of a mid-ventral plate on the pygidium.

The new species also differs from T. minuta (Jimi, 2021) in having a small body and simple hemispherical branchiae without ciliated areas. The new species differs from T. japonica in having palmatifid branchiae with 3-7 filaments and a pair of lateral transverse rows of cone-shaped cirri on chaetiger 10 instead of a lateral ridge.

The new species also differs from T. yasudai and T. arctica in that both species have dichotomously divided branches. The new species has bifid or trifid branchiae, which is different from the other 12 Thoracophelia species. The new species differs from T. williamsi in having pectinate branchiae (vs. bifid and trifid branchiae with pinnate dorsal filaments).

In COI, the minimum interspecific variation between the new species and related species was 14.2% for T. minuta. However, the new species differs from T. minuta in the shape of the branchiae (pectinate vs. hemispherical). The new species is most closely related to T. mucronata with 0.2% and 3.6% differences in 18S and 28S rDNA, respectively, but the new species differs from T. mucronata in having pectinate branchiae rather than bifid.

In the tree based on 18S and 28S rDNA sequences, the Opheliidae are grouped into two clades of the subfamilies Ophelininae and Opheliinae based on the sequences of several gene regions assembled. Thoracophelia species form a monophyletic group including the new species with high support values (ML = 81%, BI = 0.95).

The new species is sister to two clades of Japanese and American Thoracophelia species, although morphological features reflecting this phylogenetic relationship have not been identified. The 18S and 28S rDNA sequence trees showed similar results to the assembled nuclear gene results.

Original research

Lee H-E, Lee GH, Min G-S (2024). A new species of Thoracophelia (Annelida, Opheliidae) from the Yellow Sea of South Korea. Biodiversity Data Journal 12: e129526, DOI:10.3897/BDJ.12.e129526

Dlium theDlium
Labels:

Popular Posts

Bugang (Clerodendrum calamitosum)

Bugang ( Clerodendrum calamitosum ) is a species of plant in the Lamiaceae family. It is an erect shrub, growing up to 1 meter tall, with cylindrical, green stems and white hairs. The leaves are opposite. The leaf blade is oval, wavy, with a central main vein with numerous pinnate minor veins, and serrated margins. The leaves are up to 9 cm long and 7 cm wide. The petiole is up to 2 cm long. The flowers are star-shaped, white, up to 3 cm in diameter and up to 6 cm in total length. The fruit is round, dark green, turning black when ripe. TAXON Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Lamiales Family: Lamiaceae Subfamily: Ajugoideae Genus: Clerodendrum L. in Sp. Pl.: 637 (1753) Species: Clerodendrum calamitosum L. in Mant. Pl. 1: 90 (1767) HETEROTYPIC SYNONYMS Clerodendrum fastigiatum (W.Hunter ex Ridl.) H.J.Lam in Verben. Malay. Archip.: 317 (1919) Volkameria alternifolia Burm.f. in Fl. Indica: 137 (1768) Volkameria fastigiata W.Hunter...
Read more

Common sun skink (Eutropis multifasciata)

Kadal kebun or bengkarung or Mabuya multifasciata or common sun skink ( Eutropis multifasciata ) is a species of lizard in Scincidae, has a pattern of faint lines extending to the sides of the body, measuring 18 to 22 cm in length with a tail length of about 60% of the overall body and more many live on the ground. E. multifasciata has a sharp head with a very short neck and a square cross section. The upper part is dark brown or shiny grayish brown with a golden body side especially near the neck. Sometimes also decorated with small pale spots on the back. The lower neck is light brown and the abdomen to the anus is pale brown. The muzzle is reddish, the tail is the same color as the body, decorated with a faint dark line on the sides. The arms are also the same color as the upper body. Common sun skinks usually live on the edge of forests, gardens, rice fields and human settlements. They spend most of their time on the ground, usually in crevices and rocky cliffs as a place t...
Read more

Durian (Durio zibethinus)

Durian ( Durio zibethinus ) is a species of tropical plant in Malvaceae, an annual tree, everlasting green but there are certain times to grow new leaves after the fruiting period is over, popularly called "king of fruit" and considered a controversial fruit where many people like, but some others are even fed up with the scent. D. zibethinus grows to 25-50 m, reddish brown bark and irregular peeling, leafy and stretched canopy. The leaves are oval shaped to lanceolate, 10-15x3-4.5 cm, sitting alternately, stemmed, taper or blunt base and taper-pointed sloping, bright green upper side, the lower side covered with silver or golden scales. Flowers and fruit Flowers appear directly on the trunk or old branches at the proximal, clustered in panicles containing 3-10 florets or flat-shaped florets. Rounded flower buds, 2 cm in diameter and long stem. Tubular petals, 3 cm long, additional petals split into 2-3 round lobes. Crown shaped spatula with a length of 2 times the ...
Read more