A study of intertidal habitats on Jejudo Island, Korea led to the identification of two new species, Desmoscolex (Desmoscolex) jejuensis sp. nov. and Desmoscolex (Desmoscolex) longispiculatus sp. nov., belonging to the subgenus Desmoscolex. Desmoscolex (D.) jejuensis sp. nov. is distinguished by the presence of 18 main rings, with males missing the 8th, 10th, and 14th subventral setae with the 2nd and 15th setae shifted laterally. In females, the 6th, 8th, 10th, and 14th subventral setae are absent. Conversely, D. (D.) longispiculatus sp. nov. exhibits 17 main rings with a typical somatic setae arrangement along with notably elongated spicules and the 14th and 15th subventral setae shifted laterally or slightly subdorsally. Both species are characterized by relatively long and slender cephalic setae. Detailed illustrations and high-magnification micrographs were produced using differential interference contrast (DIC) microscopy and scanning electron microscopy (SEM) to facilitate morphological comparisons between these new species and related taxa. Furthermore, a comparative trait table and a pictorial key are provided to clearly differentiate these new species from morphologically similar taxa. These findings contribute to the understanding of nematode biodiversity and contribute to the broader knowledge of Desmoscolex diversity in Korean coastal ecosystems.

This study was conducted to collect data from various regions of Jejudo Island, Korea to establish a more accurate and complete academic listing of mushrooms on the island by identifying and organizing them using base sequence analysis. The investigation was performed over five years, from 2019 to 2023, and included a total of nine sites in the southern, western, and eastern areas of Jejudo Island. In total, 481 unique mushroom varieties were collected during the study. These mushrooms included 387 specimens that were classified into 6 classes, 18 orders, 55 families, 118 genera, and 201 species, and 94 unclassified specimens for which the precise species was not known. The collected mushrooms classified by ecotype consisted of 148 species of saprophytes, 47 species of symbionts, and 6 species of parasites. Differences in occurrence patterns were also observed depending on topographical characteristics and vegetation. Finally, three climate-sensitive biological indicator species and two candidate species were also collected, as well as the tropical mushroom Macrocybe gigantea. This study identified 91 species of mushrooms that were previously unreportedon the Jejudo Island. According to the current findings and those previously reported, 7 classes, 26 orders, 123 families, 399 genera, and 1,102 species of mushrooms have been compiled on Jejudo Island to date.

Saturnia (Rinaca) jonasii Butler, 1877 is distributed in Japan, including Tsushima Island and Taiwan, whereas S. boisduvalii Eversmann, 1846 is distributed in northern areas, such as China, Russia, and South Korea. In the present study we found that the specimens from Mt. Hallasan on Jejudo, a southern remote offshore island, were S. jonasii, rather than S. boisduvalii based on morphology, DNA barcode, and nuclear elongation factor 1 alpha (EF-1α) sequences. The major morphological differences between the two species included the shape of wing pattern elements of fore- and hindwings and male and female genitalia. A DNA barcode analysis of the sequences of the Jejudo specimens and S. boisduvalii, along with those of Saturnia species obtained from a public database showed a minimum sequence divergence of 4.26% (28 bp). A phylogenetic analysis also showed clustering of the Jejudo specimens with S. jonasii, separating S. boisduvalii (Bayesian posterior probability = 0.99). The EF-1α-based sequence and phylogenetic analyses of the two species from Jejudo Island and the Korean mainland showed the uniqueness of the Jejudo specimens from S. boisduvalii collected on the Korean mainland, indicating distribution of S. jonasii on Jejudo Island in South Korea, instead of S. boisduvalii.

A sea urchin was collected from 140 m deep at Gapado which is nearby Moseulpo in Jejudo Island, Korea on 30 June 2010. This specimen was classified as Echinolampas koreana H.L. Clark 1925, belonging to family Echinolampadidae of order Echinolampadoida based on its morphological characteristics. This order and lower categories are newly recorded from Korea. Distinct morphological characters of this species are as follows: test is relatively high. Abactical system has four large genital pores. Periproct is slightly sunken and situated below equator line. Peristome is very small and rather deeply sunken. Tridentate and ophiocephalous pedicellariae are present. Color in alcohol is light purple. These morphological characters are re-described with illustrations.

In 2005, an unrecorded bryozoan, Bantariella sp., invading on black corals was observed at Munseom in Jejudo Island. An intensive study was performed in the portion of 180 m width and 10~30m deep of Hangae-chang at Munseom during the period from Ja

This study focuses on the fauna, seasonal prevalence and altitudinal distribution of the flies from March to November, 2008 in Mt. Hallasan, Jejudo Island, Korea. The fauna of flies was 39 species belonging to 5 Families which consist of 12 Calliphoridae, 19 Muscidae, 5 Sarcophagidae, 1 Dryomyzidae 1, Scathophagidae and 1 Anthomyiidae. The total number of flies collected was 21,605 with sex ratio of 57.98% in Mt. Halla. The ratio is higher than that of the residential area and other mountain survey sites. The average number of per trap individuals collected on the trapping day is 267, which is similar with the average of Mts. Jiryong, Juwang, Palgong and Gumo. The five dominant species showed a distinctive seasonal prevalence of 92.6% of the total flies: Chrysomyia pinguis (34.2%), Calliphora lata (25.3%), Hydrotaea dentipes(23.1%), Fannia scalaris (5.1%), and Lucilia caesar (4.9%). The seasonal prevalence of the flies was from the beginning of March to the end of November, and the highest peak time of the whole flies, males and females were different respectively. In the similarity index of the flies collected in different altitude, that of between 1,000 meters and 1,500 meters was the highest among the indices of 500 meters and above 1,000 meters. The index at each altitude was above 80% because of the same area. The diversity index of fly species was between 0.00 and 0.88 through altitudinal traps monthly. The highest index in Trap 1 was 0.88 in October, in Trap 2, 0.82 in July and in Trap 3, 0.63 in July. The diversity above 1,000 meters was most various in July. The five dominant species of C. pinguis, C. lata, H. dentipes, F. scalaris, and L. caesar showed distinctive seasonal prevalence, relative abundance and altitudinal distribution respectively.