Quinquelaophonte enormissp. nov., a new interstitial copepod (Harpacticoida: Laophontidae) from Korea

Abstract

We collected an undescribed laophontid copepod from a coarse sand habitat on the east coast of Korea and named it Quinquelaophonte enormis sp. nov. We compared the detailed morphological characteristics of the new species with those of congeneric species. Among them, the new species shows a superficial resemblance to the Californian species Quinquelaophonte longifurcata Lang, 1965. However, the two species are easily distinguishable by the setation of the syncoxa on the maxilliped and the fourth swimming leg. The new species has the variable setation on the second to fourth swimming legs. The variations appear among individuals or between the left and right rami of a pair of legs in a single specimen. Although complex chaetotaxical polymorphism occur in this new species, we used myCOI and Cytb to confirm that the new species is not a species complex. Also, partial sequences of 18S and 28S ribosomal RNA genes were used to analyze the position of the new species within the family Laophontidae. The new speciesis the fourteenth Quinquelaophonte species in the world and the second species in Korea.

An Integrative Approach for Identifying Quinquelaophonte (Harpacticoida, Laophontidae) Species from Korea with the Description of a New Species

“…However, due to the limited available information, it is premature to suggest a phylogeographic history and evolutionary relationships among the examined species. However, we noticed that Q. enormis is geographically closer to the new species (Republic of Korea [17]) than Q. aurantius, which was reported from the opposite hemisphere (New Zealand [9]). In Korean fauna, in addition to these two species, there is one more species, Q. koreana, which is intuitively distinguishable (e.g., short caudal rami, two setae on the exopod of the antenna, two inner setae on the P3 exp-3 in both sexes, four armatures on the distal endopal segment of the P4 in both sexes, and the shape of the female P5) and was reported from the coast of the Yellow sea [16].…”

“…We confirmed that these Quinquelaophonte individuals were conspecific and distinct from congeners using an integrative approach, including morphological and genetic data. The discovery of the new species is the third in the Northwest Pacific, following Q. koreana (Taean, Republic of Korea [16]) and Q. enormis (Busan, Republic of Korea [17]). Moreover, we inferred the phylogenetic relationships among the new species and two congeners (Q. aurantius and Q. enormis).…”

“…nov. is most similar to species that are characterized by long caudal rami (length/breadth ≥ 3), the number of setae on the exopod of the antenna (three setae), a minute accessory seta on the P1 enp-2, and the number of armature elements on the P3 exp-3 (less than seven). These morphological characteristics of the new species are shared with Q. aestuarii [15], Q. aurantius [9], Q. capillata [10][11][12]24], Q. enormis [17], Q. longifurcata [43], Q. parasigmoides [6,7], and Q. varians [14].…”

“…The variability appears between populations, within a population, and between left and right rami. Quinquelaophonte species inhabit various substrata, e.g., silty sand, intertidal mud, and gravel, and are widely distributed around the world, e.g., the Central Indo-Pacific [5], Western Indo-Pacific [6,7], Temperate Australasia [1,8,9], Temperate Northern Atlantic [10][11][12], Tropical Atlantic [13], Temperate South America [14,15], and Temperate Northern Pacific [16,17] realms. All Quinquelaohponte species were reported from Diversity 2023, 15, 1168 2 of 21 only the type locality or relatively close localities, with two exceptions, Q. quinquespinosa (Sewell, 1924) and Q. capillata (Wilson, 1932).…”

New genus of the family Laophontidae T. Scott, 1905 (Copepoda, Harpacticoida) from Hupo on the eastern coast of Korea

“…The family Laophontidae T. Scott, 1905 is essentially marine, free-living and benthic, mainly inhabiting the intertidal zone or shallow subtidal habitats and is commonly found amongst algae and seagrass ( Huys et al 1996 , Boxshall and Halsey 2004 , Kaymak and Karaytuğ 2014 ). Additionally, the Laophontidae is a very large and diverse family containing more than 320 species and 74 genera in the Harpacticoida ( Huys and Lee 2018 , Kim et al 2020 ).…”