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.
Highlights
The harpacticoid copepod, Laophontidae Scott T., 1904 is one of the largest families consisting of more than 320 valid species in 75 genera (Ahyong et al, 2011; Huys & Lee, 2018)
Paratypes: Paratype 1, 1♀ dissected on four slides (NIBRIV0000865934); Paratype 2, 1♀ dissected on seven slides (NIBRIV0000865935); Paratype 3, 1♀ dissected on 10 slides (NIBRIV0000865936); Paratype 4, 1♀ dissected on nine slides (NIBRIV0000865937); Paratype 5, 1♂ dissected on eight slides (NIBRIV0000865938); Paratype 6, 1♂dissected on six slides (NIBRIV0000865939); Paratypes 7–12, 6♂ ♂ on each slide (NIBRIV0000865940–0000865945); Paratype 13, 2♂ ♂, in toto, on a scanning electron microscope (SEM) stub (NIBRIV0000865946); Paratypes 14–16, 1♀2♂ ♂ on each SEM stubs (NIBRIV0000865947–0000865949)
Q. enormis can be distinguished from Q. longifurcata by the following differences: (1) Q. longifurcata, but not Q. enormis, has an outer seta on the P4 enp-2 in both sexes (Table 1); (2) on the female P4 exp-2, an inner seta is present in the Q. longifurcata and lacking in the new species (Tables 1–2); (3) the new species has two setae on the syncoxa of the maxilliped, but Q. longifurcata has only one seta (Table 3)
Summary
The harpacticoid copepod, Laophontidae Scott T., 1904 is one of the largest families consisting of more than 320 valid species in 75 genera (Ahyong et al, 2011; Huys & Lee, 2018). The available sequences are few, Yeom et al (2018) analyzed the phylogenetic relationships among five laophontid genera (Laophontina Norman & Scott T., 1905; Microchelonia Brady, 1918; Paralaophonte Lang, 1948; Pseudonychocamptus Lang, 1944; Vostoklaophonte Yeom et al, 2018 using partial sequences of 18S ribosomal RNA (rRNA) gene and revealed a close relationship between Vostoklaophonte and Microchelonia. Wells (2007) noted that this family has variable setation on the second to fourth swimming legs. The genus Quinquelaophonte Wells, Hicks & Coull, 1982 was raised to accommodate species incorporated in the quinquespinosa-group of Heterolaophonte Lang, 1948 with the The variation can appear within a population or between populations, between the sexes and, even, between the left and right rami of a pair of legs in a single individual.
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