Full length articleThree synonyms of the coastal Phucobius sharp species (Coleoptera: Staphylinidae) are proposed based on morphological and molecular characters
Graphical abstract
Introduction
The marine littoral staphylinine genus Phucobius Sharp was established based on Phucobius simulator Sharp (1874) from Japan and contains eight species occurring along the coasts of the Western Pacific and Indian Oceans (Frank and Ahn, 2011). They are known to be predators in decaying seaweeds on beaches.
During an ongoing study toward a world revision of the Cafius Stephens complex, we found that some Phucobius species from the western Pacific Ocean including the South China Sea are superficially similar to each other in external structure and male genital structure. These findings motivated us to study species delimitation of these Phucobius species using an integrative approach (Dayrat, 2005, Song and Ahn, 2014, Will et al., 2005, Yeates et al., 2011), with multiple lines of evidence for consistent species identification.
We studied about 150 Phucobius specimens, collected from the broad geographic regions (see below) and they are compared with the type specimens. In addition, we used molecular characters (genetic divergence data and gene tree monophyly) for species delimitation based on two loci (COI and 28S) in order to test the accuracy of the morphologically assigned four Phucobius species.
In this paper, three new synonyms are proposed for Phucobius pectoralis (Boheman, 1858): P. simulator Sharp, 1874, syn. nov., P. tricolor Bernhauer, 1917, syn. nov., and P. densipennis Bernhauer, 1931, syn. nov. Phucobius pectoralis is redescribed with illustrations of diagnostic characters. Also, the intraspecific variation among the populations of P. pectoralis is briefly discussed.
Section snippets
Materials and methods
For the study of morphological characters, we selected numerous specimens with different geographic distribution for the study of intraspecific variation, and dissected and cleared the whole body for examining microstructures. Habitus and scanning electron microscope (SEM) photographs followed the methods described by Yoo and Ahn, 2020, Lee and Ahn 2016, respectively.
Depository of specimens examined is as follows: The Natural History Museum, London, United Kingdom (BMNH); Bernice Pauahi Bishop
Molecular character analysis
In total, 53 new sequences from the Russian Far East thorough Korea and Japan to Vietnam [26 individuals of 3 Phucobius species and 2 individuals of Cafius vestitus (Sharp)] were generated (856 bp of partial COI gene region and 1004 bp of partial 28S). All new sequences were deposited in GenBank (accession numbers: MT937197–MT937224 and MT937255–MT937279 in Table 1).
Genetic divergence of COI using uncorrected p-distance among three Phucobius species ranged from 0.23% (between P. simulator from
Discussion
Eight Phucobius species have been recorded in the world (Frank and Ahn, 2011) and their diagnostic characters include body color and shape and structure of male genitalia. However, three of these had been suspected in their identifications. Bernhauer (1932) first pointed out that the type of P. pectoralis (Boheman) is similar to P. simulator. Later, Naomi (1984) also noted that three species (Phucobius simulator, P. densipennis Bernhauer, and P. tricolor Bernhauer) resembled each other in
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank A. F. Newton and M. K. Thayer (FMNH), R. Booth (BMNH), J. Hájek and M. Fikáček (NMPC), J. Bergsten (NHRS), S. Blank (SDEI) S. Myers (BPBM), A. Davies (CNC), and Z.-H. Zhou (IZ-CAS) for providing us with many specimens including type series, and H. Hoshina (Fukui University, Japan), N. Kobayashi (Saitama Prefectural University, Japan), H. Kojima (Tokyo University of Agriculture, Japan), and T. Ban (Natural History Museum and Institute, Chiba, Japan) for the productive collecting trips
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2022, Journal of Asia-Pacific EntomologyCitation Excerpt :We selected many specimens with different geographic distributions for their intraspecific variation to study morphological characters, and dissected and cleared the whole body for examining microstructures (see Specimens Examined below). Scanning electron microscope (SEM) and habitus photographs followed the methods described by Yoo et al. (2021a). Depository of specimens examined is as follows: Australian National Insect Collection (ANIC), Canberra, Australia; The Natural History Museum (BMNH), London, United Kingdom; Bernice Pauahi Bishop Museum (BPBM), Honolulu, USA; Canadian National Collection of Insects (CNC), Ottawa, Canada; Chungnam National University Insect Collection (CNUIC), Daejeon, Korea; and Field Museum of Natural History (FMNH), Chicago, USA; Museum of Zoology, Lund University (MZLU), Lund, Sweden; Muséum national d'Histoire naturelle (MNHN), Paris, France; Naturhistorisches Museum (NMW), Vienna, Austria.
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