Crustacean Research 2020 Vol.49: 15–21 ©Carcinological Society of Japan. doi: 10.18353/crustacea.49.0_15 Areolate , areolatus (: ), a new host record for Lernaeenicus ramosus (Copepoda: Pennellidae), with comments on the known hosts and distribution records of the copepod in the Indo-West Pacific region

Kazuya Nagasawa, Kenyu Suzuki, Fumihito Muto

Abstract.̶ An ovigerous female of Lernaeenicus ramosus Kirtisinghe, 1956 was collected from an areolate grouper, Epinephelus areolatus (Forsskål, 1775), in coastal waters of Suruga Bay (western North Pacific Ocean), Shizuoka Prefecture, central Ja- pan. This represents a new host and the easternmost distribution records for L. ramo- sus. Based on the literature published between 1956 and 2019, this paper tabulates the known hosts and distribution records of the species in the Indo-West Pacific region. The recent collections of L. ramosus from Japan further support a previous suggestion that the geographical distribution of the species in Japanese waters is affected by two warm currents, the Kuroshio, and its branch, the Tsushima Current.

Key words: fish parasite, geographical distribution, host range, pennellid, Serranidae

The pennellid copepod Lernaeenicus ramo- ramosus from an areolate grouper, Epinephelus sus Kirtisinghe, 1956 is a mesoparasite of per- areolatus (Forsskål, 1775), in Suruga Bay ciform fishes in the Indo-West Pacific region (western North Pacific Ocean), Shizuoka Pre- (Nagasawa & Uyeno, 2014). The species was fecture, central Japan. This represents a new originally described using females from comet host and the easternmost distribution records grouper, Epinephelus morrhua (Valenciennes, for L. ramosus. The species has been well re- 1833), in the Indian Ocean off Ceylon (now Sri described by Shiino (1958) and Izawa (2019) Lanka) (Kirtisinghe, 1956) and since has been using specimens from Japan. Thus, this paper reported from in India (Pillai, 1985) briefly reports on the morphology of L. ramo- and Japan (see below) and from bluestriped sus from the bay and, based on the literature fangblenny, Plagiotremus rhinorhynchos published between 1956 and 2019, gives a list (Bleeker, 1852) (as Runula rhinorhynchus) in of the known hosts and collection localities of Australia (Boxshall, 1986). the species. Much information has been accumulated on An areolate grouper was caught using rod various aspects of the biology, such as taxono- and line in coastal waters of Suruga Bay off my, geographical distribution, host range, lar- Miho, Shimizu (35°02′02.1″N,138°52′45.5″E), val development, and pathogenicity, of L. ra- Shizuoka Prefecture, on 19 September 2019. mosus in Japan, where the groupers are known The fish was transported alive to the laboratory to serve as hosts of the species (Shiino, 1958, of the School of Marine Science and Technolo- 1964; Anonymous, 2004; Doi, 2007; Doi et al., gy, Tokai University, Shimizu, where it was 2008; Nagasawa et al., 2010, 2011, 2014; Oka- measured for standard length (SL, mm) and ex- moto, 2011; Nitta et al., 2017; Izawa, 2019). amined for ecto- and endoparasites. One cope- Recently, we collected an adult female of L. pod was found, removed carefully, and fixed in

Received: 20 Oct 2019. Accepted: 25 Dec 2019. Published online: 13 Feb 2020. 15 KAZUYA NAGASAWA ET AL.

70% ethanol. Later, at the Aquaparasitology well developed, nearly elongated, and ends Laboratory, Shimizu, the copepod was exam- bluntly without caudal rami (Fig. 2A). ined for its morphology and identified as L. ra- Lernaeenicus ramosus was described from mosus. A drawing was made with the aid of a Sri Lanka (Kirtisinghe, 1956). Later, the spe- drawing tube fitted on an Olympus SZX10 ste- cies was redescribed by Shiino (1958) and, reo microscope. The specimen preserved in again, by Izawa (2019) based on the material 70% ethanol is deposited in the Crustacea (Cr) from Japan. Pillai (1985) and Boxshall (1986) collection of the National Museum of Nature also described the species using specimens and Science, Tsukuba, Ibaraki Prefecture from Indian and Australia, respectively. All (NSMT-Cr 26743). The scientific and common these authors examined metamorphosed fe- names of fishes mentioned in this paper follow males. Izawa (2019) stated that the females Froese & Pauly (2019). from Sri Lanka, Japan, and Australia are mor- An ovigerous female of L. ramosus inserted phologically identical to each other. No mor- the anterior part of its body into the host phological difference is observed between the (132 mm SL) near the base of the dorsal fin. specimen examined in this study and those re- This anterior part was embedded in the host ported by Shiino (1958) and Izawa (2019). musculature. The posterior part of the female However, it is desirable to identify the species, protruded externally and was deep purple in using molecular data as well, from these three color when fresh (arrowhead in Fig. 1). countries and India, because Japan and Austra- Description of female: The anterior part of lia are far separated from Sri Lanka and India the body consists of the head, 2.0 mm long, and it parasitizes groupers in Sri Lanka, India, with three pairs of branching holdfasts and a and Japan but does not in Australia. Nitta et al. slender, cylindrical neck, 2.6 mm long (Fig. 2). (2017) successfully obtained molecular data of The anterior and the middle pairs arise, respec- L. ramosus from Hong Kong grouper, Epi- tively, from the dorsolateral and the ventrolat- nephelus akaara (Temminck & Schlegel, eral corners in the anterior portion of the head, 1842), in Japan. while the posterior pair does from the lateral Excluding the blenniid fish from Australia surface in the posterior portion of the head (Boxshall, 1986), the other known hosts are all (Fig. 2B, C). Each holdfast is swollen near its groupers (Serranidae). The areolate grouper is base and possesses slender branches. The pos- added herein as a new host of L. ramosus, and terior part of the body comprises the trunk and a total of eight species of groupers is now the abdomen: the former is longer (7.0 mm known as its hosts (Table 1, seven species from long) than the latter (4.8 mm long), which is Japan; one species from Sri Lanka and India). It is evident that L. ramosus almost exclusively uses groupers as its hosts, and Nagasawa et al. (2014) have suggested that the species will be discovered from other species of groupers in Japan, where they (subfamily Epinephelinae) consist of 65 species in 10 genera (42 spp. in Epinephelus, 12 spp. in , 3 spp. in , 2 spp. in , 1 sp. each Fig. 1. Areolate grouper, Epinephelus areolatus, infected by in Aethaloperca, Anyperodon, Chromileptes, Lernaeenicus ramosus (arrowhead) near the base of the dorsal Gracila, Saloptia, and Triso) (Senou, 2013). fin, fresh specimen. The fish was caught in coastal waters of Suruga Bay off Miho, Shizuoka Prefecture, central Japan, on We need to explain that E. morrhua is listed 19 September 2019. Scale bar: 10 mm. in Table 1 as the host of L. ramosus from India.

16 Crustacean Research 49 NEW HOST RECORD FOR A PARASITIC COPEPOD

Fig. 2. Lernaeenicus ramosus, ovigerous female, NSMT-Cr 26743, from Epinephelus areolatus, caught in coastal waters of Suruga Bay off Miho, Shizuoka Prefecture, Japan. A, habitus, ventrolateral view; B, head and neck, ventrolateral view; C, head and anterior part of neck, dorsolateral view. The photographs were taken immediately after the specimen was fixed in 70% ethanol. Abbreviations: ap, anterior pair of holdfast; h, head; mp, middle pair of holdfast; n, neck; pp, posterior pair of holdfast. Scale bars: A, 4 mm; B–C, 2 mm.

In his monograph of the parasitic copepods of and India (Pillai, 1985) should have been list- India, Pillai (1985: 721) reported three species ed. Moreover, Raja et al. (2016: table 3) in- of groupers (E. morrhua, E. akaara, E. tsirime- cluded the Japanese threadfin bream, “Nemip- naria) as the hosts of L. ramosus from Sri Lan- terus japonicus (Block, 1791)” (Nemipteridae) ka, India, and Japan but did not specify the In- among Indian hosts of L. ramosus. This fish dian host. However, the latter two species are species (as “red snapper, Synagris japonica the Japanese hosts (Shiino, 1958), thus the re- Day”) was reported by Rangnekar (1961) to maining species, E. morrhua, can be regarded harbor “L. ramosus” off Bombay (now Mum- as the Indian host, as earlier reported from Sri bai), but the copepod collected was not L. ra- Lanka (Kirtisinghe, 1956). mosus but Lernaeenicus nemipteri Gnana- Raja et al. (2016: table 3) listed the red grou- muthu, 1953 (see Pillai, 1985: 721–722). The per “Epinephelus morio (Valenciennes in Cuvi- Japanese threadfin bream is apparently not the er & Valenciennes, 1826)” as one of the hosts host of L. ramosus. of L. ramosus but it is wrong: E. morio is a Lernaeenicus ramosus has been reported species found only in the western Atlantic from off Sri Lanka, India, Australia, and Japan Ocean (Froese & Pauly, 2019) and E. morrhua (Table 1). While no detailed information on the reported from Sri Lanka (Kirtisinghe, 1956) collection locality of the species in India is

Crustacean Research 49 17 KAZUYA NAGASAWA ET AL.

) (2008) ) Reference (2011, 2014) (2011, (2011) (2014) * (2017) et al. E. septemfasciatus [sic]) Okamoto (2011) Okamoto (2011) Shiino (1958, as E. tsirimenaria [sic]) Shiino (1964, as E. fasciatus Anonymous (2004), Okamoto (2011) Nagasawa et al. Anonymous (2004), Okamoto (2011, as Boxshall (1986, as Runula rhinorhynchus Anonymous (2004), Nagasawa et al. (2010), Shiino (1958, as E. tsirimenaria [sic]) This paper Nagasawa et al. Anonymous (2004), Nagasawa et al. (2010), Nagasawa et al. (2014) Nagasawa et al. Izawa (2019) Kirtisinghe (1956) Pillai (1985) Shiino (1958, as E. tsirimenaria [sic]) Doi (2007), et al. Nitta

11 4 7 12 12 1 9 12 5 3 10 12 2 6 8 Number in Fig. 2 Locality Collection locality Kagoshima Shimane Yamaguti Shimane Shimane Shimane Oshima Strait, Amami-oshima Island, waters, coastal adjacent and Hamada Nishiyama and Murotsu, Shimonoseki, waters, coastal adjacent and Hamada Great Barrier Reef, Queensland Seto, Wakayama Not reported Miho, Shimizu, Shizuoka Shinkamigoto, Nagasaki waters, coastal adjacent and Hamada Furumugi, Tokushima Kowa-ura, Mie Tsushima, Nagasaki Tsushima, waters, coastal adjacent and Hamada Wadge Bank (type locality) Wadge Not reported Momotori, Mie Kobe, Hyogo Amakusa-nada Sea, Kumamoto Country is listed herein as the Indian host because E. tsirimenaria ) as hosts of L. ramosus , but only morrhua Japan Australia Japan Japan Japan Japan Japan Sri Lanka India Japan E. akaara , . The scientifc and common names of the fishes listed follow Froese & Pauly (2019). Lernaeenicus ramosus . in Senou (2013). Common name Convict grouper Bluestriped fangblenny Blacktip grouper Areolate grouper grouper Yellow Longtooth grouper Comet grouper Comet grouper Hong Kong grouper (type host) (type Host Epinephelus septemfasciatus Genus and species septemfasciatus ** rhinorhynchos Plagiotremus Epinephelus fasciatus Epinephelus areolatus Epinephelus awoara Epinephelus bruneus Epinephelus chlorostigma Epinephelus morrhua Epinephelus Epinephelus morrhua Epinephelus akaara Table Table 1. Known hosts and collection localities of Family This species is listed as two other grouper species were based on the record from Japan (Shiino, 1958). Blenniidae , Pillai (1985: 721) listed three species of groupers ( E. morrhua Serranidae * **

18 Crustacean Research 49 NEW HOST RECORD FOR A PARASITIC COPEPOD available (Pillai, 1985), those in India, Sri Lan- ka (Wadge Bank, Kirtisinghe, 1956), and Aus- tralia (Great Barrier Reef, Boxshall, 1986) are found in tropical waters. As indicated below, in Japan, the species occurs in subtropical to tem- perate waters. These indicate that L. ramosus has a wide distribution range from tropical through subtropical to temperate waters in the Indo-West Pacific region. The Japanese tem- perate waters are located at the northern limit of distribution of L. ramosus. Based on the published information on col- lection localities of L. ramosus in Japan (Table 1), the species occurs in the western North Pa- cific (localities 1–5 and 7 in Fig. 3), the Seto Inland Sea (locality 6), the East China Sea (lo- calities 8–10), and the Sea of Japan (localities Fig. 3. Map of the Japanese Archipelago, showing the 11–12). The specimen of L. ramosus reported localities (1–12) where Lernaeenicus ramosus was collected in the previous (closed circles) and present (open circle) studies herein extends its distribution range from Mo- (updated from Nagasawa et al., 2011). 1, Suruga Bay off Miho, motori, Mie Prefecture (locality 2) eastward to Shizuoka (this paper); 2, Momotori, Mie (Shiino, 1958); 3, Suruga Bay, Shizuoka Prefecture (locality 1) Kowa-ura, Mie (Nagasawa et al., 2014); 4, Seto, Wakayama off the Pacific coast of Japan. As indicated by (Shiino, 1958); 5, Furumugi, Tokushima (Nagasawa et al., 2014); 6, Kobe, Hyogo (Doi, 2007; Doi et al., 2008); 7, Nagasawa et al. (2010, 2011), the geographical Oshima Strait, Amami-oshima Island, Kagoshima (Shiino, distribution of L. ramosus in Japanese waters is 1964, reported as Ooshima Strait, Amamiooshima); 8, affected by two warm currents, the Kuroshio, Amakusa-nada Sea, Kumamoto (Nitta et al., 2017); 9, and its branch, the Tsushima Current (Fig. 3). Shinkamigoto, Nagasaki (Nagasawa et al., 2011); 10, Tsushima, Nagasaki (Izawa, 2019); 11, Nishiyama and The species has been reported from the sub- Murotsu, Shimonoseki, Yamaguchi (Nagasawa et al., 2011, tropical (locality 7) and temperate (other locali- 2014); 12, Hamada and adjacent coastal waters, Shimane ties) waters. (Anonymous, 2004; Nagasawa et al., 2010; Okamoto, 2011). In the Japanese temperate waters, adult fe- The routes of the Kuroshio and its branch, the Tsushima Current, are also shown. males of L. ramosus have been most frequently found on groupers during the late summer to early winter (September to November, see Nit- still maintained a high level of infection in the ta et al., 2017). The specimen reported in this grouper populations and has been expanding paper was also the ovigerous female collected its distribution range. in September. Seawater temperatures fluctuate seasonally in the Japanese temperate waters, ■ Acknowledgements and the maturation of L. ramosus may be ac- celerated by high seawater temperatures during We thank Yuji Tanaka and Qian Zhang, To- the summer. kyo University of Marine Science and Technol- The outbreaks of L. ramosus occurred in the ogy, Tokyo, and Balu Alagar Venmathi Maran, 2000’s among grouper populations in Japanese Borneo Marine Research Institute, University waters (Nagasawa et al., 2011). The recent col- Malaysia Sabah, Kota Kinabalu, for their assis- lections of the species (Nitta et al., 2017; Iza- tance with the relevant literature. We are also wa, 2019; this paper) may indicate that it has grateful to an anonymous reviewer for useful

Crustacean Research 49 19 KAZUYA NAGASAWA ET AL. comments to improve the manuscript. (Copepoda, Pennellidae) in the Sea of Japan. Biogeography, 12: 13–15. ■ Literature Cited Nagasawa, K., Doi, H., & Yokoyama, F., 2011. Further records of Lernaeenicus ramosus Anonymous, 2004. [Ectoparasites of groupers]. (Copepoda: Pennellidae) from groupers Tobiuo Tsushin, Gogai Tobikkusu, 1: 1–2. (Epinephelus spp.) in Japanese waters. Bio- (in Japanese). geography, 13: 51–53. Boxshall, G. A., 1986. A new genus and two new Nagasawa, K., Yuasa, A., Doi, H., & Isozaki, S., species of Pennellidae (Copepoda: Siphono- 2014. Lernaeenicus ramosus (Copepoda: stomatoida) and an analysis of evolution Pennellidae), a parasite of groupers from off within the family. Systematic Parasitology, Japan, with two new host records. Biogeog- 8: 215–225. raphy, 16: 53–56. Doi, T., 2007. Record of Lernaeenicus ramosus Nitta, M., Hotta, T., & Nagasawa, K., 2017. New (Copepoda, Pennellidae) parasitic on a red- record of Lernaeenicus ramosus (Copepoda: spotted grouper, Epinephelus akaara col- Pennellidae) parasitic on Epinephelus lected from a fishing port in Kobe City. akaara (Perciformes: Serranidae) from the Nankiseibutu, 49: 108–110. (in Japanese Amakusa-nada Sea, western Japan. Bioge- with English abstract). ography, 19: 80–84. Doi, T., Noda, A., & Hama, N., 2008. Histologi- Okamoto, M., 2011. The parasites of fishes and cal observation of red-spotted grouper Epi- shellfishes caught in the south-western Sea nephelus akaara parasitized by Lernaeeni- of Japan off Shimane Prefecture. Report of cus ramosus (Copepoda, Pennellidae) and a Shimane Prefectural Fisheries Technology case of spontaneous recovery. Aquaculture Center, 3: 55–68. (in Japanese with English Science, 56: 601–602. (in Japanese with abstract). English abstract). Pillai, N. K., 1985. The Fauna of India. Copepod Froese, R., & Pauly, D., (eds.), 2019. FishBase. Parasites of Marine Fishes. Zoological Soci- World Wide Web electronic publication. ety of India, Calcutta, 900 pp. www.fishbase.org (04/2019) (accessed 10 Raja, K., Saravanakumar, A., Gopalakrishnan, A., October 2019). Vijayakumar, R., Hwang, U. W., & Ven- Izawa, K., 2019. Redescription of Lernaeenicus mathi Maran, B. A., 2016. The genus Ler- ramosus Kirtisinghe, 1956 (Copepoda, Si- naeenicus Lesueur (Copepoda, Siphonosto- phonostomatoida, Pennellidae), with de- matoida, Pennellidae) in India: a checklist scription of its male and the postnaupliar de- with notes on its and ecology. velopmental stages. Crustaceana, 92: Zootaxa, 4174: 192–211. 119–128. Rangnekar, M. P., 1961. Copepods parasitic on Kirtisinghe, P., 1956. Parasitic copepods of fish fishes of Bombay. I. Lernaeopodoida. Jour- from Ceylon. IV. Parasitology, 46: 14–21. nal of the University of Bombay (Natural Nagasawa, K. & Uyeno, D., 2014. A checklist of Science), Series B, 29: 195–205. copepods of the family Pennellidae (Sipho- Senou, H., 2013. Serranidae: groupers, basslets nostomatoida) from fishes and whales in and soapfishes. In: T. Nakabo, (ed.), Fishes Japanese waters (1916–2014). Biosphere of Japan with Pictorial Keys to the Species. Science, 53: 43–71. (in Japanese with Eng- Third Edition. Tokai University Press, Hada- lish abstract). no, pp. 757–802 and 1960–1971. (in Japa- Nagasawa, K., Mukai, T., Sota, K., & Yamauchi, nese with English title). T., 2010. Heavy infection of groupers Epi- Shiino, S. M., 1958. Copepods parasitic on Japa- nephelus spp. with Lernaeenicus ramosus nese fishes. 17. Lernaeidae. Report of Facul-

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Addresses (KN) Graduate School of Integrated Sciences (KS) (FM) School of Marine Science and for Life, Hiroshima University, 1–4–4 Technology, Tokai University, 3–20–1 Orido, Kagamiyama, Higashi-Hiroshima, Hiroshima Shimizu, Shizuoka 424–8610, Japan 739–8528, Japan (KN) Present address: Aquaparasitology Laboratory, 365–61 Kusanagi, Shimizu, E-mail address of corresponding author Shizuoka 424–0886, Japan (KN) [email protected]

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