Cirrhimuraena chinensis Kaup, 1856

Cirrhimuraena chinensis Kaup, 1856 View in CoL

[New standard Japanese name: Gotenba-umihebi] ( Figs 1–5 View Fig View Fig View Fig View Fig View Fig ; Table 1)

Material. KMNH VR 100620, 240mm + (tip of tail slightly damaged), Gotenba-kaigan coast ( western Ise Bay ), Tsu, Mie Prefecture, Japan, 11 February 2024, coll . E . Agyeman. Description. Counts and measurements are shown

© 2025 The Japanese Society of Systematic Zoology.

This is an open access article distributed under a Creative Commons Attribution 4.0 License ( CC BY, https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and in Table 1. Body slender, cylindrical, posterior tail weakly compressed ( Fig. 1 View Fig ); depth of trunk not reduced, tail tapering towards posteriorly; tail tip slightly broken but longer than preanal length, 1.5 in TL, 0.4 in trunk. Head moderate in size, 10.0 in TL, 2.5 in trunk and 3.5 in preanal lengths; dorsal contour smooth anteriorly, weakly convex on occipital; snout long, acute, length about 3 times of eye diameter; dorsally on snout with extremely shallow dimple; ventrally on snout with a distinct short groove, beyond anterior edge of base of anterior-nostril tube ( Fig. 2b View Fig ); eye small, center of eye slightly behind half way of maxilla; eye covered by transparent skin; anterior nostril tubular, short, shorter than eye diameter; posterior nostril along inside upper lip, concealed by a broad dermal flap; mouth large, rictus well behind posterior margin of eye; edge of lips smooth, cirri present along upper lip, 15 left side and 17 right side; tips of cirri pointed, cirri located just behind posterior margin of eye and third one counted from end of the row longer than others ( Figs 2a, b View Fig , 3 View Fig , 4 View Fig ); interorbital region weakly convex; branchial basket swollen; gill opening located ventrolaterally of breast, membrane of opening formed c-shaped.

Sensory pores on head small but obvious, supraorbital pores 1 (ethmoid) + 3, infraorbital pores 3 + 3, preoperculomandibular pores 6 + 3 (left side partly damaged, only 4 pores on mandible), and supratemporal pores 3 ( Fig. 3 View Fig ); interorbital pore present; lateral-line pores developed, ending before one snout length from tip of tail.

All teeth small and slender; teeth on maxilla two rows anteriorly, increased to five rows towards posteriorly, inner teeth long and recurved ( Fig. 4 View Fig ); vomerine teeth one row anteriorly and two rows posteriorly; dentary teeth two rows; 7 intermaxillary teeth arranged chevron-shape, concealed by dermal structure in part.

Dorsal fin originating above mid pectoral fin, height not elevated mostly, weakly reduced in posterior 1/5 of tail; height of anal fin clearly higher than dorsal fin, elevated in posterior part of tail, but reduced in same longitudinal part of dorsal fin; pectoral fin well developed and recurved, its tip filamented ( Figs 1b View Fig , 5a, b View Fig ).

When alive condition ( Fig. 5a, b View Fig ), body yellowish light brown with numerous melanophores except abdomen; abdomen generally greyish white, anterior border yellowish, and around stomach blueish; head yellowish light brown dorsally, pale brown to white from lower jaw to branchial basket; iris silver; all fins semitransparent white. After preservation body changing to faded brown, eyes broadly covered by whitish skin.

Note of collecting environments. The specimen in this report was collected from an intertidal flat formed by a sandy muddy bottom. Shellfish such as clams and mussels [including Cyclina sinensis (Gmelin, 1791) , Mactra chinensis Philippi, 1846 , Meretrix lusoria (Röding, 1798) , Neverita didyma (Röding, 1798) , Venerupis philippinarum (Adams and Reeve, 1850) ] were also found in the sampling site. The specimen appeared when the sandy mud was shoveled by a grass sickle with a 15 cm blade, landward side of shoreline at low tide around midnight. The specimen may have burrowed into the sandy mud shallower than the blade length.

Distribution. At least China (north to mouth of Yangtze River), Taiwan, and Japan ( Zhuang et al. 2006; Li et al. 2014; Ho et al. 2015; this study) (see Remarks).

Remarks. The genus Cirrhimuraena Kaup, 1856 is characterized by having a tail longer than the pre-anal length, the origin of the dorsal fin positioned above the head or near the gill opening, small or well-developed pectoral fins, numerous cirri on the upper lip but none on the lower jaw, and small and slender teeth ( McCosker 2022). While up to 12 valid species of Cirrhimuraena have been recognized, some researchers suggest around 7 species in minimum ( Mohapatra et al. 2021; McCosker 2022; Fricke et al. 2024), indicating that the species-level taxonomy of this genus is not well revised. However, when examining the characteristics of the recognized nominal species, they can be broadly divided into two groups: one with a head length less than 9% TL, pre-anal length less than 28% TL, and pectoral-fin length less than 34% of the head length; and the other with a head length greater than 10% TL, pre-anal length greater than 29% TL, and pectoral-fin length greater than 50% of the head length ( Bleeker 1860a, b, 1863; Mohapatra et al. 2021; this study). Although the tip of the present specimen’s tail is slightly damaged, the lost portion is estimated to be less than 5 mm based on the tail shape when compared with non-damaged specimens. Therefore, the head length of this specimen is estimated to be a minimum of 9.7% TL and the preanal length is that of 33.7% TL. In addition, it has a long pectoral fin greater than 50% of the head length ( Table 1). Consequently, the present specimen matches the characteristics of the latter group.

Each species of Cirrhimuraena is highly similar to the others, but the position of the dorsal-fin origin, the ratio of head length to total length and pre-anal length, the ratio of upper jaw and pectoral-fin lengths to head length, the number of rows of upper jaw teeth and vomerine teeth, and the vertebral count are considered as available characters for species classification ( Mohapatra et al. 2021). After examining all the original descriptions of each nominal species of Cirrhimuraena and some type specimens (see Comparative materials), the present specimen can be identified as Cirrhimuraena chinensis based on the following combination of morphological characters: the origin of the dorsal fin is positioned posterior to a vertical through the gill opening; the vomerine teeth are arranged in a single row anteriorly; the pectoral fins are elongated and tip pointed, length more than 50% of the head length; and the vertebral formula is 11-46-152+ (the posterior part of the tail slightly damaged, estimated to be missing 2 to 4 vertebral elements) ( Kaup 1856; this study) ( Table 1). The morphology of the specimen also closely matched that of the Taiwanese specimens used for comparison. Five specimens of various lengths (preanal length 80.8 to 102.8 mm) from Matsu Island along the southeastern coast of mainland China were observed, revealing that the number of rows of vomerine teeth remained unchanged anteriorly but increased from two rows to three rows posteriorly with growth. In the smallest specimen, the number of rows of upper jaw teeth is two in the anterior region and four in the posterior region, while in the largest specimen, it is three in the anterior region and six in the posterior region. Therefore, there appears to be some growth variation in these tooth row counts, and it is necessary to reconsider their availability for species classification.

The nominal species included in the group with large head size and large pectoral fins are C. chinensis , C. indica Mohapatra, Mohanty, Ray, Mishra, and Seth, 2021 , C. paucidens Herre and Myers, 1931 , C. taeniopterus Bleeker, 1863 , Jenkinsiella inhacae Smith, 1962 , J. nectura Jordan in Jordan and Seale, 1907, and Ophisurus polyodon Bleeker, 1860 . Cirrhimuraena indica and C. inhacae differ from C. chinensis in having higher total vertebral counts (164–167 in C. indica ; 164–169 in C. inhacae vs. 151–154 in C. chinensis ) and the position of the origin of the dorsal fin (behind gill opening vs. slightly anterior or above the gill opening) ( Mohapatra et al. 2021; McCosker 2022; this study). The vertebral count of one syntype of C. taenioptera (vertebral formula 10/46/159) [Mohapatra et al.’s (2021) count is incorrect] is similar to that of C. chinensis (151– 154). However, it is evident that the origin of the dorsal fin of the remain syntype of C. taenioptera is positioned anterior to the vertical through the gill opening based on YH’s observation, distinguishing it from C. chinensis .

There is an opinion suggesting that J . nectura may be a junior synonym of C. taenioptera , and C. paucidens may be a junior synonym of C. chinensis ( McCosker 1977) . Jenkinsiella nectura , whose taxonomic status is uncertain, shares the characteristic of the origin of the dorsal fin behind the vertical through the gill opening with C. chinensis , but has a higher vertebral count 164 (this study). Cirrhimuraena paucidens is a species described based on one specimen purchased from Hainan Island , southern China, and it appears morphological features such as the position of the origin of the dorsal fin, the number of rows of vomerine teeth, and the vertebral count that matched those of C . chinensis mentioned above. Therefore , we also consider C . paucidens is probably a junior synonym of C. chinensis but we could not make decision because we do not examine the holotype of C. paucidens directly.

Günther (1870) provided a more detailed redescription of C. chinensis than the short original description. Günther’s (1870) description is based on two specimens held in the BMNH, comprising one of the syntypes of C . chinensis and the holotype of O. polyodon . Ophisurus polyodon is a species described based on one specimen from western Sumatra, Indonesia . Based on YH’s observation of the holotype of O. polyodon , the origin of the dorsal fin is positioned anterior to the vertical through the gill opening. Therefore, this nominal species is not C. chinensis when focusing on the position of the dorsal fin. The nominal species of Cirrhimuraena have been described based on a limited number of specimens, ranging from one to three specimens, and have never undergone taxonomic reassessment. Therefore, it is desirable to conduct taxonomic reassessment in the future, including the reevaluation of diagnostic features for species identification.

Cirrhimuraena chinensis is a common snake eel in southern China, regarded as an edible resource around the coastal area of Fujian Province (H.-C. Ho, personal communication). Although it is also recorded from Philippines ( McCosker 2014) and Indonesia ( Miesen et al. 2016), recent genetic analysis indicated that “ C. chinensis ” from Indonesia made a different clade from that of the population of China ( Mohapatra et al. 2021: fig. 4). Therefore, records from East Asia were only included in the distribution of C. chinensis .

The present specimen represents the first record of the species from Japanese waters. The new standard Japanese name “Gotenba-umihebi” is derived from the collection locality, one of the famous fields of claim digging around Ise Bay.

Comparative materials. Cirrhimuraena chinensis : BMNH 1851.12. 27.228, 1, syntype (1 of 2 but another missing), 181 mm TL, locality unknown (? China); KMNH VR 100619, 5, 157–183 mm TL, near Kinmen Island, Taiwan, close from mainland of China; NMMB-P24689 , 1, 289 mm TL, NMMB-P34128 , 1, 239.9 mm TL, Dong-gang , southwestern Taiwan; NMMB-P37658 , 5 , 226–285 mm + (all tip of tail damaged), Matsu Island, Matsu Islands, northwestern Taiwan . Chirrhimuraena paucidens : CAS-SU 24326 View Materials , holotype (only by photographs), 195 mm TL (measurement from the original description), Hoihow , Haina, southern China . Cirrhimuraena taenioptera : BMNH 1867.11 . 28.321, 1, syntype (1 of 3 but others missing), 295 mm TL, Java or Makassar , Sulawesi, Indonesia . Jenkinsiella nectura : CAS-SU 9984 View Materials , holotype (only by photographs), 191 mm TL (measurement from the original description), Cavite, Luzon Island , Philippines . Ophisurus polyodon : BMNH 1867.11 . 28.263, holotype, 278 mm TL, Priaman , Sumatra, Indonesia .