Validity of Scolecenchelys aoki, with a redescription of Scolecenchelys gymnota (Anguilliformes: Ophichthidae)

• Published in: Ichthyological research Vol. 59; no. 2; pp. 179 - 188
• Main Authors: Hibino, Yusuke, Kimura, Seishi, Hoshino, Kazuo, Hatooka, Kiyotaka, McCosker, John E
• Format: Journal Article
• Language: English
• Published: Japan Springer-Verlag 01.04.2012; Springer Japan; Springer Nature B.V
• Subjects: Anguilliformes; Animal Systematics/Taxonomy/Biogeography; anus; Biomedical and Life Sciences; Ecology; eel; eyes; Fish; Freshwater & Marine Ecology; geographical distribution; Life Sciences; Muraenichthys; Muraenichthys gymnotus; Ophichthidae; Physiology; Sphagebranchus; Teeth; type collections; vertebrae; Zoology; Red Sea; South Africa; Pacific Ocean; Ryukyu Archipelago; Samoa; I, Indo-Pacific; ISW, Red Sea; ISEW, Japan, Nansei-shoto, Okinawa; ISE, Pacific, Samoa; Myrophinae; Indo-Pacific; Ophichthidae
• ISSN: 1341-8998; 1616-3915
• DOI: 10.1007/s10228-011-0269-4

The myrophine ophichthid fishes (worm eels) Muraenichthys aoki Jordan and Snyder 1901 and Muraenichthys gymnotus Bleeker 1857 are redescribed as valid species of Scolecenchelys based on the types and non-type specimens collected from the Indo-Pacific. Because both species are similar to each other in having acute snouts, the posterior margin of the eye before the rictus, and their dorsal-fin origins located slightly posterior to a vertical line through the anus, Scolecenchelys aoki has usually been regarded as a junior synonym of Scolecenchelys gymnota. However, S. aoki is clearly distinguishable from S. gymnota by having a median groove on the ventral side of snout (absent in S. gymnota), uniserial maxillary teeth in smaller specimens (<200 mm TL; vs. biserial), three infraorbital sensory pores at postorbital area (vs. two), and more numerous vertebrae (56–65 in predorsal vs. 51–57; 53–58 in preanal vs. 47–52). Scolecenchelys aoki is restricted to Japanese waters and regarded as a senior synonym of Muraenichthys borealis Machida and Shiogaki 1990. Scolecenchelys gymnota is widely distributed in the Indo-Pacific, from South Africa and the Red Sea to Samoa, north to Okinawa, Japan. Sphagebranchus huysmani Weber 1913 and Muraenichthys fowleri Schultz 1943 are synonymized under S. gymnota.