A new arrowtooth eel of genus Meadia (Synaphobranchidae: Ilyophinae) from Vietnam, South China Sea Author Vo, Van Quang Institute of Oceanography, Vietnam Academy of Science and Technology, Vietnam & Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Vietnam. Author Ho, Hsuan-Ching National Museum of Marine Biology & Aquarium, Pingtung, Taiwan & Institute of Marine Biology & Aquarium, National Dong Hwa University, Pingtung campus, Taiwan Author Dao, Ha Viet Institute of Oceanography, Vietnam Academy of Science and Technology, Vietnam Author Tran, Hoa Hong Thi Institute of Oceanography, Vietnam Academy of Science and Technology, Vietnam text Zootaxa 2021 2021-04-08 4952 1 181 191 journal article 7379 10.11646/zootaxa.4952.1.11 9bcb7dd2-d3b9-4fbd-9912-6e44b3dea144 1175-5326 4671590 6D19FD36-64CB-4AF0-8ED6-49E9DE07233F Meadia roseni Mok, Lee & Chan, 1991 Figs. 3B , 4B , 5B ; Table 1 Meadia roseni Mok, Lee & Chan, 1991:39 , figs. 1–3 ( type locality: off Tongkang [Dong-gang], southwestern Taiwan , 22°21'05"N , 120°12'46"E , depth 1020 m ). Ho & Shao, 2011:22 . Ho et al. , 2015b:179 . Ho et al. , 2015c:8 . Description. Head with a clear hump behind eye. Dorsal-fin origin slightly behind pectoral-fin base. Anal-fin origin about 0.6–0.7 HL behind head. Middle of eye through posterior third of upper jaw. Posterior nostril with low rim and its margin bearing many fringes. Numerous cirri or papillae on snout and chin, gradually becoming scattered on posterior portion of head. Gill opening against lower end of pectoral-fin base ( Figs. 3B , 4B ). Head pores: SO 1 (ethmoid) + 3, 3 at tip of snout and the fourth above upper margin of eye; IO 6, 1 (adnasal) at posterodorsal corner of anterior nostril, 2 between nostrils and 2 below eye, the sixth above posterior end of rictus; F 0; POM 10 or 11 (mainly 11), the penultimate pore 0.5–1 eye diameter behind rictus and the last 1.5–2 eye diameter behind rictus. ST 0. Lateral-line pores: head 9 or 10; PDLL 14 or 15; PAL 30–32. Numbers of dorsal-fin rays before anal-fin origin 37–46. FIGURE 5. Posterior portion of tail showing the coloration of fins. A. Meadia abyssalis , NMMB-P15513, 336 mm SL, leftright reversed. B. Meadia roseni , NMMB-P25976, 429 mm TL. C. Meadia minor sp. nov. , from holotype. Not to scale. Anterior to left. Vertebrae: PDV 15–16, PAV 31–35, PCV 62–65, TV 200–204, and MVF 16-32-202. Tooth pattern: an oval patch of 14–20 moderately large, stout teeth on intermaxillary; followed by a long patch of various-sized teeth on vomer, which has about 11–15 enlarged and stout teeth, most teeth with a cutting edge, followed by 4–7 much smaller stout teeth posteriorly. Maxilla with a long band of about 4 rows of pointed teeth, those on outer row smallest, those on inner rows gradually larger. Lower jaw with about 4 rows of stout teeth anteriorly, gradually becoming 2 rows posteriorly, those on outer row smallest, those on inner row gradually becoming larger, most teeth with a cutting edge at tip. Coloration. In both fresh and preserved specimen, body uniformly grayish brown to dark brown, generally darker than that of M abyssalis . Anterior portion of dorsal and anal fin (about half of the fin) grayish brown with broad pale margin, gradually becoming darker and the margins becoming narrower, darkened at about one head length from posterior end; caudal fin black ( Figs. 3B , 4B , 5B ). Peritoneum pale with black pepper dots, stomach and intestines pale. TABLE 1. Morphometric and meristic data of three Meadia species.

M. minor sp. nov.	M. abyssalis	M. roseni
Holotype	Types	Non-types	Non-types
Total length (mm)	307	273–330 (n=8)	256–595 (n=4)	323–575 (n=4)
Proportions (% TL)	Mean (range)	SD	Mean (range)	Mean (range)
Head length (HL)	11.4	11.0 (10.6–11.4)	0.3	11.3 (10.3–12.0)	13.9 (13.6–14.3)
Preanal length	33.9	33.4 (32.1–35.6)	1.1	17.2 (15.5–18.2)	22.8 (22.0–23.5)
Predorsal length	11.9	11.6 (11.1–12.0)	0.3	12.7 (11.4–13.8)	15.6 (15.4–15.9)
Trunk length	22.4	22.4 (21.3–25.0)	1.1	5.9 (5.3–6.5)	8.9 (8.2–9.3)
Tail length	66.1	66.6 (64.4–67.9)	1.1	82.8 (81.8–84.5)	77.2 (76.5–78.0)
Body depth	4.1	3.9 (3.6–4.1)	0.2	5.4 (5.0–6.2)	5.4 (4.8–6.0)
Body width	3.4	3.3 (3.0–3.7)	0.3	2.6 (2.2–3.0)	3.3 (3.1–3.6)
Proportions (% HL)
Snout length	21.4	22.7 (21.4–23.7)	0.9	29.9 (28.4–31.6)	29.2 (28.0–31.2)
Eye diameter	10.8	9.9 (8.3–10.9)	0.9	12.0 (10.7–14.1)	9.3 (8.5–9.8)
Upper-jaw length	41.0	39.9 (38.4–41.1)	1.0	42.1 (37.8–46.1)	46.4 (44.3–49.4)
Interorbital width	21.1	21.4 (19.9–22.1)	0.7	17.1 (14.4–18.7)	16.3 (16.0–17.0)
Gill-opening width	5.4	6.2 (5.4–7.0)	0.6	8.7 (8.3–9.1)	9.8 (8.6–10.6)
Interbranchial width	26.2	24.2 (20.7–26.2)	1.7	17.1 (16.8–17.2)	12.0 (11.4–13.1)
Pectoral-fin length	25.1	23.1 (21.1–25.1)	1.2	26.1 (21.9–28.7)	23.0 (21.3–26.8)
Meristics
SO	3	3	3	4
IO (including AD)	4	4	6	6
POM	7	7	8	10–11
F	0	0	0	0
ST	0	0	0	0
HLL	2	2–3	3–4	9–10
PDLL	4	3–4	5–6	14–15
PALL	39	35–41	14–16	30–32
DR-AF	86	83–100	22–27	37–46
PDV	7	6–8	10–11	15–16
PAV	32	32–35	19	31–35
PCV	45	44–46	55–60	62–65
TV	122	118–122	174–179	200–204
MVF	7-33-121	11-19-176	16-32-202

Remarks. The lateral-line pores are more numerous and are rather close to each other in M. roseni compared to the two other congeners. In general, M. roseni has more teeth on jaws, intermaxillary, and vomer and a darker body color compared to M. abyssalis .