Sympenchelys taiwanensis, Hibino, Yusuke, Ho, Hsuan-Ching & Kimura, Seishi, 2015

Hibino, Yusuke, Ho, Hsuan-Ching & Kimura, Seishi, 2015, A new genus and species of worm eels, Sympenchelys taiwanensis (Anguilliformes: Ophichthidae: Myrophinae), from the northwestern Pacific Ocean, Zootaxa 4060 (1), pp. 41-48 : 44-47

Sympenchelys taiwanensis sp. nov.

New English name: Taiwanese Worm Eel ( Figs. 1–6 ; Table 1 )

Holotype. NMMB-P 22188, 258.8 mm TL, female, Dong-gang, Taiwan, 4 December 2014, bottom trawl, collected by H.-C. Ho.

Paratypes. Four specimens, 165.0–279.0 mm TL. ASIZP 60198, 279.0 mm TL, female, Dashi, Yilan, Taiwan, 15 March 1999, bottom trawl, collected by P.-L. Lin; FRLM 49936, 187.5 mm TL, sex unknown, Dong-gang, Taiwan, 3 November 2011, bottom trawl, collected by H.-C. Ho; NMMB-P 17554, 194.0 mm TL, female, Donggang, Taiwan, 9 November 2012, bottom trawl, collected by H.-C. Ho (cleared-and-stained after measurement); NSMT-P 123778 (donated from NMMB), 165.0 mm TL, sex unknown, Dong-gang, Taiwan, 10 March 2015, collected by H.-C. Ho.

Diagnosis. A species of the genus Sympenchelys with the following combination of characters: tail 65–66% TL; dorsal-fin origin anterior to mid trunk; lateral-line pores before anus 44–47; predorsal vertebrae 26–28, preanal vertebrae 43–51, and 152–164 total; MVF 27-48-160.

Description. Counts and measurements are shown in Table 1 , and characters given in “Description” of the genus are not repeated. Head moderate in size. Snout blunt, equal to or slightly longer than twice eye diameter; distance from tip of snout to anterior tip of lower jaw almost equal to half of eye diameter; no median groove ventrally on snout; eyes small, covered by a transparent skin; teeth on upper jaw biserial, teeth of inner row larger than outers ( Fig. 4 ); teeth on lower jaw uniserial; intermaxillary teeth slightly shorter than jaw teeth, arranged semicircularly; vomerine teeth large, arranged uniserially; interorbital region convex without a median groove; arrangement of sensory pores on head as follows ( Fig. 5 ): one + four on supraorbital, three + two on infraorbital (one between anterior and posterior nostrils), six on lower jaw, three on preopercle, and two on supratemporal; single median interorbital and mid-temporal pores; lateral-line pores small but obvious, almost complete except for near tip of tail.

Coloration. Freshly caught specimens ( Fig. 2 ) uniformly yellowish green with numerous tiny melanophores. Median fins with paler margins, posterior part darkish yellow. Anterior head reddish and anterior region of abdomen silver white. Preserved in 50% isopropanol or 70% ethanol, head and body uniformly yellowish brown or pale whitish brown, small dark spots distributed on lower jaw, tail, and upper half of head and trunk. All fins pale brown.

Holotype Paratypes Unidentifiable

juvenile specimen Distribution and ecological note. Known from northeastern and southwestern Taiwan, possible depth range 100– 300 m.

Etymology. The scientific name “ taiwanensis ” is derived from the type locality.

Remarks. Although depth and habitat of adults is unknown, the type series were collected by bottom trawl with green-eyes ( Chlorophthalmus spp.), lizardfishes ( Saurida spp.), conger eels, and some shallow water grenadiers ( Coelorinchus spp.). It is expected that their benthic life occurs at depths between 100 and 300 meters.

A juvenile specimen (KPM-NI 23506, 51.4 mm TL) similar to the new species in general appearance and in the shape of its jaw teeth was collected from central Japan. The specimen also agrees well S. taiwanensis in its preanal vertebral count and cephalic sensory-pore counts ( Table 1 , Fig. 6 ). However, it lacks paddle-shaped neural and haemal spines and has uniserial teeth on its upper jaw ( Fig. 4 c). Although the differences between the juvenile specimen and the new species are likely to be considered as ontogenetic variation, we cannot conclude that it is conspecific with S. taiwanensis . Medium-sized specimens of the new species or molecular data are needed.

Comparative materials. Unidentifiable juvenile specimen: KPM-NI 23506, 51.4 mm TL, juvenile, 0 m (near the surface), Osezaki, Numazu, Shizuoka Prefecture, Japan, 14 November 2008, collected by R. Minemizu. Ahlia egmontis : FMNH 99266, two, 252–392 mm TL, Belize, Caribbean Sea. Asarcenchelys longimanus : MNHN B. 2994 (paratype), ca. 140 mm TL (damaged), off Belém, Brazil, western Atlantic. Glenoglossa wassi : CAS 47049 (holotype), 153.5 mm TL, Tutuila Island, American Samoa; USNM 378662, two of eight, 105.3–112.9 mm TL, Mindoro Island, Philippines. Mixomyrophis longidorsalis : HUJ 11651 (holotype), 77.0 mm TL, Israel, Red Sea. Neenchelys cheni : NSMT-P 69185, 358.5 mm TL, Nha Trang, Vietnam. Muraenichthys gymnopterus : RMNH. PISC. 7165 (holotype), 223.0 mm TL, Java, Indonesia. Muraenichthys hattae : FRLM 34541, 303.9+ mm, Owase, Mie Prefecture, Japan (cleared and stained). Muraenichthys schultzei : BMNH 1867.11.28.331 (holotype), 94.0 mm TL, Batavia, Java Island, Indonesia. Muraenichthys thompsoni : SU 20201 (holotype), 96.0 mm TL, Luzon Island, Philippines; NMMB-P 17508, 174.8 mm TL, Dong-gang, Taiwan; HUMZ 198661, 179.5 mm TL, Panay Island, Philippines. Myrophis microchir : CAS 28696, 109.3 mm TL, Guam. Neenchelys mccoskeri : NSMT- P 108567 (paratype), 311.0 mm TL, Shizuoka, Japan. Pseudomyrophis atlanticus : MNHN 1971-0041 (paratype), 238.0 mm TL, Congo, eastern Atlantic. Schultzidia johnstonensis : USNM 409172, 124.2 mm TL, Marquesas Islands, French Polynesia. Schismorhynchus labialis : ANSP 124362, two of 37, 112.6– 117.8 mm TL, Mombasa, Kenya. Scolecenchelys australis : AMS I.16266-001 (syntypes), three, 154.9–246.0 mm TL, Lane Cove River, New South Wales, Australia. Skythrenchelys macrostoma : BMNH 1867.11.28.313 (holotype), 223.0 mm TL, Ambon Island, Indonesia; BPBM 29320 (holotype of Skythrenchelys lentiginosa ), 163.1 mm TL, the Red Sea, Port Sudan Harbor. Skythrenchelys zabra : BPBM 38404 (paratype), 185.0 mm TL, Cobourg Peninsula, Northern Territory, Australia; CAS 51992, 136.5 mm TL, Negros Island, Philippines.

Figures

FIGURE 1. Caudal vertebrae of Sympenchelys taiwanensis sp. nov. a NMMB-P 17554, paratype, 194.0 mm TL (cleared-and-stained); b ASIZP 60198, paratype, 279.0 mm TL (soft-X ray photograph).

FIGURE 2. Fresh condition of Sympenchelys taiwanensis sp. nov., NMMB-P 22188, holotype, 258.8 mm TL, collected from Donggang, Taiwan. A, position of anus; D, origin of dorsal fin.

FIGURE 3. Magnification around left gill opening of Sympenchelys taiwanensis sp. nov., ASIZP 60198, paratype, 279.0 mm TL. Arrow indicates an extremely short dermal flap.

FIGURE 4. Teeth of Sympenchelys taiwanensis sp. nov. (a, b) and the unidentifiable juvenile specimen (c, d). a, b ASIZP 60198, paratype, 279.0 mm TL; c, d KPM-NI 23506, 51.4 mm TL, collected from Shizuoka Prefecture, Japan. Dotted circles indicate toothless holes.

FIGURE 5. Sensory pores on head of Sympenchelys taiwanensis sp. nov., ASIZP 60198, paratype, 279.0 mm TL. IO, infraorbital pores; LL, lateral-line pores; M, mandibular pores; PO, preopercular pores; SO, supraorbital pores; ST, supratemporal pores. Arrows indicate interorbital and median supratemporal pores.

FIGURE 6. Lateral view of the body (a) and head (b) of the unidentifiable juvenile specimen, KPM-NI 23506, 51.4 mm TL.

Tables

TABLE 1. Counts and measurements of Sympenchelys taiwanensis and the unidentifiable juvenile specimen.

	NMMB-P 22188	ASIZP 60198	NMMB-P 17554	FRLM 49936	NSMT-P 123778	KPM-NI 23506
Total length (mm)	258.8	279.0	194.0	187.5	165.0	51.4
Counts
Lateral-line pores before anus	49	44	47	48	47	47
Predorsal vertebrae	28	27	26	28	–	24
Preanal vertebrae	50	43	48	51	–	45
Total vertebrae	161	152	162	164	–	148
Measurements
As % of total length
Head length	12	10	12	12	12	14
Trunk length	23	24	23	23	23	23
Tail length	65	66	65	65	65	62
Predorsal length	21	21	20	21	19	23
Body depth at gill opening	3.2	3.6	3.0	2.4	3.3	2.9
Body depth at mid-anus	3.0	3.3	2.9	2.1	3.3	2.2
Body width at gill opening	1.9	1.7	1.6	1.1	2.2	1.6
Body width at mid-anus	1.6	1.5	1.6	1.1	2.3	1.5
As % of head length
Dorsal-fin origin to anus	113	118	123	116	129	101
Upper-jaw length	42	42	48	42	44	45
Length of mouth gape	32	32	38	33	33	34
Snout length	13	14	13	13	12	16
Eye diameter	5.5	5.4	7.0	7.1	8.4	6.4
Interorbital width	4.7	7.5	4.7	3.9	6.1	9.9
Gill-opening length	6.4	7.1	4.8	4.0	3.3	3.5
Body depth at gill opening	27	35	24	20	28	20
Body depth at mid-anus	26	32	23	17	28	16