Neenchelys gracilis Ho & Loh, 2015

Ho, Hsuan-Ching, Hibino, Yusuke & Huang, Jian-Fu, 2018, Note on rare snake eels (Anguilliformes: Ophichthidae) and additional data on three Neenchelys recently described from Taiwan, Zootaxa 4454 (1), pp. 200-214 : 211

Neenchelys gracilis Ho & Loh, 2015

Figure 6 ; Table 3

Neenchelys gracilis Ho & Loh, 2015:52 , figs. 1̅2 (type locality: off Dong-gang, Pingtung, Taiwan, China Sea, depth ca. 400 meters). Ho et al., 2015b:8. Ho et al., 2015c:170. Hibino et al., 2015:57 (in Key).

Specimens examined. Holotype. NMMB-P 22195 , 429 mm TL, off Dong-gang , Pingtung, 1 Nov. 2014 . Nontypes. NMMB-P 26438 , 393 mm TL, Dong-gang , Pingtung, 20 Jun. 2017 . NMMB-P 27447 , 500 mm TL, Donggang , Pingtung, 30 Aug. 2017 .

Diagnosis. A species of Neenchelys with the following combination of characters: pectoral fin minute, a tiny flap at upper corner of gill opening; many cirri on rim of anterior nostril; body cylindrical, body depth at gill opening 4.4¯6.5 times of HL, 66¯ 96 in TL; dorsal-fin origin at anterior third of trunk, 1.7¯1.9 times in HL behind gill opening; predorsal length 5.1¯6.0 in TL; head relatively short, 14.7¯ 16.1 in TL; trunk 3.0¯ 3.1 in TL; tail long, 1.6¯ 1.7 in TL. Total vertebrae 197¯204; VF 32-73-200. Cephalic lateral-line pores 11¯12; predorsal pores 32¯37; and preanal pores 71̄78. Body uniformly deep gray or dark brown.

Remarks. Although not overlapping with most values of the holotype, the two newly collected specimens show similar proportions with the holotype. The head length, predorsal length, preanal length, trunk length and snout length are slightly larger than these of the holotype ( Table 3). The meristic values are more variable, there are 30 predorsal vertebrae in the holotype, versus 35 (393 mm) and 30 (500 mm) in two other specimens; 78 preanal vertebrae, versus 69 and 73, respectively; 200 total vertebrae, versus 197 and 204, respectively. The head and lateral-line pores also varies, there are 5 mandibular pores in the holotype, versus 6 in two other specimens; 33 predorsal pores, versus 37 and 32, respectively; 78 preanal pores, versus 71 and 75, respectively. All these differences are considered as individual variation and the diagnosis of the species is revised accordingly. It also notable that one specimen (393 mm) has a frontal pore, whereas the other two have none. Same situation also found in our N. daedalus and the presence of absence of frontal pore is variable in these two species, a unique condition within the genus.

Figures

FIGURE 6. Neenchelys gracilis Ho & Loh, 2015. NMMB-P26438, 393 mm TL. A. lateral view. B. close view of head.