Chauligenion camelopardalis McCosker & Okamoto, 2016

McCosker, John E. & Okamoto, Makoto, 2016, Chauligenion camelopardalis, a New Genus and Species of Deepwater Snake Eel (Anguilliformes: Ophichthidae) from the East China Sea, Proceedings of the California Academy of Sciences 63 (9), pp. 321-328 : 326-328

Chauligenion camelopardalis McCosker & Okamoto , sp. nov.

New English name: Giraffe- spotted snake eel; New Japanese name: Kirin-umihebi

Figures 1–6

MATERIAL EXAMINED.— Holotype, NSMT-P 125489, 407 mm TL, female, from 27°15ʹ00ʺN, 125°45ʹ00ʺE, East China Sea, west of Okinawa, captured by trawl at 150 m, on 25 Nov. 2014.

DIAGNOSIS.— An elongate ophichthine with the following characteristics: tail 53% of TL; snout and tail tip pointed; chin in advance of snout tip; dorsal fin arising above gill opening; median fins low; pectoral fin absent; eye moderate, 10.8 in head, behind middle of upper jaw; cephalic pores small but apparent, 3 preopercular and 3 supratemporal; teeth small, conical, numerous and densely packed on jaws, irregularly biserial on vomer; coloration yellowish-tan overlain with 2 rows of 70–75 eye-sized brown spots; vertebral formula 9/82/186.

COUNTS AND MEASUREMENTS OF THE HOLOTYPE (in mm).— Total length 407; head length 33.6; trunk length 158.4; tail length 215; body depth at gill openings ca. 9.3; body width at gill openings ca. 6.9; body depth at branchial basket ca. 7; body width at branchial basket ca. 8; body depth at anus ca. 10; body width at anus ca. 8; origin of dorsal fin 32.6; gill-opening length ca. 2.8; isthmus width ca. 5; snout length 7.3; tip of snout to tip of lower jaw 0.3; upper-jaw length 13.2; eye diameter 3.1; interorbital distance 1.6. Total left-lateral pores 171, 8–10 above branchial basket, 83 before anus, last pore 13 mm before tail tip. Vertebral formula 9/82/186.

DESCRIPTION (other characters those of the genus).— Body elongate, depth at gill openings 44 in TL, cylindrical in head and trunk, laterally compressed in tail region. Head and trunk 2.2 and head 12.1 in TL. Snout acute, without a median groove on its underside. Jaws elongate, capable of closing completely; center of eye above posterior 1 ⁄ 3 of upper jaw. Lower jaw extended slightly beyond tip of snout. Anterior nostrils open well above upper lip with a small barbel in anterodorsal corner, without a tube or marginal extensions; posterior nostril in upper lip, not entering mouth, covered by a flap and not obvious, its posterior margin abutting anterior margin of orbit. Eye moderate, 10.8 in head and 4.3 in upper jaw, its center above posterior 2 ⁄ 3 of upper jaw, its rear margin in advance of rictus. Interorbital region narrow, slightly elevated. Gill openings low lateral, vertical, not converging forward, opening about twice eye diameter. Pectoral fins absent. Dorsal-fin origin above gill opening. Median fins low, extending to ½ HL before pointed end of caudal fin.

Head pores minute but apparent ( Fig. 5 ); supraorbital pores 1 + 3, infraorbital pores 5 + 3, 5 pores along mandible, 3 pores overlying preopercle, 3 supratemporal pores. A single temporal and interorbital pore. Two infraorbital pores between anterior and posterior nostrils. Approximately 171 lateral-line pores present, 7–10 (7 left, 10 right) above branchial basket, 83 before mid-anus, last pore about 13 mm before tail tip.

Teeth ( Fig. 6 ) small, conical, numerous and densely packed. Anterior ethmovomerine teeth the largest, slightly retrorse, followed by 6–7 irregular rows of smaller teeth, followed by a row of 25 smaller vomerine teeth. Teeth of maxillary and mandibular in patches, becoming smaller and more numerous posteriorly. Maxillary patch is approximately 150 teeth which become smaller and more densely packed posteriorly. Mandibular patch is approximately 250 teeth, becoming smaller and more densely packed posteriorly. (Teeth of the single specimen too difficult to accurately examine without dissection.)

Gill arches ( Fig. 3 ) mostly cartilaginous: basibranchials 1–4 cartilaginous; hypobranchials 1–4 cartilaginous; ceratobranchial 1 cartilaginous, 2–4 ossified, 5 minute and cartilaginous; epibranchial 1 cartilaginous, 2–4 ossified; infrapharyngobranchials 2–3 ossified; upper and lower pharyngeal tooth plates with 5 nearly regular rows of small, conical, densely packed and slightly retrorse teeth, the upper pharyngeal tooth plate with 5 longitudinal rows of ca. 15 teeth, plates closely sutured but not fused; the lower pharyngeal tooth plate with 20–25 conical teeth in 5 irregular longitudinal rows. Teeth comparable in size and appearance to those of jaws.

Body coloration in ethyl alcohol (coloration of fresh specimen shown in Figs. 1–2 ) uniform yellowish-tan, overlain with two rows of distinctive uniformly brown spots equal to or slightly smaller than orbit. Upper row with 70–75 round spots arranged slightly closer than their interspaces, meeting but not crossing at dorsal midline. Lower row has smaller and more numerous spots centered along lateral line that become enlarged in mid-trunk region. Snout spots much smaller, increasing in size behind orbit. Median fins pale. Cheeks, chin, ventral surface and peritoneum overlain with fine brown speckling. Anal opening within a pale spot. Throat and palate pale. Lateral-line pores within pale spots. Tail tip pale like ground color.

SIZE.— Known only from the holotype, a 407 mm TL female with maturing ova .

ETYMOLOGY.— From the Latin camelopardalis (giraffe), in reference to its coloration, to be treat- ed as a noun in apposition.

DISTRIBUTION.— Known only from the holotype, captured by trawl at 150 m depth in the East China Sea .

REMARKS.— The holotype of the new species is a female and becoming sexually mature. The lateral-line pores above the branchial basket are abnormally distributed for an ophichthid; ( Fig. 5 ); they appear to be in pairs rather than equally spaced. The remainder of the lateral-line pores along the flank appear to be normally spaced.

The new species would not be mistaken for any known ophichthid, on the basis of its elongate body, extended lower jaw, minute dentition, its anterior nostril location, distinctive coloration, and its lack of a pectoral fin.

We look forward to the capture of additional specimens of this remarkable snake eel.

Figures

FIGURE 1.Holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL, photographed soon after capture and before preservation. Arrows indicate origin of dorsal and anal fins.

FIGURE 2. Head of holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL, photographed soon after capture and before preservation.

FIGURE 3. Gill arches (interior view, cut longitudinally along dorsal surface and spread laterally) of holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL. Bone is stained red and cartilage is blue.

FIGURE 4. Radiograph of head of holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL.

FIGURE 5. Schematic illustration of head of holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL.

FIGURE 6. Schematic illustration of dentition (upper jaw left, lower jaw right) of holotype of Chauligenion camelopardalis sp. nov., NSMT-P 125489, female, 407 mm TL.