Careproctus narilobus, Stein, David L., 2012

Stein, David L., 2012, A Review of the Snailfishes (Liparidae, Scorpaeniformes) of New Zealand, Including Descriptions of a New Genus and Sixteen New Species, Zootaxa 3588, pp. 1-54 : 9-11

Careproctus narilobus n. sp.

Figs. 5 , 6

Holotype. NMNZ P.047479, female, 146 mm SL, 163 mm TL, 42°36.50ʹ S, 179°40.62ʹ E, central northern Chatham Rise, Hikurangi Plateau, 13 June 2010, R/V Tangaroa, Stn. TAN 1008/085, 1832–1837 m. NMNZ P.047479/1, cleared and stained right pectoral girdle.

Diagnosis. Vertebrae 60, dorsal fin rays 51, anal fin rays 45, pectoral fin rays 37, caudal rays 12. Head 22, disk 4, anus-anal fin 28% SL; each nostril with a distinct dorsoposterior flap or lobe. Body brown, fins blackish.

Description. Counts. V 60, D 51, A 45, C 12, P 37, radials 4, pc 4, pores 2–5–6–2. Ratios. HL 22.5, HW 19.0, sn 8.2, E 5.4, orbit 6.5, uj 7.3, go 7.8, UPL 16.6, LPL 14.9, md 9.6, disk 3.5, da 4.2, preD 30.7, preA 45.4, sna 18.8, ma 16.9, aAf 27.5. In % HL: HW 84.2, sn 36.2, E 24.0, orbit 28.9, io 45.6, uj 32.2, go 34.7, UPL 73.5, LPL 66.0, md 42.8, disk 15.5, preD 136.2, preA 201.5, sna 83.3, ma 75.1, aAf 122.2.

Head relatively large and heavy, dorsal profile rounded, its length more than 1/5 SL, its width slightly less than its length. Snout blunt, rounded, its length about 1 1/4 times orbit, not projecting anterior to upper jaw. Nostrils single, about level with middle of pupil, distance anterior to eye about 1/2 eye length. Each nostril with a distinct skin flap along dorsoposterior margin. Eye large, about 1/4 HL, orbit well below dorsal profile of head; interorbital region broad, a little less than half HL. Mouth horizontal, terminal, upper jaw reaching posteriorly to below mid eye. Lower jaw length equal to upper, not included. Teeth slender sharp canines in both jaws, forming dense narrow bands 4–5 teeth wide, consisting of perhaps 35 highly irregular oblique rows each. Innermost teeth distinctly larger, fanglike. A narrow diastema present at symphysis of upper jaw, absent in lower jaw. Gill opening about 1/3 HL, above pectoral or extending in front of dorsal pectoral fin ray. Opening extends above opercular flap, curving posterodorsally almost to level of upper edge of eye. Opercular flap long, extending well posterior to bases of upper pectoral fin rays; broad, blunt, almost square at tip, its lower margin almost horizontal. Cephalic pores tiny, 2–5–6–2. Chin pore pair widely separated by a distance equal to about 6% HL; suprabranchial pores two, above and behind gill flap. Many free neuromasts scattered on head, especially around nostrils.

Pectoral fin rays divided into upper and lower lobes, notch shallow, almost absent in external view. Dorsalmost pectoral fin ray below lower margin of orbit, but well above posterior corner of upper jaw and mouth. Rays on right side 37 (23+9+5). Upper fin lobe reaching about 2/3 of distance to end of abdominal cavity, lower lobe short, its rays gradually increasingly free, reaching to below end of opercular lobe; base of anteriormost (lowest) ray below corner of mouth and anterior margin of eye. Notch rays unusually numerous, slightly more widely spaced than upper lobe rays, indistinct from those of lower lobe, spacing becoming gradually wider then narrower ventrally. Radials 4 (3+1), round, R1, R2 with crescent opposing notches, R3 dorsally notched, R4 round, unnotched, distant from R3, very close to coracoid. Large foramina present between scapula–R1, R1–R2, R2–R3. Scapula with ventral lunate notch, helve short, relatively small. Coracoid triangular, helve short.

Body deepest over middle of upper pectoral lobe, tapering evenly and slowly to caudal fin. Disk small, oval, slightly cupped, its width slightly less than its length; margin thin, edge fragile; structure visible through skin. Disk length a little more than half diameter of orbit, just behind eye. Distance from posterior margin of disk to anus slightly greater than disk length. Predorsal fin length longer than head, preanal length less than half SL, twice HL. Vertebrae 10+50. Dorsal fin origin between vertebrae 5–6. Anterior dorsal fin rays somewhat shorter than those in mid-fin, no anterior rudimentary rays present. Anal fin origin between vertebrae 12–13. Pyloric caeca ventral in body cavity; thick, closely attached, of various sizes. Stomach thin walled. Three pair of pleural ribs present. Hypural plate single, suture evident. Caudal rays 1+5/5+1, dorsal and anal fin overlap with caudal fin very short, almost absent. Skin thin, not easily torn.

Fresh color completely black, darker on head, abdomen, and fins. Color in alcohol: head and body brown, abdomen darker owing to black-brown peritoneum visible through skin. Pectoral and longitudinal fins blackish, edges of fins and lower pectoral rays black. Disk reticulated black on white. Orobranchial cavity pale, black dotted; peritoneum black-brown (visible through body wall), stomach pale with fine blackish veining, pyloric caeca pale.

The holotype has ripe 4.7 mm eggs.

Distribution. Known only from a single specimen taken on the northern Chatham Rise at a little more than 1800 m.

Etymology. The specific epithet narilobus from naris, Latin for nostril, and lobus, lobe, to denote the posterior tissue flap associated with the nostril.

Comparisons. The new species is a member of the subgenus Careproctus ( Andriashev 2003 and see above). Although unmistakably different, C. narilobus could most likely be confused with C. novaezelandiae in general shape, number of vertebrae and pectoral and caudal fin rays, pectoral girdle structure (radials 3+1, three foramina, notched scapula), and length and position of gill opening (above pectoral fin). However, it differs in presence of nasal flaps (vs slightly thickened rim), body color (dark vs pale), stomach color (pale vs pale with black reticulations), tooth shape (only sharp canines vs inner teeth trilobed), more vertebrae (60 vs 53–54), shorter head (22 vs 24–30% SL), much shorter disk (16 vs 20–25% HL), and other characters. Its high number of pectoral fin rays, pectoral girdle structure (notched radials), and nasal flaps distinguish it from all other Southern Ocean species.

Comments. Pectoral girdle structure suggests that this species may be closely related to C. novaezelandiae , although the differences in tooth shape (canine vs trilobed) suggest otherwise.

Figures

FIGURE 5. Careproctus narilobus n. sp. Holotype. NMNZ P. 047479, 146 mm SL. A. lateral view; B. NMNZ P. 047479 / 1 right pectoral girdle; C. enlarged view of nostril.

FIGURE 6. Careproctus narilobus n. sp. Holotype. NMNZ P. 047479, 146 mm SL. Lateral view of fresh specimen. (Photo by P. Marriott, NIWA)