Paraliparis tangaroa, Stein, 2012

Stein, David L., 2012, Snailfishes (Family Liparidae) of the Ross Sea, Antarctica, and Closely Adjacent Waters 3285, Zootaxa 3285, pp. 1-120 : 103-107

Paraliparis tangaroa n. sp.

Figs. 73, 74

Holotype. NMNZ P.045475, ripe female, TL, SL unknown; 49 mm HL, 133 mm preA, Iselin Seamount, Ross Sea, 71°00.0' S, 179°30.0' W, F/ V San Aotea II, Stn. OBS 2731/077, 20 January 2009, 966– 1153 m. Last part of tail missing. NMNZ P.045475/1, cleared and stained right pectoral girdle.

Diagnosis. Teeth uniserial for more than posterior half of premaxilla, and almost all of mandible. V 14+?, P 20, C? Dorsal fin with two rayless anterior pterygiophores, the first between V 4–5, first ray between V 6–7. Chin pores unusually closely paired, their distance about 1% HL; anterior crescent-shaped tissue fold possibly present. Predorsal length about 124% HL. Pectoral fin notch rays rudimentary. Radials 4 (1+1+1+1). Subdermal gelatinous tissue not well developed. Body color white.

Description. Counts. V 14+?, number unknown; D, A, C unknown. P 19?–20 (14+2–3+3–4), radials 4 (1+1+1+1), pc unknown, pore formula unknown. Ratios. In % HL: sn 27.1, E 18.0, orbit 27.8, io 44.9, uj 36.3, go 16.3, preD 123.7, preA 271.8, aAf 194.7, UPL 64.9, LPL 68.8, cp 1.0.

Head short and deep, dorsal profile rising in an even curve through flattened interorbital region to deepest part of body over mid-abdomen. Snout short, about 1/4 head. Nostrils porelike, immediately anterior to orbit by less than 25% orbit diameter, on a horizontal about through center of pupil. Mouth horizontal, subterminal, oral cleft reaching below anterior half of orbit. Teeth simple, blunt, stout canines, uniserial in posterior 1/2–2/3 of upper jaw. Premaxillary teeth uniserial posteriorly for about 17 teeth, then forming about 11 gradually longer oblique curved rows of up to four teeth each near symphysis. Mandibular teeth smaller, uniserial for about 50 teeth, then anteriorly about 10 oblique rows of up to five teeth each near symphysis. In both jaws, teeth gradually smaller towards symphysis. Symphyseal gap present in both jaws, wide in upper jaw, narrower but clear in mandible. Eye prominent, pupil very large, almost equal to eye diameter. Gill opening completely above pectoral fin base, almost 1/6 head;

.

pores chin

.

c

;

1

/

045475

.

P

NMNZ

,

girdle pectoral

.

b

;

view lateral

.

a

;

unknown

SL

,

045475

.

P

NMNZ

,

Holotype

.

sp

.

n

tangaroa

Paraliparis

.

73

FIGURE opercular flap clearly developed, its tip triangular, supported by broad, horizontal but dorsally curved opercle. Chin pores not in a pit, anterior tissue fold possibly present; distance separating them narrow, pores almost touching, inter-pore distance about 1% HL, not more than one pore diameter apart. Pore formula unknown, remaining pores moderately large, clearly visible.

Pectoral fins short, about 2/3 HL, longest ray of upper lobe not reaching midpoint of abdominal cavity. Uppermost ray on horizontal with lower margin of orbit. Upper lobe rounded, of 14 rays, notch rays two or three, rudimentary, short, damaged but probably filamentous. Lower lobe of three rays, insertion of lowest ray below cheek, distinctly anterior to gill opening; lower lobe rays reaching posteriorly to below middle of upper lobe or slightly farther. A wide gap present between lower pectoral fin lobes. Right pectoral girdle with 4 (1+1+1+1) almost round unnotched radials, R1, R2 larger, R3 smallest, R4 intermediate in size between R1-2 and R3. Fenestrae and notches absent. Distance between R1 and R2 noticeably less than that between R2–R3 and R3–R4. Scapula like a double bladed axe, the basal plate larger and broader than the helve. Coracoid with a long, slender helve, basal notch present.

Body thick, deepest well behind head. Dorsal fin anteriormost ray insertion between vertebrae 6–7; two anterior rudiments present, insertion of the first between vertebrae 4–5. Anal fin insertion between vertebrae 14–15. Dorsal and anal fins deepest at about 4/5 of SL posterior. Anus slightly posterior to bases of lower pectoral fin lobe rays, below end of suborbital stay. Peritoneum visible through white body wall but not strongly black in outside view. Pyloric caeca partially deteriorated, but remaining caeca large, very flat, easily damaged. Hypural complex fused, slit absent. Caudal fin unknown. SECM apparently not well developed. Skin thick, fibrous.

Color of body in alcohol white, head pale brownish. Mouth gray, tongue paler; branchial cavity blackish, peritoneum black, stomach and pyloric caeca pale.

The specimen is a ripe female with eggs up to 3.8 mm diameter.

Distribution. Known only from a single specimen collected on Iselin Seamount in the Ross Sea at 966–1153 m depth.

Etymology. Named after the Maori god of the sea, Tangaroa , responsible for all sea creatures. To be treated as a noun in apposition.

chin

.

b

;

view lateral

.

a

;

.

sp

.

n

edentatus

Paraliparis as

,

29

.

Fig

:

1986

,

Andriashev

From

.

SL

mm

68

.

–

81

,

caeca

266

ISH pyloric

1916

.

and

Regan stomach

.

terraenovae 46830; ZIN

d

Paraliparis girdle

,

75

.

pectoral

FIGURE; c

. pores

Comparisons. This specimen is similar to P. plicatus in most of its proportions, and in the few counts that can be made. However, it differs significantly in the dorsal fin insertion (between V 4–5 if the two anterior fin rudiments are included, between V 6–7 if not, vs between V 9–10), the associated shorter predorsal length (123 vs 196% HL), the greater anus-anal fin distance (195 vs 178% HL), shorter snout to anus distance (85 vs> 91% HL), much closer chin pores (almost touching, distance between them 1 vs 2% HL), and smaller eye (18 vs 22% HL). Its pectoral girdle differs from that of P. plicatus in having different radial spacing (1+1+1+1 vs 3+1), somewhat larger radials, and a clear basal notch in the coracoid (vs a dorsal slit). In addition, it was collected at a shallower depth (<1153 vs 1431–1990 m). Although some differences in morphometric characters (not those above) might be explained by its poor condition, the anterior dorsal fin origin and the characters given above cannot be. It similarly could be mistaken for P. alius , but differs in number of abdominal vertebrae (14 vs 11), anal fin insertion (vertebrae 14–15 vs 12–13), radial arrangement (1+1+1+1 vs 3+1), basally notched coracoid (vs unnotched), upper pectoral fin lobe length (65 vs 74% HL), shorter predorsal fin length (124 vs 174% HL), anus-anal fin length (195 vs 174% HL), distance between chin pores (1 vs 3% HL), and presence of anterior pterygiophores lacking dorsal fin rays (vs none). All three species are represented by females of similar size ( P. tangaroa : 49, P. alius : 48, P. plicatus : 42 mm HL), so sexual dimorphism and allometric growth are unlikely. Therefore, the species is described as new.