Notoliparis antonbruuni, David L. Stein, 2005

David L. Stein, 2005, Descriptions of four new species, redescription of Paraliparis membranaceus, and additional data on species of the fish family Liparidae (Pisces, Scorpaeniformes) from the west coast of South America and the Indian Ocean., Zootaxa 1019, pp. 1-25 : 11-13

Notoliparis antonbruuni new species

(Fig. 4)

Holotype: SIO 65-610, female,>117 mm SL, “Anton Bruun” Sta. (524B)3, ca. 12° S, 79° W, ca. 120 n.mi.W of Callao, Peru, 24 Nov. 1965, 6150 m. Poor condition, in three pieces.

Diagnosis. A Notoliparis with 29 pectoral-fin rays, 59 or more vertebrae, eye 1.8 % SL or more, and anus less than disk diameter distant from disk.

Description. Counts: V>59 (12+?47), P 29 (22+2+5), C 9 (4/4+1). Ratios: eye ³1.8 SL, disk-anus in disk> 1.3, disk in anus-A <1.8.

Head badly damaged, unmeasurable. Eye tiny, lens almost as large as entire eyeball. Nostrils unknown. Premaxillary teeth long, slender, sharp, slightly recurved canines in about 28 oblique rows of up to 5 or 6 teeth each, forming a narrow band, up to 4 teeth wide at symphysis but almost uniserial posteriorly. Mandibular teeth similar in shape and arrangement, but in about 23 rows of up to 4 teeth each. Innermost teeth largest, outermost moderately large. Cephalic canals and pores and gill openings missing.

Pectoral fin rays probably 29 (22+2+5), wider in notch but not clearly distinct from upper and lower lobes; rudimentary rays absent. Left pectoral girdle badly damaged, removed for clearing and staining; scapula broad, coracoid with well-developed shaft. Four large, round, poorly calcified radials present (1+1+1+1), dorsalmost largest, notches and foramina absent. Body relatively deep. Pleural ribs absent. Disk well-developed, only its skeleton remaining; estimated diameter without margin 1.3 distance from it to anus. Abdominal vertebrae lacking elongate parapophyses and haemal spines; first caudal vertebra with complete haemal spine. Pleural ribs absent. Hypurals completely fused, (presumed) lower half better developed than the upper. Peritoneum pale, stomach dusky.

The specimen has ripe eggs of about 7.5 mm diameter.

Distribution. Known only from the single specimen taken at hadal depths off Callao, Peru.

Etymology. Named after the R/V “Anton Bruun,” which collected the specimens of the new taxa described in this paper and whose cruises added significantly to knowledge of the South American deep-sea fish fauna.

Remarks. Although this specimen clearly represents a previously unknown species, the extensive damage to it means it is impossible to determine its genus with certainty; it could be in Careproctus , Notoliparis , or Pseudoliparis . The specimen is so fragile that during clearing and staining, the pectoral girdle disintegrated, but not before the positions of the radials could be determined; Fig. 4C shows the scapula, radials, and coracoid, in their correct (reconstructed) positions. In many respects it is similar to C. sandwichensis Andriashev and Stein 1998 from 5450 m in the South Sandwich Trench, but it is notably different in pectoral fin structure (two or three notch rays, widely separated, vs all rays equally spaced; all radials round vs “rounded squares”; dorsal radial (1) largest, others equal size vs 1 largest, gradually smaller ventrally), premaxillary tooth number and pattern (ca 28 vs. about 8 oblique rows), eye size (56 vs. 48 times in SL), caudal rays (9 rays, 1+4/ 4 vs. 11 1+5/3+2), and distance from anus to anal fin origin (ca. 9 vs. ca. 13 % SL). Both Notoliparis and Pseudoliparis are distinguished from other liparid genera particularly by the structure of the cephalic canals (presence of a coronal pores and blind canaliculi), but also in absence of pleural ribs, having rounded pectoral radials without notches or fenestrae, reduced eyes, and lack of pigmentation (Andriashev, 1975; Andriashev & Pitruk, 1993). The significant distinctions between the two are primarily differences in the structure of the cephalic canal and pore system (which unfortunately cannot be determined in this specimen). The new specimen fits all the other generic characters, notably pectoral girdle structure, extremely small eye, absence of pleural ribs, and number of caudal fin rays. Pseudoliparis species (two) are known only from trenches in the North Pacific, and those of Notoliparis (three) are known only from South Pacific trenches. Based on distribution, it seems most likely that this is a new species of the latter, and therefore it is included in that genus.

Notoliparis antonbruuni differs from the other three species of the genus in having large, well-developed radials gradually decreasing in size ventrally (vs small, size otherwise). In number of pectoral rays (29) it is similar to all (31, 31, and 32-33 rays respectively). In number of vertebrae (59) it is most similar to N. macquariensis (with 56-58; N. kurchatovi has 50, N. kermadecensis has 65) but is distinct in having the lowest radial smallest (vs. the third smallest), a smaller eye (55 or more vs. 40-43 times in SL), greater distance from anus to anal fin origin (about 8 vs. more than 10 times in SL), and other characters.

The liparids are one of the most diverse fish families with hadal representatives. Notoliparis antonbruuni increases the number of liparid species known from depths below 6000 m to four; the others are Pseudoliparis amblystomopsis (Andriashev 1955) , Notoliparis kermadecensis (Nielsen 1964) , and Pseudoliparis belyaevi Andriashev and Pitruk 1993 . Three more species are known between 5-6000 m ( Careproctus sandwichensis Andriashev & Stein 1998 , Notoliparis kurchatovi Andriashev 1975 , and Notoliparis macquariensis Andriashev 1978 ).

Although this specimen is in very poor condition (skinned, most of head missing, broken into three pieces), it is nevertheless distinct enough to distinguish from other species and is described herein because it is unlikely that any more individuals will be collected in the foreseeable future.