Macrourus caml, Mcmillan, Peter, Iwamoto, Tomio, Stewart, Andrew & Smith, Peter J, 2012

Mcmillan, Peter, Iwamoto, Tomio, Stewart, Andrew & Smith, Peter J, 2012, A new species of grenadier, genus Macrourus (Teleostei, Gadiformes, Macrouridae) from the southern hemisphere and a revision of the genus, Zootaxa 3165, pp. 1-24 : 4-9

Macrourus caml sp. nov.

Caml grenadier

Macrourus whitsoni (in part not Regan 1913): Trunov & Konstantinov, 1989: 54–65 (97 specimens, description, compared with M. carinatus , in Russian, English summary). Marriott et al., 2003: 39–41 (364 specimens, Ross Dependency).

Diagnosis. Ventral surface of the head mostly scaled, except for scaleless areas anterior to the mouth and on the anterior half of the lower jaw. Pelvic fin with 8 rays, rarely 7 or 9. Lower jaw with 2–3 rows of small pointed uniform-sized teeth reducing to a single row posteriorly. Upper jaw with 4–5 rows of small, uniform-sized teeth. Body scales small, 30–40 in a diagonal row from anal fin origin to lateral line. Pyloric caeca 20–37.

Specimens examined. Holotype. NMNZ P.043633 (123 mm HL, 589+ mm TL), Ross Sea slope, Antarctica, 72º 21' S, 175º 33' E, 945–952 m, RV Tangaroa , IPY/ CAML TAN 0802/121, bottom trawl, 21 Feb 2008.

Paratypes (33). AMS I.45750-001 ex NMNZ P.037602 (102 mm HL, 456 mm TL), Ross Sea slope, 73º 56' S, 176º 53' W, 838–922 m, FV Janas, OBS 1302/126, bottom longline, 21 Feb 2000; BMNH 2011.8.1.1 ex NMNZ P. 9372 (118 mm HL, 577 mm TL), Ross Sea slope, 73º 15' S, 177º 18' W, 940–1211 m, FV Janas, OBS 1181/027, bottom longline, 19 Jan 1999; CAS 233433 ex NMNZ P.043997 (102 mm HL, 479 mm TL), Ross Sea slope, 73º 15' S, 178º 44' E, 760–770 m, RV Tangaroa , IPY/ CAML TAN 0802/106, bottom trawl, 19 Feb 2008; CSIRO H 7251-01 ex NMNZ P.043592 (77 mm HL, 359 mm TL), Ross Sea slope, 73º 15' S, 178º 44' E, 760–770 m, RV Tangaroa , IPY/ CAML TAN 0802/106, bottom trawl, 19 Feb 2008; MNHN: 2011-0280 ex NMNZ P. 040371 (62 mm HL, 279 mm TL), Balleny Islands, 66º 33' S, 163º 1' E, 550–574 m, RV Tangaroa , TAN 0402/249, bottom trawl, 0 5 Mar 2004; NMNZ P.036091 (168 mm HL, 767 mm TL), Ross Sea slope, 72º 3' S, 173º 35' E, 885–1038 m, FV Janas, OBS 1181/109, bottom longline, 17 Feb 1999; NMNZ P.036104 (119 mm HL, 580 mm TL), Ross Sea slope, 73º 15' S, 177º 18' W, 940–1211 m, FV Janas, OBS 1181/027, bottom longline, 19 Jan 1999; NMNZ P.036142 (104 mm HL, 380 mm TL), NMNZ P.036173 (115 mm HL, 425 mm TL), Ross Sea slope, 73º 1' S, 176º 53' E, 863–919 m, FV San Aotea II, OBS 1180/004, bottom longline, 14 Jan 1999; NMNZ P.036174 (84 mm HL, 370 mm TL), Ross Sea slope, 71º 27' S, 178º 40' W, 1020–1111 m, FV San Aotea II, OBS 1180/103, bottom longline, 15 Feb 1999; NMNZ P.036988 (3, 99– 103 mm HL, 465–469 mm TL), South Georgia, 54º 0' S, 39º 0' W, 1300–2000 m, Apr 1997; NMNZ P.037599 (126 mm HL, 485 mm TL), Ross Sea slope, 74º 23' S, 176º 33' W, 896– 896 m, FV Janas, OBS 1302/144, bottom longline, 26 Feb 2000; NMNZ P.037602 (2, 103– 122 mm HL, 433–542 mm TL), Ross Sea slope, 73º 56' S, 176º 53' W, 838–922 m, FV Janas, OBS 1302/126, bottom longline, 21 Feb 2000; NMNZ P.037603 (99 mm HL, 439 mm TL), Ross Sea slope, 74º 16' S, 176º 53' W, 786–796 m, FV Janas, OBS 1302/139, bottom longline, 25 Feb 2000; NMNZ P.037762 (2, 114– 121 mm HL, 536–554 mm TL), Ross Sea slope, 69º 21' S, 178º 39' W, 425–1661 m, FV Janas, OBS 1429/122, bottom longline, 20 Feb 2001; NMNZ P.038635 (131 mm HL, 533 mm TL), Scott Island seamounts, 68º 2' S, 179º 7' W, 1010–1156 m, FV San Aotea II, OBS 1595B/138, bottom longline, 18 Apr 2002; NMNZ P.038793 (184 mm HL, 890 mm TL), Ross Sea slope, 71º 15' S, 176º 36' E, 1440 m, FV San Aotea II, OBS 1725/041, bottom longline, 22 Jan 2003; NMNZ P. 040634 (2, 102– 112 mm HL, 445–461 mm TL), Ross Sea slope, 71º 31' S, 178º 45' W, 1168–1251 m, FV Gudni Olafsson, OBS 1843/075, bottom longline, 10 Feb 2004; NMNZ P. 041446 (132 mm HL, 625 mm TL), Cosmonaut Sea, 66º 19' S, 33º 14' E, 1317–1334 m, FV Janas, OBS 2068/033, bottom longline, 26 Mar 2005; NMNZ P. 042222 (147 mm HL, 722 mm TL), Pacific-Antarctic Ridge, 66º 30' S, 176º 23' W, 1660–2080 m, FV Avro Chieftain, OBS 2186/006, bottom longline, 22 Dec 2005; NMNZ P. 042353 (128 mm HL, 618 mm TL), Ross Sea slope, 72º 39' S, 179º 35' W, 762–793 m, FV Sonrisa, OBS 1311/001, bottom longline, 30 Jan 2000; NMNZ P. 042587 (123 mm HL, 527 mm TL), South Georgia, 54º 39' S, 39º 3' W, 1260 m ,, FV San Aspiring, OBS 2234/123, bottom longline, 0 6 Jul 2006; NMNZ P. 042591 (147 mm HL, 720 mm TL), South Georgia, 53º 13' S, 42º 7' W, 1280 m ,, FV San Aspiring, OBS 2234/236, bottom longline, 27 Aug 2006; NMNZ P.043591 (87 mm HL, 319 mm TL); NMNZ P.043683, (123 mm HL, 598 mm TL), Ross Sea slope, 71º 56' S, 173º 18' E, 1431–1658 m, RV Tangaroa , IPY/ CAML TAN 0802/144, bottom trawl, 23 Feb 2008; NMNZ P.043997 (122 mm HL, 573 mm TL), Ross Sea slope, 73º 15' S, 178º 44' E, 760–770 m, RV Tangaroa , IPY/ CAML TAN 0802/106, bottom trawl, 19 Feb 2008; NMNZ P.045643 (41 mm HL, 184 mm TL), Scott Island seamounts, 68º 7' S, 179º 15' W, 855–879 m, RV Tangaroa , IPY/ CAML TAN 0802/211, bottom trawl, 0 3 Mar 2008; USNM 402714 ex NMNZ P. 040102 (68 mm HL, 321 mm TL), Ross Sea slope, 71º 30' S, 171º 48' E, 540–549 m, RV Tangaroa , TAN 0402/172, bottom trawl, 27 Feb 2004.

Non-type specimens (28). NMNZ P.038623 (115 mm HL, 405 mm TL), Ross Sea slope, 71º 48' S, 177º 26' W, 757–784 m, FV Janas, OBS 1593A/034, bottom longline, 26 Jan 2002; NMNZ P. 040263 (10, 38– 50 mm HL, 174–236 mm TL), Balleny Islands, 67º 15' S, 164º 51' E, 348–353 m, RV Tangaroa , TAN 0402/218, bottom trawl, 0 3 Mar 2004; NMNZ P. 040322 (7, 26– 59 mm HL, 132–274 mm TL), Balleny Islands, 66º 33' S, 163º 1' E, 550– 574 m, RV Tangaroa , TAN 0402/249, bottom trawl, 0 5 Mar 2004; NMNZ P. 040370 (80 mm HL, 360 mm TL), Balleny Islands, 66º 41' S, 162º 46' E, 377–383 m, RV Tangaroa , TAN 0402/246, bottom trawl, 0 5 Mar 2004; NMNZ P.043590 (6, 20– 63 mm HL, 108–301 mm TL), Ross Sea slope, 73º 15' S, 178º 44' E, 760–770 m, RV Tangaroa , IPY/ CAML TAN 0802/106, bottom trawl, 19 Feb 2008; NMNZ P.043883 (38 mm HL, 170 mm TL), Admiralty seamount, 66º 59' S, 170º 51' E, 445–455 m, RV Tangaroa , IPY/ CAML TAN 0802/265, bottom trawl, 10 Mar 2008; NMNZ P.043890 (2, 21– 35 mm HL, 83–160 mm TL), Admiralty seamount, 67º 7' S, 170º 56' E, 543–545 m, RV Tangaroa , IPY/ CAML TAN 0802/279, epibenthic sled, 11 Mar 2008.

Counts and measurements ( Tables 1 –2).

Description (Figures 2–4, Tables 1 –2). Head large, length 3.2 to 5.5 into total length. Moderately strong scutes on head ridges, armed with short spinules. Blunt, slightly rounded snout, length less than orbit diameter, tipped with a prominent scute. Upper jaw about same length as orbit diameter, posterior end of premaxilla below or just behind mid-orbit. Chin barbel about one-third of orbit diameter.

Teeth in both jaws small, pointed, may be slightly curved inwards. Upper jaw teeth in 3–5 rows with outer teeth not noticeably enlarged relative to those of inner rows. Lower jaw closely spaced with 2–4 rows at tip, reducing to 1–2 rows posteriorly, outer teeth not noticeably enlarged.

Origin of pelvic fin slightly in advance of pectoral fin, and both slightly in advance of origin of first dorsal fin. First dorsal height and pectoral fin length relatively large compared to others in genus.

Body scales small, deciduous. Those between lateral line and first dorsal fin base with a central long row of enlarged spinules and 3–4 short rows of small spinules on each side. Lower body scales mostly lack a central row of spinules. Dorsal head covered with adherent scales, except for scaleless area around nostrils that extends dorsally to nasal ridge and ventrally to suborbital ridge. Ventral surface of snout anterior to mouth scaleless. Numerous rows of small flat scales lacking spinules at posterior end of ventral surface of head, extending forward to about level with anterior end of orbit and reducing to 1–2 rows anteriorly. Small scales on rear one-third to half of lower jaw in 1–3 rows.

Fresh colour of head and body medium to dark brownish or blackish with smaller specimens paler. Sides of head and trunk of large specimens may have greenish iridescence. Bluish abdominal area below about upper edge of pectoral fin base in smaller individuals, but not obvious in larger ones. Lining of mouth and gill cavity greyishblack. Lips brownish. Ventral snout dark brownish with numerous pale pore openings. Fins brownish in smaller and blackish in larger specimens. Preserved specimens brownish or blackish overall.

Size. To at least 890 mm TL and about 4.4 kg.

Distribution ( Figure 5 A). Probably widespread in the Southern Ocean including the Ross Sea, Balleny and Scott Islands slope, Cosmonaut Sea (33 E), south of South Georgia (54 S), at 350–2080 m.

Etymology. Named for the Census of Antarctic Marine Life ( CAML , pronounced ‘camel’) carried out in International Polar Year (2008). Treated as a noun in apposition to the genus name (International Commission on Zoological Nomenclature, 1999).

Comparisons and remarks (Table 3). Previously confused with Macrourus whitsoni . The first author participated in two biodiversity surveys of the Ross Sea (2004 & 2008) but did not recognise the presence of the two species of Macrourus during initial sorting of catches. DNA analysis (C01) of tissue samples collected during the 2008 IPY surveys indicated four clades among the Southern Ocean specimens: M. carinatus , M. holotrachys , M. whitsoni , and an undescribed species (Fig 2, Smith et al. 2011). Meristic and morphometric examination of Te Papa collection specimens resulted in the conclusion that there were two sympatric species. M. whitsoni has more pelvic fin rays (9, rarely 10), usually a single row (may be 2 rows at tip) of long, spaced, teeth in the lower jaw, upper jaw with 3–5 rows of teeth with outer row slightly enlarged relative to inner rows, 15–26 pyloric caeca. M. carinatus has larger body scales with 19–25 in a diagonal row from anal fin origin to lateral line, fewer pyloric caeca 13–20, and upper jaw has an outer row of slightly enlarged teeth. M. berglax from the northern hemisphere and M. holotrachys from the southern hemisphere usually have an almost scaleless ventral surface of the head.

Trunov and Konstantinov (1989) reported numerous specimens of what they identified as Macrourus whitsoni from the Southern Ocean. But it is very likely that their material included both M. caml and M. whitsoni because their reported counts of pelvic fin rays, pyloric caeca, and scales from anal fin origin to lateral line mostly straddle the counts made by us for the two separate species ( Table 4 ).

Macrourus caml appears to be abundant in the Ross Sea region and there are numerous specimens of the new species in the Te Papa collection. Many were collected by observers from bottom longline vessels fishing for Antarctic and Patagonian toothfish. Both M. caml and M. whitsoni appear to readily take baited hooks and are a substantial part of the fishery bycatch ( Hanchet et al. 2008). Both species have been taken on the same bottom longline set and appear to occupy similar depths although M. whitsoni appears to extend to slightly greater depths. The slightly smaller and more subterminal mouth of M. caml suggests a more benthic diet compared to M. whitsoni which has a slightly larger gape, more terminal mouth and longer teeth. The method of capture (bottom longline and trawl) usually results in the expansion of the gas (swim) bladder and an everted stomach, making feeding study difficult.

Figures

FIGURE 5. Distribution maps for southern hemisphere species of Macrourus based only on specimens examined in this study. (A) M. caml sp. nov.; (B) M. carinatus; (C) M. holotrachys; (D) M. whitsoni.