“Melinantipoda antarctica, new species

 

Records: 17:2 sta. 945 (1, TYPE); 17:3 sta. 948 (1);

 

18: 4 sta. 1127 (2); 18:11 sta. 1140 (2); 18: 13 sta. 1146 (1+)

 

Description: A large, ovigerous, complete specimen is considerably macerated because it was fixed in the tube; it measures 60 mm long without the 16 mm long oral tentacles, which are extended forward; half of the total length is thoracic; the body tapers posteriorly and is 5 to 6 mm wide in the thoracic region. The body consists of 17 thoracic and more than 15 abdominal segments; in one specimen the posterior end is tapering and abruptly inflated in the pygidial end; a preanal, asetigerous part of four or more segments lacks parapodia. The tube is long, limp, silt-covered, weakly lined, and tears easily in a longitudinal direction; greatest length is 116 mm and width 9 mm. A well preserved, incomplete specimen, from sta. 945, is selected as type; it measures 39+ mm long by 5 mm wide. A dorsal transverse membrane, with its margin produced into 14 serrations, crosses the fourth setigerous segment. A broad, collarlike flange, formed by the anterior edge of the first setigerous segment, partly conceals the ventral side of the peristomium. The oral membrane and long, longitudinally grooved tentacles are partly extendd; tentacles in the median part of the series are longest, and resemble the smaller ones in lateral position.

 

The first two setigers have minute, short, transverse rows of fine, ventral unini; the third and fourth setigers are similar, but each has in addition a small notosetal fascicle. The 13 more posterior setigers have large notosetal fascicles, and the last 12 rows of normal uncini. Thoracic notosetae are long, limbate, distally pointed, and smooth along the edges. Uncini are avicular, in single rowsl each has three teeth in a row along the cutting edge. Abdominal parapodia have plain uncinigerous tori without modifications.

 

Branchiae are so inserted that the most anterior pair is nearly in contact at the base; the second pair is widest apart, the third pair approaches medially, and the fourth pair is slightly more dorsal; together they form a compact series across the middorsum.

 

Distribution: This has been taken only off Peter I Island, and in the Mid-Pacific Basin, in 3848-4795 in.”
(Hartman, 1967)

Holotype for Melinantipoda antarctica Hartman, 1967
Catalog Number: USNM 55563
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Preparation: Alcohol (Ethanol)
Collector(s): University of Southern California
Year Collected: 1964
Locality: Ellsworth Land, Peter I Island, Antarctica, Antarctic Ocean
Depth (m): 3020 to 3020
Vessel: Eltanin R/V

Depth range based on 12 specimens in 1 taxon.
Water temperature and chemistry ranges based on 12 samples.

Environmental ranges
  Depth range (m): 3111 - 4792
  Temperature range (°C): -0.106 - 0.412
  Nitrate (umol/L): 31.805 - 33.668
  Salinity (PPS): 34.658 - 34.708
  Oxygen (ml/l): 4.959 - 5.353
  Phosphate (umol/l): 2.198 - 2.308
  Silicate (umol/l): 117.574 - 144.882

Graphical representation

Depth range (m): 3111 - 4792

Temperature range (°C): -0.106 - 0.412

Nitrate (umol/L): 31.805 - 33.668

Salinity (PPS): 34.658 - 34.708

Oxygen (ml/l): 4.959 - 5.353

Phosphate (umol/l): 2.198 - 2.308

Silicate (umol/l): 117.574 - 144.882
 
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