Leucon (Crymoleucon) antarcticus, Zimmer, 1907

Mühlenhardt-Siegel, Ute, 2011, New and known species of the family Leuconidae (Cumacea, Peracarida) from Antarctic deep-sea basins 3117, Zootaxa 3117 (1), pp. 1-68 : 11

L. (Crymoleucon) antarcticus Zimmer, 1907

Previous records. described for the ”Winterstation der Deutschen Südpolar Expedition“ (385 m); rediscovered in McMurdo Sound (Winterquartier of the “Discovery”, Calman 1907 a, 100 fathoms); Ross Sea ( Jones, 1971, 110– 752 m; Rehm et al., 2007, 196– 474 m); Weddell Sea ( Ledoyer, 1993, 182– 2037 m), off Chile ( Petrescu, 1994, 4323 m); Prydz Bay, several stations (unpublished data).

Diagnosis. Thorax longer than abdomen; pseudorostrum long; antennal notch obvious and broad, reaching considerably backwards beyond the anterior margin of the frontal lobe; middorsal crista serrulated, reaching with a short posterior interruption the hind margin of carapace; two teeth on each lateral side of the frontal lobe: one close to the margin and one on the posterior part; additional tooth on the posterior part of the pseudorostral lobe.

New records. ( Figures 5–7 )

Leucon (C.) with one or two teeth laterally at frontal lobe, long dorsomedian serration reaching the posterior margin of the carapace. Pseudorostrum of normal length; male with two pairs of pleopods; dorsomedian line serrate, reaching the hind margin of the carapace without a gap; in general similar to previously caught L. (C.) antarcticus , but the gap in the dorsomedian serration is missing. Peninsula: ANT XV #320: 6 specimens; W Weddell Sea: ANT XIX #133 : 6 specimens; ANDEEP III #133: 63 specimens; ANDEEP III #150: 2 specimens; ANDEEP III #151: 3 specimens; E Weddell Sea: ANT XV #107: 22 specimens; ANT XV #142: 16 specimens; ANT XV #145: 1 specimen; ANT XV #272: 8 specimens; ANDEEP III #74: 43 specimens; ANDEEP III #78: 12 specimens; ANDEEP III #81: 2 specimens; S Sandwich Trench: ANT XIX #141 : 2 specimens, ZMH K 42933 .

Morphometric measurements:

Antenna 1: relative length of peduncle articles 1 to 3: 31/42/27;

maxilliped 2: B/R ratio 0.8, relative length of articles I to D: 8/28/31/23/11;

maxilliped 3: B/R ratio 1.8, relative length of articles I to D: 9/21/32/21/18;

pereiopod 1: B/R ratio 0.8, relative length of articles I to D: 10/16/31/28/16;

pereiopod 2: B/R ratio 0.8, relative length of articles I to D: 7/21/32/16/24;

pereiopod 3: B/R ratio 2.2, relative length of articles I to D: 14/24/38/21/3;

pereiopod 4: B/R ratio 1.2, relative length of articles I to D: 22/19/35/16/8;

pereiopod 5: B/R ratio 0.8, relative length of articles I to D: 16/20/35/20/9.

Uropod measurements:

pleotelson length to width: 0.9;

pleotelson 0.7 times as long as uropod peduncle;

uropod endopod longer than exopod;

uropod endopod basal to distal article: 1.9.

Figures

FIGURE 5. Leucon (C.) antarcticus Zimmer, 1907, non-ovigerous female habitus, 3.5 mm long.

FIGURE 6. Leucon (C.) antarcticus Zimmer, 1907, A1: antenna 1, Mxp2: maxilliped 2, Mxp3: maxilliped 3, P1: pereiopod 1, P2: pereiopod 2; scale bars: 50 µm (A1, Mxp2) and 100 µm (Mxp3, P1, P2).

FIGURE 7. Leucon (C.) antarcticus Zimmer, 1907, P3: pereiopod 3, P4: pereiopod 4, P5: pereiopod 5, U: pleotelson and uropods; scale bars: 50 µm (P5) and 100 µm (P3, P4, U).