Eudorella flokkeri, Mühlenhardt-Siegel, 2011

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 : 57-59

Eudorella flokkeri sp. n.

( Figures 41–44 )

Material. Holotype non-ovigerous female, ZMH: K 42957 ; 9 February 1998.

Type locality. Antarctica, south-eastern Weddell Sea , 74° 32.20’ S 27° 13.80’ W, 2081 m depth, ANT XV, #134, Agassiz trawl .

Paratypes: Peninsula: ANDEEP III #154: 1 male (dissected), 1 manca; W Weddell Sea: ANDEEP III #121: 2 small subadult females, 1 manca; ANDEEP III #151: 1 female (dissected), 1 non-ovigerous female (damaged); E Weddell Sea: ANT XV # 134: 5 subadult male, 1 non-ovigerous female (dissected), 6 subadult females, 3 mancas; ANT XV # 142: 1 subadult female; ANT XV #272: 2 subadult males, 23 non-ovigerous females, 7 mancas; ANDEEP III #74: 1 subadult male, 4 subadult females, 6 mancas; ANDEEP III #78: 11 subadult males, 10 ovigerous females, 29 non-ovigerous females (1 dissected), 19 small subadult females, 28 mancas. ZMH: K 42958 .

Etymology. The new species is dedicated to my very best and dearest friend Flokker

Diagnosis. Antennal notch wide and shallow, not sinuate; uropod endopod’s terminal seta fused.

Description. Holotype, 5.9 mm long ( Fig. 41 ).

Carapace much shorter (0.6 times) than free thoracic segments, very short pseudorostral lobes directed dorsally; siphonal tube short; ocular lobe reduced; eyes missing. Antennal notch wide and shallow, with teeth formula: 5 up and 1 down on anterior margin of carapace above and in the antennal notch; anterolateral tooth not pronounced; anteroventral margin of carapace serrate. Integument with scaly structure visible in higher magnification. Five free thoracic segments visible, the first shortest. Pleon longer than carapace and free thoracic segments combined. Pleotelson 0.9 times as long as uropod peduncle; tips of anal valves visible from above.

Appendages: subadult male (paratype, ANDEEP III #154 ) .

Antenna 1 ( Fig. 43 , A 1 ): geniculate between article 2 and 3; relative length of peduncle articles 1 to 3: 20/40/ 40; article 3 with five setulate setae along inner margin, one simple and two plumose setae at outer distal corner; accessory flagellum with three teeth along inner margin, ¾ as long as basal article of main flagellum; main flagellum tri-articulated, with three long simple setae along inner margin of basal article, one long simple seta at middle and two simple and one hair-like one at terminal article; two aesthetascs, one inserting at penultimate, one at terminal article.

Maxilliped 2 ( Fig. 43 , Mxp2): B/R ratio 0.4, relative length of articles I to D: 10/24/31/22/13; basis and merus with setulate seta at inner distal corner; carpus with ten setulate setae along inner margin; propodus with nine simple setae along inner margin and one long setulate seta inserting in the outer proximal third; dactylus with two simple setae distally, terminal seta (unguis) longer than article.

Maxilliped 3 ( Fig. 43 , Mxp3): B/R ratio 1.0, relative length of articles I to D: 6/20/30/22/22; basis with seven setulate setae along inner margin, broadened distally, with one short and three long setulate setae; merus with one long setulate seta at outer distal corner and one short one at inner margin; carpus with six setulate setae along inner margin; propodus with three setulate setae at inner distal corner; dactylus with two simple setae subterminally and terminal strong seta slightly shorter than dactylus; exopod basal article serrate.

Pereiopod 1 ( Fig. 43 , P 1 ): B/R ratio 0.7, relative length of articles I to D: 8/16/27/31/18; basis with three short setulate and four short simple setae along inner margin, one long setulate seta at outer distal corner; ischium with small tooth and one hair-like seta at inner and one setulate seta at outer margin; merus with setulate seta at outer distal corner; carpus with three hair-like setae along inner margin, one strong and one hair-like seta at outer margin; propodus with fine simple setae along inner and outer margin, one stronger simple seta at inner proximal corner is broken, at distal inner margin one slightly longer setulate seta; dactylus with eight simple setae, the terminal one longer than dactylus; exopod present.

Pereiopod 2 ( Fig. 43 , P 2 ): B/R ratio 0.9, relative length of articles I to D: 0/26/38/12/24; basis damaged, with one simple and two setulate setae along inner margin; ischium fused to basis; merus with one long setulate and one small simple seta at inner distal corner, one strong simple seta at outer distal corner; carpus with one strong simple seta at outer distal corner; dactylus with nine simple setae along inner and terminal margin; exopod basis with

Pereiopod 3 ( Fig. 44 , P 3 ): B/R ratio 2.4, relative length of articles I to D: 16/27/27/23/7; basis with one simple and two hair-like setae; ischium with long setulate seta at inner distal corner; merus with one hair-like and one strong simple seta at distal inner corner, one strong simple seta at outer distal corner; carpus with two strong simple setae at outer distal corner, one of them broken; propodus with long simple seta at outer and inner distal corner, minute dactylus with long terminal seta; exopod present.

Pereiopod 4 ( Fig. 44 , P 4 ): B/R ratio 1.6, relative length of articles I to D: 22/22/28/24/4; basis with few fine setae, the distal one setulate; merus with one simple seta at inner corner and one setulate seta at outer distal corner; propodus with one long and one short simple seta; minute dactylus with long terminal seta and one hair-like seta; exopod present.

Pereiopod 5 ( Fig. 44 , P 5 ): B/R ratio 1.4, relative length of articles I to D: 15/28/33/20/4; basis with two simple setae; merus with two simple setae; carpus with one long and one short simple seta; propodus with one short simple seta; minute dactylus with short terminal seta.

Uropod ( Fig. 44 , U): Peduncle with four cuspidate setae along inner margin, one hair-like seta at outer margin; exopod shorter than endopod; endopod bi-articulated; basal article with nine cuspidate setae along inner margin, 3.2 times as long as terminal article which has four cuspidate setae along inner margin, terminal seta fused, subterminal seta moderately long (broken in paratype), one small seta distally at outer margin.

Remarks. The variation of the tooth formula created by Given (1961) gives a good description of the complicated armature of the anterolateral margin in the genus Eudorella . However, this armature is not constant within one species but is dependent on sex and age (size) of the specimens as shown by Mühlenhardt-Siegel (1996).

The variation of teeth formula in the new species of Eudorella is in females: holotype: 5 up 1 down, paratypes: 2 up 2 down, 2 up 0 down, 0 up 0 down, 5 up 1 down (E Weddell Sea); in males: 0 up 7 down, 3 up 5 down ( Figure 42 ). The new species of Eudorella is similar to E. gracilior Zimmer, 1907 regarding the shape of the carapace and the antennal notch. However, E. gracilior has the terminal seta of the uropod endopod articulated to the distal article and the new species has it fused. There are few species in this genus with fused endopodal terminal seta: E. difficilis Blake, 1929 (W Atlantic, 9–12 m), E. divae Mühlenhardt-Siegel, 2005 ( Angola Basin, 5389–5415 m), E. nana Sars, 1879 (Mediterranean, 37–300 m) and E. splendida Zimmer, 1907 ( Antarctica, 12–250 m). All these species have an antennal notch clearly differing from the one of the new species.

tooth.

Figures

FIGURE 1. Leucon (A.) polarsterni Ledoyer, 1993, subadult female habitus, 5.5 mm long.

FIGURE 2. Leucon (A.) polarsterni Ledoyer, 1993, A1: antenna 1, Mxp2: maxilliped 2, Mxp3: maxilliped 3, P1: pereiopod 1, P2: pereiopod 2; scale bars 100 µm (A1, Mxp2, Mxp3) and 200 µm (P1, P2).

FIGURE 3. Leucon (A.) polarsterni Ledoyer, 1993, P3: pereiopod 3, P4: pereiopod 4, P5: pereiopod 5, U: pleotelson and uropods; scale bars 100 µm (P3, P4, P5) and 200 µm (U).

FIGURE 4. Leucon (A.) polarsterni Ledoyer, 1993, SEM photos, habitus female (above left), carapace (above right, middle left), uropods (middle right), endopod’s terminal seta (below).

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

FIGURE 41. Eudorella flokkeri sp. n., habitus holotype, non-ovigerous female, scale bar: 0.5 mm.

FIGURE 42. Eudorella flokkeri sp. n., variability of the anterolateral margin of the carapace.

FIGURE 43. Eudorella flokkeri sp. n., A1: antenna 1, Mxp2: maxilliped 2, Mxp3: maxilliped 3, P1: pereiopod 1, P2: pereiopod 2 (basis damaged); scale bars: 100 µm (A1, Mxp2, Mxp3) and 200 µm (P1, P2).

FIGURE 44. Eudorella flokkeri sp. n., P3: pereiopod 3, P4: pereiopod 4, P5: pereiopod 5, U: pleotelson and right uropod; scale bars: 50 µm (P5) and 100 µm (P3, P4, U).