Doloria (Dolorietta)

Chavtur, Vladimir G., Brandão, Simone N. & Bashmanov, Alexander G., 2012, New subgenus and new species of marine benthic ostracods of genus Doloria (Ostracoda; Myodocopina) from the Southern Ocean, Zootaxa 3356, pp. 1-46 : 38-45

Doloria (Dolorietta) sp. nov. 2

( Figs 23–28 )

Material. ZMH K- 41913, ANDEEP I, PS 61, ANT XIX/3, St. 41–3, 59º21.69´S – 60º5.18´W to 59º22.55´S – 60º4.01´W, depth 2333–2359 m, 27 January 2002: 1 juvenile female (carapace length 3.36 mm); valves (right valve deformed) in micropaleontological slide; one limb of antennula, anterior body, upper lip, Bellonci organ, lateral eyes and medial eye in alcohol; remaining appendages mounted on permanent slide.

Diagnosis. Juvenile female. Carapace: length 3.36 mm. Infold posterior to rostrum with about 9 short, simple bristles, and 2 long, double bristles forming a vertical row; 1 long, double bristle placed posterior this row. Antennula: sensory bristle of 5th segment with ten filaments, 7 proximal and 3 distal of which two are long, and the most distal is short. Mandibula: dorsal margin of basale with 1 proximal bristle; dorsal margin of 2nd endopodite segment with 7 long, 2 medium-sized and 5 short bristles. Fifth limb: main tooth of 1st exopodite segment with 5 pectinate teeth and proximally a broad, distally rounded process; 4th and 5th exopodite segments separated by a suture, with 4 and 2 bristles, respectively. Sixth limb: epipodial appendage with 3–4 bristles. Seventh limb: tip with comb of 13 teeth; limb with 23–24 distal and 34–39 proximal bristles. Furca : each lamella with 9 claws, 4th claw slightly more slender than 5th claw on right lamella only. Lateral eyes: absent. Bellonci organ: large and cylindrical, slightly pointed at tip. Anterior body: surface straight.

Description of juvenile female. Carapace ( Figs 23 , 24 , 25A). Length 3.36 mm. Greatest height about 70% of maximum length ( Figs 23 A, 25A). Carapace oval, with rounded, posterior margin, and fairly deep incisur with overhanging rostrum ( Figs 23 A, 25A). Antero-ventral margin angular. Surface smooth. Infold broad anteriorly, narrow ventrally and slightly broader posteriorly ( Fig. 24 A). Infold posterior to rostrum with about 9 short, simple bristles together with 2 long, double bristles forming vertical row; 1 long, double bristle posterior to this row ( Fig. 23 B). Infold around margin of incisor bare. Antero-ventral and ventral infolds with numerous double bristles (1 long and 1 short) and without pores ( Fig. 23 C, D). Inner margin of posterior infold with raised list of tiny bristles and a dense row with pores.

Antennula (Fig. 25B, D). 1st and 2nd segments bare (Fig. 25B). 3rd segment with 2 bristles, ventral bristle subterminal, dorsal bristle proximal. 4th segment with 2 distal bristles, ventral bristle extending beyond the distal margin of 5th segment; dorsal bristle slightly shorter than 5th segment (Fig. 25B). Sensory bristle of 5th segment with 7 proximal filaments plus distally 3 more long filaments, and most distally another short filament. Medial bristle of 6th segment slightly shorter than 5th segment. Seventh segment: a-bristle broken; b-bristle with 2 short, proximal and 2 long, distal, pectinate marginal filaments; c-bristle with 8 long, proximal, pectinate filaments, and 1 short, distal, bare, marginal filament. 8th segment (Fig. 25D): d- and e-bristles bare, slightly longer than b-bristle; g-bristle longer than f-bristle, both with 8 long, proximal, pectinate filaments, and 1 short, distal, bare filament.

Antenna (Fig. 25E–J). Protopodite slightly shorter than exopodite, and with a single relatively long, medial bristle. Endopodite 3-segmented (Fig. 25I, J): 1st segment with 2 short and 1 long proximal bristles, and 1 long, distal bristle about 2/3 length of 2nd segment. 2nd segment bare. 3rd segment with long, terminal filament fairly longer than endopodite. Exopodite (Fig. 25E–G): basal spines present on segments 3 to 9 (Fig. 25E–G); spines on 3rd to 8th segments distally conical, spine on 9th segment bifurcate or with small marginal teeth; spines on distal segments longer than those on proximal segments. Spine on 9th segment about 85% length of 8th segment. Bristle on 2nd segment (Fig. 25H) reaching the distal margin of 9th segment, with about 16 teeth on ventral margin; dorsal margin bare. Natatory setules present on bristles on segments 3 to 8. 9th segment with 4 bristles, all with natatory setules, dorsal bristle shorter than others.

FIGURE 25. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K-41913). A, left valve; B, anterior of body showing medial eye, Bellonci organ, antennula and upper lip; C, Bellonci organ; D, distal part of 1st antenna. Antenna: E, exopodite; F and G, distal part of exopodite; H, bristle of 2nd exopodite segment; I and J, endopodite. Mandibula: K, part of 2nd endopodite segment; L, distal part of coxale endite. Maxillula: M, cutting edge on 1st endopodite segment.

FIGURE 26. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K-41913). Mandibula: A, whole limb; B, part of 2nd endopodite segment; C, exopodite and parts of endopodite and basale; D, distal part; E, margin of basale; F, coxale endite. Sixth limb: G, epipodite.

FIGURE 27. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K-41913). Maxillula: A, whole limb (without distal part); B, distal part. Fifth limb: C, main tooth on 1st exopodite segment; D, bristle near main tooth on 1st exopodite segment; E, distal part of exopodite; F, anterior process of protopodite.

Mandibula (Figs 25K, L; 26A–E). Coxale endite triangular, strongly spinous, at its tip with 2 stout spines (one bare the other with secondary stout, marginal teeth) with an intermediate minute peg (Figs 25L, 26F). A short bristle with blunt tip present at base of endite (Fig. 25L). Basale (Fig. 26E): dorsal margin with a short, proximal bristle, a long, distal bristle, and 2 long, terminal bristles (Fig. 25A). Ventral margin with 3 medium-length and 1 short a-bristles; a long and a short b-bristles; a medium-sized c-bristle and a long d-bristle. Exopodite longer than 1st endopodite segment, with a hirsute disto-dorsal margin and pointed tip and a medium-length and a long distal bristle (Fig. 26C). Endopodite: ventral margin of 1st segment with 4 distal bristles (1 short, 1 medium-sized and 2 long); dorsal margin bare. Ventral margin of 2nd segment with a few distal marginal spines, and 1 + 1 + 2 slender bristles. Dorsal margin with 2 medium-length and 5 short bristles; distal segment with 2 long and 1 shorter claw-like bristles, and 4 simple bristles (ventral bristle short) (Figs 25K, 26B, D).

Maxillula (Figs 25M; 27A, B). 1st, 2nd and 3rd endites with 9, 6 and 6 bristles, respectively (Fig. 27A). Coxale with 1 stout, plumose bristle. Basale with 1 long and 2 medium-length bristles. Endopodite: 1st segment with 2 long α-bristles, 3 β-bristles (largest bristle with two rows teeth, the medium-length bristle with one row of teeth, the shortest bristle being bare; cutting edge with rounded small teeth (Fig. 25M). 2nd segment with 4 simple a-bristles; 3 strongly pectinate b-bristles; 3 c-bristles (2 pectinate and 1 simple), and 3 stout, bare claw-like d-bristles (Fig. 27B). Exopodite with 2 long (1 plumose, 1 usual), terminal and 1 shorter, marginal bristles (Fig. 27A).

Fifth limb (Fig. 27C–F). Epipodial appendage deformed. Protopodite with straight thick, short, sclerotized anterior process on distal margin (Fig. 27F). Exopodite: main tooth consists of 5 pectinate teeth (Fig. 27C); proximal, broad process with rounded tip and 1 spinous bristle (with about 4 middle, slender teeth on both limbs) (Fig. 27D). Inner lobe of 3rd segment with 3 bristles (1 short, plumose and 2 long, simple bristles). Outer lobe with 2 long, plumose bristles. 4th segment with 4 bare bristles (Fig. 27E). Conspicuous suture between 4th and 5th segments, 5th segment with 2 bristles (1 plumose). 3rd to 5th segments hirsute (Fig. 27E).

Sixth limb (Figs 26G; 28A, B). Epipodial appendage with 3–4 bare bristles and proximal to these bristles, a conspicuous protuberance (Fig. 26G). 1st endite with 2 long, distal and 2 short, medial plumose setae ( Fig. 28 B). 2nd endite with 2 long and one minute distal bristles, and two more relatively long, medial bristles ( Fig. 28 B). 3rd endite with 4 long, plumose, 1 short, bare and 1 short, spinous bristles ( Fig. 28 B). 4th endite with 5 long and 2 short bristles (4 long and 1 short, plumose, 1 bare) ( Fig. 28 B). Distal segment with 14 long, plumose bristles and 7 shorter spinous bristles ( Fig. 28 A).

Seventh limb. Tip with comb of 13 elongated teeth with paired, middle marginal spines; middle tooth longer than others and recurved. Stout, crescent-shaped, bare tooth present opposite to comb. Limbs with 13 dorsal and 10–11 distal bristles with 1–4 bells, and 16 dorsal and 18–23 ventral bristles with 1–4 bells.

Furca ( Fig. 28 C, D). Each lamella with 9 claws ( Fig. 28 C, D). 2nd claw slightly stouter than 1st claw. Right lamella: 4th claw more slender than 5th claw ( Fig. 28 C). Left lamella: 4th claw larger than 5th claw ( Fig. 28 D).

Medial eye (Fig. 25B). Large, unpigmented.

Lateral eyes. Absent.

Bellocini organ (Fig. 25B, C). Large, cylindrical and slightly pointed at tip.

Upper lip (Fig. 25B). Lip consisting of unpaired anterior part with glandular pegs along margin, 2 pairs of short tusks ventrally, and unpaired hirsute posterior lobe; anterior and posterior pairs of tusks with any glandular pegs.

Anterior body (Fig. 25B). Straight with medium-sized, rounded, anterior process.

Comparisons. Doloria (Dolorietta) sp. nov. 2 resembles D. (D.) levinsoni , but differs in (1) the type of double bristles on the antero-ventral and ventral infolds of the carapace; (2) the shape of proximal process on main tooth of fifth limb; (3) the Bellonci organ; and (4) the anterior body. Besides, D. (D.) sp. nov. 2 is close to D. (D.) sextafiliformis , but differs in (1) the bifurcated basal spine on the 9th exopodite segment of antenna; (2) the shape of the Bellonci organ; and (3) the anterior body (Table 3).

Distribution. Recent. Drake Passage, Scotia Sea, Atlantic Sector of the Southern Ocean. Deep bathyal (2333–2359 m).

Remarks. This new species is left in open nomenclature because of the lack of adult specimens.

Figures

FIGURE 23. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K- 41913). Carapace: A, left valve in lateral view; B, rostrum, internal view; C, antero-ventral margin, internal view; D, anterior part, internal view.

FIGURE 24. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K- 41913). Carapace: A, posterior part; B, posterior list; C, bristle on posterior list; D, pore at area between posterior list and posterior margin.

FIGURE 28. Doloria (Dolorietta) sp. nov. 2 (juvenile female: ZMH K- 41913). Sixth limb: A, whole limb; B, endites. Furca: C and D, right and left lamellae.