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 : 30-38

Doloria (Dolorietta) sp. nov. 1

( Figs 18 –22, Tab. 4)

Material. ZMH K- 41912, ANDEEP III, PS 67, ANT XXII/3, St. 150–5, 61º48.61´S – 47º28.64´W to 61º48.96´S – 47º28.34´W, depth 2045–2150 m, 20 March 2005: 1 juvenile male (carapace length 3.47 mm); valves on micropaleontological slide; one limb of antennula, anterior body, upper lip, Bellonci organ, lateral eyes and medial eye in alcohol, remaining appendages mounted on slide.

Diagnosis. Juvenile male. Carapace: length 3.47 mm. Infold of rostrum with 2 vertical rows of bristles (anterior row with 3 short bristles, posterior row with 8 short and 5 long bristles). Antennula: sensory bristle of 5th segment with 7 long, proximal bare filaments; 3 slightly shorter, distal, bare filaments; and bifurcate tip. Mandibula: dorsal margin of basale with 1 proximal bristle; dorsal margin of 2nd endopodite segment with 5 long, 3 mediumsized and 8 short bristles on right limb, and 6 long, 3 medium-sized and 7 short bristles on left limb. Fifth limb: main tooth of 1st exopodite segment with 5 pectinate teeth, and proximal process relatively narrowly pointed at tip. 4th and 5th exopodite segments fused (i.e. no suture), 4th exopodite segment with 4 bristles. 5th exopodite segment with 2 bristles. Sixth limb: epipodial appendage with 4 bristles. Seventh limb: tip with comb of 15 teeth; limb with 21 distal and 36 proximal bristles. Furca : each lamella with 10 claws, 4th claw slightly more slender than 5th claw. Lateral eyes: large with about 21 divided ommatidia. Bellonci organ: slightly decreasing in thickness distally; distal part separated by suture and with nipple-like process at tip. Anterior body: surface straight.

Description of juvenile male. Carapace ( Figs 18 , 19A, B). Length 3.47 mm. Greatest height about 75% of maximum length ( Figs 18 A, 19A, B). Carapace oval with rounded posterior margin, and fairly deep incisur with overhanging rostrum; antero-ventral margin angular; surface smooth ( Fig. 18 A). Infold broad anteriorly ( Fig. 18 D), narrow ventrally and slightly broader posteriorly. Infold of rostrum ( Fig. 18 B, C, F) with 2 vertical rows of bristles (anterior row with 3 short bristles, posterior row with 13 (8 short, 5 long) bristles), 1 long bristle and some pores placed posterior to these rows. Two short bristles present around inner margin of incisor; antero-ventral ( Fig. 18 D) and ventral infolds with numerous double?paired bristles (1 long and 1 short) and some minute spine-like bristles.

Antennula (Figs 19C, F–H; 20A). 1st segment bare (Fig. 19C, F). 2nd segment with numerous clusters of minute spines along dorsal and ventral margins. 3rd segment with 2 bristles, ventral bristle sub-terminal, dorsal bristle proximal. 4th segment with 2 distal bristles, ventral bristle reaching end of 5th segment, dorsal bristle not reaching 5th segment. Sensory bristle of 5th segment (Fig. 19G) has a bifurcate tip and carries 7 long, bare filaments proximally and 3 slightly shorter, bare filaments distally. Medial bristle of 6th segment about as long as 5th segment. 7th segment: a-bristle bare and about twice as long as medial bristle on 6th segment; b-bristle with 3 proximal pectinate (with 6–7 teeth) filaments, and 2 distal, bare filaments; c-bristle with proximally 8 long, pectinate filaments, and distally a single short, bare, marginal filament (Fig. 19H). 8th segment: d- and e-bristles bare, longer than b-bristle; g-bristle longer than f-bristle, both with 8 long proximal, pectinate filaments and 1 short, distal, bare filament (Fig. 20A).

Antenna (Fig. 19I, J, 20B). Protopodite barely longer than exopodite and with relatively a short medial bristle. Endopodite 3-segmented (Fig. 19J): 1st segment proximally with 2 short and 1 long bristles and a single long distal bristle. 2nd segment with 2 short, dorsal sub-terminal bristles. 3rd segment reduced, with a single long medial filament ventrally (broken on both limbs) and 2 short bristles anteriorly. Exopodite (Fig. 20B): basal spines present on segments 3 to 9 (all spines distally conical); spines on distal segments longer than those on proximal segments. Spine on 9th segment about 80% length of 8th segment. Bristle of 2nd segment almost reaching 9th segment, with about 11 teeth along ventral margin, dorsal margin bare (Fig. 19I). Natatory setules present on bristles on segments 3 to 8. 9th segment with 4 bristles, all with natatory setules, dorsal bristle shortest.

Mandibula (Figs 20C–G, 21A–D). Coxale endite strongly spinous (Fig. 21D), with 2 stout spines at tip (both with additional stout, marginal teeth) and minute tubercle between them; short bristle (proximally thick and distally spine-like) present at base of endite (Fig. 21A). Basale (Fig. 20F, G, 21A): dorsal margin with 1 short, proximal bristle; 1 long, distal bristle and 2 long, terminal bristles. Ventral margin (Fig. 20F, 21A) with 3 medium-sized and 1 short (with 2 basal teeth, proximally thick and distally spine-like) a-bristles; 2 b-bristles (1 short, 1 long); 1 medium-sized c-bristle; and 1 long d-bristle. Exopodite reaching just beyond distal margin of 1st endopodite segment (Fig. 20G, 21A); with pointed tip, disto-dorsal margin hirsute, with 1 medium-length and 1 long bristle. Endopodite: ventral margin of 1st segment with distally 1 short, 1 medium-length and 2 long bristles (Fig. 20G); dorsal margin bare (Fig. 21A). Ventral margin of 2nd segment (Fig. 20C–E, 21B) with 3 groups of slender bristles (1 + 1 + 2 on right limb, and 1 + 1 + 1 on left) (Fig. 21A). Dorsal margin with 5 long, 3 medium-sized and 8 short bristles on right limb, and with 6 long, 3 medium-sized and 7 short bristles on left limb (Fig. 21B). Distal segment with 2 long and 1 shorter claw-like bristles, and 4 simple bristles (1 short, ventral and 3 long) (Fig. 20D, 21C). Ventral margin with 1–2 long, claw-like bristles with 3 long, proximal spines.

FIGURE 19. Doloria (Dolorietta) sp. nov. 1 (juvenile male: ZMH K-41912). Carapace: A, right valve, internal view; B, left valve in lateral view. C, anterior of body showing medial eye, Bellonci organ, antennula and upper lip. D, Bellonci organ. E, lateral eye. Antennula: F, whole limb (distal bristles not shown); G, distal part of bristle on 5th endopodite segment; H, distal part of c-, f- and g-bristles. Antenna: I, bristle on 2nd exopodite segment; J, endopodite.

FIGURE 20. Doloria (Dolorietta) sp. nov. 1 (juvenile male: ZMH K-41912). A, distal part of antennula; B, exopodite of antenna. Mandibula: C, 2nd endopodite segment; D, distal part of right limb (one claw broken); E, disto-ventral bristles on 2nd endopodite segment of left limb; F, ventral margin of basale; G, exopodite and parts of basale and endopodite. Maxillula: H, whole limb (bristles on endites and 2nd endopodite segment not shown); I, cutting edge.

FIGURE 21. Doloria (Dolorietta) sp. nov. 1 (juvenile male: ZMH K-41912). Mandibula: A, whole limb; B, 2nd endopodite segment; C, distal part; D, coxale endite and part of basale. Fifth limb: E and F, anterior process of protopodite; G, main tooth of 1st exopodite segment. H, distal part of seventh limb. I, 1st claw of furca .

FIGURE 22. Doloria (Dolorietta) sp. nov. 1 (juvenile male: ZMH K-41912). Fifth limb: A, distal part; B, 4th and 5th exopodite segments. C, sixth limb. D, distal part of copulatory limb. Furcal lamella: E, 3rd–5th claws; F, base of 1st and 2nd claws.

Maxillula (Fig. 20H, I). 1st, 2nd and 3rd endites with 10, 7 and 8 bristles, respectively. Bristle of coxale broken. Basale with 2 bristles (1 long and 1 medium-sized). Endopodite: 1st segment with 2 long spinous α-bristles; and 3 spinous β-bristles (1 inner short, 1 outer, long and stout long, 1 median, medium-lenght); cutting edge with rounded small teeth. 2nd segment with 4 usual a-bristles (Fig. 20I); 3 strongly pectinate b-bristles; 3 c-bristles (2 pectinate and 1 bristle-like); 2 strongly pectinate and 1 bare d-bristles. Exopodite with 2 long, terminal and 1 shorter marginal plumose bristles (Fig. 20H).

Fifth limb (Figs 21E–G, 22A, B). Epipodial appendage with 68 long, plumose bristles and 1 short, spinous, proximal bristle. Protopodite of left limb with straight, thick, sclerotized, distally rounded anterior process (Fig. 21E, F). Protopodite of right limb similar to left limb, but with concave dorsal margin. Exopodite: main tooth of 1st segment with 5 pectinate teeth (Fig. 21G); plus 1 distally pointed, proximal process; plus 1 spinous bristle (with about 2–3 middle spines). Inner lobe of 3rd segment with 3 bristles (1 short, plumose and 2 long, simple bristles) (Fig. 22A). Outer lobe with 2 long, plumose bristles (Fig. 22A). 4th and 5th segments fused (i.e. no suture) (Fig. 22A, B). 4th segment with 3 bristles (Fig. 22B). 5th segment with 2 spinous bristles (Fig. 22B). 3rd to 5th segments hirsute (Fig. 22A, B).

Sixth limb (Fig. 22C). Epipodial appendage with 4 bare bristles (proximal bristle shortest and with basal tubercle). 1st endite with 5 plumose bristles (2 long, distal and 3 short, medial). 2nd endite with 4–5 plumose bristles (2 long, distal and 2-3 short, medial). 3rd endite with 5 bristles (1 medial and 2–3 distal, plumose bristles, and 1–2 spinous bristles). 4th endite with 7–8 bristles, from these 1–2 are medial and 6 are distal (shorter, medial bristle and distal bristle bare, others bristles plumose). Distal segment of both left and right limbs with 11–13 long plumose bristles and 6-8 shorter and spinous (19 in total).

Seventh limb (Fig. 21H). Tip with comb of 15 sub-equal teeth, middle tooth longest and slightly recurved. Stout, crescent-shaped tooth present opposite to comb; serrated ridge with 3 small teeth. Limb with 25 distal bristles (13 dorsal and 8 ventral) with 3 to 4 bells, and 36 proximal bristles (18 dorsal and 18 ventral) with 1 to 4 bells (Fig. 21H).

Copulatory limb (Fig. 22D). Limb reduced, with a longer lobe with 5 proximal bristles and broad, slightly sclerotized, terminal process, and a shorter bare lobe.

Furca (Figs 21I; 22E, F). Each lamella with 10 claws; claws decreasing in length and stoutness posteriorly. 1st claw with stout, proximal and distal, marginal teeth (Fig. 21I). Other claws with slight and slender teeth (Fig. 22E). Right limb with minute tubercle between 1st and 2nd claws (Fig. 22F). 4th claw slightly more slender than 5th claw (Fig. 22E).

Medial eye (Fig. 19C). Large, pigmented.

Lateral eyes (Fig. 19E). Eyes large, with about 21 divided ommatidia.

Bellonci organ (Fig. 19C, D) Slightly decreasing in thickness to tip, distal part separated by suture and with nipple-like process at tip.

Upper lip (Fig. 19C) consisting of unpaired, anterior part with glandular pegs along margin; 2 pairs of short tusks near middle; and unpaired hirsute posterior lobe; anterior and posterior pairs of tusks with one row of glandular pegs.

Anterior body (Fig. 19C) straight and with medium-sized, rounded, anterior process.

Comparisons. Doloria (Dolorietta) sp. nov. 1 species resembles D. (D.) levinsoni and D. (D.) isaacsi , but differs in (Table 4) (1) the shape of the bristle at the base of the coxale endite; and (2) the shortest a-bristle on the ventral margin of the mandibula basale; (3) Exopodite of the fifth limb with fused 4th and 5th segments; and (4) the structure of Bellocini organ. Doloria (D.) sp. nov. 1 differs from D. (D.) levinsoni in (1) the 2 rows of bristles on the infold of the rostrum; (2) the large lateral eyes; and (3) the straight surface of anterior body Doloria (D.) sp. nov. 1 differs from D. (D.) isaacsi by the number of bristles on the endites of the sixth limb (Table 4).

Distribution. Recent. Powell Basin, Atlantic Sector of the Southern Ocean. Bathyal (1179–1996 m).

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

Figures

FIGURE 18. Doloria (Dolorietta) sp. nov. 1 (juvenile male: ZMH K- 41912). Carapace: A, right valve in lateral view; B, rostrum, internal view; C, bristles on rostrum; D, antero-ventral part, internal view; E, bristles on anterior part; F, infold on posterior part.