Doloria (Dolorietta) antarctica, Chavtur, Vladimir G., Brandão, Simone N. & Bashmanov, Alexander G., 2012

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 : 6-17

Doloria (Dolorietta) antarctica sp. nov.

( Figs 2–10 , Tab. 2 )

Holotype. ZMH K- 41897, adult female (CL 4.37 mm); valves on slide; one limb of antennula, anterior of the body, upper lip, Bellonci organ, lateral eyes and medial eye in alcohol; remaining appendages mounted on glass slide.

Type-locality. ANDEEP III, PS 67, ANT XXII/3, St. 150–6, epibenthic sledge, 61º49.14´S – 47º27.51´W to 61º48.53´S – 47º28.16´W, depth 1971–1996 m, 20 March 2005.

Paratypes. ZMH K- 42613, type locality, 2 juveniles in alcohol. ZMH K- 41898, ANDEEP III, PS 67, ANT XXII/3, St. 151–1, Agassiz trawl, 61º45.51´S – 47º7.49´W to 61º45.31´S – 47º7.84´W, depth 1179–1188 m, 20 March 2005: 1 adult male (carapace length 3.80 mm), valves in micropaleontological slide; one seventh limb in alcohol; remaining appendages mounted on glass slide; plus 3 juveniles in alcohol.

Etymology. The species name refers to the region where it comes from.

Diagnosis. Adult female. Carapace: length 4.37 mm; infold behind rostrum with 14 short and 2 long bristles forming a vertical row. Antenna: bristle on 2nd segment with 17 teeth along the ventral margin. Mandibula: dorsal margin of 2nd endopodite segment with 6 long, 4 medium-sized and 20 short bristles. Fifth limb: 5th exopodite segment separated by a suture from the 4th segment and with 2 bristles. Sixth limb: epipodial appendage with 5 bristles. Seventh limb: tip with comb of 30–31 teeth; limb with a total of 92 bristles. Furca : each lamellae 10–11 claws. Lateral eyes: large, with 20–22 ommatidia. Bellonci organ: cylindrical, distal part separated by suture. Upper lip: with 2 pairs of short tusks. Anterior body: straight, with medium-sized, rounded anterior process.

Adult male. Carapace: length 3.80 mm; infold behind the rostrum with about 20 short, 3 medium-sized and 2 long bristles forming a vertical row. Antenna: length of 1st endopodite segment about 60% of 2nd segment; 3rd segment with large basale and squared tip; proximal bristle as long as 2nd segment. Fifth limb: anterior process of protopodite with rounded tip; 5th exopodite segment separated by suture from 4th segment and with 2 bristles. Sixth limb: epipodial appendage with 5 bristles. Seventh limb: tip with comb of 21 teeth; tooth opposite to the comb with 2 small teeth forming row on each side and with convex proximal part; limb with 76 bristles in total (37 distal and 39 proximal). Lateral eyes: large, with 20–22 ommatidia. Bellonci organ: cylindrical, with nipple-like process at tip.

Description of adult female. Carapace ( Figs 2 ; 3A, B). Length 4.37 mm. Greatest height about 75% of length. Carapace oval with rounded posterior margin and fairly deep incisur with over-hanging rostrum ( Figs 2 A, B; 3A, B); antero-ventral margin angular; surface smooth. Infold broad anteriorly, becoming narrower ventrally, and then slightly broader posteriorly (Fig. 3B). Infold posterior to rostrum with about 14 short and 2 long bristles forming a vertical row ( Figs 2 C, D); 3 long and 1–2 short bristles present around inner margin of incisur; anteroventral and ventral infolds with numerous pairs of unequal bristles and without pores; inner margin of posterior infold with raised list with tiny bristles ( Figs 2 E, F).

Antennula (Fig. 3C, D, G–I). 1st segment bare. 2nd segment with numerous clusters of minute spines along both dorsal and ventral margins. 3rd segment with 2 bristles with short marginal spines, ventral bristle sub-terminal, dorsal bristle proximal. 4th segment with 2 unequal distal bristles with short marginal spines, the longer ventral bristle almost reaches to the end of 5th segment. Sensory bristle of 5th segment with 9 long and 4 shorter proximal filaments, distal margin bare and with bifurcate tip (Fig. 3G, H, I). Medial bristle of 6th segment with marginal spines and as long as the length of the 5th segment. 7th segment: a-bristle bare and longer than the bristle of 6th segment (Fig. 3G); b-bristle with 2 short proximal and 3 long distal, pectinate, marginal filaments; c-bristle with 8 long, proximal and 1 short, distal, pectinate, marginal filaments. 8th segment: d- and e-bristles bare and longer than bbristle; g-bristle longer than f-bristle, both with 8 long proximal and 1 short, distal, pectinate filaments.

Antenna (Figs 3J, K; 4A–C; 8I). Protopodite as long as exopodite, and with fairly long medial bristle (Fig. 4C). Endopodite 3-segmented (Figs 3K; 8I): 1st segment with 4 proximal bristles (3 short and 1 long), and 1 long, distal bristle (Figs 3K; 4C). 2nd segment bare. 3rd segment with long, distal filament barely longer than endopodite. Exopodite: basal spines present on 3rd to 9th segments (all spines not bifurcate at tip)(Fig. 3J); spines on distal segments longer than those on proximal segments; spine on 9th segment about 80% length of 8th segment (Fig. 3J). Bristle of 2nd segment reaching 9th segment, and with about 17 teeth along ventral margin and about 6 teeth at middle on dorsal margin (Fig. 4A, B). Natatory setules present on bristles on segments 3 to 8. 9th segment with 4 bristles, all with natatory setules, dorsal bristle shorter than others.

Mandibula (Figs 4D–F; 5A–C; 6A). Coxale endite strongly spinous; distally broad and rounded, with 2 stout spines at tip (both with additional stout marginal teeth) and minute peg between them; short bristle with blunt tip present at base of endite (Fig. 5C). Basale: dorsal margin with 1 short, proximal bristle, 1 long, distal bristle and 2 long, distal bristles; ventral margin with 3 medium-sized (1 short absent) a-bristles, 1 short and 1 long b-bristles, 1 medium-sized c-bristle, and 1 long d-bristle (Fig. 4D, F). Exopodite reaches beyond of end of 1st endopodite segment; with pointed tip hirsute on disto-dorsal margin, and 2 bristles (1 medium-sized and 1 long) (Figs 4D, 5A). 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 2–3 groups of bristles with 1, 0 and 2 or 1, 1 and 2 slender bristles in each group; dorsal margin with 6 long, 4 medium-sized and 20 short bristles (short bristles with fairly long spines along ventral margin) (Fig. 4E); distal segment with 2 long and 1 shorter claw-like bristles and 4 simple bristles (1 medium-sized, dorsal, plus 2 long, plus 1 minute, ventral); 2 long, claw-like bristles with some long proximal spines along ventral margin (Fig. 5B).

Maxillula (Figs 4G, H). 1st, 2nd and 3rd endites with 12, 6 and 6 bristles, respectively. Coxale with 1 stout plumose bristle. Basale with 2 (?) long bristles. Endopodite: 1st segment with 2 long α-bristles and 3 β-bristles (1 inner, short bristle, 1 outer, stout, long bristle with marginal teeth, and 1 middle bristle); cutting edge with rounded small teeth (Fig. 4G, H). 2nd segment with 4 usual a-bristles, 3 strongly pectinate b-bristles, 3 c-bristles (2 pectinate and 1 bristle-like), plus 2 strongly pectinate and 1 bare d-bristles. Exopodite with 2 long, distal and 1 shorter marginal bristles (1 marginal and 1 long bristles pectinate).

Fifth limb (Fig. 5D–H). Epipodial appendage with 56–57 plumose bristles. Protopodite with straight, relatively thick, sclerotized, anterior process on distal margin (Fig. 5H, G). Exopodite: anterior surface of 1st segment with 1 proximal bristle (with marginal setules) and 3 distal, spinous bristles (1 bristle with long middle setules); main tooth consists of 6 pectinate teeth, proximal triangular process with rounded tip and 1 spinous bristle (with about 5–6 middle spines) distally present near process (Fig. 5E, F). 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 5 bristles; 5th segment separated by suture from 4th segment and with 2 bristles (1 plumose) (Fig. 5D). 3rd to 5th segments hirsute.

Sixth limb (Figs 5I –K; 6B). Epipodial appendage with 5 bristles (Fig. 6B). 1st endite with 5 plumose bristles (2 long, distal and 3 short, medial). 2nd endite with 5 plumose bristles (2 long, distal and 3 short, medial). 3rd endite with 5–6 bristles (1 proximal, spinous and others plumose, 1 short and 3–4 long). 4th endite with 8 bristles (5 plumose and 1 spinous and 2 bare) (Fig. 5I). Distal segment with 25 bristles (12 long, plumose and others shorter, spinous and bare) (Fig. 6B).

Seventh limb (Fig. 6C, D). Tip with comb of 30–32 teeth; proximal teeth shorter than distal teeth and with square ends; middle tooth longer than others and recurved Fig. 6C). Stout crescent-shaped tooth present opposite to comb; serrated ridge with 2 teeth (Fig. 6C, D). Right limb with 92 bristles in total: 47 distal (29 dorsal and 18 ventral) with 1 to 7 bells, and 45 proximal bristles (22 dorsal and 23 ventral) with 4 to 7 bells. Left limb with 25 dorsal and? ventral distal bristles with 1 to 7 bells; and 22 dorsal and 19 ventral proximal bristles with 5 to 7 bells.

Furca (Fig. 4I, Fig. 6E-H). Left lamella with 10 claws; 2nd claw stouter than 1st claw; 3rd claw slightly more slender than 4th claw; others claws decreasing in length and stoutness posteriorly along lamella (Fig. 4I). Right lamella with 11 claws; 2nd claw usual; 4th claw slightly more slender than 5th claw (Fig. 6E).

Lateral eye (Fig. 3D, F). Eyes large, with about 20–22 ommatidia.

Medial eye (Fig. 3C, D). Large, pigmented.

Bellonci organ (Fig. 3C–E). Cylindrical with nipple-like process at tip.

Upper lip (Fig. 3C). Lip 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. 3C). Straight with medium-sized, rounded anterior process.

Eggs single female collected with 26 eggs.

Description of adult male. Carapace (Fig. 7A–D). Length 3.80 mm. Greatest height (~70% CL) at midlength. Carapace shape similar to that of female, but is slightly smaller and less high (Fig. 7A, B). Infold broad in the anterior of the shell, narrow ventrally and slightly broader posteriorly. Infold posterior to rostrum with about 20 short, 3 medium-sized and 2 long bristles forming a vertical row (Fig. 6C). Bristles absent from around inner margin of incisor. Antero–ventral, ventral and posterior infolds same as those of female.

Antennula (Figs 7E–K; 8A, B; 9B). Segments 1st to 4th same as those of female. Sensory bristle of 5th segment with about 9 proximal and 4 distal filaments (3 proximal with 3 marginal spines and 1 distal bare) and bifurcate tip (Fig. 7F). Medial bristle of 6th segment short and somewhat shorter than this segment (Fig. 7E, F). 7th segment: a-bristle as usual and about twice as long as bristle of 6th segment; b-bristle with short, proximal filament with bulbous base followed by disc, and small, wart-like process (bulbous base of filament with medial, crenulated, buttonlike disc) (Fig. 8A); 1 medial filament with 4 small discs; 1 bare, distal filament, and 3 distal filaments (1 short, 1 medium-sized and 1 long) (Fig. 7E); c-bristle with a stout proximal filament similar to that on the b-bristle, 1 filament with 4 small discs, 6 distal filaments and bifurcate tip (Fig. 7E, F, 8A, 8B). 8th segment: d- and e-bristles bare and about 1/3 length of g-bristle; f- and g-bristles with 8 filaments and bifurcate tip (Fig 7F-K, 8B).

FIGURE 3. Doloria (Dolorietta) antarctica sp. nov. (Holotype female: ZMH K-41897). A and B, right valve, lateral and internal views; C, anterior of body showing medial eye, Bellonci organ, antennula and upper lip; D, medial eye, lateral eye, Bellonci organ and antennula; E, Bellonci organ; F, lateral eye. Antennula: G, distal part; H and I, proximal and distal parts of bristle on 5th segment. Antenna: J, distal part of exopodite; K, endopodite.

FIGURE 4. Doloria (Dolorietta) antarctica sp. nov. (Holotype female: ZMH K-41897). Antenna: A, bristle on 2nd exopodite segment and B, its distal part; C, proximal part of endopodite. Mandibula: D, whole limb; E, distal part of 2nd endopodite segment; F, ventral margin of basale. G and H, cutting edge on 1st endopodite segment of maxillula. I, left furcal lamella.

5. Doloria (Dolorietta) antarctica sp. nov. ZMH K-41897). A, 1 podite segment and part of basale; B, distal part of endopodite. First limb: C, coxale endite; D, 4th and 5th exopodite segments; E, main tooth on 1st exopodite segment; F, bristle near of main tooth on 1st exopodite segment; G and H, anterior process of protopodite. Sixth limb: I, endites on limb; J, K - these bristles are marked with an *in Fig. 6B.

FIGURE 6. Doloria (Dolorietta) antarctica sp. nov. (Holotype female: ZMH K-41897). A, base of main claw on maxillula; B, distal segment and epipodite of sixth limb. Bristles marked with * see Fig. 5 J, K. Seventh limb: C, distal part; D, process opposite comb. Furca : E, 1st–5th claws; F, middle part of 1st claw; G and H, base and middle part of 2nd claw.

FIGURE 7. Doloria (Dolorietta) antarctica sp. nov. (paratype male: ZMH K-41898). Carapace: A and B, right valve, lateral and internal view; C, anterior part, internal view; D, infold on posterior part. Antennula: E, whole limb; F, distal part of limb; G, distal part of bristle on 5th segment; H, distal part of b-bristle; I, distal part of c-, f- and g-bristles; J, middle part of g-bristle; K, distal part of e-bristle.

FIGURE 8. Doloria (Dolorietta) antarctica sp. nov. (paratype male: ZMH K-41898, A–H; Female: ZIM–5–41897, I). Antennula: A, distal part; B, proximal part of bristle on 5th segment. Antenna: C, exopodite; D, distal part of exopodite; E, bristle on 2nd exopodite segment; F, endopodite of right limb; G, distal part of endopodite; H, distal part of hook-like; I, endopodite of right limb (female).

FIGURE 9. Doloria (Dolorietta) antarctica sp. nov. (paratype male: ZMH K-41898). A, lateral eyes; B, proximal filament on c-bristle of antennula. Mandibula: C and D, 2nd endopodite segment; E, distal part of coxale endite. Maxillula: F, endopodite, exopodite and basale (distal bristles not shown); G, basale and endites (without bristles); H, distal part; I, cutting edge on 1st endopodite segment. Fifth limb: J, 3rd–5th exopodite segments; K, bristle near main tooth on 1st exopodite segment; L, anterior process on protopodite; M, medial eye and Bellonci organ.

Antenna (Fig. 8C–H). Protopodite similar to that of female. Endopodite 3-segmented (Fig. 8F): 1st segment with 5 bristles, 4 in a proximal group (1 long and 3 short), and a single long, medial bristle. 2nd segment with distal group with 3 short bristles. 3rd segment recurved, with broad base and 1 proximal filament as long as 2nd segment and 2 minute, distal bristles (Fig. 8G, H). Exopodite: basal spines on 3rd to 9th segments as in the female (Fig. 8D). Bristle of 2nd segment reaches to the 9th segment, and has about 7–8 teeth along ventral margin, the dorsal margin is bare (Fig. 8C, E). Natatory setules present on bristles on segments 3 to 8. 9th segment with 4 bristles, all with natatory setules, dorsal bristle shorter than others.

Mandibula (Fig. 9C–E). Basale, exopodite, 1st and 3rd endopodite segments same as those of female. Coxale endite distally narrow and slowly decreasing in width to the tip (Fig. 9E). Ventral margin of 2nd endopodite segment with 3–4 groups of bristles with 1, 1, 2, and 2 or 1, 1, 1 and 2, slender bristles in each group (Fig. 9C, D).

Maxillula (Fig. 9F–I). 1st, 2nd and 3rd endites with 11, 6 and 6 bristles respectively. Cutting edge of 1st endopodite segment with small, rounded and pointed teeth (Fig. 9F, I). Distal segment with 4 usual a-bristles, 2 pectinate b-bristles, 4 c-bristles (3 pectinate and 1 bare) and 3 pectinate d-bristles (Fig. 9H).

Fifth limb (Fig. 9J–L). Epipodial appendage with about 70 plumose bristles. Protopodite with straight, relatively thick, sclerotized anterior process with ball-shaped tip (Fig. 9L). Endopodite: 1st segment with main tooth similar to that of female, and a spinous bristle with 2 stout teeth. 4th segment with 6 spinous bristles. 5th segment separated by suture from the 4th segment and with 2 spinous bristles (Fig. 9J).

Sixth limb. Epipodite and endites similar to those of female. Distal segment with 29–31 bristles, similar in shape and position to those of female.

Seventh limb ( Fig. 10 A). Tip with comb of 21 teeth, proximal teeth with square ends are shorter than distal teeth; middle tooth stout, recurved, and longer than others. Stout crescent-shaped tooth opposite to comb; and a serrated ridge with 2 teeth present on either side of crescent-shaped tooth. Limb with a total of 76 bristles (all with 4 to 7 bells): 37 distal (20 dorsal and 17 ventral), and 39 proximal (17 dorsal and 22 ventral).

Furca . Each lamella with 11 claws, all separated from lamella by suture; 4th claw slightly more slender than 5th claw.

Copulatory limbs ( Figs 10 B–F). Consisting of lobes: longer lobe with 4 bristles on 1st segment. Broad, sclerotized, hook-like process at terminus of 2nd segment. Shorter lobe with 6 bristles, and terminating in narrow, sclerotized process.

Lateral eyes (Fig. 9A). Large, with about 2–22 ommatidia.

Medial eye (Fig. 9K). Large, pigmented.

Bellonci organ (Fig. 9K). Cylindrical, relatively short and with nipple-like process at tip.

Comparisons. Doloria (Dolorietta) antarctica sp. nov. is closely related to D. (D.) isaacsi , but differs in ( Table 1): (1) its smaller size; (2) the number of bristles posterior to the female rostrum; (3) the shape of bristles on antero-ventral and ventral margins; (4) the number of teeth on the bristle of 2nd exopodite segment of the antenna; (5) the comb of the seventh limb; (6) the number of bristles on the basale and 2nd endopodite segment of the mandibula; (7) the distal segment of sixth limb; (8) the seventh limb; (9) the shape of the Bellonci-organ; (10) the shape of the process on the protopodite of the mandibula; (11) the structure of the upper lip; (12) the shape of the anterior body; (13) the armature and shape of the copulatory limb..

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

Figures

FIGURE 2. Doloria (Dolorietta) antarctica sp. nov. (Holotype female: ZMH K- 41897). Carapace. A, left valve, lateral view; B and C, rostrum and incisor, lateral and internal views; D, rostrum, internal view; E and F, antero-ventral infold.

FIGURE 10. Doloria (Dolorietta) antarctica sp. nov. (paratype male: ZMH K- 41898). A, distal part of seventh limb. Copulatory limbs: B, whole limb, C and D, distal part of lobes; E and F, bristles on lobes.