Dentalina antarctica Parr, 1950

Guðmundsson, Guðmundur, Cedhagen, Tomas & Andersen, Tom, 2022, Taxonomy and distribution of recent species of the subfamily Nodosariinae (Foraminifera) in Icelandic waters, European Journal of Taxonomy 824 (1), pp. 1-74 : 5-7

Dentalina antarctica Parr, 1950

Fig. 1

Dentalina antarctica Parr, 1950: 329 , pl. 11 figs 26–27.

Laevidentalina antarctica – Eiland & Guðmundsson 2004: 198, 200, pl. 1 fig. e, pl. 3 fig. b.

Material examined

ICELANDIC WATERS • 3; 66.7592° N, 20.0878° W; RP sledge; depth 293 m; 3°C; 34.86 ppt; 9 Jul. 1992; BIOICE 2149 ; IINH 40405 • 1; 64.2158° N, 25.2883° W; RP sledge; depth 265 m; 6.36°C; 35.09 ppt; 3 Sep. 1992; BIOICE 2219 ; IINH 40406 • 1; 63.8167° N, 24.3736° W; RP sledge; depth 296 m; 6.96°C; 35.11 ppt; 4 Sep. 1992; BIOICE 2229 ; IINH 40407 • 6; 63.4528° N, 24.6875° W; RP sledge; depth 296 m; 6.92°C; 35.11 ppt; 4 Sep. 1992; BIOICE 2237 ; IINH 40408 • 1; 63.2528° N, 25.8286° W; Triangle dredge ; depth 852 m; 5.41°C; 34.99 ppt; 5 Sep. 1992; BIOICE 2251 ; IINH 40409 • 2; 63.1439° N, 24.9833° W; RP sledge; depth 313 m; 6.97°C; 35.12 ppt; 8 Sep. 1992; BIOICE 2273 ; IINH • 2; 63.2506° N, 22.7936° W; RP sledge; depth 263 m; 7.12°C; 35.13 ppt; 10 Sep. 1992; BIOICE 2308 ; IINH 40412 • 1; 62.7167° N, 12.7167° W; RP sledge; depth 803 m; unknown; unknown; 4 May1993; BIOICE 2334 ; IINH 40413 • 2; 63.25° N, 22.2° W; detr. sledge (Sneli); depth 288 m; 6.92°C; 35.1 ppt; 30 Jun. 1993; BIOICE 2392 ; IINH 40411 • 2; 63.2514° N, 22.2033° W; RP sledge; depth 291 m; 6.92°C; 35.1 ppt; 30 Jun. 1993; BIOICE 2393 ; IINH 40410 • 1; 63.1306° N, 21.9422° W; detr. sledge (Sneli); depth 511 m; 6.74°C; 35.09 ppt; 1 Jul. 1993; BIOICE 2400 ; IINH 40414 • 5; 63.175° N, 20.0692° W; RP sledge; depth 778 m; 5.5°C; 35.03 ppt; 3 Jul. 1993; BIOICE 2427 ; IINH 40415 • 2; 63.1167° N, 19.95° W; detr. sledge (Sneli); depth 1072 m; 4.8°C; 35 ppt; 3 Jul. 1993; BIOICE 2429 ; IINH 39705 • 2; 63.1417° N, 19.9556° W; RP sledge; depth 1016 m; 4.8°C; 35 ppt; 3 Jul. 1993; BIOICE 2430 ; IINH 39706 • 2; 63.0689° N, 19.8592° W; detr. sledge (Sneli); depth 1207 m; 4.45°C; 34.99 ppt; 3 Jul. 1993; BIOICE 2431 ; IINH 40417 • 1; 63.2389° N, 19.5361° W; RP sledge; depth 965 m; 5.48°C; 35.03 ppt; 3 Jul. 1993; BIOICE 2435 ; IINH 40418 • 1; 63.2667° N, 20.4° W; Triangle dredge; depth 138 m; unknown; unknown; 4 Jul. 1993; BIOICE 2442 ; IINH 40439 • 2; 63.1233° N, 21.6119° W; detr. sledge (Sneli); depth 647 m; 6.09°C; 35.06 ppt; 5 Jul. 1993; BIOICE 2471 ; IINH 40416 • 2; 64.1722° N, 27.7194° W; RP sledge; depth 1042 m; 4.2°C; 34.93 ppt; 2 Sep. 1994; BIOICE 2697 ; IINH 40421 • 1; 64.5167° N, 25.725° W; detr. sledge (Sneli); depth 358 m; 5.59°C; 35.04 ppt; 6 Sep. 1994; BIOICE 2716 ; IINH 40423 • 1; 64.3861° N, 27.3194° W; detr. sledge (Sneli); depth 711 m; 6°C; 35.05 ppt; 7 Sep. 1994; BIOICE 2726 ; IINH 40422 • 5; 63.4183° N, 16.8444° W; RP sledge; depth 272 m; 7.21°C; 35.15 ppt; 25 Aug. 1995; BIOICE 2830 ; IINH 40426 • 1; 62.8394° N, 18.0117° W; RP sledge; depth 976 m; 3.26°C; 34.98 ppt; 27 Aug. 1995; BIOICE 2849 ; IINH 40427 • 2; 61.8394° N, 16.8906° W; RP sledge; depth 2270 m; 2.37°C; 34.95 ppt; 29 Aug. 1995; BIOICE 2859 ; IINH 40425 • 1; 61.1717° N, 18.0492° W; RP sledge; depth 2400 m; 2.07°C; 34.95 ppt; 30 Aug. 1995; BIOICE 2863 ; IINH 40428 • 3; 64.6281° N, 27.2411° W; RP sledge; depth 554 m; 6.35°C; 35.06 ppt; 22 Aug. 1996; BIOICE 2873 ; IINH 40424 • 1; 65.1722° N, 27.0694° W; RP sledge; depth 229 m; 6.14°C; 35.06 ppt; 23 Aug. 1996; BIOICE 2884 ; IINH 40429 • 2; 65.0433° N, 25.8742° W; RP sledge; depth 163 m; 6.34°C; 35.06 ppt; 30 Aug. 1996; BIOICE 2976 ; IINH 40441 • 1; 64.9225° N, 25.7775° W; Triangle dredge ; depth 183 m; 6.22°C; 35.06 ppt; 30 Aug. 1996; BIOICE 2978 ; IINH 40440 • 1; 63.7667° N, 14.85° W; RP sledge; depth 216 m; 7.67°C; 35.16 ppt; 5 Jul. 1997; BIOICE 2994 ; IINH 40443 • 1; 61.3722° N, 15.3272° W; RP sledge; depth 2133 m; 3.29°C; 34.95 ppt; 7 Jul. 1997; BIOICE 3012 ; IINH 40431 • 4; 63.9969° N, 14.1558° W; RP sledge; depth 221 m; 7.59°C; 35.16 ppt; 10 Jul. 1997; BIOICE 3061 ; IINH 40438 • 1; 63.9981° N, 14.1561° W; detr. sledge (Sneli); depth 218 m; 7.59°C; 35.16 ppt; 10 Jul. 1997; BIOICE 3062 ; IINH 40430 • 1; 66.4911° N, 28.0678° W; Triangle dredge ; depth 334 m; 0.55°C; 34.78 ppt; 26 Aug. 1999; BIOICE 3154 ; IINH 40432 • 2; 61.2403° N, 27.9272° W; Triangle dredge ; depth 1005 m; 4.6°C; 34.97 ppt; 31 Jul. 2000; BIOICE 3183 ; IINH 40433 • 1; 63.3289° N, 25.265° W; RP sledge; depth 306 m; 7.49°C; 35.17 ppt; 11 Sep. 2003; BIOICE 3605 ; IINH 40436 • 1; 63.7533° N, 25.7064° W; detr. sledge ( Sneli ); depth 365 m; 7.1°C; 35.15 ppt; 11 Sep. 2003; BIOICE 3607 ; IINH 40434 • 1; 64.2564° N, 26.0536° W; detr. sledge (Sneli); depth 345 m; 6.95°C; 35.14 ppt; 12 Sep. 2003; BIOICE 3613 ; IINH 40435 .

Description

Test shape elongate, nearly cylindrical, slightly curved, rarely straight, somewhat tapering, barely nodular, initial end rounded. Length of test usually 2–3 mm, the largest 5 mm; test width commonly 0.5–0.6 mm. Chambers initially subglobular then cylindrical and more elongated as added; number of chambers often 4–6, the largest specimen has 8. Chamber arrangement rectilinear; initial 3–6 chambers in microsphere are planispiral and evolute, forming about half of a whorl ( Fig. 1A ). Initial chambers embrace about half of the previous chambers, later embracement is minimal; sutures are oblique. Aperture radial, nearly central, slightly raised, with variable number (11–19) of symmetrically arranged tines, sometimes partly fused in the center ( Fig. 1C ); rarely converging around central opening ( Fig. 1D ). Surface smooth, without secondary surface laminations (atelo-lamellar). Wall finely perforated, medium thick, semitransparent, rarely thin.

Remarks

The type description states that “aperture is large and circular, with a radiate edge,” probably because the aperture is damaged. In many of the examined specimens the tip of the aperture is broken, resulting in a round opening with a jagged rim. Type description and figures conform otherwise to the present material, although type locality is the Antarctic. The citation of Nodosaria (D.) communis in Brady (1884) as synonym in Eiland & Guðmundsson (2004) is a mistake, as this reference is accepted as Dentalina aphelis ( Loeblich & Tappan, 1986) ( Jones 1994) , which differs from D. antarctica in being much more tapering and curved; aperture is conical and protruding, with radial bars fused in the center ( Loeblich & Tappan 1986).

The initial part in both generations of the species Marginulina similis d’Orbigny, 1846 is slightly but not fully coiled, and resembles D. antarctica in shape. The species M. similis was not found in the present material, although it has been recorded in the North Atlantic and off the British Isles ( Cushman 1923) under the name Marginulina glabra d’Orbigny, 1826 .

Four microspheric specimens were found among the 70 examined specimens of the present material. Diameter of proloculus in megalospheres is about 0.25 mm, but less than 0.02 mm in the microspheres.

Figures

Fig. 1. Dentalina antarctica Parr, 1950. A. Side view of a young microsphere (BIOICE 2149, IINH 40405) with a spiral initial end; light source is a combination of Rotterman contrast and dark field, revealing the perforations with apparent coarse appearance. B–C. Side view (B), and apertural view (C) of megalosphere (BIOICE 2237, IINH 40408). D. Apertural view of a megalosphere (BIOICE 2697, IINH 40421). Light source in B–D is a combination of incident light and dark field. Scale bars = 0.25 mm.