Philine malaquiasi Valdés, Cadien & Gosliner, 2016, sp. nov.

Philine malaquiasi sp. nov.

Figures 18–19

Type material. HOLOTYPE: Beaufort Sea (70º10.3’N, 144º35.5’W), 27 m depth, R/ V Glacier (WBS-72) (Oregon State University OTB-453), 8 Aug 1972, 7 mm preserved length (LACM 3436).

Other material examined. North of Point Barrow, Beaufort Sea, Arctic Ocean (71º28.10’N, 156º15’W), 16 m depth, R/ V Alumiak (Oregon State University SMG-1381), 19 Aug 1976, 1 shell, 2.7 mm long (LACM 1976- 675.1). North of Point Barrow, Beaufort Sea, Arctic Ocean (71º28’N, 156º18.30’W), 20 m depth, R/ V Alumiak (Oregon State University SMG-1371, SMG-1372, SMG-1375, SMG-1376), 19 Aug 1976, 3 specimens, 2.2–4 mm preserved length + 3 shells, 2.2–5 mm long (LACM 1976-672.1). North of Point Barrow, Beaufort Sea, Arctic Ocean (71º27.10’N, 156º23.10’W), 26 m depth, R/ V Alumiak (Oregon State University SMG-1367), 19 Aug 1976, 1 shell, 3.2 mm long (LACM 1976-676.1). Beaufort Sea, Arctic Ocean (71º12’N, 148º35’W), R/ V Glacier (WBS-71) (Oregon State University OTB-419), 360 m depth, 6 Sep 1971, 1 shell, 6 mm long (LACM 71-362.8). Northwest of Cape Halkett, Beaufort Sea, Arctic Ocean (71º8.40’N, 152º39.50’W), 25 m depth, R/ V Alumiak (Oregon State University SMG-1084, SMG-1087), 26 Oct 1975, 1 specimens, 2.5 mm preserved length + 1 shell, 4.1 mm long (LACM 1975-702.1). Beaufort Sea, Arctic Ocean (70º34.8’N, 144º23.1’W), R/ V Glacier (WBS-72) (Oregon State University OTB-450), 71 m depth, 7 Aug 1972, 1 shell, 6.6 mm long (LACM 72-243.26). Northwest of Beechey Point, Beaufort Sea, Arctic Ocean (70º33.10’N, 149º34.30’W), 15 m depth, R/ V Alumiak (Oregon State University SMG-1434), 24 Aug 1976, 2 shells, 2.4–2.9 mm long (LACM 1975-674.1). Beaufort Sea, Arctic Ocean (70º31.75’N, 147º33.5’W), R/ V Glacier (WBS-72) (Oregon State University OTB-463), 20 m depth, 15 Aug 1972, 1 shell with dried soft parts, 6 mm long, 1 specimen 9 mm preserved length (LACM 72-254.16). 2.35 miles northeast of Stump Island, Return Islands, Beaufort Sea, Arctic Ocean (70º27.4’N, 148º34.7’W), 9 m depth, 17 Aug 1988, 1 shell with dried soft parts, 2.2 mm long, leg. Rae Baxter (LACM 88-141.12). Northeast of Prudhoe Bay, Beaufort Sea, Arctic Ocean (70º24.50’N, 147º30.30’W), 5 m depth, R/ V Alumiak (Oregon State University SMG-1442), 27 Aug 1976, 1 specimen, 1.9 mm preserved length (LACM 1976-671.1). Northeast of Prudhoe Bay, Beaufort Sea, Arctic Ocean (70º24.10’N, 147º29.50’W), 10 m depth, R/ V Alumiak (Oregon State University SMG-1451), 28 Aug 1976, 2 shells, 1.2–1.8 mm long (LACM 1976-673.1). West end of Pole Island, Beaufort Sea, Arctic Ocean (70º15.4’N, 147º06.1’W), 7 m depth, 9 Aug 1988, 3 shells with dried soft parts, 1.5–2.5 mm long (LACM 88-138.11). 2.75 miles north of Savakvik Point, northeast of Mikkelsen Bay, Beaufort Sea, Arctic Ocean (70º13.9’N, 146º53.0’W), 4 m depth, 9 Aug 1988, 1 shell with dried soft parts, 2.5 mm long, leg. Rae Baxter (LACM 88-139.16). 3 miles northwest Savakvik Point, central Mikkelsen Bay, Beaufort Sea, Arctic Ocean (70º12.6’N, 146º59.7’W), 5 m depth, 11 Aug 1988, 1 shell with dried soft parts, 2.2 mm long, leg. Rae Baxter (LACM 88-140.11). Northeast of Baxter Island, Beaufort Sea, Arctic Ocean (70º11.10’N, 143º31.30’W), R/ V Alumiak (Oregon State University SMG-1460), 31 Aug 1976, 1 shell, 4 mm long (LACM 1976-677.1). Beaufort Sea (70º10.3’N, 144º35.5’W), 27 m depth, R/ V Glacier (WBS-72) (Oregon State University OTB-453), 8 Aug 1972, 15 specimens, 4–7 mm preserved length (LACM 72-246.25). Beaufort Sea, Arctic Ocean (70º10.3’N, 144º33.5’W), R/ V Glacier (WBS-72) (Oregon State University OTB-453), 27 m depth, 8 Aug 1972, 1 shell, 5 mm long (LACM 72-246.24). 3.3 miles northwest of Kangigivik Point, west side of Camden Bay, Beaufort Sea, Arctic Ocean (70º03.5’N, 145º18.4’W), 8 m depth, 18 Aug 1988, 2 shells with dried soft parts, 2.5–3 mm long, leg. Rae Baxter (LACM 88-143.14). 2.5 miles west of northeast end of Anderson Point, east side of Camden Bay, Beaufort Sea, Arctic Ocean (70º01.5’N, 144º35.3’W), 10 m depth, 21 Aug 1988, 2 shells with dried soft parts, 1.8–2.9 mm long, leg. Rae Baxter (LACM 88-146.13). West end of Collinson Point, Camden Bay, Beaufort Sea, Arctic Ocean (70º00.7’N, 144º46.3’W), 10 m, 21 Aug 1988,>20 shells with dried soft parts, 2–3.2 mm long, leg. Rae Baxter (LACM 88-147.20).

Description. Live animals unknown. Preserved specimens to 12 mm long. Body oval, about twice as wide as long (Figs. 18 A–B). Cephalic shield reduced, restricted to the anterior-most part of the body, deeply notched posteriorly. Parapodia small and fleshy, only visible on a lateral view of animal. Shell to 9 mm long, bulloid, elongate (Fig. 18 C–H). Aperture, relatively narrow, shorter than shell. Sculpture consisting of conspicuous spiral lines, formed by partially fused punctuations (Fig. 18 I).

Digestive system with a short buccal bulb, surrounded by central nervous system anteriorly (Fig. 19 A). Two large salivary glands connect with buccal bulb at insertion point of esophagus. Esophagus elongate, simple, thinwalled. Gizzard and gizzard plates absent. Radular formula 12–13 x 2.1.0.1.2. Inner lateral teeth broad, lacking denticles or with rudimentary denticles (Fig. 18 J). Outer teeth hook-shaped.

Reproductive system with a short prostate, connected to an undifferentiated penis (Fig. 19 B).

Range. Beaufort Sea, Arctic Ocean (Fig. 3 C). Depth range 4–360 m depth, most records above 30 m depth.

Etymology. Dedicated to Manuel A. E. Malaquias for his seminal work on the phylogeny of Cephalaspidea in general and Philine in particular.

Remarks. Philine malaquiasi sp. nov. is the only species from the study area with a notched posterior end of the cephalic shield. It is most similar morphologically to Philine baxteri sp. nov. but lacks denticles on the innermost lateral teeth. Philine malaquiasi sp. nov. appears to be restricted to the Beaufort Sea in the Arctic Ocean, whereas P. baxteri sp. nov. is found in the Gulf of Alaska, Aleutian Islands and Bering Sea. Philine malaquiasi sp. nov. is very similar to the North Atlantic species Philine lima (Brown, 1827) as described by Ohnheiser and Malaquias (2013). Both species share the same body profile, as well as a similar reproductive anatomy and nearly identical radulae. Differences include the shape of the shell, more narrow and elongate in P. l i m a, which also has a distinct spire with the protoconch visible. Also, the prostate of P. lima is much shorted than in Philine malaquiasi sp. nov.

A specimen from the Kara Sea identified as Retusophiline polaris (Aurivillius, 1887) by Chaban and Martynov (2006: pl. 128, fig. B) could belong to the same species, but the Kara Sea animal has a much more quadrangular shell, with an expanded, almost triangular aperture.