Hortia macrocephala Kantor, Lozouet, Puillandre & Bouchet, 2014, new species
Creators: name: Kantor, Yuri
name: Lozouet, Pierre
name: Puillandre, Nicolas
name: Bouchet, Philippe
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Magnoliopsida
Neogastropoda
Pyramimitridae
Hortia
Hortia macrocephala

description: Hortia macrocephala new species
Figures 2 I, 7A–D, 9
Type material. Holotype MNHN 24571, 5 paratypes MNHN 24572.
Type locality. South of New Caledonia, 22º15’S, 167º15’E, 440 m [BIOCAL st. DW77].
Material examined. South of New Caledonia. BIOCAL, st. DW 77, 22º15’S, 167º15’E, 440 m, 35 dd, 11 lv (holotype and paratypes). EXBODI, st. CP 3786, 22º15’S, 167º13’E, 408–442 m, 4 dd, 2 lv; st. CP 3787, 22º13’S, 167º06’E, 223–249 m, 1 dd; st. CP 3811, 21º44’S, 166º38’E, 387–668 m, 1 dd. TERRASSE, st. DW3086, Terrasse sud-est, passe de la Sarcelle, 21°55'S, 167°13'E, 400 m, 4 dd.
Description (holotype) (Fig. 9 A–D). Shell small, narrowly fusiform, with high, elevated spire (LWL/SL 0.46) and attenuated, medium long canal. Shell of ca 1.5 protoconch whorls and 6.5 slightly convex teleoconch whorls. Protoconch (Fig. 9 D) paucispiral, semitransparent, globose, smooth, diameter 670 Μm, height 610 Μm, transition to teleoconch marked by two weak opisthocline ribs. Suture impressed. Besides inconspicuous growth lines, axial sculpture of narrow, closely spaced, sinuous and slightly prosocline ribs, 18 on penultimate whorl, 19 on last whorl. Ribs run from suture to suture on spire whorls and become obsolete on shell base at transition to canal. Spiral sculpture of one weak spiral thread abapically of suture and distinct, broadly spaced, narrow cords, rounded in section, two on first whorl, three starting from second whorl and 19 on last whorl, of which 13 on shell base and canal, more closely spaced. Cords on spire whorls and four cords on last whorl form small but distinct rounded beads at intersection with axial ribs. Aperture low, narrow elongate, 0.37 (together with canal) of SL. Outer lip partially broken, concave at transition to long, narrow, and nearly straight canal. Shallow notch at shoulder. Columella short, straight, smooth. Callus narrow, of thin transparent glaze overlying parietal region. Siphonal notch absent. Canal well differentiated from aperture, recurved abaxially to left. Shell color off-white. Periostracum transparent, yellowish, peeling.
Measurements (holotype): SL 10.4 mm, LWL 4.8 mm, AL (with canal) 3.8 mm, SW 2.6 mm. Maximum SL 11.2 mm.
Radula of holotype (Fig. 7 A–D) short, about 320 Μm long (8.4% of AL), consisting of about 35 rows of teeth, 4–5 nascent, with strong alary processes embracing anterior part of odontophore. Membrane folded along both sides of rachidian. Rachidian teeth with broad base, strongly arched anteriorly, and large cusp, sometimes with indistinct additional serration. Lateral teeth high, triangular, shallowly scoop-shaped. Inner side adjoining rachidian with one to three small additional denticles.
Distribution. South of New Caledonia, alive in 440–442 m, shells from 249 m.
Etymology. The name reflects the large, non-planktotrophic protoconch of the species.
Remarks. The paratypes and other specimens are very similar to the holotype in shell outline. Specimens may have a columella with slight swellings that look like weak columellar plaits, but are caused by threads of the spiral sculpture that are only partially overlaid by a very weak callus. In some specimens, the subsutural spiral thread is more pronounced and also forms beads at intersections with axial ribs.
Hortia macrocephala is most similar in shell outline to Hortia pseudotaranis n. sp., but differs in having more numerous and more closely spaced axial ribs (19 on last whorl in Hortia macrocephala vs. 13 in Hortia pseudotaranis).
description: Published as part of Kantor, Yuri, Lozouet, Pierre, Puillandre, Nicolas & Bouchet, Philippe, 2014, Lost and found: The Eocene family Pyramimitridae (Neogastropoda) discovered in the Recent fauna of the Indo-Pacific, pp. 239-276 in Zootaxa 3754 (3) on pages 253-256, DOI: 10.11646/zootaxa.3754.3.2, http://zenodo.org/record/251551