Hortia paradrillia, Kantor, Yuri, Lozouet, Pierre, Puillandre, Nicolas & Bouchet, Philippe, 2014

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, Zootaxa 3754 (3), pp. 239-276 : 252-253

Hortia paradrillia new species

Figures 2 J, 6, 7E–F, 8

Type material. Holotype MNHN 24568, 3 paratypes MNHN 24569.

Type locality. South of New Caledonia, 23º05’S, 167º45’E, 680–700 m [BIOCAL, st. DW 33].

Material examined. South of New Caledonia: BIOCAL, st. DW 33, 23º10’S, 167º10’E, 675–680 m, 1 lv; st. DW 51, 23º05’S, 167º45’E, 680–700 m, 8 lv, 4 dd (holotype and 3 paratypes); st. DW 70, 23º25’S, 167º53’E, 965 m, 1 lv, 1 dd; st. KG 73, 22º13’S, 167º29’E, 1285 m, 1 dd; st. CP 75, 22º19’S, 167º23’E, 825–860 m, 3 lv, 2 dd. NORFOLK 2, st. DW 2144, 23º09’S, 167º27’E, 1004–1009 m, 1 dd.

Description (holotype; paratypes are very similar to holotype) ( Fig. 6 A–D). Shell small, narrowly fusiform, with high elevated spire (LWL/SL 0.53) and attenuated, medium long canal. Shell consisting of ca 1.5 protoconch whorls and 5.75 slightly convex teleoconch whorls. Protoconch paucispiral, globose, smooth, diameter 1050 Μm, height 840 Μm. In its terminal part there are 3–4 weak opisthocyrt ribs, marking transition to teleoconch. Suture shallowly impressed. Besides inconspicuous growth lines, axial sculpture consisting of narrow, closely spaced, sinuous, prosocline ribs, 17 on penultimate whorl, 18 on last whorl. Ribs run suture to suture on spire whorls and become obsolete on shell base. Spiral sculpture of one weak spiral thread abapical of suture and thin, distinct, rounded, broadly spaced, narrow cords, two on spire whorls, 17 on last whorl, of which 12 on shell base and canal are more closely spaced. Cords on spire whorls and four cords on last whorl form large rounded beads at intersection with axial ribs. Aperture medium high, narrowly elongate, 0.44 (together with canal) of SL. Outer lip slightly convex in upper part and concave at transition to long and narrow canal. Lip forms shallow notch at shoulder in side view. Columella short, nearly straight, smooth. Callus narrow, of thin transparent glaze overlying parietal region. Siphonal notch absent. Canal well differentiated from aperture, narrow, long, abaxially recurved. Shell color light yellowish. Periostracum thin, smooth, transparent, peeling.

Measurements (holotype). SL 8.1 mm, LWL 4.3 mm, AL (with canal) 3.6 mm, SW 2.6 mm. Maximum size SL 9.8 mm (BIOCAL, st. DW 70).

The radula of the holotype was examined ( Fig. 7 E–F). Rachidian tooth with broad base, strongly arched anteriorly, large cusp emanating from posterior edge, and irregularly spaced additional denticles. Lateral teeth high, subtriangular, scoop-shaped, sharply pointed, attached by base only. Inner side adjoining the rachidian with 5–6 small additional cusps.

Anatomy. One specimen was dissected. Despite the poor preservation, it was possible to examine the anterior part of the body and anterior foregut ( Fig. 8 ). Body lacks pigmentation. Operculum absent, foot rather short and broad, with narrow propodium and thickened margin. Head with long, narrow tentacles, eyes absent. Mantle (only partly retrieved) long and narrow, very thin and transparent, except slightly thickened mantle edge. Siphon short. Osphradium very large, occupying nearly half of mantle width, ctenidium long and narrow. Hypobranchial gland very narrow, covered with layer of mucus.

Anterior foregut ( Fig. 8 D-F). Rhynchostome forms a powerful sphincter, protruding into the rhynchocoel. Proboscis short and folded, lying in thin and transparent proboscis sheath. Esophagus after leaving proboscis passes through large nerve ring. Valve of Leiblein not traced, probably absent. Salivary gland single, embracing posterior part of nerve ring. Odontophore with radula protruded backward from retracted proboscis. Mid-gut gland small, opens rather posterior to nerve ring, consists of a sac-like part opening into esophagus and filled with unidentified granular content, and a tubular part that is slightly coiled. Posterior esophagus long and narrow.

Distribution. Southern New Caledonia, live in 675–965 m, shells in 675–1285 m.

Etymology. Paradrillia is a genus of Horaiclavidae (Conoidea) superficially resembling this new species. It is used as noun in apposition.

Remarks. Hortia paradrillia differs from its Recent congeners in having a shorter and stouter shell.

Figures

FIGURE 2. Overview of fossil and Recent Pyramimitridae. A. Endiatoma quadricincta (Cossmann, 1883), MNHN. F. A 47757, Lower Eocene, France. B – C. Pyramimitra terebraeformis (Conrad, 1848), MNHN. F. J 08748, Middle Eocene, USA. D – E. Pyramimitra quadralirata Dockery, 1977, MNHN. F. A 47750, Middle Eocene, USA. F. Hortia priabonica n. sp., MNHN. F. A 47752, Upper Eocene, France. G. Hortia arriuensis Lozouet, 1999, MNHN. F. A 47751, Upper Oligocene, France. H. Hortia pseudotaranis n. sp., New Caledonia, SL 8.4 mm. I. Hortia macrocephala n. sp., New Caledonia, SL 10.4 mm. J. Hortia paradrillia n. sp., New Caledonia, SL 8.1 mm. K. Hortia marshalli n. sp., New Zealand, SL 10.6 mm. L. Hortia spenceri n. sp., New Zealand, SL 9.0 mm. M. Hortia aotearoa n. sp., New Zealand, SL 9.0 mm. N. Hortia solitaria n. sp., South of Madagascar, SL 6.5 mm. O. Teremitra fallax n. sp., Solomon Islands, SL 11.8 mm. P. Teremitra efatensis (Aubry, 1999), Vanuatu, SL 10.8 mm. Q. Teremitra? hortensis (Vinassa de Regny, 1898), Upper Eocene, France. R. Teremitra sp., Taiwan, SL 16 mm. S. Vaughanites? superstes n. sp., Philippines, SL 19.1 mm.

FIGURE 6. Shells of Hortia paradrillia n. sp. A – D. Holotype, SL 8.1 mm. D. Enlarged protoconch. E – G. Paratypes. E. SL 7.0 mm. F. SL 6.4 mm. G. SL 8.0 mm. H. BIOCAL, st. DW 33, 23 º 10 ’ S, 167 º 10 ’ E, 675 – 680 m, SL 8.9 mm. I. BIOCAL, st. DW 51, 23 º 05 ’ S, 167 º 45 ’ E, 680 – 700 m, SL 7.9 mm. All shells at the same scale.

FIGURE 7. Radulae of Recent Hortia species. A – D. Hortia macrocephala n. sp., holotype. A. Entire radular membrane. B. Enlarged lateral teeth. C. Enlarged anteriormost part of radular membrane. D. Enlarged rachidian teeth. E – F. Hortia paradrillia n. sp., holotype. E. Dorsal view of central part of radular membrane. F. Enlarged rachidian and lateral teeth.

FIGURE 8. Anatomy of Hortia paradrillia n. sp. A – B. Anterior part of the body, removed from the shell. C. Anterior part of the mantle. D – E. Right and left views of the organs of the anterior foregut. F. Mid-gut gland, ventral view. Abbreviations: cep. t, cephalic tentacles; col. m, columellar muscle; ct, ctenidium; gmg, granulated part of the mid-gut gland; hg, hypobranchial gland; nep, nephridium; nr, nerve ring; od, odontophore with radula; oe, esophagus; os, osphradium; p, penis; pr, proboscis; prp, propodium; r, rectum; s, siphon; sg, salivary gland; tmg, tubular part of mid-gut gland.