Teretia neocaledonica, Morassi, Mauro & Bonfitto, Antonio, 2015

Morassi, Mauro & Bonfitto, Antonio, 2015, New Indo-Pacific species of the genus Teretia Norman, 1888 (Gastropoda: Raphitomidae), Zootaxa 3911 (4), pp. 560-570 : 562

Teretia neocaledonica sp. nov.

Figures 1.A–J

Type material: Holotype ( MNHN IM- 2000-28374) and 22 paratypes (21 paratypes MNHN IM- 2000-28376; one paratype MZB 60095)

Type locality: South of New Caledonia, Bank Eponge (mont 8), 24°55S 168°22E, 502–532 m [N/ O “Alis” SMIB 8 stn DW146-147].

Material examined: South of New Caledonia: Bank Eponge (mont 8), 24°55S 168°22E, 502–532 m [N/ O “Alis” SMIB 8 stn DW146-147] (23 dd, holotype and 22 paratypes); Bank Eponge (mont 8), 24°55.20'S 168°21.73'E, 514–522 m [N/ O “Alis” SMIB 8 stn DW146] 27 January 1993 (1 dd). Coral Sea, Bank CAPEL: 24° 44.83 S 159° 41.00 E, 285 m [N/ O “Coriolis” MUSORSTOM 5 stn DW 274], Bouchet, Metivier& Richer coll. 0 9 October 1986 (1 dd). New Caledonia, Loyalty Ridge: 24°45,55'S 170°07,40' E, 850–855 m [N/ O “Alis” BATHUS 3 stn DW 780], Bouchet, Richer &Warén coll. 24 November 1993 (1 dd); 23°47,50'S 169°48,75'E, 731–751 m [N/ O “Alis” BATHUS3 stn DW 793], Bouchet, Richer &Warén coll. 26.11.1993 (1 dd); 23°35,12' S 169°36,73' E, 655 m [N/ O “Alis” BATHUS 3 stn DW 800], Bouchet, Richer &Warén coll. 26 November 1993 (1 dd); 23°39,39'S 167°58,94'E, 650–730 m [N/ O “Alis” BATHUS3 stn DW 809], 27 December 1993 (1 dd).

Description. Shell ( Figs. 1.A–D ) fusiform (b/l 0.41; a/l 0.33) with high spire, strongly excavated base and relatively long anterior canal. Teleoconch up to about 4¾ whorls (four in most specimens) with shallowly impressed, linear suture. Subsutural ramp wide, shallowly concave. Earlier two teleoconch whorls with a prominent peripheral cord below mid- height of the whorl and two closely spaced weak cords bordering abapical part of subsutural ramp. On third whorl the adapical cord on subsutural ramp becomes bisected and a second main cord develops at level of abapical suture ( Figs. 1.E–F ). Last whorl with a third main cord and additional weak cords: one on abapical part of subsutural ramp and 1–2 in each interspace between main spiral cords. Last whorl with 26 spiral cords on base and rostrum. Subsutural ramp with two spiral threads bordering adapical suture. Teleoconch whorls sculptured by fine axial growth lines forming weak, widely spaced, arcuate plicules on subsutural ramp, rendering somewhat nodulous the two spiral threads bordering adapical suture ( Fig. 1.E ). Under SEM ( Figs. 1.E–G ), surface is seen to be covered by a sculpture of microgranules. Aperture lanceolate, outer lip thin. Anal sinus very deep, narrow, asymmetrical, with its deepest point on sutural ramp ( Fig. 1.D ). Protoconch ( Figs. 1.H–J ) tall, narrowly conical of 3½–4 whorls; first whorl tilted with microgranules arranged in spiral rows, subsequent whorls with diagonally cancellate sculpture terminating a short distance above abapical suture where fine slightly prosocline riblets occur. Maximum diameter about 0.48 mm. Shell yellowish-white to white with a yellowish-brown band on periphery of whorls: weak to absent on first whorl, distinct on penultimate and last whorls, and (in some specimens) also at level of limit base-rostrum. Some specimens with few weak, light brown, subsutural blotches on last whorl. Protoconch brown. Dimensions: Holotype 5.9 x 2.4 mm, aperture height 2.6 mm.

Remarks. Teretia neocaledonica sp. nov. resembles the Miocene-Pliocene T. turritelloides ( Bellardi, 1847) in shape and disposition of spiral cords but differs from the latter in details of protoconch and teleoconch sculpture. More in detail, Teretia neocaledonica sp. nov. has slightly fewer protoconch whorls than T. turritelloides (3.5–4 versus 4–4.5) with a different sculpture; in the new species the axial riblets strongly decussate on periphery of each protoconch whorl, particularly on last whorl, while in T. turritelloides decussation occurs on whorl surface except for a narrow area near adapical suture (see Brunetti & Vecchi, 2003: plate 3, fig. 3). Furthermore, judging from the syntype of T. turritelloides from the Pliocene of Colli Astesi, figured by Ferrero Mortara et al. (1981: pl. 18, fig. 6a–6b), the fossil species has a secondary sculpture more prominent than T. neocaledonica . The Italian Pliocene Teretia elegantissima (Foresti, 1868) differs distinctly from the new species in having a much more prominent peripheral keel formed by numerous (4–6) closely spaced spiral cords (fig. 3.G).

Etymology. Neocaledonica = alluding to the fact that the type material was dredged off New Caledonia.

Figures

FIGURE 1. A – J. Teretia neocaledonica sp. nov. A. Holotype (MNHN IM- 2000 - 28374), New Caledonia, Cruise SMIB 8, stn DW 146 - 147, 5.9 x 2.4 mm. B – J. Paratype (MZB 60095), New Caledonia, Cruise SMIB 8, stn DW 146 - 147. B. Shell, 4.9 x 2.1 mm. C – D. Coated specimen, frontal and lateral view, scale bar 2 mm. E. Penultimate whorl, scale bar 500 µm. F – G. Microsculpture of penultimate whorl, scale bar 100 µm. H – I. Protoconch, scale bar 500 µm. J. Details of protoconch 1, scale bar 100 µm. L – T. Teretia sysoevi sp. nov. L – M. Holotype (MNHN IM- 2000 - 28375), South-West Pacific, Cruise MUSORSTOM 7, stn DW 507, 5.8 x 2.3 mm. N. Paratype 1 (MNHN IM- 2000 - 28377), New Caledonia, Cruise BATHUS 3, stn DW 786, 7.2 x 2.8 mm. O – T. Paratype 2 (MZB 60096), New Caledonia, Cruise MUSORSTOM 4, stn DC 168. O. Shell, 7.5 x 2.9 mm scale bar 1 mm. P. Penultimate whorl, scale bar 600 µm. Q. Microsculpture of penultimate whorl, scale bar 200 µm. R. Microsculpture of penultimate whorl, scale bar 80 µm. S – T. Protoconch, scale bar 200 µm.