Eratoena gourgueti, Fehse, 2010

Fehse, Dirk, 2010, Contributions to the knowledge of the Eratoidae IV. A new species from Tuamotu, French Polynesia, add _ journal _ name _ here 33 (1), pp. 13-18 : 14-17

Eratoena gourgueti spec. nov.

Pl. 1, Figs 1 , 2; Pl. 2, Fig. 1

Types. Empty shells were dived in depths of 5-35 m in rubble at all mentioned localities. – Holotype: Off barrier reef of the atoll of Makemo, Tuamotu, French Polynesia; length: 4.0 mm; width: 2.3 mm; height: 1.8 mm; LT 30; CT 21 ( ZSM, coll. No. 20091000). — Paratypes: No. 1: barrier reef of the atoll of Makemo, Tuamotu, French Polynesia; length: 3.7 mm; width: 2.1 mm; height: 1.6 mm; LT –; CT – subadult ( DFB, No. 9233); No. 2: Off Motu Otepipi, Rangiroa, Tuamotu, French Polynesia; length: 3.7 mm; width: 2.0 mm; height: 1.5 mm; LT 25; CT 19 ( DFB, No. 9234-1); No. 3: Off Motu Otepipi, Rangiroa, Tuamotu, French Polynesia; length: 3.1 mm; width: 1.8 mm; height: 1.4 mm; LT –; CT – subadult ( DFB, No. 9234-2); No. 4: Off Motu Otepipi, Rangiroa, Tuamotu, French Polynesia; length: 3.3 mm; width: 2.0 mm; height: 1.6 mm; LT 22; CT 18 ( JLT). Further paratypes in collection DFB, J. Letourneux and R. Gourguet .

Description

Shell small, fragile, slender, elongated, almost cylindrical with a short, conical spire. Protoconch consisting of 1-1 ½ whorls with a very small nucleus. Suture indistinct and only visible through the translucent shell. Junction with teleoconch not clearly defined. Teleoconch comprising 2 ½ -3 flat-sided whorls. Body whorl about 95 % of total height, slender, elongated, almost cylindrical, with the maximum diameter almost centrally. Dorsum finely granulated, rounded, with an incised dorsal sulcus and not constricted behind the anterior extremity. Aperture very narrow and straight, 85-90 % of total height. Labrum weakly thickened, almost straight, bearing up to 30 fine and equal denticles on the inner margin, which do extend onto the lip as very fine folds. Siphonal canal short, rounded and straight.Columella smooth, slightly sinuous, bordered internally by a weak carinal ridge. The ridge is slightly stronger in the fossular area and slightly protruding. Parietal lip roundly thickened, bearing up to 21 weak denticles. The most anterior 2-4 denticles are developed into Plate 1.

1. Eratoena gourgueti spec. nov., Holotype, ZSM, coll. No. 20091000.

2. Eratoena gourgueti spec. nov., Paratype 1, DFB, coll. No. 9233, subadult. Off Makemo, Tuamotu, on barrier reef. 3. Eratoena schmeltziana (Crosse, 1867) , DFB, coll. No. 9232. Off Tiarei, Tahiti; collected on reef .

Plate 2.

1. Eratoena gourgueti spec. nov., Paratype 2, DFB, No. 9234-1, granulated variety, Off Motu Otepipi, Rangiroa, Tuamotu .

2. Eratoena schmeltziana (Crosse, 1867) , DFB, coll. No. 5445. Off Apdoiti, Raiatea Isl. , Society Isls, French Polynesia, at 5-10 m in rubble .

3. Eratoena schmeltziana (Crosse, 1867) , DFB, coll. No. 6093. Off Miri-Miri, Raiatea Isl. , Society Isls, French Polynesia; dredged at 10-12 m in rubble sand .

unusually short folds, which run obliquely across the ventrum. Fossula marked by a weak concavity. Terminal ridge simple and strong running along the border of the siphonal canal.

Shell colour translucent white with a light red clouding and a broad transverse white band on the dorsum. Anterior labral tip red, anterior ventral tip very indistinct red.

Variation: The dorsal sulcus is not developed in juvenile specimens and the shell is smooth. Subadult specimens are covered with more callous where the sulcus is already incised and the granulation slightly developed. Matured shells show a deeply incised sulcus, the granules and the dentition are fully developed. The number of labral teeth varies between 22 and 30 and the number of columellar teeth between 18 and 21. The ratio width to length is in average 58 % but varies between 55 % and 61 %.

No information is available on external morphology and radula.

Etymology. In honour to Robert Gourguet, Tuamotu, who provided sufficient material to describe this taxon.

Distribution. The new species is confirmed by paratypes in the author’ s collection besides the type locality also from Rangiroa, Tuamotu; Pt. Venus, Tahiti; Marpi, Saipan and Periki, Jawa, Indonesia.

Figures

Fig. 1. Comparison of the shell morphology of E. gourgueti spec. nov. and its congener E. schmeltziana.