Terebra sterigmoides, Simone & Gracia, 2006

Simone, Luiz Ricardo L. & C., Adriana Gracia, 2006, Two New Species Of Terebra (Gastropoda, Conoidea) From Colombia, Papéis Avulsos de Zoologia 46 (11), pp. 125-132 : 126-131

Terebra sterigmoides new species

( Figs. 16-25 )

Terebra (Strioterebum) protexta: Díaz-Merlano & Puyana- Hegenus, 1994: 217 (pl. 66, fig. 858) (non Conrad, 1846).

Types – Holotype INV MOL 2388. Paratypes: Sucre; off San Bernardo Islands, 9°48´50.1”N 76°10´24.2”W, 94 m depth, INV MOL5482, 3 shells (Sta. D18, 29/iv/2005); 9°48´05.1”N 76°11´08.0”W, 95 m depth, INV MOL5481, 5 shells (Sta. D19, 29/iv/2005); 9°47´21.8”N 76°11´52.2”W, 98 m depth, INV MOL5480, 3 shells (Sta. D20, 29/iv/2005); 9°46´36.9”N 76°12´48.1”W, 102 m depth, INV MOL5479, 3 shells (Sta. D21, 29/iv / 2005).

Type locality – COLOMBIA. La Guajira; off Manaure , 11°53’05”N 72°36’39”W, 21 m depth (sta. E98, 16 /iii/2001).

Diagnosis

Protoconch with two whorls. Teleoconch sculptured by narrow axial and weak spiral ribs, axial ribs stronger; presence of subsutural furrow; about 26 axial and 6 spiral ribs in penultimate whorl. Subsutural set of nodes well-marked. A pair of middle columellar folds.

Description

Shell ( Figs. 16-25 ) – Long, slender, turriform, small size (about 14 mm), up to 16 convex whorls; color whitish to pale beige. Spire angle approximately of 24°. Protoconch ( Figs. 19 , 24 ) with two similar sized whorls, convex, smooth; somewhat cylindrical; transition with teleoconch clear. Sculpture of firsts teleoconch whorls ( Figs. 9, 10 , 24 ) narrow axial ribs (lyrate), each one lacking nodes; spiral ribs gradually appearing in third teleoconch whorl ( Fig. 25 ), 6 in penultimate whorl, with about 1/3 of the width of axial ribs; practically no node at intersection of spiral and axial ribs ( Figs. 22, 23, 25 ); subsutural nodes clearly larger than others, marked by spiral shallow furrow; about 26 axial ribs in penultimate whorl; interval between axial ribs about same as rib width. Aperture simple ( Figs. 20 , 22 ); outer lip edged; inner lip smooth, sigmoid, possessing pair of oblique, low folds located in middle region, inferior fold continuous with inner edge of canal ( Figs. 18, 20 , 22 ). Canal short, somewhat widely opened, weakly curved.

Measurements (in mm) – Holotype INV MOL2388, 13.7 by 3.8; INV MOL5479 (3 shells): length 24.23; 22.49; 17.91 respectively; INV MOL5480 (3 shells): length 11.46; 8.91; 7.75; 5.44 resp.; INV MOL5481 (5 shells): length 10.06; 7.53; 6.61; 6.52; 4.07 resp.; INV MOL5482 (4 shells): length 8.84; 7.00; 5.58; 4.72 resp.

Distribution – Known to type locality.

Habitat – Continental shelf soft bottoms, from 20 to 102 m depth (only shells).

Material examined – Types.

Etymology – The specific name refers to similarity with Brazilian species Terebra sterigma Simone, 1999 . The termination “in form of ” (oides) is added.

Figures

Figuras 16-21. Terebra sterigmoides holotype: 16) frontal view; 17) dorsal view; 18) frontal view in SEM; 19) apical region in SEM; 20) detail of aperture, frontal-slightly oblique view; 21) detail of last whorl, dorsal view. Length = 13.7 mm.

Figuras 22-27. Terebra spp shells: 22-25) Terebra sterigmoides paratypes; 22-23) INV MOL5479, frontal and dorsal views, length = 24.23 mm; 24) INV MOL5480, SEM, detail of protoconch and first teleoconch whorl in profile, scale = 0.1 mm; 25) same, detail of middle region of spire, scale = 1 mm; 26-27) T. cobombiensis holotype, SEM; 26) shell apex in profile, scale = 0.1 mm; 27) detail of middle region of spire, scale = 1 mm.

Figuras 7-15. Terebra colombiensis holotype and paratypes: 7-13) Holotype; 7) dorsal view; 8) frontal view; 9) frontal view in SEM; total length = 16.6 mm; 10) detail of apical region of shell, SEM; 11) detail of middle region of shell, showing sculpture; 12) detail of penultimate whorl, frontal view; 13) same, SEM, slightly oblique view; 14) paratype INV MOL 1962, frontal view, length = 15.66 mm; 15) paratype INV MOL 3427, length = 12 mm.