Terebra assu Simone, 2012

Simone, Luiz Ricardo L. & Cunha, Carlo M., 2012, Taxonomic study on the molluscs collected in Marion-Dufresne expedition (MD 55) to SE Brazil: Xenophoridae, Cypraeoidea, mitriforms and Terebridae (Caenogastropoda), Zoosystema 34 (4), pp. 745-781 : 772-774

publication ID

https://doi.org/ 10.5252/z2012n4a6

publication LSID

lsid:zoobank.org:pub:857CAD31-66E1-4CEE-AB4D-CCD64541D0EF

persistent identifier

https://treatment.plazi.org/id/03AA8317-C653-0D49-FC88-994ECE890F44

treatment provided by

Felipe

scientific name

Terebra assu Simone
status

n. sp.

Terebra assu Simone n. sp.

( Fig. 10 View FIG A-E)

TYPE MATERIAL. — Holotype: Brazil, Espírito Santo, off Conceição da Barra, continental slope of Abrolhos , 18°59’S, 37°50’W, 295 m depth, MNHN 25244 View Materials ( Fig. 10A View FIG , C-E) ( MD55 , stn DC75 , Bouchet, Leal & Métivier coll., 27.V.1987). GoogleMaps

Paratypes:same data as holotype, MNHN 25242, 1 shell, MZSP 102598, 1 shell ( Fig. 10B View FIG ).

TYPE LOCALITY. — Brazil, Espírito Santo, off Conceição da Barra, continental slope of Abrolhos, 18°59’S, 37°50’W, 295 m depth ( MD 55, stn DC 75).

DISTRIBUTION. — Known only for the type locality.

ETYMOLOGY. — The specific epithet refers to the elongation of the shell, from the Tupi native language “açu” (transliterated to assu), meaning elongated, slender.

DIAGNOSIS. — Narrow shell with pale yellowish colour. Protoconch paucispiral, with one whorl. Sculpture reticulate strong in 4-5 first teleoconch whorls, becoming weaker, with predominance of axial threads in remaining whorls. Subsutural ridge somewhat prominent.

DESCRIPTION

Shell: up to 9.8 mm long, width c. ∕₅ of length, spire angle c. 13°. Colour predominantly white, with yellowish band in middle level of each whorl, comprising c. 80% of each whorl area ( Fig. 10A, B View FIG ); band margins unclear. Protoconch simple, smooth, of one whorl ( Fig. 10D, E View FIG ); width c. 35% of maximum teleoconch width; length c. 16% of shell length. Limit between protoconch and teleoconch indistinct ( Fig. 10E View FIG ). Teleoconch with up to 10 whorls; profile weakly convex, suture clear but shallow. Sculpture of first teleoconch whorls with only strong axial threads, c. 10 per whorl, each thread smooth, with upper node, between both threads length equivalent to double their width; in third whorl spiral threads gradually appearing, becoming stronger in following whorls, equally predominating as axial threads; after sixth teleoconch whorl sculpture becoming weak, spiral threads almost disappearing, axial threads somewhat predominating, space between axial threads 3-4 times wider than threads; four spiral threads and 7-8 axial threads in penultimate whorl. Subsutural thread somewhat prominent, being c. 50% larger than remaining threads; in first whorls mainly marked by nodes of axial threads, after 3-4 teleoconch whorls becoming similar to remaining threads. After sixth teleoconch whorl sculpture gradually becoming weaker than preceding whorls, both spiral and axial threads. In last whorl, c. 15 axial threads in penultimate whorl, with interspaces c. 3 times wider than threads width; 5-6 spiral threads in penultimate whorl, being inferior threads narrower and closer with each other than upper threads; subsutural thread of similar size as remaining threads. Sculpture of peri-umbilical area composed of 7-8 spiral liration in upper half, and series of low transverse scales in inferior half ( Fig. 10A, C View FIG ). Aperture orthocline, oval, about twice longer than wide. Outer lip thick, simple, with blunt notches corresponding to spiral sculpture. Inner lip with weak callus; parietal region in upper third, marked by abrupt curve in c. 40°; siphonal region in inferior ⅔, somewhat straight and vertical, except for region close to anterior end, with bright curve to left ( Fig. 10B, C View FIG ). Canal short, slightly curved to left.

MEASUREMENTS (in mm). — Holotype: 9.8 × 2.0; paratype MZSP 102598 View Materials : 8.3 × 1.8; paratype MNHN 25242 View Materials : 5.4 × 1.6.

HABITAT. — Sandy-mud bottoms, 295 m depth.

REMARKS

Terebra assu Simone n. sp. differs from the other closely-related species in being small (smaller than 10 mm, while others usually reach 20 mm, such as T. leptapsis and T. crassireticula – Fig. 11 View FIG I-L) in an equivalent number of whorls; with a pale yellowish pigmentation in middle region of each whorl (most species are pure white – T. crassireticula , T. alagoensis – Figs 10 View FIG F-I; 11A-D, L; uniform pale brown – T.doellojuradoi , T. leptapsis – Fig.11 View FIG E-K; but it is somewhat similar to T. simonei Lima,Tenório & Barros, 2007 : figs 1-6); and by the weaker sculpture of the last whorls both in number and in size. This last character produces a feeble reticulate sculpture on the last whorls, in such the axial threads surrounds 15 on the penultimate whorl, while the remaining species in the T. doellojuradoi complex normally possess over 25. The protoconch is proportionally broader than the other closer species. The aperture is more elongated and narrow ( Fig. 10 View FIG A-C) than those of the other close species, except for T. crassireticula ( Fig. 11L View FIG ). The subsutural spiral thread is only more developed in the first teleoconch whorls, resembling T. alagoensis ( Figs 10 View FIG F-I; 11A-D); the first whorls of T. assu Simone n. sp. can be distinguished from those of T. alagoensis in having more elongated whorls with a more concave profile.

Terebra alagoensis Lima, Tenório & Barros, 2007 ( Fig. 10 View FIG F-I; 11A-D)

Terebra alagoensis Lima, Tenório & Barros, 2007: 66 , figs 13-17. — Rios 2009: 358, fig.937. — Rosenberg 2009.

TYPE MATERIAL ( EXAMINED). — Holotype: Brazil, continental slope off Alagoas, 10°05’57’’S, 35°46’24’’W, 720 m, MZSP 84238 View Materials ( Fig. 11 View FIG A-D) ( R / V Natureza, stn D-29, 28.X.2000). GoogleMaps

OTHER MATERIAL EXAMINED. — Brazil, Espírito Santo, continental slope of Abrolhos, off Rio Doce, Abrolhos bank, 19°34’S, 38°55’W, 340-360 m depth, MNHN, 10 shells, MZSP 102613, 2 shells ( Figs 10F, H, I View FIG ) ( MD 55, stn CB 92, Bouchet, Leal & Métivier coll., 29. V.1987). — East of São Tomé Cape, 21°31’S, 40°08’W, 295-300 m depth, MNHN, 10 shells, MZSP 102607, 3 shells ( Fig. 10G View FIG ) ( MD 55, stn CB 96, 31. V.1987).

TYPE LOCALITY. — Brazil, continental slope off Alagoas, 10°05’57’’S, 35°46’24’’W, 720 m ( R / V Natureza, stn D-29).

DISTRIBUTION. — From Alagoas to Espírito Santo.

DESCRIPTION

See Lima et al. (2007: 66).

MEASUREMENTS (in mm). — Holotype: 10.5 × 2.8; MNHN (stn CB92) (1): 4.9 × 1.6; MZSP 102607 (1): 4.1 × 1.4.

HABITAT. — Sandy-mud, 340-720 m depth.

REMARKS

Terebra alagoensis is very distinct from the remaining T. doellojuradoi complex by its large subsutural spiral thread, producing almost a shoulder. The whorls have their periphery almost flat and vertical, giving it a scalariform effect in the spire. The MD55 material ( Fig. 10 View FIG F-I) is constituted of a single lot with 13 specimens, all of which considerably younger than the holotype ( Fig. 11 View FIG A-D); the largest specimen is 4.9 mm long; although the shell characters clearly allowed the identification. This new record considerably expands the geographic distribution of this species at almost 800 km southward. However, despite the distance, the environment and depth are equivalent.

Another interesting feature of Terebra alagoensis is the relatively wide protoconch ( Figs 10H, I View FIG ; 11B, C View FIG ), comprising a wide portion of the shell apex ( Figs 10F, G View FIG ; 11A View FIG ). The transition with teleoconch is not so clear ( Figs 10I View FIG ; 11C View FIG ), and the first teleoconch whorl is marked by pure axial, lyrate sculpture ( Figs 10 View FIG G-I; 11B, C). The spiral sculpture gradually appears after the first teleoconch whorl. The aperture of Terebra alagoensis is marked by a pair of oblique folds in the middle level of the inner lip ( Fig. 11A, D View FIG ), which are also evident, but lower, in the younger specimens ( Fig. 10F, G View FIG ). This is not a normal pattern for the T. doellojuradoi complex.

MNHN

Museum National d'Histoire Naturelle

MZSP

Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo

MD

Museum Donaueschingen

R

Departamento de Geologia, Universidad de Chile

V

Royal British Columbia Museum - Herbarium

CB

The CB Rhizobium Collection

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Neogastropoda

Family

Terebridae

Genus

Terebra

Loc

Terebra assu Simone

Simone, Luiz Ricardo L. & Cunha, Carlo M. 2012
2012
Loc

Terebra alagoensis Lima, Tenório & Barros, 2007: 66

RIOS E. C. 2009: 358
LIMA S. F. B. & TENORIO D. O. & BARROS J. C. N. 2007: 66
2007