Turricostellaria ovir, Simone & Cunha, 2012
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publication ID |
https://doi.org/ 10.5252/z2012n4a6 |
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publication LSID |
lsid:zoobank.org:pub:857CAD31-66E1-4CEE-AB4D-CCD64541D0EF |
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persistent identifier |
https://treatment.plazi.org/id/03AA8317-C647-0D45-FCB5-9E76CE3409E3 |
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treatment provided by |
Felipe |
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scientific name |
Turricostellaria ovir |
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sp. nov. |
Turricostellaria ovir View in CoL n. sp.
( Fig. 6 View FIG A-D)
TYPE MATERIAL. — Holotype: Brazil, Espírito Santo, off Itaúnas, continental slope of Abrolhos, 18°58’S, 37°48’W, 1200 m depth, MNHN 25237 ( Fig. 6A, B View FIG ) ( MD 55, stn DC 78, Bouchet, Leal & Métivier coll., 27. V.1987). Paratypes: same data as holotype, MZSP 102860, 1 shell ( Fig. 6C, D View FIG ). — Off Conceição da Barra, 18°59’S, 37°47’W, 1540-1550 m depth, MZSP 102860, 1 shell ( Fig. 6C, D View FIG ) (stn CB 70, 26. V.1987).
TYPE LOCALITY. — Brazil, Espírito Santo, off Itaúnas, continental slope of Abrolhos, 18°58’S, 37°48’W, 1200 m depth ( MD 55, stn DC 78).
DISTRIBUTION. — Espírito Santo continental slope.
ETYMOLOGY. — The specific epithet is derived from the native Parintintin language, from “ovir”, meaning sharp pointed, arrow-like ( Betts 1981), an allusion to the outline of the shell shape.
DIAGNOSIS. — Shell up to 10 mm, elongated (length c. 3 times width). Sculpture axial, strong, slightly prosocline; shoulder absent. Protoconch blunt, mammillate, of two whorls. Aperture c. ⅓ shell length. Canal narrow, relatively elongated.
DESCRIPTION
Shell:size up to 10 mm, outline somewhat turriform; width c. 35% of length. Colour uniform white ( Fig. 6 View FIG A-C); surface opaque. Protoconch blunt, mammillate, comprising c. 6% of shell length and c. 16% of shell width; about two rounded, smooth, glossy whorls; suture shallow unclear ( Fig. 6D View FIG ); transition with teleoconch unclear. Spire c. 55% of shell length; spire angle c. 30°. Teleoconch up to 6.5 whorls; each whorl lacking shoulder in last whorls ( Fig. 6A, B View FIG ), and having shallow shoulder located below upper quarter of each whorl; remaining profile almost straight. Sculpture strong, uniform axial threads, slightly prosocline (angle c. 10° in relation to shell longitudinal axis), from suture to suture; small node on shoulder in first teleoconch whorls ( Fig. 6C, D View FIG ); c. 12 in penultimate whorl; interspaces of axial threads roundly concave, as wide as threads. Ventral region of body whorl lacking spiral threads in anterior third ( Fig. 6A View FIG ). Aperture elliptic, almost vertical; comprising c. 30% of shell length and c. 38% of shell width. Outer lip simple, rounded, lacking folds ( Fig. 6A, B View FIG ). Inner lip weakly concave, callus shallow, upper third c. 30° in relation to longitudinal shell axis; four oblique folds uniformly distributed in middle region, comprising c. 70% of inner lip area; upper folds larger, diminishing up to inconspicuous fourth fold flanking canal ( Fig. 6A, C View FIG ). Canal narrow, pointed, projected forwards along c. 13% of shell length; with c. 30% of aperture width. Dorsal surface of canal with pair of oblique, low folds as continuation of two upper columellar folds ( Fig. 6B View FIG ). No umbilicus.
MEASUREMENTS (inmm). — Holotype: 9.9 × 3.6; paratype MZSP 102860 View Materials : 5.2 × 2.5.
HABITAT. — Sandy-mud bottoms, 1200-1550 m depth.
DISCUSSION ON TURRICOSTELLARIA SPECIES
The genus Turricostellaria was coined to hold two Venezuelan, deep-water species with “tabulate whorls and scalariform appearance” ( Petuch 1987: 108), resembling a turrid. Despite some authors have considered it synonym of Vexillum (e.g., Rosenberg 2010), it appears to be sufficiently distinct to be considered valid. It encompasses, beyond the two originally described species, at least another four species described herein, representing a deep-water taxon with turriform-like species, lacking spiral sculpture.
Despite the protoconch was never mentioned in the original description of Turricostellaria , neither afterwards, the species described here show that the structure can divide the species of the genus into two groups: one with paucispiral protoconch ( T. amphissa n. sp. and T. ovir n. sp. – Figs 5 View FIG B-D; 6C) and the other with multispiral protoconch ( T. jukyry n. sp. and T. apyrahi n. sp. – Fig. 5I, N View FIG ). There is no indication of the protoconch of T. leonardhilli Petuch, 1987 and T. lindae Petuch, 1987 ; in the figures the structure appears eroded or paucispiral. The protoconch of T. amphissa n. sp. is the shortest and widest, with a flattened suture; that of T. ovir n. sp. is slightly longer and pointed, with suture slightly clearer. The protoconch of T. jukyry n. sp. is the longest, bearing four whorls with deep suture; that of T. apyrahi n. sp. has three whorls and is blunter.Additionally, those multispiral protoconch-bearing species have it in a pale brown colour, distinct from the remaining whitish colour of the teleoconch; this does not happen in the species with paucispiral protoconch.
Turricostellaria amphissa n. sp. is the shortest and most inflated of the genus; it is also the smallest (c. 5 mm) and has the thinnest shell walls, being translucent. These are the main distinctions of the species. Turricostellaria ovir n. sp. is the most elongated and sharpest of the genus, in this aspect it resembles T. lindae , differing in lacking a developed shoulder and by the whorls much more elongated. The most difficult distinction is between T. jukyry n. sp. and T. apyrahi n. sp. Beyond the different protoconch mentioned above, T. jukyry n. sp. has the shoulder more distinct, mainly in the first teleoconch whorls ( Fig. 5G, K View FIG ), and the sculpture in this region is more developed and uniform than that of T. apyrahi n. sp. The colour of T. apyrahi n. sp. is more uniform, while that of T. jukyry n. sp. is in yellow bands. The body whorl of T. apyrahi n. sp. tends to be wider than expected for a uniform spiral growth ( Fig. 5Q, R View FIG ), which does not happen in T. jukyry n. sp. The aperture of T. jukyry n. sp. is slightly shorter and more rounded, and the upper region of inner lip slightly more horizontal than that of T. apyrahi n. sp. The axial sculpture is also distinctive, as that of T. jukyry n. sp. tends to be more uniform and strong ( Fig. 5H, K View FIG ) than that of T. apyrahi n. sp., which lacks the axial sculpture in the last whorls ( Fig. 5L, Q View FIG ).
Turricostellaria apyrahi n. sp. is the most similar to the Venezuelan T. leonardhilli ; it differs in having a more elongated outline and whorls, axial sculpture more developed, aperture slightly ampler, body whorl wider, and, mainly, the multispiral and pointed protoconch. The species also resembles Latiromitra bairdii (Dall, 1889) , from North Carolina (965 m depth); it differs in being shorter and wider, in having the aperture wider and longer, and the sculpture more developed. Turricostellaria ovir n. sp. still differs from T. leonardhilli in being more elongated, in having a small subsutural shoulder, more straight whorls profile, narrower body whorl and axial sculpture much more developed.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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