Marshallora ostenta Rolan & Fernandez-Garces 2008
Creators: name: Fernandes, Maurício Romulo
name: Pimenta, Alexandre Dias
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Triphoridae
Marshallora
Marshallora ostenta

description: Marshallora ostenta Rolán & Fernández-Garcés, 2008
Figs 7–8, 23L, 54, 83
Marshallora ostenta Rolán & Fernández-Garcés, 2008: 94, figs 7A–N, 8E–F.
Marshallora ostenta – Lee 2009: 89.
Material examined
Holotype
CUBA • Cienfuegos Bay; MNCN 15.05/47055.
Paratypes
See Rolán & Fernández-Garcés (2008).
Other material
BRAZIL – North Brazil • 11 specs; REVIZEE-Norte III st. 176; UFMA * • 1 spec.; REVIZEE-Norte III st. 192; UFMA*. – Amapá • 1 spec.; 03º58′43″ N, 49º33′24″ W; 2001; MNRJ 32570 * • 1 spec.; AMASSEDS st. 4134; MORG 43335 • 1 spec.; AMASSEDS st. 3210; MNRJ 33801 *. – Rio Grande do Norte • 1 spec.; BPot 1-MR31; MNRJ 31536 * • 1 spec.; BPot 1-MR41; MNRJ 31538 * • 1 spec.; BPot 2-MR32; MNRJ 31657 * • 2 specs; BPot 2-MR41; MNRJ 31540 * • 1 spec.; BPot 2-MR45; MNRJ 31541 *. – Sergipe • 1 spec.; Petro /UFS st. E5-A1; with soft part preservation; UFS • 1 spec.; Petro/UFS st. 15.3; UFS • 1 spec.; Petro/UFS st. 18.1; UFS. – Bahia • 4 specs; Baía de Todos os Santos; May 1997; MNRJ 34430 * • 1 spec.; Parcel Paredes, Alcobaça; depth 0–3 m; 8 Jan. 2000; P.J. Souza and E. Gonçalves leg.; MZSP 56305 *. – Espírito Santo • 1 spec.; REVIZEE-Central C1-VV24; MORG 40378 • 2 specs; REVIZEE-Central C1-VV24; MORG 52253 • 3 specs; REVIZEE-Central C1-VV31; IBUFRJ 19484 • 1 spec.; REVIZEE-Central C1-C65; MORG 39090 * • 1 spec.; 19º25′08″ S, 39º15′59″ W; depth 46 m; Oct. 2003; MNRJ 31169 * • 1 spec.; 19º25′37″ S, 39º22′22″ W; depth 43 m; Oct. 2003; MNRJ 30750 * • 1 spec.; REVIZEE-Central C1-VV38; IBUFRJ 19614 • 1 spec.; REVIZEE-Central C6-R2#1-1; IBUFRJ 19506 • 1 spec.; 20º14′ S, 40º12′ W; Jun. 2008; MNRJ 32659 * • 1 spec.; 20º42′00″ S, 40º24′28″ W, Ilha Escalvada; depth 10–15 m; Jan. 2013; W. Vieira leg.; MNRJ 34026 * • 2 specs; 20º42′ S, 40º06′ W; depth 43 m; 27 Aug. 1979; IBUFRJ 19551 • 6 specs; 20º47′ S, 40º34′ W; Nov. 2007; MNRJ 32412 * • 1 spec.; 20º47′ S, 40º34′ W; Sep. 2007 – Oct. 2008; MNRJ 17227 * • 1 spec.; 20º47′ S, 40º34′ W; Sep. 2007 – Oct. 2008; MNRJ 30838 * • 1 spec.; 20º47′ S, 40º34′ W; Sep. 2007 – Oct. 2008; MNRJ 31017 * • 1 spec.; 20º47′ S, 40º34′ W; Sep. 2007 – Oct. 2008; MNRJ 31029 * • 1 spec.; 20º47′ S, 40º34′ W; Sep. 2007 – Oct. 2008; MNRJ 31139 * • 1 spec.; 20º47′ S, 40º34′ W; Mar. 2010; MNRJ 31047 * • 2spec; 20º47′ S, 40º34′ W; Mar. 2010; MNRJ 31087 * • 1 spec.; 20º47′ S, 40º34′ W; Mar. 2010; MNRJ 31092 * – Rio de Janeiro • 2 specs; HAB 13-H2; MNRJ 18588 * • 1 spec.; HAB 16- G1; MNRJ 18623 * • 1 spec.; REVIZEE-Central C1-D1-2; IBUFRJ 19532 • 1 spec.; REVIZEE-Central C1-D3; IBUFRJ 12881.
UNITED STATES OF AMERICA – Georgia • 1 spec.; 30º54′18″ N, 80º36′12″ W; depth 35 m; 4 Sep. 1980; R/V Bagby leg.; with soft part preservation; USNM 848771.
Description
Shell sinistral, elongated, cyrtoconoid to slightly ovoid, moderately convex profile, up to 4.4 mm long, 1.4 mm wide, length/width ratio 2.4 to 3.4. Protoconch multispiral, conical, 0.47–0.55 mm long, 0.40– 0.45 mm wide, 4.75–5.25 convex whorls; embryonic shell dome-shaped, covered by small granules in its abapical portion; larval shell with two spiral cords strengthening through first whorl, soon becoming distinct, but adapical one disappears about one whorl after its emergence or as late as at last whorl; adapical cord can be much weaker than abapical one; cords respectively situated at ~39% and 60%–69% of penultimate whorl height; ~27 nearly rectilinear to slightly sigmoid axial ribs. Teleoconch with up to nine whorls; two spiral cords (adapical and abapical) at beginning, abapical one continuous to that of protoconch; median spiral cord emerges in fourth or fifth whorl (rarely in sixth whorl), reaching same size as other cords after 0.5 to 1.5 whorl; on body whorl, spiral cords are 0.9–1.5 × as wide as distance between them; 20–23 nearly orthocline axial ribs at fifth whorl; rounded nodules, with moderately large to medium size; suture distinct, well developed, with small sutural cord; slightly wavy to nearly smooth subperipheral cord, two smooth basal cords; no supranumerical cords; ovate aperture, 0.58–0.79 mm long, 0.45–0.61 mm wide, length/width ratio 1.2–1.3; anterior canal short, open or partly closed by the projection of outer lip, 0.18–0.31 mm long, 0.17–0.25 mm wide, length/width ratio 0.9–1.4; posterior canal as small sinus, 0.07–0.12 mm long. Protoconch light-brown to golden, embryonic shell whitish; teleoconch with faint cream to light brown background, one or two initial whorls often slightly clearer or even white.
Remarks
Rolán & Fernández-Garcés (2008) hesitated about the taxonomic integrity of M. ostenta, which may constitute a species with a considerable conchological variation or more than one species. They warned for the chromatic variation, the emergence of the median spiral cord of the teleoconch, and the number of whorls and spiral cords of the protoconch. Differences in the size and shape of adult shells (Fig. 7) also occur. Agreeing with the previous authors, an in-depth analysis of anatomy and DNA may solve this taxonomical problem. Meanwhile, shells from Brazil are allocated under this name.
The shell illustrated by Garcia & Lee (2011) as M. ostenta from Louisiana (southern USA) is dark and with a much rectilinear profile, not being recognized as belonging to this species. Shells from Brazil hardly ever show a slightly different coloration in the adapical spiral cord (somewhat darker or clearer) in relation to the remaining teleoconch (Fig. 7 F–S), as sometimes observed in shells from the type material.
Shells of Marshallora modesta (C.B. Adams, 1850) and Marshallora nigrocincta (C.B. Adams, 1839) are darker than those of M. ostenta, never acquiring a white coloration in the initial whorls of the teleoconch (Rolán & Fernández-Garcés 2008). In addition, M. ostenta is found in a wider bathymetric range than the two former species, which are mainly restricted to the littoral zone.
Geographical records
USA: Georgia (this study), Florida (Rolán & Fernández-Garcés 2008; Lee 2009); Cuba (type locality); Brazil: Amapá, Rio Grande do Norte, Sergipe to Rio de Janeiro (this study).
Bathymetric distribution
Depth: 3–92 m (this study).
description: Published as part of Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2020, Unraveling one of the ' Big Five': update of the taxonomy of Triphoridae (Gastropoda, Triphoroidea) from Brazil, pp. 1-170 in European Journal of Taxonomy 665 (665) on pages 20-23, DOI: 10.5852/ejt.2020.665, http://zenodo.org/record/3899047