Similiphora sp. 1, Bouchet, 1985

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2020, Unraveling one of the ‘ Big Five’: update of the taxonomy of Triphoridae (Gastropoda, Triphoroidea) from Brazil, European Journal of Taxonomy 665 (665), pp. 1-170 : 40-42

Similiphora sp. 1

Figs 18 B–L, 24H, 67

Material examined

BRAZIL – Amapá • 15 specs; 03º58′43″ N, 49º33′24″ W; 2001; MNRJ 32566 * • 4 specs; 03º58′43″ N, 49º33′24″ W; 2001; MNRJ 32567 * • 5 specs; 03º58′43″ N, 49º33′24″ W; 2001; MNRJ 32582 * • 1 spec.; 03º58′43″ N, 49º33′24″ W; 2001; MNRJ 32585 * • 1 spec.; GEOMAR II st. 124; MNRJ 33793 * • 1 spec.; AMASSEDS st. 4134; MORG 52262 • 3 specs; AMASSEDS st. 3210; MNRJ 33800 *.

BRITISH GUYANA • 1 spec.; 08º53′ N, 59º04′ W, R/V Chain Cruise 35, st. 42; depth 73–82 m; 29 Apr. 1963; MCZ 274232 .

FRENCH GUYANA • 1 spec.; 06º18′ N, 52º13′ W; depth 95–97 m; 8 Aug. 2014; OC. Ship Hermano Gines leg.; MNHN-IM-2012-43226 .

Other material (not included in the description)

BRAZIL – Pará • 1 spec.; GEOMAR II st. D; MORG 16441 *.

Description

Shell sinistral, elongated, cyrtoconoid, rectilinear to slightly convex profile, up to 3.7 mm long, 1.1 mm wide, length/width ratio 3.2 to 3.3. Protoconch multispiral, conical, 5.5–6.0 very convex whorls, 0.58– 0.70 mm long, 0.45–0.52 mm wide; embryonic shell dome-shaped, covered by small rounded granules in its abapical portion; larval shell with two faint and close spiral cords occupying the mid (adapical cord) and abapical (abapical cord) portion of each whorl, respectively situated at ~49% and ~74% of last whorl height, adapical cord emerging later at beginning of larval shell, abapical one weakening and disappearing before transition to teleoconch; ~34 rectilinear to slightly sigmoid axial ribs. Teleoconch with up to eight whorls; two spiral cords (adapical and abapical) at beginning, abapical one continuous to adapical cord of protoconch; median spiral cord emerges in third to fifth whorl, reaching same size of other cords after one to two whorls, adapical cord slightly more prominent than other cords in late whorls of some shells; on body whorl, spiral cords are 1.2–1.4 × as wide as distance between them; 16–17 nearly orthocline axial ribs; rounded nodules, with medium size; distinct, well-developed suture, with small sutural cord; wavy subperipheral cord, usually not developing nodules, two nearly smooth basal cords; no supranumerical cords; ovate aperture, 0.54–0.61 mm long, 0.44–0.51 mm wide, length/ width ratio 1.2; anterior canal moderately short to medium-sized, curved downwards, open, but almost crossed at its base by the projection of outer lip, 0.18–0.26 mm long, 0.13–0.18 mm wide, length/width ratio 1.0–2.0; posterior canal is wide sinus, 0.10–0.17 mm long, not detached from aperture. Protoconch light brown; teleoconch with whitish background, adapical spiral cord may be or not slightly darker, with faint cream-brownish coloration; base may be or not slightly darker.

Remarks

Similiphora sp. 1 is very similar to the widespread western Atlantic species S. intermedia and an endemic species from Florida ( USA), Similiphora apexdiversus (Rolán & Lee, 2008) comb. nov. ( Fig. 18A ), previously allocated to Marshallora despite the typical protoconch of Similiphora (Rolán & Fernández- Garcés 2008: fig. 8g). Similiphora sp. 1 apparently has smaller adult shells and a whitened teleoconch (sometimes with a faint cream-brownish band in the adapical spiral cord), instead of the distinct brown spiral bands in S. intermedia and the slightly darker teleoconch of S. apexdiversus comb. nov. The absence of soft parts and the great similarity with the two above-mentioned species preclude the description of Similiphora sp. 1 as a new species.

The moderately large shell of MORG 16441 ( Fig. 18L ) does not fit exactly into the definition of Similiphora sp. 1. That shell is homogeneously cream, reaching 5.2 mm to nine whorls of the teleoconch, instead of Similiphora sp. 1 (up to 3.7 mm, eight whorls).

Geographical records

British Guyana; French Guyana; Brazil: Amapá.

Bathymetric distribution

Depth: 45– 103 m.

Some considerations to species previously recorded from Brazil

Figures

Fig. 18. A. Similiphora apexdiversus (Rolán & Lee, 2008) comb. nov., holotype, FLMNH 363887. B–L. Similiphora sp. 1. B–D. MNRJ 32566*, 3.75 mm, 3.17 mm and 3.25 mm, respectively. E–K. Same shell as C. L. MORG 16441*, 5.18 mm. Scale bars: A–E, L = 1 mm; F–H = 500 µm; I, K = 100 µm; J = 50 µm.