Triphora portoricensis Rolán & Redfern, 2008

Fernandes, Maurício Romulo, 2024, Triphoridae (Gastropoda) from Martinique sampled by the MADIBENTHOS expedition, with notes on shallow-water species from Guadeloupe, Zoosystema 46 (18), pp. 457-503 : 486-488

Triphora portoricensis Rolán & Redfern, 2008

( Figs 16 ; 17 )

“ Triphora ” portoricensis Rolán & Redfern in Rolán & Fernández-Garcés 2008: 158, fig. 32A-E.

Iniforis sp. – Redfern 2001: 66, pl. 33, fig. 278A, B.

“ Triphora ” portoricensis – Redfern 2013: 127, fig. 358A, B. — Fernandes & Pimenta 2015: 505 , fig. 6. — Fernandes & Pimenta 2020: 168 .

TYPE MATERIAL. — Holotype. Puerto Rico • sh; FLMNH 363895 . Paratype. Bahamas • 1 sh; Abaco; 26°44’00”N, 77°09’00”W; 9.IX.1987; C. Redfern leg.; depth 52 m; BMSM 55395 .

TYPE LOCALITY. — Puerto Rico.

MATERIAL EXAMINED. — Martinique. MADIBENTHOS. ‘Nord Atlantique’ • 3 sh; sta. AB350; MNHN. ‘Sud Atlantique’ • 1 sh; sta. AB183; MNHN • 1 sh; sta. AB191; MNHN • 1 sh; sta. AB193; MNHN • 1 sh; sta. AS255; MNHN • 5 sh; sta. AB405; MNHN.

GEOGRAPHIC DISTRIBUTION. — Bahamas ( Rolán & Fernández-Garcés 2008; Redfern 2013); Puerto Rico ( Rolán & Fernández-Garcés 2008); Martinique (this study); Brazil. Rio Grande do Norte to Rio de Janeiro ( Fernandes & Pimenta 2015).

BATHYMETRIC DISTRIBUTION. — Recorded depth in Martinique: 14- 23 m. Previous recorded depth in the West Atlantic: 23-100 m ( Fernandes & Pimenta 2015, 2020).

EMENDED DESCRIPTION

Shell sinistral, conical to slightly pupoid, rectilinear to slightly convex profile, reaching 3.6 mm long, 1.3 mm wide, length/ width ratio 2.6-3.1; adult shells reach at least 1.9 mm in length. Protoconch sub-columnar, slightly inflated, of 2.75- 3.25 whorls, 0.40-0.58 mm long, 0.41-0.51 mm wide, weak distinction between protoconch and teleoconch; initial 0.5 whorl smooth, but axial ribs soon appear, with their adapical part emerging on the abapical part of the smooth whorl above, assuming an irregular shape, often arrow-shaped initially but varying from sigmoid, nearly orthocline, strongly opisthocline or strongly prosocline on the last whorl, where it numbers 20-34 ribs; one main spiral cord often occupying the mid portion of the whorl (sometimes the abapical portion), situated at 44-61% of last whorl height, keel-shaped, in addition to a small sutural cord. Teleoconch with up to seven whorls; two spiral cords (adapical and abapical) at the beginning, the abapical one continuous to that of protoconch; median spiral cord emerging at the end of second whorl or at the third whorl, reaching the same size than other cords after c. 1.5 whorl; at the body whorl, the three cords being equidistant and nearly the same size; 20-21 nearly orthocline axial ribs on the fifth whorl; rounded nodules of medium size, with square interspaces among nodules; distinct suture, with a sutural cord; slightly nodulose to wavy subperipheral cord, one to two smooth basal cords, often narrow, but sometimes well-developed; no distinct supranumerical cords, but a minute spiral thread sometimes appearing between abapical and subperipheral cords prior to the peristome; aperture rounded to slightly rhomboid (with a discrete notch in the posterior end), 0.47-0.83 mm long, 0.43-0.59 mm wide, length/width ratio 1.1-1.4; anterior canal very short, open, 0.07-0.15 mm long, 0.13-0.20 mm wide, length/width ratio 0.4-0.7. White to light cream shell, with adapical spiral cord and base slightly darker.

REMARKS

The shell from Guadeloupe identified by Lamy & Pointier (2018: pl. 92, fig. 11) as Triphora portoricensis is actually the holotype of Marshallora monteiroi n. comb. Some shells of T. portoricensis from Martinique ( Fig. 16 ) resemble one shell tentatively identified as M. monteiroi n. comb. ( Fig. 7K ), but the former morph has a slightly darker adapical spiral cord of teleoconch (vs spiral cords with a more homogeneous color in M. monteiroi n. comb.) and basal cords ( Fig. 17A, E ) often considerably thinner than M. monteiroi n. comb. ( Fig. 7 L-M). Shells of T. portoricensis from Martinique vary in the adult shell length ( 1.9-3.6 mm) and in the axial sculpture of the protoconch, but the largest shells are similar to the holotype from Puerto Rico ( 4.4 mm to eight teleoconch whorls vs up to seven whorls in shells from Martinique). In contrast, shells from Bahamas and Brazil are entirely white ( Redfern 2013; Fernandes & Pimenta 2015); those from Brazil have a different teleoconch sculpture in late whorls, with a more distant adapical spiral cord (not discernible in Bahamian shells, only known by juveniles), and reach up to 10 mm to 13 teleoconch whorls ( Fernandes & Pimenta 2015). This suggests that the current concept of T. portoricensis is actually a species complex masked by the similar protoconch morphology, which could be derived from convergence or parallelism.

Figures

FIG. 16. — Triphora portoricensis Rolán & Redfern, 2008: A, MNHN, sta. AB183, 2.3 mm; B, H, MNHN, sta. AB193, 1.9 mm; C, MNHN, sta. AB350, 2.3 mm; D-F, MNHN, sta. AB405, 2.4 mm, 3.2 mm, 3.3 mm; G, MNHN, sta. AS255, 3.6 mm. Scale bars: A-G, 1 mm; H, 100 μm.

FIG. 17. — Triphora portoricensis Rolán & Redfern, 2008: A, B, MNHN, sta. AB183 (Fig. 16A); C, MNHN, sta. AB193 (Fig. 16B); D, MNHN, sta. AB350 (Fig. 16C); E, H, MNHN, sta. AS255 (Fig. 16G); F, MNHN, sta. AB405 (Fig. 16E); G, MNHN, sta. AB405 (Fig. 16F). Scale bars: A, E, 200 μm; B-D, F-H, 100 μm.

FIG. 7. — Marshallora monteiroi (Rolán & Fernández-Garcés, 2015) n. comb.: A, L, MNHN, sta. AD283, 4.2 mm; B, MNHN, sta. AS482, 2.8 mm; C, MNHN, sta. AB350, 2.0 mm; D, MNHN, sta. AD275, 3.7 mm; E-H, N, MNHN, sta. AD283, 3.0 mm, 3.0 mm, 3.5 mm, 3.0 mm; I, MNHN, sta. AS252, 3.0 mm; J, MNHN, sta. GD21 (KARUBENTHOS 1), 4.6 mm; K, M, MNHN, sta. AD263, 2.7 mm. Scale bars: A-K, 1 mm; L-N, 200 μm.