Latitriphora albida (A. Adams, 1854)

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2019, Basic anatomy of species of Triphoridae (Gastropoda, Triphoroidea) from Brazil, European Journal of Taxonomy 517, pp. 1-60 : 21-24

Latitriphora albida (A. Adams, 1854)

Figs 2E , 12–13

Material examined

BAHAMAS • [2, 1 d] specs; Abaco; 0.5 m depth; 17 Feb. 2004; C. Redfern leg.; BMSM 55442 .

Description of basic anatomy

OPERCULUM. Yellowish, ovate, moderately thick, poorly distinct whorls, nucleus subcentral, dislocated 25% from center toward margin; diameter of operculum exceeds diameter of opercular pouch in ~19%.

JAW. Wing-shaped; outer side with scales rectangular/squared, leaf-shaped, rectangular-bilobed, boneshaped or irregular; scales with micro-pores up to 400 nm in diameter; inner side with scales lanceolate, fusiform, or hexagonal in a lesser extent, surface smooth; scales of outer side 10.8–12.6 µm long, 3.9– 5.2 µm wide, ratio length/width 2.3–2.9 (rectangular scales), 10.7–11.8 µm long, 4.2–5.2 µm wide, ratio length/width 2.2–2.8 (leaf-shaped), 11.0– 11.9 µm long, 4.5–6.4 µm wide, ratio length/width 1.8–2.5 (rectangular-bilobed), 10.4–11.6 µm long, 2.4–3.2 µm wide, ratio length/width 3.5–4.9 (bone-shaped); scales of inner side 13.3–17.4 µm long, 3.4–4.4 µm wide, ratio length/width 3.3–4.0 (lanceolate), 9.5– 13.3 µm long, 1.7–2.4 µm wide, ratio length/width 4.7–6.4 (fusiform), 11.5–14.5 µm long, 4.3–4.8 µm wide, ratio length/width 2.6–3.1 (hexagonal).

RADULA. Formula 12-1-1-1-12; central tooth with three or four triangular and pointed cusps, cusp 3 absent in some rows, up to 63% of length of remaining cusps; lateral teeth comb-like, right lateral teeth with five equally-sized cusps, left lateral teeth with five or six cusps, cusp 1 absent or much smaller (28–53% of length of larger cusps) and cusp 3 with 56–70% of length of larger cusps; M1 with four cusps, cusps 1 and 4 robust, triangular and pointed, cusps 2 and 3 extremely elongated and filiform, 1.8–2.7× more elongated than remaining cusps; M2–M12 with three cusps (abnormal teeth with four cusps may occur), median one extremely elongated and filiform, 2.3–3.8× more elongated than outer cusps; central tooth 4.3–4.8 µm wide; lateral teeth 4.6–5.2 µm wide; M1 3.3–3.6 µm wide; M2–M12 1.9–2.9 µm wide.

Remarks

Live specimens of L. albida were hitherto studied only from Bahamas ( Rolán & Fernández-Garcés 1995; Redfern 2013). In addition to the description of the jaw ( Fig. 12 D–G), the present study provides important details of the radula that were unnoticed by Rolán & Fernández-Garcés (1995): (1) the central tooth was indicated to have only three cusps in Rolán & Fernández-Garcés (1995), but it is herein shown that cusp 3 (of a total of four cusps) is present in some teeth ( Fig. 13 D–E); (2) lateral teeth indeed have typically five cusps, but an additional smaller cusp can be seen in some left lateral teeth ( Fig. 13D ), possibly hidden or not yet developed in the right teeth; (3) the median filiform cusps of M1–M9 drawn by Rolán & Fernández-Garcés (1995: fig. 46) are much more reduced than those illustrated herein ( Fig. 13C, F ); (4) these authors affirmed that M1–M3 present four cusps, which is actually true for M1 but rare for M2–M3 (which often exhibit three cusps). In addition, they indicated that 13 (instead of 12) marginal teeth are present in L. albida , reflecting a possible intraspecific variation or merely a mistake therein or herein in the counting of teeth owing to considerable difficulties in such cases of overcrowded teeth.

Based on the previous description of the radula of L. albida, Rolán & Fernández-Garcés (1995) considered it to be very similar to the radula of the western Pacific and type species Nototriphora aupouria (Powell, 1937) . Actually, the tooth morphology of L. albida resembles that of Atlantic species of Nototriphora Marshall, 1983 (discussed below), with a slight difference related to the number of cusps in the central tooth (three or four in L. albida , three in Atlantic species of Nototriphora ). A molecular investigation is required to determine the degree of divergence between both genera in the Atlantic, besides evaluating the affinity between L. albida and Pacific species of Latitriphora , owing to substantial differences in the shell; e.g., the former does not constantly bear two spiral cords in the protoconch, but instead has a pattern of 2-1-2-(1) cords ( Fernandes & Pimenta 2017b), and does not exhibit a simultaneous emergence of the three spiral cords of teleoconch (Fernandes & Pimenta in prep.).

Figures

Fig. 2. Specimens studied. A. Metaxia excelsa Faber & Moolenbeek, 1991 (MZSP 122353). B. Metaxia rugulosa (C.B. Adams, 1850) (BMSM 56034). C. Cosmotriphora melanura (C.B. Adams, 1850) (MNRJ 33980). D. Iniforis pseudothomae Rolán & Fernández-Garcés, 1993 (MZSP 100957). E. Latitriphora albida (A. Adams, 1854) (BMSM 55442). F. Monophorus olivaceus (Dall, 1889) (MNRJ 34615). G. Nanaphora verbernei (Moolenbeek & Faber, 1989) (MZSP 85022). H. Nototriphora decorata (C.B. Adams, 1850) (MNRJ 28941). I. Sagenotriphora osclausum (Rolán & Fernández-Garcés, 1995) (MNRJ 35061). J. Similiphora intermedia (C.B. Adams, 1850) (MNRJ 29763). K. Strobiligera gaesona (Dall, 1927) (MZSP 53685). L. “Inella” harryleei Rolán & Fernández-Garcés, 2008 (FLMNH 450495). Scale bars: 1 mm.

Fig. 12. Latitriphora albida (A. Adams, 1854). A–G. BMSM 55442. A–B. External morphology. C. Operculum. D–G. Jaw, both sides (D–E) and outer side (F–G). Scale bars: A–B = 1 mm; C = 100 µm; D = 50 µm; E = 10 µm; F = 20 µm; G = 2 µm.

Fig. 13. Latitriphora albida (A. Adams, 1854), radula. A–F. BMSM 55442. Scale bars: A = 10 µm; B–F = 5 µm.