Ammonicera binodosa Sleurs, 1985b

Sartori, André F. & Bieler, Rüdiger, 2014, Three new species of Ammonicera from the Eastern Pacific coast of North America, with redescriptions and comments on other species of Omalogyridae (Gastropoda, Heterobranchia), Zootaxa 3872 (1), pp. 1-21 : 3

Ammonicera binodosa Sleurs, 1985b

Figure 2

Ammonicera binodosa Sleurs, 1985b, p. 25 , figs 4,6,12,16,18.

Examined material (25 specimens). LACM 84-7 , 24 specimens (4 under SEM), coral heads and sand, Pigeon Id , off Nilaveli, Sri Lanka, 8°43.5’N, 81°12.2’E, intertidal to 2m, leg. James H. McLean, Edith Abbott, Joan Sherman, 17 March 1984 ; FMNH 339458 , 1 specimen, same collection data as LACM 84-7 .

Type locality. Baros Island , North Malé Atoll, Republic of Maldives .

Diagnosis. Ammonicera with two spiral rows of nodules on the body whorl; periphery keeled.

Description. Shell planispiral, tightly coiled. Shell wall thick, opaque, glossy, dark amber in coloration. Protoconch 1 (P1) of c. 1.1 whorls (diameter 86 µ m in Figure 2B ), sculptured with 1 raised nodule at mid-whorl and reticulate sculpture peripheral to nodule, occupying a broad groove on both the apical and basal surfaces. Boundary to protoconch 2 conspicuous to poorly marked. Protoconch 2 (P2) of c. 0.65 whorls (diameter 151 µ m in Figure 2B , including P1), sculptured with c. 5 nodules at mid-whorl and reticulate sculpture peripheral to nodules on both the apical and basal surfaces; P2 nodules becoming axially elongated and reticulate sculpture fading out towards the boundary with the teleoconch. Boundary between protoconch and teleoconch conspicuous to poorly marked. Teleoconch of c. 1.6 whorls; first 1/4 whorl sculptured by axially elongated nodules extending from midwhorl to the outer suture on the apical and basal surfaces; subsequently with 2 spiral rows of nodules, 1 adjacent to the inner and 1 to the outer suture on both the apical and basal surfaces. Nodules of the outer row larger than those of the inner row and linked by a spiral cord from the second 1/2 whorl of the teleoconch onwards. Secondary spiral sculpture of the teleoconch composed of numerous very fine lirae, with interspaces approximately matching their width, overlaying the outer rows of nodules and the shell periphery. Body whorl with c. 14–17 nodules on each spiral row; periphery marked by a raised spiral cord; supraperipheral and infraperipheral walls straight to gently concave, with or without an axial sculpture of narrow and low riblets; inner lip broadly concave, flaring slightly. Aperture sub-quadrate.

Shell dimensions (in mm) and whorl counts:

Remarks. This is the first record of this species outside of its type locality in Baros Island, Maldives ( Sleurs, 1985b). We based the description above solely on the examined Sri Lankan material, which matches the original description and illustrations of this species very well. A minor but noteworthy difference is the less pronounced secondary spiral ornamentation in our specimens, which appear to lack spiral lirae altogether on the inner row of nodules (compare Figure 2 herein with fig. 4 in Sleurs, 1985b).

Figures

FIGURE 2. Ammonicera binodosa Sleurs, 1985b, LACM 84-7. A–B. Specimen 1, apical views; A. General view; B. Detail of the protoconch (interpreted boundaries P1/P2 and P2/teleoconch at white and black arrowheads, respectively); C–D. Specimen 2, umbilical views; C. General view; D. Detail of the protoconch; E. Specimen 3, dorsal view; F. Specimen 4, apertural view. Scale bars: A, C, E, F = 0.2 mm; B, D = 0.1 mm.