Caecum draperi species novum

Figures 111 A–G, 112A–J, 113A–B, 126B

Brochina carpenteri — Lightfoot, 1993b: 82, fig. 30.

Type material. Holotype, SBMNH 637748; paratypes, SBMNH 637747 (4 figured); SBMNH 637749 (3 figured, 1 unfigured); LACM 3756 (2 figured).

Additional material examined. NHMLAC: LACM 1977-144.15, Chame Point, Panama Bay, Panama Prov., Panama, 6 sh. SBMNH: SBMNH 452501, Punta Chame, Panama Bay, Panama Prov., Panama, 6 sh; SBMNH 452539, Pier 18, Balboa, Panama Prov., Panama, 2 sh; SBMNH 452440, Pier 18, Balboa, Panama Prov., Panama, 2 sh; SBMNH 452441, Pier 18, Balboa, Panama Prov., Panama, 3 sh; SBMNH 620531, Playa Venado, Panama Prov., Panama, 20 sh; SBMNH 637751, Fuerte Amador, Panama, intertidal, 1 sh; SBMNH 637746, Punta Chame, Panama Bay, Panama Prov., Panama, 3 sh.

Type locality. Chame Point, Panama Bay, Panama Prov., Panama.

Diagnosis. Teleoconch subcylindrical, with slight increase in diameter from posterior end to aperture. Surface smooth with 12–16 large, irregularly spaced, axial ribs, which increase in strength aperturally, semi-translucent to creamy white in color. Septum mucronate, moderately inflated, with low blunt mucro. Aperture simple, rather thin. Periostracum thin, yellowish.

Description. Protoconch and teleoconch I unknown. Teleoconch II surface smooth (Fig. 112D), transition to teleoconch III marked by slight incised axial line (Fig. 112A). Teleoconch III smooth with irregularly spaced, axial ribs near apertural end (Figs. 112B), transition to teleoconch IV marked by suture (Fig. 113A). Teleoconch IV with identical characters as previous stage, transition to teleoconch V marked by suture (Fig. 113A). Teleoconch V smooth with large, irregularly spaced axial ribs (Figs. 112 G–H), transition to teleoconch VI marked by suture, followed by increase in diameter (Fig. 112I). Teleoconch VI (last growth stage) large for genus [Tol 4.90–5.18 mm], tubular, rather thin, mildly and regularly arched [Larc: 1.81–2.00 mm; Arc: 0.40–0.53 mm], subcylindrical, with slight increase in diameter from posterior to aperture, semi-translucent to creamy white (Figs. 111A, 112J). Axial sculpture of 12–16 large, rather irregularly spaced axial ribs, increasing in strength aperturally (Fig. 112J). Surface smooth with thin axial lines overall (Fig. 112G). Posterior [Dpe: 0.80–0.82 mm] with rather thick edge, squared shoulder (Fig. 111E). Septum mucronate, moderately inflated (Fig. 112J). Mucro conical, low, blunt, positioned near dorsal margin (Fig. 112C). Aperture [Da: 0.90–0.95 mm] simple, rather thin (Fig. 111E). No varix. Lip smooth (Fig. 111E). Periostracum thin, smooth, yellowish (Fig. 111A). Operculum thick, multi-layered, tapering, light brown, interior surface with central subcylindrical cusp (Fig. 111F); exterior surface with 6–7 concentric rings (Fig. 111G). Conceptual reconstruction of growth stages shown in Fig. 113A.

Etymology. The species is named in honor of the late Bertram “Bert” C. Draper (1904 – 2000), for his work on Caecidae while a Museum Associate with the Los Angeles County Museum of Natural History.

Distribution and Habitat. From Chame Point, Panama Bay, Panama to Carrillo Peninsula de Nicoya, Costa Rica. Intertidal to subtidal. Uncommon on algae and coarse sand substrates.

Remarks. Lightfoot (1993b) misidentified Caecum draperi as C. carpenteri = C. adamsi from Panama. However, C. draperi can be distinguished by its well-defined undulating axial ribs, lack of microsculpture, and unique multi-layered operculum. And as previously noted, the range of C. adamsi is restricted to southern California south to the Gulf of California, Mexico. Lightfoot also noted examining three specimens from Costa Rica. Given the close proximity to the type locality, it is reasonable to deduce these three specimens are C. draperi as well.