Caecum mirificum de Folin, 1867

Figures 60 A–J, 61A–H, 62A–B, 127H

Caecum mirificum de Folin, 1867a: 47, lectotype (here designated) MNHN-IM-2000-4592; 4 paralectotypes MNHN-IM-2000- 35691, Panama .

Caecum mirificum — Kisch, 1959a: 37; Keen, 1971: 397; Shasky, 1984: 27; Lightfoot, 1993b: 86; Raines & Pizzini, 2009: 116, figs. 4f, 5f.

Elephantulum mirificum — Skoglund, 1992: 29; Kaiser, 1997: 29; Finet et al. 2016: 89.

Material examined. In addition to the type material the following lots were examined. NHMLAC: LACM 1972 - 42.70, Ballena Point, Ballena Bay, Puntarenas Prov., Costa Rica, 3–16 m, 3 sh ; LACM 1970 - 16.47, Veracruz, Panama, Panama Prov., intertidal, 3 sh; LACM 1975 - 54.29, Venado Island, Panama Prov., Panama, intertidal, 30 sh ; LACM 1970 - 11.57, Ancon Point, Santa Elena, Guayas Prov., Ecuador, intertidal, 4 sh; LACM 1970 - 12.44, Ancon Point, Santa Elena, Guayas Prov., Ecuador, intertidal, 1 sh; LACM 1967 - 8.2, Piedras Blancas, Nayarit, Mexico, 16 m, 1 sh ; LACM 1938 - 131.23, Honda Bay, Veraguas Prov., Panama, 55–90 m, 4 sh ; LACM 1972 - 22.17, San Pedrito Island, Murcielagos Islands, Guanacaste Prov., Costa Rica, 10 m, 2 sh ; LACM 1972 - 46.67, Alcatraz Island, Tortugas Islands, Puntarenas Prov., Costa Rica, 2–8 m, 4 sh ; LACM 1972 - 17.48, Jobo Bay, Guanacaste Prov., Costa Rica, 1–8 m, 4 sh ; LACM 1970 - 9.34, Salinas, Guayas Prov., Ecuador, intertidal, 9 sh; LACM 1972 - 9.36, Tumbes, Tumbes Dept., Peru, intertidal, 6 sh; LACM 1965 - 21.70, Otoque Island, Panama Bay, Panama Prov., Panama, 9–27 m, 1 sh ; LACM 1965 - 25.59, Taboga Island, Panama Bay, Panama Prov., Panama, 9–27 m, 6 sh ; LACM 1933 - 136.3, Petatlan, Guerrero, Mexico, 11 m, 1 sh ; LACM 1933 - 140.5, Isabel Island, Mazatlan, Mexico, 25 m, 1 sh ; LACM 1936 - 126.9, Magdalena Bay, Baja California Sur, Mexico, 31 m, 8 sh ; LACM 1967 - 71.10, Magdalena Island, Magdalena Bay, Baja California Sur, Mexico, 8–10 m, 2 sh ; LACM 1967 - 15.19, Banderas Bay, Jalisco, Mexico, 10–20 m, 1 sh ; LACM 1973 - 7.46, Soladita Cove, SE of Guaymas, Sonora, Mexico, intertidal to 3 m, 5 sh ; LACM 1975 - 9.17, Los Angeles Bay, Baja California, Mexico, 30 m, 20 sh ; LACM 1972 - 7.37, Ista Point, Bahía Elena, Guanacaste Prov., Costa Rica, 1–12 m, 4 sh ; LACM 1938 - 179.8, Chatham Bay, Cocos Island, Costa Rica, 25 m, 1 sh ; LACM 1966 - 17.70, El Tule, Canelo Bay, Baja California, Mexico, 18–37 m, 2 sh ; LACM 1971 - 83.59, Los Arcos, Banderas Bay, Jalisco, Mexico, intertidal to 5 m, 2 sh ; LACM 1964 - 36.55, San Carlos Bay, Guaymas, Sonora, Mexico, 18–36 m, 33 sh ; LACM 1968 - 13.32, Point San Antonio, Sonora, Mexico, 18–28 m, 7 sh ; LACM 1966 - 19.67, Pulmo Bay, Baja California, Mexico Sur, 2–6 m, 2 sh ; LACM 1964 - 31.25, Puertecitos, Baja California, Mexico, 8–18 m, 48 sh ; LACM 1946 - 2.10, Millers Landing, Baja California, Mexico, intertidal, 2 sh; LACM 1967 - 65.28, Cedros Village, Cedros Island, Baja California, Mexico, 5–8 m, 1 sh ; LACM 1971 - 3.34, Abreojos Point, Baja California, Mexico, 6–10 m, 24 sh ; LACM 1941 - 352.4, NW of Natividad Island, Baja California Sur, Mexico, 55 m, 1 sh ; LACM 1972 - 117.36, NW of Natividad Island, Baja California Sur, Mexico, 20–26 m, 1 sh ; LACM 1938 - 178.4, San Jose Point, Escuintla Dept., Guatemala, 14 m, 1 sh ; LACM 1970 - 170.45, Thurloe Head, Baja California Sur, Mexico, 15–20 m, 4 sh ; LACM 1966 - 8.26, Santa Margarita Island, Baja California Sur, Mexico, intertidal, 18 sh ; LACM 1934 - 281.11, off Post Office Bay, Chatham Island, Galapagos Islands, 122 m, 1 sh ; LACM 1934 - 283.13, Hood Island, Galapagos Islands, 54 m, 2 sh ; LACM 1967 - 69.14, Huches Point, Santa Maria Bay, Baja California Sur, Mexico, 2–5 m, 6 sh ; LACM 1971 - 5.27, Pequena Point, Baja California Sur, Mexico, 3–5 m, 16 sh ; LACM 1967 - 6.9, Topolobampo Bay, Sonora, Mexico, 6–13 m, 3 sh ; LACM 1971 - 183.50, Man-O-War Cove, Magdalena Bay, Baja California Sur, Mexico, intertidal to 11 m, 28 sh ; LACM 1935 - 134.11, Secas Islands, Panama, 25 m, 2 sh ; LACM 1972 - 71.48, Dulce Gulf, Puntarenas Prov., Costa Rica, 2–16 m, 4 sh ; LACM 1935 - 138.5, Gulfo Elena, Costa Rica, 26 m, 1 sh ; LACM 1939 - 170.2, Braithwaite Bay, Socorro Island, Mexico, 18–55 m, 1 sh ; LACM 1965 - 15.42, Banderas Bay, Jalisco, Mexico, 10–21 m, 4 sh ; LACM 1933 - 178.8, Libertad, Santa Elena Bay, Guayas Prov., Ecuador, 27 m, 5 sh . SBMNH: SBMNH 214950, Roca Acero, Sonora, Mexico, 26 m, 1 sh ; SBMNH 621350, Playa Kobbe, Panama Prov., Panama, 2 sh; SBMNH 622382, Isla Salango, N side, Manabi, Ecuador, 10–25 m, 4 sh; SBMNH 621306, La Cruz de Huanacaxtle, Bahia de Banderas, Nayarit, Mexico, 7–20 m, 2 sh ; SBMNH 621358, La Cruz de Huanacaxtle, Bahia de Banderas, Nayarit, Mexico, 7–20 m, 1 sh ; SBMNH 149032, Punta Mala, Manabi, Ecuador, 10–25 m, 1 sh ; SBMNH 149034, Isla Venado, Panama Prov., Panama, intertidal, 20 sh; SBMNH 452486, La Puntilla, Salinas, Guayas, Ecuador, intertidal, 3 sh; SBMNH 128761, Salinas, Guayas, Ecuador, 2 sh; SBMNH 117046, Punta Colorado, Sonora, Mexico, intertidal, 1 sh; SBMNH 619554, Balboa, Panama Prov., Panama, 1 sh; SBMNH 128136, Isla Lobos, Mazatlan, Sinaloa, Mexico, intertidal, 80 sh; SBMNH 620544, Isla Taboga, Panama Prov., Panama, 3 sh; SBMNH 620545, Sayulita, Nayarit, Mexico, 3–6 m, 1 sh ; SBMNH 620547, La Cruz de Huanacaxtle, Nayarit, Mexico, 9–13 m, 1 sh ; SBMNH 620551, Isla Danzante, Baja California Sur, Mexico, 60–90 m, 3 sh ; SBMNH 620588, Isla Venado, Panama Prov., Panama, intertidal, 20 sh; SBMNH 132635, Caleta Lalo, Sonora, Mexico, 1 sh; SBMNH 132062, Bahia San Juanico, Baja California Sur, Mexico, 25–30 m, 1 sh ; SBMNH 621318, Puerto San Carlos, Bahia Magdalena, Baja California Sur, Mexico, 2–10 m, 3 sh ; SBMNH 621384, Bahia Herradura, Puntarenas, Costa Rica, intertidal, 1 sh ; SBMNH 621514, Playa Kobbe 1, Panama Prov., Panama, intertidal, 3 sh; SBMNH 622331, El Rubio, Tumbes, Peru, intertidal, 2 sh; SBMNH 622335, Punta Bique, Arraijan District, West Panama, Panama, intertidal, 5 sh ; SBMNH 622400, Isla San Pedro Nolasco, Sonora, Mexico, 17–23 m, 1 sh. BCD: Marua Estero, Sonora, Mexico, intertidal, 10 sh ; Cholla Bay, Sonora, Mexico, intertidal, 1 sh ; Doble Point, San Carlos Bay, Guaymas, Sonora, Mexico, 45 m, 10 sh ; off Piedras Blancas, Nayarit, Mexico, 17–19 m, 1 sh .

Original diagnosis. “Testa (quoad genus) maxima, valde elongata, cylindrica, crystallina, nitidissima, liris subacute-rotundatis, aequidistantibus, leviter expressis, longitudinaliter notata, et annulis paucis, validis, acutis, super liras transeuntibus aperturam versus cingulata; inter liras interstitiis latis, transversim minutissime striatis; apertura paululum contracta, subdeclivi, marginata; septo mamillato, granuloso, prominente, apice obtuso, dextrorso, margine laterali valde convexo subcirculari; operculo?” de Folin (1867a: 47).

Description. Protoconch and teleoconch I unknown. Teleoconch II short, sculptured with numerous curved striae (Fig. 61C), transition to teleoconch III marked by change in sculpture (Fig. 61A). Teleoconch III about two times length of teleoconch II, sculptured with low rounded longitudinal ribs covered by short, sinuous, longitudinal striae (Fig. 61D), transition to teleoconch IV marked by incised axial line (Fig. 61A). Teleoconch IV sculptured with rounded longitudinal ribs covered by sinuous longitudinal threads (Fig. 61F), transition to teleoconch V marked by suture (Fig. 62A). Teleoconch V sculptured with wide, rounded longitudinal ribs covered by weak, sinuous, longitudinal lines (Fig. 61G), transition to teleoconch VI marked by suture (Fig. 62A). Teleoconch VI (last growth stage) average size for genus [Tol 2.50–2.57 mm], tubular, rather thick, moderately and regularly arched [Larc: 0.85 –0.96 mm; Arc: 0.21–0.22 mm], subcylindrical with slight increase in diameter from posterior to aperture, semi-transparent to opaque white (Figs. 60A, 61H). Surface with longitudinal sculpture comprised of 16–20 wide, rounded, regularly spaced ribs and weak sinuous longitudinal lines (Figs. 61 G–H). Longitudinal interspaces narrower (Figs. 61 G–H). Posterior [Dpe: 0.49–0.50 mm] with thick edge, squared shoulder (Fig. 60C). Septum hemispherical, pronounced (Fig. 61H). Mucro not visible in adult stage. Aperture [Da: 0.61–0.64 mm] thick, with 3–5 rounded, distally spaced axial ribs (Fig. 61H). No varix. Lip smooth (Fig. 60C). Periostracum thick, textured, light brown (Figs. 60 G–H). Operculum thin, light brown; exterior surface with 8–10 concentric rings (Figs. 60 D–E). Conceptual reconstruction of growth stages shown in Fig. 62A.

Distribution and Habitat. From Cedros Island, Baja California, Mexico to Tumbes, Peru, including the Gulf of California, the Revillagigedo Islands, Cocos Island, and the Galapagos Islands. Intertidal to 122 m. Uncommon on sand and rubble substrates.

Remarks. The type material of Caecum mirificum is comprised of three subadults and one adult specimen. For taxonomic stability a lectotype is herein designated (MNHN-IM-2000-4592, Fig. 60F). Caecum mirificum has a thick periostracum, which at times can even appear fur-like (Figs. 60 G–H).