Caecum crebricinctum Carpenter 1864

Caecum crebricinctum Carpenter, 1864

Figures 54 A–G, 55A–I, 56A–B, 127A

Caecum (Anellum) crebricinctum Carpenter, 1864: 215, lectotype (Mclean in Mclean & Gosliner, 1996) USNM 14930, San Diego, California.

Micranellum pedroense Bartsch, 1920: 569, holotype USNM 346723, San Pedro, California.

Micranellum catalinense Bartsch, 1920: 569, holotype USNM 211331, Santa Rosa Island, California.

Micranellum profundicolum Bartsch, 1920: 569, holotype USNM 209960, San Diego, California.

Micranellum barkleyense Bartsch, 1920: 569, holotype USNM 211589, Barkley Sound, Vancouver Island, British Columbia.

Micranellum oregonense Bartsch, 1920: 569, holotype USNM 216413, Forrester Island, Alaska.

Micranellum rosanum Bartsch, 1920: 569, holotype USNM 211859a, Santa Rosa Island, California.

Micranellum crebricinctum — Palmer, 1958: 174, pl. 20, figs. 10–11a.

Caecum (Micranellum) crebricinctum —Long, 1972: 292, fig. 3.

Caecum crebricinctum — Tryon, 1886: 218, pl. 67, fig. 71; Abbott, 1974: 91, fig. 873; McLean, 1978: 30, fig. 14.3; Hertz, 1979a: 2; Draper, 1982: 29, figs. 1–3.; Draper, 1985: 3, figs. 1, 3, 7–8; McLean & Gosliner, 1996: 49; Raines, 2019: 99, figs. 2A–B.

Material examined. In addition to the type material the following lots were examined. NHMLAC: LACM 1969 - 76.30, White Pt, San Pedro, Los Angeles Co., California, intertidal, 6 sh; LACM 1980 - 59.24, Flat Rock, Palos Verdes Peninsula, Los Angeles Co., California, intertidal, 20 sh; LACM 1963 - 41.50, Coronado Islands, California, 7–13 m, 75 sh; LACM 1971 - 98.37, Coronado Islands, California, 22–24 m, 50 sh; LACM 1972 - 109.40, La Jolla, San Diego Co., California, 22–24 m, 30 sh; LACM 1969 - 67.30, Kachemak Bay, Kenai Peninsula Co., Alaska, intertidal to 20 m, 40 sh; LACM 1972 - 23.2, Kachemak Bay, Kenai Peninsula Co., Alaska, 10 m, 50 sh; LACM 1969 - 45.15, Graham Island, Queen Charlotte Islands, Canada, 54 m, 28 sh; LACM 1973 - 38.30, Louise Bay, Vancouver Island, British Columbia, Canada, 3–10 m, 3 sh; LACM 1973 - 40.21, Departure Bay, Vancouver Island, Canada, 6–23 m, 10 sh; LACM 1966 - 36.20, Sidney Channel, Vancouver Island, Canada, 20–40 m, 5 sh; LACM 1972 - 140.24, Cape Flattery, Clallam Co., Washington, 274 m, 1 sh; LACM 1966 - 56.23, Pacific Grove, Monterey Co., California, intertidal, 3 sh; LACM 1960 - 23.34, Pacific Grove, Monterey Co., California, 40 m, 45 sh; LACM 1960 - 50.19, Pacific Grove, Monterey Co., California, 65 m, 16 sh; LACM 1960 - 22.27, Monterey Bay, California, 20 m, 25 sh; LACM 1972 - 90.26, Monterey Bay, California, 15 m, 40 sh; LACM 1972 - 88.14, Pacific Grove, Monterey Co., California, 15 m, 48 sh; LACM 1972 - 130.14, Cannery Row, Monterey, Monterey Bay, Monterey Co., California, 10 m, 3 sh; LACM 1972 - 89.15, Point Lobos State Natural Reserve, Monterey Bay, Monterey Co., California, 13–23 m, 7 sh; LACM 1977 - 109.19, Diablo Canyon, San Luis Obispo County, California, 7–11 m, 30 sh; LACM 1938 - 234.4, Port San Luis, San Luis Obispo County, California, 16 m, 8 sh; LACM 1967 - 85.17, Santa Barbara, Santa Barbara Co., California, 20 m, 15 sh; LACM 1941 - 83.32, Santa Cruz Island, Santa Barbara Co., California, 70–90 m, 16 sh; LACM 1933 - 149.2, Santa Cruz Island, Santa Barbara Co., California, 20 m, 2 sh; LACM 1933 - 192.5, Santa Cruz Island, Santa Barbara Co., California, 20 m, 15 sh; LACM 1941 - 80.28, Santa Cruz Island, Santa Barbara Co., California, 100–110 m, 11 sh; LACM 1969 - 12.9, Santa Cruz Island, Santa Barbara Co., California, 13 m, 7 sh; LACM 1941 - 67.17, Santa Cruz Island, Santa Barbara Co., California, 50–55 m, 8 sh; LACM 1941 - 216.9, Santa Cruz Island, Santa Barbara Co., California, 105 m, 16 sh; LACM 1938 - 260.1, Santa Cruz Island, Santa Barbara Co., California, 100 m, 1 sh; LACM 1963 - 5.24, Santa Cruz Island, Santa Barbara Co., California, 10–16 m, 3 sh; LACM 1969 - 33.24, Anacapa Island, Los Angeles Co., California, 10 m, 15 sh; LACM 1941 - 339.4, Anacapa Island, Los Angeles Co., California, 150 m, 9 sh; LACM 1941 - 48.18, Anacapa Island, Los Angeles Co., California, 100 m, 18 sh; LACM 1969 - 28.8, Anacapa Island, Los Angeles Co., California, 95–165 m, 10 sh; LACM 1941 - 244.4, Santa Miguel Island, Santa Barbara Co., California, 70 m, 13 sh; LACM 1941 - 244.5, Santa Miguel Island, Santa Barbara Co., California, 70–80 m, 25 sh; LACM 1967 - 35.56, Santa Miguel Island, Santa Barbara Co., California, intertidal to 8 m, 2 sh; LACM 1938 - 252.1, Santa Miguel Island, Santa Barbara Co., California, 27 m, 2 sh; LACM 1941 - 337.7, Santa Miguel Island, Santa Barbara Co., California, 70 m, 7 sh; LACM 1941 - 335.11, Santa Miguel Island, Santa Barbara Co., California, 94 m, 36 sh; LACM 1938 - 230.4, Santa Rosa Island, Santa Barbara Co., California, 30 m, 12 sh; LACM 1939 - 154.6, Santa Rosa Island, Santa Barbara Co., California, 27 m, 2 sh; LACM 1971 - 243.14, Malibu Pt., Los Angeles Co., California, 10–12 m, 70 sh; LACM 1971 - 242.16, Malibu, Los Angeles Co., California, 9–12 m, 10 sh; LACM 1939 - 150.11, Santa Cruz Island, Santa Barbara Co., California, 240 m, 12 sh; LACM 1973 - 11.41, Santa Cruz Island, Santa Barbara Co., California, 11–13 m, 95 sh; LACM 1948 - 43.24, Santa Cruz Island, Santa Barbara Co., California, 11 m, 1 sh; LACM 1940 - 165.47, Santa Cruz Island, Santa Barbara Co., California, 9–16 m, 60 sh; LACM 1941 - 253.4, Santa Rosa Island, Santa Barbara Co., California, 59 m, 3 sh; LACM 1941 - 324.6, Santa Rosa Island, Santa Barbara Co., California, 145 m, 32 sh; LACM 1941 - 329.1, Santa Rosa Island, Santa Barbara Co., California, 110 m, 1 sh; LACM 1941 - 330.2, Santa Rosa Island, Santa Barbara Co., California, 245 m, 9 sh; LACM 1941 - 72.16, Santa Rosa Island, Santa Barbara Co., California, 55–58 m, 2 sh. SBMNH: SBMNH 141301, Forney’s Point, Santa Barbara County, California, USA, intertidal, 3 sh; SBMNH 214947, Point Loma, San Diego County, California, USA, 27 m, 6 sh; SBMNH 349186, Point Dume, Los Angeles County, California, USA, 5 m, 6 sh; SBMNH 349216, Forney’s Cove, Santa Barbara County, California, USA, 8 m, 1 sh; SBMNH 349189, Lions Rock, San Luis Obispo County, California, USA, 28 m, 10 sh; SBMNH 133319, Santa Rosa Island, Santa Barbara County, California, USA, 153 m, 5 sh; SBMNH 113872, Isla Cedros, off Cedros Village, Baja California [Norte], Mexico, 45 m, 4 sh; SBMNH 120521, Avalon, Los Angeles County, California, USA, 72 m, 4 sh; SBMNH 367490, La Jolla, San Diego County, California, USA, 6 sh; SBMNH 366669, Point Loma, San Diego County, California, USA, 12 sh; SBMNH 214944, Coronado, San Diego County, California, USA, 10 sh; SBMNH 101972, Coronado, San Diego County, California, USA, 27 m, 7 sh; SBMNH 2617, Redondo Beach, Los Angeles County, California, USA, 45 m, 25 sh; SBMNH 8220, Mussel Point, Monterey County, California, USA, 36 m, 3 sh; SBMNH 7400, Isla Todos Santos, Baja California [Norte], Mexico, 1 sh; SBMNH 7402, Redondo Beach, Los Angeles County, California, USA, 1 sh; SBMNH 2402, Rocky Point, Santa Barbara County, California, USA, 10 m, 3 sh; SBMNH 95, Monterey Bay, Monterey County, California, USA, 22 m, 7 sh; SBMNH 8232, San Pedro, Los Angeles County, California, USA, 6 sh; SBMNH 31997, Corona del Mar, Orange County, California, USA, intertidal, 2 sh; SBMNH 115264, Isla Coronado Sur, Baja California [Norte], Mexico, 15–18 m, 30 sh; SBMNH 103659, Del Monte, Monterey County, California, USA, 22 m, 50 sh; SBMNH 133396, Santa Barbara Island, Santa Barbara County, California, USA, 4 sh; SBMNH 100340, Avalon, Los Angeles County, California, USA, 90 m, 5 sh; SBMNH 120501, San Pedro Bay, Los Angeles County, California, USA, 22 m, 15 sh; SBMNH 619561, Point Vincente, Palos Verdes, Los Angeles County, California, USA, 18 m, 20 sh; SBMNH 110838, San Pedro, Guayas, Ecuador, 15 sh; SBMNH 113300, Point Loma, San Diego County, California, USA, 63 m, 1 sh; SBMNH 120471, Redondo Beach, Los Angeles County, California, USA, 45 m, 6 sh; SBMNH 111005, Spanish Bight, San Diego, San Diego County, California, USA, 1 sh; SBMNH 619694, Drier Bay, Valdez–Cordova County, Alaska, USA, 14 sh; SBMNH 133576, Ship Rock, Los Angeles County, California, USA, 10–25 m, 50 sh; SBMNH 120619, San Pedro, Los Angeles County, California, USA, 18 m, 100 sh; SBMNH 123194, Bahia Sebastian Vizcaino, Baja California [Norte], Mexico, 24 m, 2 sh; SBMNH 621563, Point Vincente, Palos Verdes, Los Angeles County, California, USA, 18 m, 5 sh; SBMNH 621564, Isla Todos Santos, Baja California [Norte], Mexico, 4 sh; SBMNH 622521, San Pedro, Timm’s Point, Los Angeles County, California, USA, 15 sh. BKR: off Piedras Blancas, Nayarit, Mexico, 18 m, 10 sh.

Original diagnosis. “ C. (Anellum) t., quoad genus, magna, tereti, solidiore, rufofusca, interdum radiis intensioribus longitudinalibus ornata; annulis gracillimis, creberrimis, rotundatis, haud elevatis circ. lxxx. cincta; interstitiis nullis; sculptura longitudinali nulla; apertura acuta, vix contracta, vix declivi; septo subungulato, submucronato; margine laterali recto; apice acuto, ad angulum circ. 45°, maxime elevato; operculo vix concavo, lira spirali elevata.” Carpenter (1864: 215).

Description. Protoconch paucispiral (about 1.7 whorls), planispiral, smooth (Fig. 55A), transition to teleoconch I marked by apertural varix (Fig. 55A). Teleoconch I short, sculptured with weak irregular reticular sculpture (Fig. 55B), transition to teleoconch II marked by change in sculpture (Fig. 55A). Teleoconch II about 3 times length of teleoconch I, sculptured with low axial annuli, crossed by longitudinal striae (Fig. 55C), transition to teleoconch III marked by weak axial constriction (Figs. 55A, D). Teleoconch III with similar characters as previous stage, but with somewhat stronger axial annuli (Fig. 55E), transition to teleoconch IV marked by slight axial narrowing (Fig. 55D). Teleoconch IV sculptured with flattened axial rings crossed by longitudinal striae (Fig. 55F), transition to teleoconch V marked by axial constriction (Fig. 55H). Teleoconch V (last growth stage) large for genus [Tol 4.79–6.12 mm], tubular, rather thick, stout, somewhat arched, [Larc: 1.59–2.20 mm; Arc: 0.30–0.45 mm], subcylindrical with slight increase in diameter from posterior to aperture, cream white, solid, striped, or mottled with tan to reddish brown (Figs. 54 A–C). Sculpture comprising of numerous close–set flattened axial rings and short, longitudinal striae on shoulder of axial rings and in the interspaces (Fig. 55F). Axial interspaces shallow, narrower than ribs (Figs. 55D, F). Posterior [Dpe: 0.30–0.49 mm] with rather thick edge, squared shoulder (Fig. 54D). Septum mucronate, slightly raised (Fig. 54D). Mucro with rounded point, pronounced, positioned on dorsal margin (Figs. 54 D–E). Aperture [Da: 0.45–0.75 mm] thick, slightly constricted. No varix. Lip smooth, with deflected peristome (Fig. 54D). Periostracum not observed. Operculum thin, dark brown; exterior surface with 9–11 concentric rings (Figs. 54 F–G). Conceptual reconstruction of growth stages shown in Fig. 56A.

Distribution and Habitat. From Kachemak Bay, Alaska, to Punta Abreojos, Baja California Sur, Mexico. Intertidal to 250 m. Abundant subtidally on sand and gravel substrates.

Remarks. Bartsch (1920) described the genus Micranellum for Caecum crebricinctum. However, his diagnosis of “closely spaced, slender, axial annulations” is a species level characteristic, and does not warrant a separate genus. Bartsch described six other taxa from the northeastern Pacific as well, which are listed in the synonymy above. The type material of each has been examined using SEM imaging, and all fall within the normal range of variation for C. crebricinctum. This species is the largest species known in the family, and the only member occurring in relatively deep water in the eastern Pacific. Lastly, NMNH lists USNM 14930 as a holotype. However, there were three specimens in Carpenter’s lot, one of which McLean (1996) designated as a lectotype, Fig. 54E.