Caecum moorei ( Marincovich, 1973 )

Raines, Bret K., 2020, A Rosetta Stone for eastern Pacific Caecidae (Gastropoda: Caenogastropoda), Zootaxa 4827 (1), pp. 1-146 : 115-118

Caecum moorei ( Marincovich, 1973)

Figures 93 A–J, 94A–J, 95A–B, 126E

Fartulum moorei Marincovich, 1973: 30 , fig. 64, holotype LACM 1591 , Iquique , Chile.

Fartulum moorei —di Geronimo et al. 1995: 116, fig. 6; Ramírez et al. 2003: 259; Mattano & Zelaya 2013: 170.

Material examined. In addition to the type material the following lots were examined. NHMLAC: LACM 1975 - 33.10 , Algarrobo , Valparaiso Prov., Chile, 3–8 m, 3 sh ; LACM 1975 - 30.14 , Montemar , Valparaiso Prov., Chile, 3–8 m, 4 sh ; LACM 1975 - 19.18 , Antofagasta, Antofagasta Prov., Chile, intertidal to 7 m, 2 sh ; LACM 1975 - 21.13 , Antofagasta, Antofagasta Prov., Chile, 8–24 m, 8 sh ; LACM 1975 - 28.15 , Los Molles , Aconcagua Prov., Chile, intertidal, 16 sh ; LACM 1975 - 12.13 , Iquique , Tarapaca Prov., Chile, intertidal, 30 sh ; LACM 1964 - 16.26 , Iquique , Tarapaca Prov., Chile, intertidal, 148 sh ; LACM 1975 - 46.10 , Chiloe Island , Los Lagos Prov., Chile, 3–7 m, 24 sh ; LACM 1975 - 41.11 , Gulf of Corcovado , Los Lagos Prov., Chile, intertidal, 20 sh ; LACM 1975 - 43.12 , Gulf of Corcovado , Los Lagos Prov., Chile, 3–15 m, 45 sh ; LACM 1972 - 76.22 , Pucusana , Lima Dept., Peru, intertidal to 7 m, 70 sh ; LACM 1935 - 156.6 , Independencia Bay , Ica Dept., Peru, 71 m, 70 sh ; LACM 1970 - 66.13 , Iquique , Tarapaca Prov., Chile, intertidal, 40 sh ; LACM 1938 - 205.5 , Independencia Bay , Ica Dept., Peru, 16 m, 100+ sh ; LACM 1974 - 23.7 , Ancon , Lima Dept., Peru, 2 m, 2 sh ; LACM 1974 - 21.20 , Ancon , Lima Dept., Peru, 1–3 m, 9 sh ; LACM 1935 - 159.3 , Chincha Islands , Ica Dept., Peru, 63 m, 3 sh ; LACM 1938 - 211.2 , South Guanape Island , La Libertad Dept., Peru, 63 m, 10 sh .

Original diagnosis. “Teleoconch cylindrical, slightly tapered posteriorly, broadly curved for its whole length, curvature increasing slightly near aperture. Septum slightly depressed, strongly projecting, basically hemispherical but with broadly pointed dorsal mucro, angled nearly 90° to right.Apertural end circular, somewhat oblique. Surface sculpture lacking. Teleoconch light buff colored, septum white. Dimensions (in mm): total length 1.55, diameter in middle of teleoconch and at aperture 0.38, diameter at posterior end 0.32. Operculum: Circular, light to dark brown, multispiral.” Marincovich (1973: 30).

Description. Protoconch multispiral (about 1.8 whorls), planispiral, smooth ( Fig. 94A ), transition to teleoconch I marked by axial line ( Fig. 94A ). Teleoconch I short, sculptured by axial growth lines ( Fig. 94B ), transition to teleoconch II marked by slight axial incised line ( Fig. 94D ). Teleoconch II about 1.5 times length of teleoconch I, sculptured with numerous axial growth lines ( Fig. 94C ), transition to teleoconch III marked by axial incised line ( Figs. 94D, F ). Teleoconch III sculptured with numerous axial growth lines crossed by thin diffuse striae ( Fig. 94E ), transition to teleoconch IV marked by suture ( Fig. 95A ). Teleoconch IV with identical characters as previous stage ( Fig. 94H ), transition to teleoconch V marked by suture ( Fig. 95A ). Teleoconch V (last growth stage) average size for genus [Tol 2.33–2.56 mm], larger than previous stage, tubular, somewhat thin, moderately and regularly arched [Larc: 0.88–0.97 mm; Arc: 0.24–0.26 mm], subcylindrical, translucent to creamy white with brown mottling ( Figs. 93 A–B, 94J). Surface smooth with traces of longitudinal striae and axial growth lines ( Fig. 94I ). Posterior [Dpe: 0.46–0.53 mm] with thick edge, squared shoulder ( Fig. 94J ). Septum mucronate, slightly inflated ( Fig. 94J ). Mucro heel-like, positioned along dorsal margin, usually covered by septum in adult stage ( Fig. 93C ). Aperture [Da: 0.56– 0.62mm] smooth ( Fig. 94J ). No varix. Lip smooth ( Fig. 93C ). Periostracum thin, textured, brown ( Figs. 93 G–H). Operculum thin, light brown; exterior surface with 5–6 concentric rings ( Figs. 93 D–E). Conceptual reconstruction of growth stages shown in Fig. 95A .

Distribution and Habitat. From Guanape Islands, Peru to south of Puerto Montt, Chile. Intertidal to 71 m. Common on sand and rubble substrates.

Remarks. The type material of Caecum moorei is comprised of eight subadult specimens (LACM 1591, Fig. 93E ). While it does bear similarities to C. dextroversum , fresh C. moorei can be easily distinguished by the shell’s glossy surface and unique periostracum sculpture, which is finer and more sinuous ( Fig. 93F ). The distribution of C. moorei may actually overlap with C. dextroversum near northern Peru. However, no lots examined have contained both species. Mattano & Zelaya (2013) extended the range of C. moorei to 42 o S.

Figures

FIGURE 93. Caecum moorei. A. Profile view of adult stage without periostracum (LACM 1972-76.22). B. Profile view of late subadult stage without periostracum (LACM 1972-76.22). C. Ventral view of late subadult stage (LACM 1975-12.13). D. Operculum, exterior surface (LACM 1975-12.13). E. Operculum, interior surface (LACM 1975-12.13). F. Holotype, LACM 1591. G. Close-up of periostracum (LACM 1975-12.13). H. Profile view with periostracum (LACM 1975-12.13). I. Profile view without periostracum (LACM 1975-12.13). J. Close-up of surface sculpture (LACM 1975-12.13).

FIGURE 94. Caecum moorei shells at different growth stages. A. Protoconch and teleoconch I (LACM 1972-76.22). B. Surface of teleoconch I (LACM 1972-76.22). C. Surface of teleoconch II (LACM 1972-76.22). D. Teleoconchs I to III (LACM 1972-76.22). E. Surface of teleoconch III (LACM 1975-12.13). F. Teleoconchs II to III (LACM 1975-12.13). G. Teleoconch IV (LACM 1972-76.22). H. Surface of teleoconch IV (LACM 1972-76.22). I. Surface of teleoconch V (LACM 1972-76.22). J. Teleoconch V (LACM 1972-76.22).

FIGURE 95. Caecum moorei. A. Conceptual reconstruction of growth stages. B. Species distribution map.