Caecum insculptum Carpenter, 1857

Raines, Bret K., 2020, A Rosetta Stone for eastern Pacific Caecidae (Gastropoda: Caenogastropoda), Zootaxa 4827 (1), pp. 1-146 : 54-56

Caecum insculptum Carpenter, 1857

Figures 36 A–F, 37A–H, 38A–B, 127I

Caecum (Elephantulum) insculptum Carpenter, 1857: 315 , 2 syntypes NHMUK 1857.6 .4.1514, Mazatlan.

Caecum (Elephantulum) insculptum — Carpenter, 1858: 420.

Caecum insculptum — Carpenter, 1860: 32; Palmer, 1951: 43; Brann, 1966: pl. 32, fig. 360; Raines & Pizzini, 2009: 120, figs. 4d, 5d, 7a–c.

Caecum mirabile de Folin, 1867a: 45 , 12 syntypes MNHN-IM-2000-4593, Panama. (syn. nov.).

Elephantulum insculptum — Keen, 1968: 419, figs. 89a–b; Keen, 1971: 398, fig. 478; Shasky, 1984: 27; Skoglund, 1992: 29.

Fartulum (Elephantulum) insculptum — Draper, 1985: 4, fig. 3.

Brochina insculptum — Lightfoot, 1993b: 76, fig. 21.

Material examined. In addition to the type material the following lots were examined. NHMLAC: LACM 1965 - 28.34 , Barra de Navidad , Jalisco, Mexico, intertidal, 3 sh ; LACM 1935 - 90.10 , Secas Islands , Chiriqui Prov., Panama, 45 m, 1 sh ; LACM 1971 - 83.56 , Los Arcos, Banderas Bay , Jalisco, Mexico, intertidal to 5 m, 13 sh ; LACM 1972 - 81.22 , S of Bocapan, Tumbes Dept. , Peru, intertidal, 1 sh ; LACM 1970 - 11.56 , Ancon Point, Santa Elena , Guayas Prov., Ecuador, intertidal, 40 sh ; LACM 1970 - 12.43 , Ancon Point, Santa Elena , Guayas Prov., Ecuador, intertidal, 15 sh ; LACM 1972 - 42.68 , Ballena Point, Ballena Bay , Puntarenas Prov., Costa Rica, 3–16 m, 21 sh ; LACM 1972 - 53.34 , Herradura Bay , Puntarenas Prov., Costa Rica, 23 m, 12 sh ; LACM 1972 - 46.65 , Alcatraz Island , Tortugas Islands, Puntarenas Prov., Costa Rica, 2–8 m, 28 sh ; LACM 1972 - 30.29 , Santa Elena Point, Guanacaste Prov., Costa Rica, 13–16 m, 12 sh ; LACM 1972 - 38.33 , Penca Point, Guanacaste Prov., Costa Rica, 8–13 m, 3 sh ; LACM 1934 - 133.29 , Tangola-Tangola Bay , Oaxaca, Mexico, 5–6 m, 1 sh ; LACM 1972 - 57.44 , Quepos, Puntarenas Prov., Costa Rica, 24 m, 11 sh ; LACM 1972 - 58.63 , Quepos, Puntarenas Prov., Costa Rica, 10–24 m, 23 sh ; LACM 1968 - 41.89 , Cuastecomate Bay , Jalisco, Mexico, 5–21 m, 6 sh ; LACM 1968 - 45.53 , Cuastecomate Bay , Jalisco, Mexico, 3–6 m, 1 sh ; LACM 1966 - 15.32 , El Tule, Canelo Bay , Baja California, Mexico, intertidal, 2 sh ; LACM 1946 - 10.17 , Creston Island , Mazatlan, Sinaloa, Mexico, intertidal, 3 sh ; LACM 1935 - 136.3 , Secas Islands , Chiriqui Prov., Panama, 22 m, 1 sh ; LACM 1967 - 15.17 , Banderas Bay , Jalisco, Mexico, 10–21 m, 16 sh . SBMNH: SBMNH 452507 , Playa Tamarindo, Guanacaste, Costa Rica, 5–15 m, 4 sh ; SBMNH 127147 , Chacala, Nayarit, Mexico, 3–5 m, 1 sh ; SBMNH 452488 , La Puntilla, Salinas , Guayas, Ecuador, intertidal, 2 sh ; SBMNH 619528 , Bahia Ballena , Puntarenas, Costa Rica, 13–15 m, 6 sh ; SBMNH 128135 , Isla Lobos, Mazatlan , Sinaloa, Mexico, 6 sh ; SBMNH 620796 , Islas Ladrones, Chiriquí, Panama, 10–25 m, 1 sh ; SBMNH 620799 , Bahia Tenacatita , Cabo Tamarino, Jalisco, Mexico, 8–10 m, 1 sh ; SBMNH 620806 , Isla Pajaro [Mogo Mogo], Panama Prov. , Panama, intertidal, 3 sh ; SBMNH 621369 , Bahia Banderas , Nayarit, Mexico, 6 sh ; SBMNH 621531 , Barra de Navidad , Jalisco, Mexico, 3–45 m, 1 sh ; SBMNH 621533 , Bahia Herradura , Puntarenas, Costa Rica, intertidal, 1 sh ; SBMNH 621558 , Playa Olas Atlas, Sinaloa, Mexico, 10–25 m, 5 sh ; SBMNH 622373 , Punta Mirador, Puerto Lopez , Manabi, Ecuador, intertidal, 1 sh ; SBMNH 622381 , Punta Ancon, W side, Guayas, Ecuador, intertidal, 20 sh. BCD: Navidad Bar , Colima, Mexico, 16–32 m, 3 sh ; off Piedras Blancas, Nayarit, Mexico, 18 m, 10 sh .

Original diagnosis. “ C. ( Elephantulum ) t. juniore vitrea, diaphana, adulta solida; liris validis quadratis et interstitiis profundis ornata; aperturam versus haud tumente; septo ungulato, subprominente, apice obtuso, paululum dextrorsum verso, margine laterali subrecto; operculo?” Carpenter (1857: 315).

Description. Protoconch unknown. Teleoconch I short, sculptured with narrow longitudinal ribs and weak striae, crossed by fine axial growth lines ( Fig. 37C ), transition to teleoconch II marked by axial incised line ( Fig. 37A ). Teleoconch II about 4.5 times length of teleoconch I, sculptured with identical characters as previous stage ( Fig. 37C ), transition to teleoconch III marked by axial incised line ( Fig. 37A ). Teleoconch III sculptured with low, flattened, longitudinal ribs and weak striae, crossed by axial growth lines ( Fig. 37D ), transition to teleoconch IV marked by rapid increase in diameter ( Fig. 37B ). Teleoconch IV sculptured with rounded longitudinal ribs and weak striae ( Fig. 37F ), transition to teleoconch V marked by suture ( Fig. 38A ). Teleoconch V (last growth stage) large for genus [Tol 2.61–3.10 mm], tubular, thick, robust, mildly to moderately and regularly arched [Larc: 0.90–1.03 mm; Arc: 0.22–0.25 mm], subcylindrical, with slight increase in diameter from posterior to aperture, semi-translucent white ( Figs. 36 A–B). Longitudinal sculpture comprised of 15–20 strong, regularly spaced ribs ( Fig. 37H ). Longitudinal interspaces wider than ribs ( Figs. 37 G–H). Surface glossy, with fine, continuous, longitudinal striae in interspaces of longitudinal ridges ( Fig. 37G ). Posterior [Dpe: 0.49–0.55 mm] with thick edge, squared shoulder ( Fig. 36C ). Septum mucronate, inflated ( Fig. 36C ). Mucro heel-like, positioned on dorsal margin ( Fig. 36C ). Aperture [Da: 0.60–0.74 mm] thick, slightly flared ( Fig. 38H ). No varix. Lip smooth, with deflected peristome ( Fig. 36C ). Periostracum thin, smooth, light tan ( Fig. 36A ). Operculum thin, light brown; exterior surface with 6–7 concentric rings ( Figs. 36 D–E). Conceptual reconstruction of growth stages shown in Fig. 38A .

Distribution and Habitat. From Saladita Bay, Guaymas, Mexico to Tumbes, Peru. Intertidal to 45 m. Uncommon subtidally on sand and rubble substrates.

Remarks. The type material of Caecum insculptum is comprised of one subadult and one adult (NHMUK 1857.6.4.1514, Fig. 36F ). Raines and Pizzini (2009: 120) made reference to a “ Caecum insculptum ” complex, which represents a group of caecids with longitudinal lines and grooves. Of all the eastern Pacific species, C. insculptum has the most well-developed longitudinal grooves. Raines and Pizzini (2009: 116) also suggested C. mirabile and C. mirificum de Folin, 1867 were synonyms. However, further examination suggests that the type material of C. mirabile (MNHN-IM-2000-4593, Fig. 36G ) is actually conspecific with C. insculptum .

Figures

FIGURE 36. Caecum insculptum. A. Profile view with periostracum (LACM 1972-57.44). B. Profile view without periostracum (LACM 1972-57.44). C. Ventral view (LACM 1972-58.63). D. Operculum, exterior surface (LACM 1972-57.44). E. Operculum, interior surface (LACM 1972-57.44). F. Syntype, NHMUK 1857.6.4.1514. G. C. mirabile, syntype, MNHN-IM- 2000-4593.

FIGURE 37. Caecum insculptum shells at different growth stages. A. Teleoconchs I to III (LACM 1972-57.44). B. Teleoconchs III to IV (LACM 1972-57.44). C. surface of teleoconchs I to II (LACM 1972-57.44). D. Surface of teleoconch III (LACM 1972- 57.44). E. Teleoconch IV (LACM 1972-58.63). F. Surface of teleoconch IV (LACM 1972-58.63). G. Surface of teleoconch V (SBMNH 452507). H. Teleoconch V (SBMNH 452507).

FIGURE 38. Caecum insculptum. A. Conceptual reconstruction of growth stages. B. Species distribution map.