Colpomenia ramosa

Colpomenia ramosa W. R. Taylor

Colpomenia ramosa W. R. Taylor, 1945:84, pl. 6, fig. 2; Dawson, 1949:228, 250; Dawson, 1951:52; Dawson, 1952:431; Dawson, 1961b:394; Wynne and Norris, 1976:11, fig. 8a,b; Mendoza-González and Mateo-Cid, 1985:24; Ramírez and Rojas V., 1991:16, figs. 4, 8; Martínez-Lozano et al., 1991:23; Mendoza-González et al., 1994:110; González-González et al., 1996:142; Pacheco-Ruíz and Zertuche-González, 1996b:171; Mateo-Cid and Mendoza-González, 1997:59, pl. 7: figs. 28, 29, pl. 9: fig. 39; Mateo-Cid and Mendoza-González, 2003:22; Pacheco-Ruíz et al., 2008:204; Pedroche et al., 2008:65.

Rosenvingea intricata sensu Dawson, 1944:233 [in part], pl. 52: fig. 1 [non Rosenvingea intricata (J. Agardh) Børgesen, 1914:26].

Algae forming adherent clumps, up to 4 cm broad and to 2 cm tall, with several areas of attachment. Thallus of congested, hollow, more or less cylindrical to compressed axes, irregularly subdichotomously to polychotomously branched; broader basally, becoming narrower distally; terminal branch divisions cylindrical, short, 1–2 mm in diameter by 2–3 mm long, with rounded ends. In transection, outer wall 200–500 µm thick, of 6–8 cell layers; cells larger inward toward hollow cavity, becoming smaller outward to small-celled cortex.

Plurilocular sporangia in sori, uniseriate, with 10–12 locules, 35–40 µm long.

HABITAT. Often entangled with other algae; low intertidal to shallow subtidal.

DISTRIBUTION. Gulf of California: Isla Willard, Bahía San Luis Gonzaga to Bahía Tepoca; Isla Espiritu Santo to Bahía de La Paz. Pacific coast: Baja California to Sinaloa; Guerrero to Oaxaca; Costa Rica; Galápagos Islands; Chile.

TYPE LOCALITY. Bahía Sur, Isla Cedros, Baja California, Pacific Mexico.

Colpomenia ramosa Taylor

Colpomenia ramosa Taylor, 1945:84, pl. 6: fig. 2.—Dawson, 1949:228; 1951:52; 1952:431; 1954a:117; 1961:394.

Rosenvingea intricata of Dawson, 1944:233, pl. 52; fig. 1 fin part].

DESCRIPTION.—Thalli (Figure 8) forming adherent clumps to 4 cm broad, to 2 cm tall, crisp, with several areas of attachment, irregularly subdichotomously to polychotomously branched, the branches in congested, closely set vertically directed series from broader (to 8 mm) basal portions; the terminal divisions small, cylindrical, 1–2 mm across, 2–3 mm

long, with rounded ends; becoming hollow, the wall 200–400 μm thick (to 500 μm thick in type material), 6–8 cell layers thick; small-celled cortex progressing into larger cells inward; plurilocular sporangia in sori, uniseriate, 10–12 locules, 35–40 μm long.

A collection from Academy Bay, Santa Cruz Island, Dawson 26219 (US), now extends the known distribution southward to the Galapagos Archipelago. Previously it had been reported from Isla Cedros to Costa Rica (Dawson, 1954a; Dawson, 1961).

TYPE-LOCALITY.—Bahía Sur, Isla Cedros, Pacific Baja California, Mexico.

HOLOTYPE.—W. R. Taylor 34–651 (AHFH); isotypes (MICH, US).

GULF OF CALIFORNIA DISTRIBUTION.—Occasional, Bahía San Luis Gonzaga to Bahía Tepoca, northern Gulf; Isla Espíritu Santo, southern Gulf.

GULF OF CALIFORNIA SEASONALITY.—January–March.

DISTRIBUTION.—Pacific coast of Baja California, and Gulf of California, Mexico; Pacific coast of Costa Rica; and the Galapagos Islands.

SPECIMENS EXAMINED.—Pacific Coast of Baja California. Punta Santa Rosalia, 13 Apr 1946, Dawson 1422 (AHFH), Dawson 1514 (AHFH); 9 Oct 1946, Dawson 2760 (AHFH, US); 10 Oct 1946, Dawson 2898 (AHFH). Miller’s Landing, Bahía Sebastian Vizcaino, 12 Apr 1946, Dawson 1365 (AHFH). Bahía Sur, Isla Cedros, 10 Mar 1934, W. R. Taylor 34–651 (WRT); 5 Mar 1949, Dawson 6550 (US); 19 Apr 1951, Dawson 9836 (AHFH). Punta Malarrimo, Bahía Sebastian Vizcaino, 16 Apr 1951, Dawson 10016 (AHFH). Punta San Eugenio, 1 Nov 1951, Dawson 10351 (AHFH). Bahía San Bartolome (Bahía Tortugas), 11 Feb 1954, Dawson 12267 (US). Bahía Asunción, 28 Apr 1950, Dawson 9163 (AHFH). Punta Abreojos, 30 Apr 1950, Dawson 9478 (AHFH, MICH, US). Punta Pequeña, Bahía San Juanito, 1 May 1950, Dawson 9218 (AHFH, MICH, US). Isla Santa Magdalena, 21 Aug 1946, Dawson 7876 (AHFH); 6 Apr 1955, Dawson 13406 (US). Punta Hughes, Isla Santa Magdalena, 4 May 1950, Dawson 9333 (AHFH). Isla Santa Margarita on Bahía Magdalena side, 9 Mar 1949, Dawson 6613 (US). Bahía Almejas, 7 mi NW of Cabo Tosco, Isla Santa Margarita, 24 Apr 1955, Dawson 13445 (US). Gulf of California. Sonora: Bahía Tepoca, 4 Feb 1940, Dawson 385 (AHFH); 19 Feb 1946, Dawson 825 (AHFH); 17 Feb 1973, 5 m depth, JN–6059, (US, UC). Baja California: Isla Willard, Bahía San Luis Gonzaga, 30 Jan 1940, Dawson 306 (AHFH). Puerto Calamajue, 7 m, 28 Mar 1973, JN–4688 (US), and 6 m, JN–4697, (MICH). Bahía San Gabriel, Isla Espíritu Santo, 14 Feb 1940, Dawson 606 (AHFH). Pacific Coast of Costa Rica. Port Parker, near Salinas Bay, 24, 25 Mar 1938, W. R. Taylor 39–76 (AHFH, US, WRT). Galapagos Archipelago. Academy Bay, Santa Cruz Island, 24 Jan 1964, Dawson 26219 (US).

DISTRIBUTION.—Colpomenia phaeodactyla is restricted

mostly to the middle and low intertidal range, growing on top of the platform (caliche capped coarse sandstone with shell materials) and occurring only occasionally in tide pools. Colpomenia tuberculata ranges throughout the intertidal zone from high to low tidal levels, growing on the platform, or epiphytic on other algae, particularly Laurencia paniculata. Colpomenia sinuosa is almost entirely found in the low tidal range (sometimes at higher levels, but then usually in tide pools) and extended into the shallow subtidal. While occasionally attached to rocks, it is mostly epiphytic on other algae including Sargassum.

PRODUCTIVITY.—Measurements for two species of Colpomenia growing sympatrically, reveal different rates of carbon fixation. Colpomenia phaeodactyla has a mean net rate (± one S.D.) of 2.58 ±

0.08 mg C fixed/gram dry weight/hour, and in contrast, C. tuberculata shows a mean rate of 1.10 ± 0.04 mg C fixed/gram dry weight/hour. These data were obtained by Dr. M. Littler (pers. comm.) during a high tide period using three light and two dark bottle replicates (each containing 3–5 thalli) for each species at Punta Bufeo (just north of Punta Willard, Bahía San Luis Gonzaga), Baja California del Norte, 25 Feb 1975. Light varied between 1200–1700 μE/m2/sec (PAR) and 52,500–66,000 lux during the 10:30 am to 2:50 pm period of in situ incubation.