Ophiocoma alexandri Lyman, 1860

Granja-Fernandez, Rebeca, Herrero-Perezrul, Maria D., Lopez-Perez, Ramon A., Hernandez, Luis, Rodriguez-Zaragoza, Fabian A., Jones, Robert Wallace & Pineda-Lopez, Ruben, 2014, Ophiuroidea (Echinodermata) from coral reefs in the Mexican Pacific, ZooKeys 406, pp. 101-145 : 127-129

Ophiocoma alexandri Lyman, 1860 Figure 5 G–L

Description.

Disk rounded (dd = 1.3 to 25.2 mm), covered by elongated grains. Radial shields totally covered by grains as well as the base of the arms (Fig. 5J). Ventral side of the disk covered with similar grains, but less numerous (Fig. 5K). Oral shields round. Adoral shields small and not meeting within. Four to five oral papillae on each side of the jaw, being the outer one lager. Cluster of rounded dental papillae on apex of jaw. Three of four teeth (Fig. 5L). Dorsal arm plates oval heart-shaped, wider than long (Fig. 5H). Ventral arm plates quadrangular with circular edges, wider than long (Fig. 5I). Reduced lateral arm plates. Five to seven long, stout, blunt arm spines. On first two to four joints, two lanceolated tentacle scales occur, and only one for remainder of the arm (Fig. 5K). Disk brown in color; dorsal arm plates light brown in color, some plates banded (Fig. 5G). Ventral arm plates with a brown longitudinal stripe along the arm (Fig. 5I).

Distribution.

USA, Mexico, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Colombia, Galapagos Islands ( Ziesenhenne 1937, Neira and Cantera 2005, Alvarado et al. 2010). In Mexico, from the Gulf of California (Baja California Sur, Sonora, Sinaloa), on the Pacific side of Baja California and Baja California Sur, Nayarit, Jalisco, Colima, Revillagigedo Islands, Michoacán, Guerrero and Oaxaca ( Solís-Marín et al. 2005, Honey-Escandón et al. 2008, Granja-Fernández and López-Pérez 2011). From intertidal to 70 m depth ( Maluf 1988). In this study, Ophiocoma alexandri was collected on coral reefs from Nayarit, Jalisco, Colima, Michoacán, Guerrero and Oaxaca; 2.3 to 26 m depth.

Remarks.

Ophiocoma aethiops and Ophiocoma alexandri are the largest species on the studied coral reefs. While Ophiocoma aethiops has a larger disk, Ophiocoma alexandri has larger arms. Both species can be easily identified in the field with Ophiocoma aethiops being more robust and darker color pattern, whereas Ophiocoma alexandri presents a characteristic longitudinal line along the ventral arm plates. We observed different color patterns on Ophiocoma alexandri from dark brown, light brown, yellowish and green and in all cases some dorsal arm plates were banded and the darker longitudinal stripes on the ventral plates were evident. The wide range of color patterns observed in Ophiocoma can be explained by the diurnal color change of the species that involves a replacement of brown shades by greys and black in late afternoon. The observed banded pattern may provide camouflage from predators (fish) ( Hendler 1984). Ophiocoma alexandri and Ophiocoma aethiops were collected in the same substrata (live and dead stony coral, rocks, algae and rhodoliths), and the adults of both species inhabit live and dead stony coral and rocks. Similar to Ophiocoma aethiops , Ophiocoma alexandri is a gonochoric species, without sexual dimorphism ( Benítez-Villalobos et al. 2012). Female spawning in Estacahuite reef (Oaxaca) occurs from May to December while male spawning occurs throughout the year. The spawning of Ophiocoma alexandri in Panama occurs during November and December ( Hendler 1979, Benítez-Villalobos et al. 2012).

Collected material.

NAYARIT:Las Monas (1 specimen, rock, 09/05/2011, ICML-UNAM 10419; 4 specimens, stony corals, 17/06/2010, ICML-UNAM 10358); Bahía Rabijuncos (1 specimen, stony coral, 08/06/2011, ICML-UNAM 10435).

JALISCO:Cuastecomatito (19 specimens, rock, 30/09/2010, ICML-UNAM 10337); Isla Cocinas (1 specimen, stony coral, 29/09/2010, ICML-UNAM 10330; 1 specimen, rock, 29/09/2010, ICML-UNAM 10331); La Pajarera (15 specimens, stony coral, 29/09/2010, ICML-UNAM 10312; 13 specimens, rock, 29/09/2010, ICML-UNAM 10313; 1 specimen, rhodolith, 29/09/2010, ICML-UNAM 10314); La Palma (3 specimens, rock, 29/09/2010, ICML-UNAM 10333); La Virgencita (14 specimens, stony coral, 30/09/2010, ICML-UNAM 10342); Pelícanos (17 specimens, 29/09/2010, ICML-UNAM 10303).

COLIMA:Punto B (3 specimens, 01/10/2010, ICML-UNAM 10345); Carrizales (3 specimens, 01/10/2010, ICML-UNAM 10353); L’Recif (2 specimens, 01/10/2010, ICML-UNAM 10347).

MICHOACÁN:Faro de Bucerías (1 specimen, 28/09/2010, ICML-UNAM 10299); Isla Pájaros (4 specimens, stony coral, 28/09/2010, ICML-UNAM 10294; 6 specimens, dead coral, 28/09/2010, ICML-UNAM 10286; 8 specimens, rock, 28/09/2010, ICML-UNAM 10287); Morro de Enmedio (4 specimens, stony coral, 3.7 m, 24/02/2010, ICML-UNAM 10251).

GUERRERO:Morro del Cerro Colorado (3 specimens, stony coral, 3 m 30/11/2010, MHN 005-4434; 1 specimen, rock, 30/11/2010, ICML-UNAM 10362; 8 specimens, rock, 4.5 m, 23/11/2011, ICML-UNAM 10485; 7 specimens, dead coral, 3.1 m, 31/05/2012, ICML-UNAM 10568; 6 specimens, rock, 5.5 m, 31/05/2012, ICML-UNAM 10569); Coral (9 specimens, rock, 5 m, 23/11/2011, ICML-UNAM 10494); Zacatoso (7 specimens, rock, 02/03/2009, ICML-UNAM 10179; 1 specimen, stony coral, 9.1 m, 01/12/2010, MHN 005-4445; 1 specimen, algae, 2.3 m, 01/12/2010, ICML-UNAM 10380; 1 specimen, stony coral, 5.1 m, 18/02/2010, ICML-UNAM 10243; 5 specimens, stony coral, 5.1 m, 01/09/2010, ICML-UNAM 10259; 9 specimens, rock, 9.1 m, 01/06/2012, ICML-UNAM 10579); El Chato (2 specimens, rock, 13.7 m, 04/03/2009, ICML-UNAM 10188); Caleta de Chón (8 specimens, rock, 03/03/2009, ICML-UNAM 10184; 1 specimen, algae, 4.5 m, 02/12/2010, ICML-UNAM 10387; 4 specimens, rock, 5 m, 22/11/2011, ICML-UNAM 10476); El Yunque (4 specimens, rock, 5.5 m, 04/12/2010, ICML-UNAM 10408; 3 specimens, rock, 8 m, 24/11/2011, ICML-UNAM 10503); Manzanillo (9 specimens, rock, 05/03/2009, ICML-UNAM 10194; 2 specimens, rock, 04/12/2010, ICML-UNAM 10417; 2 specimens, rhodolith, 5.3 m, 04/12/2010, ICML-UNAM 10415; 7 specimens, rock, 6 m, 22/11/2011, ICML-UNAM 10471; 52 specimens, dead coral, 6.1 m, 30/05/2012, ICML-UNAM 10553; 15 specimens, rock, 6.1 m, 30/05/2012, ICML-UNAM 10554); Morros de Potosí (5 specimens, rock, 06/03/2009, ICML-UNAM 10202; 2 specimens, stony coral, 11.7 m, 01/09/2010, ICML-UNAM 10263; 1 specimen, stony coral, 6.1 m, 03/12/2010, MHN 005-4442; 1 specimen, rock, 03/12/2010, ICML-UNAM 10402; 2 specimens, algae, 12.2 m, 03/12/2010, ICML-UNAM 10394); Palmitas (18 specimens, rock, 6.4 m, 20/11/2011, ICML-UNAM 10457); El Ripial (5 specimens, 20/11/2011, ICML-UNAM 10464).

OAXACA:Playa Coral (1 specimen, stony coral, 2.3 m, 10/09/2010, ICML-UNAM 10282); Carrizalillo (1 specimen, rock, 4.2 m, 24/04/2012, ICML-UNAM 10521); Puerto Angelito (4 specimens, rock, 10.7 m, 05/08/2007, MHN 005-4344; 10 specimens, rock, 10 m, 23/04/2012, ICML-UNAM 10510); El Zapatito (1 specimen, rock, 23/04/2009, ICML-UNAM 10225); Punto de Presión (2 specimens, rock, 26 m, 23/04/2009, ICML-UNAM 10236); El Faro (3 specimens, rock, 22.9 m, 22/04/2009, ICML-UNAM 10217; 1 specimen, hydrozoan, 21.3 m, 22/04/2009, ICML-UNAM 10218; 39 specimens, rock, 23/04/2009, ICML-UNAM 10231; 7 specimens, rock, 13.5 m, 24/04/2012, ICML-UNAM 10518); Mazunte (4 specimens, rock, 17/04/2008, MHN 005-4300; 6 specimens, rock, 20/02/2009, ICML-UNAM 10173; 2 specimens, stony coral, 4.6 m, 03/06/2010, MHN 005-4415); Estacahuite (9 specimens, rock, 21/09/2007, MHN 005-4370; 4 specimens, rock, 17/04/2008, MHN 005-4367; 4 specimens, rock, 19/02/2009, ICML-UNAM 10169; 1 specimen, stony coral, 7.6 m, 26/03/2010, MHN 005-4406; 1 specimen, stony coral, 9.7 m, 26/03/2010, MHN 005-4401; 4 specimens, stony coral, 10.3 m, 04/09/2010, ICML-UNAM 10270); La Mina (9 specimens, rock, 17/04/2008, MHN 005-4305; 8 specimens, rock, 19/02/2009, ICML-UNAM 10170); Tijera (6 specimens, rock, 16/04/2008, MHN 005-4306); Boquilla (8 specimens, rock, 21/09/2007, MHN 005-4310; 3 specimens, stony coral, 6.3 m, 08/09/2010, ICML-UNAM 10280); Salchi (13 specimens, stony coral, 6.1 m, 26/03/2010, MHN 005-4411; 6 specimens, stony coral, 7.9 m, 26/03/2010, MHN 005-4409); San Agustín (1 specimen, rock, 11/09/2007, MHN 005-4288; 2 specimens, rock, 15/09/2007, MHN 005-4361; 1 specimen, stony coral, 3.3 m, 23/02/2010, MHN 005-4397; 2 specimens, stony coral, 5.8 m, 23/02/2010, MHN 005-4393); Riscalillo (26 specimens, rock, 04/12/2008, MHN 005-4311); Jicaral (1 specimen, rock, 11/09/2007, MHN 005-4350); Dos Hermanas (8 specimens, rock, 08/08/2011, ICML-UNAM 10425); Harrys (10 specimens, rock, 9.1 m, 21/10/2011, ICML-UNAM 10437); Pomelo (12 specimens, rock, 8.8, 21/10/2011, ICML-UNAM 10447); Copal (10 specimens, rock, 9.1 m, 21 /10/2011, ICML-UNAM 10442); Isla Cacaluta (2 specimens, 11/09/2007, MHN 005-4337; 9 specimens, stony coral, 6.9 m, 06/09/2010, ICML-UNAM 10276); Órgano (5 specimens, rock, 08/08/2011, ICML-UNAM 10431); La Entrega (2 specimens, rock, 03/12/2008, MHN 005-4228; 8 specimens, stony coral, 5.3 m, 06/09/2010, ICML-UNAM 10273); Manzanilla (15 specimens, rock, 03/12/2008, MHN 005-4309; 2 specimens, dead coral, 3 m, 18/05/2012, ICML-UNAM 10525); Isla Montosa (21 specimens, stony coral, 3.6 m, 22/02/2010, MHN 005-4388; 1 specimen, stony coral, 5.8 m, 22/02/2010, MHN 005-4384) Guerrilla (10 specimens, rock, 4.9 m, 18/05/2012, ICML-UNAM 10539).