Ophiothrix (Ophiothrix) rudis Lyman, 1874

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 : 108-110

Ophiothrix (Ophiothrix) rudis Lyman, 1874 Figure 2 A–F

Description.

Disk rounded and bearing spinules (dd = 2.4 to 11 mm). Radial shields completely naked and separated by a line of multifid spinules (Fig. 2D).Ventral side of the disk mostly naked with scattered multifid spinules (Fig. 2E). Oral shields rounded diamond-shape, wider than long. Adoral shields narrowed and slightly separated. Oral papillae lacking. About 35 dental papillae per jaw (Fig. 2F). Dorsal arm plates wider than long, triangular or fan shaped with rounded corners; a spot distally on each arm plate (Fig. 2B). Ventral arm plates quadrangular with rounded corners. Five to seven stout, blunt, rounded, and not serrated arm spines; the two upper ones being the longest. A single, rounded, and very small tentacle scale (Fig. 2C). The color of the dorsal side of the disk is dark indigo-bluish and the ventral side is pale yellow-cream. Spines are bluish (Fig. 2A). A pale spot may be present distal to the radial shields.

Distribution.

From California, USA to Oaxaca, Mexico ( Lyman 1874, McClendon 1909, Nielsen 1932, Luke 1982). In Mexico, this species is reported from the Gulf of California, and from the coasts of the states of Baja California Sur, Nayarit, Michoacán, Guerrero and Oaxaca ( Solís-Marín et al. 2005, Honey-Escandón et al. 2008, Granja-Fernández and López-Pérez 2011). Depth 0-64 m ( Maluf 1988). In this study, Ophiothrix (Ophiothrix) rudis was collected on coral reefs from Michoacán, Guerrero and Oaxaca, between depths of 1.5 and 13.5 m.

Remarks.

Ophiothrix (Ophiothrix) rudis was found living on stony coral, dead coral, rocks, algae and on sponges. Boolotian and Leighton (1966) collected Ophiothrix (Ophiothrix) rudis from Palos Verdes, California in rocks and coarse sand. Although we made considerable effort to collect brittle stars from sand, we never found this species associated with this substrate. This species is easily distinguished from Ophiothrix (Ophiothrix) spiculata by using the following characteristics of Ophiothrix (Ophiothrix) rudis : arms not serrated, the disk only bears spinules which are larger than on Ophiothrix (Ophiothrix) spiculata , and the color pattern of the disk and on the arms. Ophiothrix (Ophiothrix) rudis is not as conspicuous or numerous as Ophiothrix (Ophiothrix) spiculata in the study area. Benítez-Villalobos (2001) observed that Ophiothrix (Ophiothrix) rudis is one of the less abundant species in La Entrega reef in Oaxaca, Mexico; we did not find the species in this coral reef area.

Collected material.

MICHOACÁN:Caleta de Campos (7 specimens, stony coral, 2.5 m, 22/02/2010, ICML-UNAM 10245).

GUERRERO:Morro del Cerro Colorado (14 specimens, stony coral, 1.5 m, 30/11/2010, MHN 005-4471; 5 specimens, stony coral, 3 m, 30/11/2010, MHN 005-4454; 1 specimen, rock, 30/11/2010, ICML-UNAM 10359; 2 specimens, rock, 4.5 m, 23/11/2011, ICML-UNAM 10477; 5 specimens, dead coral, 3 m, 31/05/2012, ICML-UNAM 10556; 3 specimens, rock, 5.5 m, 31/05/2012, ICML-UNAM 10557); Carey (1 specimen, rock, 4 m, 23/11/2011, ICML-UNAM 10495); Punta Ixtapa (4 specimens, stony coral, 4.2 m, 19/02/2010, ICML-UNAM 10255); Zacatoso (6 specimens, stony coral, 9.1 m, 01/12/2010, MHN 005-4431; 1 specimen, algae, 7.5 m, 01/12/2010, ICML-UNAM 10375; 2 specimens, sponge, 01/12/2010, ICML-UNAM 10371; 1 specimen, rock, 9.1 m, 01/06/2012, ICML-UNAM 10572; 1 specimen, sponge, 9.1 m, 01/06/2012, ICML-UNAM 10573); Caleta de Chón (6 specimens, stony coral, 4.6 m, 02/12/2010, MHN 005-4451; 2 specimens, stony coral, 6.1 m, 02/12/2010, MHN 005-4439; 2 specimens, stony coral, 7.6 m, 02/12/2010, MHN 005-4468; 1 specimen, rock, 02/12/2010, ICML-UNAM 10388; 1 specimen, algae, 4.5 m, 02/12/2010, ICML-UNAM 10385; 3 specimens, rock, 5 m, 22/11/2011, ICML-UNAM 10472); El Yunque (1 specimen, rock, 04/12/2010, ICML-UNAM 10403; 3 specimens, sponge, 5.5 m, 04/12/2010, ICML-UNAM 10404; 1 specimen, rock, 8 m, 24/11/2011, ICML-UNAM 10500); Manzanillo (1 specimen, rock, 05/11/2009, ICML-UNAM 10237; 1 specimen, stony coral, 3 m, 04/12/2010, MHN 005-4460; 1 specimen, dead coral, 6.1 m, 30/05/2012, ICML-UNAM 10542; 3 specimens, rock, 6.1 m, 30/05/2012, ICML-UNAM 10543; 2 specimens, sponge, 6.1 m, 30/05/2012, ICML-UNAM 10544); Coral (5 specimens, rock, 5 m, 23/11/2011, ICML-UNAM 10489).

OAXACA:Puerto Angelito (1 specimen, rock, 10 m, 23/04/2012, ICML-UNAM 10506); El Zapatito (3 specimens, sponge, 23/04/2009, ICML-UNAM 10220); El Faro (1 specimen, rock, 13.5 m, 24/04/2012, ICML-UNAM 10512); Salchi (1 specimens, stony coral, 6.1 m, 26/03/2010, MHN 005-4413); Riscalillo (1 specimen, rock, 04/12/2008, MHN 005-4348); Copal (8 specimens, sponge, 9.1 m, 21 /10/2011, ICML-UNAM 10440); Manzanilla (1 specimen, rock, 03/12/2008, MHN 005-4340; 2 specimens, dead coral, 3 m, 18/05/2012, ICML-UNAM 10522); Isla Montosa (2 specimens, stony coral, 5.8 m, 22/02/2010, MHN 005-4385; 5 specimens, stony coral, 6.1 m, 22/02/2010, MHN 005-4381); Guerrilla (24 specimens, rock, 4.9 m, 18/05/2012, ICML-UNAM 10534); Copalita (1 specimen, rock, 9.1 m, 18/05/2012, ICML-UNAM 10527; 2 specimens, sponge, 9.1 m, 18/05/2012, ICML-UNAM 10528).