Ophiactis simplex (Le Conte, 1851)

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 : 118-121

Ophiactis simplex (Le Conte, 1851) Figure 4 A–F

Description.

Disk rounded (dd = 1.4 to 4.3 mm) covered by imbricating, rounded and large scales; the disk can bear small scattered spines. Primary plate conspicuous. Short spines at the edge of the disk. Radial shields small and widely separated by scales (Fig. 4D). Ventral side of the disk with spines and small imbricated scales (Fig. 4E). Oral shields oval, with a large madreporite shield evident. Adoral shields large about as wide as the oral shields, meeting within. One large oral papillae at each side of the jaw (Fig. 4F). Five arms. Dorsal arm plates wider than long with rounded edges (Fig. 4B). Ventral arm plates quadrangular with rounded edges. Lateral arm plates prominent. Four to five rounded and blunt arm spines, the lowest one shortest. A single, large and oval tentacle scale (Fig. 4C). Color of the dorsal side brown (Fig. 4A). Ventral side yellowish-cream, some ventral arm plates with darker bands (Fig. 4C, E).

Distribution.

USA (California), Mexico, Nicaragua, Costa Rica, Panama, Galapagos Islands and Peru ( Nielsen 1932, Maluf 1988, Alvarado et al. 2010, Tirado et al. 2012). In Mexico, from the Gulf of California (Baja California Sur, Sonora, Sinaloa), on the Pacific side of Baja California and Baja California Sur, Nayarit, Marías Islands, Jalisco, Michoacán, Guerrero and Oaxaca ( Solís-Marín et al. 2005, Honey-Escandón et al. 2008, Granja-Fernández and López-Pérez 2011, Ríos-Jara et al. 2013). In this study, Ophiactis simplex was collected on coral reefs from Nayarit, Jalisco, Colima, Michoacán, Guerrero and Oaxaca, from 1.5 to 22.3 m depth.

Remarks.

We collected Ophiactis simplex in the same substrata as Ophiactis savignyi (stony coral, dead coral, rocks, algae, rhodoliths and sponges). The results suggest that live stony coral is the preferred substrate for both species. Moreover, despite that both species inhabit sponges, Ophiactis savignyi was more numerous in this substrate than Ophiactis simplex . According to Lyman (1865), it is probable that larger organisms of Ophiactis simplex have five arms, while the smaller individuals have six. In this study, we only found five armed individuals of different sizes. Notwithstanding that both species of Ophiactis cohabit on the coral reefs of the Mexican Pacific, there are useful morphological characteristic to distinguish them apart: 1) small radial shields in Ophiactis simplex versus large and conspicuous radial shields in Ophiactis savignyi ; 2) numerous spines on the dorsal side and on the margin of the disk in Ophiactis savignyi whilst Ophiactis simplex can have scattered spines on the disk; 3) a single and large oral papillae on each side of the jaw in Ophiactis simplex versus two or three small oral papillae in Ophiactis savignyi ; 4) Ophiactis simplex have five arms and Ophiactis savignyi five or six; 5) smoother arms spines in Ophiactis simplex , and rugose-spinulose arm spines in Ophiactis savignyi . Ophiactis simplex is a new distribution record for the state of Colima.

Collected material.

NAYARIT: Bahía Rabijuncos (18 specimens, stony coral, 08/06/2011, ICML-UNAM 10434); Las Pozas (7 specimens, stony coral, 10/05/2011, ICML-UNAM 10420; 1 specimen, rock, 10/05/2011, ICML-UNAM 10421).

JALISCO:Cuastecomatito (2 specimens, 30/09/2010, ICML-UNAM 10338); Isla Cocinas (67 specimens, stony coral, 29/09/2010, ICML-UNAM 10328; 11 specimens, rock, 29/09/2010, ICML-UNAM 10329); Pelícanos (26 specimens, rock, 29/09/2010, ICML-UNAM 10320; 10 specimens, stony coral, 29/09/2010, ICML-UNAM 10321); La Pajarera (1 specimen, stony coral, 29/09/2010, ICML-UNAM 10308; 1 specimen, rock, 29/09/2010, ICML-UNAM 10309; 9 specimens, rhodolith, 29 /09/2010, ICML-UNAM 10310); La Palma (8 specimens, stony coral, 29/09/2010, ICML-UNAM 10325; 27 specimens, rock, 29/09/2010, ICML-UNAM 10326); La Virgencita (93 specimens, stony coral, 30/09/2010, ICML-UNAM 10341).

COLIMA:La Boquita (1 specimen, stony coral, 2.5 m, 26/02/2010, ICML-UNAM 10253; 3 specimens, stony coral, 01/10/2010, ICML-UNAM 10355); Carrizales (1 specimen, stony coral, 01/10/2010, ICML-UNAM 10350; 5 specimens, sand, 01/10/2010, ICML-UNAM 10351).

MICHOACÁN:Faro de Bucerías (10 specimens, sand, 28/09/2010, ICML-UNAM 10297), Isla Pájaros (26 specimens, stony coral, 28/09/2010, ICML-UNAM 10291; 4 specimens, rock, 28/09/2010, ICML-UNAM 10292); Morro Chino (1 specimen, stony coral, 4.3 m, 23/02/2010, ICML-UNAM 10247).

GUERRERO:Morro del Cerro Colorado (2 specimens, stony coral, 1.5 m, 30/11/2010, MHN 005-4470; 29 specimens, stony coral, 3 m, 30/11/2010, MHN 005-4456; 4 specimens, stony coral, 2.7 m, 30/11/2010, MHN 005-4429; 2 specimens, algae, 30/11/2010, ICML-UNAM 10368; 5 specimens, rhodolith, 30/11/2010, ICML-UNAM 10369; 1 specimen, sponge, 30/11/2010, ICML-UNAM 10365; 2 specimens, stony coral, 4.5 m, 23/11/2011, ICML-UNAM 10486; 12 specimens, rock, 4.5 m, 23/11/2011, ICML-UNAM 10482; 153 specimens, dead coral, 3 m, 31/05/2012, ICML-UNAM 10564; 1 specimen, rock, 5.5 m, 31/05/2012, ICML-UNAM 10565); Coral (8 specimens, rock, 5 m, 23/11/2011, ICML-UNAM 10492; 5 specimens, rhodolith, 23/11/2011, ICML-UNAM 10487); Zacatoso (22 specimens, rock, 02/03/2009, ICML-UNAM 10177; 10 specimens, stony coral, 5.1 m, 01/09/2010, ICML-UNAM 10257; 8 specimens, algae, 7.5 m, 01/12/2010, ICML-UNAM 10378; 3 specimens, stony coral, 9.1 m, 01/12/2010, UMAR-MHN 005-4419; 2 specimens, sponge, 01/12/2010, ICML-UNAM 10374; 20 specimens, algae, 16.5 m, 02/12/2010, ICML-UNAM 10383); Caleta de Chón (14 specimens, stony coral, 4.6 m, 02/12/2010, MHN 005-4453; 22 specimens, stony coral, 6.1 m, 02/12/2010, MHN 005-4424; 8 specimens, stony coral, 7.6 m, 02/12/2010, MHN 005-4467; 2 specimens, algae, 4.5 m, 02/12/2010, ICML-UNAM 10386); El Yunque (1 specimen, 5 m, 04/12/2010, ICML-UNAM 10410); Manzanillo (1 specimen, sponge, 05/03/2009, ICML-UNAM 10192; 3 specimens, rock, 05/11/2009, ICML-UNAM 10240; 1 specimen, stony coral, 3 m, 04/12/2010, MHN 005-4465; 60 specimens, rhodolith, 5.3 m, 04/12/2010, ICML-UNAM 10413; 3 specimens, rock, 6 m, 22/11/2011, ICML-UNAM 10469; 113 specimens, dead coral, 6.1 m, 30/05/2012, ICML-UNAM 10550; 8 specimens, rock, 6.1 m, 30/05/12, ICML-UNAM 10551); Morros de Potosí (6 specimens, stony coral, 11.7 m, 01/09/2010, ICML-UNAM 10262; 5 specimens, stony coral, 6.1 m, 03/12/2010, MHN 005-4444; 24 specimens, stony coral, 7.6 m, 03/12/2010, MHN 005-4479; 35 specimens, stony coral, 10.7 m, 03/12/2010, MHN 005-4475; 1 specimen, rock, 16.7 m, 03/12/2010, ICML-UNAM 10401; 5 specimens, algae, 12.2 m, 03/12/2010, ICML-UNAM 10392; 1 specimen, sponge, 03/12/2010, ICML-UNAM 10398); Palmitas (1 specimen, sponge, 6.4 m, 20/11/2011, ICML-UNAM 10455).

OAXACA:El Zapatito (1 specimen, rock, 23/04/2009, ICML-UNAM 10223); El Faro (3 specimens, rock, 22.3 m, 22/04/2009, ICML-UNAM 10214; 1 specimen, rock, 13.5 m, 24/04/2012, ICML-UNAM 10515); Mazunte (9 specimens, stony coral, 4.5 m, 03/06/2010, MHN 005-4417); Estacahuite (3 specimens, stony coral, 6.4 m, 26/03/2010, MHN 005-4400; 25 specimens, stony coral, 7.6 m, 26/03/2010, MHN 005-4408; 6 specimens, stony coral, 8.8 m, 26/03/2010, MHN 005-4404;); Salchi (2 specimens, stony coral, 6.1 m, 26/03/2010, MHN 005-4379; 4 specimens, stony coral, 7.9 m, 26/03/2010, MHN 005-4410); San Agustín (5 specimens, stony coral, 6.4 m, 23/02/2010, MHN 005-4396); La Entrega (1 specimen, dead coral, 11/09/2007, MHN 005-4325); Isla Montosa (11 specimens, stony coral, 3.6 m, 22/02/2010, MHN 005-4391; 14 specimens, stony coral, 5.8 m, 26/03/2010, MHN 005-4384; 13 specimens, stony coral, 6.1 m, 26/03/2010, MHN 005-4380); Guerrilla (1 specimen, rock, 4.9 m, 18/05/2012, ICML-UNAM 10536).