Hydrolagus macrophthalmus de Buen 1959

Angulo, Arturo, López, Myrna I., Bussing, William A. & Murase, Atsunobu, 2014, Records of chimaeroid fishes (Holocephali: Chimaeriformes) from the Pacific coast of Costa Rica, with the description of a new species of Chimera (Chimaeridae) from the eastern Pacific Ocean, Zootaxa 3861 (6), pp. 554-574 : 568-570

Hydrolagus macrophthalmus de Buen 1959

Big eye Chimaera

( Figure 7 , Table 5 )

Material examined. 4 specimens. UCR 2611–08, n=2, females, 435–581 mm TL, 223–343 mm BDL; in front of Playa Coyote , Península de Nicoya, Guanacaste, Costa Rica (9°40'50.02" N, 85°28'4.81" W), 650–700 m, 7 April 2000, collected by M. Vitola. UCR 2901–01, n=2, females, 543–639 mm TL, 334–349 mm BDL; 44.95 Km , 253.73 ° T from Cabo Blanco, Puntarenas, Costa Rica (9º26'16.44" N, 85º29'56.04" W), 560–620 m, 24 November 2010, collected by J.M. Carvajal.

Diagnosis. Body slender; snout short and bluntly rounded; head relatively short (HDL 24.2–24.5% BDL); eyes relatively large (EYL 30.9–34.2% HDL); oral and preopercular lateral line canals sharing a short common branch from the infraorbital canal; pectoral fins relatively large (P1A 36.5–40.8% BDL), extending posterior to the insertion of pelvic fins; lateral line canal of the trunk without sinusoidal undulations; anterior and posterior regions of second dorsal fin considerably taller than middle region; anal fin absent; tail region elongate and slender (PCA 58.3–59.9% BDL); caudal-fin axis horizontal with the fin nearly symmetrical, epaxial and hypaxial lobes equal sized; uniform brown coloration across entire body, with no white markings; bluish fins. Additional morphometric measurements, expressed as percentage of body length (% BDL) or head length (% HDL), and comparative data are presented in Table 5 .

Distribution. Eastern Pacific: Central coast of Mexico ( González-Acosta et al. 2010), Costa Rica (this study), Peru and Chile, at depths of 590–1160 m ( Didier & Meckley 2009b).

Remarks. Although this species has a postulated distribution extending from the central coast of Mexico ( González-Acosta et al. 2010) to Chile ( Didier & Meckley 2009b), there are no published records between Mexico and Peru ( Didier & Meckley 2009b). The discovery of these specimens in Costa Rican waters increases the knowledge of its marine ichthyofauna and provides evidence of a broader distributional pattern for this species in the eastern Pacific region.

Figures

FIGURE 7. Hydrolagus macrophthalmus de Buen 1959, UCR 2901–01, female, 543 mm TL, 334 mm BDL, collected in Costa Rica.