Rhinochimaera africana Compagno, Stehmann & Ebert 1990

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 : 558-560

Rhinochimaera africana Compagno, Stehmann & Ebert 1990

Paddlenose Chimaera

( Figure 2 , Table 2 )

Material examined. 1 specimen. UCR 2612-01, male, 818 mm TL, 402 mm BDL; Isla del Caño , Puntarenas, Costa Rica (8°43'20.60" N, 84°5'50.46" W), 430–650 m, 11 April 2000 .

Diagnosis. Body elongate, with a elongate, broad and paddle-shaped pointed snout extending anterior to head (SNL 47.7% HDL), tapering to a slender tail; junction of supraorbital and infraorbital canals on ventral side of snout closer to the tip of the snout than to the nasal canal; ONC/TIO greater than 1.4 (ONC/TIO= 1.64); TIO/SWF less than 1.5 (TIO/SWF= 1.47); TIO/LNC less than 3.0 (TIO/LNC= 2.75); tooth-plates nearly smooth; eyes relatively small (EYL 6.4% BDL) and distinctly behind level of mouth; first and second dorsal fins separated by a relatively long interdorsal space (IDS 23.6% BDL) and not connected by a web of skin; caudal-fin axis weakly raised with the fin asymmetrical, epaxial caudal-fin lobe narrower than hypaxial lobe; 25 dorsal caudal tubercles; caudal filament vestigial; uniform dark brown coloration across entire body, except the oronasal region which is abruptly paler than the body. Additional morphometric measurements, expressed as percentage of body length (% BDL) or head length (% HDL), and comparative data are presented in Table 2 .

Distribution. Originally described from southern Africa from the south eastern Atlantic to south western Indian Ocean and in the Mozambique Channel at depths of 549–1450 m ( Compagno et al. 1990, Didier & Nakaya 1999), this species is now also found in the western north Pacific in Japanese waters from off Hokkaido and northern Honshu to the east China Sea, including waters of Taiwan (Didier & Nakaya 1999), and in the eastern Pacific in Costa Rican (this study) and Peruvian waters ( Didier & Meckley 2009a).

Remarks. The Costa Rican specimen share with R. africana ONC /TIO greater than 1.4, TIO/SWF less than 1.5, and TIO/LNC less than 3.0; but share with R. pacifica ONC /EYL less than 3.5 (ONC/EYL= 2.10), and SWF/ EYL less than 1.8 (SWF/EYL= 0.87). In addition, eye size (EYL 6.4% BDL) and snout width (SWF 5.6% BDL and SWB 5.5% BDL) are consistent with R. pacifica , but color, interdorsal space (IDS 23.6% BDL) and dorsal caudal tubercles count (25) are more consistent with R. africana . Didier & Meckley (2009a) report similar proportions, counts and coloration pattern for Peruvian specimens (5 in total), and mentions that these specimens may represent a new species different from both R. africana and R. pacifica . In this regard, a more carefully morphological comparative study, as well as molecular information, may be necessary to clarify this situation. In any case, the specimen herein reported represent a north range extension of at least 1500 Km on the known distribution of the genus in eastern Pacific waters, as the northernmost record was, as informed above, in Peruvian waters ( Didier & Meckley 2009a; no coordinates are provided).

Figures

FIGURE 2. Rhinochimaera africana Compagno, Stehmann & Ebert 1990, UCR 2612–01, male, 818 mm TL, 402 mm BDL, collected in Costa Rica.