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
Author
Angulo, Arturo
Author
López, Myrna I.
Author
Bussing, William A.
Author
Murase, Atsunobu
text
Zootaxa
2014
2014-09-18
3861
6
554
574
journal article
4098
10.11646/zootaxa.3861.6.3
38808f1d-0656-4659-bc31-0e5eee066ed6
1175-5326
5247997
8169FF7C-74C0-4385-8B67-09306D815CD2
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
.
FIGURE 2.
Rhinochimaera africana
Compagno, Stehmann & Ebert 1990
, UCR 2612–01, male, 818 mm TL, 402 mm BDL, collected in Costa Rica.
TABLE 2.
Measurements and body proportions of
Rhinochimaera africana
from Costa Rica, type and comparative material (data from
Compagno
et al.
1990
and Didier & Nakaya 1999). Measurements not attainable (i.e. structure broken) or unavailable are represented with an en–dash (–).
| Measurements |
This study, n=1 |
RUSI 27744 |
Didier & Nakaya (1999), n=22 |
| Holotype |
Min |
Max |
| TL (mm) |
820 |
1119 |
602 |
1050 |
| PCL (mm) |
643 |
901 |
480 |
845 |
| BDL (mm) |
402 |
476 |
255 |
495 |
| % BDL |
| SVL |
113.7 |
138.7 |
107.0 |
148.0 |
| TRL |
56.2 |
49.4 |
44.0 |
56.0 |
| HDL |
63.7 |
89.3 |
63.0 |
101.0 |
| SNL |
30.3 |
– |
39.0 |
68.0 |
| SWF |
5.6 |
16.0 |
8.0 |
15.0 |
| SWB |
5.5 |
13.2 |
7.0 |
11.0 |
| SHB |
4.9 |
11.3 |
7.0 |
13.0 |
| PRN |
32.3 |
60.9 |
37.0 |
73.0 |
| POR |
35.1 |
63.9 |
41.0 |
76.0 |
| POB |
43.5 |
43.5 |
46.0 |
86.0 |
| EYL |
6.4 |
5.0 |
4.0 |
6.0 |
| EYH |
5.0 |
4.2 |
3.0 |
5.0 |
| PD1 |
66.4 |
94.5 |
65.0 |
104.0 |
| PD2 |
109.5 |
130.9 |
101.0 |
138.0 |
| D1B |
21.0 |
20.2 |
16.0 |
25.0 |
| D2B |
38.6 |
46.6 |
38.0 |
52.0 |
| DSA |
39.8 |
– |
20.0 |
26.0 |
| D1H |
35.3 |
14.1 |
13.0 |
19.0 |
| D2H |
3.4 |
7.1 |
3.0 |
5.0 |
| IDS |
23.6 |
17.4 |
13.0 |
24.0 |
| DCS |
15.2 |
11.8 |
13.0 |
22.0 |
| CTL |
44.5 |
45.8 |
34.0 |
60.0 |
| CDM |
44.5 |
44.1 |
35.0 |
53.0 |
| CDH |
1.6 |
2.5 |
1.0 |
2.0 |
| CVM |
54.5 |
54.0 |
47.0 |
69.0 |
| CVH |
8.4 |
8.0 |
6.0 |
11.0 |
| CPH1 |
7.1 |
6.9 |
7.0 |
9.0 |
| CPH2 |
4.2 |
– |
– |
– |
| P1A |
39.8 |
38.2 |
27.0 |
37.0 |
| P2A |
23.6 |
20.4 |
16.0 |
24.0 |
| PPS |
45.5 |
42.2 |
34.0 |
46.0 |
| PCA |
35.8 |
34.9 |
29.0 |
40.0 |
| D1P1 |
19.4 |
– |
17.0 |
25.0 |
| D1P2 |
53.5 |
– |
46.0 |
55.0 |
| D2P1 |
47.8 |
– |
38.0 |
48.0 |
| D2P2 |
18.9 |
– |
18.0 |
25.0 |
......continued on the next page
TABLE 2.
(Continued)
| Measurements |
This study, n=1 |
RUSI 27744 |
Didier & Nakaya (1999), n=22 |
| Holotype |
Min |
Max |
| CLT |
17.9 |
– |
4.0 |
18.0 |
| FTL |
5.2 |
– |
– |
– |
| % HDL |
| TIO |
8.2 |
10.0 |
10.0 |
17.0 |
| ION |
10.3 |
24.0 |
13.0 |
25.0 |
| ONC |
13.5 |
24.0 |
17.0 |
30.0 |
| LNC |
3.0 |
5.0 |
4.0 |
7.0 |
| IOA |
5.5 |
5.0 |
5.0 |
8.0 |
| OPS |
0.8 |
1.0 |
1.0 |
2.0 |
| SLT |
4.1 |
5.0 |
5.0 |
11.0 |
| SPS |
8.7 |
8.0 |
6.0 |
11.0 |
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).