Chimaera orientalis, Angulo, Lopez, Bussing & Murase, 2014

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 : 560-566

publication ID	https://doi.org/ 10.11646/zootaxa.3861.6.3
publication LSID	lsid:zoobank.org:pub:8169FF7C-74C0-4385-8B67-09306D815CD2
DOI	https://doi.org/10.5281/zenodo.5559860
persistent identifier	https://treatment.plazi.org/id/03C2878A-FFE0-FF80-44D6-FA7082B7DEC0
treatment provided by	Felipe
scientific name	Chimaera orientalis
status	sp. nov.

Treatment

Chimaera orientalis View in CoL sp. nov.

Eastern Pacific black Chimaera

( Figures 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 , Table 3 View TABLE 3 )

Holotype. UCR 2909–05.01, male, 774 mm TL, 460 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. GoogleMaps

Paratypes. 2 specimens. UCR 2909–05.02, one specimen, male, 760 mm TL, 475 mm BDL ; same data as holotype. HUMZ 174615 View Materials GoogleMaps , one specimen, female, 858 mm TL, 505 mm BDL ; off Peru (9º18'07"– 9º20'00" S, 79º47'04"– 79º47'08" W), 1103–1138 m, 23 April 2000, collected by the R / V GoogleMaps Shinkai Maru.

Diagnosis. A species of the genus Chimaera based on the presence of an anal fin. Chimaera orientalis sp. nov is distinguished from its congeners by the following combination of characters: oral and preopercular canals sharing a short common branch off the infraorbital canal; dorsal spine long (DSA 28.4–31.0% BDL), longer than first dorsal fin, when depressed reaches beyond to origin of second dorsal fin; first dorsal fin high (D1H 20.8–26.7% BDL) with a short base (D1B 10.3–12.5% BDL); interdorsal space long (IDS 8.1–10.2% BDL); pectoral fin long (P1A 40.0–43.5% BDL), when depressed reaches beyond to origin of pelvic fin base; pelvic claspers long (CLT 17.5–17.7% BDL), bifurcate, divided at about distal 40.9–43.1% of its length; dorsal caudal space long (DCS 2.0–2.5% BDL); ventral caudal margin ending slightly posterior to dorsal caudal margin; and dark brown coloration with the ventral portion of the trunk and all fins slightly darker, without distinctive markings or mottling

Description. Morphometric measurements of the holotype and paratypes, expressed as percentage of body length (% BDL) or head length (% HDL), are presented in Table 3. A View TABLE 3 medium to large bodied species with a relatively large head (HDL 24.9-26.3% BDL) which is about 20.1–20.4% of PCL. Snout relatively short, blunt, PRN 26.0–31.8% HDL and POR 37.2–43.8% HDL. Eyes relatively large (EYL 30.6–30.9% HDL) and oval in shape (EYH 58.5–63.2% EYL). Trunk stout, body depth remains similar to origin of pelvic fins where it quickly tapers posteriorly, transitioning to a caudal filament. Skin is smooth, without denticles, non-deciduous.

Oral and preopercular canals sharing a short common branch off the infraorbital canal ( Fig. 4 View FIGURE 4 ). Lateral line canal of trunk originates at a fork between occipital and otic canals with a sigmoid curve, and then with slight undulations, extends posteriorly to caudal region, where it becomes ventral and continues to caudal filament.

First dorsal fin base relatively short (D1B 10.3–12.5% BDL) and preceded by a robust dorsal fin spine. Dorsal fin spine tall (DSA 28.4–31.0% BDL), greater than head length (DSA about 1.14–1.18 times HDL) and extending past apex of first dorsal fin. Spine is slightly curved with majority occurring near distal tip, free from the first dorsal fin for at least the distal third length of spine. Two columns of serrations present on the posterior distal margin of the spine, and a slight keel present along the basal and distal anterior margins, medial anterior margin with small denticles. Dorsal fin spine, when depressed posteriorly, past second dorsal fin origin. First dorsal fin triangular, anterior margin relatively convex, posterior margin concave, height relatively large (D1H 22.8–26.7% BDL), about equal to PD1 and CVM. Interdorsal space relatively long (IDS 8.1–10.2% BDL). Second dorsal fin base relatively long (D2B 79.2–81.3% BDL), height relatively uniform throughout, but with the anterior medial-third of fin length with greatest height (D2H 3.8–4.4% BDL). Second dorsal fin height is less than 20.0% of first dorsal fin height (D2H/D1H= 0.15–0.19). Margin of second dorsal fin straight, not undulating, with posterior end of fin curving downwards to dorsal caudal fin origin.

Pectoral fins relatively large, broad and triangular (P1A 40.0–43.5% BDL), anterior margin mainly straight, convex near pointed tip. Posterior margin relatively convex, becoming rounded near inner margin. When depressed, pectoral fin reaches beyond insertion of pelvic fin. Pectoral-pelvic space relatively long (PPS 28.6–33.0% BDL) and about 79.4–93.8% of TRL. Pelvic fins relatively large and broad (P2A 50.0–51.0% P1A); anterior margin relatively straight to weakly convex becoming rounded at tip; posterior margin relatively convex. Pelvic claspers (in males) relatively long (CLT 17.5–17.7% BDL), about 40.7–43.8% P1A, bifurcate, divided at about distal 40.9–43.2% of its length, and with fleshy distal tips ( Fig. 5 View FIGURE 5 ). Female with a fleshy anal pad posterior to the cloaca, lacking in males. Pelvic-caudal space relatively short (PCA 58.3–61.1% BDL) and about 45.8–47.5% of PCL.

Frontal tenaculum (in males) with a relatively broad, short neck, and a prominent distal knob (FTL 17.6–17.9% HDL). Distal knob with 10–11 longitudinal rows of 6–12 relatively large, pointed, slender, posteriorly directed, unicuspidate spines on its sides and ventral surface.

Dorsal caudal space relatively long (DCS 2.0–2.5% BDL). Dorsal and ventral aspects of the caudal fin elongate, broad, transitioning into a whip-like tail filament. Ventral caudal lobe greater in length than the dorsal caudal margin (CDM 77.5–82.3% CVM), with the ventral caudal insertion posterior to the dorsal caudal insertion. Both caudal fin lobes are about equal in height (CDH 100.0–110.0% CVH), height less than second dorsal fin height. Anal fin present, low, with a pointed tip, separated from ventral caudal fin by a notch. Anal fin originates below second dorsal fin with anal fin tip extending beyond insertion of second dorsal fin.

Coloration. Preserved specimens dark brown with the ventral portion of the trunk and all fins slightly darker, without distinctive markings or mottling. Pelvic claspers also slightly darker with the distal portion pale.

Etymology. This species is named orientalis , from the Latin for east, given its distribution in the Pacific Ocean.

Distribution. The three type specimens were collected (2 specimens) from off Costa Rica (9º26'16.44" N, 85º29'56.04" W) and (1 specimen) from off Peru (9º18'07"– 9º20'00" S, 79º47'04"– 79º47'08" W), eastern Pacific, at depths between 560 and 1138 m. As noted by Didier & Meckley (2009b), Chimaera orientalis sp. nov. may be more widely distributed in the eastern Pacific region.

Remarks. Chimaera orientalis sp. nov. is the first species of the genus C himaera described from the eastern Pacific and can be distinguished from its other congeners by a combination of morphological and coloration differences.

Chimaera orientalis sp. nov. differs from C. argiloba Last, White & Pogonoski 2008 , from the eastern Indian ( Last et al. 2008, Didier et al. 2012), in having a shorter head length (24.9–26.3 vs. 31.3–36.1% BDL), a shorter pre-orbital length (11.8–12.6 vs. 14.7–18.7% BDL), a shorter pre-first dorsal length (26.5–29.7 vs. 29.8–36.2% BDL), a shorter pre-second dorsal length (47.2–48.7 vs. 55.5–64.2% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 17.5–21.9% BDL), a larger dorsal caudal space (2.0–2.5 vs. 0.8–1.9% BDL), a shorter total caudal length (40.1–45.5 vs. 61.5–76.8% BDL), a shorter ventral caudal margin (24.2–31.7 vs. 37.7–61.3% BDL), a shorter total clasper length (17.5–17.7 vs. 25.1–26.5% BDL), a shorter length of lateral clasper branch from fork to tip (7.2–7.6 vs. 15.2–15.5% BDL), and in the coloration pattern (the last being uniformly silvery greyish dorsally and laterally, paler ventrally), among other characters.

Chimaera orientalis sp. nov. differs from C. bahamaensis Kemper, Ebert, Didier & Compagno 2010 , from the western north Atlantic ( Kemper et al. 2010b, Didier et al. 2012), in having a shorter pre-narial length (6.7–7.9 vs. 15.4% BDL), a shorter pre-oral length (9.6–10.9 vs. 12.0% BDL), a shorter pre-orbital length (11.8–12.6 vs. 14.3% BDL), a longer eye length (7.7–8.1 vs. 6.9% BDL), a longer pre-second dorsal length (47.2–48.7 vs. 45.3% BDL), a longer dorsal spine (28.4–31.0 vs. 23.1% BDL), a higher first dorsal fin (22.8–26.7 vs. 14.4% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 13.7% BDL), a longer interdorsal space (8.1–10.2 vs. 7.5% BDL), a longer dorsal caudal space (2.0–2.5 vs. 0.2% BDL), a lower dorsal lobe of caudal fin (2.2–2.5 vs. 4.5% BDL), and a longer pectoral to pelvic space (28.6–33.0 vs. 23.4% BDL), among other characters.

Chimaera orientalis sp. nov. differs from C. cubana Howell-Rivero 1936 , from the western central Atlantic ( Didier et al. 2012), in having a shorter pre-narial length (6.7–7.9 vs. 8.4% BDL), a shorter pre-oral length (9.6–10.9 vs. 12.5% BDL), a longer dorsal spine (28.4–31.0 vs. 24.0–29.2% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 16.0–21.0% BDL), a higher dorsal lobe of caudal fin (2.2–2.5 vs. 1.4% BDL), a shorter total caudal length (40.1–45.5 vs. 72.6% BDL), a shorter ventral caudal margin fin (24.2–31.7 vs. 35.0–59.0% BDL), and in the coloration pattern (the last being uniformly silvery gray, lighter ventrally with all fins having a black distal margin), among other characters.

Chimaera orientalis sp. nov. differs from C. fulva Didier, Last & White 2008 , from the eastern Indian and southwestern Pacific ( Didier et al. 2008, 2012), in having a shorter snout-vent length (59.2–61.3 vs. 63.8–67.0% BDL), a shorter trunk length (35.1–37.0 vs. 39.4–43.5% BDL), a shorter pre-first dorsal length (26.5–29.7 vs. 29.1–31.5% BDL), a shorter pre-second dorsal length (47.2–48.7 vs. 49.5–52.7% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 14.5–18.1% BDL), a longer length of second dorsal fin base (79.2–81.3 vs. 72.9–76.7% BDL), a longer dorsal spine (28.4–31.0 vs. 22.0–27.8% BDL), a longer interdorsal space (8.1–10.2 vs. 4.5–8.5% BDL), a longer dorsal caudal space (2.0–2.5 vs. 0% BDL), bifid claspers (the last with trifid claspers), and in the coloration pattern (the last being pale brownish dorsally and laterally, with faint longitudinal stripes on sides of tail, first dorsal, caudal, pectoral and pelvic fins brown, with pale posterior margins, second dorsal fin pale brownish basally, darkish brown to dusky distally, and claspers pale), among other characters.

Chimaera orientalis sp. nov. differs from C. jordani Tanaka 1905 , from the western north Pacific and probably wester Indian ( Didier et al. 2012), in having bifid claspers (the last with trifid claspers), and in the coloration pattern (the last uniformly dark brown, with four indistinct bands in the posterior part of body), among other characters.

Chimaera orientalis sp. nov. differs from C. lignaria Didier 2002 , from the southwestern Pacific (Didier 2002, Didier et al. 2012), in having a shorter pre-first dorsal length (26.5–29.7 vs. 28.0–36.0% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 13.0–20.0% BDL), a longer length of second dorsal fin base (79.2–81.3 vs. 61.0–78.0% BDL), a longer dorsal spine (28.4–31.0 vs. 20.0–27.0% BDL), a lower ventral lobe of caudal fin (2.1–2.4 vs. 3.0–4.0% BDL), and in the coloration pattern (the last being uniformly purplish), among other characters.

Chimaera orientalis sp. nov. differs from C. macrospina Didier, Last & White 2008 , from the eastern Indian and southwestern Pacific ( Didier et al. 2008, 2012), in having a shorter length of first dorsal fin base (10.3–12.5 vs. 13.3–17.6% BDL), a higher first dorsal fin (22.8–26.7 vs. 19.4–24.4% BDL), a longer pelvic fin anterior margin (20.0–22.2 vs. 15.6–18.4% BDL), a longer interdorsal space (8.1–10.2 vs. 2.4–5.1% BDL), a longer dorsal caudal space (2.0–2.5 vs. 0–1.8% BDL), bifid claspers (the last with trifid claspers), and a longer total clasper length (17.5–17.7 vs. 10.8–13.1% BDL), among other characters.

Chimaera orientalis sp. nov. differs from C. monstrosa , from the Atlantic (including the Mediterranean sea) and Indian Oceans ( Didier et al. 2012), in having a longer dorsal spine (28.4–31.0 vs. 18.0–26.0% BDL), a higher first dorsal fin (22.8–26.7 vs. 18.0–24.0% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 14.0–21.0% BDL), a longer dorsal caudal space (2.0–2.5 vs. 0.0–1.0% BDL), and in the coloration pattern (the last with a silvery body, mottled with brown spots and undulating stripes, creamy ventrally, fins grayish, and a black margin on the distal edges of medial fins), among other characters.

Chimaera orientalis sp. nov. differs from C. notafricana Kemper, Ebert, Compagno & Didier 2010 , from the southeastern Atlantic ( Kemper et al. 2010 a, Didier et al. 2012), in having a short distance from anterior base of dorsal-fin spine to center of supratemporal canal (18.5–21.5 vs. 6.5–14.8% HDL), bifid claspers (the last with trifid claspers), a longer total clasper length (17.5–17.7 vs. 12.1–12.3% BDL), and in the coloration pattern (the last being uniform blackish brown with dark bluish streaking, and the pre-caudal tail with longitudinal light and dark stripes), among other characters.

Chimaera orientalis sp. nov. differs from C. obscura Didier, Last & White 2008 , from the southwestern Pacific ( Didier et al. 2008, 2012), in having a shorter trunk length (35.1–37.0 vs. 39.1–45.2% BDL), a longer eye length (7.7–8.1 vs. 6.1–7.3% BDL), a shorter pre-second dorsal length (47.2–48.7 vs. 49.3–49.5% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 16.8–17.9% BDL), a longer dorsal spine (28.4–31.0 vs. 27.2% BDL), a higher first dorsal fin (22.8–26.7 vs. 23.0–23.8% BDL), a lower dorsal lobe of caudal fin (2.2–2.5 vs. 3.4–3.5% BDL), and a longer dorsal caudal space (2.0–2.5 vs. 0% BDL), among other characters.

Chimaera orientalis sp. nov. differs from C. opalescens Luchetti, Iglésias & Sellos 2011 , from the eastern north Atlantic ( Luchetti et al. 2011, Didier et al. 2012), in having a shorter length of rostral canal (0.5 vs. 0.8–1.7% PCL), a shorter length of nasal canal from left to right side measured as a straight-line distance (3.1–3.4 vs. 4.4–5.5% PCL), a longer dorsal spine (22.9–24.2 vs. 12.4–19.5% PCL), bifid claspers (the last with trifid claspers), a longer total clasper length (13.7 vs. 10.3–11.4% PCL), and in the coloration pattern (the last being evenly coloured, iridescent, varying from beige to tan in adults and bronzish in juveniles, with the unpaired fins brown to purple, uniformly coloured or with pale or whitish edges), among other characters.

Chimaera orientalis sp. nov. differs from C. owstoni Tanaka 1905 , from the western north Pacific ( Didier et al. 2012), in having a shorter trunk length (35.1–37.0 vs. 38.0–46.0% BDL), a shorter pre-first dorsal fin length (26.5–29.7 vs. 29.0–35.0% BDL), a shorter pre-second dorsal fin length (47.2–48.7 vs. 49.0–57.0% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 15.0–17.0% BDL), a longer length of second dorsal fin base (79.2–81.3 vs. 75.0% BDL), a higher first dorsal fin (22.8–26.7 vs. 19.0–21.0% BDL), a longer interdorsal space (8.1–10.2 vs. 6.0–8.0% BDL), a shorter dorsal caudal margin length (18.9–24.6 vs. 24.0–30.0% BDL), a lower dorsal lobe of caudal fin (2.2–2.5 vs. 3.0% BDL), a lower ventral lobe of caudal fin (2.1–2.4 vs. 3.0–4.0% BDL), bifid claspers (the last with trifid claspers), a longer total clasper length (17.5–17.7 vs. 4.0% BDL), among other characters.

Chimaera orientalis sp. nov. differs from C. panthera , from the southwestern Pacific (Didier 1998, Didier et al. 2012), in having a shorter trunk length (35.1–37.0 vs. 40.0–41.0% BDL), a shorter pre-orbital length (11.8–12.6 vs. 14.0% BDL), a shorter pre-first dorsal fin length (26.5–29.7 vs. 30.0–32.0% BDL), a shorter pre-second dorsal fin length (47.2–48.7 vs. 52.0–56.0% BDL), a shorter length of first dorsal fin base (10.3–12.5 vs. 14.0–21.0% BDL), a longer dorsal spine (28.4–31.0 vs. 21.0% BDL), a higher first dorsal fin (22.8–26.7 vs. 22.0% BDL), a lower dorsal lobe of caudal fin (2.2–2.3 vs. 3.0–4.0% BDL), a lower ventral lobe of caudal fin (2.1–2.5 vs. 3.0–4.0% BDL), a longer total clasper length (17.5–17.7 vs. 13.0–15.0% BDL), and in the coloration pattern (the last with gray colored body and fins, covered with chocolate brown reticulations and spots, most dorsally, and the first dorsal fin with a distinct white margin), among other characters.

Finally, Chimaera orientalis sp. nov. differs from C. phantasma Jordan & Snyder 1900, from the western north Pacific ( Didier et al. 2012), in having bifid claspers (the last with trifid claspers), and in the coloration pattern (the last silvery, white below, darker above, with the dorsal and anal fin edges blackish and faint dark longitudinal stripes along the lateral line canal and trunk), among other characters.