Chaunax albatrossae Ho & Ma 2022, sp. nov.
Creators: name: Ho, Hsuan-Ching
name: Ma, Wen-Chun
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Lophiiformes
Chaunacidae
Chaunax
Chaunax albatrossae

description: Chaunax albatrossae sp. nov.
English name: Albatross frogmouth
Figs. 5, 6A; Tables 1‒4
urn:lsid:zoobank.org:act: 04839D32-DD22-42B8-868A-46FB5017D48C
Holotype. MNHN 2005-0517 (77.3 mm SL), ca. 13°38’N, 121°39’E, off Luzon Island, Philippines, 195–200 m, 1 Dec. 1973.
Paratypes. Seven specimens, 59.3‒137.7 mm SL, all from Philippines: MNHN 2005-0608 (2 specimens, 59.3– 93.5 mm SL), 12°19’58.8’’N, 121°42’0’’E, Tablas Strait, between Mindoro and Tablas Island, 673–675 m, 4 Jun. 1985; MNHN 2005-0876 (3, 44.9–119.2), 12°10’4.8’’N, 121°45’0’’E, Tablas Strait, between Mindoro and Tablas Island, 700–702 m, 4 Jun. 1985; USNM 168872 (1, 113.7), 8°34’48’’N, 124°1’22.8’’E, Iligen Bay, off Mindanao Island, 8 Aug. 1909; USNM 168883 (1, 137.7), 10°0’0’’N, 125°6’36’’E, Sogod Bay, off Leyte Island, 3‒1412 m, 31 Jul. 1909.
Etymology. This species is named after the vessel USFC Albatross, treated as feminine, in service with the United States Bureau of Fisheries in the late 1800s and early 1900s, which collected the first two specimens of the present species.
Diagnosis. A small species (reaching 137.7 mm SL) of the C. abei species group with dark gray mouth cavity and dark brown to black gill chamber and gill rakers; skin covered with short, simple spinules; lateral-line neuromasts BD 2–4 (mainly 3), GH 12–13, BI 28–33 (30–32); GRii 10–12 (11); eye large (9.6‒12.0% SL); head relatively long (42.4‒46.3% SL), pre-preopercular length 31.1‒32.1% SL, predorsal length 51.1‒53.0% SL, upper-jaw 25.0‒26.2% SL; peritoneum black; body in preserved state uniformly creamy-white, including esca.
Description. Morphometric (expressed as % SL) and meristic data are given in Tables 1‒4. Data for holotype provided below followed by ranges for paratypes in parentheses, when different.
D III, 12; P 12 (11‒12, mainly 12); A 7; C 9. Lateral-line neuromasts: AB 11 (10‒11); AC 8; BD 3 (2–4); CD 6 (5–7, mainly 5‒6); DG 3; EF 6; FG 3; GH 12/13 (12‒13); BB 6; BB’ 4; BI 32/33 (28–33, mainly 30‒32), including 2/3 (2–4) on caudal fin. Gill rakers: GRi 4 +12 (10‒12)=16 (14–16); GRii 11 (10–12); GRiii 1+11 (10‒11)=12 (11 or 12); GRiv 10 (9‒10).
Head length 2.3 (2.2–2.4) in SL; head width 5.5 (5.3–5.7) in SL, 2.4 (2.3–2.4) in HL; predorsal length 1.9 (1.9– 2.0) in SL; pre-gill-opening length 1.6 (1.5–1.7) in SL; pre-preopercular length 3.2 (3.1–3.2) in SL, 1.4 (1.3–1.5) in HL; upper jaw 3.9 (3.8–4.0) in SL, 1.7 (1.7–1.8) in HL; illicial length 12.0 (11.8–12.6) in HL; pre-illicial length 13.8 (13.4–14.5) in HL; illicial trough length 6.4 (5.5–7.1) in HL; eye diameter 4.5 (4.2–4.8) in HL; post-anus length (TL1) 3.1 (2.8–3.2) in SL, 1.4 (1.3–1.4) in HL; post-dorsal length (TL2) 5.1 (4.9–5.2) in SL, 2.2 (2.1–2.3) in HL; post-anal length (TL3) 5.7 (5.3–6.5) in SL, 2.5 (2.3–2.8) in HL; caudal-peduncle height 5.2 (5.0–5.4) in HL; caudalfin length 3.4 (3.2–3.7) in SL, 1.5 (1.4–1.6) in HL.
Body slender but head globular, skull slightly elevated posteriorly. Skin thin, loose and flaccid, semi-transparent. Pectoral- and pelvic-fin rays with free tips. Caudal peduncle relatively long and slender, slightly depressed, tapering posteriorly.
Illicium short and stout, esca with large central tongue (sensu Le Danois, 1978) bearing many thin cirri. Illicial trough broadly rounded or oval, flat, relatively short and broad, subequal in length to diameter of eye pupil. Interorbital space flat and broad.
Dermal spinules relatively short and thin, all straight and simple (Fig. 6A); 4 or 5 rows of spinules in front of illicial trough; no spinules on illicial trough or illicial base; 3 or 4 pairs of spinules flanking lateral-line neuromasts.
Teeth on both jaws slender, fang-like. Band of 6–7 irregular tooth rows on upper jaw, tooth length gradually increasing from outer to inner rows; 3–4 irregular rows of teeth on lower jaw, in same arrangement as on upper jaw. Teeth on vomer small, in approximately 3 irregular rows, separated into 2 patches by medial gap. Teeth on palatine small, in elongate patch close to outer end of corresponding vomerine patch.
Cirri present on surfaces of both jaws and lateral sides of body, mainly associated with lateral-line canals; no cirri on dorsal surface of head, supraocular membranes or lower part of maxilla.
Coloration. Fresh coloration unknown but presumably uniformly pinkish, with or without colored spots or patches. Preserved specimens light brownish without marks or spots; esca creamy-white, most cirri pale or brownish distally, but some uniformly brown on anterior surface; tongue and mouth cavity blackish (some paratypes paler than others following long-term preservation); gill chamber mostly blackish, paler on ventral surface; gill arches uniformly blackish, except rakers and filaments pale; peritoneum black.
Size. Attaining 137.7 mm SL (USNM 168883); apparently a small species.
Distribution. Type series collected from central Philippines at depths of 195–702 m, excluding one specimen (USNM 168883) with imprecise depth record of 3‒1412 m. This species apparently rare in collections, possibly reflecting either low population size or restricted distribution.
Remarks. This new species is quite unusual in having a dark mouth cavity and gill chamber, something that is rare in chaunacids. Four other chaunacid species, three of them newly described below in the C. fimbriatus species group, do possess this feature but can be easily separated from C. albatrossae by the cirri on the dorsal surface of their heads and other diagnostic characters given in their respective accounts. Another species Chaunacops melanostomus, which has a uniformly dark brown body, also has dark mouth cavity and gill chamber.
All the specimens comprising the type series of C. albatrossae were initially identified by us as Chaunax apus Lloyd, 1909 (Fig. 7A), a species that also occurs in the Philippines, because both species have a uniform, creamywhite color when preserved and they share similar proportions. But the new species differs from C. apus in having a dark gray or dark brown mouth cavity and gill chamber (vs. uniformly pale); relatively short and fine, uniformly straight dermal spinules (Fig. 6A; vs. slender and curved, Fig. 6B); GH 12‒13 (vs. 12–19, mainly 14–16); and BI 28‒33 (vs. 30‒43, mainly 37‒40).
Chaunax albatrossae is likely sympatric with C. breviradius but not with C. abei. It has a relatively larger eye diameter, longer head, longer pre-opercular, predorsal and pre-gill opening lengths and longer upper-jaw length than either C. abei (Figs. 7B, C) or C. breviradius (Figs. 7D, E) from the South China Sea (Table 4), as well as the other members of the C. abei species group in the Indo-West Pacific region besides C. apus (Ho, pers. data). Moreover, C. albatrossae has short, simple dermal spinules (Fig. 6A), different from the mixture of bifurcate and simple spinules in C. abei (Fig. 6C) but similar to those of C. breviradius (Fig. 6D).
description: Published as part of Ho, Hsuan-Ching & Ma, Wen-Chun, 2022, Four new species of the frogmouth genus Chaunax (Lophiiformes: Chaunacidae) from Taiwan and the Philippines, pp. 146-179 in Zootaxa 5189 (1) on pages 150-158, DOI: 10.11646/zootaxa.5189.1.17, http://zenodo.org/record/7119369