Four new species of the frogmouth genus Chaunax (Lophiiformes: Chaunacidae) from Taiwan and the Philippines Author Ho, Hsuan-Ching National Museum of Marine Biology and Aquarium, Pingtung, Taiwan & Institute of Marine Biology, National Dong Hwa University, Pingtung, Taiwan & Department and Graduate Institute of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan & Australian Museum, Sydney, Australia (Research Associate) Author Ma, Wen-Chun Institute of Marine Biology, National Dong Hwa University, Pingtung, Taiwan text Zootaxa 2022 2022-09-23 5189 1 146 179 journal article 153618 10.11646/zootaxa.5189.1.17 e266879c-7e10-4ce0-8805-fad46e4129b6 1175-5326 7119369 1CC873C2-862F-444F-99BF-3CA8383508F1 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 . FIGURE 5. Chaunax albatrossae sp. nov. , holotype, MNHN 2005-0517, 77.3 mm SL, preserved. A. Dorsal view. B. Lateral view. C. Mouth cavity. 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). FIGURE 6. Dermal spinules of Chaunax species , SEM, all samples taken from skin above eye. A. C. albatrossae sp. nov. , MNHN2005-0876, 119.2 mm SL. B. C. apus , ASIZP 64564, 154 mm SL. C. C. abei , ASIZP 70159, 137 mm. D. C. breviradius , ASIZP 70154, 76 mm SL. TABLE 1. Frequency of pectoral-fin rays and lateral-line neuromasts (AB, AC, BD, CD, DG, EF, EG) of selected chaunacid species. Values are counted on both sides when available. *indicates the value of holotype.

Pectora-fin rays			AB	AC		BD
n	10	11	12	13	14	n 10 11			12	n	7	8	9	n	2	3	4
C. abei group
C. abei	40	31	9*	56	5	48*	3	56	3	53*	56 53*		3
C. albatrossae sp. nov.	16	5	11*	16	2	14*	16	16*	16	3	12*	1
C. apus	191	3	151	37	344 11 310*				23	342	3	338*	2	342 28		298*	16
C. breviradius	87	43 44*			95	3	92*	96	96*	96 92*		4
C. fimbriatus group
C. erythraeus sp. nov.	6	6*	6 5* 1			6	6*	6 4*		2
C. fimbriatus	34	2	17	5	36	2	33	1	36	36	36 14		21	2
C. obscurus sp. nov.	16	5*	11*		16	1	14*	1*	16	1	15*	16 16*
C. umbrinus	7	3	4	9	7	2	10	10	10	9	1
C. viridiretis sp. nov.	18	18	18	16*	2	18	18*	18 16*		2
C. pictus group
C. penicillatus	84	41*	36	7	92 15 66* 11*				93	1	92*	93 83*		10*
CD	DG	EF		FG
n	4	5	6	7	8	n	3 4	5	n	5	6	7	n	2	3	4
C. abei group
C. abei	56	18	35*	3*		57	57*		57	48*	9	57		57*
C. albatrossae sp. nov.	16	6	8*	2	16	16*		16	16*	16		16*
C. apus	344	1	34* 267* 41				1	342 327 15*				343	12	317*	14	348 2		343*	3
C. breviradius	95	20	93*	2	96	96*		96	96*	96		96*
C. fimbriatus group
C. erythraeus sp. nov.	6	5*	1	6	1 5*	6	6*	6	6*
C. fimbriatus	36	5	22		9	36	5 28	3	36	35	1	36		35	1
C. obscurus sp. nov.	15	10*	4*		1	16	6 9*	1	14	14*	2	16 1		15*
C. umbrinus	10	4	6	10	8 2	10	1	9	10		10
C. viridiretis sp. nov.	18	11	7	18	3* 13* 2		17	1	14*	2	18		18*
C. pictus group
C. penicillatus	94	2	48*	36		8	94	66* 24		4	94	93*	1	94		94*

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. TABLE 2. Frequency of lateral-line neuromasts (BB, BB’, GH, BI) of selected chaunacid species in present study. Values are counted on both sides when available. *indicates the value of holotype.

BB	BB’	GH
n	5 6	7	n	3	4	5	6	n	9	10	11	12	13	14	15	16	17	18
C. abei group
C. abei	30	29*	1	57	57*	53	1	4	22	30*	6*
C. albatrossae sp. nov.	8	8*	16	16*	16	9* 7*
C. apus	287	287	219 10		205*	4	241		3	16*	59	63	48	38	14
C. breviradius	48	1 47	95	7	88*	93	6*	20*	46	19	-	1	1
C. fimbriatus group
C. erythraeus sp. nov.	3	3*	6	2*	4	6	5*	1
C. fimbriatus	18	18	36	6	29	1	36	3	16	14	3
C. obscurus sp. nov.	8	6*	16	14*	1	1	16	3*	8*	5
C. umbrinus	5	1 3	1	9	1	8	10	1	5	3	1
C. viridiretis sp. nov.	9	9*	18	8*	10	18	6*	7* 5
C. pictus group
C. penicillatus	30	30*	91	26	64*	1	90	10*	32*	36	10	2
BI
n	27 28	29	30	31	32	33	34	35	36	37	38	39		40	41	42	43	44
C. abei group
C. abei	53	1	3	7	10	14 11*		4	3*
C. albatrossae sp. nov.	16	1	1	5	6	2*	1*
C. apus	179	1	1	-	1	5	10	17	34	20*	20		24	18	14	9	5
C. breviradius	93	1 1	4	21*	26*	21	10	2	5	1
C. fimbriatus group
C. erythraeus sp. nov.	6	2*	2*	-	1	1
C. fimbriatus	34	2	3	5	2	14	3	3	2
C. obscurus sp. nov.	15	1*	2	3*	2	2	1	1	1	2
C. umbrinus	8	1	2	3	2
C. viridiretis sp. nov.	18	2	4*	4	6	1	1
C. pictus group
C. penicillatus	87	1	3	6	4	10	2	18	21*	7	12		2	-	1

FIGURE 7. Three nominal species in the Chaunax abei species group. A. C. apus , ASIZP 63185, 185 mm SL, fresh. B. C. abei , ASIZP 63195, 130 mm SL, fresh. C. C. abei , NMMB-P16429, 196.2 mm SL, preserved. D. C. breviradius , NMMB-P22388, 87.6 mm SL, fresh. E. C. breviradius , NMMB-P22388, 83.8 mm SL, preserved. 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. TABLE 3. Gill raker counts of selected Chaunax species in present study, all counted on one side only.

GRi		GRii
n	11	12	13	14	15	16	17	n	8	9		10	11	12
C. abei group
C. abei	28	3	14 11*		28		24*		4
C. albatrossae sp. nov.	8	2	2	4*	8	2	5*	1
C. apus	35	1	0	2	7	17	5	3	35		1	2		11	17	4
C. breviradius	40	6	18	16	40		27	13
C. fimbriatus group
C. erythraeus sp. nov.	3	1*	2	3	1* 2
C. fimbriatus	18	4	9	5	18		14		4
C. obscurus sp. nov.	8	1	3*	4	8	2	2*		4
C. umbrinus	5	3	2	5	1	3		1
C. viridiretis sp. nov.	9	1*	3	3	2	9	5* 4
C. pictus group
C. penicillatus	38	4	11	19	4	38		12 23			3
GRiii	GRiv
C. abei group C. abei	n	8	9	10	11	12	13	n	6		7	8	9	10
C. albatrossae sp. nov.	28	16	10*	2	28		7	21*
C. apus	8	6	2*	8	7	1*
C. breviradius	35	7	21	5	2	35		1	5	27	2
C. fimbriatus group	28	2*	13	13	28		19*			8	1
C. erythraeus sp. nov.
C. fimbriatus	3	1*	1	1	3	1*		2
C. obscurus sp. nov.	16	4	9	3	18		8	10
C. umbrinus	8	4	4*	8	2	6*
C. viridiretis sp. nov.	5	3	2	5	4	1
C. pictus group	9	7	2*	9	9*
C. penicillatus
38	4	21	13	38		29			9

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. TABLE 4. Morphometric data of four species in Chuanax abei species group. HT=holotype.

C. abei	C. albatrossae sp. nov.			C. apus	C. breviradius
HT	Types, non-types		HT	Types	HT	Non-types	HT	Types , non-types
SL (mm)	81.1	92.0‒187 (n=23)		77.3	59.3‒119 (n=5)		83.0	104‒256 (n=25)		108.6	51.5‒137.6 (n=36)
In % SL	Mean (Range)	SD	Mean (Range)	SD	Mean (Range)	SD	Mean (Range)	SD
Head length	37.2	39.3 (36.9‒41.8)	1.3	42.4	43.9 (42.4‒46.3)	1.7	‒	38.5 (36.6‒40.1)	1.0	41.1	39.9 (36.1‒43.6)	1.8
Head width	16.8	17.4 (16.0‒20.1)	1.1	17.7	18.6 (17.6‒20.4)	1.1	‒	15.5 (13.3‒17.3)	1.1	16.7	17.1 (15.2‒19.4)	1.0
Pre-preopercular length	26.5	27.1 (25.1‒28.8)	0.9	31.3	31.6 (31.1‒32.1)	0.4	30.1	26.2 (24.2‒28.8)	1.4	26.5	27.5 (25.7‒30.2)	1.1
Pre-dorsal length	48.5	49.7 (45.0‒53.4)	2.4	51.1	52.1 (51.1‒53.0)	0.8	‒	45.1 (43.3‒48.3)	1.2	47.2	48.7 (44.6‒53.5)	2.4
Pre-gill opening length	61.3	62.9 (60.4‒64.6)	1.2	66.9	63.2 (59.5‒66.9)	3.0	57.3	58.5 (56.5‒60.0)	1.0	62.7	63.7 (59.1‒67.8)	2.2
Illicial length	3.9	4.1 (3.3‒4.9)	0.4	3.4	3.6 (3.2‒3.9)	0.3	‒	3.4 (2.7‒4.1)	0.4	‒	5.3 (4.0‒6.3)	0.6
Illcial trough length	6.9	7.8 (6.8‒9.3)	0.6	6.0	7.1 (6.0‒7.9)	0.8	‒	5.2 (4.3‒7.1)	0.8	6.4	8.3 (6.4‒9.9)	0.7
Pre-illicial trough	2.6	3.8 (3.1‒4.6)	0.4	3.6	3.1 (2.4‒3.6)	0.4	‒	2.9 (1.4‒4.1)	0.8	3.7	4.4 (3.2‒5.5)	0.6
Eye diameter	7.8	8.3 (7.5‒9.6)	0.6	10.2	10.3 (9.6‒12.0)	1.0	8.8	8.0 (6.9‒9.7)	0.8	7.7	8.0 (6.4‒10.2)	0.9
Upper jaw length	19.4	20.4 (18.8‒22.2)	0.9	25.0	25.4 (25.0‒26.2)	0.5	21.2	20.4 (19.1‒22.1)	0.9	21.5	21.2 (19.0‒24.2)	1.1
Post-anus length (TL1)	31.2	30.7 (28.1‒33.9)	1.7	32.1	32.7 (30.9‒35.3)	1.7	32.4	34.4 (31.9‒37.9)	1.7	30.9	30.6 (27.0‒34.8)	1.6
Post-dorsal length (TL2)	18.0	18.1 (16.6‒22.8)	1.5	20.3	19.8 (19.2‒20.3)	0.5	20.4	19.7 (17.2‒23.8)	1.8	17.2	17.1 (14.4‒20.6)	1.5
Post-anal length (TL3)	15.0	16.0 (14.2‒18.6)	1.3	18.8	17.6 (15.3‒18.8)	1.3	18.0	16.8 (14.6‒19.1)	1.4	14.3	15.5 (12.4‒18.6)	1.6
Caudal peduncle depth	7.6	8.2 (6.7‒9.3)	0.5	8.4	8.4 (8.1‒8.9)	0.3	‒	7.4 (7.0‒7.8)	0.3	8.2	8.4 (7.7‒9.2)	0.4
Caudal fin length	32.3	32.0 (29.1‒36.3)	1.9	31.3	29.5 (27.2‒31.3)	1.9	‒	28.5 (25.7‒31.9)	1.9	28.6	30.2 (25.4‒35.3)	2.2

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 ).