Chaunax nudiventer, Ho, Hsuan-Ching & Shao, Kwang-Tsao, 2010

Ho, Hsuan-Ching & Shao, Kwang-Tsao, 2010, A new species of Chaunax (Lophiiformes: Chaunacidae) from the western South Pacific, with comment on C. latipunctatus, Zootaxa 2445, pp. 53-61 : 54-60

publication ID	https://doi.org/ 10.5281/zenodo.195029
DOI	https://doi.org/10.5281/zenodo.6205492
persistent identifier	https://treatment.plazi.org/id/6F5787A2-9642-FF84-FF69-FCE1FEE2F868
treatment provided by	Plazi
scientific name	Chaunax nudiventer
status	sp. nov.

Treatment

Chaunax nudiventer View in CoL sp. nov.

New English name: Naked-belly Coffinfish ( Figs. 1 View FIGURE 1 A, 2A–C, 3, 4A–B; Tables 1–2)

Holotype. NSMT P95084 (271 mm), R/V Kaiyo-maru, trawl 22, 26°01.7’S, 179°02.3’W, South Fiji Ridge, 538–620 m, 16 Jan. 1977.

Paratypes. MNHN 2002–0178 (2 specimens, 54–120 mm) and MNHN 2002–0229 (1, 131), Campagne Biocal, sta. cp67, 24°91’S, 168°36’E, 500–510 m, 3 Sep. 1985. MNHN 2002–1642 (6, 85–166) and MNHN 2002–1649 (3, 113–129), 24°55’S, 168°21’E, New Caledonia, 500–610 m, 28 Oct. 1986. MNHN 2002–0207 (1, 59), Campagne Smib 4, sta. dw39, 24°93’S, 168°35’E, 560 m, 7 Mar. 1989. MNHN 2002–0228 (2, 48– 155), Campagne Chalcal 2, sta. dw72, 24°90’S, 168°36’E, 527 m, 28 Oct. 1986. MNHN 2002–0240 (1 of 2, 127), Campagne Chalcal 2, sta. ch7, 29°91’S, 168°35’E, 494–590 m, 29 Oct. 1986. MNHN 2003–1542 (3), Campagne Lithist, sta. cp9, 24°86’S, 168°35’E, 518–540 m, 11 Aug. 1999. MNHN 2004–2593 (1, 60), Campagne Norfolk 2, sta. dw2080, 25°34S, 168°30’E, 764–816 m, 27 Oct. 2003. MNHN 2004–2608 (2, 52– 53), Campagne Norfolk 2, sta. cp2060, 24°65’S, 168°63’E, 282–600 m, 25 Oct. 2003. MNHN 2004–2657 (1, 54), Campagne Norfolk 2, sta. dw2074, 25°40’S, 168°31’E, 623–691 m, 27 Oct. 2003. MNHN 2004–2679 (5, 33–66), Campagne Norfolk 2, sta. cp2088, 24°96'S, 168°35'E, 627–1089 m, 28 Oct. 2003. MNHN 2004–2848 (1, 36), Campagne Norfolk 2, sta. cp2118, 23°36’S, 168°00’E, 383–393 m, 1 Nov. 2003. NMNZ P29205 (1, 188), 24°S, 168°E. NSMT P90583 (1, 198), NSMT P78819 (1, 262), NSMT P78820 (1, 243), and NMST P78821 (1, 201), collected with holotype.

Diagnosis. A species of the C. abei species group that differs from its congeners in having large spots on the dorsal surface ( Fig. 2 View FIGURE 2 A–C); a largely naked area on abdomen ( Fig. 3 View FIGURE 3 ); a relatively short head (27.0–29.8% SL) and a relatively long tail (tail length 1=34.0–35.6% SL), reflected in the relatively elongated body; dermal spines on body surface all simple, relatively slender and elongated ( Figs. 4 View FIGURE 4 A–B); and relatively high lateral line neuromast counts, 39–50 (mainly 41–43) in lateral line proper, 3–5 (mainly 4) in upper peropercular series, and 15–19 (mainly 16–17) in pectoral series, which is well extended beyond pectoral fin base.

Description. Head globular, skull slightly elevated posteriorly; trunk cylindrical, slightly compressed, tapering posteriorly; venter relatively flattened; skin loose and flaccid; interorbital space broad; eyes directed dorsolaterally, covered by a dermal membrane broadly connected to adjoining skin, forming a clear “window”; illicial trough oval shaped, located at anterior portion of interorbital space, about equal to eye diameter; two pairs of nostrils anterior to eyes; mouth relatively wide, terminal, its opening nearly vertical; lower jaw slightly protruding beyond upper jaw; maxilla tapering above, broad below; symphyseal spine on lower jaw; teeth small, villiform, slightly curved on both jaws; teeth present on vomer, palatines and fifth ceratobranchial; oral cavity large; 11–12 rakers on second gill arch; gill filaments present on first, second and third gill arches.

C. nudiventer n. sp. C. latipunctatus

Holotype Holotype + Paratypes (n=15) Non– type (n=9)

SL (mm) 271 110–271 95–132

Morphometrics (% SL) Range (Average) SD Range (Average) SD Head length 38.0 37.2–42.5 (39.1) 1.4 39.0–44.6 (41.3) 1.5 Pre–preopercular length 25.3 23.9–27.5 (26.0) 1.6 28.4–35.1 (30.3) 2.0 Pre–dorsal length 45.6 45.6–50.5 (48.2) 1.2 49.5–57.4 (52.0) 2.5 Illicial length 3.6 3.1–4.5 (3.9) 0.5 3.4–4.3 (3.9) 0.4 Illicial trough length 5.0 5.0–6.1 (5.3) 0.5 6.1–8.0 (7.2) 0.7 Pre–gill opening length 57.1 55.4–61.2 (58.5) 2.0 60.6–69.3 (64.0) 2.7 Upper jaw length 20.0 17.1–21.2 (18.9) 1.4 20.8–27.5 (22.8) 1.9 Caudal fin length 25.0 22.6–29.9 (27.2) 2.3 21.0–35.1 (28.1) 4.0 Tail length 1 (Post–anus) 33.3 31.9–35.7 (33.9) 1.4 28.9–37.6 (32.8) 2.9 Tail length 2 (Post–dorsal fin) 16.2 16.0–21.8 (18.3) 1.3 15.7–19.7 (17.5) 1.3 Tail length 3 (Post–anal fin) 19.1 18.0–22.3 (20.2) 1.1 13.0–16.7 (14.8) 1.3 Gill openings located at axil of pectoral elbow; pectoral fin attached at margin of lateral body and oriented horizontally; pectoral fin fan-shaped covered by thick skins, middle rays longest; pelvic fin much smaller than pectoral fin, located ventrolaterally; anterior pelvic fin ray longest, with thick membrane.

Illicium anterior to eye; esca with a “medial tongue” (sensu Le Danios, 1979) bearing numerous cirri at anterior surface; second dorsal spine small, located at base of illicium and embedded under skin; third dorsal spine located at midpoint between mouth and origin of second dorsal fin, embedded under skin; second dorsal fin comprises 10–11 soft rays, its origin about opposite that of anus; first ray of second dorsal fin very short, sometimes covered by skin; posterior rays either simple or bifurcated; pectoral fin with 13–14 rays; anal fin with 6 fin rays, its origin below fifth dorsal fin ray, fin rays covered by thick skin, when depressed not reaching caudal fin base; caudal fin truncate or slightly rounded posteriorly, with 8 rays, outermost two rays unbranched, remainder branched; vertebrae 19 (6 paratypes examined), including the hypural plate.

Network of open sensory canals on body surface as described in Caruso (1989). Three simple spines on each side of neuromast ( Fig. 1 View FIGURE 1 A). Lateral line neuromast counts for type series ( Table 2): 10–12 (mainly 10– 11) in supraorbital series (AB); 7–8 (mainly 7) in premaxillary series (AC); 3–5 (mainly 4) in upper preopercular series (BD); 2–4 (mainly 3) in lower preopercular series (DG); 5–7 (mainly 7) in infraorbital series (CD); 3–4 (mainly 3) in hyomandibular series (FG); 15–19 (mainly 16–17) in pectoral series (GH); and 39–50 (mainly 41–43) in lateral line proper ( BI, including those on caudal fin).

Dermal spines needle-like, slightly recurved distally and relatively dense in arrangement ( Fig. 4 View FIGURE 4 A–B), covering entire body surface except for ventral surface, eye window, pectoral and pelvic fins, interradial membranes of dorsal and caudal fins, illicial trough, and gill openings. Ventral surface with a large naked area as shown in Fig. 3 View FIGURE 3 . Small flap-like appendages along chin and lateral body associated with lateral line; both jaws densely covered by short cirri.

Size up to 271 mm SL in type series.

Coloration. In fresh-caught specimen, dorsal surface uniformly bright red with numerous large deep-red spots; spots varying in shape and size, from about half of to equal to eye diameter ( Fig. 2 View FIGURE 2 B). In preserved specimens, background uniformly creamy white with large gray spots on dorsal surface, shape and size as mentioned above ( Fig. 2 View FIGURE 2 A–C), these spots may fade out with time; oral cavity pale, peritoneum black; appendages associated with lateral line bright white in some preserved specimens.

Distribution. Known from the type series collected in the western South Pacific ( Fig. 5 View FIGURE 5 ) at depths of 282– 1089 m.

P fin rays AB AC

n 13 14 15 n 10 11 12 13 14 15 16 n 6 7 8

C. nudiventer 48 11 37* 48 14 32* 2 48 27 21* C. latipunctatus 54 6 36* 12 52 40* 8 3 – 1 40 1 19 * 28

BD CD DG

n 2 3 4 5 n 5 6 7 8 n 2 3 4 5

C. nudiventer 48 7 30 11* 48 2 18 28* 48 2 38* 8 C. latipunctatus 56 5* 48 3 56 2 36* 18 56 1 * 28 26 1

FG GH

n 3 4 5 6 n 12 13 14 15 16 17 18 19

C. nudiventer 48 46* 2 48 4 17 17* 7 3*

C. latipunctatus 56 18* 36 2 56 1 11* 21 16 7

n 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 C. nudiventer 48 5 3 7 14* 9* 2 1 1 2 3 – 1 C. latipunctatus 54 1 2 5 10* 9 7 3 7 5 2 2 1 2

Etymology. From the Latin nudus (naked) and venter (abdomen), in reference to the naked area on the abdomen in this species.

Remarks. Chaunax nudiventer is placed in the C. abei species group, having 3 spines on each side of lateral line neuromast ( Fig. 1 View FIGURE 1 A), spots on dorsal surface, no filaments on dorsal surface of head, and flap-like cirri on lateral body. Chaunax nudiventer can be easily distinguished from its congeners except for C.

latipunctatus Le Danois, 1984 View in CoL (see comments on this species below) in having a large naked area on its abdomen ( Fig. 3 View FIGURE 3 ) and relatively large dorsal spots, about half of to equal to eye diameter.

Two other specimens, ZMMU 21656 (80 mm SL) and USNM 394324 (36 mm SL), also have a naked area on their abdomen. However, the lateral line neuromast counts of pectoral series (11–12) and lateral line proper (34–36) are slightly less than those for the type series of C. nudiventer View in CoL . Moreover, both specimens were collected from the western Indian Ocean. These two specimens may represent an undescribed species but more specimens are needed for further study.

Comments on C. latipunctatus Le Danois, 1984 ( Figs. 6 View FIGURE 6 A–B). The type series of C. latipunctatus (holotype and one paratype) and 74 additional specimens were examined. Morphometric and meristic data are included in Table 1 and Table 2.

The collecting data of type series was originally entered as “Galápagos Is., Exped. Ikhtiander, 25°00’S, 88°27'W – 99°26'W, 345–770 m, Oct. 1979 ”. According to the Russian vessel and station data provided by Sazonov and Iwamoto (1992), however, the type series of Chaunax latipunctatus was collected from Sala y Gomez Ridge by R/V Ikhtiander in the trawl number 50–57 of the 5th cruise during 24–31 Oct. 1979. The collecting data of these type series is revised accordingly: Holotype: MNHN 1984–0096 (86 mm SL), R/V Ikhtiander, Sala y Gomez Ridge, cr. 5, tr. 50–57, 25˚00’W–25˚46’S, 88˚27’W–99˚39’W, 345–770 m, 24–31, Oct. 1979. Paratype: MNHN 1984–0097 (1 specimen, 105 mm SL), same data as holotype.

The type series of C. latipunctatus and some HUMZ specimens all have scattered spines on the ventral surface. Other HUMZ specimens have a large ventral naked area similar to that of C. nudiventer . The spines on the ventral surface become fewer with body size in C. latipunctatus .

Chaunax latipunctatus belongs to the C. abei species group in having three spines on each side of lateral line neuromast ( Fig. 1 View FIGURE 1 B) and is most similar to C. nudiventer . but differs in having dermal spines that are relatively short and apart ( Figs. 4 View FIGURE 4 C–D); a relatively long head (28.4–35.1% vs. 37.2–42.5% SL); relatively long pre-gill opening length (60.6–69.3% vs. 55.4–61.2% SL); relatively long upper jaw (20.8–27.5% vs. 17.1–21.2% SL); and different lateral line neuromast counts: supraorbital series (AB) mainly 12 (vs. 11), upper preopercular (BD) mainly 4 (vs. 3), hyomandibular series (FG) mainly 4–5 (vs. 3), pectoral series (GH) mainly 13–15 (vs. 16–17), and lateral line proper ( BI) 33–40 (vs. 39–50). Furthermore, C. latipunctatus appears to be restricted to the eastern South Pacific, whereas C. nudiventer . is so far only known from the western South Pacific ( Fig. 5 View FIGURE 5 ). The bathymetric ranges are similar in both species.

It is notable that there are two females (104 mm SL and 132 mm SL) with large ovaries and free eggs probably approaching terminal stage, three females (73–97 mm SL) with large ovaries and immature eggs, and two males (95 mm SL and 118 mm SL) with large testes that measured more than 10% SL. The mature size of C. latipuncatatus is about 90–100 mm SL, relatively small compared to all other species (Ho, unpublished data). In addition, all examined specimens do not exceed 135 mm SL. Thus, this species is considered to be a small species.

Materials examined for Chaunax latipunctatus (76 specimens, 57–135 mm SL): MNHN 1984–0096, holotype (1, 86). MNHN 1984–0097, paratype (1, 105). IOAN 2078 (10, 67–80), R/V Professor Shtokman, cr. 18, sta. 2018, 25˚08’S, 99˚27’W, 730–790 m, bottom trawl, 7 May 1987. IOAN 2079 (1, 69), R/V Professor Shtokman, cr. 18, sta. 1964, 24˚56’S, 88˚33’W, 580– 564 m, bottom trawl, 30 Apr. 1987. IOAN 2080, IOAN 2081, IOAN 2082 (42, 57–120), R/V Professor Shtokman, cr. 18, 24˚S–26˚S, 88˚W–100˚'W, 545–800 m, bottom trawl, Apr.–May 1987. IOAN 2083 (1, 65), R/V Professor Shtokman, cr. 18, sta. 1965, 24˚59’S, 88˚29’W, 545–562 m, bottom trawl, 30 Apr. 1987. HUMZ 164450 (1, male, 95); HUMZ 164451 (1, 109); HUMZ 164452 (1, male, 118); HUMZ 164453 (1, 135); HUMZ 164454 (1, 67); HUMZ 164470 (1, 72); HUMZ 164533 (1, 98); HUMZ 164534 (1, 92); HUMZ 164535 (1, 73); HUMZ 164536 (1, 62); HUMZ 164572 (1, 120); HUMZ 164573 (2, 80–89); HUMZ 164574 (1, 83); HUMZ 164575 (1, female, 85); HUMZ 164576 (1, female, 105); HUMZ 164770 (1, female, 73); HUMZ 164771 (1, male, 91); HUMZ 164772 (1, female, 97); HUMZ 166560 (1, 103); all collected from 25˚30’S, 90˚18’W, Sala y Gomez Ridge, 576–578 m, 18 Oct. 1999.