Chaunax heemstraorum, Ho, Hsuan-Ching & Ma, Wen-Chun, 2016

Ho, Hsuan-Ching & Ma, Wen-Chun, 2016, Revision of southern African species of the anglerfish genus Chaunax (Lophiiformes: Chaunacidae), with descriptions of three new species, Zootaxa 4144 (2), pp. 175-194 : 182-186

Chaunax heemstraorum sp. nov.

New English name: Heemstras' frogmouth Figures 4 A–C; Tables 1–3

Holotype. SAIAB 82029 (163 mm SL), 24°35.3’S, 35°38.7’E, off Mozambique, 770–774 m, 12 Oct. 2007.

Paratypes. 8 specimens, 95.1–128 mm SL. MNHN 1977-0031 (1, 111), 22°16'8.4"S, 43°7'8.4"E, Madagascar, 195–200 m, 1 Dec. 1973 . SAIAB 13737 (5, 95.1–126), 3°26'S, 40°23'E, off Malindi, Kenya, 484 m, 11 Dec. 1980 . SAIAB 30332 (1 of 82, 128), 29°53'S, 31°25'E, off Durban , KwaZulu-Natal, South Africa, 410 m, 26 Aug. 1986 . SAIAB 49351 (1, 124), 34°27'S, 17°57.1'E, off West coast, South Africa, 333 m, 12 Jan. 1986 .

Non-types (*indicates specimens with meristic data taken). Madagascar: MNHN 1977-0023 (2, 69.6–82.1), 25°28'58.8"S, 46°46'1.2"E, 350–360 m, 30 May 1973 . MNHN 2014-1581 (1, 68.4), 12°52'28.8"S, 48°07'42"E, 558–592 m, 25 Jun. 2009. MNHN 2014-1883 (1, 31.9), 12°47'56.4"S, 48°11'16.8"E, 430–488 m, 2 Jul. 2009. South Africa: * SAIAB 3182 (3, 33.2–62.4), KwaZulu-Natal, 552 m, Jun. 1973 . SAIAB 4706 (2, 33.1–38.0), 33°33’S, 27°06’E, Great Fish Point , Eastern Cape, no date . SAIAB 28306 (1, 33.2), 34°29’S, 25°36.6’E, off South Coast, 438 m, 22 May 1988 . SAIAB 28510 (1, 34.1), 35°36.4’S, 22°2.0’E, off South coast, 172 m, 28 Sep. 1987 . * SAIAB 30332 (81 of 82, 37.1–83.4), 29°53’S, 31°25’E, off Durban , KwaZulu-Natal, 410 m, 26 Aug. 1986 . SAIAB 34821 (1, 37.2), 34°30’S, 25°36’E, South coast, KwaZulu-Natal, 1985 . SAIAB 35516 (1, 37.6), 34°13.8’S, 26°38.2’E, off Eastern Cape, 102 m, 3 Jun. 1990 . * SAIAB 49353 (1, 55.1), 37°05’S, 17°39’E, off West coast, 230 m, 9 Jul. 1986 . * SAIAB 49356 (1, 89.1), 34°24’S, 25°52’E, off South coast, 199 m, Oct. 1986 . SAIAB 87668 (3, 84.0–91.1), 29°42.3’S, 31°37.0’E, Tugela Deep , KwaZulu-Natal, 320 m, 5 May 2005 . Kenya: * SAIAB 14054 (6, 98.1–103), 3°49’S, 40°00’E, off Mombasa, Kenya, 455 m, 11 Dec. 1980 . SAIAB 14094 (1, 39.0), 3°26’S, 40°43’E, off Kilifi, Kenya, 770 m, 11 Dec. 1980 . Mozambique: * SAIAB 28513 (2 of 3), S of Maputo, Dec. 12 . SAIAB 189801 (1, 96.4), 26°10.2'S, 33°17.6'E, 505–509 m, 30 Sep. 2007. SAIAB 81820 (1, 68.1), 25°51.6’S, 33°17.1’E, 509–511 m, 3 Oct. 2007. SAIAB 82062 (2, 38.2–41.5), 23°32.3’S, 35°52.2’E, 539–553 m, 14 Oct. 2007.*SAIAB 98898 (1, 67.0), 12°25.6’S, 40°40.6’E, 408 m, 23 Nov. 2007. No data: *SAIAB 4711 (4, 99.2–121). SAIAB 4713 (4 of 5).

Diagnosis. A species of the C. abei species group with relatively slender body, a smaller head and slender tail. It can be distinguished from congeners by following combination characters: large green spots on dorsal surface; usually 3 neuromasts on upper preopercular series, 15–16 in pectoral series, 35–38 in lateral-line proper and 5 on caudal-fin base; 10–12 rakers on second gill arch; and 13 pectoral-fin rays.

Description. Morphometric and meristic data are provided in Tables 1–3.

Dorsal-fin rays III, 12; pectoral-fin rays 13 (13 or 14, modally 13); anal-fin rays 7; caudal-fin rays 9. Head length 2.5 (2.3–2.6) in SL; head width 6.7 (5.9–6.7) in SL, 2.6 (2.4–2.6) in HL; pre-dorsal length 2.1 (2.0–2.1) in SL; pre-gill opening length 1.7 (1.7–1.9) in SL; pre-preopercular length 3.8 (3.3–3.9) in SL, 1.5 (1.4–1.5) in HL; upper jaw 5.4 (4.9–5.4) in SL, 2.1 (2.0–2.1) in HL; illicial length 10.7 (10.7–16.6) in HL; eye diameter 4.4 (4.0– 4.6) in HL; post-dorsal-fin length 5.1 (4.7–5.6) in SL, 2.0 (1.8–2.3) in HL; post-anus length 2.9 (2.6–2.9) in SL, 1.1 (1.0–1.3) in HL; post-anal-fin length 5.6 (4.8–5.9) in SL, 2.2 (2.0–2.3) in HL; caudal-peduncle depth 4.9 (4.9–5.9) in HL; caudal-fin length 3.3 (3.3–3.5) in SL, 1.3 (1.3–1.4) in HL.

Head globular, skull elevated above rest of body posteriorly; trunk and tail robust, weakly compressed, tapering posteriorly to caudal-fin base; ventral surface of belly flattened; skin thick, loose and flaccid; interspace between eyes broad, convex; caudal peduncle short. Eyes rounded, directed laterally; covered by dermal membrane, broadly connected to adjacent skin, forming clear window.

Illicium relatively slender, its length less than eye diameter; esca depressed, forming large central plate bearing many dark brown cirri; second dorsal-fin spine close to illicium, embedded under skin and not detectable externally; third dorsal-fin spine situated at about midpoint of predorsal distance, embedded beneath skin. Illicial trough oval-shaped, slightly concave, uniformly narrow, its length about twice its width. Origin of soft dorsal fin slightly behind midpoint of body; pectoral fin emerging laterally near midpoint of body, slightly anterior to vertical through gill opening; pelvic fin on breast, well anterior to pectoral fin; anus situated just in advance of posterior fourth of body; anal-fin origin at posterior fifth of body, its tip nearly reaching caudal-fin base when depressed.

Nostrils anterior to eye; anterior nostril surrounded by fleshy membrane, its rim taller posteriorly than anteriorly; posterior nostril a circular depression; mouth wide, superior, its opening nearly vertical; lower jaw robust, protruding slightly in front of upper jaw; maxilla tapering, narrow dorsally, broadly expanded ventrally; blunt symphysial spine on symphysis of lower jaw.

Broad transparent membrane on first gill arch; first ceratobranchial well-connected to opercular wall, and first epibranchial entirely free of it; gill filaments present on second to fourth gill arches, two rows of gill filaments in second and third gill arches, single row of gill filaments on fourth gill arch; filaments on inner rows of third and fourth gill arches about two-thirds length of filaments on other arches; inner surface of fourth gill arch completely connected to body. Single row of 16 (14–16) rakers on 1st gill arch, 5 (4 or 5) on upper limb and 11 (10–12) on lower limb, 11 (10–12) rakers on outer row of 2nd arch, 11 (10–11) rakers on outer row of 3rd arch, and single row of 9 (8 or 9) rakers on 4th arch.

Interspaces of lateral-line neuromast complex slightly longer than its width; 3 (rarely 3–5, modally 3) pairs of short spines bridging each neuromast. Lateral-line neuromast counts: supraorbital (AB) 11 (10–12, modally 11); premaxillary (AC) 8; upper preopercular (BD) 3 (2–4, modally 3); infraorbital (CD) 6 (5–7, modally 6); lower preopercular (DG) 3 (3 or 4, modally 3); mandibular (EF) 6 (5 or 6); hyomandibular (FG) 3; pectoral (GH) 18 (13– 18, mainly 15 or 16); anterior lateral-line proper (BB') 4 (3 or 4, modally 4); supratemporal (BB) 6; and lateral-line proper (BI) 38 (38–42), including 5 (3–6, modally 5) on caudal-fin base.

Dorsal surface covered by simple, stout spinules, except for eye window, lips, distal fifth of dorsal surface and entire ventral surface of pectoral fin, distal half of dorsal surface and entire ventral surface of pelvic fin, entire anal fin and its base, membranes of dorsal fin, anus, and caudal-fin rays. Single row of spinules in front of illicial trough (naked medially in some smaller specimens). Ventral surface covered by slightly shorter, firm spinules. Jaws and body margin along lateral line densely covered with simple, stout cirri; cirri absent from head, jaws and ventral surface.

Coloration. When fresh holotype ( Fig. 4 A) with uniformly reddish color, other non-type and juveniles ( Fig. 4 B–C) with dorsal surface covered with medium-sized irregular green spots on reddish background; pale ventrally. When preserved, dorsal surface with irregular gray spots on uniformly pale background or spots faded; pale ventrally. Cirri on esca dark brown. Gill chamber, buccal cavity and gill rakers pale; peritoneum black.

Size. The largest known specimen has a length of 163.0 mm SL. This is most likely a small species compared to other congeners.

Distribution. Known from the southern Africa, off South Africa (including the western coast), Mozambique and Kenya ( Fig. 3 ). Bathymetric range 102– 774 m.

Etymology. We are pleased to name this species after Dr. Philip and Elaine Heemstra, who offered great hospitality and assistance when the first author worked in the SAIAB fish collection.

Remarks. Chaunax heemstraorum sp. nov. is most similar to C. nudiventer in having large spots on its dorsal surface, slender dermal spinules and a relatively slender body. It differs from C. nudiventer in having its ventral surface covered by spinules (vs. a large naked area on ventral surface), modally 13 pectoral-fin rays (vs. modally 14), modally 3 neuromasts in BD (vs. modally 4 or 5), lacking melanophores on its ventral surface in smaller specimens (vs. densely covered by tiny melanophores in specimens smaller than 100 mm SL) and relatively few neuromasts on lateral-line proper (37–42 vs. 39–50).

It is also similar to Chaunax latipunctatus from the southeastern Pacific but differs in having a relatively short upper jaw (18.4–20.3% SL vs. 20.8–27.5% SL), relatively long post-anal length (17.0–20.8% SL vs. 13.0–16.7% SL), modally 13 pectoral fin rays (vs. modally 14), modally 11 neuromasts on supraorbital (vs. modally 12), modally 6 (vs. 7 or 8) on infraorbital; modally 3 (vs. 4 or 5) on hyomandibular.

Chaunax heemstraorum sp. nov. can be easily distinguished from C. atimovatae by its coloration, relatively large eye (8.5–10.9% vs. 6.0–8.5%), relatively long post-anal length (Tail length 1, 34.4–38.8% SL vs. 27.3–33.9% SL) and post-anal length (Tail length 3, 17.0–20.8% vs. 13.2–16.0% SL); modally 3 neuromasts in the upper preopercular (vs. 2), 13–18 in the pectoral (vs. 11–14) and 37–42 in the lateral-line proper (vs. 31–37).

Ho & Shao (2010:60) mentioned that two unidentified specimens similar to C. nudiventer were collected from the western Indian Ocean. Although these two specimens are most likely conspecifics with C. heemstraorum sp. nov., they have only 11–12 neuromasts in the pectoral series and 34–36 in the lateral-line proper, fewer than those of C. heemstraorum sp. nov. Their identity is still doubtful at present.

Chaunax heemstraorum sp. nov. is one of two Chaunax species occurring on both sides of southern Africa, e.g. southeastern Atlantic and southwestern Indian oceans; on the west coast of South Africa, it has been found to north of 32°29'S. Another species occurring in the southeastern Atlantic is C. suttkusi , which is restricted to the Angolan region, north of about 11°45'S. These species appear not to occur sympatrically.

Pectoral-fin rays AB AC CD n 10 11 12 13 14 n 10 11 12 8 5 6 7

apus 32 1 12 19 37 35 2 38 9 25 4

atimovatae 34 2 32* 38 37* 1 38* 20 18*

flammeus 2 2 2 2 2 2

heemstraorum 70 68* 2 86 2 80* 4 86* 6 68* 12

hollemani 10 6* 4 10 10 * 10* 10*

penicillatus 10 4 6 10 6 4 10 8 2

russatus 10 6 4 10 6 4 8 2 8

suttkusi 16 1 2 11 2 16 16 16 12 4

BD DG EF FG

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

apus 38 3 35 38 34 4 37 1

atimovatae 38 38* 38* 37* 1 38*

flammeus 2 2 2 2 2

heemstraorum 86 7 76* 3 82* 4 84* 2 86*

hollemani 10 10* 10* 10* 10*

penicillatus 10 10 10 10 10

russatus 10 10 10 8 2 8 2

suttkusi 16 2 14 5 11 14 1 1 2 8 6 ……continued on the next page GH BB ‵ BB

n 10 11 12 13 14 15 16 17 18 3 4 5 n 6. apus 36 19 12 3 2 2 32 1 19 19. atimovatae 38 6 18 10 4* 37* 1 19 19 *. flammeus 2 2 2 1 1. heemstraorum 86 1 16 32 25 6 6 * 2 84* 43 43*. hollemani 10 1 5 * 1 3 8* 2 5 5*. penicillatus 10 2 8 8 2 5 5. russatus 10 3 4 1 2 10 5 5. suttkusi 16 4 2 8 2 2 14 8 8

BI

n 30 31 32 33 34 35 36 37 38 39 40 41 42 43. apus 38 1 4 7 3 5 7 6 2 3. atimovatae 30 4 2 4 10 8 * 6 4

. flammeus 2 2

. heemstraorum 64 2 22 * 14 20 14 14. hollemani 4 3* 3* 0 2 1 1

. penicillatus 10 2 2 2 2 2

. russatus 10 4 2 4

. suttkusi 16 2 6 4 0 2 2

Figures

FIGURE 3. Distribution map of Chaunax atimovatae sp. nov. (red squares), Chaunax heemstraorum sp. nov. (green circles) and Chaunax hollemani sp. nov. (black star).

FIGURE 4. Chaunax heemstraorum sp. nov. A. SAIAB 82029, holotype, 163 mm SL. B. SAAIB 81820, non-type, 68.1 mm SL. C. SAIAB 82062, non-type, juvenile, 41.5 mm SL.