Malthopsis bradburyae, Ho, Hsuan-Ching, 2013

Ho, Hsuan-Ching, 2013, Two new species of the batfish genus Malthopsis (Lophiiformes: Ogcocephalidae) from the Western Indian Ocean, Zootaxa 3716 (2), pp. 289-300 : 290-294

Malthopsis bradburyae n. sp.

Common name: Bradbury’s triangular batfish Figs. 1 A–C, 2A–E; Table 1

Holotype. CAS 227226 (72.4 mm SL), R/V Anton Bruun, cruise 9, station 22, 6°51’S, 39°54’E, Tanzania, Western Indian Ocean, 100 m, coll. A. H. Fehlmann, 19 Nov. 1964.

Paratypes. CAS 39631 (7 specimens, 35.6–70.9 mm SL) and NMMB-P17824 (1, 59.0), collected with the holotype.

Diagnosis. A species of Malthopsis distinguished by the following combination of characters: body covered by blunt, smooth bucklers and numerous prickles; rostrum moderately long (mean 7.7% SL) and stout, with a broad base, directed forward horizontally; three irregular rows of bucklers on top of head; ventral surface of disk densely covered by prickles and scattered small bucklers, with some slightly larger bucklers on breast; subopercular buckler blunt, without enlarged spines; orbit small (mean 12.4% SL); interorbital space broad (mean 8.5% SL), forming a deep groove; OD/RL = 1.3–2.2; OD/IO = 1.3–1.7; and anal fin reaches or nearly to the caudal-fin base when fully depressed.

Description. Morphometric and meristic data are provided in Table 1 . Values are given for the holotype, followed by the range and/or mean values of all types in parentheses.

Body depressed, disk markedly triangular in dorsal view, head elevated above rest of disk; tail base broad; caudal peduncle thick and broad, semi-cylindrical, flattened ventrally and tapering posteriorly; rostrum thick and pointed, directed forward horizontally ( Figs. 2 A–B), with a broad base, distinctly overhanging illicial cavity and mouth; rostrum moderately long, 6.2% SL (6.2–9.4% SL, mean 7.7% SL), shorter than orbital diameter; orbit small, 13.5% SL (11.1–13.5% SL, mean 12.4% SL), eyes directed dorsolaterally; no pupillary operculum; interorbital space wide 8.1% SL (7.6–9.8% SL, mean 8.5% SL), forming a deep groove ( Fig. 2 A); frontal ridges strongly convex, elevated above the rostral base ( Fig. 2 B).

Illicial cavity large, triangular, higher than wide; esca a single bulb, bearing 2 small cirri on dorsal margin; mouth small, terminal; small villiform teeth on jaws forming narrow bands, those on fifth ceratobranchial forming 2 large, elongated patches close together; teeth on vomer and palatines in quadrangular patch.

Dorsal disk squamation well developed, consisting mainly of blunt, medium-sized, smoothly conical bucklers ( Fig. 2 C); interspaces between large bucklers covered by small bucklers and prickles; bucklers on frontal ridge small and blunt, 2 enlarged preorbital bucklers which overlap front border of orbit, upper buckler larger, fused to base of rostrum; usually 4 (4–5) smaller, subequal-sized blunt bucklers on supraorbit ( Fig. 2 B), not well-elevated from the margin; interorbital space densely covered by small bucklers; supraorbital membrane covered with several irregular rows of small bucklers on upper margin of orbit, naked elsewhere. Dorsal surface of head covered by about 3 irregular rows of 3 or 4 slightly larger bucklers on each row, with many smaller ones adjacent ( Fig. 2 A), followed by two irregular median rows of large bucklers predorsally, ending before dorsal-fin origin as a rectangular cluster of 5 large bucklers ( Fig. 2 C); shoulder with small scattered naked areas, extending to gill openings and base of pectoral elbows.

Disk margin with cluster of suborbital bucklers anteriorly, forming 3 well-defined rows posteriorly; uppermost row of bucklers elevated, broad based; middle and lower rows of bucklers depressed and associated with lateral line, all blunt; bucklers on middle row directed laterally, lower row directed ventrally and inferior; neuromasts well defined. Subopercular buckler enlarged, extended slightly beyond disk margin laterally; terminating on uppermost and middle rows of disk-margin bucklers; small spinelets (variable in size and coverage) at tip of subopercular buckler; two well-defined, blunt, post-subopercular bucklers ( Fig. 2 D). Pectoral-fin base at rear of disk; covered dorsally with well-developed bucklers; 4 (3–5) fine bucklers over anterior fin ray, naked elsewhere.

Dorsal surface of tail strongly armoured, entirely covered with large blunt bucklers; a row of 4–5 large dorsolateral bucklers, extending from last pair of predorsal bucklers below dorsal fin; a longer, highly irregular, semi-oblique row of slightly smaller bucklers extending along lateral margin of peduncle to caudal-fin base; a single irregular row of flattened bucklers on dorsal midline before caudal fin; dorsal tail rows uniting to form a single, slightly elevated buckler at caudal-fin base. Lateral margin of tail with two rows of small, low bucklers associated with lateral line, similar in appearance to bucklers of disk margin.

Ventral surface of disk predominantly covered with small, flat bucklers; no apical spines on these bucklers; belly densely covered with prickles and scattered small bucklers, some slightly larger on breast than posteiorly ( Fig. 2 E); rear margin of anus surrounded by 5 (4–5) blunt bucklers; large naked area outside gill chamber; ventral surface of tail with a single regular row of blunt bucklers on each side, coalescing to bulbous buckler at caudal-fin base.

Fins generally naked, without bucklers, sometimes with small bucklers on rays near caudal-fin base; interradials of pectoral fins thin, transparent; dermal cirri short, thin, flap-like, present on disk margin and lateral sides of tail and associated with lateral-line neuromasts. Anal fin reaches to or slightly short of caudal-fin base when fully laid back.

Coloration. Fresh color unknown. Preserved specimens ( Figs. 1 A, C) uniformly creamy yellowish. Holotype and some paratypes with very fine brown reticulations on dorsal surface.

Size. A medium-sized species. The largest adult is 72.4 mm SL.

Distribution. Known only from the type series taken off Tanzania at a depth 100 m.

Etymology. The species is named after the late Dr. Margaret G. Bradbury, in recognition of her great contribution to our knowledge of batfishes, and her friendship.

Remarks. Malthopsis bradburyae n. sp. belongs to a species group with the ventral surface densely covered by minute prickles (e.g., M. kobayashii , M. tiarella , M. asperata and M. gnoma ). It differs from M. tiarella by having 5–6 dorsal-fin rays (modally 5, vs. 6–7 in M. tiarella ), bucklers on body surface blunt and smooth (vs. pointed and rough), and lacking brown bands on the caudal peduncle (vs. bands present on peduncle); from M. kobayashii in its rostral spine directed forward horizontally (vs. directed forward and upward), in having a relatively wide interorbital space (7.6–9.8% SL vs. 6.0–7.5% SL), and bucklers on body surface blunt and smooth (vs. relatively pointed and rough); from M. asperata in having all bucklers blunt (vs. pyramid-like bucklers with spinelets); and from the western Atlantic species, M. gnoma , in lacking gill filaments on the fourth gill arch (vs. filaments on the fourth gill arch); and in the rostral spine directed forward horizontally (vs. upward and forward).

It is also similar to M. annulifera from the western Pacific in having the rostral spine directed forward horizontally and principal bucklers on the body are relatively flat and smooth. It can be distinguished from M. annulifera in having ventral surface covered by prickles (vs. no prickles); blunt subopercular bucklers without well-developed spines (vs. 1 well-developed spine directed forward), and lacking ring marks on the dorsal surface (vs. few to more than 20 rings present).

Figures

FIGURE 1. Malthopsis bradburyae n. sp. A. Holotype, CAS 227226, 72.4 mm SL, dorsal view, preserved. B. holotype, ventral view, preserved. C. Paratype, CAS 39631, 1 of 7, 70.9 mm SL, dorsal view, preserved.

FIGURE 2. Close-up view of body portions of Malthopsis bradburyae n. sp., from the holotype. A. Dorsal view of head. B. Lateral view of head. C. Dorsal view of dorsal surface between dorsal fin and cranium. D. Dorsal view of right portion of disk. E. Ventral view of surface of central disk. Anterior to left in Figs. A, D, E. Anterior to right in Figs. B, C. Not to scale.

Tables

TABLE 1. Morphometric and meristic data of two new Malthopsis species described in present study. Pectoral-fin rays are counted on both sides.

	M. bradburyae n. sp.	M. austrafricana n. sp.
	Holotype All types	Holotype All types
SL	72.4 35.6–72.4 (n = 9)	70.0 45.2–84.0 (n = 17)
% SL	Mean (Range) SD	Mean (Range) SD
Head length	27.2 27.8 (26.0–29.5) 1.1	27.4 27.1 (24.8–30.3) 1.3
Head width	21.5 22.5 (20.8–25.0) 1.2	22.9 23.0 (20.6–25.8) 1.4
Head depth	22.8 23.1 (21.2–25.9) 1.5	21.4 22.2 (19.8–24.0) 1.4
Orbital width	13.5 12.4 (11.2–13.5) 0.8	12.1 12.5 (10.7–14.5) 0.9
Interorbiral width	8.1 8.5 (7.6–9.8) 0.7	9.4 8.4 (7.4–9.7) 0.7
Rostral length	6.2 7.7 (6.2–9.4) 1.1	9.4 8.3 (6.0–10.7) 1.7
Predorsal length	66.2 67.5 (65.3–69.8) 1.8	64.3 12.9 (10.7–14.5) 1.0
Preanus length	53.0 55.3 (53.0–58.2) 1.9	54.3 66.5 (63.8–71.4) 2.0
Preanal length	79.8 81.0 (77.5–83.0) 1.8	82.4 54.8 (52.6–57.5) 1.5
Disk margin length	43.0 44.1 (40.1–47.2) 2.7	44.9 80.5 (78.1–82.9) 1.3
Mouth width	14.4 14.4 (13.1–15.9) 0.9	12.9 44.5 (39.6–48.1) 2.7
Dorsal-fin length	18.9 18.6 (16.8–20.2) 1.2	17.4 22.3 (19.6–24.8) 1.4
Anal-fin length	15.1 17.7 (15.1–20.5) 1.9	14.3 17.4 (14.3–19.3) 1.4
Pectoral-fin length	22.0 22.5 (20.9–24.2) 1.1	22.6 17.7 (14.3–20.3) 1.7
Caudal-fin length	25.8 26.1 (24.0–29.2) 1.9	25.7 25.2 (23.1–27.3) 1.3
Meristics	Value (Frequency)	Value (Frequency)
Dorsal-fin rays	5 5 (7), 6 (2)	5 5 (12), 6 (5)
Pectoral-fin rays	12/13 11 (2), 12 (15), 13 (1)	13/13 12 (30), 13 (4)
Anal-fin rays	3 3 (3), 4 (5)	4 3(2), 4 (15)