Malthopsis parva, Ho, Hsuan-Ching, Roberts, Clive D. & Shao, Kwang-Tsao, 2013

Ho, Hsuan-Ching, Roberts, Clive D. & Shao, Kwang-Tsao, 2013, Revision of batfishes (Lophiiformes: Ogcocephalidae) of New Zealand and adjacent waters, with description of two new species of the genus Malthopsis, Zootaxa 3626 (1), pp. 188-200 : 192-195

Malthopsis parva sp. nov.

New English name: Arrowhead batfish Figs. 4 A–E, 5A–D; Table 1

Holotype. NMNZ P.017180 (46.4 mm SL), RNZFA Tui, stn. AUZ 0 11, 30° 45.0' S 173° 57.0' E, Three Kings Ridge, extended continental shelf, outside NZ EEZ, beam trawl, 537–677 m, 0 6 Jul. 1962.

Paratypes. 39 specimens, 27.0- 51.1 mm SL. CSIRO H6031-01(1, 51.1), NORFANZ cruise, R/V Tangaroa , TAN 0 308, stn. 66, 3 1 °45.33' S, 159°21.34' E, Tasman Sea, Lord Howe Rise, SE of Lord Howe Island, benthic sled, 565–960 m, 23 May 2003. NMNZ P.023916 (1, 41.5), NZOI K830, 29° 11.50' S – 177° 53.50' W, Kermadec Ridge, New Zealand, 545 m, 26 Jul. 1984. NMNZ P.029067 (4, 22.2–35.5), CSIRO H.7367-01 (2, 32.0–34.0), MNHN 2012-0216 (2, 28.0–40.0), NMMB-P10459 (2, 25.6–28.8), USNM 406843 (2, 32.0–33.0), N.O. Alis, Beryx 11 stn. 8, 24°53.15'S, 168°21.55'E, 'Seamount B', northern Norfolk Ridge, south of New Caledonia, beam trawl, 540–570 m; 15 Oct 1992, coll. C. D. Roberts & C. D. Paulin. NMNZ P.029116 (6, 20.3–39.4) N.O. Alis, Beryx 11 stn. CP7, 24°55.50'S, 168°21.45'E,'Seamount B', northern Norfolk Ridge, south of New Caledonia; bottom trawl, 540–670 m, 15 Oct 1992, coll. C. D. Roberts & C. D. Paulin. NMNZ P.029203 (17, 27.0–37.2, 3 stained), N.O. Alis, Beryx 11 stn. CP7, 24°55.5'S, 168°21.45'E, 'Seamount B', northern Norfolk Ridge, south of New Caledonia, 15 Oct 1992, coll. C. D. Roberts & C. D. Paulin. NMNZ P.029294 (1, 34.5), N.O. Alis, Beryx 11 stn. 32, 23°38.20'S, 167°43.58'E, Stylaster Seamount, New Caledonia, beam trawl, 420–460 m, 18 Oct 1992, coll. C. D. Roberts & C. D. Paulin. NMNZ P.035192 (1, 32.0), R/V Tangaroa I, NZOI K804, 29° 14.80'S, 177°49.60'W, Kermadec Ridge, New Zealand, 590 m, Jul 1974. NMNZ P.035194 (2, 40.0–41.4); R/V Tangaroa I, NZOI K830, 29°11.5'S, 177°53'W, Kermadec Ridge, New Zealand, 545 m, Jul 1974.

Non-type: NMNZ P.027540 (1, 39.4, in poor condition), N.O. Alis, Beryx 2 stn. 2, 24°53’S, 168°22.3’E, 'Seamount B', northern Norfolk Ridge, south of New Caledonia, 23 Oct 1991, coll. C. D. Roberts.

Diagnosis. A member of Malthopsis with a fully naked ventral surface and interspaces of principal bucklers on dorsal surface lacking dermal spinules. It is distinguished from congeners by having 5–6 (mainly 6) dorsal-fin rays; 13 pectoral-fin rays; the subopercular buckler blunt, with a stout anterior-directed spinelet usually present; rostral spine directed rather more upward than forward; relatively few and loosely arranged bucklers; all bucklers blunt; appressed anal fin reaches caudal fin base. In addition, it is the smallest species of the genus reaching 51.1 mm SL in adults.

Description. Morphometric and meristic values are provided in Tables 1. Body depressed, disc markedly triangular in dorsal view, cranium elevated above surface of other parts of disc; caudal peduncle cylindrical, tapering posteriorly, ventral surface slightly flattened; rostral small and blunt, directed rather more upward than forward ( Fig. 5 B), its length much less than half of eye diameter; eye median in size (14.3–17.5% SL, mean=15.8% SL), directed dorsolaterally; no pupillary operculum; interorbital space relatively narrow (4.3–7.0% SL, mean=5.4% SL), slightly concave, forming a groove between frontals ( Fig. 5 A); illicial cavity a small triangular cave, its width equal to its height; esca a single medial bulb bearing two small cirri on dorsal margin; mouth small, terminal; small villiform teeth on jaws forming narrow bands, those on ceratobranchial V forming two large, closely spaced and elongated patches, and quadrangular tooth patches on vomer and palatines.

Scales on body surface in the form of relatively blunt bucklers ( Figs. 4 A, 5A–B), few in number, mostly associated with lateral line, skeleton and body margins; a few small bucklers may be present between principal bucklers on dorsal surface of subopercle; center of disc usually with large naked area ( Fig. 4 C, 5D); 5–6 bucklers on each side of frontal ridge, the first two relatively small situated at anterolateral corner of orbit, the third and fifth or sixth bucklers relatively large in size ( Fig. 5 A); a row of a few small bucklers on the skin dorsal to eye; many small flat bucklers on dorsal surface of skull, two larger on posterior margin of skull, followed by a median row at post-cephalic region; a pair of bucklers at origin of dorsal fin. Ventral surface totally naked excluding a few rounded and flat bucklers without apical spines on pelvic fin base ( Fig. 5 D); buckler of subopercle relatively blunt, with a spine directed forward ( Fig. 5 C), some tiny spinelets may be present on lateral side in small individuals. Caudal peduncle covered with large bucklers, the interspaces densely covered by smaller bucklers, those on dorsal surface forming 2 irregular rows, those on lateral side forming 2 rows of about equal size associated with lateralline, the lower row dense in arrangement, those on ventral surface of caudal peduncle forming two rows between anus and anal fin, 4–5 relatively flattened bucklers on each row; posterior portion of anus surrounded by 4–5 bucklers of larger size than neighouring bucklers.

All fins naked, with small bucklers only on base of caudal fin rays; inter-radial of pectoral fins thin, transparent; dermal cirri present on disc margin, lateral sides of tail and in association with lateral line scales.

Coloration. Preserved specimen: Dorsal surface uniformly creamy-white to brown, all fins similar to background color. Fresh specimen (from colour image of holotype): body pale brownish-grey, with bright yellow vermiculations between whitish bucklers on disc; tip of rostrum dark, patches of dusky pigment on posterior disc; caudal trunk crossed by two faint dusky bands; pectoral fins pale with narrow dusky tips; caudal fin pale with two dusky reddish bands, one basal and one broadly marginal.

Size. A small species with adult body size up to 51.1 mm SL.

Distribution. Known from the type series and a non-type from seamounts and oceanic ridges north of New Zealand and south of New Caledonia, at depths of 420–677 m ( Fig. 3 ).

Etymology. From the Latin “ parva ”—small, in reference to the small adult size of the species; the largest (mature) specimen was 46.4 mm long.

Remarks. Malthopsis parva sp. nov. is most similar to M. jordani in having ventral surface usually naked, but different in having the rostral spine directed upward and forward (vs. nearly upward vertically); a relatively large eye (14.3–17.5% SL vs. 12.5–14.9%); an anterior-directed spine on subopercular buckler usually present. It is also similar to M. annulifera but different in having the rostral spine directed rather upward (vs. nearly forward horizontally); bucklers usually absent from abdomen (vs. usually present), no rings on dorsal surface (present and up to 20 in number), and a relatively small adult body size.

Figures

FIGURE 3. Distribution map of ogcocephalid species found in New Zealand waters. Square = Halieutaea stellata; star = Halieutopsis bathyoreos; triangle = Malthopsis asperata; cross = Malthopsis mitrigera; and circle = Malthopsis parva. One dot may represent more than one capture. Open dots indicate the holotype localities, including the holotype of H. maoria (open square).

FIGURE 4. Malthopsis parva sp. nov., holotype, NMNZ P. 017180, 46.4 mm SL. A. dorsal view. B. lateral view. C. ventral view. D. drawing of dorsal view, illustrated by M. Freebone. E. CSIRO 6031 - 01, paratype, 51.2 mm, fresh, photo by CSIRO. A – C. photo by C. Struthers.

FIGURE 5. Malthopsis parva sp. nov., holotype. A. closed view of dorsal head. B. closed view of lateral head. C. closed view of left subopercular region. D. ventral view of disc showing the naked area and some flattened bucklers at pelvic fin base area. Photo by C. Struthers.