Pezichthys compressus, Last & Gledhill Csiro, 2009

Last, Peter R. & Gledhill Csiro, Daniel C., 2009, A revision of the Australian handfishes (Lophiiformes: Brachionichthyidae), with descriptions of three new genera and nine new species 2252, Zootaxa 2252 (1), pp. 1-77 : 38-40

Pezichthys compressus sp. nov.

Figs 2 , 4 , 14, 16; Tables 3, 7–10

Holotype. CSIRO H 4447–01 , 42.4 mm SL, south of Cape Everard , Victoria, 37° 58'S, 149° 12'E, 112 m, 13 Dec. 1996.

Paratype. NMV 29409–001 , 33.9 mm SL, south-east of Lakes Entrance, Bass Strait , Victoria, 38° 33'S, 148° 24'E, 218 m, 6 Jun. 1984 .

Diagnosis. Member of the genus Pezichthys with a combination of the following characters: esca large, 35–36% of illicium length; illicium slender, without dermal spinules, its length 19–23% SL, 2.4–2.8 times in head length; head length 5.2–5.4 times snout length; snout short 10–11% SL; eye 8.1–8.3 times in head length; maximum width of body 25–32% SL; interorbital broad, width 12–13% SL; scale bases stellate with short, weakly divergent, bifurcate spinules (except for those closely associated with pores of the acousticolateralis system); dorsal-fin rays and membranes with full or partial coverage of spiny scales; first dorsal-fin base length 26–28% SL; second dorsal-fin rays 14–15, fin base 57–62% SL; length of second dorsal-fin spine 1.5 times length of longest ray of second dorsal fin; anal-fin rays 8–9; body and fins uniform pale pink in life.

Description. D1 2 (2, n= 1 paratype); D2 15 (14); A 9 (8); Pc 7 (7); Pv i, 4 (i, 4); C 1 (1) + 6 (5) + 2 (3) = 9 (9); Vt 10 (10) + 11 (11) = 21 (21).

Body short, deep, moderately to strongly compressed; upper anterior profile strongly convex, upright before second dorsal fin; upper margin of eye well below top of head, at level of illicial base; almost oval when viewed anteriorly; nape humped very slightly; anterior ventral profile strongly convex; abdomen expanded; caudal peduncle short, length 3.5 (5.9)% SL. Head length 52 (55)% SL; snout variable in length, 5.4 (5.2) times in head; eye very small, lateral, somewhat embedded, 8.3 (6.9) times in head length; gill opening small, aperture subequal to pupil, located closely adjacent insertion of pectoral fin; nostrils indistinct, overlain with spinules in holotype, enlarged with protruding, tubular anterior opening in paratype; posterior opening almost dorsal to anterior opening, separated slightly from orbit. Mouth small, very narrow, terminal to slightly inferior, weakly protractile; upper jaw strongly oblique, 3.6 (3.4) in head; lips fleshy; angle of jaw deeply recessed into groove, situated below posterior eye; tongue rounded apically. Teeth minute, villiform, in narrow bands in both jaws; vomer apparently edentate (mouth not dissected - roof covered with long papillae obscuring dentition).

Skin thick, uniformly covered with short, bifid, spinulose scales; no separate wart-like patches of skin; no obvious dermal flap present on mid-arm of pectoral-fin; dermal flaps absent from body. Body scales close-set, distributed over entire body and widely over fins; spinules on body not arranged in defined rows, more or less equidistant from each other; scale bases embedded, not within raised mound of thickened skin. Spinules short, well exposed, bifurcating above skin, apical spines diverging slightly (spines of each spinule subequal to or slightly longer than the distance between their tips), not connected distally by integument; erect on upper surface and tail, mainly directed posteroventrally; those on belly not significantly smaller than those above, semi-erect; scale bases stellate, variable in shape, with strongly irregular margins, their width usually greatly exceeding spinule length; scale base extremities usually blunt; spinules arising from near middle of scale base. Entire surfaces of both dorsal fins (including membranes) and upper surface of pectoral fin covered with spinulose scales; similar spinules in rows along fin rays of other fins. Illicium base spinulose, main stem naked; covering of skin thin. Scales of acoustico-lateralis system bicuspid, well demarcated from main spinules; anterior spine apices overlain with broad, flattened, lobe-like integument; scales widely separated and arranged in indistinct rows; most pronounced around mouth.

Illicium terminal on snout, slender, 2.8 (2.4) times in head, 1.3 (1.1) times in length of second dorsal-fin spine; apex of esca just short of base of third dorsal-fin spine when fin depressed; partly retractable into shallow groove on either side of first dorsal fin; esca moderately large, finely filamentous, about 3 times in length of illicium; filaments consolidated in holotype, free filamentous branches in paratype; illicial base not bulbous. First dorsal fin very small, short; spines close together, second spine almost confluent with base of illicium, longer than third spine; fin membrane extremely thick, fleshy, expanded almost to apex of each spine (second spine barely visible); posterior extension of membrane very short, terminating forward or only slightly behind apex of erect, third dorsal-fin spine; anterior elements of both fins very strongly recurved; first dorsal-fin base 2.4 (2.1) times in second dorsal-fin base. Second dorsal fin very low, weakly incised, anterior and penultimate posterior rays longest; rays simple; fin base elongate, 62 (57) % SL; longest ray of second dorsal fin 1.5 (1.5) times in length of second dorsal-fin spine; basal membrane relatively thick, concealing bases of all fin rays, covering almost three-quarters of anterior fin rays and about half of posterior rays. Anal fin short, base fleshy, margin weakly incised; penultimate posterior rays slightly longer than those anteriorly; anal-fin base 2.3 (1.9) times in second dorsal-fin base. Pectoral fin short, very weakly arm-like, elbow extending just beyond gill opening; fin rays digitiform, slender, membranes moderately incised, not increasingly so posteriorly, tips flexible, slightly flattened (often recurved distally). Pelvic fin very short, narrow; rays fine digitiform, slender, moderately incised; anterior spine short, embedded and indistinct; fin located on ventral surface, directed ventrally, base aligned horizontally; interpelvic space narrow, convex. Caudal fin small, narrowly rounded; length 3.3 (2.8) times caudal peduncle depth.

Coloration. In life: Uniformly pale pink (fading to white in preservative), no evidence of spots or other markings in types.

Size. Attains at least 42.4 mm SL (ca. 58 mm TL); single paratype 33.9 mm SL. Size of newly hatched young and egg capsule diameter unknown.

Distribution. Demersal off southeastern Australia, known from two specimens, collected from eastern Bass Strait, south of Cape Everard (37° 58'S, 149° 12'E) at 112 m depth, and south-east of Lakes Entrance (38° 33'S, 148° 24'E), Bass Strait, Victoria at ca. 220 m depth.

Etymology. Derived from the Late Latin compressare (to press hard) in reference to its laterally flattened body shape. Proposed vernacular name: Narrowbody Handfish.

Comparisons. Differs from similarly sized P. amplispinus in having a much deeper (depth at origin of second dorsal fin 47–48 vs. 32–42% SL) and more compressed body shape; a longer first dorsal-fin base (26– 28 vs. 18–20% SL), maxilla (length 15–16 vs. 12–14% SL), esca (length 6.8–8.0 vs. 3.1–4.2% SL), distance from base of third dorsal-fin spine to origin of second dorsal fin (28–30 vs. 23–28% SL) and pre-illicial distance 3.6–5.8 vs. 0.2–1.4% SL; a wider interorbit (width 12–13 vs. 8.1–11% SL); deeper caudal peduncle (11–12 vs. 9.3–11% SL); relatively larger esca (35–36 vs. 19–21% of illicium length); a narrower eye (horizontal diameter 6.4–6.6 vs. 7.0–8.5% SL); shorter caudal peduncle (length 3.5–5.9 vs. 6.8–11% SL); and shorter second (length 24–26 vs. 32–36% SL) and third dorsal-fin spines (length 16–19 vs. 19–26% SL). It also differs in the following ratios: head 8.1–8.3 vs. 6.2–7.7 times eye length; second dorsal fin spine 1.1–1.3 vs. 1.7–2.2 times illicium length; illicium 2.7–2.9 vs. 4.7–5.3 times esca length; length of second dorsal-fin base 2.1–2.4 vs. 2.9–3.4 times first dorsal-fin base; caudal-fin length 2.8–3.3 vs. 3.5–4.6 times caudal peduncle depth. Pezichthys compressus also has a much plainer coloration (almost plain vs. strong pattern of bars and mottling). It belongs to a subgroup of Pezichthys that also contains P. eltanini . These species have a large esca (exceeding a third of illicial length) and scales with stellate bases.

Remarks. Known from only two specimens collected off southeastern Victoria. The geographic and depth ranges for this species overlap with other handfishes in an area that has been subjected to substantial commercial fishing and research surveys ( Smith & Wayte, 2002). The lack of material collected possibly reflects a scarce and patchy distribution, rather than biases due to sampling methods. While nothing is known of the breeding ecology, or the preferred habitat of Pezichthys compressus , it is likely that the prolonged trawl and dredge effort in this area has impacted on the distribution and abundance of this species.

Figures

FIGURE 2. Illustrations of the illicium and esca of: A. Brachionichthys australis, CSIRO H 4114–07, 55.8 mm SL; B. Brachionichthys hirsutus, CSIRO T 7, 78.9 mm SL; C. Brachiopsilus dianthus sp. nov., CSIRO H 4995–01, holotype, 99.5 mm SL; D. Brachiopsilus dossenus sp. nov., NMV A 29405–002, holotype, 65.0 mm SL; E. Brachiopsilus ziebelli sp. nov., CSIRO T 1993–01, holotype, 101.5 mm SL; F. Pezichthys amplispinus sp. nov., CSIRO H 4460–01, 37.2 mm SL; G. Pezichthys compressus sp. nov., CSIRO H 4447–01, holotype, 42.4 mm SL; H. Pezichthys eltanini sp. nov., LACM 11516–1, holotype, 30.0 mm SL; I. Pezichthys macropinnis sp. nov., CSIRO H 5317–02, holotype, 20.5 mm SL; J. Pezichthys nigrocilium sp. nov., CSIRO H 6154–01, holotype, 40.8 mm SL; K. Sympterichthys moultoni sp. nov., CSIRO H 3773–03, holotype, 45.1 mm SL; L. Thymichthys politus, CSIRO H 782–01, 67.3 mm SL; M. Thymichthys verrucosus (tasselled morph), CSIRO T 5, 51.3 mm SL; and N. Thymichthys verrucosus (eastern form) CSIRO H 3781– 01, 63.5 mm SL.

FIGURE 4. Skin morphology of: A. Pezichthys compressus sp. nov., CSIRO H 4447–01, holotype (x50); B. Pezichthys eltanini sp. nov., LACM 11516–1, holotype (x65); C. Pezichthys macropinnis sp. nov., CSIRO H 5317–02, holotype (x40); D. Pezichthys nigrocilium sp. nov., CSIRO H 6154–01, holotype (x40); E. Sympterichthys moultoni sp. nov., CSIRO H 3773–03, holotype (x50); F. Sympterichthys unipennis, MNHN A 4630, holotype (x50). All images orientated as a view of mid-upper body on left side (i.e. anterior part to left).