Toxotes kimberleyensis, Allen, 2004

Allen, Gerald R., 2004, Toxotes kimberleyensis, a New Species of Archerfish (Pisces: Toxotidae) from Fresh Waters of Western Australia, Records of the Australian Museum 56 (2), pp. 225-230 : 226-229

Toxotes kimberleyensis n.sp.

Figs. 1 , 2 ; Tables 1–3

Type material. HOLOTYPE: WAM P.25039-002, 126.3. mm SL, Plain Creek Gorge, Beverley Springs Station , West Kimberley District , Western Australia (16°35'S 125°30'E), hook and line near surface, G. Allen and W. Bailey, 1 September 1974 . PARATYPES: AMS I.42570-001, 107.5 mm SL, collected with holotype; NTM S.15530-001, 102.4 mm SL; WAM P.25039-001, 3 specimens, 98.2–109.2 mm SL, collected with holotype; WAM P.25437-001, 65.5 mm SL, May River , Western Australia (17°21'S 124°00'E), rotenone, B. Hutchins and A. Chapman, 26 July 1975 ; WAM P.25440- 006, 15 specimens, 52.5–92.8 mm SL, Lennard River , Western Australia (17°20'S 124°40'E), rotenone, B. Hutchins and A. Chapman, 27 July 1975 .

Diagnosis. A species of Toxotes with the following combination of characters: dorsal rays V, 11–13 (usually 11–12); longest (fourth and fifth) dorsal-fin spines about equal in length and shorter than longest soft dorsal ray in adults; anal rays III,14–16 (usually 15); pectoral rays 12– 13; tubed lateral-line scales 28–33 (usually 30–31); diagnostic colour markings consisting of 4–5 wedge-shaped black bars or saddles without intervening small spots.

Description. Dorsal rays V,12 (11–13), anal rays III,15 (14– 16); pectoral rays 12 (12–13); principal caudal rays 17; gillrakers on lower limb of first branchial arch 7 (6 or 7), usually a single raker on upper limb; tubed lateral-line scales 31 (28– 33); horizontal scale rows above lateral-line to dorsal fin origin 3; horizontal scale rows below lateral line to anal fin origin 9 (8–10); circumpeduncular sc ale rows 16 (17–16).

Body depth 2.2 (2.1–2.3) in standard length; maximum body width 2.4 (2.2–2.6) in depth; head length contained

3.0 (2.6–2.9) in standard length; snout 4.0 (3.5–4.3), eye 3.5 (3.3–3.9), interorbital width 3.0 (2.9–3.3), upper jaw length 1.9 (2.0–2.3); least depth of caudal peduncle 2.5 (2.5– 3.1), length of caudal peduncle 3.0 (2.7–3.7), all in head length.

Mouth large, the lower jaw protruding; mouth opening oblique, angle of jaw about 42 degrees from horizontal axis of body; maxilla slender and scaly, without supplemental bone, reaching a vertical level with middle of eye; fine villiform teeth on jaws, vomer, and palatines; pair of prominent nasal opening on each side of snout just anterior to eye; anterior nostrils in short fleshy tube; scattered sensory pores evident on interorbital region, tip of snout, margin of preopercle, sub-preorbital series, and ventral surface of lower jaw; free edges of preopercle and opercular series smooth except lower margin of preopercle very finely crenate.

Scales of head and body very finely ctenoid, but smooth to touch; head fully scaled except for small naked patch on central rear margin of preopercle; dorsal and anal fins with well-developed basal scaly sheath and small scales extend nearly to margin of fins; outer base of pectoral fin scaled, but axil naked; pelvic axillary scale about half length of pelvic fin; innermost pelvic-fin ray attached to abdomen by membrane.

Lateral line nearly complete (except usually interrupted

by 1–2 tubeless scales above pectoral fin), consisting of simple unbranched tubes, extending from upper rear corner of operculum to hypural base, usually with a pronounced dorsal inflection above pectoral region.

Origin of dorsal fin about level with origin of anal fin, on rear half of body; first dorsal spine 4.8 (4.4–5.0) in head length; spines of dorsal fin gradually increasing in length and thickness to fourth spine, fourth and fifth dorsal spines about equal in length; fifth dorsal spine 1.9 (1.6–2.1) in head length; longest (first two) soft dorsal rays about equal or slightly shorter than tallest dorsal spines, 1.7 (1.5–2.1) in head length; anal spines progressively increasing in length; first anal spine 4.8 (4.7–5.4), and third anal spine 1.9 (1.9–2.4), both in head length; length of dorsal-fin base 0.9 (1.0–1.1), of anal-fin base 1.0 (1.1–1.2), both in head length; caudal fin truncate to very slightly emarginate, its length 1.2 (1.2–1.4) in head length; pectoral reaching a vertical through origin of dorsal and anal fins, the longest ray 1.2 (1.1–1.3) in head length; pelvic fins short, longest ray falling well short of anal fin origin when depressed, 2.2 (2.0–2.5) in head length.

Preserved coloration (in alcohol). Ground colour yellowish white with slight silvery sheen, grading to brown on dorsal

surface; a series of five diffuse blackish bars, primarily on upper side, the last (on caudal peduncle) very faint; dorsal and anal fins dusky blackish, with pale central band; caudalfin membranes dusky blackish; pelvic fins pale tan; pectoral fins translucent with uppermost rays dusky blackish. The paratypes are similar except the dark bars are more vivid and strongly contrasted. In addition, the last bar (on caudal peduncle) is frequently reduced to a small rounded spot, especially in the smallest specimens.

Live coloration (from 35 mm transparency): overall silvery white with five black bars or vertically ovoid spots between eye and caudal fin base; fins generally transparent to whitish in young to dusky blackish (especially dorsal and anal) in adults.

Etymology. The species is named kimberleyensis with reference to the type locality. Major surveys of northern Australian freshwater fishes by the author and co-workers over the past 3 decades indicate that it is restricted to the Kimberley region.

Remarks. Bleeker (1876) described Toxotes oligolepis from a single specimen, 111.7 mm SL. The precise collection locality is uncertain, but according to Bleeker and Weber & de Beaufort (1936), was probably the island of Buru in the Molucca Islands, Indonesia. Specimens from the Kimberley district of Western Australia were previously identified ( Allen, 1978) as T. oligolepis based largely on colour pattern similarity. However, I recently had an opportunity to re-examine Bleeker’s holotype at RMNH and compare it with specimens from Western Australia. Several significant differences were noted.The dorsal spines of T. oligolepis are notably taller and stronger than those of Australian fish. The third dorsal spine is the tallest and strongest, and is significantly higher than the soft portion of the dorsal fin. In contrast the fourth and fifth spines are the tallest and strongest in the Australian fish and are about equal in height or lower than the soft part of the dorsal fin. In addition, theAustralian specimens have a higher lateral-line scale count (30–31) in comparison to T. oligolepis . Although the holotype of T. oligolepis has damaged and missing scales, close inspection of scale pockets reveals a count of about 25. This count is further corroborated by the illustration of T. oligolepis in Bleeker’s Atlas Ichthyologique (1875–1878, pl. 363, Fig.

1), which is reproduced here as Fig. 3 .

Toxotes kimberleyensis is known only from a relatively small area of the western Kimberley district of Western Australia, including the Fitzroy, Meda, May, and Isdell Rivers ( Allen et al., 2002). It is especially common in the Fitzroy system, but appears relatively scarce elsewhere. Unlike T. chatareus and T. jaculatrix that are found in coastal areas of the Kimberley, frequently in brackish water (or marine conditions in the case of T. jaculatrix ), T. kimberleyensis is strictly confined to freshwater. It penetrates well inland, at least as far as Geike Gorge National Park in the Fitzroy system, or approximately 300 km upstream from the sea. The species has an affinity for deeper pools where it swims near the surface, patrolling the shoreline for insects.

The following key provides characters for differentiating the seven known species of Toxotes (modified from Allen, 1978).

Figures

Fig. 1. Toxotes kimberleyensis, holotype, 126.3 mm SL, Plain Creek, Western Australia.

Fig. 2. Toxotes kimberleyensis, about 150 mm total length (G. Schmida photo).

Fig. 3. Toxotes oligolepis, 102 mm SL, L. Speigler drawing from Bleeker (1875–1878).