Heteroclinus longicauda, Hoese & Hay & Dibattista, 2024

Hoese, Douglass F., Hay, Amanda & Dibattista, Joseph D., 2024, A review of the Heteroclinus heptaeolus complex (Pisces: Blennioidei: Clinidae), with three new species and discussion of use of proportions in taxonomic studies, Zootaxa 5432 (3), pp. 301-348 : 320-324

Heteroclinus longicauda n. sp.

Plate 4 , Figures 2 , 8 , 9 , Tables 1–5 , 8 , 11–12

Common Name: Longtail Weedfish

Petraites heptaeolus .— McCulloch, 1908 41, pl. 8, fig 1 (in part, AMS I.8015, Long Bay).

Heteroclinus sp. 3 :— Rennis, Hoese & Gomon 1994: 748 (Sydney, New South Wales to Queenscliff, Victoria and Tasmania); Hoese, Gomon & Rennis 2008: 703 (New South Wales, Victoria and Tasmania).

Heteroclinus sp. 3 .— Kuiter 1993: 331 (habitat).

Heteroclinus sp. 2 . — Kuiter & Kuiter 2018: 288

Holotype. AMS I.16501-006, 1(73), Salt Lake, Nadgee Nature Reserve , New South Wales, 37°23’49”S, 149°57’18”E, F.H. Talbot, D. McMichael and D. Griffin, 25 April 1967.

Paratypes. New South Wales: AMS I.8015, 1(87), Long Bay, Sydney , 33°58’S, 151°15’E, New South Wales, A. R. McCulloch; AMS I.15912-044, 1(94), Cabbage Tree Point, Jervis Bay , 35°00’S, 150°45’E, Macquarie University class, 17 October 1970 ; AMS I.19893-035, 8(60–118), north end of Black Head , Nadgee Nature Reserve , 37°26’26”S, 149°58’22”E, 0–5 m, J. Paxton and party, 26 August 1976 ; AMS I.24274-001, 2(64–70), North Bondi , Sydney, 33°53’S, 151°17’E, New South Wales, R. Reid, 16 April 1979 ; AMS I.28727-020, 5(79–133), Bittangabee Bay, Green Cape, 37°15’08”S, 150°00’30”S, AMS Party, 5 April 1989 ; AMS I.44625-048, 3(58–78), 1 km south of Tathra boat ramp, 33°44’54”S, 149°58’59”E, A. Hay, 7 April 2008 ; AMS I.44633-010, 3(68–141), Moon Bay, 36°41’44”S, 149°59’23”E, A. Hay, 10 April 2008 ; AMS I.45630-001, 1(73), Bendalong, N of boat ramp, 35°14’40”S, 150 32’10”E, 14 March 2011, 0–1 m, AMS Party ; AMS I.45633-075, 1(70), Washerwomans Beach, Bendalong, 35°14’39”S, 150°32’09”E, M. McGrouther, 16 March 2011 ; NMV A.3260, 2(67–71), north end of Black Head, Nadgee Nature Reserve , 0–5 m, New South Wales, 37°26’26”S, 149°58’22”E, J. Paxton and Party, 26 August 1976 ; SAM F7696 (formerly AMS I.19893-035), 2(76–80), north end of Black Head, Nadgee Nature Reserve , New South Wales, 37°26’26”S, 149°58’22”E, J. Paxton and Party, 26 August 1976 . Victoria: NMV A.16228, 1(52), Queenscliff , 38°16’S, 144°40’E, March 1888 . Tasmania: AMS I.20078-003, 1(26), Grassy Port , King Is., 39°55’S, 144°00’E, B.C. Russell , 5 December 1977; WAM P.27559-024, 3(39–50), St. Helens Point, 41°16’S, 148°22’E, B. Hutchins, 25 February 1982 ; WAM P.27572-006, 2(39–86), West Point, Marrawah , 0.1–1.2 m, 40°55’S, 144°42’E, Tasmania, B. Hutchins, 13 March 1982 .

Non-type material. AMS I.19893-035, 1(60), north end of Black Head, Nadgee Nature Reserve , New South Wales, J. Paxton and Party, 26 August 1976 ; NMV A.11356. southern Port Phillip Bay , Victoria

Diagnosis. Dorsal fins III,XXIV–XXVI, 3; anal II, l7–19 (rarely 17); pectoral rays 12–13 (rarely 12); gill rakers on outer face of first arch 2–3 + 7–9 = 8–11, rarely 11; circumorbital head pores uniserial (13–18 pores); no orbital tentacle; nasal tentacle bilobed or rarely trilobed, flap as long as tubular base; middle gill rakers and often uppermost rakers on outer face of first arch branched dorsally; first dorsal fin low (second dorsal spine 6.9–12.4% SL, not showing significant change with size) originating over or slightly behind posterior preopercular margin; third spine originating over or just behind pelvic fin base; last dorsal ray connected by membrane to caudal peduncle about half way from base of last ray to base of caudal fin; body slender with proportion increasing with size (depth at anal origin 17.5.2–22.5% SL in specimens 25.8–50 mm SL, 21.9–27.1% SL in specimens 51–83 mm SL and 23.7–27.9 % SL in specimens 84–141 mm SL). Snout dark, often with stripe from eye to middle of upper lip; dark stripe from dorsoposterior margin of eye continuing onto body below anterior half of dorsal fins; second horizontal dark stripe from posterior margin of eye arching upward to above pectoral fin, connecting with second dark stripe on body often broken into a series of disconnected large dark brown spots; sometimes with white of silver stripe behind eye below dark stripe and sometimes with a dark bar below eye; body sometimes with thin dark stripe above anal fin; clear windows usually only present between last dorsal and last two anal rays and sometimes between some posterior anal rays.

Description. Based on 42 specimens, 26–141 mm SL, 15 male, 14 females, 12 not sexed or immature. First dorsal III* (27); dorsal rays 3*(27); pelvic rays I,3* (27); caudal rays 10*(20), 11(1), 12*(6); vertebrae 14+27(1), 14+28(12); lower gill rakers on outer face of first arch 7(13), 8*(10), 9(1); circumorbital head pores uniserial (13–18; pored lateral line scales l8–24 (arched portion of line) + 25–31 (straight portion of line), anterior lateral line scales18(1), 19(1), 20(3), 21(6), 22*(10), 23(3), 24(1); posterior lateral line scales 25(1), 26(2), 27(3), 28(1), 29*(5), 30(7), 31*(6); total lateral line scales 47(1), 48(3), 49(2), 50(6), 51(6). 52(3), 53*(4), and one 26 mm SL specimen with 17 scales on arched portion and none on straight portion; branchiostegal rays 6*(7); other counts are shown in Tables 1–5 . Vomer with conical teeth arranged in an inverted V, 1 distinct row, with one or two teeth in second row in specimens less than 45 mm SL and 2–3 rows in larger specimens; palatine without teeth.

Head and body laterally compressed, head moderate, length as proportion decreasing with increasing size (23.6– 27.8% SL in adults, 28–30.8% SL in juveniles less than 40 mm SL); snout gently convex in side view, snout slightly shorter than to equal to eye diameter (0.6–1.0 of eye length), snout length not changing significantly with increasing size (4.2–6.6% SL), eye moderate, relative size decreasing with growth (8.0–9.3% SL in specimens less than 40 mm SL, 6.1–8.2% SL in specimens 49–64 mm SL, 5–7% SL in specimens 68–87 mm SL, 5.7–4.4% SL in specimens 89–142 mm SL); interorbital moderate, about two-thirds eye diameter; mouth small, jaws reaching to below middle of pupil to just behind pupil, upper jaw length not showing significant change with size (8.4–10.6% SL); anterior nostril at end of short tube, above upper lip, with short bilobed or rarely trilobed nasal tentacle; posterior nostril with elevated rim above anterior margin of eye; gill rakers on outer face of first arch, pointed and slender, slightly less than half filament length, upper rakers and anterior most rakers typically with multiple branches; rakers on second and following arches pointed, subequal to first row, except for innermost arch, rakers shorter; tongue tip broadly pointed; upper jaw with outer row of blunt, incisiform teeth (slightly compressed), broad below tip, but usually without lateral cusps, enlarged extending to 3–6 inner rows of smaller conical teeth tapering laterally to two rows; lower jaw with outer row of blunt teeth, with small lateral cusps 2–4 inner rows of smaller teeth tapering laterally to a single row laterally.

Genital valve a continuous single lobe with smooth margin and slight notch at posterior end, fully covering genital opening in females and young males. Intromittent organ pointed, without lateral lobes.

Head pores as shown in Figure 8 ; circumorbital and preopercular pores uniserial.

Head largely naked, body scales small and cycloid extending forward to above operculum below anterior end of dorsal fin; scales cycloid overlapping and forming distinct rows, becoming nonimbricate on caudal peduncle; pectoral fin base covered with small embedded scales, scales extending onto base of fin to a maximum of basal one-tenth of rays; scales covering bases of second dorsal spines and membranes between spines, extending to a maximum of basal one half of fin, sparse or absent on membrane windows, not extending onto base of dorsal rays; scales not extending onto anal fin; scales not extending onto base of caudal rays; scales on fins highly variable and possibly easily lost; lateral line scales extending to caudal peduncle in adults, anterior scales overlapping with a single median posterior pore, posterior scales separate with a median pore at each end.

All fin-rays unbranched; first dorsal fin origin, above or just before posterior margin of preoperculum; fin low and slightly longer than anterior spines of second dorsal fin; second spine usually longest, with first and third spines subequal in height; membrane from first dorsal fin connects to base of spine of second dorsal fin; second dorsal origin above upper pectoral insertion and well behind pelvic insertion; first spine of second dorsal slightly shorter than following spine, spines becoming progressively longer posteriorly, with last spine the longest; last two dorsal rays shorter and widely separated from anterior ray; anal origin below 8 th to 10 th spine of second dorsal fin, anal spines distinctly shorter than rays; posterior rays longer, last two rays closely spaced, shorter and widely separate from anterior rays; basal half of last anal ray attached to caudal peduncle by membrane, less than half way to caudal fin base; pectoral fin with rounded posterior margin, central rays longest, reaching to above a point between anus and first anal ray; pelvic rays short and stout, with hidden spine and 3 rays, inner ray about 2/3 length of second ray; caudal fin with truncate to slightly rounded posterior margin, caudal fin length proportion decreasing significantly with increasing size (18.0–21.5% SL in specimens less than 70 mm SL, 18.3–20% SL in specimens 70–94 mm SL 15.5–18.2 in adults over 100 mm SL); caudal fin with 10 thickened rays and an upper and a lower smaller ray, segmented in 26% of specimens examined, 3–5 upper and lower very short procurrent simple rays difficult to discern.

Coloration of freshly collected material ( Plate 4 ). Head and body yellow to brown; dark stripe from near anterior end of lower jaw extending upward and backward through eye narrowing to a thin stripe along base of first and second dorsal fins; horizontal white or silver stripe sometimes present extending posteriorly from upper posterior margin of eye and a similar short stripe from near lower margin of eye; dark stripe extending from posterior middle of eye arching upward extending along back below upper stripe, sometimes broken into large elongate dark brown spots, a faint dark brown broad stripe along midside of body, in some individuals broken into elongate oval spots and a thinner dark brown stripe from behind abdomen running above anal fin, fading posteriorly.

Live coloration. See Kuiter & Kuiter (2018). Similar to coloration of fresh material. Overall head and body colour greenish to light brown, dark brown marking on side variable, often faint ventrally.

Coloration in alcohol. Head and body uniformly light brown, without distinct marking; clear windows between spines often absent, except for prominent window between first and second dorsal rays, in some specimens with a few narrow windows, with transparent areas not fully covering membranes between spines or with membranes lighter than pigment on spines, creating semi-transparent windows.

Distribution. The species is known from Sydney, New South Wales to Queenscliff, Victoria and from northern Tasmania. It is associated with sand, rock and algae to a depth of 8 m; reported from tall kelp and dense Zostera beds ( Kuiter 1993).

Etymology. From the Latin longus (long) + cauda (tail), referring to the elongate caudal peduncle, is a noun in apposition.

Remarks. This species is readily distinguished from all other Australian clinids by the absence of an orbital tentacle and the elongate caudal peduncle, with the base of the caudal fin well behind the point where the membrane from the second dorsal fin attaches to the caudal peduncle. The attachment of the dorsal and anal membranes to the caudal peduncle is similar to that found in Cristiceps , which has a thin elongate orbital tentacle. In the wide separation of the last 2 dorsal rays, the species is similar to other species in the H. heptaeolus complex. It also differs from other species in the heptaeolus complex in having the dorsal fin origin farther back on the head, closer to the posterior preopercular margin than the eye (versus closer to the eye in other species in the complex, see Figure 2 ). In H. longicauda and H. heptaeolus the first dorsal spine is above the point where the skull curves ventrally to the first vertebra, while in the other three species the first spine is well before the inflection point ( Figure 2 ) and the first spine articulates with an elevated crest on the skull.

Regression analyses ( Table 8 ) indicated a y-intercept, significantly different from 0 for head length (p = 0.017), predorsal length (p <0.014), head width (p = 0.018), body depth at anal origin (p <0.001), eye length (p <0.001) and caudal fin length (p = 0.006). Rank correlation indicated all characters decreased with size, except for body depth at anal origin which increased. All of these characters also tested significant, with Kendall’s Tau and where the regression analyses showed a y-intercept not significantly different from 0, also showed no significant values for the rank correlation of the proportions tested with Kendall’s Tau.

Figures

FIGURE 2. Radiograph of skulls of species of the Heteroclinus heptaeolus complex, showing modification and position of pterygiophores and first 3 dorsal spines on skulls of various species.

PLATE 4. Freshly collected specimens of Heteroclinus longicauda: A) male, photo by R. Kuiter, specimen not kept; B) AMS I.45630-001, 73 mm SL. female, Bendalong, New South Wales, photo by M. McGrouther; C) AMS I.44633-010, 92 mm SL female, Moon Bay, New South Wales, photo by M. McGrouther; D) AMS I.44633-010, 70 mm SL male, Moon Bay, New South Wales, photo by M. McGrouther.

FIGURE 8. Head of Heteroclinus longicauda, showing canals (dashed lines) and pores (open circles) and position of dorsal fins; anterior and posterior nostril at end of short tubes elevated above skin, based largely on holotype.

FIGURE 9. Map showing distribution of Heteroclinus longicauda based on material examined.