Syncomistes butleri Vari, 1978

Shelley, James J., Delaval, Aurélien & Le, Matthew C., 2017, A revision of the grunter genus Syncomistes (Teleostei, Terapontidae, Syncomistes) with descriptions of seven new species from the Kimberley region, northwestern Australia, Zootaxa 4367 (1), pp. 1-103 : 32-37

Syncomistes butleri Vari, 1978

( Tables 11 , 12 , S 22 & S 23 ; Figures 10 & 11)

Syncomistes butleri, Vari 1978: 311 ; Paxton et al. 1989: 536 (in part); Larson & Martin 1990: 55; Hutchins & Smith 1991: 22 (in part); Unmack 2001: 1063 (in part); Allen et al. 2002: 236 (in part); Moore et al. 2008: 24 (in part); Larson et al. 2013 (in part): 162; Allen et al. 2017: online (in part).

Corresponds to the nominated taxa code ‘ S. butleri I’ of Shelley (2016).

English vernacular name: Sharpnose grunter.

Holotype (examined): WAM P.25385-001 [physical specimen destroyed (see remarks), photo and description presented in Vari 1978], 124 mm SL, Lilly (Barramundie) Lagoon near Barramundi Creek, a tributary to the South Alligator River, at the point where Barramundie Creek intersects the Oenpelli–Darwin Road , Northern Territory, Australia, (?) 12° 24' 6.39'' S, 132° 59' 44.86'' E. The holotype was obtained with rotenone by W. H. Butler, G. J. Nelson, and D. E. Rosen, May 11, 1969 .

Paratypes (measured): 1 specimen. Paratype specimens (measured and not measured) were collected by the same party and methods. WAM P.25388-001 (1) 165.5 mm SL, South Alligator River Crossing , Oenpelli, Darwin, (?) 12° 25' 35.80'' S, 132° 57' 55.72'' E, May 11, 1969 .

Paratypes (not measured): 70 specimens, 32–175 mm SL. AMNH 35653 (13), 32–160 mm; WAM P-25388- 0 0 1 (11), 55–175 mm, Barramundie Creek next to the type locality, May 12, 1969 ; AMNH 35647 (11), 58–112 mm; WAM P-25386-001 (5), 54–78 mm, South Alligator River on the Pine Creek to Oenpelli Road, (?) 12° 56' 12.93" S, 132° 32' 29.37" E, May 11, 1969 ; AMNH 35652 (2), 108–118 mm, main stream of Mary River on Pine Creek to Oenpelli Road, 13° 36' 9.66" S, 132° 13' 7.69" E, May 10, 1969 ; AMNH 35642 (2), 50–53 mm, Barramundie Creek on Pine Creek to Oenpelli Road, (?) 12° 24' 23.35" S, 132° 59' 33.58" E, May 11, 1969 ; AMNH 35643 (11), 44–54 mm, Barramundie Creek at Oenpelli to Darwin crossing, (?) 12° 24' 6.39'' S, 132° 59' 44.86'' E, May 12, 1969 ; AMNH 35645 (10), 46–59 mm; WAM P-25389-001 (5), 44–57 mm, East Mary River ( Soda Creek ) below Oenpelli to Darwin Road crossing, (?) 12° 54' 26.35" S, 131° 38' 44.84" E, May 13, 1969 .

Non-type Material (measured): 15 specimens, 66.7–237 mm SL. NTM S.17360-003 (2) 68.8–217 mm SL, Bridge Billabong, Mary River, 12° 54' 28.8'' S, 131° 38' 45.6'' E, July 10, 2012, obtained with a backpack electrofisher by Q. Allsop; NTM S.11213-010 (1), 93.1 mm SL, Deaf Adder Creek, South Alligator River, 13° 9' 0'' S, 133° 4' 58.8'' E, June 7, 1973, obtained using gill nets by S. H. Midgley; NTM S.16345-004 (1), 180 mm SL, Long Billabong, South Alligator River, 13° 13' 58.8'' S, 132° 16' 58.8'' E, July 26, 1988, method unknown, obtained by J. Bywater; NTM S.15858-003 (1), 94.9 mm SL, Goyder River, 13° 1' 40.8'' S, 134° 58' 37.2'' E, October 14, 2003, obtained using gill nets by D. Wilson and S. Brooks; NTM S.17064-002 (6), 66.7–119 mm SL, Mann River, 12° 41' 38'' S, 134° 3' 23'' E, November 13, 1977, obtained using a scoop net by ERISS; NTM S.17452-002 (3), 114–237 mm SL, Billabong, Marrakai Road, Adelaide River, 12° 55' 33.6'' S, 131° 16' 1.2'' E, January 4, 2013, obtained using a backpack electrofisher by M. Hammer and D. Wilson.

Diagnosis: A large species of Syncomistes (recorded up to 280 mm SL, commonly 150–200 mm SL). Syncomistes butleri differs from all other species within the Syncomistes complex by a combination of the following characters: lower jaw rounded anteriorly, making a ‘U-shape’ when viewed from below, in juveniles and adults ( Fig. 5a ); mouth slightly oblique; teeth broad and large relative to Syncomistes , flat, asymmetric, margins convex posteriorly and straight to slightly concave anteriorly, widest point closest to mid-point of tooth, apical region tapered to slight point ( Fig. 6b ); body often with 5–6 slightly wavy brown stripes running horizontally along sides; usually ≥ 11 gill rakers on the upper arch and ≥ 30 in total; usually <6.0 teeth per mm of jaw length; distributed between the Adelaide and Goyder rivers of the Northern Territory.

Description: See Table 11 for a summary of meristic variation by type material and other material examined and Table S22 meristic variation across all specimens combined. Dorsal fin spines XII (XI–XII), rays 13 (12–13); anal fin spines III, rays 9; caudal fin rays 10+8+7+10 (9–10+8+7+9–10, n = 3); pectoral fin rays 16 (16–17); pelvic spines I, rays 5; vertebrae 11 + 14 = 25 (n = 3); lateral line scales 51 (49–53); scales above lateral line 11 (9–12); scales below lateral line 19 (17–20); pre-dorsal scales 20 (12–20); cheek scale rows 5 (4–6); caudal peduncle scales 30 (26–31); gill rakers on first arch 11+20 = 31 (8–12+18–21 = 27–32); opercular spines 2 (2–7); preopercular spines 29 (12–50).

See Table 12 for a summary of morphometric variation by type material and other material examined and Table S23 morphometric variation across all specimens combined. Dorsal profile steep: straight, convex, or slightly concave from tip of snout to occiput, slightly concave at occiput, convex or straight from occiput to dorsal fin origin, and convex behind dorsal fin origin to base of last dorsal ray, then horizontal to caudal fin base. Ventral profile slightly convex and downward angled on underside of head, convex from pelvic fin origin to below last dorsal fin ray, and horizontal to caudal fin base. Lateral line continuous from behind head to base of caudal fin, and approximately parallel with dorsal profile. Body depth at dorsal fin origin 38 (34.4–46.1) % SL; body depth at anal fin origin 32.9 (27.5–40.2) % SL; caudal peduncle length 16.5 (14.0–18.2) % SL; caudal peduncle depth 12.8 (11.4–14.4) % SL; pre-anus length 67.1 (63.6–70.1) % SL. Head length 31.5 (28.3–33.5) % SL; head pointed; snout length 39 (37.1–41.5) % HL; upper-jaw length 27.7 (22.7–31.0) % HL; jaws equal throughout development; jaw width 28.6 (25.4–31.7) % HL. Mouth terminal, horizontal or slightly angled upwards in lateral profile. Outer row of large teeth of same size with 3 (2–3) rows of smaller teeth on both jaws, embedded in a jelly-like gum. Teeth in outer row of upper jaw 56 (44–90) number varying with size, 4 (3.1–7.4) / mm when standardised with upper jaw length; teeth on outer row of lower jaw 62 (38–79), number varying with size, 5.6 / mm when standardised with upper jaw length; tooth size decreasing from outer row to inner rows. Teeth laterally compressed, broad and large, asymmetric shape, margins convex posteriorly and straight to slightly concave anteriorly, widest point closest to mid-point of tooth, apical region tapered to slight point, teeth fitted close together with some overlap (Tooth Morphotype 1; Fig. 6b ), laterally pointed in lower jaw, but not extending beyond outer lip. Toothless medial hump present on dorsal surface at symphysis of lower jaw, opposite toothless region of upper jaw in some specimens. Lower jaw U-shaped in juveniles and adults when viewed from below (Morphotype 1; Fig. 5a ). Upper jaw usually with fleshy, narrow, lip fold that is mostly discontinuous across the ventral midline, but occasionally continuous. Orbital diameter 23.3 (17.3–29.2) % HL; inter-orbital width 32.6 (28.9–35.9) % HL; post-orbital length 40.3 (36.6–44.8) % HL. Inter-orbital smooth, with bony ridge above each orbit. Parietal and supracleithrum sometimes serrated. Lower opercular spine longer and more robust than upper opercular spine, sometimes extend beyond edge of opercular membrane; preopercular spines serrate, longest and most robust on apex of preopercle, reduced in size dorsally and anteriorly, anteriormost spine situated behind posterior edge of orbit. Intestinal pattern of adults highly convoluted; large amount of looping to left of stomach; juveniles with less convoluted pattern.

Dorsal fin origin posterior to vertical plane through pectoral fin origin, anterior to pelvic fin origin, terminates at base of last dorsal ray. Dorsal fin sheath scales 3 (2–3); 5th (5th–7th) dorsal spine longest, length 17.6 (12.8–18.2) % SL; spines progressively shorter from first and last respectively; last dorsal fin spine fully linked to first dorsal fin ray by membrane; 5th (1st–5th) dorsal fin ray longest, length 15.1 (13.3–17.3) % SL; margin of rayed portion rounded to tip of last ray; dorsal fin base length 56.4 (52.8–60.0) % SL; dorsal fin length 63.0 (58.7–67.6) % SL; pre-dorsal fin length 41.2 (38.4–43.2) % SL. Anal fin origin immediately posterior to vertical plane through base of last dorsal fin spine, terminates at base of last ray. Anal fin sheath scales 3 (2–5); 2nd (2nd–3rd) anal fin spine longest, length 17.6 (13.3–20.9) % SL; 1 st anal fin ray longest, length 17.1 (14.8–18.7) % SL; subsequent rays progressively shorter; distal margin of rayed portion rounded; anal fin base length 17.7 (15.9–19.9) % SL; anal fin length 24.8 (22.3–27.8) % SL; pre-anal fin length 71.6 (67.9–75.0) % SL. Caudal fin slightly emarginate in juveniles, emarginate in adults; upper caudal lobe 28.5 (24.3–33.2) % SL; middle caudal ray 19.2 (17.5–21.2) % SL. Pectoral fin length 20.8 (17.4–22.4) % SL; pre-pectoral fin length 30.6 (27.7–33.0) % SL. Pelvic spine 22.1 (20.1–24.4) % SL; 1 st pelvic ray longest (1st–2nd), 22.1 (20.1–24.4) % SL; pelvic fin length 24.1 (20.7–26.2) % SL; pre-pelvic fin length 40.8 (39.0–43.4) % SL.

Colour when fresh: Juveniles <65 mm SL often with 5–6 longitudinal body stripes: first running along sheath at base of spinous dorsal from third dorsal spine to third or fourth ray; second, from origin of dorsal to below soft dorsal; third, from above eye across post-temporal to beyond soft dorsal; fourth stripe widest, about twice width of others, from back of eye across opercle to caudal base; fifth, from pectoral base to rear of soft anal; sixth indistinct and sometimes lacking below fifth stripe to spinous anal. Top of head pale except for some pigmentation along posterodorsal edge of skull. Iridescent horizontal stripe running from rear of maxillary under eye to opercle. Opercle and subopercle with dark blotch extending ventrally from opercular spine. Dorsal fin with dusky membranes between spines and spots of pigmentation at base of ray membranes. Caudal with dark vertical bar at base; bar broken into two or three spots in some specimens. Membranes of spinous anal dusky. Soft anal with dark basal blotch. Membranes of pelvics dark. Pectorals colourless.

Adult specimens usually lacking longitudinal body stripes or caudal bar. Overall colouration uniformly dark grey, with edge of each scale more heavily pigmented; pigmentation increases dorsally. Top of head to level of snout, top of lower lip, and suborbital region dark. Opercle and subopercle dark below opercular spines. Spinous and soft dorsals dark, with paler edges, especially soft dorsal. Caudal, anal, and pelvic fin dark; first two with pale margins in some individuals. Pectorals colourless.

Colour when preserved: Juveniles and adults uniformly dark brown to grey with hints of pale colouration becoming more dominant towards the ventral region. All fins slight to dark brown. Mostly pale brown when viewed ventrally. Lateral line is distinctly pale in colouration. Overall colouration fades from darker to lighter the longer the specimen is preserved.

Distribution: See Fig. 11 . Occurs throughout rivers in the Northern Territory from the Adelaide to the Goyder River.

Ecology: Prefers deeper sections of slow-flowing creeks and rivers, as well as billabongs. Found in clear and turbid waters, over muddy to rocky substrates, often where algae is abundant. Adults form shoals around snags.

Juveniles predominantly reside in riffle habitat. Individuals sexually mature at 120–140 mm and breed during the wet season. Eggs are large (~ 3mm) and non-adhesive. Diet primarily consists of filamentous algae along with some detritus and invertebrates.

Comparison: Syncomistes butleri , along with S. bonapartensis , is very different from other Syncomistes . Distinctive features include a terminal mouth, a wide, rounded U-shaped jaw when viewed from below, and a thick, fleshy lip fold on the upper and lower lip, a deeper body at the dorsal fin origin 38 (34.4–46.1) % SL and at the anal fin origin 32.9 (27.5–40.2) % SL, and a distinctively steep ventral profile that is straight or concave in adults and slightly convex in juveniles.

The species is very similar in appearance to S. bonapartensis , but on average it has more gill rakers on the upper arch 11 (8–12) versus 9 (7–10) and overall 31 (27–32) versus 27 (26–30), has fewer teeth in relation to jaw length 4.0 (3.1–7.4) versus 6.0 (3.8–7.3), longer head length 31.5 (28.3–33.5) % SL versus 29.6 (23.8–33.5) % SL, and a larger orbital diameter 23.3 (17.3–29.2) % HL versus 21.4 (16.6–28.7) % HL. This species also has 1–2 fewer horizontal body stripes when they are present. This character is particularly useful in distinguishing juvenile specimens, as stripes are most often present.

Etymology: The specific name butleri honors Dr. William Henry “Harry” Butler, a popular naturalist and member of the American Museum of Natural History–Australian Expedition of 1969.

Remarks: The type series of Syncomistes butleri was found to include specimens from the Daly, Victoria, Ord, and Drysdale rivers now referable to S. bonapartensis (see Remarks above, under Sycomistes bonapartensis ). This is one of three species within Syncomistes whose range does not overlap with a congeneric.

The holotype, and those of S. trigonicus and S. kimberleyensis , were allowed to dry out while on loan, and had deteriorated to such an extent that they were considered ‘totally useless (Glen Moore, pers. comm. 2017) and were discarded by Barry Hutchins in 1990 ( Hutchins & Smith 1991). We consider that the photograph and meristic and morphometric measurements presented in Vari (1978) still adequately represent the holotype.

Figures

FIGURE 5.

FIGURE 6.

FIGURE 10.

FIGURE 11.

Tables

TABLE 11. Summary of meristic variation in Syncomistes butleri (values for number of teeth of upper and lower jaw are per mm of jaw length). Holotype counts were taken from the photograph in Vari (1978). Dashes indicate measurements that could not be made from the image.

	Holotype	Paratype (N = 1)			Non-type Material (N = 15)
Character					Mode	Mean		Min.	Max.	S.D.
DS	12	12			12	11.9		11.0	12.0	0.26
DR	13	12			13	12.9		12.0	13.0	0.35
AS	3	3			3	3.0		3.0	3.0	0.00
AR	9	9			9	9.0		9.00	9.00	0.00
PecR	-	16			16	16.1		16.0	17.0	0.26
PelS	-	1			1	1.0		1.0	1.0	0.00
PelR	-	5			5	5.0		5.0	5.0	0.00
UUCR	-	10			10	9.5		9.0	10.0	0.71
UBCR	-	8			8	8.0		8.0	8.0	0.0
LBCR	-	7			7	7.0		7.0	7.0	0.0
LUCR	-	10			10	10.0		10.0	10.0	0.0
LLSc	51	49			51	50.7		49.0	53.0	0.90
LD	9	9			11	10.6		9.0	12.0	0.74
LA	16	19			19	18.6		17.0	20.0	1.12
PDSc	-	16			18	18.1		12.0	20.0	2.20
DSSc	-	2			3	2.7		2.0	3.0	0.49
ASSc	-	3			3	3.3		2.0	5.0	0.72
CScR	-	4			4	4.5		4.0	6.0	0.64
CPSc	-	28			30	29.5		26.0	31.0	1.25
GRup	-	9			11	10.6		8.0	12.0	0.91
GRlow	-	20			20	19.7		18.0	21.0	0.90
GRtot	-	29			31	30.3		27.0	32.0	1.44
PcV	-	11			11	11		11	11	0.00
CV	-	14			14	14		14	14	0.00
TV	-	25			25	25		25	25	0.00
LDR	3	3			3	3.0		1.0	5.0	1.20
LDS	7	6			6	5.9		5.0	7.0	0.59
LAR	1	1			1	1.0		1.0	1.0	0.00
LAS	2	2			2	2.1		2.0	3.0	0.26
LPR	1	1			1	1.1		1.0	2.0	0.26
Tup	-	4.5			6	6.0		4.3	7.2	0.98
Tlow	-	4.3			6	5.6		3.8	7.3	1.10
TRup	-	2			4	3.6		3.0	4.0	0.51
TRlow	-	1			4	3.5		3.0	4.0	0.52
OS	2	2			2	2.9		2.0	7.0	1.77
PS	-	27			22	23.3		12.0	50.0	8.97

TABLE 12. Morphometric variation in Syncomistes butleri (values are percentages of denominators in ratios, except for SL). Holotype proportions were taken from the photograph in Vari (1978). Dashes indicate measurements that could not be made from the image.

	Holotype	Paratype (N = 1)			Non-type Material (N = 15)
Character					Mean	Min.		Max.	S.D.
SL (mm)	124.0	165.5			127.4	66.7		237.0
BDd / SL	40.3	38.5			38.0	34.4		46.1	3.65
BDa / SL	40.0	33.2			32.9	27.5		40.2	3.47
CPL / SL	12.7	15.1			16.5	14.0		18.2	1.29
CPD / SL	14.2	12.4			12.8	11.4		14.4	0.87
HL / SL	29.9	29.5			31.5	28.3		33.5	1.40
OD / HL	25.0	19.0			23.3	17.3		29.2	3.03
IoW / HL	-	36.6			32.6	28.9		35.9	2.28
PoL / HL	41.5	34.6			40.3	36.6		44.8	2.54
SnL/ HL	37.9	39.1			38.9	37.1		41.4	1.27
JLup / HL	27.7	26.6			27.7	22.7		31.0	2.21
JW / HL	-	29.0			28.6	25.4		31.7	1.92
PDFL / SL	40.5	39.9			41.2	38.4		43.2	1.46
PPecL / SL	28.5	29.9			30.6	27.7		33.0	1.49
PPelL / SL	39.3	40.5			40.7	39.0		43.4	1.09
PAL / SL	68.8	66.8			67.1	63.6		70.1	2.08
PAfL / SL	73.0	72.8			71.6	67.9		75.0	2.21
DFBL / SL	58.6	58.1			56.4	52.8		60.0	2.18
DFL / SL	64.1	61.2			63.1	58.7		67.6	2.80
DFRL / SL	14.0	14.7			15.5	13.3		17.3	1.14
DFSL / SL	16.4	20.1			16.0	12.8		18.2	1.54
AFBL / SL	20.5	17.1			17.6	15.9		19.9	1.02
AFL / SL	24.6	24.1			24.8	22.3		27.8	1.52
AFSL / SL	19.7	13.1			17.6	13.3		20.9	1.99
AFRL / SL	15.1	15.1			17.1	14.8		18.6	1.21
PecL / SL	17.6	21.1			20.8	17.4		22.4	1.34
PelL / SL	25.5	22.5			24.1	20.7		26.2	1.59
PelSL / SL	15.2	14.1			13.8	11.1		16.0	1.29
PelRL / SL	-	23.5			22.0	20.1		24.4	1.31
CLLup / SL	28.7	33.4			28.5	24.3		33.2	2.54
CLLmid / SL	19.8	21.1			19.2	17.5		21.2	1.11