Syncomistes wunambal, Shelley & Delaval & Le, 2017

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 : 79-84

Syncomistes wunambal , new species

( Tables 29 , 30 , S 22 & S 23 ; Figures 28 & 29 )

Syncomistes trigonicus non Vari 1978: 316: Paxton et al. 1989: 536 (in part); Allen & Leggett 1990: 539 (in part); Hutchins & Smith 1991: 23 (in part); Hutchins 2001: 31 (in part); Unmack 2001: 1063 (in part); Allen et al. 2002: 239 (in part); Moore et al. 2008: 24 (in part); Morgan et al. 2011a: 17 (in part); Allen et al. 2017: online (in part).

Corresponds to the nominated taxa code ‘ S. trigonicus II’ of Shelley (2016).

English vernacular name: Wunambal Grunter.

Holotype (measured): WAM P.34536.001 (104 mm SL), Mitchell Falls, Mitchell River , 14° 49' 10.06'' S, 125° 41' 29.13'' E. The holotype was obtained with backpack electrofisher by J. J. Shelley and M. C. Le Feuvre, June 27, 2013.

Paratypes (measured): nine specimens, 62.5–101 mm SL. All paratypes were obtained in accordance with the holotype. WAM P.34536.002 (3), 74.2–83.7 mm SL, NTM S.18109-001 (1), 77.4 mm SL, NMV A.31449-001 (1), 77.4 mm SL, NMV A.31449-002 (1), 101 mm SL, NMV A.31449-003 (1), 62.5 mm SL, NMV A.31449-004 (1), 78.9 mm SL, NMV A.31449-005 (1), 66.9 mm SL.

Diagnosis: A smaller species of Syncomistes (recorded up to 120 mm SL, commonly 80–130 mm SL). Syncomistes wunambal sp. nov. differs from all other species within the Syncomistes complex by a combination of the following characters: lower jaw distinctly pointed when viewed from below, making a ‘V-shape’ in individuals> 65 mm ( Fig. 5c ), rounded in individuals <65 mm; mouth subterminal; teeth flattened; asymmetric, ‘triangleshaped’ with posterior margin angled outwards at 45° and anterior edge straight, widest point of tooth closest to mid-point, slight anteriorly pointed hook at tapered tip ( Fig. 6d ); jaw of adults (> 65 mm) as wide as it is long or slightly longer when viewed from below; dorsal profile straight from dorsal origin to shallow notch on upper jaw; body often with 5–6 straight dark stripes running horizontally along sides; overall colouration gold; usually 2 tooth rows on upper jaw and 2 rows on the lower jaw; longest dorsal fin spine usually <11.0 % SL; 2nd dorsal ray usually longest; longest anal fin spine usually <13.0 % SL; restricted to the Mitchell River that drains the northern Kimberley Plateau.

Description: See Table 29 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–XIII), rays 12 (10–12); anal fin spines III, rays 8 (7–8); caudal fin rays 12+8+7+11 (10–12+8+7+9–12, n = 10); pectoral fin rays 14 (14– 15); pelvic spines I, rays 5; vertebrae 11+14=25 (11+14–15 = 26–27, n = 10); lateral line scales 49 (47–52); scales above lateral line 10 (10–11); scales below lateral line 17 (15–19); pre-dorsal scales 16 (14–17); cheek scale rows 3 (3–4); caudal peduncle scales 29 (29–30); gill rakers on first arch 8+18 = 26 (8–11+15–19 = 24–29); opercular spines 2; preopercular spines 8 (7–14).

See Table 30 for a summary of morphometric variation by type material and other material examined and Table S23 morphometric variation across all specimens combined. Smaller species of Syncomistes . Body slightly laterally compressed, dorsal profile more steeply angled than ventral profile, which is horizontal. Dorsal profile begins with concave notch behind tip of snout that rises steeply for short distance, then straight or slightly convex to inter-orbital, straight or slightly convex along nape to dorsal fin origin, convex until behind base of last dorsal ray, then horizontal to caudal fin base. Ventral profile straight or slightly convex on underside of head, straight or convex from back of head to anal fin origin, then 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 27.2 (25.8–29.2) % SL; body depth at anal fin origin 24.8 (23.0–26.5) % SL; caudal peduncle length 19.1 (16.9–27.9) % SL; caudal peduncle depth 11.5 (11.1–12.1) % SL; pre-anus length 65 (62.4–67.4) % SL. Head length 28.9 (26.8– 30.4) % SL; head pointed. Snout length 43.4 (39.2–47.2) % HL; upper-jaw length 31.8 (27.7–36.4) % HL; jaws equal throughout development; jaw width 31.2 (29.2–35.2) % HL; lower jaw distinctly V-shaped in adults and rounded in juveniles (<65 mm) when viewed from below, as long or longer than it is wide (Morphotype 3; Fig. 5c ). Mouth subterminal with horizontal angle in lateral profile. Narrow, continuous upper lip fold, and very narrow lower lip fold that is discontinuous across the ventral midline. Upper lip more fleshy than lower lip. Lower lip fleshy posteriorly, reducing anteriorly until no fold present. Teeth on outer row of upper jaw 96 (61–100) number varying with size, 10.1 (6.5–10.7) / mm when standardised with upper jaw length; teeth on outer row of lower jaw 71 (56–101) number varying with size, 10.1 (6.5–10.7) / mm when standardised with upper jaw length. Teeth laterally compressed, short and narrow relative to Syncomistes , asymmetric, ‘triangle-shaped’ with posterior margin angled outwards at 45° and anterior edge straight, widest point of tooth closest to mid-point, slight anteriorly pointed hook at tapered tip (Tooth Morphotype 2; Fig. 6d ); teeth fitted close together and overlapping, laterally pointed in lower jaw, extending beyond outer edge of lip. Outer row of large teeth with 3 (2–4) inner rows of smaller teeth on both jaws, embedded in a jelly-like gum. Toothless medial, dorsally oriented hump present at symphysis of lower jaw, opposite toothless region of upper jaw. Orbital diameter 21.2 (18.3–25.1) % HL; interorbital width 29.2 (27.2–31.3) % HL; inter-orbital smooth and not scaled; post-orbital length 39.9 (37.4–41.8) % HL. Lower opercular spine is longer and more robust than upper opercular spine, sometimes extends beyond edge of opercular membrane; preopercular spines serrate, longest and most robust on apex of preopercle, reducing 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 scale rows 2 at mid-point, progress from 1–2 anteriorly to 2–4 posteriorly; 6th (5th–6th) dorsal spine longest, length 10.7 (10.0–11.5) % SL; progressively shorter towards first and last dorsal spines; last dorsal spine fully joined to first dorsal ray by membrane; 4th (2nd–4th) dorsal ray longest, length 11.9 (10.1–13.3) % SL; dorsal margin of rayed portion rounded to tip of last ray; dorsal fin base length 50.2 (48.1–53.1) % SL; dorsal fin length 55.3 (53.0–57.3) % SL; pre-dorsal fin length 39 (36.6–40.6) % SL. Anal fin origin immediately posterior to base of last dorsal fin spine; terminates at base of last ray; anal fin sheath scales 3 at mid-point; 2nd anal spine longest, length 12.7 (11.2–13.7) % SL; 2nd (1st–2nd) anal ray longest, length 14.7 (12.6– 17.2) % SL; rays progressively shorter towards last ray; margin of rayed portion rounded; anal fin base length 14.4 (13.5–15.7) % SL; anal fin length 21.2 (19.8–22.7) % SL; pre-anal fin length 69.5 (67.7–71.6) % SL. Caudal fin slightly emarginate; upper caudal lobe length 21.8 (19.8–23.8) % SL; middle caudal ray length 16.3 (14.6–18.0) % SL. Pectoral fin length 18.6 (17.3–20.3) % SL; pre-pectoral fin length 28.9 (26.7–31.0) % SL. Pelvic spine length 8.8 (4.4–10.1) % SL; 2nd (1st–3rd) pelvic ray longest, length 17 (16.0–18.4) % SL, then progressively shorter; pelvic fin length 18.6 (18.0–19.3) % SL; pre-pelvic fin length 38.3 (37.2–40.8) % SL.

Colour when fresh: Body gold overall with an olive green sheen. Body darker dorsally, almost white along the midventral line. Body colouration sometimes interrupted by 5–6 dark, slightly wavy, almost straight, lines; same as S. trigonicus . A horizontal silver or gold stripe running below eye to snout, and a dark spot is present on upper edge of gill cover. Scales on body have a dark posterior band of pigmentation.

Anal fin with a basal blotch extending posteriorly on anterior rays. Caudal fin membranes dusky or gold with clear edges. Dorsal fin membranes gold or black with clear edges. Soft dorsal may exhibit dark stripe running the length of the fin, close to the base. All other fins clear.

Colour when preserved: Juveniles and adults uniformly dark brown to grey with hints of pale colouration becoming more dominant towards the ventral region. Mostly pale brown when viewed ventrally. Lateral line is distinctly pale in colouration. Dorsal and caudal fins uniformly dark brown. Pectoral, pelvic and anal fins light brown with yellowish tinge. Black blotch sometimes present on anal fin. No preserved specimens retained horizontal striping.

Distribution: See Fig. 29 . Occurs throughout the Mitchell River catchment in the northern Kimberley region, Western Australia.

Ecology: Adults prefer riffle and run habitat, and may form shoals in deep slow water around snags. Juveniles predominantly reside in riffle habitat. Found in clear waters, over rocky substrates, often where algae is abundant. Reproductive ecology is not known. Diet primarily consists of filamentous algae that is scraped off rocks with specially modified teeth.

Comparison: Broadly similar morphological grouping to S. kimberleyensis and S. trigonicus based their shallow body depth, the presence of a short notch behind the upper lip, a straight dorsal profile between the notch and the dorsal fin during all stages of development, and an extended V-shaped jaw in adults that is longer than it is wide (lower U-shaped in juveniles <65 mm).

Very similar in appearance to S. trigonicus , but can be distinguished by generally having two teeth rows in the upper and lower jaw in adults rather than three. The relative length of the longest dorsal fin spine 10.7 (10.0–11.5) % SL and longest anal fin spine 12.7 (11.2–13.7) % SL is also less than in S. trigonicus , and the body colouration is distinctly golden rather than brown when fresh. When preserved, pectoral, pelvic and anal fins have a yellowish tinge rather than being uniformly dark brown.

Etymology: Named wunambal , to be treated as a noun in apposition, for the Wunambal tribe and language group from the Mitchell River area, in which the fish is found.

Remarks: Specimens known now as Syncomistes wunambal were originally considered to be a population of S. trigonicus (Vari 1978) , however, no specimens from the Mitchell River population were analysed in the description. Syncomistes wunambal has a parapatric distribution, nested within S. trigonicus populations in the Moran River (Roe River Catchment) to the West and the King Edward and Drysdale rivers to the east. The Mitchell River is highly isolated from the neighbouring catchments by the rugged coastline, evidenced by the lack of shared species between the neighbouring catchments ( Morgan et al. 2011a). Furthermore, the vast majority of the catchment (~ 80 %) lies above the 80-meter-high Mitchell Falls which acts as a further barrier to fish migration, evidence by even fewer species above the falls compared to below ( Morgan et al. 2011a). Populations of narrowrange endemic species that are nested with the geographic range of a widespread sister species have been also been observed in other Australian freshwater fauna (e.g. Cherax cainii Austin & Ryan 2002 and C. tenimanus Smith, 1912 , see Morgan et al. (2011b) for distributions; and Nannoperca vittata Castelnau, 1873 and N. pygmaea Morgan et al. 2013 , see Morgan et al. (2011b) for distributions). The pattern can arise when geographic variation leads to the splitting of a subdivided population into reproductively isolated units. Models of reproductive isolation have shown that rapid parapatric speciation on the time scale of a few hundred to a few thousand generations is possible even when neighbouring subpopulations periodically exchange several individuals ( Gavrilets et al. 2000). Syncomistes wunambal does not overlap with the range of any congenerics.

Figures

FIGURE 5.

FIGURE 6.

FIGURE 28.

FIGURE 29.

Tables

TABLE 29. Summary of meristic variation in Syncomistes wunambal sp. nov. (values for number of teeth of upper and lower jaw are per mm of jaw length).

	Holotype	Paratypes (N = 9)
Character		Mode	Mean	Min.	Max.	S.D.
DS	12	12	11.9	11	13	0.60
DR	11	12	11.4	10	12	0.73
AS	3	3	3.0	3	3.0	0.00
AR	7	8	7.6	7	8	0.53
PecR	14	14	14.2	14	15	0.44
PelS	1	1	1.0	1	1	0.00
PelR	5	5	5.0	5	5	0.00
UUCR	12	11	11.1	10	12	0.57
UBCR	8	8	8.0	8	8	0.00
LBCR	7	7	7.0	7	7	0.00
LUCR	11	11	10.7	10	12	0.82
LLSc	48	50	49.2	47	52	1.56
LD	10	10	10.3	10	11	0.50
LA	18	17	16.7	15	19	1.22
PDSc	17	15	15.4	14	17	1.13
DSSc	2	2	2.0	2	2	0.00
ASSc	3	3	3.0	3	3	0.00
CScR	3	3	3.2	3	4	0.44
CPSc	30	29	29.3	29	30	0.50
GRup	8	10	9.6	8	11	0.88
GRlow	18	17	17.0	15	19	1.32
GRtot	26	26	26.6	24	29	1.59
PcV	11	11	11.0	11	11	0.00
CV	14	14	14.1	14	15	0.32
TV	25	25	25.1	25	26	0.32
LDR	4	3	2.9	2	4	0.60
LDS	6	6	5.6	5	6	0.53
LAR	2	2	1.8	1	2	0.44
LAS	2	2	2.0	2	2	0.00
LPR	2	2	1.9	1	3	0.60
Tup	8.7	10	10.5	9	11	0.84
Tlow	6.5	10	9.9	8	10	0.76
TRup	2	2	2.2	2	3	0.44
TRlow	2	2	2.2	2	3	0.44
OS	2	2	2.0	2	2	0.00
PS	7	8	8.9	7	14	2.67

TABLE 30. Morphometric variation in Syncomistes wunambal sp. nov. (values are percentages of denominators in ratios, except for SL).

	Holotype	Paratypes (N = 9)
Character		Mean			Min.	Max.	S.D.
SL (mm)	103.5	78.2			62.5	101.0
BDd / SL	28.0	27.7			25.8	29.1	0.89
BDa / SL	26.5	24.6			23.0	26.0	0.92
CPL / SL	27.9	18.1			16.8	19.0	0.68
CPD / SL	12.1	11.5			11.1	12.0	0.31
HL / SL	29.5	28.9			26.8	30.4	1.31
OD / HL	19.7	21.4			18.3	25.1	1.97
IoW / HL	29.2	29.2			27.2	31.3	1.43
PoL / HL	38.4	40.0			37.4	41.8	1.33
SnL / HL	44.3	43.3			39.2	47.2	2.97
JLup / HL	36.1	31.3			27.7	36.4	2.67
JW / HL	31.8	32.0			29.2	35.2	2.17
PDFL / SL	40.1	38.9			36.6	40.6	1.36
PPecL / SL	29.0	28.9			26.7	31.0	1.16
PPelL / SL	37.7	38.4			37.2	40.8	1.17
PAL / SL	63.3	65.2			62.4	67.4	1.57
PAfL / SL	67.7	69.7			67.8	71.6	1.19
DFBL / SL	53.1	49.9			48.1	52.0	1.38
DFL / SL	57.0	55.1			53.0	57.3	1.50
DFRL / SL	10.1	12.1			10.2	13.3	1.24
DFSL / SL	10.2	10.8			10.0	11.5	0.56
AFBL / SL	14.6	14.4			13.5	15.7	0.70
AFL / SL	21.7	21.1			19.8	22.7	0.84
AFSL / SL	11.5	12.8			11.2	13.7	0.70
AFRL / SL	12.6	15.0			13.4	17.2	1.37
PecL / SL	19.5	18.5			17.3	20.3	0.87
PelL / SL	18.8	18.6			18.0	19.3	0.46
PelSL / SL	9.1	8.7			4.4	10.1	1.70
PelRL / SL	17.9	17.0			16.0	18.4	0.68
CLLup / SL	22.6	21.7			19.8	23.8	1.33
CLLmid / SL	16.3	16.3			14.6	18.0	0.93