Aulopareia unicolor (Valenciennes, 1837)

Larson, Helen K. & Jaafar, Zeehan, 2022, A review of the gobiid fish genus Aulopareia (Gobiidae: Gobiinae) with description of a new species from Kuwait and discussion of the status of Gobius cyanomos Bleeker, Zootaxa 5155 (4), pp. 493-516 : 508-512

Aulopareia unicolor (Valenciennes, 1837)

( Figs 12–13 ; Tables 1–3 , 7 )

Gobius unicolor Valenciennes (ex Kuhl & van Hasselt) in Cuvier & Valenciennes, 1837: 88 (Java).— Bauchot et al. 1991: 40 (Java).

Gobius chlorostigmatoides Bleeker 1849: 6 , 26 (Madura Straits near Surabaya and Kammal, Java, Indonesia).

Gobius phaiomelas Bleeker 1849: 28 (Madura Straits near Surabaya and Kammal, Java, Indonesia).

Gobius masoni Day 1873: 107 ( Bombay, India).—Day 1876: 287 ( Bombay); Whitehead and Talwar 1976: 161 ( Bombay); Ferraris et al 2000: 299 ( Bombay).

Rhinogobius atripinnatus Smith 1931: 45 (Gulf of Thailand off mouth of Tachin River, central Thailand).— Koumans 1940: 130 (Gulf of Siam).

Acentrogobius chlorostigmatoides — Zheng 1989: 347 (Zhujiang River); Rainboth 1996: 197 (Mekong delta; tidal zone in Cambodia).

? Acentrogobius microps Chu and Wu 1963: 420 , fig. 316 (in Chinese, not seen).

Aulopareia unicolor — Roberts 1993: 43, fig. 47 (Lebak rivier); Kottelat et al. 1993:142 (Sundaland, Thailand, China); Larson in Randall & Lim 2000: 635 (South China Sea); Larson & Murdy 2001: 3595 (western central Pacific); Larson et al. 2008: 146 (no recent material from Singapore); Rainboth et al. 2012: 102, Fig. 2105 ( Vietnam, Minh Hai, Song Gang Hao); Tran et al. 2013: 137 (West Pacific); Kottelat 2013: 400 (South-East Asia); Prokofiev 2016: 807 (Cai River, Vietnam); Akel & Rizkalla 2017: 65 (Port Said, Egypt); Kimura et al. 2018: 257 (Ha Long Bay, Vietnam); Nagao Natural Environment Foundation 2021: 437 (Mekong Basin in Vietnam).

Creisson chlorostigmatoides — Chen et al. 1996: 2–3 (Tzengwen River, Shi-liao, Pei-men, Tainan County, Taiwan).

Aulopareia atripinnatus —Larson in Randall & Lim 2000: 635 (South China Sea); Larson & Murdy 2001: 3595 (western central Pacific).

Aulopareia spilopterus — Larson & Murdy 2001: 3595 (western central Pacific).

Amoya chlorostigmatoides —Zhong in Wu et al. 2008: 253–254 ( China).

Aulopareia atripinnata — Kottelat 2013: 399 ( Tha Chin, 13°30’N 100°17’E) .

Aulopareia masoni — Kottelat 2013: 400 ( India: Bombay).

Aulopareia spiloptera — Kottelat 2013: 400 ( Tha Chin, 13°30’N 100°17’E) .

Material examined. INDIA: NMW 33926, 52 mm SL male, syntype of Gobius masoni , Bombay, F. Day collection; RMNH 1883, 61 mm SL male, probable syntype of Gobius masoni , Bombay, F. Day collection; AMS B.8099, 72.5 mm SL male, syntype of Gobius masoni , Bombay, F. Day collection; BMNH 1889.2.1.3378, 1(62), Bombay, F. Day collection; CAS 29748, 6(32.5–60), Cochin, Kerala, seine-netted off beach, 12 August 1964; ZRC 53892, (35), Canning, West Bengal, coll. A. Rao, 2003; NTM S.15650-002, Hooghly River, West Bengal, coll. H. Bleher, 1998. INDONESIA: MNHN A.1120, holotype of Gobius unicolor , 63 mm SL female, Java, coll. Kuhl and Van Hasselt; RMNH 6168, 13(39–66), possible syntypes of Acentrogobius chlorostigmatoides and holotype of Gobius phaiomelas, Surabaya, Kammal , near Freto Madurae, coll. P. Bleeker. MALAYSIA: NTM S.14740-001, 1(44), Station 6, Straits of Malacca, 3°15.165’ S 101°15.495’E 6 m, coll. S.W. Zgozi, 28 March 1998; NTM S.16642-003, 1(49 [poor condition]), Station 6, Straits of Malacca, coll. C. V. Chong, March 1998; NTM S.16081-001, Matang mangrove forest, Perak State, coll. A, Tan, 2005. THAILAND: USNM 90321, holotype of Acentrogobius atripinnatus , 47 mm SL female, off Tachin River, Gulf of Siam, coll. H. Smith, 14 December 1927. USNM 119527, 1(68), off Tachin River, Gulf of Siam, coll. H. Smith, 14 December 1927. QM I.39150, 2(66–86), Songkhla Lake, Songkhla Province, coll. Z. Jaafar, 14 October 2012; CAS 53250, 3(52–75), sand bars and channels nearby Songkhla fish market, coll. Swarny, A. Fehlmann and R. R. Rofen, 2–4 November 1957; USNM 119528, 2(41–52.5), Singora, outlet of Tonle Sap, coll. H.M. Smith, 8 October 1927. CHINA: CAS 53256, 5(54–70), local fish market, Portuguese Macao, coll. R.L. Bolin, 21 March 1958; NTM S.16286-003, 3(53–69), Qi’ao Island, Pearl River, Guandong Province, coll. R. Cui and party, 2005.

Seen but no data taken: CAS 53239, 1 (35), Gulf of Thailand 10° 26’45”N 99° 15’27”E, 0–1 m, sand flat, beach bordering mangrove forest, coll. Pairojana and party, 23 May 1960 ; CAS / SU 4991 , 8 (45.7–79.0) Guangdong Province, Shantou (Swatow), South China Sea, China, coll. A.M. Fielde [no date, probably 1880s] .

Diagnosis. A species of Aulopareia with second dorsal fin rays usually I,10; anal fin rays usually I,9; pectoral fin rays 17–21; lateral scales 31; TRB 9–14; predorsal scales 16–25; three preopercular pores present; cheek naked; opercle scaled on dorsal half; predorsal with cycloid scales extending anteriorly to behind eyes; mental frenum with rounded lobes; gill opening extending to under opercle; preserved specimens pale brown to brownish with about four rows of small black spots along lower part of body and bluish spots on upper part of body mostly above pectoral fins; blackish fins.

Description. Based on 41 specimens, 33–86 mm SL; morphometrics from 37 specimens ( Table 6 ).

First dorsal fin VI; second dorsal fin I,10–11, usually I,10; anal fin I,8–10, usually I,9, pectoral fin rays 17–21; segmented caudal fin rays 17, in 9/8 pattern; usually 8/7 branched caudal rays; lateral scales 24–31; TRB 9–14, usually 10–11; TRF 10–15; predorsal scale count 16–25; circumpeduncular scales 12–14, usually 12; gill rakers 1–3 + 8–11. Gill opening extending forward under mid-opercle; reaching only just under opercle in a few specimens. Gill rakers on outer face of first arch slender but short; rakers outer face of second arch low and stubby.

Body compressed, more so posteriorly. Head rounded, wider than deep, cheeks inflated and fleshy in adult males, which also may have low fold on cheek below eye; HL 25.9–36.1% (mean 29.0%) of SL; head depth 57.7–77.7% (mean 68.1%) of HL; head width 60.0–77.7% (mean 68.2%) of HL. Mouth terminal, oblique, forming an angle of about 40° with body axis; lower lip and chin tip anteriormost; jaws reaching below mid-eye; upper jaw length 35.7–55.3% (mean 45.7%) of HL. Body depth at anus 17.5–26.6% (mean 22.0%) of SL. Caudal peduncle compressed, length 18.9–27.2% (mean 21.8%) of SL; caudal peduncle depth 10.8–16.6% (mean 13.4%) of SL. Lips smooth at sides, finely fimbriate anteriorly; lower lip fused to underside of head on either side of broad bilobed mental frenum. Eyes small, rounded, width 13.0–23.4% (mean 18.0%) of HL. Snout rounded, 11.7–32.4% (mean 24.6%) of HL; posterior nostril rounded to irregular in shape, with low rim, placed close to front of eye; anterior nostril in wide short tube, placed very close to upper lip. Interorbital broad, flat and fleshy, 9.2–23.1% (mean 16.5%) of HL.

First dorsal fin low, pointed, third spine (second or fourth spine less often) usually longest, its tip just falling short of second dorsal fin origin when depressed; third spine 13.8–19.1% (mean 15.9%) of SL. Second dorsal fin low, with posteriormost rays longer than anterior rays, fin pointed posteriorly. Anal fin low; fin pointed posteriorly. Second dorsal fin rays reaching back to base of caudal fin in adults; anal fin rays falling well short of caudal fin at all sizes. Pectoral fin short, oval, central rays longest, 18.2–25.8% (mean 21.8%) of SL; all rays branched, fin reaching back to above anus. Pelvic fins fused, oval to slightly pointed, not quite reaching anus, 17.3–29.1% (mean 22.7%) in SL. Caudal fin short, rounded to slightly pointed posteriorly, 24.3–35.8% (mean 29.7%) of SL.

Teeth in upper jaw in 3–4 rows across front, narrowing to two rows at side of jaw; outermost row of teeth at front of jaw large, stout and conical, widely spaced; teeth at side of jaw relatively small; teeth in innermost row small, sharp and closely packed. Teeth in lower jaw in 3–4 rows across front and two rows at side of jaw; outermost row of teeth at front of lower jaw largest, stout and conical, with 1–2 enlarged curved teeth at angle of jaw; teeth along side of jaw all small and pointed. Tongue tip blunt or rounded.

Predorsal scales small, cycloid, extending anteriorly to behind eyes; cheek naked; opercle covered with small cycloid scales on dorsal part; pectoral fin base with cycloid scales; prepelvic area with relatively large cycloid scales; body scales larger, ctenoid anteriorly to behind pectoral fin. Ventral part of abdomen with cycloid scales.

Sensory canals and pores. Sensory canals with nasal pore close to each posterior nostril, no anterior interorbital pore, single posterior interorbital pore, no postorbital pore, long slit-like pore behind eye (this canal and elongate pore is supported by sphenotic bone); two additional pores in oculoscapular canal over preopercle and two pores in short canal over opercle; three preopercular pores present ( Fig. 12 ). Sensory papillae in longitudinal pattern ( Fig. 12 ).

Freshly dead colour. Described from photos by K.K. Bineesh, Gianluca Polgar and P.T. Rajan. Head and body pale brown to blackish brown head always darker than body, with about six staggered rows of bluish round spots (not always visible) on anterior part of body, spots on lower half of body darkening to black behind pectoral fin and fading out posteriorly to about middle of anal fin; in large specimens, blackish spot present at rear of large pale spot on each scale ( Fig. 13 ). Opercle may have overall iridescent bluish tinge. Sensory papillae in rows on head dark brown, contrasting with head colour. Dorsal fins plain blackish; second dorsal darker than first, almost black. Anal, pectoral and pelvic fins black. Caudal fin black with several rows of small whitish and black spots near base and small indistinct blackish blotch on upper base of fin.

Preserved colour. Head and body pale yellowish brown to dark brown (depending upon preservation), with 3–4 rows of small dark brown to blackish spots on lower half of body, beginning behind pectoral fin and fading out posteriorly to about middle of caudal peduncle (or further forward); in large specimens, blackish spots can be seen to be at rear of large pale spot on each scale; scattered iridescent pale blue to whitish blue rounded spots may be present on dorsal half of body, most spots present above pectoral fin (pale blue spots may not be visible, depending upon preservation) ( Fig. 13 ). Underside of head pale brown to almost whitish. Diffuse dusky grey to blackish blotch over and above rearmost section of oculoscapular canal over opercle (blotch rarely distinct). Sensory papillae in rows on head may be brownish to dark brown. Dorsal fins dusky to blackish. Anal, pectoral and pelvic fins dark grey to blackish. Caudal fin dusky to blackish with several rows of small whitish and black spots near base and small blackish blotch on upper base of fin (may not be distinct).

Distribution and Habitat. Known from mangroves and estuarine habitats; from India to China. It appears to be common in large rivers and creeks in the Vietnam Mekong system and can co-occur with A. koumansi ( Nagao Natural Environment Foundation (2021). The species has also been reported from the Mediterranean Sea, probably ship-assisted ( Akel and Rizkalla 2017).

Remarks. Kottelat (2013) stated that two Kuhl and van Hasselt specimens were present in RMNH 1919, in addition to the holotype, which they also collected (MNHN A.1120). Neither Roberts (1993) nor Bauchot et al. (1991) refer to these specimens and neither of us have seen them (note that RMNH collections were inaccessible at time of writing). The RMNH specimens are also cited in Fricke et al. (2021). Kottelat (2013) states “Valenciennes based his description on a specimen in MNHN and on the figure sent by Kuhl and van Hasselt. Unless it can be demonstrated that this specimen is the same as the one on the drawing, there is no holotype but a series of syntypes ”. Roberts (1993: 43) gives 88 mm SL for the figured specimen (his fig. 47). Valenciennes’ description refers to one individual and refers to the Kuhl and Van Hasselt painting at the end of the description. We thus agree with Kottelat that the two RMNH specimens are syntypes as is the MNHN type.

Acentrogobius chlorostigmatoides Bleeker, 1849 , is illustrated in Bleeker (1988: Plate 9, fig. 11), based on RMNH 4525 (not a type). Gobius phaiomelas has not been illustrated and the type is thought to be the largest specimen (66 mm SL) within RMNH 6168, among the putative syntypes of Gobius chlorostigmatoides .

Acentrogobius microps Chu and Wu , in Chu, Chan & Chen, 1963, referred to as Amoya microps by Zhong in Wu & Zhong (2008) is an Aulopareia based on Zhong’s 2008 redescription and his figures 114 and 405. The description (roughly translated from the Chinese) provides enough information to show that the species most resembles A. unicolor in scalation (no cheek scales and upper half of opercle scaled, 26–28 lateral scales, 22–23 predorsal scales) but the colour description is very brief and does not quite agree with Zhong’s Figure 114. The species may be valid, but until the types (in Shanghai, holotype SFI 59-0048) can be examined, its status remains uncertain.

Rainboth (1996) recorded this species from Cambodia, but Nagao Natural Environment Fund (2021) reported that they could not verify this record during their 2007–2013 field surveys.

Figures

FIGURE 12. Sensory pores and papilla rows in Aulopareia unicolor, CAS 53255, 54 mm SL female. Scales on nape an indication only.

FIGURE 13. Aulopareia unicolor, preserved adult and two juveniles, ZRC 538333. Photo by Heok Hui Tan.