Egglestonichthys bombylios Larson and Hoese, 1997

Ni, Yong, Wu, Hanlin, Chen, Yuange, Chen, Jiajie, Tian, Wei, Chen, Weifeng, Xu, Zhaoli & Zhong, Junsheng, 2024, The first record of Egglestonichthys bombylios (Gobiiformes: Gobiidae) from China with its first fresh colouration information, Zootaxa 5399 (1), pp. 37-51 : 39-47

Egglestonichthys bombylios Larson and Hoese, 1997

English name: Egglestone’s bumblebee goby ( Figs. 1–9 ; Table 2 )

Egglestonichthys bombylios Larson & Hoese 1997: 46 , Figs. 1–3 (type locality: North of Smith Point, Northern Territory, Australia, 29 m depth); Larson & Murdy 2001: 3596 (western central Pacific); Manilo & Bogorodsky 2003: S119 (Arabian Sea); Hoese et al. 2006: 1642 (Northern Territory, Finke Bay to Smith Point, Australia); Larson et al. 2013:196 (Northern Territory, Australia); Prokofiev 2016: 808, Fig. 2d,e (South China Sea, Vietnam); Motomura et al. 2017:198 ( Philippines).

Description. Description based on 28 specimens ranging from 33.8–54.0 mm SL. Counts and proportional measurements are given in Table 2.

D VI –I, 10; A I, 10; P 19–21 (modally 21); V I–5; C 17–20 (in only 6 female specimens), usually 17, in 9/8 pattern; longitudinal scales 33–35; TRB 14–16, usually 15; predorsal scales 29–31, usually 30; Gr 5+10–12; vertebrae (including urostyle) 10+16=26 ( Figs. 3 , 4 ). First dorsal-fin pterygiophore formula 3-22110 ( Fig. 5a ). Fifth–sixth and eighth–ninth pterygiophores of second dorsal fin, as well as the sixth-seventh and eighth–ninth pterygiophores of anal fin are inserted between interneural and interhaemal spaces, respectively ( Fig. 5b ). The hemal spine of the first caudal vertebra is opposite the first and second pterygiophores of the anal fin ( Fig. 5b ). One epural present ( Fig. 6 ) .

Body robust, rounded anteriorly, compressed posteriorly. Dorsal and ventral margins shallow arc. Body depth at first dorsal-fin origin 17.2–20.7% (mean 20.6%) in SL. Caudal peduncle depth is 9.4–11.3% (mean 11.4%) SL. Head medium sized, broad, slightly flat in front, and wider than its depth. Head broad, somewhat wider than body depth; HL 24.2–30.2% (mean 28.4%) in SL. Snout round and blunt, its length 2.0–3.2 times EW; snout end at upper edge of the eyes. Width posterior preopercular margin is 62.5–83.3% (mean 66.7%) HL. Mouth terminal, very oblique, forming ~45º angle with body axis. Jaws subequal, generally reaching to below anterior edge of eye; lower jaw slightly prominent. Upper jaw 31.7–38.7% (mean 36.9%) HL. Lips smooth, upper lip not more than four to five times eye diameter. Eyes small, dorsolateral and located on anterior half of head, with no bony ridge on superior margin of eye. Eye diameter 8.5–11.0% (mean 10.6%) HL. Interorbital space broad and convex, 38.7–44.6% (mean 43.8%) HL, 3.4–5.7 times EW, and 1.2–2.4 times snout length. Chin smooth, without mental fold or barbels. Two nostrils on each side, separated, anterior nostril tubular, placed at the posterior edge of the upper lip; tube short and not oriented downwards and forwards. Posterior nostril rounded and pore-like, located close to upper anterior margin of eye ( Fig. 8b ). Vomer, palatine, and tongue toothless. Tongue tip usually concave and not adnate to floor of mouth ( Fig. 8a ). Jaw teeth arranged in 2–3 rows, with outer rows enlarged, caniniform, and incurve, sparsely arranged, with 7–8 teeth in upper jaw and 14–15 teeth in lower jaw; inner rows small and pointed ( Fig. 8b ). Gill opening usually extending forwards to under opercle or before lower pectoral-fin base. Distinct rounded to pointed lobe on rear edge of branchiostegal membrane, which attached along lateral margin of isthmus. Branchiostegal rays 5. Pseudobranch developed. Gill rakers slight, with rather short and smooth gill rakers on outer face of first arch, longest rakers near angle of arch. Pectoral girdle smooth, without fleshy ridge on anterior edge. Gut short, with one simple loop.

Body and head covered with cycloid scales, mostly larger in central part of flank than on head and other parts of body. Predorsal area, from tip of snout to first dorsal-fin origin, and head, including opercle, preopercle, and upper cheek, covered with scales, except for lower cheek and chin, which are naked. Isthmus, breast, abdomen, and pectoral-fin base are mostly covered with scales.

Lateral line absent. Head sensory canals and pores always absent. Sensory papillae with suborbital row a of four long transverse rows, each of several papillae; longitudinal row b longer, from preopercular groove forwards to medial part of most posterior row 2nd a; c with one transverse row, placed between longitudinal b and d rows; d has one longitudinal row, from preopercular groove forwards to posterior edge of upper lip and connected with ul row. Preoperculomandibular series e uniserial, upwards to connect with longitudinal d and b rows, and to connect with ul row at mouth angle. Preorbital pe with two rows, lower pe downwards to connect with ul row, and upper pe upwards to lower part of anterior nostril. Inferior anterior line pe separated from eye line and extends forwards and upwards to anterior and lower parts of anterior nostril. Many (about 17 – 18) short (2 – 5 papillae) i rows, below e. Mental row f longitudinal on each side of anterior ventral surface of mandible. Sensory papillae on dorsal surface of head are difficult clearly observe as head covered with scales ( Fig. 7 , 9 ).

Dorsal fins separate. First dorsal fin with short base, originating just above and behind pectoral-fin base; spines are soft, fourth to fifth spines are longest, reaching the second dorsal-fin origin in males but not in females, when laid flat. Second dorsal fin with longer base and slightly higher than first dorsal fin. Middle and posterior fin rays are longer and do not reach caudal-fin base when laid flat. Anal fin originates opposite second dorsal fin, its base about equal to its height. Anal-fin origin located below the first second dorsal-fin ray; posterior part of fin longer and not reaching caudal-fin base when laid flat. Pectoral fins broad and long, longer than or equal to HL; posterior margin extending (male) or not extending (female) above anus. No dermal flaps at leading edge of pectoral girdle. Pelvic fin elliptic and shorter than pectoral fin, with base length 1/4 its length. Left and right pelvic fins are fused into disc, and fin membrane is very thin and slightly concave posteriorly. Caudal fin broadly rounded and slightly shorter than HL. Anus anterior to anal-fin origin, opposite second dorsal-fin origin.

Fresh colouration ( Fig. 1 ). Pinkish with six broad, dark brown saddle bars extending to or near the ventral profile; the first on head crossing the eye; the second on nape extending onto the operculum; the third and fourth at level of first- and second dorsal-fin bases extending nearly to ventral profile and onto large portions of the dorsal fins; the last two (merged medially), on the caudal peduncle fully extending to ventral profile with the posteriormost bar partially extending onto the caudal-fin base. Intense yellow on snout, pectoral and caudal-fin bases as well as on the anterior two and posterior two or three second dorsal-fin rays. Pectoral, anal and pelvic fins hyaline; caudal-fin rays slightly tinged in yellow.

Colouration in preservative ( Fig. 2 ). Yellowish tan with six broad, dark saddle bars; colour pattern of fins similar to fresh colouration but with a yellowish tinge.

Sexual dimorphism. Fourth to fifth spines of first dorsal fin reach second dorsal-fin origin when adpressed in males but not in females. Posterior margin of the pectoral fins extends to above the level of anus in males but not in females. Posterior end of the urogenital papilla is round and blunt in females, while is slightly pointed in males.

Distribution. Egglestonichthys bombylios is known from the Arafura Sea and Van Diemen Gulf, northern Australia, off Bombay, India ( Larson & Hoese 1997),Arabian Sea ( Manilo & Bogorodsky 2003), Vietnam ( Prokofiev 2016) and Philippines ( Motomura et al. 2017). In the present study, we collected specimens of this species from Dongshan Bay (Fujian Province) and from Sanmen Bay and Niushan Island (Zhejiang Province). Additionally, we received reports of this species from Toumen Island (May 2018), Zhoushan waters (December 2021) in Zhejiang Province, and from Qidong, Jiangsu Province (October 2021). In China, the species occurs from Dongshan Bay (southern Fujian Province) and the Taizhou coast (Zhejiang Province) in the East China Sea to Qidong Point (Jiangsu Province) on the north bank of the Changjiang estuary ( Fig. 10 ).

Size and habitat. Small fish 30.0– 69.2 mm in SL, inhabiting the inner bays, estuaries, and island waters (Larson & House 1997; Prokofiev 2016; Motomura et al. 2017; present study). In Dongshan Bay, where we collected most specimens, the depth does not exceed 31.6 m. During the period of collection (mid-August and mid-September), the water salinity was 20.1–24.3, the surface water temperature was 29.9–31.1℃ and the pH was 7.98–8.16.

Mitochondrial DNA analysis. The ML tree ( Fig. 11 ) inferred from the mitochondrial genome data is well resolved into three major clades, largely supported by high bootstrap values (100%) and Bayesian posterior probabilities. Notably, E. bombylios is nested with Larsonella pumilus and Priolepis cincta . This group is sister to Priolepis spp. which nest together with Trimma spp. to form a distinct clade. Lesueurigobius friesii , Valenciennea longipinnis , Amblygobius phalaena , Vanderhorstia sp. , Asterropteryx semipunctata and Callogobius spp. form another clade. Finally, Bathygobius spp. and Glossogobius spp. nest together to form an additional distinct clade.

Figures

FIGURE 1. Egglestonichthys bombylios, ECSFRI E230513, 47.0 mm SL, Sanmen Bay, Zhejiang, China: (a) lateral view of the whole body; left views of (b) head; (c) caudal fin; (e) pectoral fin; (f) anal fin; (g) pelvic fins ventral view. Photos by Weifeng Chen.

FIGURE 2. Preserved specimen in glutaraldehyde of Egglestonichthys bombylios, SHOU E201307, 53.2 mm SL, Dongshan Bay: (a) lateral view; (b) dorsal view; (c) ventral view. Photos by Hanlin Wu.

FIGURE 3. X-ray of Egglestonichthys bombylios, ECSFRI E201304, 49.0 mm SL, Dongshan Bay.

FIGURE 4. Skeleton preparation of Egglestonichthys bombylios, ECSFRI E201322, 41.0 mm SL, Dongshan Bay.

FIGURE 5. Pterygiophores of Egglestonichthys bombylios, ECSFRI E201322, 41.0 mm SL, Dongshan Bay. a. first dorsal fin; b. second dorsal fin and anal fin. Abbreviations: NS, neural spine; D1P, pterygiophore of 1st spine of 1st dorsal fin; Numbers 3–8, third–eighth vertebrae; A, first caudal vertebra; B, second caudal vertebra; HS, haemal spine.

FIGURE 6. Egglestonichthys bombylios posteriormost vertebrae and caudal skeleton, ECSFRI E201322, Dongshan Bay, 41.0 mm SL. Abbreviations: PU, preural centrum; EP, epural; HY, hypural; US, urostyle; PH, parhypural; NPU, neural spine of preural centrum; HPU, haemal spine of preural centrum; CINPU, inter-neural spine cartilage of PU; CIHPU, inter-haemal spine cartilage of PU; CPEP, post-epural cartilage; CPHPU, post-haemal spine cartilage.

FIGURE 7. Head of Egglestonichthys bombylios, ECSFRI E201317, 45 mm SL, Dongshan Bay (a) lateral; (b) ventral, and (c) dorsal views. Specimen stained in Cyanine Blue 5R. Photos by Jiajie Chen.

FIGURE 8. Egglestonichthys bombylios, a. tongue tip (ECSFRI E201302, 52 mm SL, Dongshan Bay); b. mouth, left nostrils and eye (B. ECSFRI E201317, 45 mm SL, Dongshan Bay).

FIGURE 9. Semi-diagrammatic illustration of Egglestonichthys bombylios showing pattern of sensory papillae on head: (a) lateral and (b) ventral view. (see description for abbreviations). Drawing by Yuange Chen.

FIGURE 10. Distributional records of Egglestonichthys bombylios along the Chinese coast: collected from Dongshan Bay (★), Fujian Province, and Sanmenwan (▲) and Niushan Island (Q) from Taizhou, Zhejiang Province, reports from Jiaojiang estuary (□) and Zhoushan waters (✚), Zhejiang Province, and Qidong (◇), Jiangsu Province.

FIGURE 11. The molecular phylogeny of Egglestonichthys bombylios and 20 related goby species based on the amino acid sequences of 13 protein-coding genes analysed by Bayesian inference (BI) and maximum likelihood (ML) in the GTR+F+I+G4 model. Micropercops swinhonis and Bostrychus sinensis were assigned as outgroups. The numbers above branches indicate ML bootstrap and Bayesian posterior probabilities, respectively. “*” indicate absence from Bayesian inference (BI) tree.