Odonteleotris macrodon ( Bleeker, 1853 )

Kobayashi, Hirozumi, Nishigaki, Koji, Saeki, Toshifumi & Maeda, Ken, 2023, First Records of Paloa villadolidi from Japan with a Redescription of Odonteleotris macrodon (Teleostei: Butidae), Species Diversity 28 (2), pp. 165-175 : 166-173

Odonteleotris macrodon ( Bleeker, 1853) ( Figs 1 , 2A , 3A–C ; Table 1)

Eleotris macrodon Bleeker, 1853: 104 (type locality: Hooghly River in Kolkata, India); Bleeker 1857: pl. 2, fig. 1 [plates of Bleeker (1853) separately printed]; Günther 1861: 129 [Calcutta (currently Kolkata), India]; Day 1878: 311, pl. 65, fig. 5 [Bengal, India; Burma ( Myanmar)].

Odonteleotris macrodon : Bleeker 1874: 302; Koumans 1941: 328 [Calcutta (Kolkata) and Bengal, India; Akyab (Sittwe), Myanmar; Nias and Java, Indonesia]; Koumans 1953: 330, fig. 81 [Java, Nias, and Celebes (Sulawesi), Indonesia; Calcutta (Kolkata), India; Akyab (Sittwe), Myanmar; Malaya ( Malaysia); Port Darwin, Australia (with question)]; Talwar and Jhingran 1991: 978 ( India); Kottelat et al. 1993: 186, fig. 272 ( Indonesia); Larson and Murdy 2001: 3577 (list only); Satapoomin 2011: 65 ( Thailand); Kottelat 2013: 394 (list only); Parenti 2021: 23 (list only); Larson and Nguyen 2021: [1] [West Bengal, India; Sulawesi and Sumatra, Indonesia; Malaysia; Myanmar; Thailand (see Remarks)].

Material examined. RMNH. PISC. 4472, male, 110.6 mm SL, holotype of Eleotris macrodon Bleeker, 1853 , Hooghly River in Kolkata , India, coll . P . Bleeker.

Diagnosis. Odonteleotris macrodon is distinguished from all other species of Butidae by a combination of the following characters. Enlarged canine teeth on the upper and lower jaws (five and twelve, respectively); canines placed in the outermost tooth row in the upper and anterior lower jaw, while canines placed in the inner tooth row in the posterior lower jaw. Upper jaw ending below center of the eye. Interorbital sensory pore D paired with wide interval. Fourth infraocular transverse row of sensory papillae crossed with a longitudinal row on the cheek. Longitudinal scales 103; transverse scales 32; predorsal scales 63; transverse scales at caudal peduncle 21; circumpeduncle scales 39. Dorsal-fin rays VI-I, 10; anal-fin rays I, 8; pectoral-fin rays 17. Predorsal length 38.2% of SL; body depth at anal-fin origin 18.4% of SL; eye diameter 3.3% of SL. Unpaired fin rays variegated by small blackish spots; a red spot on the upper part of the caudal-fin base when fresh.

Description. Body elongated and cylindrical anteriorly, somewhat compressed posteriorly ( Fig. 1 ). No bony crests in the interorbital region. Mouth large and superior, and oblique with an approximately 45º upward angle; upper jaw ending below the center of the eye. Snout length greater than eye diameter. Anterior nostrils tubular and posterior nostrils with low rim. Upper and lower jaws with five and twelve enlarged, curved canines, respectively ( Fig. 2A ). Five canines in the upper jaw aligned to the anterior half of the outermost tooth row. Five canines in the anterior half of the lower jaw aligned to the outermost tooth row, while seven in the posterior half aligned to the innermost row. Two to four and one to four rows of small conical teeth on upper and lower jaws, respectively. No teeth on the vomer. Small cycloid scales covering the head and body, except around the snout; no accessory scales. Longitudinal scales 98 on the right side, 103 on the left side; transverse scales 32; predorsal scales 63. Urogenital papilla small and oval-shaped in male. First dorsal fin with six spines; second dorsal fin with one spine and ten soft rays. Anal fin with one spine and eight soft rays; anal-fin origin posterior to the second-dorsal-fin origin. Caudal fin with 17 segmented rays. Pectoral fin with 17 soft rays. Pelvic-fin insertion slightly anterior to the pectoral-fin base. Left and right pelvic fins separated from each other, both with one spine and five soft rays. Ten sensory pores (A′, B, C, D, E, F, G, H, K, and L′) in the oculoscapular canal, three (M′, N, and O) and four pores (M′, N, O, and P) in the left and right preopercular canals, respectively; pore D paired with an interval of approximately half of the interorbital width. Arrangement of the cephalic sensory papillae in transverse pattern: six transverse and two longitudinal rows of the sensory papillae on the cheek.

According to Bleeker (1853: 104–105), the original description, body blackish green dorsally and rosy ventrally. Cheek with 2–4 black bars radiating from the eye. Dorsal and caudal fins with reddish rays variegated by black spots. Dorsal rays of caudal fin bordered with red. Pectoral fin olive; pelvic and anal fins violet. Anterior part of the pelvic fin and lower part of the anal fin bordered with red. A red spot on the upper part of the caudal-fin base. Anal-fin rays also variegated by black spots ( Fig. 3A ). Day (1878) described “a dark ocellus edged with light” at the upper part of the caudal-fin base instead of the red spot ( Fig. 3B ). The holotype observed after more than 167 years of preservation, having uniformly brown head and body without any markings, and pale-brown dorsal, caudal, pectoral, and pelvic fins anal dark-brown anal fin ( Fig. 1 ).

Remarks. The morphology of RMNH.PISC. 4472 corresponds well to that described by Bleeker (1853). Bleeker (1853) noted that the holotype had a total length (TL) of 134 mm, and the specimen was measured as 110.6 mm SL and 132.5 mm TL in our examinations (probably due to shrinkage over time). Although our examination of the holotype shows more canines in the lower jaw (12) than the upper jaw (5), Koumans (1953) reported the opposite arrangement, with more canines in the upper jaw (4–6) than in the lower jaw (4). However, this difference may be due to the fact that he only counted the canines on the outer row of the lower jaw and did not include those on the inner side of the posterior part of the jaw.

Odonteleotris macrodon has been reported in Kolkata, India ( Bleeker 1853); Myanmar ( Day 1878; Koumans 1953; Talwar and Jhingran 1991); Thailand ( Satapoomin 2011); Eastern Java, Nias, and Sulawesi in Indonesia ( Koumans 1953); Malaysia ( Koumans 1953); and Australia ( Hoese 2006), but the distribution should be revised to avoid misidentification. Larson and Nguyen (2021) pointed that a disjunct subpopulation from southern New Guinea and northern Australia may be an undescribed species. Therefore, further examination is required to determine the true distribution of O. macrodon .

Paloa villadolidi Roxas and Ablan, 1940 [New standard Japanese name: Shīsā-haze] ( Figs 2B , 3D, E , 4–9 ; Table 1)

Paloa villadolidi Roxas and Ablan, 1940: 304 , pl. 3 (type locality: Dagupan, Pangasinan Province, Luzon , Philippines) .

Material examined. Seven specimens (19.8–75.0 mm SL) from the Ryukyu Archipelago in southern Japan . Okinawa Island : NSMT-P 143769 , male, 55.6 mm SL, 19 October 2021, coll . H . Kobayashi ; NSMT-P 145828 , female, 53.5 mm SL, 9 July 2022, coll . H . Kobayashi and H . Miyake ; NSMT-P 145829 , female, 75.0 mm SL, NSMT-P 145830 , female, 41.0 mm SL, 13 July 2022, coll . H . Kobayashi and R . Ueda ; URM-P 49659 , male, 55.1 mm SL, 16 October 2019, coll . K . Nishigaki ; URM-P 49660 , female, 31.1 mm SL, 28 August 2014, coll . H . Yagi (used only for fin-ray counts and observations of teeth, cephalic sensory systems, and coloration in life). Ishigaki Island : URM-P 49661 , juvenile, 19.8 mm SL, 28 September 2010, coll . T. Saeki .

Diagnosis. Paloa villadolidi is distinguished from all other species of Butidae by a combination of the following characters. Upper and lower jaws with enlarged canine teeth on their outermost rows; more canines on upper jaw (7–11) than on lower jaw (4–7); no inner row of canines in the posterior half of lower jaw. Upper jaw not extending to anterior margin of eye. Interorbital sensory pore D paired with wide interval. Fourth transverse row of sensory papillae (4) crossed with longitudinal papilla row (b) on the cheek. Longitudinal scales 88–100, transverse scales 32–36, predorsal scales 51–65, transverse scales at caudal peduncle 22 or 23, circumpeduncle scales 40–43. Dorsal fin VI-I, 9–10; anal fin I, 8; pectoral fin 17. Predorsal length 38.4–40.7% of SL; body depth at anal-fin origin 14.6–17.1% of SL; eye diameter 3.3– 5.1% of SL. No distinct markings on the unpaired fins and caudal peduncle.

Description. The morphometric and meristic characters are presented in Table 1. Body elongated and cylindrical anteriorly, somewhat compressed posteriorly ( Fig. 4 ). Head slightly depressed, dorsal profile nearly straight, no bony crests in the interorbital region. Mouth large, superior, and oblique with an approximately 50º upward angle; its end not extending below the anterior margin of the eye. Snout rounded, length longer than eye diameter. Anterior nostrils tubular and extending to anterior margin of upper lip; posterior nostrils oval with low rim and not tubular, located approximately one-third of the distance between the orbit and anterior nostril. The gill opening extends anteriorly to below the posterior margin of the preopercle. Upper and lower jaws with enlarged and curved canines in their outermost tooth row ( Fig. 2B ): 7–11 canines in the upper jaw and 4–7 in the lower jaw; upper jaw always having more canines than lower jaw. Two to four rows of small conical teeth on the upper and lower jaws. No teeth on the vomer. Small and somewhat deciduous cycloid scales covering the head and body, except dorsal surface of head anterior to interorbital pores D, side of snout in front of suborbital papilla row 1, lower jaw, lips, maxilla, gular region, and gill membrane; embedded scales on the cheek; no accessory scales. Longitudinal scales 88–100, transverse scales 32–36, predorsal scales 51–65. Urogenital papilla small and triangular in both sexes.

First dorsal fin with six spines; three anterior spines slightly longer than posterior ones. First and second dorsal fins separated by an interval of approximately eight scales along the dorsal midline. Second dorsal fin with one spine and nine or ten soft rays; length of the spine being the same as those of first to third spines of the first dorsal fin; all soft rays branched and longer than spine; soft rays becoming longer from first to fifth soft rays, similar length in fifth to eighth rays, and ninth ray shorter than eighth. Anal fin with one spine and eight soft rays; length of the spine almost the same as that of the second-dorsal-fin spine; all soft rays branched. Anal-fin origin vertically below the base of second or third soft ray of the second dorsal fin. The posterior tip of the second dorsal and anal fins not reaching the caudal-fin base. Caudal fin rounded with 17 segmented rays, including 14–17 branched rays. Pectoral fin rounded with 17 soft rays; rays not filamentous, tip of the pectoral fin below the base of the fourth or fifth spine of first dorsal fin. Pelvic-fin insertion slightly anterior to the pectoral-fin base. Left and right pelvic fins separated from each other, both with one spine and five soft rays; pointed distal tip of the pelvic fin not reaching middle of interval between pelvic- and anal-fin bases; third soft ray longest. Number of vertebrae 26, including 11 abdominal and 15 caudal vertebrae. P-V 3/ II I I 0/9: three anal-fin pterygiophores forward to the first hemal spine.

Cephalic sensory systems illustrated in Fig. 5 . Oculoscapular canal with 12 pores (A′, B, C, D, E, F, G, H, I, J, K, and L′) and preopercular canal with five pores (M′, N, O, P, and Q′), but one specimen (NSMT-P14769) lacked pore G on both sides; pore D paired with an interval of approximately half of the interorbital width. Arrangement of the sensory papillae transverse pattern: five transverse (1–5) and two longitudinal rows (b and d) of the sensory papillae on the suborbital region and cheek; transverse row 3 in contact with longitudinal row b at the middle ( Fig. 5B ). Twelve transverse rows on underside of head (i), with each row aligned on a ridge. Operculum with an elongated transverse row (ot) along preopercular margin, connecting an oculoscapular transverse row (z) around pore M; an oblique row (os) and a longitudinal row (oi); with their posterior ends not joined.

Approximately 18 small transverse rows (lm) of sensory papillae aligned along the lateral midline of the body ( Fig. 6 ). Two transverse and three longitudinal rows (ld) on dorsal to dorsolateral side of the body: anteriormost row (ld 1) below the base of the third spine of the first dorsal fin; posteriormost row (ld 5) on the posterior part of caudal peduncle. Two transverse rows (lv) on ventral to ventrolateral side of the body: anterior row (lv 1) at middle between posterior end of the pelvic-fin base to origin of anal fin; posterior row (lv 2) above the base of third soft ray of the anal fin. Caudal fin with one transverse row (lct) and three longitudinal rows (lcd, lcm, and lcv).

Color of living and fresh specimens. In five adult specimens (41.0–75.0 mm SL), body and head pinkish brown laterally, and orange dorsally and dorso-laterally ( Fig. 7 ). Throat, breast, and belly white except for a region between the bases of the left and right pelvic fins where brown pigments were distributed. Three obscure, red longitudinal stripes running dorsally, laterally, and ventrally on the body of one specimen (NSMT-P 143769: Fig. 7A ), two stripes running dorsally and laterally of three specimens (NSMT-P 145828–145830: Fig. 7D ), and single stripe running along the lateral midline of another adult (URM-P 49659: Fig. 7E ). Iris brown with an internal gold edge. Two transverse, dark, broad bars may be on cheek radiating from the eye ( Fig. 7C ). First and second dorsal and anal fins translucent with orange or brown spines and soft rays, but proximal parts of the membrane on first (between first and second spines) and second dorsal fins (from origin to end) and anal fin (between spine and first soft ray) brown, and spine of anal fin translucent in one specimen. Caudal and pectoral fins with orange or brown rays; membrane brown proximally and translucent distally. Pelvic fins translucent. In smaller adult specimen (31.1 mm SL), body cream with small melanophores scattered laterally on the body; fins almost translucent.

In a juvenile observed alive in a tank ( Fig. 7F ), body translucent with orange dorsally on head and body, around snout and jaws, and on caudal- and pectoral-fin bases; melanophores scattered on the head and body surfaces. Internal melanophores along the ventral midline from anal-fin base to caudal peduncle. Red blood visible in some internal parts of the head, abdominal cavity, and vertebrae. Fins translucent, but second dorsal and caudal fins having orange or brown pigments. After rearing for approximately seven months in a tank, the transparency of the juvenile body decreased and the internal melanophores disappeared.

Color in ethanol. Head and body brown laterally, dark brown dorsally, and white or pale gray ventrally. One specimen (NSMT-P 143769) with a faint brown longitudinal stripe on the posterior half of the lateral midline of the body ( Fig. 4E ), while the other specimens lacked the stripe. Opercular region white edged. Markings of the fins similar to those of living specimens, but the orange and brown colors turned to gray or dusky brown. On urogenital papilla, males with a stellate black spot at center of papilla ( Fig. 8A ), females with a U shaped distinct line along the outer rim of the papilla ( Fig. 8B ).

Distribution. Paloa villadolidi is distributed in Luzon in the Philippines ( Roxas and Ablan 1940) and Okinawa and Ishigaki islands in Japan (this study). Okinawa Island is the northernmost habitat known for this species.

Habitat. All Japanese specimens were found in the tidal zone within or around mangroves in estuaries. Four of the seven specimens (NSMT-P 143769, 145829–145831) were found hovering in small tidepools around the roots of mangrove trees [ Bruguiera gymnorhiza (L.) Savigny] within the forest at night ( Fig. 9 ). The substrate of the tidepool was mud, and a thalassinid mud lobster, Thalassina anomala (Herbst, 1804) made a burrow system around the tidepool. Other fish species, including Bostrychus sinensis (Lacepède, 1801) , Eleotris melanosoma Bleeker, 1853 , Mugilogobius chulae (Smith, 1932) , and Pisodonophis boro (Hamilton, 1822) were observed in that tidepool. A juvenile specimen (URM-P 49661) was found in a similar tidepool on Ishigaki Island, Japan. URM-P 49569 was found inside a polyvinyl chloride pipe buried in the muddy gravel bottom along the main course of the stream during the daytime. This site was approximately 10 m from the mangrove. URM-P 49660 was collected from the burrow of an unknown builder on a muddy substrate using a suction pump during the daytime.

Roxas and Ablan (1940) did not report the habitat of this species. Therefore, no information is available regarding the habitat of this species in the Philippines.

Japanese name. A new standard Japanese name “Shīsā-haze” is proposed for P. villadolidi based on a specimen from Okinawa Island (NSMT-P 143769). “Shīsā” is a traditional Ryukyuan artifact originating from Chinese guardian lion which has characteristic enlarged canine teeth like those of this species. “Haze” means goby in Japanese.

Figures

Fig. 1. Holotype of Eleotris macrodon Bleeker, 1853 (RMNH.PISC. 4472, 132.5mm SL).

Fig. 2. Dentition in upper and lower jaws of Odonteleotris macrodon (A: RMNH.PISC. 4472, holotype of Eleotris macrodon, 132.5mm SL) and Paloa villadolidi (B: URM-P 49659, 55.1mm SL). UCT and LCT, magnified illustrations of enlarged canine teeth in the upper and lower jaws, respectively.

Fig. 3. Illustrations of specimens of Odonteleotris and Paloa. A, Holotype of Eleotris macrodon from Bleeker (1853: pl. 2); B, E. macrodon from Day (1878: pl. 65, fig. 5); C, O. macrodon from Koumans (1953: fig. 81); D, holotype of P. polylepis from Herre (1927: pl. 4, fig. 3); E: holotype of P. villadolidi from Roxas and Ablan (1940: pl. 3).

Fig. 4. Specimens of Paloa villadolidi from Japan (A: URM-P 49659, 55.1mm SL; B–E: NSMT-P 143769, 55.4mm SL). A–D, Specimens immediately after fixation; E, preserved specimen.

Fig. 5. Sensory pores (open circles with uppercase notations) and neuromast rows (red dots with lowercase notations) in the head of Paloa villadolidi (NSMT-P 143769, 55.4mm SL). A, Dorsal, B, lateral, and C, ventral views. AN, anterior nostril; PN, posterior nostril.

Fig. 6. Neuromast rows (red dots with lowercase notations) of trunk and caudal fin in Paloa villadolidi (NSMT-P 143769, 55.4mm SL).

Fig. 7. Live specimens of Paloa villadolidi from the Ryukyu Archipelago, Japan. A–C, NSMT-P 143769 (55.4mm SL); D, NSMT-P 145829 (41.0mm SL, photo by R. Ueda); E, URM-P 49659 (55.1mm SL); F, URM-P 49661 (ca. 10mm SL soon after collection). White arrows indicate stripes on the body.

Fig. 8. Urogenital papilla of Paloa villadolidi. A, Male (NSMT- P 143769, 55.4mm SL); B, female (NSMT-P 145829, 75.0mm SL). Broken lines indicate the outer edge of urogenital papilla; white arrows indicate the anus; red circles indicate the anal-fin origin.

Fig. 9. A tide pool in mangrove of Okinawa Island in Japan, where four specimens of Paloa villadolidi were collected.