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Kunishima, Taiga, Palla, Herminie P., Tachihara, Katsunori, Maeda, Ken (2022): First Records of an Estuarine Goby Acentrogobius ocyurus (Gobiiformes: Gobiidae) from Japan and the Sulu Sea in the Philippines. Species Diversity 27 (1): 129-138, DOI: 10.12782/specdiv.27.129, URL: http://dx.doi.org/10.12782/specdiv.27.129

Rhinogobius estrellae Maeda, Kunishima & Palla, new species [New English name: Estrella goby] (Figs. 1���5; Tables 2���6) Material examined. Eight males and 16 females from Narra, Palawan Island in the Philippines. Holotype. NSMT-P 140091, male (40.6 mm SL), Estrella Falls, 13 May 2016, coll. K. Maeda, T. Kunishima, and H. P. Palla. Paratypes. NSMT-P 140092, female (38.9 mm SL), same data as holotype; URM-P 49295���49301, 1 male (40.7 mm SL) and 6 females (36.1���40.9 mm SL), same data as holotype; URM-P 49302, female (43.0 mm SL), creek in front of the Estrella Village Barangay Hall, 28 May 2018, coll. K. Maeda, H. Kobayashi, and H. P. Palla; URM-P 49303���48306, 2 males (37.8���39.6 mm SL) and 2 females (36.4���45.3 mm SL), Estrella Falls, 28 May 2018, coll. K. Maeda, H. Kobayashi, and H. P. Palla; WPU-PPC-P 50���54, 1 male (37.5 mm SL) and 4 females (35.5���41.1 mm SL), same data as holotype; WPU-PPC-P 55���59, 3 males (37.3���38.4 mm SL) and 2 females (33.2���37.8 mm SL), Estrella Falls, 28 May 2018, coll. K. Maeda, H. Kobayashi, and H. P. Palla. Diagnosis. Pectoral fin with 14���16 rays (usually 15 rays). Nape and posterior part of occipital region covered by cycloid scales; scaled area extending anteriorly to around a vertical line through posterior margin of preopercle or a little posterior to this line. Longitudinal scales 27���31, predorsal scales 3���11. Number of vertebrae 26. Cephalic sensory pore system usually with B��, C, D(S), E, F, H��, K��, L��, M��, N, and O��, but often lacking one or both side(s) of pore E. Transverse rows of sensory papillae on cheek. In preservative, lateral and dorsal sides of body with dark brown mesh-like markings, snout and cheek with three dark brown stripes, and pectoral fin with dark brown band vertically across proximal part of the upper and middle rays except lower 2���6 rays. In life, upper and middle parts of pectoral-fin base with bright white vertical band. Description. Body nearly cylindrical anteriorly and somewhat compressed posteriorly. Head depressed and larger in male than female (head length 33.5���36.0 vs 30.3���32.9% of SL; Fig. 3). Eyes located dorsolaterally. Mouth terminal and oblique with thick upper and lower lips. Anterior tips of upper and lower jaws almost even or upper jaw slightly protruding beyond lower jaw. Posterior end of upper jaw always exceeding a vertical line through anterior margin of eye. Mouth larger in male than female (upper-jaw length 14.1���16.1 vs 10.5���11.9% of SL; Fig. 3). Anterior nostril short tubular, posterior nostril a pore. Cephalic sensory pore system usually with B��, C, D(S), E, F, H��, K��, and L�� in oculoscapular canal and M��, N, and O�� in preopercular canal, but 5/ 24 specimens lacking one pore C, 2/ 24 specimens lacking both pores C, 7/ 24 specimens lacking one pore E, 5/ 24 specimens lacking both pores E, 3/ 24 specimens having pore G on one side, and 1/ 24 specimens lacking one pore N. One specimen having an additional single pore anterior to another single pore D. Arrangement of cutaneous sensory papillae of head shown in Fig. 4. Cheek having two longitudinal rows of papillae and 4���6 transverse rows both between eye and upper longitudinal row and between upper and lower longitudinal rows. Vertebrae 10+16=26 (n=9) or 11+15=26 (n=1), P-V 3/II II I I 0/9 (n=9) or 3/II I II II 0/9 (n=1). First dorsal fin usually with six spines supported by six pterygiophores, but 1/ 24 specimen with seven spines supported by seven pterygiophores. Second dorsal fin usually with one spine and eight soft rays, but 3/ 24 specimens with one spine and seven soft rays. First- and second-dorsal-fin bases separated each other by a small interval (0.3���3.9% of SL). First dorsal fin rounded, usually almost semi-circular; posterior tips of fin (usually tips of fourth to sixth spines) not reaching second dorsal fin origin (n=13), just touching base of second-dorsal-fin spine (n=6), or exceeding base of second-dorsal-fin spine but not reaching base of first soft ray of second dorsal fin (n=5). Anal fin usually with one spine and eight soft rays, but 3/ 24 specimens with one spine and seven soft rays and 2/ 24 specimens with one spine and nine soft rays. Caudal fin with 17 segmented rays, including 12 (n=3), 13 (n=9), or 14 (n=12) branched rays; posterior margin rounded. Male having larger second dorsal, anal, and caudal fins than female (second-dorsal-fin length 34.6���38.7 vs 27.7���30.2% of SL, anal-fin length 31.3���33.7 vs 24.2���29.3% of SL, and caudal-fin length 28.6���31.7 vs 24.4���28.0% of SL; Fig. 3). Pectoral fin with 14���16 rays (usually 15 rays) (Table 2). Pelvic fin with one spine and five soft rays; pelvic fins joined together to form a cuplike disk with fleshy bilobed frenum. Posterior tip of pelvic fin located below middle of first-dorsal-fin base. Ctenoid scales covering lateral side of body and dorsal and ventral sides of caudal peduncle. Nape and posterior part of occipital region covered by cycloid scales; scaled area extending anteriorly around vertical line through posterior margin of preopercle (above pore H��) or to a little posterior to this line (above area between pores H�� and K��). Other regions in head naked. Belly and first-dorsal-fin base covered with cycloid scales. A few cycloid scales also occurring on trunk behind pectoral fin, along bases of second dorsal, anal, and caudal fins, and on proximal part of caudal fin. Pectoral-fin base and breast (prepelvic area) probably naked (at least invisible without staining by arizarin red; see Suzuki et al., 2016). Longitudinal scales 27���31 (usually 28���30), transverse scales 8���10 (usually 9), transverse scales in caudal peduncle always 7, and predorsal scales 3���11 (Tables 3���5). Colour in preservative (Fig. 1): Background of head and body cream. Head with three dark brown stripes; upper one running on snout and connecting upper lip and eye; lower two running diagonally across cheek and connecting upper lip and posterior margin of preopercle. These stripes often broken-up with gaps, branches, and additional dots. Posterior margin of opercle fringed by narrow dark brown vertical band. Pectoral-fin base dark brown with thin, whitish vertical line along bases of middle and ventral rays. Scales on dorsal and lateral sides of body having dark brown margins forming mesh-like patterns. Darkness of scale margins variable and body often showing four or five dark brown saddles from trunk to caudal peduncle. First and second dorsal fins greyish brown with multiple transparent or pale grey spots on proximal and middle parts. Anal fin pale grey or greyish brown, often darker in males. Caudal fin pale grey or greyish brown with 6���10 dark brown vertical bands, but ventral part lacking these bands. Pectoral fin pale grey or greyish brown with a dark brown vertical band proximally on upper and middle parts. Pelvic fin pale grey or greyish brown. Colour in life (Fig. 5): Background of head and body pale reddish- or yellowish grey but more whitish on ventral side; ventral surface of head and belly often tinged with orange. Dark brown markings on head and body described in ���colour in preservative��� present but more reddish. Background of cheek and opercular region often tinged with greyish blue. Pectoral-fin base black with a bright white vertical band posteriorly on upper to middle parts, and often tinged with greyish blue anteriorly. Background of body tinged with sky blue. First and second dorsal fins reddish brown or orange with many white spots on proximal and middle parts. Anal fin reddish brown or orange but proximal and posterior parts greyish blue. Caudal fin reddish brown or orange with 6���10 translucent or white transverse bands on middle part. Pectoral fin translucent often lightly tinged with orange, and proximal parts of some ventral rays white. Pelvic fin pale orange proximally and light grey or greyish blue distally. Distribution. Rhinogobius estrellae is endemic to Palawan Island, Philippines. Most of the specimens examined were collected from a pool and the lower reaches of a stream below the Estrella Falls (9��21'26"N 118��23'50"E), located where a steep stream from Mt. Victoria (1,726 m) comes out to a large plain in Narra, Sulu Sea-side of the island. This new species was abundant in the pool below the first major fall with many cyprinids and gobies but absent in the reaches above it which are occupied by sicydiine gobies including Sicyopus zosterophorus (Bleeker) and Lentipes palawanirufus Maeda & Palla, and eels of the genus Anguilla Schrank (unidentified to species level). The new species was also found in a creek in front of the Barangay Hall of Estrella Village (9��21'28"N 118��24'58"E), drawing from the stream below Estrella Falls. The stream flows into Malatgao River. When we surveyed a site in the middle reaches of the Malatgao River (9��20'16.7"N 118��27'27.0"E), no Rhinogobius were found there. The water at Estrella Falls was cool even during the hottest dry season (May) in this region (water temperature was 26.5��C when measured on 13 May, 2016), while water in the Malatgao River was warmer (appeared to be nearly 30��C although we did not measure). Etymology. The type locality of the new species is Estrella Falls in Barangay Estrella Village. Therefore, the new species is named as Rhinogobius estrellae, derived from Estrella, and the Latin suffix -e., Published as part of Maeda, Ken, Shinzato, Chuya, Koyanagi, Ryo, Kunishima, Taiga, Kobayashi, Hirozumi, Satoh, Noriyuki & Palla, Herminie P., 2021, Two new species of Rhinogobius (Gobiiformes: Oxudercidae) from Palawan, Philippines, with their phylogenetic placement, pp. 81-98 in Zootaxa 5068 (1) on pages 84-89, DOI: 10.11646/zootaxa.5068.1.3, http://zenodo.org/record/5702104, {"references":["Suzuki, T., Shibukawa, K., Senou, H. & Chen, I. - S. (2016) Redescription of Rhinogobius similis Gill 1859 (Gobiidae: Gobionellinae), the type species of the genus Rhinogobius Gill 1859, with designation of the neotype. Ichthyological Research, 63 (2), 227 - 238. https: // doi. org / 10.1007 / s 10228 - 015 - 0494 - 3"]}

Rhinogobius tandikan Maeda, Kobayashi & Palla, new species [New English name: Tandikan goby] (Figs. 1, 3, 6���8; Tables 2���6) Material examined. Thirteen males and 16 females from Cayulo River, Bahile, Puerto Princesa City, Palawan Island in the Philippines. Holotype. NSMT-P 140093, male (43.6 mm SL), 1 June 2018, coll. K. Maeda, H. Kobayashi, and H. P. Palla. Paratypes. NSMT-P 140094, female (45.7 mm SL), 31 May 2018 coll. K. Maeda, H. Kobayashi, and H. P. Palla; URM-P 49307���49315, 7 males (36.1���46.9 mm SL) and 2 females (37.3���38.9 mm SL), 31 May 2018 coll. K. Maeda, H. Kobayashi, and H. P. Palla; URM-P 49316���49323, 2 males (40.8���44.8 mm SL) and 6 females (35.6���45.2 mm SL), same data as holotype; WPU-PPC-P 60���64, 5 females (30.8���36.5 mm SL), 31 May 2018 coll. K. Maeda, H. Kobayashi, and H. P. Palla; WPU-PPC-P 65���69, 3 males (43.6���46.1 mm SL) and 2 females (39.6���41.3 mm SL), same data as holotype. Diagnosis. Pectoral fin with 16 or 17 rays. Nape and posterior part of occipital region covered by cycloid scales; scaled area extending anteriorly to around a vertical line through posterior margin of preopercle or a little posterior to this line. Longitudinal scales 29���34, predorsal scales 5���13. Number of vertebrae 26. Cephalic sensory pore system usually with B��, C, D(S), E, F, H��, K��, L��, M��, N, and O��, but often lacking one or both side(s) of pore C. Transverse rows of sensory papillae on cheek. In preservative, lateral and dorsal sides of body without clear meshlike markings, obscure markings on cheek, and upper half of pectoral fin with dark brown band vertically across proximal part. In life, pectoral-fin base with a bright white vertical band reaching near bottom of fin. Description. Body nearly cylindrical anteriorly and somewhat compressed posteriorly. Abdomen of male often thin. Head depressed and larger in male than female (head length 32.1���37.4 vs 30.8���33.4% of SL; Fig. 3). Eyes located dorsolaterally. Mouth terminal and oblique with thick upper and lower lips. Anterior tips of upper and lower jaws almost even or upper jaw slightly protruding beyond lower jaw. Posterior end of upper jaw always exceeding a vertical line through anterior margin of eye. Mouth larger in male than female (upper-jaw length 13.3���20.9 vs 10.1���12.7% of SL; Fig. 3). Anterior nostril short tubular, posterior nostril a pore. Cephalic sensory pore system usually with B��, C, D(S), E, F, H��, K��, and L�� in oculoscapular canal and M��, N, and O�� in preopercular canal, but 9/ 29 specimens lacking one pore C, 7/ 29 specimens lacking both pores C, 4/ 29 specimens lacking one pore E, 1/ 29 specimen having two pores E on one side, 4/ 29 specimens having pore G on one side, 1/ 29 specimen having pores G on both sides, and 5/ 29 specimens lacking one pore N. One specimen having combined pores K�� and L�� on one side (to be a groove without roof). Arrangement of cutaneous sensory papillae of head shown in Fig. 7. Cheek having two longitudinal rows of papillae and 3���6 transverse rows both between eye and upper longitudinal row and between upper and lower longitudinal rows. Vertebrae 10+16=26 (n=10), P-V 3/II II I I 0/9 (n=10). All males had damage to the caudal fin, except holotype; 10/ 16 female specimens with damaged caudal fin (Figs. 1, 3). Other fins of male and female sometimes damaged also. First dorsal fin with six spines supported by six pterygiophores. Second dorsal fin usually with one spine and eight soft rays. First and second dorsal-fin bases separated each other by a small interval (0.2���4.4% of SL). First dorsal fin rounded, usually almost semi-circular; posterior tips of fin (tips of fourth to sixth spines) not reaching second dorsal fin origin (N=9), just touching base of second dorsal-fin spine (n=12), or exceeding base of second dorsal-fin spine but not reaching base of first soft ray of second dorsal fin (n=8). Anal fin usually with one spine and eight soft rays, but 4/ 29 specimens with one spine and seven soft rays. Caudal fin usually with 17 segmented rays but 3/ 29 specimens with 16 segmented rays, including 11 (n=1), 12 (n=6), 13 (n=15), or 14 (n=22) branched rays (unknown in four specimens due to fin damage); posterior margin rounded in non-damaged individuals. Male having larger second dorsal and anal fins than female (second dorsal-fin length 33.8���43.6 vs 29.5���35.3% of SL and anal-fin length 30.2���38.3 vs 26.7���32.7% of SL), and nondamaged male with larger caudal fin than female (Fig. 3). Pectoral fin with 16 or 17 rays (Table 2). Pelvic fin with one spine and five soft rays; pelvic fins joined together to form a cuplike disk with fleshy bilobed frenum. Posterior tip of pelvic fin located below middle of first-dorsal-fin base. Ctenoid scales covering lateral side of body and dorsal and ventral sides of caudal peduncle. Nape and posterior part of occipital region covered by cycloid scales; scaled area extending anteriorly around vertical line through posterior margin of preopercle (above pore H��) or to a little posterior to this line (above area between pores H�� and K��). Other regions in head naked. Belly and first dorsal-fin base covered with cycloid scales. A few cycloid scales also present on trunk behind pectoral fin, along bases of second dorsal, anal, and caudal fins, and on proximal part of caudal fin. Pectoral-fin base and breast (prepelvic area) probably naked (at least invisible without staining by arizarin red; see Suzuki et al. 2016). Longitudinal scales 29���34 (usually 30 or 31), transverse scales 8���10 (usually 9 or 10), transverse scales in caudal peduncle always 7, and predorsal scales 5���13 (Tables 3���5). Colour in preservative (Fig. 1): Background of head and body brown dorsally and laterally and cream ventrally. Snout with obscure dark brown stripe connecting upper lip and eye. Cheek often with two obscure, dark brown intermittent lines. Posterior margin of opercle fringed by dark brown vertical band. Pectoral-fin base blackish except cream or pale brown bottom. Four to eight dark brown transverse bars or round blotches aligned along lateral midline of body. First and second dorsal fins pale grey with 3���7 brown horizontal stripes on proximal and middle parts, but anterior half of first dorsal fin lacking this marking. Anal fin greyish brown but light brown proximally. Caudal fin pale grey or greyish brown with 6���11 dark brown vertical bands, but dorsal and ventral parts lacking these bands. Pectoral fin pale greyish brown with a dark brown vertical band proximally on upper half. Pelvic fin greyish brown. Colour in life (Fig. 8): Background of head and body olive green or yellowish grey. Snout with reddish brown stripe connecting upper lip and eye. Cheek with two reddish brown longitudinal intermittent lines and several reddish brown spots. Posterior margin of opercle fringed by reddish-brown vertical band. Pectoral-fin base black or dusky with a large greyish blue blotch anteriorly, and with a bright white vertical band posteriorly. Four to eight, dark brown transverse bars or round blotches aligned along lateral midline of body. Irregularly arranged dark brown markings dorsally on body. Centre of lateral scales tinged with sky blue. First and second dorsal fins light yellowish brown with 3���7 dark brown horizontal stripes on proximal and middle parts and reddish brown on distal part, but anterior half of first dorsal fin reddish brown without clear marking. Anal fin reddish brown or orange but yellowish proximally. Caudal fin reddish brown dorsally and ventrally and whitish with 6���11 dark reddish-brown transverse bands on middle part. Pectoral fin translucent but proximal parts of some ventral rays white. Pelvic fin reddish brown proximally and light grey distally. Distribution. Rhinogobius tandikan is endemic to Palawan Island. It was found only in the Cayulo River, Bahile, northern part of Puerto Princesa City. The Cayulo River is a small stream (length approximately 4 km including 1 km of an estuary) flowing into Ulugan Bay on South China Sea-side of the island. The stream system is surrounded by mountains of about 200���400 m above sea level. Cayulo Falls, composed of a series of small waterfalls, is located at the middle eaches of this stream (10��02'12"N 118��45'03"E). Rhinogobius tandikan was found at both the lower and upper reaches of this waterfall, as well as pools in the middle of the falls. The new species was abundant in this site with many other goby species, cyprinids, and a jungle perch species. Etymology. Tandikan is a local name of Palawan peacock-pheasant, Polyplectron napoleonis Lesson, known as a symbol of Puerto Princesa City. The new goby species is named Rhinogobius tandikan, as it has blue markings on the body, suggestive of the plumage of the Palawan peacock-pheasant, and as the type locality is located in the northern part of Puerto Princesa City. The new specific name is a noun in apposition. Comparison. Rhinogobius similis Gill, 1859 is the only species previously known in the genus having transverse rows of sensory papillae on cheek (Suzuki et al., 2016), and our two new species share this unique feature with R. similis. However, the two species in Palawan are distinguished from R. similis in having fewer rays in the pectoral fin (14���17 vs 18���19), predorsal squamation composed of cycloid scales (vs ctenoid scales), anterior-most dorsal scale located around a vertical line through posterior margin of the preopercle or more posteriorly (vs dorsal squamation reaching anteriorly near the posterior margin of the eye), and proximal part of the caudal fin covered by cycloid scales (vs by ctenoid scales). Rhinogobius estrellae shares many characters with R. tandikan, but the former differs from the latter by having fewer pectoral-fin rays (usually 15 vs 16���17; Table 2), fewer scale counts (longitudinal scales 27���31 vs 29���34, predorsal scales 3���11 vs 5���13; Tables 3, 5), and colourations of the body. In preservative, R. estrellae has dark brown mesh-like markings on the lateral and dorsal sides of the body (vs rather uniformly brown in R. tandikan), three dark brown stripes on the snout and cheek (vs often obscure), and a dark brown vertical band on the proximal part of the upper and middle pectoral-fin rays except lower 2���6 rays (vs this band restricted to upper half of the fin). In life, R. estrellae has a more reddish body than the yellowish or olive green R. tandikan, and the former has a bright white vertical band restricted to the upper and middle parts of the pectoral-fin base while this band reaches nearly the bottom of the fin in R. tandikan. Arrangements of the cephalic sensory pore system are basically the same between the two species, but R. estrellae more often lacks pore E on one or both sides than in R. tandikan (12/24 vs 5/29) while R. tandikan more often lacks pore C on one or both sides than in R. estrellae (16/29 vs 7/24). In addition to the transverse rows of sensory papillae on cheek (present vs absent), there are many differences between the two new species from Palawan and three other Philippine species, R. carpenteri Seale, 1910, R. bucculentus (Herre, 1927), and R. philippinus (Herre, 1927), such as numbers of the vertebrae (26 vs 27���29), first-dorsalfin pterygiophores (usually 6 vs usually 7), first-dorsal-fin spines (usually 6 vs usually 7 in R. bucculentus and 6 or 7 in R. carpenteri and R. philippinus), pectoral-fin rays (14���17 vs 17���20), having fewer scales in the longitudinal scales (27���34 vs 35���43), in the transverse scales (8���10 vs 12���18), and in the transverse scales in caudal peduncle (7 vs 9���11), and presence of scales on belly behind the pelvic fins (vs absent in R. carpenteri and R. bucculentus). The latter three species are distributed in Luzon, northern Philippines (see Discussion). Molecular phylogenetic analysis. In the ML phylogenetic tree using the aligned 16,409 bp of mitochondrial genomes (Fig. 9), the species in Rhinogobius were divided into two robust clades. One clade included R. similis and the two new species from Palawan, while all other species belonged to another clade. Six specimens of R. estrellae and four specimens of R. tandikan formed each well-supported monophyletic clade and were sister species to each other. Rhinogobius similis was a sister to this pair., Published as part of Maeda, Ken, Shinzato, Chuya, Koyanagi, Ryo, Kunishima, Taiga, Kobayashi, Hirozumi, Satoh, Noriyuki & Palla, Herminie P., 2021, Two new species of Rhinogobius (Gobiiformes: Oxudercidae) from Palawan, Philippines, with their phylogenetic placement, pp. 81-98 in Zootaxa 5068 (1) on pages 89-94, DOI: 10.11646/zootaxa.5068.1.3, http://zenodo.org/record/5702104, {"references":["Suzuki, T., Shibukawa, K., Senou, H. & Chen, I. - S. (2016) Redescription of Rhinogobius similis Gill 1859 (Gobiidae: Gobionellinae), the type species of the genus Rhinogobius Gill 1859, with designation of the neotype. Ichthyological Research, 63 (2), 227 - 238. https: // doi. org / 10.1007 / s 10228 - 015 - 0494 - 3","Gill, T. N. (1859) Notes on a collection of Japanese fishes, made by Dr. J. Morrow. Proceedings of the Academy of Natural Sciences of Philadelphia, 11, 144 - 150.","Seale, A. (1910) New species of Philippine fishes. The Philippine Journal of Science, Section A, 4, 491 - 543, pls. 1 - 13.","Herre, A. W. C. T. (1927) Gobies of the Philippines and the China Sea. The Philippine Bureau of Science Monographic Publications of Fishes, 23, 1 - 352, pls. 1 - 30."]}

Stiphodon palawanensis, new species (Figs. 1–5; Table 1) Material examined. 57 specimens (24 males and 33 females, 27.0– 63.9 mm SL) collected from Palawan, Philippines. Holotype. WPU-PPC-P 5, male (62.2 mm SL), Balsahan Stream in the Iwahig Prison and Penal Farm, Puerto Princesa City, Palawan, 18 May 2015, coll. K. Maeda and H. P. Palla. Paratypes. CMK 11966, 2 males (37.3 and 43.1 mm SL) and 8 females (28.5–47.2 mm SL), Malatgao River, Narra, Palawan, 29 September 1994, coll. J. Margraf; CMK 11974, 3 females (41.9–48.5 mm SL), Estrella Falls (tributary of Malatgao River), Narra, Palawan, 29 September 1994, coll. J. Margraf; NSMT-P 45091, 45092, and 45094, 2 males (27.7 and 38.8 mm SL) and female (36.6 mm SL), Iwahig River, Puerto Princesa City, Palawan, 13 November 1988, coll. K. Matsuura; URM-P 31438, female (27.0 mm SL), Nagsagoiri River, Palawan, 9 August 1985, coll. S. Shokita; URM-P 31439, 6 males (34.1–36.8 mm SL) and 7 females (32.4–36.2 mm SL), Papait River, Palawan, 9 August 1985, coll. S. Shokita; URM-P 31440, 2 females (38.6 and 40.7 mm SL), Iraan River, Palawan, 5 August 1985, coll. S. Shokita; URM-P 31441, 6 males (31.3–41.4 mm SL) and 3 females (30.7–39.1 mm SL), Tagbariri, Palawan, 9 August 1985, coll. S. Shokita; URM-P 48659 –48662, 2 males (46.2 and 51.1 mm SL) and 2 females (41.1 and 47.2 mm SL), Barake Stream (tributary of Aborlan River), Barangay Magbabadil, Aborlan, Palawan, 15 May 2015, coll. K. Maeda and H. P. Palla; URM-P 48663 –48666, 2 males (59.7 and 63.9 mm SL) and 2 females (58.5 and 63.6 mm SL), same data as holotype; WPU-PPC-P 2 –4, 2 males (52.6 and 59.2 mm SL) and female (46.3 mm SL), Barake Stream (tributary of Aborlan River), Barangay Magbabadil, Aborlan, Palawan, 15 May 2015, coll. K. Maeda and H. P. Palla; WPU-PPC-P 6–9, male (59.4 mm SL) and 3 females (57.5– 62.1 mm SL), same data as holotype. Diagnosis. Second dorsal fin usually with one spine and nine segmented rays, pectoral fin usually with 15 segmented rays; first dorsal fin pointed in male; relatively large caudal fin (26–34 % of SL) in male; premaxilla with 45–71 tricuspid teeth, dentary with 2–6 (male) or 1–4 (female) symphyseal teeth and 45–79 unicuspid horizontal teeth; nape and posterior part of occipital region covered by cycloid scales; 9–11 dusky transverse bars laterally on trunk and tail; first dorsal fin gray or dusky after preservation (orange or reddish brown in life) without any distinct markings, having a line of black blotches (male) or a black band (female) on distal part of second dorsal fin; pectoral fin without clear markings. Description. Morphometric measurements given in Table 1. Body elongate, cylindrical anteriorly and somewhat compressed posteriorly. Head somewhat depressed with a round snout protruding beyond upper lip. Anterior nostril tubular and short, posterior nostril round or oblong, not tubular. Mouth inferior with upper jaw projecting beyond lower jaw. Upper lip thick with small medial cleft. Premaxillary teeth 45–71, fine and tricuspid. Dentary with canine-like symphyseal teeth (number of teeth 2–6 in male, 1–4 in female) and a row of unicuspid horizontal teeth enclosed in fleshy sheath (number of teeth 45–79). Larger fish having more premaxillary and horizontal teeth (Fig. 2). Urogenital papilla in male rounded with one cleft at posterior tip; that in female rectangular, bearing one small projection at each corner of the posterior margin. TABLE 1. Morphometrics of Stiphodon palawanensis, expressed as a percentage of standard length. D 1, first dorsal fin; D 2, second dorsal fin; A, anal fin; C, caudal fin; P 1, pectoral fin; P 2, pelvic fin. First dorsal fin with six spines, except two specimens with five spines; second dorsal fin usually with one spine and nine segmented rays (one specimen with one spine and eight segmented rays). In female, first dorsal fin rounded, almost semicircular, usually second and/or third spines longest, but its posteriormost tip never extending to origin of second dorsal fin. In male, first dorsal fin spines elongate (usually fourth spine longest) and posteriormost point of first dorsal fin (tip of fourth spine) extending to base of first to sixth segmented ray of second dorsal fin when depressed. Anal fin with one spine and ten segmented rays. In female, usually first or second and second or third segmented rays longest in second dorsal and anal fins, respectively; in male, posterior rays longer than anterior rays (last ray and/or penultimate ray usually longest). Caudal fin usually with 17 segmented rays, including 13 branched rays, posterior margin rounded; caudal fin relatively larger in male than in female (caudal-fin length 26–34 % of SL in male, 21–26 % of SL in female). Pectoral fin with 14 (n= 7), 15 (n= 47), or 16 (n= 3) rays. Pelvic fin with one spine and five segmented rays; pelvic fins joined together to form strong, cuplike disk with fleshy frenum. Scales in a longitudinal series 29 (n= 4), 30 (n= 13), 31 (n= 19), 32 (n= 15, including holotype), or 33 (n= 6); scales in a transverse series 9 (n= 1), 10 (n= 3), 11 (n= 52, including holotype), 12 (n= 1); circumpeduncular scales 15 (n= 1) or 16 (n= 55) (not including one broken specimen). Ctenoid scales covering tail, sides and dorsum of posterior trunk. Pectoral-fin base naked. Small naked area behind pectoral-fin base; some anteriormost scales on lateral sides of trunk cycloid. Belly covered with cycloid scales. Nape and posterior part of occipital region covered by cycloid scales (Fig. 3); in female, scaled area slightly exceeding middle of occipital region; male similar, but sometimes not exceeding the middle. Cycloid scales also occurring on first and second dorsal-fin bases, anal-fin base, caudal-fin base, and proximal part of caudal fin. Cephalic sensory pore system always with A´, B, C, D(S), F, H´, K´, L´, N´, and O´(Fig. 4). Oculoscapular canal interrupted between pores H´and K´. Cutaneous sensory papillae developed over dorsal, lateral, and ventral surface of head (Fig. 4). The largest male and female specimens were 63.9 and 63.6 mm SL (82.9 and 77.9 mm in total length), respectively. Color in preservative. In male, background brown; 9–11 (usually 10) dusky transverse bars laterally and dorsally on trunk and tail. First dorsal fin gray or dusky without distinct markings. Second dorsal fin gray or dusky; each ray having a black blotch surrounded by a translucent margin, these black blotches forming a line along second dorsal fin margin, but posterior part of the fin sometimes lacking this black blotch. Anal fin gray or dusky. Caudal fin with dusky longitudinal band on upper part; dorsal to this band, gray; ventrally along this band translucent; middle and lower parts of caudal fin gray. Pectoral fin pale gray without clear markings, but sometimes with one to four obscure, dusky spots on each of middle rays. Pelvic disk dusky, but margin of anterior and middle parts translucent. In female, background brown or yellowish brown; blackish longitudinal band extending from snout and upper lip to below eye and to middle of pectoral-fin base, band continuing from behind pectoral-fin base to posterior end of caudal peduncle through lateral midline; nine or ten (usually ten) dusky transverse bars laterally on trunk and tail intersecting with the mid-lateral longitudinal band. The longitudinal band often unclear if the transverse bars accentuated, and transverse bars often unclear if the longitudinal band accentuated. Additional blackish longitudinal band above the mid-lateral band from dorsoposterior edge of eye to base of upper procurrent caudalfin rays, but often obscure. First dorsal-fin gray without distinct markings. Second dorsal and anal fins gray with a black submarginal band and translucent margin; the black band on second dorsal fin thicker than that on anal fin. Black blotch on middle of proximal part of caudal fin; other part of caudal fin translucent with a black band (upside-down “L” shape) along dorsal and posterior margins and one to four black vertical stripes on middle part. Pectoral fin pale gray without clear markings, but sometimes with one or two obscure, dusky spots along middle rays. Pelvic fin translucent, but middle parts of rays, membranes, and frenum often dusky, forming a ring in ventral view. Color in life. Body and fin markings of male and female similar to those of preserved specimens, but in male (Fig. 5 a–d), background of body grayish, purplish, or yellowish brown; first and second dorsal fins orange or reddish brown; black blotches on second dorsal fin surrounded by white or yellow margins; anal fin brown, gray, or orange; and dorsal part of caudal fin reddish or yellowish with bluish-white margin. In female (Fig. 5 e, f), first dorsal fin reddish brown; second dorsal fin reddish brown with a black submarginal band and bluish white margin; white spots often lining proximal side of this band; anal fin brown with a black submarginal band and bluish white margin; upper and middle parts of caudal fin fringed by bluish white margin; area between the white margin and the black band orange. Distribution. The new species is currently known only from Palawan, in the western Philippines. All known habitats are streams flowing into the Sulu Sea in the central part of the island (Fig. 6). When we explored the Iwahig River where it flows into the South China Sea at Quezon (Fig. 6) for two days in May 2015, S. palawanensis was not found, but other areas, such as the northern and southern parts of the island, have not yet been explored. Given its amphidromous life cycle with the high dispersal ability of the larvae suggested in this genus (Yamasaki et al., 2007; Maeda et al., 2012 b), and the geographically limited survey made to date, S. palawanensis is expected to be found elsewhere in the region in the future. Ecology. The new species was one of the dominant fish species observed in the middle reaches of Balsahan Stream (Puerto Princesa City) and Barake Stream (Aborlan) in May 2015. Stiphodon palawanensis inhabits pools with a substrate that is a mixture of boulders, gravel, and pebbles with exposed bedrock in some places. It also inhabits rapids. The water was clear. The fish were clinging to the rocks while feeding on algae. When disturbed, they swam to nearby rocks or hid in crevices under or between rocks. The maximum water depth of the sites was 1.5 m in May, but it could reach 3.0 m during the wet season. Normally, that occurs from June to December, while the dry season runs from January to May. In these two sites sampled, two cyprinid species Barbodes palavanensis (Boulenger) and Rasbora everetti Boulenger were very abundant with S. palawanensis. Other common species at these sites were two gobioids, Glossogobius illimis Hoese & Allen and Redigobius sp., and a halfbeak Dermogenys palawanensis Meisner. Etymology. The name of the new species is derived from Palawan, the type locality, and the Latin suffix -ensis. Comparison. The new species was compared with congeners sharing the second dorsal- and pectoral-fin ray counts (one spine and nine segmented rays in the second dorsal fin, and usually 15 or 16 rays in the pectoral fin). Stiphodon palawanensis shares 9–11 dusky transverse bars laterally on the trunk and tail with S. maculidorsalis Maeda & Tan and S. multisquamus Wu & Ni, but it differs from S. maculidorsalis in the lack of clear markings on the pectoral fin (vs. having fine black spots along rays), dorsal markings (black spots scattered dorsally on the head and tail of S. maculidorsalis, but not on S. palawanensis), and predorsal scalation (the posterior part of the occipital region is scaled in S. palawanensis, Fig. 3, vs. an occipital region that is almost naked in S. maculidorsalis); and from S. multisquamus by the lack of distinct markings on the first dorsal and pectoral fins (vs. having a black blotch on the posterior part of the first dorsal fin in males, thick dusky lines along spines of the first dorsal fin in females, and fine black spots along the pectoral-fin rays in both sexes), having a line of black blotches (in males) or a black band (in females) on the distal part of the second dorsal fin (vs. no such black markings), and predorsal scalation of males (posterior part of the occipital region scaled in S. palawanensis, Fig. 3, vs. an occipital region that is almost naked in S. multisquamus). Stiphodon niraikanaiensis Maeda males have black longitudinal bands on the second dorsal and caudal fins, but females lack them. Although a line of black blotches on the second dorsal fin in S. palawanensis males resembles a black band when the fin is not fully open, S. palawanensis differs from S. niraikanaiensis also by the lack of conspicuous markings on the first dorsal and pectoral fins (vs. having black spots), and in the mode of the pectoral-fin ray count (15 vs. 16). Stiphodon palawanensis differs from S. alcedo Maeda, Mukai & Tachihara by having a line of black blotches (in males) or a black band (in females) on the distal part of the second dorsal fin (vs. no such markings), having more premaxillary and horizontal teeth (Fig. 2), and the mode of the pectoral-fin ray count (15 vs. 16); from S. martenstyni Watson (of which only the male holotype is known) by lack of clear markings on the first dorsal fin (vs. having two to five dusky spots along each spine) and having a line of black blotches on the second dorsal fin (vs. lack of it); from S. atratus Watson, S. imperiorientis Watson & Chen, S. ornatus Meinken, S. pelewensis Herre, S. pulchellus, and S. weberi Watson, Allen & Kottelat by lack of distinct markings on the pectoral fin (vs. having many black spots along rays), having a line of black blotches (in males) or a black band (in females) on the second dorsal fin (vs. lack of it), and having more premaxillary and horizontal teeth (Fig. 2); and from S. atropurpureus, S. carisa Watson, S. kalfatak Keith, Marquet & Watson, S. larson Watson, and S. semoni Weber by having a line of black blotches (in males) or a black band (in females) on the second dorsal fin (vs. lack of it), a pointed first dorsal fin in males (vs. rounded, except S. carisa males having a pointed fin), and the predorsal scalation of males (the posterior part of the occipital region is scaled, Fig. 3, vs. an occipital region that is almost naked). Briefly, the new species is most easily distinguished by its unique fin markings: any Stiphodon with a line of black blotches (in males) or a black band (in females) on the distal part of the second dorsal fin, and without distinct markings on the first dorsal and pectoral fins can be identified as S. palawanensis. Other Stiphodon species found in Palawan. During our two-day exploration in the type locality of the new species (Balsahan Stream in the Iwahig Prison and Penal Farm, Sulu Sea side of Puerto Princesa City) in May 2015, two other Stiphodon species were found; three female individuals of S. atropurpureus and one male individual of S. percnopterygionus Watson & Chen (Fig. 6). Two of the three S. atropurpureus individuals were collected (Fig. 7 c) and listed as comparative material in this paper. Stiphodon percnopterygionus was not collected, however a wild individual was identified on site by snorkel based observation of characteristic markings of the body and fins (Fig. 8) and its unique, high triangular first dorsal fin. While S. palawanensis was very abundant, both S. atropurpureus and S. percnopterygionus were rare at this site. Four Stiphodon specimens collected in the Iwahig River at Puerto Princesa City in 1988 have been deposited in the National Museum of Nature and Science (Ibaraki, Japan). The Iwahig is a relatively large river next to the Balsahan Stream. The specimens are composed of three S. palawanensis (NSMT-P 45091, 45092, and 45094) and one S. pulchellus (NSMT-P 45093), but the latter species was not found in our exploration in Balsahan Stream in May 2015. In Barake Stream (Sulu Sea side of Aborlan), the only Stiphodon species found during our one-day exploration was S. palawanensis. All collections from Aborlan and Narra, examined in the present study (CMK and URM), also comprised entirely of individuals of S. palawanensis (Fig. 6). We also explored another river bearing the name Iwahig at Quezon, on the South China Sea side of the island (Fig. 6) in May 2015. Stiphodon pulchellus (Fig. 7 a, b) was abundant, but S. palawanensis could not be found there. Thus, the species composition of any Stiphodon assemblage seems to depend on the location on the island. Stiphodon palawanensis may be the dominant species in some areas, whereas S. pulchellus may be dominant in others. However, because only a small survey effort has been applied at each site and only a small part of the island has been explored so far, comprehensive surveys will be required to understand the distribution of Stiphodon species on Palawan.

Maeda, Ken, Palla, Herminie P. (2015): A new species of the genus Stiphodon from Palawan, Philippines (Gobiidae: Sicydiinae). Zootaxa 4018 (3): 381-395, DOI: http://dx.doi.org/10.11646/zootaxa.4018.3.3