Japanese Blenny

Head without cirri and crest. Lower end of gill opening opposite upper margin of pectoral fin. Sensory pores in infraorbital and interorbital canals mostly 8 and 3 respectively. Lateral line usually 7 to 11. Horizontal stripes on body distinct in male, but somewhat obscure in female.

Oviparous, distinct pairing (Ref. 205).

Dorsal spines (total): 11 - 13; Dorsal soft rays (total): 19 - 24; Analspines: 2; Analsoft rays: 20 - 26

Adults occur in coastal and brackish waters among rocks and mangroves (Ref. 9710). Oviparous. Eggs are demersal and adhesive (Ref. 205), and are attached to the substrate via a filamentous, adhesive pad or pedestal (Ref. 94114). Larvae are planktonic, often found in shallow, coastal waters (Ref. 94114). Highly tolerant to adverse environmental conditions, self-reproducing population living between rocks in natural oil seeps in Venezuela (Ref. 56126).

Adults occur in coastal and brackish waters among rocks and mangroves (Ref. 9710). Oviparous. Eggs are demersal and adhesive (Ref. 205), and are attached to the substrate via a filamentous, adhesive pad or pedestal (Ref. 94114). Larvae are planktonic, often found in shallow, coastal waters (Ref. 94114). Highly tolerant to adverse environmental conditions, self-reproducing population living between rocks in natural oil seeps in Venezuela (Ref. 56126).

fisheries: of no interest

Omobranchus lineolatus (Kner)

Petroscirtes lineolatus Kner, 1868a:29; 1868b:331 [Candavu].

Graviceps darwini Whitley, 1958:47 [Port Darwin. Northern Territory of Australia].

Description (see also Table 5).—Dorsal fin XI, 19–21 = 30–32; anal fin II, 20–23; both anal-fin spines of males discernible externally; segmented caudal-fin rays 13–14; dorsal + ventral procurrent caudal-fin rays 11–14; vertebrae 10 + 26–29 = 36–39; epipleural ribs 11–13; prenasal pores present; interorbital pores 3; circumorbital pores 8; lateral-line tubes 4–8; lateral-line tubes extending posteriorly to below level of dorsal-fin spine 6–11; gill opening restricted to area dorsal to level of dorsalmost pectoral-fin ray; lower-lip flap present; circumorbital bones 5; lower jaw teeth 22–30; upper jaw teeth 20–27 (Figure 44); no fleshy bladelike crest on top of head of either sex.

COLOR PATTERN.—Head: Pale with 5 dark bands approximately half width of pale interspaces. Anteriormost band extends from anteroventral margin of orbit across mouth, just anterior to angle of jaws, onto chin; 2nd band extends ventrally from eye and is deflected posteriorly on underside of head; 3rd band extends ventrally from posteroventral edge of eye to ventral portion of head; anterior 3 bands meet corresponding bands of opposite side at ventral midline of head; 4th band originates laterally on nape, curves ventroanteriorly, then posteriorly, and extends to point just above anterior end of pelvic girdle; 5th band extends ventrally from near upper end of gill opening to uppermost branchiostegal membrane fold. Each pale interspace contains a medial, vertical series of about 3–5 small, dark spots. A large, dark, ovoid spot, slightly smaller than eye, present posterior to eye midway between dorsal origins of 3rd and 4th cephalic dark bands (illustrated specimen, Figure 21a, has spot on left side slightly darker along anterior edge, resembling a posteriorly opening crescent; spot on right side is uniformly dark); spot sandwiched between small, dark, longitudinal dorsal mark and ventral dark blotch that is confluent with upper end of 3rd band. Dark, tear-shaped mark directed posteriorly from dorsoposterior edge of eye. Series of irregularly shaped, well-defined, dark spots less than half pupil diameter along top of head posterior to anterior nostrils. Smaller, less defined, dark blotches and spots extend posteriorly along nape and sides of body below anterior end of dorsal fin.

Trunk: Pale with about 9 or 10 pairs of darker, irregularly vertical bands originating along dorsal-fin base and fading out on approximately ventral quarter of body; anteriorly, banding less defined and paired nature less apparent.

Pectoral Fin: Pale with broad, dark band along base (illustrated specimen, Figure 21a, had band broken into small dorsal spot and large ventral blotch on left side of body). Several small, dark freckles present on fleshy pectoral-fin base and basal part of rays.

Pelvic Fins: Uniformly pale.

Dorsal and Anal Fins: Uniformly dusky with several irregularly placed pale spots, each slightly smaller than pupil of eye; pale spots noticeable only in freshest specimen. Series of dark lines in dorsal fin; each line extending from base of a dorsal-fin ray, along posterior edge of ray to fin margin.

Caudal Fin: Dusky with numerous small, pale spots. Series of 4 short, dark stripes on basal portion of fin just posterior to caudal peduncle; series appears superficially as broad bar. Narrow, longitudinal lines of darker pigment present posteriorly.

The largest specimen available (female, Figure 22) differs from the above description in having the cephalic bands very faint laterally on the head and the spotting in the cheek region intensified into a densely speckled pattern. The dark lines in the dorsal fin are directed slightly more diagonally and cross several succeeding rays, a condition similar to that shown in Kner’s (1868b) illustration of Petroscirtes lineolatus (Figure 21b). The dark lines in the anal fin illustrated by Kner are not present in any of our specimens.

There was no noticeable difference in color pattern between males and females.

GEOGRAPHICAL DISTRIBUTION (Figure 6).—Northern and Western Australia and southern New Guinea. The holotype of O. lineolatus was reported to have come from Candavu, Fiji Islands. As noted in the “Nomenclatural Discussion,” we question the validity of this locality record (also see p. 63 under O. punctatus).

Weber (1913, fig. 114; the same illustration appears in de Beaufort and Chapman, 1951, fig. 53, and we reproduce it in our Figure 3a) illustrated a planktonic larva that he listed as Petroscirtes spec, juv. from Laiwui, Obi, Indonesia (Siboga station 142). He mentioned only one specimen, but there are three, 12.1–13.0 mm SL, in ZMA 109.362 from the same station and locality. Weber’s illustration is representative of these specimens, particularly in the preopercular spination. The bony projections anterior to each dorsal-fin ray element except the anteriormost, which lacks a projection, that Weber portrays are actually external projections of the dorsal-fin pterygiophores. The specimens definitely belong in the tribe Omobranchini (as evidenced by their having only two segmented pelvic-fin rays and hinged dentaries), but it is not possible to identify them with certainty. Based on the following meristics obtained from a radiograph, they could be O. lineolatus or Laiphognathus multimaculatus; dorsal fin XI, 20–21; anal fin II, 20–21 (or 21–22, uncertain), vertebrae 10 + 27–28.

HABITAT.—Little known; taken once from rocky ironstone reef in “salt” water at a depth up to 1 meter; once from rock holes on a reef.

COMPARISON.—Omobranchus lineolatus is separable from most of the other species of Omobranchus only by a combination of characters. It differs from all the other species of Omobranchus except O. aurosplendidus in having modally 11 dorsal-fin spines (all populations of the other species have modally 12 or 13 spines). It is prominently different from O. aurosplendidus in lacking a fleshy crest and in having fewer dorsal- and anal-fin elements and vertebrae. In small specimens of O. lineolatus, the color pattern of the head (Figure 21) renders the species instantly recognizable. It is most likely to be confused with members of the elongatus species group, but only O. rotundiceps of that group ever has as few as 11 dorsal-fin spines. In having the gill opening restricted to the area dorsal to the level of the dorsalmost pectoral-fin ray, O. lineolatus could only be confused with the nominal subspecies, O. r. rotundiceps, which infrequently has more than 3 lateral-line tubes, whereas O. lineolatus usually has more than 4.

NOMENCLATURAL VARIATION.—Variation in meristic characters was noted only in the Okinawa population of O. loxozonus, which tended to have higher averages for most characters (Table 12).

GEOGRAPHICAL DISTRIBUTION (Figure 5).—Southern Japan and Okinawa. Kamohara (1957) reported O. loxozonus as occurring as far north as Kominato, Chiba Prefecture. We have not been able to verify this record and have not, therefore, entered it on the distribution map.

HABITAT.—Little information is available, but some collections have come from shallow, rocky tidepools.

COMPARISONS.—Omobranchus loxozonus is a member of the elongatus species groups (see “Comparisons” under O. elongatus). Within the elongatus species group, O. loxozonus is most similar to O. germaini, which is allopatric. The color pattern on the head and body of O. loxozonus is less contrasty than that usually exhibited by O. germaini, and the number of body bands is less. Where populations of the two species are geographically closest there are marked differences in numbers of fin-rays, vertebrae, and lateral-line tubes (see Tables 5, 10, 12), although overlaps in the ranges for these characters exist.

Omobranchus loxozonus can be most readily distinguished from those species of Omobranchus with which it appears to be sympatric as follows: from O. fasciolatoceps in lacking a fleshy crest, in having the gill opening extending ventrally to opposite the 1st to 4th pectoral-fin rays (versus restricted to area dorsal to dorsalmost ray), and in rarely having as few as 2 interorbital pores (versus rarely having as many as 3 pores); from O. elegans in lacking the dense covering of small, dark spots on the body and in infrequently having as few as 7 circumorbital pores (versus strongly modally 7 pores); and from O. punctatus in having 0–4, rarely more than 3, lateral-line tubes (versus 2–8, rarely fewer than 4 tubes), and in having the gill opening usually extending ventral to the level of the dorsalmost pectoral-fin ray (versus usually restricted to area dorsal to dorsalmost ray and never extending ventrally below dorsalmost ray).

MATERIAL EXAMINED.—JAPAN: WAKAVAMA PREFECTURE: CAS uncataloged (ca. 41); Shirahama, CAS GVF reg. no. 747 (6: 49.5–64.8), GVF reg. no. 748 (ca. 49). KAGAWA PREFECTURE: Toyohama, CAS uncataloged (ca. 51). MIYAZAKI PREFECTURE: Nobeoka, USNM 199520 (7: ca. 34–59.5). TANEGASHIMA: BMNH 1923.2.26.341–50 (6: 37.4–47.8), CAS SU9364 (53.5, presumed holotype of Petroscirtes loxozonus, see Springer and Eschmeyer, 1974), SU9783 (25: 28.8–58.0), USNM 53275 (16:32.7–54.6, including putative holotype of Petroscirtes loxozonus), 70761 (142: 19.4–70.7). OKINAWA: USNM 70763 (4: 34.2–ca. 51), 123770 (ca. 45), 132754 (37.9), 132812 (13: 22.2–42.1), 209269 (2: 27.9–42.5), 209715 (ca. 40).

Omobranchus punctatus (Valenciennes)

Blennechis punctatus Valenciennes in Cuvier and Valenciennes, 1836:286 [le canal de Bombay].

Petroscirtes dispar Günther, 1861:232 [in part; Amoy, China; lectotype designated below].

Petroscirtes semilineatus Kner, 1868b:333 [Candavu].

?Petroskirtes japonicus Bleeker, 1869:246 [Jedo, Japonia].

Salarias decipiens DeVis, 1884b:694 [Cardwell, Queensland Coast].

Salarias helenae DeVis, 1884b:697 [St. Helena, Moreton Bay].

Salarias sindensis Day, 1888:263 [Kurrachee].

Aspidontus dasson Jordan and Snyder, 1902:456 [Wakanoura, Japan].

Petroscirtes kochi Weber, 1908:263 [Merauke-Fluss, Südküste, New Guinea, Brackwasser].

Poroalticus sewalli Fowler, 1931:403 [tide pools at Brighton Beach, Trinidad].

Petroscirtes masyae H. M. Smith, 1934:316 [tide pool on Koh Chula, a rocky islet in the Gulf of Siam off Lem Sing, Southeast Siam].

Omobranchus japonicus scalaius J. L. B. Smith, 1959:232 [Delagoa].

DESCRIPTION (see also Tables 5 and 13).—Dorsal fin XI–XIII (XII in 90.6% of specimens), 19–24 = 31–36; anal fin II, 20–26; one or both anal-fin spines of males not discernible externally; segmented caudal-fin rays 12–14 (13 in 97.9% of specimens); dorsal + ventral procurrent caudal-fin rays 8–16 (rarely 8–11); vertebrae 10–12 + 26–31 = 37–41; epipleural ribs 15–25 (rarely 15–17 or 25); prenasal pores present; interorbital pores 2–4 (3 in 95.6% of specimens); circumorbital pores 6–10 (8 in 92.8% of specimens; 6 or 10 in 0.6% of specimens); lateral-line tubes 2–8 (usually more than 4); lateral-line tubes extending posteriorly to below level of dorsal-fin spine 3–12 (usually 7–11); gill opening either restricted to area dorsal to level of dorsalmost pectoral-fin ray (93.0% of specimens) or extending ventrally to opposite dorsalmost ray; lower-lip flap present; circumorbital bones 4–5 (of 5 specimens examined all had 5 except one specimen with 5 on one side and 4 on the other; the 4 bones resulted from a fusion of the 2nd and 3rd circumorbitals from the anteriormost); lower jaw teeth 22–38 (Figures 49–52); upper jaw teeth 21–33; no fleshy bladelike crest on top of head of either sex.

COLOR PATTERN.—Males: Head: Broad, ventrally flared, dark dusky band running from anteroventral margin of orbit across mouth, just anterior to angle of jaws, onto chin where it joins corresponding band of opposite side; band, interrupted by orbit, continues from dorsoposterior margin of orbit to dorsal midline of head, decreasing in definition. Second broad, dark dusky band present posterior to eye completely encircling head, often faint to absent midlaterally, being represented only by narrow, intensely dark, anterior marginal line, dusky to dark blotch, or curved, diagonal, moderately broad, dark dusky line posterior and ventroposterior to eye. Third broad, dark dusky band extending from dorsal end of operculum to ventral side of head, sometimes confluent with corresponding band of opposite side at ventral midline; band often faint midlaterally on operculum. Snout and interorbital dark dusky with large, irregular, pale blotches or spots anteromedially to eyes. Nape dark dusky with irregular pale spots and blotches anteriorly. Nape posterolaterally with prominent, dark, anteroventrally intensified blotch just anterior to dorsal-fin origin; corresponding blotches on opposite sides often continuous as band, sometimes with dusky blotch present between them middorsally; dark blotches, or band, usually set off by pale margin. Short, nearly horizontal, dark line present at dorsal end of 3rd dark head band.

Trunk: Four or five, more or less parallel, evenly spaced, slightly wavy, dark, horizontal lines present anteriorly on dorsal three-fourths of body; large specimens with lines extending posteriorly for half body length; lines much shorter in small specimens; midlateralmost line on body reaching forward to center of gill opening; dorsalmost line usually, formed from series of 8 or 9 more or less joined horizontal dashes; midlateral 3 lines followed posteriorly by single midlateral series of dusky to dark rectangular blotches, becoming faint posteriorly; all blotches very faint in large specimens; blotches reach far forward in small specimens; some specimens with blotches continued ventrally as very faint, broad, dusky streaks. Dorsal body contour with series of about 11 joined pairs of intensely dark blotches; anteriorly each pair of blotches positioned above corresponding dash in dorsalmost horizontal dark body line.

PECTORAL FIN: Pale with even spread of dark specks of pigment on rays; membranes mostly transparent. Lower half of fleshy pectoral-fin base with faint to prominent, broad, dark dusky bar immediately posterior to branchiostegal membrane; fleshy pectoral-fin base sometimes with dark line along base of fin, particularly dorsally.

Pelvic Fin: Pale with fairly even spread of dark specks of pigment, somewhat darker proximally.

Dorsal Fin: Transparent to slightly dusky with narrow, dark dusky stripe one-third distance up from base; stripe becoming faint to absent posteriorly. Dorsoposterior portion of fin often dusky. Some specimens with distal edge of fin narrowly dusky.

Anal Fin: Pale dusky to dark dusky, especially distally; ray tips abruptly pale, particularly anteriorly on fin.

Caudal Fin: Pale to dusky with vertically oriented pair of slightly darker blotches at base of fin; dusky streak directed posteriorly from each blotch in some specimens.

Females: Similar to males except: horizontal lines on body less distinct; midlateral, rectangular, dark blotches well developed, remaining distinct more posteriorly, often appearing associated with more dorsal row of dashes and row of blotches on dorsal body contour giving body banded appearance (banded appearance present in some males but not usually to extent of that in females).

Geographical Variation: This species is fairly consistent in color pattern throughout its range. A great deal of variation occurs in head pattern (particularly midlaterally) largely due to the indistinctness of the markings posterior to the eye and on the cheek. Specimens in the three lots examined from Ceylon, however, were somewhat distinct in the following particulars: head with dark markings behind eye usually joined to form reticulated pattern; dorsalmost horizontal line on body not usually clearly broken into dashes, posterior ends of next two lines confluent with second and first midlateral blotches respectively; blotches on lateral body midline less angular, extending slightly dorsally and ventrally, particularly in smaller specimens; series of paired blotches on dorsal body contour extending onto base of dorsal fin in many specimens.

GEOGRAPHIC VARIATION (see also “Color Pattern”).—Population variation was noted in most meristic characters of O. punctatus (Table 13). There is no particular pattern shown by these variations. The Western Australian populations exhibit an increase in the number of precaudal vertebrae that is duplicated by no other population of O. punctatus. Similar increases in number of precaudal vertebrae are also exhibited by the Western Australian populations of O. germaini and O. r. rotundiceps, but no others. The factors causing this peculiar type of variation are unknown.

Although covariance comparisons of numbers of jaw teeth (Table 14) were not feasible for all populations of O. punctatus, several of the populations exhibited significant differences in numbers of teeth. In general, if one sex of one population exhibited a significant difference in the number of teeth in one jaw from that exhibited by the same sex of another population, then both sexes of each population differed significantly in numbers of teeth in both jaws; where the differences in the other jaw or other sex were not significant they were nearly so.

GEOGRAPHIC DISTRIBUTION (Figure 7).—Recorded from one restricted locality (Delagoa Bay) in the western Indian Ocean, otherwise common from the Persian Gulf to Japan and eastern Australia. One questionable record from the Fiji Islands (discussion below). Common in Trinidad and in Panama around the Atlantic entrance to the Panama Canal and in lower Gatun Locks. (For discussion of Atlantic distribution see p. 59.)

Yazdani (1963) reported Petroscirtes kochi (= O. punctatus) from Phoenix Bay, Port Blair, Andaman Islands. We are unable to verify this identification and have not entered the record on the distribution map for O. punctatus. Chyung (1954) reported O. punctatus (as Dasson) from Masan, Korea, and (1961) identifiably illustrated it. We are unable to translate the Korean localities in the 1961 publication but based on the 1954 locality, together with the 1961 illustration, we have included the 1954 Korean locality on Figure 7.

HABITAT.—Shallow, often murky, marine and occasionally brackish waters at or close to the shore-line or near river mouths or mangroves. In tidepools and areas with rocks (often encrusted with barnacles or oysters), sparse corals, and sargassum. Once taken at a salinity of 28 0/00 in Gatun Locks, Panama. Reported (Lachner, Robins, Courtenay, 1970) common around docks in Trinidad.

COMPARISONS.—Omobranchus punctatus is a member of the banditus species group (see “Comparisons” under O. banditus). It differs from the other members of its group as follows: from all in overall color pattern and in never having a fleshy crest on the head, and from O. banditus in having a lower-lip flap. It is otherwise distinguishable from the other species of Omobranchus only by a combination of characters, although when its color pattern is strongly manifested the species is recognizable at sight. The narrow, dark longitudinal lines on the anterior quarter of the body occur in no other species of Omobranchus.

NOMENCLATURAL

分布於印度-太平洋區，由波斯灣至斐濟，北至日本等。台灣分布於北部、澎湖及蘭嶼等海域。

小型魚類，僅具學術研究價值。

體長橢圓，稍側扁；間鰓蓋骨之腹後側有突起，向後超過上舌骨之後緣。頭頂無冠膜，頭無鬚；上下唇平滑，具下唇膜，上下頜各側後方具一大犬齒；鰓裂向腹面延伸至胸鰭第1軟條基部。D. XI-XII, 22-24； A. II, 24-26； P. 13；V. I, 2。背鰭無缺刻，背、臀鰭與尾柄相連。雄魚頭部有3條暗帶環繞，眼前、眼後與鰓蓋各具一條；頸部兩側具黑斑；體側背部前3/4有3-5條黑色縱線，隨後有深色橫帶；鰭皆為灰黑色，胸鰭基部有一大暗斑；雌魚與雄魚同，但體側縱紋不明顯，橫帶則很清晰。

分佈於岩石區的潮池。

Omobranchus punctatus, the muzzled blenny or the spotted oyster blenny is a species of combtooth blenny found in coral reefs in the Pacific and Indian Ocean.