Germain'S Blenny

Head with wavy vertical lines, pale-rimmed dark spot just behind eye, oblique brownish bands, and curved white lines on side. Dorsal rays usually XIII, fin slightly notched between spinous and soft portions; 3 mandibular pores on each side; gill opening extending ventrally from slightly above pectoral-fin base to opposite 6th pectoral ray; head crest and cirri absent; last dorsal and anal rays attached by membrane to caudal fin; body depth about 5.8 in SL. Maximum size to 7.8 cm TL (Ref. 90102).

Oviparous, distinct pairing (Ref. 205).

Dorsal spines (total): 12 - 14; Dorsal soft rays (total): 18 - 23; Analspines: 2; Analsoft rays: 21 - 26

Inhabits shallow reefs, in crevices just below level of low tide (Ref. 36661).

Adults inhabit shallow reefs, in crevices just below level of low tide (Ref. 36661). Found in tidepools and rocky shores, solitary or in small groups (Ref. 90102). 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).

Omobranchus germaini (Sauvage)

Petroscirtes germaini Sauvage, 1883:158 [Nouvelle-Caledonie].

Graviceps alexanderi Whitley, 1945:33 [Fremantle, Western Australia, living in holes in wharf piles].

DESCRIPTION (see also Tables 5 and 10).—Dorsal fin XII–XIV (XIII in 84.6% of specimens), 18–23 = 31–36; anal fin II, 21–26; both anal-fin spines of males discernible externally; segmented caudal-fin rays 13–14 (13 in 98.8% of specimens); dorsal + ventral procurrent caudal-fin rays 11–18 (12–16 in 97.5% of specimens); vertebrae 10–11 + 28–32 = 38–43; epipleural ribs 11–15 (12–14 in 97.4% of specimens); prenasal pores present; interorbital pores 2–5 (3 in 96.7% of specimens); circumorbital pores 7–10 (modally 8 or 9); lateral-line tubes 0–8 (0 in only 1 of 243 specimens); lateral-line tubes, when present, extending posteriorly to below level of dorsal-fin spine 1–10; gill opening varying from restricted to area dorsal to level of dorsalmost pectoral-fin ray to extending ventrally to opposite 6th ray (extending below level of 4th ray in only 3 of 230 specimens); lower-lip flap present; circumorbital bones 4–5 (of 7 specimens examined all had 5 except 1 specimen with 4 on one side and 5 on the other; the 4 bones resulted from a fusion of the posteriormost 2 circumorbials); lower jaw teeth 16–28 (Figure 48); upper jaw teeth 14–25; no fleshy bladelike crest on top of head of either sex.

COLOR PATTERN.—Males: Head: Ventral half to one-third with about 4 irregular, moderate to broad, evenly spaced bands; anteriormost band joining corresponding band from opposite side across ventral surface; remaining 3 bands variable, with none to all bands joining corresponding band of opposite side across ventral surface. Anteriormost band extends from chin to anterior edge of orbit; remaining 3 bands originate ventral and posterior to ventral extremity of orbit. Pale spaces between bands slightly broader than adjacent bands; spaces divided by vertical series of narrow to moderately broad dashes or broken lines. Ventral surface with irregular transverse series of uninterrupted and interrupted dark bands. One or more irregularly positioned, short, broad, dark lines posteriorly in branchiostegal region. Dorsoanteriorly darkened, dome-shaped area posterior to eye between circumorbital and preopercular series of cephalic sensory pores; vertically elongate, intense, black spot, about as broad as pupil diameter, at level of pupil just inside anterior margin of dome-shaped area. Operculum with large, dorsoanteriorly inclined, dusky area enclosed by pale border; border sometimes incomplete posteroventrally; dark blotch sometimes present above pale border. Short, dark band just anterior to gill opening. Trunk portion of gill opening darkly pigmented. Head and nape uniformly dusky dorsally.

Trunk: Unpaired dark band in area covered by appressed pectoral fin followed posteriorly by 7 or 8 pairs of dark, equally broad bands. Bands slant posteroventrally below lateral midline; unpaired band and first 2 band pairs slant anterodorsally above midline; remaining bands slant posterodorsally above midline. Bands usually well developed ventrally, occasionally faint to absent; bands broken into dark mottling or spotting on dorsal quarter of body. Posterior bands often poorly developed with posteriormost band usually represented as elongate midlateral spot. Each band with intensification of pigment midlaterally, sometimes continuing ventrally as medial sliver of dark pigment (intensifications appear as series of paired spots in faded specimens). Unpaired band and band pairs encircled by narrow, pale margins, paler than interspaces separating band pairs; interspaces between band pairs broader than individual bands. Narrow, dark stripe on body along dorsal-fin base, sometimes broken into series of spots in faded specimens.

Pectoral Fin: Pale with uniform spread of dark specks of pigment. Fleshy pectoral-fin base crossed by 1–3 dark or dusky bars; anteriormost bar darkest, occasionally extending onto head.

Pelvic Fin: Pale to slightly dusky.

Dorsal Fin: Pale with series of dark, irregular stripes; stripes broad, inclined anterodorsally on anteror portion of fin, less defined, narrower, inclined dorsoposteriorly on posterior portion. Posterior 3rd of dorsal fin uniformly dusky. Some specimens with a series of more-or-less joined, intensified, black blotches, usually extending from 8th to 11th segmented ray (variable in range between 7th and 13th rays); others with single large, dusky to intense dark spot in same area. Distal margin of fin with narrow white edge.

Anal Fin: Dusky, slightly darker distally with narrow, white, distal margin. Small, poorly denned, dark spot on membrane at fin base posterior to every 2nd ray.

Caudal Fin: Uniformly pale. Caudal peduncle with 2 moderately sized spots at fin base, 1 just above and 1 just below lateral midline of body; pigment streak from each spot continued posteriorly onto fin.

Females: Color pattern as in males but considerably less intense; body bands very narrow, ventral portions faint to absent. Fin pigment usually faint; spot or spots between 7th and 13th segmented dorsal-fin rays faint or absent.

Geographic Variation: Taiwan: Dark pigment on dorsal portion of body generally better developed; lines and marks in pale interspaces above lateral midline of body intensified, producing mottled appearance on trunk and posterior body. Dark blotches present on top of head and nape. Females with better development of spots (normally characteristic of males) in region of 7th to 13th dorsal-fin rays. Ventral edge of caudal fin occasionally dusky.

Hong Kong and Northern and Western Australia: Trunk and posterior body mottled dorsally, similar to Taiwan specimens. Anterior end of dorsal fin with narrow, anterodorsally inclined, dark stripes.

GEOGRAPHIC VARIATION (see also color pattern).—Population variation was noted in most meristic characters of O. germaini (Table 10). In general, the Australian populations have the highest average numbers of elements for each character, but within Australia most of the Arhnemland population’s averages are noticeably low and closer to those of the extra-Australian populations.

The Western Australian populations exhibit increases in numbers of precaudal, caudal, and total vertebrae. Similar increases are exhibited by the Western Australian populations of O. rotundiceps, whereas the Western Australian populations of O. punctatus exhibit an increase in the number of precaudal vertebrae, but not caudal or total vertebrae. Increase in number of precaudal vertebrae was not encountered in any other species of Omobranchus. It is noteworthy that three species of Omobranchns should each exhibit increases in number of precaudal vertebrae in about the same geographic area, even if presently inexplicable.

Although covariance comparisons of numbers of jaw teeth (Table 11) were not feasible for all populations of O. germaini, it was found that significant differences in numbers of lower teeth occurred between females of the Hong Kong and southwestern Australian (Shark Bay to Perth) populations and between the southwestern Australian and Queensland populations. For upper jaw teeth, significant differences occurred between females of the Hong Kong and northwestern Australian (Montebello to Maud), between Hong Kong and southwestern Australian, and between the southwestern Australian and Queensland populations; the comparisons between the northwestern Australian and Queensland populations were almost significant.

GEOGRAPHIC DISTRIBUTION (Figure 6).—Western Pacific Ocean from northern Taiwan south to the Tropic of Capricorn on the Australian east coast and Perth on the Australian west coast; New Caledonia.

HABITAT.—Found in shallow coastal waters and tide pools around rocks and coral, usually at normal seawater salinities. At least 1 collection from rocks at the mouth of a small stream. Usually in calm waters but common on the open-ocean (high-energy) side of One Tree Island in areas inundated at high tide and subjected to the action of breakers.

COMPARISONS.—Omobranchus germaini is a member of the elongatus species group (see “Comparisons” under O. elongatus). Males and sometimes females of O. germaini are distinguishable from all other Omobranchus species by the mosaiclike pattern of dark spots and bars that is often present on the underside of the head (Figure 29e). Within the elongatus group, O. germaini is most similar to O. loxozonus, which is allopatric. The color pattern on the head and body of O. germaini is usually more contrasty and the number of body bands is usually larger than in O. loxozonus. 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.

NOMENCLATURAL

分布於西太平洋區，由台灣及香港至新加勒多尼亞。台灣分布於北部、東北部及澎湖等海域。

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；鼻管細小；上下唇平滑，具下唇膜；上下頜各側後方具一大犬齒，上下頜齒皆少於30； 鰓裂向腹面延伸達胸鰭第4軟條基部。D. XIII, 18-20； A. II, 22-23； P. 13； V. I, 2。背鰭無缺刻，背鰭最後軟條與尾柄以鰭膜相連，臀鰭不與尾柄相連。 雄魚眼後方有一暗斑，頭部下方有4-7條不規則灰黑帶，頭頂與頸部有黑斑，體側具成對黑褐色橫帶；背鰭灰黑色，有不規則的黑紋，第7-13軟條間具一黑斑；臀鰭黑色，鰭緣白色； 腹鰭與胸鰭灰白色； 尾鰭灰黑色。雌魚與雄魚略同， 但體色較淡，體側橫帶較窄， 頭頂黑斑較淡或消失。

分佈於淺海或低潮帶的珊瑚礁區。

Omobranchus germaini, Germain's blenny, is a species of combtooth blenny found in coral reefs in the western Pacific ocean.