Ophieleotris aporos was originally described by Bleeker (1854: 59) as Eleotris aporos.After Gill (1863: 270) established the genus Ophiocara based on Eleotris ophicephalusValenciennes, a synonym of Ophiocara porocephala (Valenciennes), E.aporos wasassigned to the genus Ophiocara by Bleeker (1877: 27).Aurich (1938: 132) established a new genus Ophieleotris for O.aporos based on the study of sensory canal pores, arrangement of pit organs and other characteristics. However, his genus has not been used by others but Whitley (1964: 55), as far as it is known to us. Our study on comparative morphology on O.porocephala and O.aporos with other species, listed on p.74, has revealed further different characteristics between two species and other species, some of which can be used for separating O.aporos from the genus Ophiocara and for recognizing the genus Ophieleotris for O.aporos. The characteristics of the two species are listed in Table 1.The most importantcharacteristics of the two genera, Ophiocara and Ophieleotris, in comparison with othergenera listed on p.74 are: 1) The presence of a process on the inner side of themaxillary in Ophiocara (Fig.1A) and the absence in Ophieleotris (Fig.1B).2) Thepresence of oculoscapular canal from nasal to posttemporal with the pores A to Lexcept for G, of preopercular canal with the pores M to Q and three supratemporalsin Ophiocara (Fig.2A);the absence of oculoscapular canal and supratemporals andthe presence of short preopercular canal with the pores N'and O'in Ophieleotris (Fig.2B). 3) 17 segmented caudal fin rays in Ophiocara and 15 segmented caudal finrays in Ophieleotris.4) 26 (or rarely 27) vertebrae and the first and second pterygiophoresof the first dorsal fin are inserted between the third and fourth vertebrae in Ophiocara (Fig.3A);25 vertebrae and the first pterygiophore between the third and fourthvertebrae (Fig.3B) or the first two or three pterygiophores between the fourth andfifth vertebrae in Ophieleotris (Fig.3C).5) The presence of a short, low longitudinalridge on frontal in Ophieleotris (Fig.4A);the absence of the ridge in Ophiocara (Fig.4B).6) The size of a scale of interorbital space of Ophiocara smaller than thatof caudal peduncle;the size of a scale of interorbital space of Ophieleotris larger thanthat of caudal peduncle and the largest of all the genera;the size of a scale of caudalpeduncle of both genera is not different.Although O. porocephala has no suborbitalwhose presence is thought to be an unspecialized characteristic, it has common characteristicsin 1) to 4) with the species with a suborbital, except for the loss of thepore G.Thus O.porocephala closely resembles the species with a suborbital whichare thought to be the most unspecialized species. As for O.aporos, when compared with them, it has no characteristics which are as unspecialized as those found in O.porocephala.
A spawning redd of the salmonid fish was found in the Nigorimizu-sawa of the Oirase River system (40° 41'N, 139°58'E), which flows into the Japan Sea in Aomori Prefecture (Figs.2, 3).More than 1, 700 eyed eggs were obtained on November 21, 1960, from this redd.These eggs measured 5.3-5.9mm in diameter.They began to hatch on November 24.The alevins and fry are described and illustrated in this paper (Fig. 4).The fry, liberated in a small pond (ca.4 m2, 50-80 cm deep), took mainly small crustacea and aquatic larvae of insects and attained 38 43 mm in total length by the next April.These fry are considered as members of either of the genera Salvelinus or Hucho for their characteristic arrangement of the vomer and palatine in the roof of the mouth (Fig.5).Because the fish of Hucho is a vernal spawner in Japan, the present fry must belong to Salvelinus. In the Nigorimizu-sawa, there are two types of char Salvelinus leucomaenis (Pallas), i.e., an anadaomous form and a fluvial dwarf form of the same species.Generally, the former grows up 40 cm or more in total length, however, the latter attains 30 cmat largest and rarely deposits eggs exceeding 300 in number at a single spawning redd.Therefore, the present spawning redd, eggs, alevins, and fry are thought to be of theanadromous char called“Amemasu”in Japanese (Fig.1).The parr marks appear inthe alevins of S.malma (Walbaum) (Blackett, 1968), but not visible in the presentalevins throughout their yolk consuming stage (Fig.4).So, there is no reason toidentify these alevins as S.malma.
In May 11th, 1973, 399 specimens of Stethojulis were collected in Suruga Bay, ofwhich 33 showed color phase of S.interrupta and 366 that of S.kalosoma.In anaquarium, 312 specimens with“kalosoma”pattern were kept at the water temperature18.3-25.1°C.Some of them changed their color pattern to“interrupta”phase, within10 days.Among 312 specimens, 54 (42 died, 12 alive) changed to S.interrupta phaseand 258 remained in“kalosoma”phase (187 died, 71 alive), by July 31, 1973.Duringthe color change, certain specimens took on color patterns resembling S.“trossula”.It was found that individuals of“kalosoma”phase included female, male and indeterminables, whereas those of“interrupta”phase were all males.On the basis ofmorphological characters and color patterns, it was concluded that S.kalosoma andS.trossula are junior synonyms of S.interrupta, and represent different color phasein the course of the sex reversal from female to male.
Fishes of the family Melanostomiatidae previously recorded from Japan include seven species in live genera.In 1972, the junior author found a specimen of Melanostomias albibarba Regan and Trewavas in the northern Pacific (38°58.0'-39°7.5'N, 142°12.8'-142°15.5'E).This specimen here reported represents the first record of the species from Japan.A new Japanese name “Shirohige-hoshieso”is proposed.