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1.
A new goby species, Stiphodon niraikanaiensis, is described on the basis of three specimens (two females and one male) collected from a freshwater stream in Okinawa Island, Japan. This species can be distinguished from its congeners by nine soft rays in the second dorsal fin, 16 rays in the pectoral fin, a pointed first dorsal fin in male, the premaxilla with 46–50 tricuspid teeth in 27–36 mm SL; no white patch behind the pectoral-fin base in male, the nape and posterior half of the occipital region covered by cycloid scales, broad black band along the distal margin of the second dorsal fin in male, 11 or 12 dusky transverse bars laterally on the trunk and tail of female intersecting with the mid-lateral longitudinal band, several conspicuous black spots on each spine and soft ray on the first and second dorsal fins of female, the anal fin of female lacking remarkable marking, and the pectoral-fin rays with 2–5 and 1–4 black spots, respectively, for male and female. The new species is known only from the type locality.  相似文献   

2.
Sailfin molly (Poecilia latipinna) males possess a large dorsal fin (sailfin) and perform an elaborate courtship display. Females prefer to associate and mate with males of greater body and sailfin size. Evidence supports a single origin for the sailfin species complex from a shortfin ancestor. Unlike sailfin species, males of the shortfin species complex are sexually monomorphic in fin size and exhibit little or no courtship behavior. In this study, we tested the pre‐existing bias and lateral projection area (LPA) hypotheses for sexual selection by examining female mating preferences in the shortfin molly, P. mexicana. Specifically, we presented females with pairs of dummy males differing in: (1) dorsal fin and body size together (holding fin:body size ratio constant); (2) body size (holding dorsal fin size constant); (3) dorsal fin size (holding body size constant); and dorsal fin:body size ratio (holding total LPA constant). Females spent more time near dummies of greater body and dorsal fin size. The preference functions based on the first three sets of stimuli showed a similar pattern: the greater the LPA difference between paired dummies, the stronger the preference for the larger of the two. However, in the fourth experiment, neither fin size, body size, nor any particular dorsal fin + body size combination was preferred. These findings support the LPA hypothesis suggesting that increased LPA is more stimulating to sexually receptive females and that females consequently prefer larger males. Moreover, these data are consistent with results obtained in an identical series of experiments conducted on P. latipinna. The preference for increased male dorsal fin size/LPA by both female P. latipinna and P. mexicana supports the pre‐existing bias hypothesis. Thus, a bias for increased male LPA and consequent selection for enlarged dorsal fins may have preceded the appearance of the sailfin trait within the Molliensia lineage.  相似文献   

3.
WithAcanthodes bourbonensis n.sp. another acanthodian from Lower Permian basins of Europe is described. The new species is similar toAcanthodes gracilis (Beyrich) from Silesia (Poland), but it differs from this and all other species of the genus in the development of the pectoral fins, dorsal fin, anal fin and caudal fin. In pectoral fins, dorsal and anal fin there are different ceratotrichia as supporting elements and pectoral fins are attaching along a row of oblonged large scales. In the caudal fin there is an epichoral appendix first found byHeyler (1969).  相似文献   

4.
A new species of deep‐living dragonet Callionymus omanensis from Oman is described on the basis of a single male specimen collected in a trawl from 500 m depth off the coast of Oman. The new species is characterized within the subgenus Bathycallionymus by having a small branchial opening; head short (3·9 in proportion to standard length); eye large (2·4 in proportion to head length); preopercular spine with a long, upcurved main tip, with a small antrorse barb and a larger antrorse spine, and with a strong antrorse spine laterally at the preopercular‐spine base, ventral margin smooth; first dorsal fin slightly higher than second dorsal fin (male); second dorsal fin distally straight; 17 pectoral fin rays; distal end of caudal fin slightly pointed, with two median unbranched rays bearing short filaments; first dorsal fin with basal black spot reaching from first to fourth membranes, third membrane with an ocellated distal black blotch; second dorsal fin with vertical dark grey bars; distal three‐fourths of anal fin black; upper half of caudal fin with oblique dark grey bars; pelvic fin dark grey, second ray basally with a black blotch. The new species is compared with similar species. Revised keys to callionymid species of the western Indian Ocean and the Red Sea, as well as species of the subgenus Bathycallionymus, are presented.  相似文献   

5.
Pentanchus profundicolus is an enigmatic shark, characterized by a single dorsal fin. The holotype, which was collected in 1909 from the Philippines, had remained the only known example of the species for 90 years. A second specimen, collected from the same waters, is re-described. The presence of a single dorsal fin remains equivocal in so far as it represents the normal condition for the species. Aspects of the species' relationship with the species ofApristurus are discussed.  相似文献   

6.
Validity of the species Liparis schantarensis (Lindberg and Dulkeit, 1929) (Scorpaeniformes: Liparidae) is confirmed and redescribed based on six new specimens collected in Avacha Bay on the southeastern Kamchatka Peninsula. These specimens are the first records of this species reported in more than 70 years and the first outside the Sea of Okhotsk. Distinguished from almost all other members of the genus Liparis by a comblike anteriormost part of the dorsal fin, both males and females have 5–7 elongated anterior dorsal fin rays, with the distal ends free of the membrane for about one-half to two-thirds the length of the ray.  相似文献   

7.
Female preference for male fin elaborations in Poeciliid fishes may be driven by a sensory bias for increased lateral projection area (LPA) that has existed since the lineages diverged from a common ancestor. Previous research supports this hypothesis demonstrating female Poecilia latipinna, Poecilia mexicana, and Poecilia reticulata prefer males of larger body and dorsal fin size, but exhibit no such preferences when controlling for total LPA. In the current study, we further tested this hypothesis by presenting female platys, Xiphophorus variatus, with pairs of dummy males differing in: (1) body size (holding dorsal fin size constant); (2) dorsal fin size (holding body size constant); and (3) dorsal fin: body size ratio (holding total LPA constant). Females spent more time near dummies of greater body and dorsal fin size; however, in the third experiment, neither fin size, body size, nor any particular dorsal fin + body size combination was preferred. These results provide additional support for the LPA and sensory bias hypotheses, demonstrating that female X. variatus not only prefer males with “swords”, but sailfin-like dorsal fins as well when body size is held constant. Shared preference for increased LPA is consistent with common ancestry of the sensory/neural systems in females of all four species.  相似文献   

8.
The dermal layers of several elasmobranch species have been shown to be sexually dimorphic. Generally, when this occurs the females have thicker dermal layers compared to those of males. This sexual dimorphism has been suggested to occur as a response to male biting during mating. Although male biting as a copulatory behaviour in Scyliorhinus canicula has been widely speculated to occur, only relatively recently has this behaviour been observed. Male S. canicula use their mouths to bite the female’s pectoral and caudal fins as part of their pre-copulatory behaviour and to grasp females during copulation. Previous work has shown that female S. canicula have a thicker epidermis compared to that of males. The structure of the dermal denticles in females may also differ from that of males in order to protect against male biting or to provide a greater degree of friction in order to allow the male more purchase. This study reveals that the length, width and density of the dermal denticles of mature male and female S. canicula are sexually dimorphic across the integument in areas where males have been observed to bite and wrap themselves around females (pectoral fin, area posterior to the pectoral fin, caudal fin, and pelvic girdle). No significant differences in the dermal denticle dimensions were found in other body areas examined (head, dorsal skin and caudal peduncle). Sexually dimorphic dermal denticles in mature S. canicula could be a response to male biting/wrapping as part of the copulatory process.  相似文献   

9.
10.
《Geobios》1986,19(3):393-399
A new species of chimaeroid, Harriotta lehmani, is described. It differs from Recent species of Harriotta in the shape of the paired rostral cartilages and second dorsal fin. This is the first record of a chimaeroid from the Cretaceous fish-beds of Lebanon, as well as being the first fossil representative of the genus Harriotta.  相似文献   

11.
Richard Lund 《Geobios》1984,17(3):281-295
Several specimens of an elasmobranch from the upper Mississippian Bear Gulch limestone of Montana are described. The first dorsal spine and fin closely resemble Stethacanthus erectus and to a lesser extent Stethacanthus altonensis. The new genus and species Orestiacanthus fergusi is proposed for the specimens, and it is suggested that recent attempts to synonymize the species of Stethacanthus on the basis of spines are unjustified. The specimens also share the enlarged cranial denticles, general form of the palatoquadrate, cladodont teeth and pectoral fin with S. altonensis. They differ from S. altonensis in proportions of jaws, numbers of tooth families, numbers of prearticular basals and axial radials, morphology of the second dorsal fin, and in the presence of generalized squamation in some specimens (but not the female). The pelvic fins differ greatly in having a prominent metapterygium.  相似文献   

12.
13.
A new species of spinous loach, Cobitis shikokuensis, is described based on 297 specimens from Shikoku Island, Japan. The new species was formerly known as the Shikoku group of Cobitis takatsuensis. It can be distinguished from other species of Cobitis and closely related genera by a combination of the following characters: dorsal fin with 6 branched soft rays; anal fin with 5 branched soft rays; one brownish streak across eye from the tip of nose, no streak on cheek; a black spot smaller than eye diameter near the dorsal corner of the caudal fin base; 3–5 small brownish speckles on ventral side of caudal peduncle; high caudal peduncle with well-developed fleshy keels on dorsal and ventral side; a lamina circularis at base of dorsal part of pectoral fin absent; first branched soft ray of pectoral fin broad in males; pectoral soft rays widely branched from the approximate midpoint; last anal fin ray with 2 elements; interorbital width 11.2–17.1% of head length.  相似文献   

14.
Oxynotus japonicus sp. nov. is described on the basis of a specimen collected by a bottom trawl at depths between 225 m and 270 m in Suruga Bay, Japan. It differs from other species of the genus in having the following combination of characters: spines of 1st and 2nd dorsal fins sloping slightly backward; length from tip of 1st dorsal spine to apex of 1st dorsal fin 2.6 times vertical height from tip of spine to fin base; length from tip of 2nd dorsal spine to apex of 2nd dorsal fin 1.9 times vertical height from tip of spine to fin base; and 2nd dorsal base 1.3 in interspace between 1st and 2nd dorsal fins.  相似文献   

15.
16.
Echinogobius hayashii, a new genus and species of Gobiidae is described, based on 11 specimens from Japan and Australia. This genus is distinguishable from all other gobiid genera in having the following combination of characters: first spine of first dorsal fin hard and straight, about 1.5 times second spine in thickness; first spine of second dorsal fin hard, with similar thickness as first soft ray of second dorsal fin, supported by two normally-sized pterygiophores; snout convex; preopercular spine absent; predorsal scales absent; all scales cycloid. The species occurs between 1–20 m in clear water on clear sandy bottoms influenced by fast tidal currents. Based on our observations, it is not associated with an alpheid shrimp.  相似文献   

17.
Pseudophoxinus burduricus sp. n. is described from drainages of Salda and Burdur lakes, southwestern Turkey. It is distinguished from other Anatolian Pseudophoxinus by a combination of characters: lateral line incomplete, with 21–39 (commonly 26–37) perforated scales and 47–57+1-2 scales in lateral series; 10½–12½ scale rows between lateral line and dorsal fin origin, 3–4(5) scale rows between lateral line and the pelvic fin origin; dorsal fin commonly with 7½ branched rays; anal fin commonly with 6½ branched rays; 7–8(9) gill rakers on the first branchial arch; a faint and diffuse epidermal black stripe from eye to caudal fin base in alive and preserved individuals; mouth slightly subterminal, tip of mouth cleft on about level of lower margin of eye; snout rounded, its length greater than eye diameter. Comparison is given with all Pseudophoxinus species from western Anatolia.  相似文献   

18.
A new pearleye species of the alepisauroid family Scopelarchidae, Scopelarchoides neamticus sp. nov., is described herein based on two specimens from the Oligocene Lower Dysodilic Shales Formation, cropping out in the Pietricica Mountain, Romanian Eastern Carpathians. The new species described herein exhibits a unique combination of features (including head length about 25% of SL; coracoid remarkably expanded; both preorbital and postorbital lengths larger than orbit diameter; 50 or 51 vertebrae; dorsal fin with nine or ten rays; anal-fin with 28 rays; length of anal fin base about 30% of SL; preanal distance almost 60% of SL; pelvic fin insertion located just under the second dorsal fin ray; pectoral fins only slightly longer than pelvic fins; caudal fin with 19 principal rays plus 14 upper and 13 lower procurrent rays) that justifies its recognition as a new species of the genus Scopelarchoides. Both morphological and meristic features suggest a certain degree of similarity between S. neamticus sp. nov. and the extant species Scopelarchoides signifer. The fossils of the new Oligocene species described herein represent the oldest known skeletal record of Scopelarchidae.  相似文献   

19.
A new species of the Recent genus Enophrys, E. hoplites sp. nov., is described from the Miocene (Serravalian?Tortonian) Agnevo Formation of Sakhalin Island, Russia. This Miocene species differs from two Recent congeners in the greater number of anal fin rays (14 versus 9?13), the smaller head, less raised margins of the orbit, flatter upper contour of the head, longer anal fin base, short predorsal distance, higher first dorsal fin, and in the right angle (versus acute angle) between two upper preopercular spines. An archaic feature of the new species is the presence of two rays on the posterior pterygiophore of the anal fin, a character recorded only in the most primitive Recent members of the family. The occurrence of this new fossil species shows that extant subfamilies, tribes, and genera existed as a part of the family Cottidae as early as the Miocene time.  相似文献   

20.
The annual reproductive cycle of the dragonet,Repomucenus valenciennei, from Tokyo Bay, Japan, was studied by analysis of seasonal trends in gonadosomatic indices and histological observations of gonads. Sexual dimorphism in the growth of several body parts relative to standard length (SL) and changes in color pattern of the first dorsal fin with growth were also investigated. The spawning season lasted from spring (April [1991] or February [1992]) to autumn (October) with two spawning peaks, in spring and autumn. In spring, only one-year-old (age 1+) fish spawned, age 0+ females not spawning until autumn, at which time they had reached age 1+. Likewise, histological observations of males indicated that testes had reached full maturity by 80 mm SL (age 1+). The minimum mature size of females was estimated as 60 mm SL. In males 45–80 mm SL, the first spine of the first dorsal fin, last ray of the second dorsal fin, last ray of the anal fin, and caudal fin ray showed strongly positive allometry, indicating rapid growth of these structures relative to SL. Subsequently, their growth returned to an isometric pattern in males>80 mm SL. In females, on the other hand, the same body parts showed slightly positive allometry throughout their growth. The color pattern on the first dorsal fin also changed in males 45–80 mm SL.  相似文献   

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