Anal Rays Research Articles

Meristic Characters of Two Morone Hybrids

Eight of 14 meristic characters counted for striped bass 9 (Morone saxatilis) x white bass d (M. chrysops) and striped bass 9 x white perch C (M. americana) hybrids showed statistical differences between the hybrid types. Of the eight, the clearest differentiating characters were: number of lateral line scales, number of scale rows above the lateral line, and number and appearance of tooth patches on the base of the tongue. Additionally, the dorsal fins were connected in the white perch hybrid. Both hybrids were generally intermediate between the parental species, but some traits resembled one parent more closely than the other. Frequency distributions for striped bass x white bass hybrid counts were skewed toward those characteristic of the white bass in four characters (second dorsal rays, pectoral rays, and scale rows above and below the lateral line) whereas counts of three characters (anal rays, tooth patches on the tongue and lateral line scales) were skewed toward those characteristic of the striped bass. Counts of five striped bass x white perch characters (pectoral rays, anal rays, scale rows above and below the lateral line, and tooth patches on the tongue) were skewed toward those characteristic of the striped bass, whereas counts of lateral line scales were skewed toward those of white perch. ,AND . 1972. Second discovery of mulDEPARTMENT OF BIOLOGY, SAMFORD UNIVERSItipl sex chro osomes among fishes. Experientia TY, BIRMINGHAM, ALABAMA 35209. Accepted

The influence of temperature change on number of anal fin rays developing in Fundulus majalis (Walbaum)

In each of two experiments embryos of this cyprinodont fish were reared continuously in four fluctuating temperature regimes, 13°–17°, 18°–22°, 23°–27°, and 28°–32°C to determine response of presumptive anal fin-ray tissue to temperature change. Because of excessive mortality among embryos in the 13°–17°C temperature regime, only one transfer lot from this regime could be used. In both experiments a positive linear relationship was indicated between mean anal fin-ray count and temperature, more anal rays developed on the average with increasing temperatures. In one experiment the transfer of embryos from one of the cooler regimes to the warmest at a three-to-six-somite stage of development produced a mean anal fin-ray count similar to that of embryos reared continuously in the warmest regime, but significantly different from the mean of those reared continuously in the original cool regime. The transfer of embryos from one of the cooler regimes to the warmest at a nine-to-twelve-somite stage produced a mean anal fin-ray count similar to that of embryos reared continuously in the cooler regime, but significantly different from the mean of those reared continuously in the warmest regime. In regard to morphological time of fixation of anal fin-ray tissue in this species temperature can influence the number of anal fin rays at the three-to-six-somite stage of development; although the nine-to-twelve-somite stage showed no response to temperature influence, later stages may be sensitive.

Larval Development of Rock Bass from the Susquehanna River

Abstract Eggs from the nest of a rock bass (Ambloplites rupestris) were collected by scuba divers in the Susquehanna River near Port Trevorton, Pennsylvania. At hatching, the mean total length (TL) and standard (notochord) length of three larvae were 5.6 and 5.5 mm, respectively. The newly hatched larvae were free of melanophores and had incomplete mouths, ovoid yolk sacs, straight urostyles, and pectoral fin buds. Melanophores began to appear in larvae by 6.8 mm TL. Caudal fin rays were visible by 6.9 mm; dorsal, anal, and pectoral fin rays by 8.6 mm; and pelvic fin rays by 13.5 mm. Rock bass larvae can be distinguished from Lepomis and Pomoxis by their larger size at hatching and larger body melanophores. Of the centrarchid larvae found in the Susquehanna River, rock bass can be easily confused only with smallmouth bass (Micropterus dolomieui); however, rock bass can be distinguished by the less dense arrangement of body melanophores, and by the larger numbers of preanal myomeres and anal spines.

Identification of Golden Shiner, Notemigonus crysoleucas, Spotfin Shiner, Notropis spilopterus, and Fathead Minnow, Pimephales promelas, Larvae

The various proportional length measurements and myomere counts for each larval phase of the cyprinid fishes golden shiner, Notemigonus crysoleucas, spotfin shiner, Notropis spilopterus, and fathead minnow, Pimephales promelas, are generally quite similar and typical of the family. Mean snout to vent lengths for protolarvae and mesolarvae ranged from 58 to 60% of total length and decreased to 54 to 59% for metalarvae. Mean total myomere counts for all phases overlapped among the species and ranged from 34 to 37.Identification of protolarvae and mesolarvae depends largely on melanophore distribution and patterns, while fin ray counts and position are applicable to metalarvae. Later protolarvae and mesolarvae of Notemigonus crysoleucas exhibit a distinctive midventral line of pigment anterior to the vent, while metalarvae are readily distinguished by an anal ray count of over 10 and pelvic fins well anterior to the dorsal fin origin. The later protolarvae, mesolarvae, and metalarvae of Notropis spilopterus are distinguished by a lack of melanophores on the ventral surface of the gill covers.These and other distinguishing features discussed are not necessarily unique to the cyprmids studied. Unless potentially similar species (undescribed or inadequately described) in a study area can be eliminated, identifications based on these characters should be considered tentative. Key words: Notemigonus crysoleucas, Notropis spilopterus, Pimephales promelas, Cyprinidae, fish, larvae, development, identification, taxonomy

Morphology of androgenetic and gynogenetic grass carp, Ctenopharyngodon idella (Valenciennes)

Crosses between female carp x male grass carp resulted in androgenetic grass carp and hybrids. Fertilizing grass carp eggs with carp milt that had been irradiated with ultraviolet light for 15 min at 1.0 mW/cm2 produced gynogenetic grass carp. We compared the morphology of experimental progeny with that of the parental species to determine if inheritance was strictly matroclinous in gynogenesis and strictly patroclinous in andro‐genesis. Dorsal and anal fin rays, lateral line scales, gill rakers, pharyngeal teeth, and the relative length of the dorsal fin all suggested that gynogenetic grass carp were identical with the maternal species and androgenetic grass carp with the paternal species. Hybrids were intermediate between the parents except that the number of anal rays was identical with that in carp. The number of dorsal rays, the body depth, and the pharyngeal teeth in hybrids were more like those in carp than in grass carp, whereas the number of gill rakers was more similar to that in the paternal species.

Temperature-induced meristic variation among three homozygous genotypes (clones) of the self-fertilizing fish Rivulus marmoratus

Embryos of clones DS, NA, and M were reared at sustained temperatures of 19, 25, and 31 °C. Diverse evidence indicates a closer genetic affinity between DS and NA than between either and M. DS and NA converged and M diverged regarding thermal responses of vertebrae, and anal and pelvic rays; DS and M converged and NA diverged regarding responses of pectoral, caudal, and dorsal rays. For vertebrae and pectoral rays, response curves were declivous; for caudal rays, inverted-V shaped; for anal rays, upright-V shaped (NA), inverted-V shaped (DS), declivous (M); for dorsal rays, declivous (NA), upright-V shaped (DS and M); for pelvic rays, subhorizontal (DS and NA), inverted-V shaped (M). The vertebral response curves of DS and NA diverged at 25 °C, converging at 19 and 31 °C. Caudal counts increased between 31 and 25 °C, caudal and precaudal, between 25 and 19 °C. Vertebral differences (as percentage of the midpoint count) exceeded any of previous experiments on species other than R. marmoratus. At 19 and 31 °C pelvic fins are often lacking, but never in outbreeding R. cylindraceus. Response curves except vertebral ones differed qualitatively between these species. Many kinds of variations, and proportions of phenotypic differences due to genotypic and environmental differences and their interactions are compared.

THE INTERRELATION BETWEEN VARIABILITY OF CHARACTERS, EFFECTIVENESS OF ENERGY UTILISATION, AND KARYOTYPE STRUCTURE IN FISHES.

EvolutionVolume 30, Issue 1 p. 180-185 ArticleFree Access THE INTERRELATION BETWEEN VARIABILITY OF CHARACTERS, EFFECTIVENESS OF ENERGY UTILISATION, AND KARYOTYPE STRUCTURE IN FISHES George Nikolsky, George Nikolsky Institute of Morphology and Ecology of Animals, Academy of Sciences of the USSRSearch for more papers by this author George Nikolsky, George Nikolsky Institute of Morphology and Ecology of Animals, Academy of Sciences of the USSRSearch for more papers by this author First published: March 1976 https://doi.org/10.1111/j.1558-5646.1976.tb00894.xCitations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume30, Issue1March 1976Pages 180-185 ReferencesRelatedInformation

Effects of temperature and sex genotype on meristic counts of the gonochoristic cyprinodontid fish Rivulus cylindraceus Poey.

Eggs were reared at sustained temperatures of 19 °C, 25 °C, and 31 °C, Thermal response curves were declivous (vertebrae), aclivous(caudal and anal fin rays),of inverted-V shape {pectoral and dorsal rays), and nondescript (pelvic rays). Thermally induced vertebral differences in Rivulus cylindraceus, as in previously studied gonochoristic fishes, were far smaller than in a homozygous clone (uniparental, isogenic line) of selfing, hermaphroditic R. marmoratus Poey. Mean counts of males were higher for all meristic trails at 19 °C and for vertebrae and rays of pectoral and caudal fins at all three temperatures, those of females were higher for dorsal, anal, and pelvic fins at 25 °C and 31 °C. Differences in means between sexes were significant statistically for pectoral and anal rays at 19 °C, pectoral rays at 25 °C, and dorsal rays at 31 °C. Among three genetically different homozygous clones of R. marmoratus, mean meristic counts were neither significantly different nor consistently higher between males and hermaphrodites. The switch mechanism determining 'sex type' (male versus hermaphrodite) in homogametic R. marmoratus is thermal, and meristic variability is thermally influenced. Meristic variability in heterogametic R. cylindraceus is also thermally influenced but the switch mechanism determining sex is chromosomal, with apparent side effects on meristic counts.

Heritable and temperature-induced meristic variation in the medaka, Oryzias latipes.

Eggs from 25 parental pairs were reared at sustained temperatures from 20C to 34C, or were changed from 20C to 30C or vice versa al various developmental stages. Crowding, mechanical shoes, container type, amount of aeration, and malachite green prophylaxis did not alter numbers of vertebrae, and pectoral or dorsal rays; nor did these numbers vary between eggs laid on different days by the same parents. Numbers of anal and caudal rays were significantly different between sibling egg batches, and were decreased by crowded rearing conditions. Mechanical shock increased anal ray counts. Caudal rays were sometimes decreased by lack of aeration. Response of vertebrae to different sustained temperatures was U-shaped in nine groups, with nadirs varying from 24C to 32C; in two groups, vertebrae were progressively fewer at higher temperatures. Pectoral ray counts usually were progressively lower at higher temperatures. Dorsal ray counts of most formed arched curves. In all series, heritable variation at one temperature roughly equalled phenotypic variability between temperatures. Inherited differences in response patterns of different meristic series are largely independent of each other, and of mortality and of hatching time. Temperature breaks produced an overcompensation in vertebrae if applied early, or a paradoxical reaction if applied late.

Meristic Variation in the Threespine Stickleback, Gasterosteus aculeatus, in the Matamek River System, Quebec

Samples of threespine sticklebacks, Gasterosteus aculeatus, from two lakes and a river in the Matamek River system, Québec were analyzed for five meristic characters. Mean vertebral number differed for each area (range 32.00–32.85) but mean soft fin ray number showed little variation (dorsal rays 11.52–11.79, anal rays 8.68–8.76). Gill raker number was higher in the lake samples (21.25 and 21.80) than in the river sample (20.76). In Matamek Lake only semiarmatus plate morphs were found; in Bill Lake, semiarmatus and trachurus morphs in a ratio of 4:1 with about 10% intermediate; and in the lower Matamek River, semiarmatus and, at a low frequency, leiurus morphs.

A New Species of Damselfish (Pisces: Pomacentridae) from the Eastern Coast of South America

Eupomacentrus rocasensis, a new pomacentrid fish, differs from its closest congener E. variabilis by its larger body size, slightly lower numbers of dorsal and anal rays, the distinctively large pectoral spot and caudal peduncle saddle, and the unique black line of pigment extending from pelvic base to anal fin and ringing the anus. E. rocasensis may have a geographical range limited to Atol das Rocas, near Brazil, South America. Adults were collected from tide pools indicating a shallow water habitat; thus transoceanic travel from Brazil to Atol das Rocas probably involved larvae and not adults.

Occella impi, a New Species of Sea Poacher from British Columbia with Notes on Related Species (Agonidae, Pisces)

Occella impi, a new species of sea poacher, is described from a single specimen captured in the Queen Charlotte Islands, British Columbia. Occella impi differs from other species of Occella in having spinous plates on the breast, the anus nearer the anal fin, and fewer anal rays; also, the numbers of bony body plates are distinctive. A key to the known species of Occella, based primarily on the numbers of bony body plates, is included. The size of the maxillary barbel and number of infralateral plates are shown to be characteristic of the genera Occella and Stellerina.

Two New Species of the Clingfish Genus Derilissus (Gobiesocidae) from the Western Atlantic

Description.-The body shape is shown in Fig. 1. Body proportions are as follows, with the corresponding proportional measurements in parentheses: head length 33.3-36.6%9 (2.7-3.0), head width 28.6-31.8% (3.1-3.4), body depth 27.1-36.6% (3.3-3.6), and pelvic disk length 23.9-25.2% (3.9-4.3) of standard length; eye length 21.6-23.6,% (4.2-4.6) of head length and 59.2-80.9% (1.2-1.6) of interorbital width; snout length 28.2-36.4% (2.73.5) of head length; caudal peduncle length 28.9-50.0% (2.0-3.4) of caudal peduncle least depth. The fin ray counts are as follows, with the frequency of each count in parentheses: dorsal 7(1), 8(2) with the first dorsal ray unsegmented and fused; anal 7(1), 8(1), 9(1) with two specimens having counts of 7 and 9 not having the first anal ray unsegmented and fused; pectoral (both sides counted) 28(2), 29(3), 30(1); pelvic I, 4(3); principal caudal rays 7 + 7(3). All fin rays in all fins are unbranched. In Fig. 1 the anal fin is shown with seven fin rays, however there is another ray hidden within the skin at the anterior end.

A new species of <i>Acestrocephalus</i> (Characiformes: Characidae) from Venezuela

A new species of Acestrocephalus is described from 60 specimens collected in the Río Orinoco and Río Negro drainages, Venezuela. This species is distinguished from all other Acestrocephalus by the combination of the following characters: anal rays, 29-36; 63-71 perforated scales on the lateral line; 10-12 scales above and 9-12 below the lateral line; 39-52 teeth on the maxillary; 9-12 premaxillary teeth; 8-12 teeth in the inner row on the dentary; 5-7 gill rakers on the lower part of the first gill arch; humeral, peduncular and caudal blotch absent.

Genetic Analysis of Soluble Lens Protein Polymorphism in Brook Trout, Salvelinus fontinalis

7b. Dorsal rays 9-11; anal rays 8-9; disc length 5.1-5.7 in standard length. 8a. Anus much closer to origin of anal fin than to rear margin of disc; disc length 5.7 in standard length; 8 sharp rakers on second gill arch __ lineatus Briggs 8b. Anus about halfway between origin of anal fin and rear margin of disc; disc length 5.1-5.3 in standard length; 5 shallow rakers on second gill arch minor Briggs 7b. Dorsal r ys 9-11; anal rays 8-9; disc length 5.1-5.7 in standard length. 8a. Anu much c oser to o gin of anal fin than to rear margin of disc; disc length 5.7 in standar ength; 8 sharp rakers on second gill arch _ lineatus Briggs 8b. Anus a out halfway between origin of anal fin and rear margin of dis ; disc length 5.1-5.3 in standard length; 5 shallow rakers on sec-

Variation in Selected Meristic Characters of Some Basses, Micropterus

Roentgenograms of 678 individuals of the genus Micropterus are examined. Mean numbers of anal rays are generally greater and the mean numbers of vertebrae are less in M. punctulatus from upstream localities compared to downstream stations on the Ohio River. Some M. punctulatus have as few as 30 vertebrae; the previous low recorded for this character in the genus is 31. The subspecies M. s. salmoides and M. s. floridanus may be distinguished on the basis of their respective ratios of abdominal to caudal vertebrae.

A New Clingfish (Gobiesocidae) of the Genus Tomicodon from Ecuador

Diagnosis.-A medium-size Tomicodon with 7(5-8) pairs of trifid incisors in upper jaw and 5 (4-6) pairs in the lower jaw. Anus markedly closer to anal fin origin than to rear margin of disc. The margin of anterior nostril has no dermal flap. Dorsal rays 10, anal rays 8 (7-9), pectoral rays 20 (19-21), and caudal rays 11 (10-12). Description.-Anterior portion of body only slightly depressed, depth 6.1 (5.5-6.6) in standard length. Caudal peduncle relatively short, least depth 1.3 (1.3-1.4) in its length. Head depressed, length 3.0 (2.8-3.3) and width 4.6 (4.3-5.0) in standard length. Snout moderately shallow with a rounded outline, 3.5 (3.2-3.7) in head; posterior nostril in front of anterior edge of eye. Teeth at front of upper jaw trifid incisors; these followed on each side by 2 (1-3) very small canines. Teeth at front of lower jaw also trifid incisors; these followed on either side by 2 (1-3) small canines. Six short, blunt rakers on posterior margin of each of the last two gill arches. Greatest diameter of eye 0.6 (0.5-0.7) in bony interorbital space and 3.6 (3.33.9) in 75

Variation and taxonomic changes in the family Retropinnidae (Salmonoidea)

Summary The family Retropinnidae contains one monotypic genus, Stokellia, in New Zealand, and nine nominal species of Retropinna: five in New Zealand, three in Australia, and one on Chatham Island. Four Chatham Island populations contain much of the recorded range of variation for the family for head length in standard length ratios, numbers of dorsal and anal rays, and numbers of scale rows. These characters are analysed for 29 populations incorporating five nominal species from New Zealand and Chatham Island. When interrelated these characters are shown to be linked (loosely) and high values are typical of coastal populations. When related to latitude their values increase to the south. The reverse trend is found with increase in altitude. Decrease in salinity depresses the values. Area of the lake habitat has little effect. Observations suggest that size of fish and numbers of teeth vary predictably. Thus all observed variation is related to environmental conditions. The four nominal lake species are s...

On the heredity of Y-linked color genes in Xiphophorus pygmaeus nigrensis Rosen (Pisces)

The inheritance of two Y-linked colour genes of the Poecillid Xiphophorus pygmaeus nigrensis has been described. Males with the gene Fl (=flavus) posess a yellow colouration of the body whereas those with the gene Vfl (= venter flavus) only at the basis of the anal ray. These patterns depend on G-xanthophores, yellow pigment cells with colourless granulation (Oktay).

Distribution and Synonymy in the Pacific Ocean, and Variation, of the Greenland Halibut, Reinhardtius hippoglossoides (Walbaum)

Long known in the Pacific Ocean from a single specimen from east-central Japan, the very distinctive flatfish genus Reinhardtius has been shown since 1930 to maintain a population of commercial significance from northern Japan to northwestern Bering Sea. It is now found to be common also in eastern Bering Sea, and to occur also just south of the tip of the Alaska Peninsula, in northern and central California, and even at the extreme north of Baja California, Mexico. Japan and the Californias appear to be inhabited by non-breeding expatriates, whose wanderings are attributable to the free-swimming habits and prolonged early pelagic development of the species. Lack of records between the Alaska Peninsula and California may possibly indicate actual absence, attributable to current pattern. Analysis of the only morphometric characters thought to be indicative of subspecific differentiation between the Pacific and Atlantic stocks discloses no basis for such separation, nor do any meristic characters disclose such a basis. The single species Reinhardtius hippoglossoides is therefore regarded as a uniquely undifferentiated amphiboreal taxon. The chief distinction between the ocean stocks lies in the number of vertebrae, but the differentiation (probably genetic) is not beyond the racial level. The difference in vertebral numbers, surprisingly, is not paralleled by a difference in numbers of dorsal or anal rays; nor is there any marked correlation between vertebral and ray numbers. As expected, the numbers of dorsal and anal rays are found to be positively correlated, and the number of precaudal and caudal vertebrae to be negatively correlated. In this flatfish of relatively limited asymmetry the numbers of rays are virtually identical in the two pectoral fins. Two reversed examples of the species are reported.