Morphometry of the Stone Loach, Barbatula Barbatula: Do Mensural Characters Reflect the Species' Life History Thresholds?

Growth variability in 23 mensural characters was examined in 387 specimens of stone loach, Barbatula barbatula, from England. The standard length (SL) of the specimens ranged from 15.3 to 115.4 mm. We tested the hypothesis that body proportions change abruptly, rather than gradually, at certain intervals of ontogeny by fitting linear, quadratic and split linear curves to plots of each variable against SL. Based on patterns of allometric growth, two groups and two subgroups of mensural characters have been found. Three characters were best explained by a linear regression, indicating isometric growth. Eight characters were best explained by a quadratic curve, indicating gradual allometry. The remaining 12 characters were best explained by a split regression, indicating mainly isometric growth with abrupt allometry occurring at a specific SL (breakpoint). The first shift in morphometric values (a transformation of the head; breakpoints in three characters) occurred at 26-35 mm SL, the second (a change in fin shape and size as well as body form; breakpoints in six characters) at 36-47 mm SL. The coincidence of shifts in body morphology with those in microhabitat use (between the respective size classes) suggests that thresholds (though not as sudden as those between embryo and early larva steps) do occur during this interval of stone loach life history. We suggest that the larva period ends with the completion of the first shift in relative growth (i.e. not later than at 35 mm SL, depending on individual variability), and that the second shift in morphometric values reflects a threshold between the first and the second step of juvenile period. The importance of changes in external morphology decreased as the fish grew bigger and older.     

高原特有条鳅鱼类两新种在广西的发现及其动物地理学意义

描述了采自广西都安县红水河水系的条鳅亚科鱼类2个新种：丽纹云南鳅yhnnanilus pulcherrimussp．nov．在侧线长度、鳞片分布、鳍条数目、尾型、吻须长度等方面与侧纹云南鳅yunnanilus pleurotaenia(Regan,1904)最为相似,但新种独特的斑纹和上下唇的长乳突可明显与之区别,二者在一些度量特征上也有区别。黄体高原鳅Triplophysa flavicorpus sp．nov．与同分布于西江水系的南丹高原鳅T．nandanensis Lan et al．较为相似,并以下列特征组合与高原鳅属所有已知种相区别：背鳍分枝鳍条10根、臀鳍分枝鳍条6～7根、体被细鳞、侧线完全、具6条宽横斑和1条沿侧线的细纵纹、尾鳍深分又、尾鳍基具1半圆形黑斑、尾鳍上下叶各具2条黑色横斑、腹鳍末端后伸超过肛门、腋部具发达的肉质鳍瓣、上唇中央完全中断等。云南鳅属和高原鳅属均是高原特有类群,前者仅分布于云南东中部地区,后者则集中分布于青藏高原。两个新种的分布地均远离这两个属的分布中心,而且呈间断分布。通过各自相近种谱系关系分析,推测这种特殊的分布格局是通过隔域分化形成的。     

Annual reproductive cycle and sexual dimorphism in the dragonet,repomucenus valenciennei, in tokyo bay, japan

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.     

广西高原鳅属鱼类一穴居新种记述

2003年1月,在广西壮族自治区天峨县红水河水系地下河采集到一批盲鱼标本。经鉴定,为高原鳅属Triplophysa一未经发表的新种。新种天峨高原鳅Triplophysa tianeensis sp．nov．与个旧盲高原鳅T．gejiuensis、石林盲高原鳅T．shilinensis、阿庐高原鳅T．aluensis和南丹高原鳅T．nandanensis相似;本新种腹鳍末端不达肛门,尾鳍分枝鳍条16,可进一步与个旧盲高原鳅和石林盲高原鳅(腹鳍末端达到肛门,尾鳍分枝鳍条14-15)相区别;本新种背鳍起点位于体之中点、腹鳍起点之后,肛门紧靠臀鳍起点,可进一步与阿庐高原鳅(背鳍起点靠近吻端、位于腹鳍起点之前,肛门距臀鳍起点仍有一段距离)相区别。本新种与同分布于红水河水系的南丹高原鳅Triplophysa nandanensis Lan et al.较为相似;但二者区别明显：新种背鳍分枝鳍条7、胸鳍分枝鳍条9、腹鳍分枝鳍条6、背鳍外缘平截、背鳍起点位于腹鳍起点之后,后者背鳍分枝鳍条8、胸鳍分枝鳍条10～11、腹鳍分枝鳍条7、背鳍外缘凹入、背鳍起点位于腹鳍起点之前;此外,新种的穴居特征更为显著：眼极度退化、头长为眼径16．8—32．8(25．0)倍、部分个体无色素斑且各鳍无斑点,而南丹高原鳅眼小、头长为眼径4．7～9．0(7．5)倍、体和头背侧密布云状斑且各鳍均具点状斑。     

Larval and juvenile Polymetme elongata (Stomiiformes: Phosichthyidae) collected from Suruga Bay and offshore waters, Japan

Two larvae [17.4 mm standard length: SL (postflexion stage)] and 26.1 mm SL (transformation stage)] and a juvenile (31.7 mm SL) of a phosichthyid, Polymetme elongata, from Suruga Bay and offshore waters, central Japan, are described. These specimens had an elongate body with relatively short preanal length (53–63% SL), long anal fin base (2.6–3.4 times dorsal fin base length), and anal fin origin below dorsal fin base, and were further characterized by a blackish flap on each eye and internal clusters of melanophores (e.g., along caudal myosepta around midlateral line and on ventral margin of caudal peduncle). The short preanal length and larval melanophore pattern were very similar to those of another phosichthyid, Yarrella blackfordi, from the Atlantic Ocean.     

Ontogenetic patterns of relative growth in young roach Rutilus rutilus: within-river basin comparisons

To address the lack of information on the ecomorphology of young of the year juveniles (0+) freshwater fishes despite its importance to understanding geographical variation in life history, we compared the morphology of 0+ juvenile roach Rutilus rutilus from eight sub-regions of the River Great Ouse basin (U K) We tested for variation due to water retention structures, which could act to isolate upstream stocks from the general population Differences in mensural characters between the eight different regions appeared in ventral fin length and eye diameter only, which both were strongly affected by variable relative growth during early juvenile development, thus the discrepancies between regions were not due to geographical location Morphological development in roach ≥ 15 mm standard length (SL) consists of two different intervals during the first (∼ 15-40 mm SL). in contrast to adults, several mensural characters continue to develop allometrically. either positively or negatively suggesting a continuance of the larval period Whereas, m the second interval (> ∼40 mm SL). all the mensural characters except head length and eye diameter grew close to lsometrically with body length, and the rate of variation in relative growth became as strongly limited as that previously reported for adults In contrast to previous studies, which are based on few specimens we suggest this second interval to be the true start of the juvenile period     

Channa panaw, a new channid fish from the Irrawaddy and Sittang River basins, Myanmar

Channa panaw sp. nov. (Channidae) is described from 32 specimens collected from the Irrawaddy and Sittang River basins, Myanmar. It is distinguishable from all known congeners by the combination of the following characters: 32–35 dorsal fin rays, 23–24 anal fin rays, 17–20 pectoral fin rays, 39–41 lateral line scales, 39–41 total vertebrae, one large scale on each side of the lower jaw (rarely 2 on one side), pelvic fin length always more than 50% of pectoral fin length, and 7–12 irregular black blotches on the upper half of the body.     

中国广西金线鲃属一新种(鲤形目,鲤科,鲃亚科)

2001年5月作者于广西环江县驯乐乡顺宁村采集到金线鲃属盲鱼5尾,经鉴定为一新种.新种眼睛完全退化,头后急剧隆起但尚未形成额骨突等体型特征与无眼金线鲃Sinocyclocheilus anophthalmus Chen et Chu,1988相似,而明显有别于属内其他物种.但两者在以下性状上又存在明显区别:1)新种背鳍硬刺纤弱;而无眼金线鲃的背鳍硬刺比较粗壮;2)新种背部自额骨后隆起,但是额骨顶部并不隆起;无眼金线鲃则自眼眶上方的额骨顶部开始显著隆起,直至肩部;3)新种侧线平直;无眼金线鲃的侧线在腹鳍和臀鳍之间的上方有一比较明显的向上弯曲;4)新种胸鳍长,超过腹鳍起点;无眼金线鲃胸鳍不超过腹鳍起点;5)分布区亦有所不同,新种分布于柳江水系;无眼金线鲃则分布于南盘江水系.此外,在一些可测性状上二者亦有区别,在标准长与体高和头长的比例、尾柄长与尾柄高的比例、侧线鳞的数目等性状上都有所差异.     

<Emphasis Type="Italic">Amblyceps improcerum</Emphasis>, a new sisoroid catfish from Kachin State,Myanmar (Teleostei: Siluriformes: Amblycipitidae)

A new species of amblycipitid catfish is here described from the Indawgyi Lake basin of the Irrawaddy River drainage in Kachin State, Myanmar as Amblyceps improcerum, new species. It can be distinguished from congeners in having a unique combination of the following characters: lower jaw longer than upper; head length 17.4–22.3% SL; head width 13.7–15.2% SL; head depth 9.0–11.7% SL; interorbital distance 31–39% HL; eye diameter 7–10% HL; 37–38 vertebrae; lateral line incomplete; predorsal length 25.5–30.7% SL; smooth posterior margin of pectoral spine; pectoral-fin length 13.5–16.8% SL; pelvic-fin length 9.6–13.4% SL; dorsal-to-adipose distance 25.2–28.7% SL; length of adipose-fin base 19.4–23.3% SL; adipose fin separate from dorsal procurrent caudal-fin rays; preanal length 62.1–66.9% SL; body depth at anus 9.8–12.8% SL; depth of caudal peduncle 10.1–12.6% SL; length of caudal peduncle 21.4–24.0% SL, post-adipose distance 15.8–17.8% SL; weakly-forked caudal fin with short broadly, rounded lobes (length of longest ray 1.3–1.5 times length of median rays); centrally projecting hooks on proximal lepidotrichia of median caudal-fin rays absent.     

Osteological development in the Japanese sardine,Sardinops melanostictus

The development of all osteological elements, except scales, of the Japanese sardine,Sardinops melanostictus, is described from newly-hatched larvae to adult fishes. Newly-hatched larvae lacked osteological elements. Part of the head skeleton began to develop in 53 hour old larvae (4.2 mm in notochord length [NL]). Larvae at the first-feeding stage (77 hours, 5.5 mm NL) possessed several elements of the head skeleton and pectoral fin supports. In a 10.5 mm NL specimen, part of the caudal and dorsal fin supports were apparent. The centra appeared in specimens 18–22.7 mm in standard length (SL). Gill rakers were first observed in the lower branchial arches at 13 mm NL and spine-like processes with spiny nodules from about 25 mm SL. The distance between the predorsal and first dorsal proximal radial relative to SL rapidly decreased with forward translocation of the dorsal fin and became constant beyond approximately 34 mm SL. At this stage, most basic osteological elements were established. Completion of the osteological structure was characterized by the disappearance of the dentary teeth at 60–70 mm SL. Based on the osteological development, ontogenetic intervals consisting of four periods and eight phases were recognized.     

Sexual dimorphism in <Emphasis Type="Italic">Sebastes owstoni</Emphasis> (Scorpaenidae) from the Sea of Japan

Morphological and genetic differences between red and yellow morphotypes of Sebastes owstoni were investigated, utilizing 277 males [84.0–194.3 mm in standard length (SL)] and 542 females (92.3–251.5 mm SL) from the Sea of Japan. All males smaller than 120 mm SL were characterized by red body color. The frequency of specimens with yellow body color thereafter increased gradually with SL, all specimens larger than 170 mm SL being yellow. The specimens with yellow body color were observed throughout the year. All females smaller than 170 mm SL were characterized by red body color, the frequency of specimens with yellow body color tending to slightly increase with SL. However, most females had red body color, except for 16 specimens (177.7–241.5 mm SL) that were yellow, growth-related color change from red to yellow being uncommon. Morphological analysis of 49 males (107.6–193.3 mm SL) and 68 females (108.7–241.5 mm SL) showed the head length, orbit diameter, lower jaw length, and predorsal length to be relatively greater, but the distance between the pelvic and anal fins less, in males. A discriminant analysis using Mahalanobis distances resulted in 100% correct assignment of specimens to sex, regardless of SL and body color. In addition, no genetic differences were apparent between red and yellow individuals in mitochondrial DNA sequence analyses from the threonine tRNA to the first half of the control region (498 bp). Accordingly, the differences in body color, maximum size, and the five morphometric characters listed above were considered to represent sexual dimorphism. That evidenced by body color was considered to appear after that shown by morphometric characters, some exceptions in the former occurring in females. This is the first report of permanent sexual dimorphism in body color in Sebastes.     

Juvenile development of a flathead,Suggrundus meerdervoortii (Scorpaeniformes: Platycephalidae)

Juvenile development ofSuggrundus meerdervoortii was described, based on twelve specimens (12.9–43.8 mm SL) collected from off Yamagata Prefecture, Japan Sea. Two exterior openings in the lateral line scales were completed at ca. 35 mm SL, with the interopercular flap and iris lappet being visible at ca. 44 mm SL, these all being useful taxonomic characters. In juveniles and additional young and adult specimens (ca. 70–191 mm SL), the proportions of head length, snout length, orbital diameter, caudal peduncle depth and caudal fin length decreased with growth; interorbital width decreased rapidly until ca. 70 mm SL, but more or less stabilised thereafter (70–191 mm SL).     

Morphometric variation among river sturgeons (Scaphirhynchus spp.) of the Middle and Lower Mississippi River

Pallid sturgeon (Scaphirhynchus albus) captured in the Middle and Lower Mississippi River (i.e. below St. Louis, MO, USA) are morphologically very similar to shovelnose sturgeon (Scaphirhynchus platorynchus). Available empirical data are limited to a few studies based on low sample sizes from disjointed populations. Geneticists are currently searching for markers that will differentiate the two species, but the need for unequivocal species‐specific field characters remains. Continuation of commercial fishing for shovelnose sturgeon in some states necessitates an immediate means for accurate field identifications. Previous studies of lower basin river sturgeon classified individuals with simple morphometric character indices and interpreted intermediacy as interspecific hybridization. In this study, morphometric variation among Scaphirhynchus specimens from the Middle and Lower Mississippi River is examined for evidence of hybridization. Data are compared for large (>250‐mm standard length) hatchery‐reared and wild pallid specimens and wild shovelnose specimens. Specimens are compared using two morphometric character indices, two morphometric/meristic character indices and principal components analysis. Results indicate substantial morphological variation among pallid sturgeon below the mouth of the Missouri River. The amount of variation appears to decrease downstream in the Mississippi River. Sheared principal components analysis of morphometric data shows complete separation of shovelnose and pallid sturgeon specimens, whereas character indices indicate overlap. Both character indices and sheared principal components analysis demonstrate that pallid sturgeon in the Lower Mississippi River are morphologically more similar to shovelnose sturgeon than are pallids from the Upper Missouri River. This similarity, explained in previous studies as hybridization, may be the result of latitudinal morphometric variation and length‐at‐age differences between populations of the upper and lower extremes of the range.     

A new species,gerres infasciatus, from the gulf of thailand (perciformes: Gerreidae)

Gerres infasciatus sp. nov. is described from the holotype and two paratypes, 125–140 mm in standard length (SL), collected off Samut Prakan, northern Gulf of Thailand. The species is similar toG. filamentosus Cuvier andG. macracanthus Bleeker in general appearance, having an elongated second dorsal fin spine, but differs from them in having 39 or 40 pored lateral line scales, the first and second soft dorsal fin ray tips yellow in fresh specimens, a narrow, faint dusky-yellowish margin on the upper membrane of the spinous dorsal fin (between 4th–9th spines), the distal part of the pelvic fin (between 1st–5th soft rays) white for 1/3–1/2 of each ray length (lost after preservation), bands absent on the body in both fresh and preserved specimens, a smaller orbit diameter (11.4–12.4% of SL), a longer second dorsal fin spine (48.0–68.9% of SL), and shorter second and third anal fin spines (10.7–11.2% and 10.4–11.3% of SL), respectively.     

蛇鮈属一新亚种记述

蛇(鱼句)属为一群小型鲤科鱼类.蛇(鱼句)广泛分布于东亚大陆.通过对采自云南程海和珠江、闽江、长江、辽河、松花江等水系蛇标本的形态、度量特征进行仔细分析和比较,认为蛇程海种群是蛇的1个新亚种,命名为程海蛇(Saurogobio dabryi chenghaiensis).程海蛇(鱼句)的特征为:吻皮发达,盖过上唇;上下唇布满发达的乳突;体及尾柄极细长,体高为体长的12.7%～15.0%,尾柄高为体长的5.5%～6.1%、为尾柄长的31.8%～39.1%;沿体侧中轴自鳃孔上方至尾鳍基具一浅色暗纹,其上布有6～11个大型棒状黑斑(黑斑长为宽的2～4倍);肛门位于腹鳍长度的中点之后;尾鳍最长鳍条为其最短鳍条的2倍以上;仅分布于云南程海.     

A new pearleye (Teleostei,Aulopiformes) species from the Oligocene of Romania

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.     

北盘江光唇裂腹鱼年龄结构、生长特征和生活史类型

光唇裂腹鱼(Schizothorax lissolabiatus)主要分布于珠江水系南北盘江、元江、澜沧江和怒江等。以2008-2009年在北盘江采集的261尾光唇裂腹鱼为材料,研究了光唇裂腹鱼的年龄和生长特征。选用鳞片作为年龄鉴定的主要材料,并结合主鳃盖骨、匙骨、背鳍条等材料,对光唇裂腹鱼个体进行了年龄鉴定。结果表明:这4种材料年龄鉴定结果趋于一致,吻合性高。光唇裂腹鱼体长与鳞径的最佳函数关系为线性函数L=20.202R+65.726,体长与体重的最佳拟合方程呈幂函数关系W=4×10-5L2.8208。Von Bertalanffy方程、Logistic方程、Gompertz方程均为光唇裂腹鱼拟合性较好的生长方程,并以Von Bertalan-ffy方程的拟合度最高;光唇裂腹鱼Von Bertalanffy生长方程为:Lt=475.51[1-e-0.138(t+1.1397)],Wt=1424.93[1-e-0.138(t+1.1397)]2.8208;体重生长拐点为6.37龄。1~4龄为光唇裂腹鱼生长的快速阶段,而5龄以上个体的生长速度明显降低。根据r-选择和k-选择的典型特征以及渐近体长(L∞)、渐近体...     

Sexual dimorphism and developmental patterns in the external morphology of the vaquita,Phocoena sinus

A total of 56 vaquitas (Phocoena sinus) were examined to evaluate their sexual dimorphism and isometric and/or allometric growth in 35 external characteristics. Absolute and relative (to total length) measurements and growth rates were compared between sexually immature and mature females and males. T‐tests and analysis of variance (ANOVA) and covariance (ANCOVA) were used to evaluate sexual dimorphism. Sexual dimorphism in the vaquita was detected in the total length, head region (from blowhole to tip of upper jaw), anterior section of the body (from dorsal fin to tip of upper jaw), dorsal fin and the genital and anal regions. Fluke width is relatively larger in mature males than immature males, but in females this relative metric does not change during their development. In addition, males present a higher dorsal fin. These somatic changes are probably related to the swimming capacity (speed, agility, maneuvering) during the breeding season and/or foraging activities. A linear model of growth was used to determine possible proportional changes with respect to total body length through the development of 33 external characteristics. The anterior region of the body and the flippers were relatively larger in immature individuals than in mature ones.     

Plectranthias ryukyuensis,a new species of perchlet from the Ryukyu Islands,Japan, with a key to the Japanese species of Plectranthias (Serranidae: Anthiadinae)

A new perchlet, Plectranthias ryukyuensis, is described on the basis of four specimens (41.2–61.6 mm standard length: SL) from the Okinawa Islands, Japan. Plectranthias ryukyuensis can be distinguished from all congeners by the following combination of characters: X, 15 or 16 dorsal-fin rays; 14 pectoral-fin rays, all unbranched; lateral line complete, with 29 or 30 pored scales; 3 scale rows above lateral line; 5 or 6 diagonal rows of large scales on cheek between eye and corner of preopercle; preopercle with two antrorse spines on ventral margin, 20–29 serrae on posterior margin; margins of subopercle and interopercle with a few serrae (weak in large individuals); minute flaps at tips of first to ninth dorsal-fin spines; caudal fin shallowly emarginate, with some ray branches distinctively elongated past fin margin; fourth dorsal-fin spine longest, its length 110.6–128.6% that of third spine; body pinkish-white with two longitudinal rows of irregular orange-red blotches on upper half of lateral surface when fresh (rows close together in smaller than ca. 50 mm SL), blotches interconnecting anteriorly on upper and lower rows, and posterior half of lower row; four faint orange-red vertical bands below lateral line on posterior half of body and two distinct yellow blotches on cheek in fresh specimens; body uniformly yellowish-brown with two longitudinal rows of irregular dark blotches on upper half of lateral surface in preserved specimens (faint in small specimens). A key to the Japanese species of Plectranthias is given.