Homatula laxiclathra (Teleostei: Balitoridae), a new species of nemacheiline loach from the Yellow River drainage in Shaanxi Province, northern china

Homatula laxiclathra, new species, is here described from the Wei-He of the Yellow River drainage in Shaanxi Province, northern China. It is similar to H. berezowskii, H. longidorsalis, and H. variegata in the shared possession of a shallower body with a uniform depth, a character distinguishing all of them from all other congeners, but differs from these three species in the width of vertical brown bars on the caudal peduncle. This new species, along with H. berezowskii, differs from H. longidorsalis, and H. variegata in head length, caudal-peduncle depth, length of the dorsal adipose creast of the caudal peduncle, body squamation, and intestinal coiling. Homatula laxiclathra and H. berezowskii are further distinct in the caudal-fin shape and interorbital width.     

Deconstructing an octogenarian misconception reveals the true Corydoras arcuatus Elwin 1938 (Siluriformes: Callichthyidae) and a new Corydoras species from the Amazon basin

After 80 years of misidentifications, the analysis of the holotype of Corydoras arcuatus plus several non-type specimens attributed to this species allowed its recognition and also revealed a new species, both sharing the following diagnostic features: a long, arched, continuous black stripe that runs parallel to the dorsal profile of the body and extends at least from the anterior margin of the first dorsolateral body plate to the posterior portion of caudal peduncle; absence of transverse black bars on caudal fin; infraorbital 2 in contact with sphenotic and compound pterotic. In addition to these features, C. arcuatus can be distinguished from congeners by having the posterior margin of both dorsal and pectoral spines with laminar serrations directed towards their origins. The new species can be additionally distinguished from its congeners by presenting the following combination of features: ventral surface of trunk entirely or partially covered by relatively large and coalescent platelets; absence of spots or blotches on dorsal fin; and posterior margin of both dorsal and pectoral spines with serrations directed towards their tips. Finally, an identification key to all arc-striped species of Corydoras is provided.     

Relationship between shape and trophic ecology of selected species of Sparids of the Caprolace coastal lagoon (Central Tyrrhenian sea)

Synopsis The shapes of juveniles of nine species of the family Sparidae (Diplodus annularis, Diplodus puntazzo, Diplodus sargus, Diplodus vulgaris, Lithognathus mormyrus, Pagellus acarne, Sarpa salpa, Sparus aurata, Spondyliosoma cantharus), collected in the tide channel of the Caprolace Lagoon (Central Tyrrhenian Sea—Italy) were studied using geometric morphometry. These species have different ecologies. The trophic ecology of each species, reported as TROPH values, are related to shape. For the first time the relationship between shape and trophic ecology in sparids was studied in a quantitative way giving an ecomorphological meaning to the shape differences. Mean shapes of carnivorous, omnivorous and herbivorous fish were extracted, analyzed and found to be unique. Strict herbivores such as Sarpa salpa have a small mouth gap; omnivores such as the four species of the genus Diplodus have a higher body (discoidal) and a caudal peduncle shorter and higher; carnivorous species such as Lithognathus mormyrus, possess a relatively larger head region, a larger mouth gap, a longer body and a caudal peduncle longer and narrower.     

A Morphospace for Reef Fishes: Elongation Is the Dominant Axis of Body Shape Evolution

Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation) and the main vector of shape variation (first principal component) for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae), the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae). In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of developmental processes and functional consequences.     

Habitat-specific morphological variation among threespine sticklebacks (Gasterosteus aculeatus) within a drainage basin

Habitat-specific morphological variation, often corresponding to resource specialization, is well documented in freshwater fishes. In this study we used landmark based morphometric analyses to investigate morphological variation among threespine sticklebacks (Gasterosteus aculeatus L.) from four interconnected habitat types within a single lowland drainage basin in eastern England. These included the upper and lower reaches of the river, the estuary, a connected ditch network and a coastal salt marsh. We found significant habitat-specific differences in morphology, with three axes of variation describing differences in orbit diameter, body depth, caudal peduncle shape and pectoral fin positioning as well as variation in relative dorsal and pelvic spine size. Interestingly, the ditch system, an artificial and heavily managed habitat, is populated by sticklebacks with a characteristic morphology, suggesting that human management of habitats can in some circumstances lead to morphological variation among the animals that inhabit them. We discuss the mechanisms that conceivably underlie the observed morphological variation and the further work necessary to identify them. Finally, we consider the implications of habitat-specific body shape variation for the behavioural ecology of this ecologically generalist species.     

A new species of rainfrog of the Eleutherodactylus milesi species group (Anura: Leptodactylidae) from Guatemala

A new rainfrog of the Eleutherodactylus milesi group is described from the Sierra de Xucaneb, Guatemala. It is compared to the other 11 upland species from southern Mexico, Guatemala and Honduras referred to the group. Within the milesi group the new species differs from the other five forms which also have toe fringes in size of the finger disks, the snout shape in profile and the amount of toe webbing and dorsal tuberculation. Difficulties in distinguishing among the character states for the tympanum (distinct, indistinct and hidden) and between toe ridges and fringes indicate that very subtle differences separate recognized species.     

Morphological variation in vanishing Mexican desert fishes of the genus Characodon (Goodeidae)

This study investigated a rapidly vanishing group of fishes in the genus Characodon (including Characodon lateralis and Characodon audax) from the upper Rio Mezquital drainage in Mexico. Using specimens from museum collections, morphological variation was assessed to quantify body shape differentiation among historic (i.e. extirpated and extant) collection sites. In both sexes, body shape (particularly head shape, the proportion of the caudal peduncle and the position and size of dorsal and anal fins) varied significantly among populations and species. Variation among collection sites could at least partially be attributed to geography, as the presence of distinct hydrographic units and a major waterfall coincided with major body shape differences. These results are discussed in the light of previously published molecular genetic analyses, as they have direct implications for taxonomic problems and the need for conservation measures for these endangered fishes.     

中国NFDA2亚科金线NFDA2属鱼类一新种及其生态和适应(鲤形目：鲤科)

1999年11月在广西都安县下坳乡一岩洞地下水中采到1尾鱼类标本,经鉴定为金线NFDA2属一新种。新种与大鳞金线NFDA2S. macrolepis和陆良金线NFDA2S. macroscalus相近。但新种在背腹鳍相对位置以及背鳍末根不分枝鳍条后缘具锯齿等方面与上述两种存在明显差异;特别是该新种仅局限分布于洞穴中,就其生境来说也与上述两种更为不同。此外,新种头长与吻长和头长与眼径的比例是目前该属内已知最小的,眼明显偏大,反映出其对弱光生境条件的适应。     

A new squalid species of the genusCentroscyllium from the emperor seamount chain

A new etmopterine species,Centroscyllium excelsum, is described from 21 adult specimens captured in the Emperor Seamount Chain, central North Pacific. The present species is distinguished from its congeners in having a very high and semicircular-shaped 1st dorsal fin with a developed spine, dermal denticles only on dorsal side of head and trunk, the 2nd dorsal spine arising behind pelvic fin base, a short caudal peduncle, and prefrontal wall and chondrified eye stalk on neurocranium. Ten embryos were collected from one of the female specimens, and some embryonic features are also noted.     

Morphological divergence of lake and stream Phoxinus of Northern Italy and the Danube basin based on geometric morphometric analysis

Minnows of the genus Phoxinus are promising candidates to investigate adaptive divergence, as they inhabit both still and running waters of a variety of altitudes and climatic zones in Europe. We used landmark‐based geometric morphometric methods to quantify the level of morphological variability in Phoxinus populations from streams and lakes of Northern Italy and the Danube basin. We analyzed body shape differences of populations in the dorsal, lateral, and ventral planes, using a large array of landmarks and semilandmarks. As the species identification of Phoxinus on morphological characters is ambiguous, we used two mitochondrial genes to determine the genetic background of the samples and to ensure we are comparing homogenous groups. We have found significant body shape differences between habitats: Minnow populations inhabiting streams had a deeper body and caudal peduncle and more laterally inserted pectoral fins than minnows inhabiting lakes. We have also found significant body shape differences between genetic groups: Italian minnows had deeper bodies, deeper and shorter caudal peduncles, and a shorter and wider gape than both groups from the Danube. Our results show that the morphology of Phoxinus is highly influenced by habitat and that body shape variation between habitats was within the same range as between genetic groups. These morphological differences are possibly linked to different modes of swimming and foraging in the respective habitats and are likely results of phenotypic plasticity. However, differences in shape and interlandmark distances between the groups suggest that some (though few) morphometric characters might be useful for separating Phoxinus species.     

New species of Ilyodon (Cyprinodontiformes: Goodeidae) from de Balsas river basin, Mexico

A new species of the fish genus Ilyodon is described from San Juan Tacámbaro river, Michoacán, México 19 degrees 10' 42" N, 101 degrees 20' 45" W. We used 129 specimens representing I. whitei, 60 of I. furcidens and 84 of the new species for our analyses. These included samples of both sexes. The new species is distinguished from I. whitei and I. furcidens by its strongly convex cephalic profile, the size and disposition of the pores of the lateral line of the preorbital, the thinner caudal peduncle, its strongly bifid tooth and the form and size of neural prezygapophyses of caudal vertebrae.     

The role of predation in variation in body shape in guppies Poecilia reticulata: a comparison of field and common garden phenotypes

The body shapes of both wild-caught and laboratory-reared male and female Trinidadian guppies Poecilia reticulata from two low-predation and two high-predation populations were studied, but predation regime did not seem to be the most important factor affecting body shape. Instead, complicated patterns of plasticity in body shape among populations and the sexes were found. In particular, populations differed in the depth of the caudal peduncle, which is the muscular region just anterior to the tail fin rays and from which most swimming power is generated. Strikingly, the direction of population differences in caudal peduncle depth observed in wild-caught individuals was reversed when P. reticulata were raised in a common laboratory environment.     

眼斑双锯鱼仔稚鱼发育异速生长

运用生态学和传统理论生物学的研究方法, 对孵化后眼斑双锯(Amphiprion ocellaris)仔、稚鱼在早期生存和环境适应上的异速生长及器官优先发育生态学意义进行了研究, 以期为眼斑双锯鱼人工繁殖和育苗提供参考资料。以11日龄为眼斑双锯鱼仔、稚鱼的区分时期, 结果表明, 眼斑双锯鱼仔、稚鱼的感觉、摄食和游泳等器官快速分化, 均存在异速生长现象。在头部器官中, 吻长、眼间距、口宽和头高在仔鱼期均为正异速生长, 吻至鳃裂前缘长和眼径为负异速生长。在身体各部位中, 仔鱼期体高、躯干长、尾长、尾柄长、尾柄高和体厚均为正异速生长, 仅头长为负异速生长; 在游泳器官中, 仔鱼期眼斑双锯鱼尾鳍、背鳍、胸鳍、腹鳍和臀鳍均为正异速生长。稚鱼期眼斑双锯鱼头部、躯干及游泳等各器官均为负异速生长。眼斑双锯鱼这些关键器官的异速发育, 对适应环境因子变化具有重要的生态学意义。     

A new miniature species of the genus Triplophysa (Balitoridae: Nemacheilinae) from Yunnan, China

During a re-examination of museum specimens of Triplophysa species, some specimens that had been collected from the Jialonghe River in Yunnan Province, China, in April 1975, were identified as a new species. Triplophysa parvus n. sp. can be distinguished by the following combination of characters: dorsal fin rays 3, ; anal fin rays 3, ; pectoral fin rays 1, 11; scales absent; two saddle-like blotches with fuzzy borders cranial to the dorsal fin and four saddle-like blotches caudal to the dorsal fin; distal margin of the dorsal fin emarginate; pelvic fin reaching caudally almost to the anus; anus located immediately cranial to the origin of the anal fin; caudal fin forked; caudal chamber of air bladder reduced to a small free protuberance; head slightly laterally compressed, head deeper than wide at nape; length of caudal peduncle being 18.0–20.0% of standard length; depth of caudal peduncle being 7.8–8.4% of standard length; eye diameter 17.6–21.4% of head length; body depth being 60.7–70.2% of head length; caudal peduncle depth being 39.1–45.0% of caudal peduncle length; and body width at the base of caudal peduncle 59.0–68.0% of the body depth at the base of caudal peduncle. These characters allow a distinction from the similar species of T. nasobarbatula, T. nandanensis, and T. macromaculata.     

Shared and unique features of morphological differentiation between predator regimes in Gambusia caymanensis

When multiple groups of organisms experience similar environmental gradients, their patterns of differentiation might exhibit both shared and unique features. Here, we investigated the relative importance of three factors in generating body shape variation in a livebearing fish, Gambusia caymanensis, inhabiting the Cayman Islands: (i) shared patterns of divergent selection between predator regimes (presence/absence of piscivorous fish) driving replicated morphological differentiation, (ii) historical island effects yielding different morphologies across the three islands and (iii) unique effects of predation on morphological differentiation within each island. Shared effects of predation proved much more important than historical or unique effects. Populations coexisting with piscivorous fish exhibited larger caudal regions and smaller heads than conspecifics found in the absence of predatory fish. These results match a priori predictions, and mirror recent findings in a number of fish species, suggesting predation might often drive predictable morphological trends in disparate fishes. However, interestingly, the sexes achieved this morphological pattern through different means: head depth, caudal peduncle length and depth in males; head length, caudal peduncle depth in females. In G. caymanensis, we quantitatively confirmed that predation intensity represents a primary driver of body shape differentiation.     

A New Lanternshark <Emphasis Type="Italic">Etmopterus splendidus</Emphasis> from the East China Sea and Java Sea

A new species of the lanternshark Etmopterus splendidus is described. This new species is distinguished from the congeners by the combination of the following characters: distance from snout tip to 1st dorsal spine much less than distance from the spine to upper caudal origin; caudal fin short, much less than head length; dermal denticles on lateral side of trunk with very small, erect thornlike, conical crowns, those on trunk arranged in regular longitudinal rows, and distinctly arranged on interdorsal area and on lateral trunk of interspace between 2nd dorsal and caudal, but not arranged in regular longitudinal rows on dorsal surface of interorbital and o abdomen; color in life purplish-black above and with inconspicuous bluish-black flank marks and three other bluish-black marks at base of caudal fin and along its axis; shape of flank marks narrow anterior to, but broader posterior to pelvic fins.     

四川省条鳅亚科鱼类的研究——Ⅰ.副鳅、条鳅和山鳅属鱼类的整理(鲤形目:鳅科)

本文为四川省条鳅亚科鱼类分类研究的第一部分,对分布于四川省的副鳅属(Paracobitis)、条鳅属(Nemacheilus)和山鳅属(Oreias)鱼类进行了比较系统的整理,这3个属分布在四川共有5种和亚种,其中乌江副鳅(Paracobitis wujiangensis sp.nov.)为新种。     

Heritability of morphology in brook trout with variable life histories

Distinct morphological variation is often associated with variation in life histories within and among populations of both plants and animals. In this study, we examined the heritability of morphology in three hatchery strains of brook trout (Salvelinus fontinalis), which were historically or are currently used for stocking and supplementation of both migratory and resident ecotypes in the upper Great Lakes region. In a common garden experiment, significant variation in body morphology was observed within and across populations sampled at three time periods. The most notable differences among strains were differences in dorso-ventral body depth and the shape of the caudal peduncle, with some differences in the anterior-posterior placement of the dorsal and ventral fins. Variation with and among 70 half-sib families indicates that heritabilities of morphology and body size were significant at most developmental time points both within and across strains. Heritabilities for morphological characters within strains ranged from 0 to 0.95 across time points. Significant within-strain heritabilities for length ranged from 0 to 0.93 across time points and for weight ranged from 0 to 0.88. Significant additive genetic variation exists within and across hatchery brook trout strains for morphology and size, indicating that these traits are capable of responding to natural or artificial selection.     

乐山棒花鱼形态特征的两性异形和雌性个体生育力

测定了乐山棒花鱼(Abbottina kiatingensis)繁殖期形态特征包括体长、头长、头宽、头高、吻长、眼后头长、眼径、眼间距、体高、尾柄长、尾柄高、尾鳍长、背鳍基前距、背鳍基长、腹鳍基前距、腹臀间距、体重和去内脏体重的两性异形和雌性个体生育力。繁殖期雄性个体的数量显著多于雌性个体,雌雄两性个体的体长差异不显著。特定体长的雌性个体的头长、头宽、头高、吻长、眼后头长、尾柄高、背鳍基前距、背鳍基长和去内脏体重显著小于雄性个体,其余指标不存在明显的差异。回归分析表明,乐山棒花鱼的怀卵数量与体长和体重回归关系显著,雌性通过个体大小(体长和体重)的增加来提高个体生育力。     

Description of two new species of Hisonotus Eigenmann & Eigenmann, 1889 (Ostariophysi,Loricariidae) from the rio Paraná-Paraguay basin,Brazil

Two new species of Hisonotus are described from the rio Paraná-Paraguay basin in Brazil. The most remarkable features of the new species are the odontodes forming longitudinally aligned rows (one odontode after the other, but not necessarily forming parallel series) on the head and trunk (vs. odontodes not forming longitudinally aligned rows), a pair of rostral plates at the tip of the snout (vs. a single rostral plate), the functional v-shaped spinelet (vs. spinelet non-functional, square-shaped, or absent). These features suggest close phylogenetic relationships with Hisonotus bockmanni, H. insperatus, H. luteofrenatus and H. piracanjuba. Additionally, both new species are distinguished from their congeners by characters related to head length and depth, orbital diameter, suborbital depth, caudal peduncle depth, pectoral-fin spine length, snout length and counts of teeth. Hisonotus paresi sp. n. further differs from its congeners by having contrasting dark geometric spots on the anterodorsal region of the body, a character lacking in H. oliveirai sp. n. The variation in number and shape of the rostral plate, posterior rostrum plates, infraorbitals and the preopercle in both new species and in H. insperatus are discussed.