Total Number Of Vertebrae Research Articles

Hox genes control vertebrate body elongation by collinear Wnt repression.

In vertebrates, the total number of vertebrae is precisely defined. Vertebrae derive from embryonic somites that are continuously produced posteriorly from the presomitic mesoderm (PSM) during body formation. We show that in the chicken embryo, activation of posterior Hox genes (paralogs 9-13) in the tail-bud correlates with the slowing down of axis elongation. Our data indicate that a subset of progressively more posterior Hox genes, which are collinearly activated in vertebral precursors, repress Wnt activity with increasing strength. This leads to a graded repression of the Brachyury/T transcription factor, reducing mesoderm ingression and slowing down the elongation process. Due to the continuation of somite formation, this mechanism leads to the progressive reduction of PSM size. This ultimately brings the retinoic acid (RA)-producing segmented region in close vicinity to the tail bud, potentially accounting for the termination of segmentation and axis elongation.

Delayed consequences of extremely low frequency magnetic fields and the influence of adverse environmental conditions on roach Rutilus rutilus L. embryos

Event Abstract Back to Event Delayed consequences of extremely low frequency magnetic fields and the influence of adverse environmental conditions on roach Rutilus rutilus L. embryos Viacheslav V. Krylov1*, Yulia V. Chebotareva1 and Yuri G. Izyumov1 1 I.D. Papanin Institute for biology of inland waters Russian Academy of Sciences, Russia It is widely known that animals are most sensitive to the influence of different environmental stressors, including magnetic fields, during the embryonic period. Our study presents data collected over a six-year period on the effects of extremely low frequency magnetic fields (MFs) (1.4-1.6 µT, 500 Hz and 1.4-1.6 µT, 72.5 Hz) and MFs in combination with other environmental stressors (elevated temperature, 0.01 mg/L water solution of trichlorfon, 0.01 mg/L water solution of copper sulphate penta-hydrate) on roach embryos. The effects of these stressors were studied during different stages of early development. The fish developed in ponds for four months after exposure to MFs. The weight, standard length and morphological characteristics of underyearlings which developed from the exposed embryos were recorded. An increase in embryo mortality and a decrease in size-weight indices in underyearlings were noted after fish had been exposed to a combination of magnetic fields and different adverse environmental factors. In addition, exposure to magnetic fields led to changes in the total number of vertebrae and in the number of seismosensory system openings in the mandibular bones of underyearlings. Magnetic fields of different frequency caused both increases (500 Hz) and decreases (72.5 Hz) in underyearlings' morphological diversity. The stressors used did not increase the fluctuating asymmetry of bilateral morphological characters. The possible microevolutionary effects of exposure to magnetic fields alone and in combination with other adverse environmental factors upon natural fish populations are discussed. Acknowledgements This study was supported by grant from the Russian Foundation for Basic Research (Project #14-04-31170-mol_a). Keywords: Rutilus rutilus, embryos, morphology, Elevated temperature, Trichlorfon, Copper, magnetic field Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Physiology, Behavior and Toxicology Citation: Krylov VV, Chebotareva YV and Izyumov YG (2015). Delayed consequences of extremely low frequency magnetic fields and the influence of adverse environmental conditions on roach Rutilus rutilus L. embryos. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00038 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Nov 2015; Published Online: 05 Nov 2015. * Correspondence: Dr. Viacheslav V Krylov, I.D. Papanin Institute for biology of inland waters Russian Academy of Sciences, Borok, Russia, krylovviacheslav@mail.ru Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Viacheslav V Krylov Yulia V Chebotareva Yuri G Izyumov Google Viacheslav V Krylov Yulia V Chebotareva Yuri G Izyumov Google Scholar Viacheslav V Krylov Yulia V Chebotareva Yuri G Izyumov PubMed Viacheslav V Krylov Yulia V Chebotareva Yuri G Izyumov Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Vertebral Formula in Red-Crowned Crane (<i>Grus japonensis</i>) and Hooded Crane (<i>Grus monacha</i>)

ABSTRACTRed-crowned cranes (Grus japonensis) are distributed separately in the east Eurasian Continent (continental population) and in Hokkaido, Japan (island population). The island population is sedentary in eastern Hokkaido and has increased from a very small number of cranes to over 1,300, thus giving rise to the problem of poor genetic diversity. While, Hooded cranes (Grus monacha), which migrate from the east Eurasian Continent and winter mainly in Izumi, Kagoshima Prefecture, Japan, are about eight-time larger than the island population of Red-crowned cranes. We collected whole bodies of these two species, found dead or moribund in eastern Hokkaido and in Izumi, and observed skeletons with focus on vertebral formula. Numbers of cervical vertebrae (Cs), thoracic vertebrae (Ts), vertebrae composing the synsacrum (Sa) and free coccygeal vertebrae (free Cos) in 22 Red-crowned cranes were 17 or 18, 9–11, 13 or 14 and 7 or 8, respectively. Total number of vertebrae was 47, 48 or 49, and the vertebral formula was divided into three types including 9 sub-types. Numbers of Cs, Ts, vertebrae composing the Sa and free Cos in 25 Hooded cranes were 17 or 18, 9 or 10, 12–14 and 6–8, respectively. Total number of vertebrae was 46, 47, 48 or 49, and the vertebral formula was divided into four types including 14 sub-types. Our findings clearly showed various numerical vertebral patterns in both crane species; however, these variations in the vertebral formula may be unrelated to the genetic diversity.

제주재래흑돼지와 Landrace, 교배집단 F2에서 척추의 수적 변이와 도체형질의 상관관계

포유류 중 돼지의 척추 중 요추, 흉추의 수는 고정되지 않은 형질로 개체간의 차이를 나타내는 것으로 알려져 있다. 본 연구는 제주재래흑돼지와 Landrace, 두 품종 간 <TEX>$F_2$</TEX> 교배집단에서 경추 수, 흉추 수, 요추 수, 척추 수 등 체형관련 형질과 도체형질의 상관관계를 살펴보기 위해 수행되었다. 세 축군 모두 경추 수의 변이는 나타나지 않았으나, 흉추 수, 요추 수, 척추 수는 상이한 양상을 보였다. 도체형질의 성적과 요추 수만이 세 축군들 사이에서 통계적인 유의성을 나타내지 않았고(p>0.05), 도체중, 육색, 근내지방도, 등심단면적, 등지방두께, 도체장, 흉추수, 척추 수 등은 통계적인 유의성을 나타내었다(p<0.05). 제주재래흑돼지는 흉추 수 14-16 개, 요추 수 5-6 개, 척추 수 27-29 개의 범위, Landrace는 흉추 수 15-16 개, 요추 수 5-7 개, 전체 척추 수 28-29 개, <TEX>$F_2$</TEX> 교배집단은 흉추 수 14-17, 요추 수 5-7 개, 전체 척추 수 27-30 개로 확인되었다. <TEX>$F_2$</TEX> 교배집단에서 흉추 수와 척추 수의 증가는 도체중, 도체장, 등지방두께의 평균이 유의적으로 다른 양상을 보인다(p<0.05). 또한 척추 수의 증가는 요추 수의 증가보다 흉추 수의 증가에 더 많은 영향을 받는 것으로 나타났다. 흉추 수 및 척추 수의 증가가 등지방두께를 점점 두껍게 만들기는 하지만, 도체중과 도체장 등 경제성을 결정하는 핵심적인 도체형질을 향상시킨다는 점은 추후 제주재래흑돼지나 Landrace 품종을 활용한 양돈산업에서 체형개선을 통한 생산성 증가를 유발할 수 있는 좋은 전략이 될 것으로 판단된다. The number of thoracic and lumbar vertebrae is known to be an unfixed trait among mammals. This study focused on the relationship between numerical variations of cervical (CER), thoracic (THO), and lumbar (LUM) vertebrae and the total number of vertebrae (TNV) and carcass traits in Jejunative black pigs (JBPs), Landrace pigs, and their intercrossed <TEX>$F_2$</TEX> population. There were no numerical variations in CER vertebrae. On the other hand, the numbers of THO and LUM vertebrae and the TNV varied in all three populations. Of the traits investigated in the three populations, only the means<TEX>${\pm}$</TEX>SE of the LUM vertebrae did not show statistical significance (p>0.05). The carcass weights (CW), meat color (MC), marbling score (MS), backfat thickness (BFT), carcass length (CLE), THO vertebrae, and TNV all showed statistical significance (p<0.05). The JBP had 14-16 THO vertebrae, 5-6 LUM vertebrae, and 27-29 TNV. The Landrace pigs had 15-16 THO vertebrae, 5-7 LUM vertebrae, and 28-29 TNV. The <TEX>$F_2$</TEX> population had 14-17 THO vertebrae, 5-7 LUM vertebrae, and 27-30 TNV. In the F2 population, increased numbers of THO vertebrae and TNV were associated with a significant increase in the CW, CLE, and BFT (p<0.05). In particular, the increase in the TNV was caused by an increase in the number of THO rather than LUM vertebrae. Although the animals with a greater number of THO and TNV had thicker backfat, they had a longer CLE and a heavier CW. Both these traits are economically more important than the level of backfat when determining the productivity level. These results suggest that genetic selection to increase the number of vertebrae, especially in Landrace pigs, JBPs, and their related populations, may be an excellent strategy for improving productivity.

Scolecenchelys fuscogularis (Anguilliformes: Ophichthidae, Myrophinae), a new worm eel from Japan

A new species of worm eel (Ophichthidae, subfamily Myrophinae), Scolecenchelys fuscogularis, is described from two specimens collected at 90–147 m depth off the coast of Japan. The new species is characterized by its dorsal-fin origin, which is located posterior to a vertical through the anus, its high total number of vertebrae (146–149), and its uniserial dentition on jaws and vomer. The new species is similar to Scolecenchelys australis and Scolecenchelys tasmaniensis in having 148–152 total and 60–61 preanal vertebrae and its uniserial teeth, but can be distinguished from the latter two species as it has a larger head [8.5–8.8 % of total length (TL) vs. 7.8–8.3 %], a longer trunk (39 % TL vs. 34–35 %), and a shorter tail (52–53 % TL vs. 56–58 %). Although S. fuscogularis most resembles Scolecenchelys chilensis in having 146–159 total and 59–64 preanal vertebrae and uniserial teeth, as well as in the proportions of the head, trunk and tail, the new species differs from the latter in having a smaller head (8.5–8.8 % TL vs. 8.9–9.7 %), a more slender body (body depth 1.5–1.6 % TL vs. 2.3–2.9 %), a more posterior dorsal-fin origin (horizontal distance between the origin and a vertical through the anus 83 % of head length vs. 36–54 %), no groove on the ventral side of its snout, and a dark lower jaw with a patch of melanophores on the ventral side of its branchial basket.

Osteological variation of the olive barb Puntius sarana (Cyprinidae) in Sri Lanka

Abstract : Osteological intra-specific variation was studied in olive barb Puntius sarana Hamilton 1822, from six water bodies in Sri Lanka. Discernible variation was reported in the elements of the cranium, pharyngeal bones and caudal skeleton of the fish. The curvature of the median suture between frontals of the skull roof in fish from the rivers Walawe, Nilwala and the Kirindi Oya was directed opposite to that in fish from the rivers Menik, Gin and Kalu. Shape of the tip of dorsal limb of the pharyngeal bones was either most commonly pointed or truncated. Consistent distinctiveness in the rudimentary neural arch of the compound centrum was observed in the Walawe River population, while double neural spines were present on preural centra (PU2 or PU3) of the caudal skeleton in some populations. The size of the parhypural foramen and epural distance in the caudal skeleton, and the total number of vertebrae of the axial skeleton also showed variation. The results are the first information on osteological variation of P. sarana in Sri Lanka. Keywords : Geographic variation, olive barb, osteological comparison, Puntius sarana taxonomy. Doi: 10.4038/jnsfsr.v39i2.3172 J.Natn.Sci.Foundation Sri Lanka 2011 39 (2):121-128

Occurrence of skeletal deformities and osteological development in red porgy Pagrus pagrus larvae cultured under different rearing techniques

The present study describes the osteological development and the occurrence of skeletal deformities in red porgy Pagrus pagrus larvae in relation to the intensification of the rearing system. Eggs obtained from natural spawning were cultured under two different rearing systems: intensive (100 eggs l⁻¹) in 2000 l and semi-intensive (mesocosm) system (5 eggs l⁻¹) in 40,000 l conico-cylindrical tanks. Fish samples were periodically collected along the development from hatching to juveniles at 95 days post hatching (dph). Osteological development, meristic counts and the presence of skeletal deformities were evaluated. Despite the external appearance of the juveniles being similar to wild standards, X-ray studies revealed a high number of fish (semi-intensive: 37·8%; intensive: 45·5%) with skeletal deformities. Regardless of the rearing system, no significant interaction was found between the per cent of the most common deformities, axial deviations (lordosis and presence of fused vertebrae). Cranial deformities and kyphosis incidences, however, were significantly higher in intensively cultured P. pagrus. Also, the fused vertebrae in these fish were located mainly in the caudal area instead of pre-haemal area for semi-intensively reared P. pagrus. Moreover, a significant interaction was found between the total number of vertebrae and the type of rearing system used; fish from the intensive system showing a higher number of fish with an extra vertebrae (10 abdominal + 15 caudal). Present results suggest a relationship among feeding sequence, osteological development and deformity incidence and location in P. pagrus larvae.

Pseudolaguvia virgulata, a new sisorid catfish (Teleostei: Sisoridae) from Mizoram, northeastern India

Pseudolaguvia virgulata, a new South Asian sisorid catfish species, is described from the Barak River drainage in Mizoram, India. The new species can be distinguished from congeners in having a brown body with two or three narrow, pale longitudinal stripes and a pale Y-shaped marking on the dorsal surface of the head. Additional distinguishing characters from its congeners are a serrated anterior edge of the dorsal spine, the thoracic adhesive apparatus reaching beyond the base of the last pectoral-fin ray, head width, pectoral-fin length, length of dorsal-fin base, dorsal-spine length, body depth at anus, length of adipose-fin base, caudal peduncle length, caudal peduncle depth, snout length, interorbital distance, and total number of vertebrae.

A new species of ladyfish, of the genus Elops (Elopiformes: Elopidae), from the western Atlantic Ocean

v This paper describes Elops smithi, n. sp., and designates a lectotype for E. saurus. These two species can be separated from the five other species of Elops by a combination of vertebrae and gillraker counts. Morphologically, they can be distinguished from each other only by myomere (larvae) or vertebrae (adults) counts. Elops smithi has 73–80 centra (total number of vertebrae), usually with 75–78 centra; E. saurus has 79–87 centra, usually with 81–85 centra. No other morphological character is known to separate E. smithi and E. saurus, but the sequence divergence in mtDNA cytochrome b (d = 0.023–0.029) between E. smithi and E. saurus is similar to or greater than that measured between recognized species of Elops in different ocean basins. Both species occur in the western Atlantic Ocean, principally allopatrically but with areas of sympatry, probably via larval dispersal of E. smithi by oceanographic currents.

A new mastacembelid species from Lake Tanganyika: a case of complex evolutionary history

A detailed morphometric study of 123 specimens identified as Mastacembelus albomaculatus and the six syntypes of M. tanganicae was undertaken. On each specimen, 27 morphometric measurements and 12 meristics were taken. The type series of M. tanganicae contains more than one species, with four specimens attributed to a new species M. reygeli sp. nov. A redescription of M. albomaculatus and a description of the new species are provided. Both species are endemic to the northern and central part of Lake Tanganyika. They can be distinguished based on the number of caudal vertebrae [47-52 (median 49) in M. albomaculatus v. 42-46 (44) in M. reygeli sp. nov.], the total number of vertebrae [85-90 (88) v. 78-83 (81)] and the distance from the snout to the last externally visible dorsal spine (S-LDS) [61.8-67.0 (mean 64.0) v. 66.6-71.5 (68.6)% L(S)]. In addition, intermediate specimens and populations between M. albomaculatus and M. reygeli were discovered from several parts of the lake, but mainly from the southern part. The latter intermediate populations were provisionally identified as introgressed populations.

Study of some meristic features in the Black Sea Caspian Kilka (Clupeonella cultriventris, Clupeidae) introduced in Volga River reservoirs

The results of studies on the morphological variability in kilka (Clupeonella cultriventris) of the Volga River reservoirs are given. In the northward direction in newly established populations, mean values of the number of vertebrae in the truncal part of the backbone (vert. tr.) and total number of vertebrae (vert.) increase. Presumably, the horizontal-stepped cline according to vert. is determined by differences in the thermal regimes in waterbodies during the axial skeleton morphogenesis. Using the principal component analysis by a combination of four features (cs, vert. tr., vert. c., and vert.) three groups of kilka populations were revealed: the upper-middle Volga, the Rybinsk-Sheksna, and the upper Volga. These groups reflect the adaptation process of the invader populations to new environmental conditions.

Morphological and meristic evaluation of the population structure of Anguilla marmorata across its range

The population structure of the giant mottled eel Anguilla marmorata was evaluated using statistical analysis of 21 morphological characters among 13 representative localities across the Indo-Pacific region and as far north as Japan. There were no clear differences in 15 proportional and six vertebral characters using principal component analysis. The total number of vertebrae (N(V)) of A. marmorata at these localities had the widest variation among the morphological and meristic characters examined. A statistical analysis of the N(V) of 1238 specimens from 14 localities that included previously published data found significant differences among Micronesia, French Polynesia and other localities, and between localities in the North Pacific and South Pacific regions. Few differences were detected between specimens from the Indian Ocean and the North Pacific or South Pacific regions. The differences in N(V) among some regions and the population genetic studies of this species indicate that there are at least four populations of A. marmorata (North Pacific, Micronesia, Indian Ocean and South Pacific), which appear to include metapopulation structures in the Indian Ocean and South Pacific. This population structure is consistent with the ocean current patterns in each region and the evolution of migration loops of each spawning population.

Morphological description and intraspecific variability of Mullus surmuletus (Teleostea, Mullidae) vertebral column

Morphological aspects of the vertebral column of Mullus surmuletus from the Sardinian Channel are highlighted. The total number of vertebrae proved to be constant (24) in all examined individuals and the most correct morphological subdivision appears to be into three regions (abdominal, caudal, and intermediate). A difference in the number of abdominal and intermediate vertebrae can be noted: respectively, 7+3 in 39% of individuals and 6+4 in the remaining 61%. The number of caudal vertebrae, however, is always constant (14). These differences were not influenced by size or sex. The present paper shows the first observations of variability, independently of depth or latitude, in the vertebral column of a species with subcarangiform swimming. Since variations in the vertebral composition are determined in the very early stages of ontogenesis, the observed differences might be caused by groups of individuals born in different periods of the same year, in which there could be differences in environmental parameters sufficient to determine variations in the vertebral morphology, but not in the number of vertebrae.

Convergent evolution of the head retraction escape response in elongate fishes and amphibians

Aquatic escape responses have typically been described as C-starts. However, another aquatic escape response, head retraction, occurs in several elongate species, but has never been studied in detail. The goals of this study are to describe the head retraction escape response in a phylogenetically diverse sample of species, to trace the evolution of head retraction in anamniote vertebrates, and to correlate key morphological traits with escape response behavior. In analyzing the evolution of escape behavior, we found that the head retraction escape response has evolved at least six times in anamniote vertebrates. Using independent contrast analysis, the head retraction escape response was found to be correlated with an increase in the total number of vertebrae and an increase in the elongation of an animal. Results from this study indicate a correlation between head retraction as an escape response, elongation of the axial skeleton, and living in structured habitats.

Small and valid species of Trichiurus brevis Wang and You, 1992 and T. russelli Dutt and Thankam, 1966, defined as the “ T. russelli complex” (Perciformes: Trichiuridae)

The taxonomic status of three small [probably less than ca. 600 mm in the largest total length (TL)] and poorly known species, Trichiurus brevis Wang and You, 1992 and T. minor Li, 1992, both from South China Sea, and T. russelli Dutt and Thankam, 1966, from Bengal Bay, was reexamined. Trichiurus brevis and T. russelli, being valid species, are redescribed and a neotype is designated for the latter. Trichiurus brevis is considered to be a senior synonym of T. minor, there being no significant differences in their type specimens. Both valid species, i.e., T. brevis and T. russelli, are similar to T. lepturus Linnaeus, 1758 (larger than ca. 1000 mm TL) in general appearance, but clearly differ from the latter in having the top of the supraoccipital crest situated directly above the posterior margin of eye (vs. well behind posterior margin), lower number of total vertebrae (147–155 and 149–153, respectively, in the former two species vs. 168–173 in T. lepturus), longer dorsal fin base (mean 87% and mean 84% vs. mean 76% of TL), and shorter caudal peduncle length (6% and 8% vs. 13% of TL). Furthermore, the former two species are characterized by having the anal fin origin situated below about the 32nd–35th dorsal fin ray base, whereas in T. lepturus it is situated below the 37th–41st dorsal fin ray base. We recognize that T. brevis and T. russelli together comprise a species group, defined as the “T. russelli complex,” in the genus Trichiurus, the two species differing in snout shape (strongly pointed in T. brevis vs. moderately pointed in T. russelli), snout length [mean 35% vs. mean 30% of head length (HL)], preopercle length (22% vs. 19% HL), predorsal length (70% vs. 63% HL), and dermal eye opening (16% vs. 18% HL).

The effects of substrate and vertebral number on locomotion in the garter snake Thamnophis elegans

1. Locomotor performance of limbless vertebrates depends on the substrate through which individuals move and may result in selection on vertebral number in different habitats. To evaluate the effect of push‐point density on snake locomotion, the density of vegetation and other potential push‐points was quantified at two sites in California (coastal and inland), where conspecific snakes differed greatly in vertebral number (230 and 256 average total vertebrae, respectively; Arnold 1988). The coastal site had significantly higher push‐point densities than the inland site. 2. Five experimental push‐point densities that fell within the natural range of push‐point densities were employed in laboratory trials of juvenile snake locomotion. Density of push‐points significantly affected both crawling speed and head‐to‐tail distance (HTD), an indirect measure of lateral bending. The fastest speed was achieved at an intermediate push‐point density. The shortest HTD occurred when snakes moved through the lowest push‐point density. 3. Sex, total number of vertebrae and total length significantly affected HTD, regardless of push‐point density. Snakes with relatively more vertebrae had a shorter HTD, suggesting they were able to achieve greater lateral bending than snakes with fewer vertebrae. Coastal and inland populations did not differ in HTD during locomotion. 4. Numbers of body and tail vertebrae significantly influenced speed at different push‐point densities. In general, snakes with more body vertebrae were slower than those with fewer, while snakes with more tail vertebrae were faster than those with fewer. Snakes of greater total length were faster at all densities. Coastal snakes crawled faster than inland snakes at all push‐point densities.

Esqueleto pré-sacral e sacral dos lagartos teiêdeos (Squamata, Teiidae)

The morphology of the axial skeleton -pressacral and sacral regions - of the nine genera of Teiidae Boulenger, 1885 comprising Ameiva Meyer, 1795, Callopistes Gravenhorst, 1838, Cnemidophorus Wagler, 1830, Crocodilurus Spix, 1825, Dicrodon Dumeril & Bibron, 1839, Dracaena Daudin, 1802, Kenlropyx Spix, 1825, Teius Merrem, 1820 and Tupinambis Daudin, 1803 is here analysed under a comparative approach. The study is in a generic levei, and the principal conclusions reter to differences on the total number of vertebrae and some aspects of the ribs, especially their insertion and presence.

Interreltionships Among the Species of the Genus &lt;em&gt;Puntius&lt;/em&gt; (Teleostei: Cyprinidae) as Indicated by the Osteology

The osteology of twelve species of Puntius based on a study of 3·43 specimensfrom each species is discribed. Study material ranging in size from 30 mmto 90 mm in standard length included cleared and stained specimens andpreserved specimens in formaline. The skull of the Genus Puntius is characterized by the presence of prcethmoids,lateralethmoids, orbitosphenoids, interorbital septum completelyseparating the two orbits, pharyngeal process which is a elongation of basioccipitals,exoccipitals dividing the foramen magnum in to three parts, triserialpharyngeal teeth on fifth ceratobranchials, and absence of basisphenoid.The total number of vertebrae of Puntius varies from 27 to 41. The firstfour vertebrae are reduced and fused to form the Webarian apparatus whichis a characteristic feature of all Cypriniformes. All the vertebrae exceptthe first four are typified by the presence of Y-shaped epineurals andepihaemals. The caudal skeleton is of primitive pcrciform type with fiveor six hypurals, one parhypural, two uroneurals, two epurals, and fifteenor more branched rays. The main species specific characteristics of the Genus Puntius are thenumbers of vertebrae, gill rakers, pectoral fin rays, and shapes of some skullbones.

Body and Vertebral Proportions in Gymnophiona (Amphibia): Diversity of Morphological Types

The general morphology of gymnophionans, i.e., their body proportions, total number of vertebrae, and variation in vertebral length along the vertebral column, are compared. The biometrical data derive from the monograph of Taylor (1968), supplemented by data from X-rays of specimens from several museum collections. The structural features allow definition of morphological types ranging from extremely stout to thread-like. Consideration of the locomotor role played by the trunk in limbless vertebrates suggests that these types may correspond to morpho-functional ones. However, lack of information about ecological conditions and actual locomotor behavior of most of the Gymnophiona still prevents a test of this hypothesis. The diversity here revealed suggests that Gymnophionan evolution reflects adaptation to a wide range of biotopes, from humid dense soils, the litter and felted rootlets of the rain forest floor, to the aquatic medium.

Revision of the Dalatiid Shark Genus Squaliolus: Anatomy, Systematics, Ecology

Detailed descriptions of the teeth, vertebral column, claspers and viscera are presented for Squaliolus laticaudus and compared with those of two related species, Euprotomicrus bispinatus and Isistius brasiliensis. Jaw teeth of S. laticaudus are heteromorphic and closely resemble those of E. bispinatus. The total number of vertebrae (I = 60) found in S. laticaudus is the lowest of any known shark. The vertebrae most closely resemble those of E. bispinatus in number and structure. The claspers are of squaloid type and display characters which not only may be used to distinguish Squaliolus, but also may indicate a close phylogenetic relationship between S. laticaudus and E. bispinatus. In most visceral characters, S. laticaudus is more similar to E. bispinatus than to I. brasiliensis. Squaliolus is known from the Indo-west Pacific, North Pacific, North and South Atlantic and Indian oceans and seems to prefer waters associated with continental land masses. The vertical distribution is from 500 m during the day to 200 m at night. Squid may comprise a major portion of the diet along with midwater fishes. Bioluminescence is reported for the first time in Squaliolus; the photophores most closely resemble those of E. bispinatus in size and structure.