Larval stages of the lake chub, Couesius plumbeus

1981 ◽  
Vol 59 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Lee A. Fuiman ◽  
Joan P. Baker
Keyword(s):  
External Morphology ◽  
Caudal Peduncle ◽  
Larval Stages ◽  
Rhinichthys Cataractae ◽  
Couesius Plumbeus

Three collections of Couesius plumbeus eggs were laboratory reared. Larvae were described with emphasis on external morphology. They were characterized by (1) 25 to 30 preanal myomeres, (2) a diagonal row of melanophores across the surface of the breast, and (3) a concentration of melanophores on the distal hypaxial portion of the caudal peduncle. Larval characteristics were compared with those of its breeding associate Rhinichthys cataractae and other sympatic cyprinids which have similarly high preanal myomere counts.

Pattern of Response of Intact Drosophila to Known Teratogens

1985 ◽  
Vol 4 (4) ◽  
pp. 291-303 ◽  
Author(s):  
R.L. Schuler ◽  
M.A. Radike ◽  
B.D. Hardin ◽  
R.W. Niemeier
Keyword(s):  
Animal Studies ◽  
Test Organism ◽  
Test System ◽  
External Morphology ◽  
Stages Of Development ◽  
Chi Square ◽  
Larval Stages ◽  
Chi Square Test ◽  
Teratogenic Potential ◽  
And Control

Drosophila, as the test organism, was used to assess 17 chemicals. The teratogenic potential of 15 of these chemicals is well established from animal studies or human epidemiology. The test involves examination of adult flies following treatment during larval stages of development. Flies are examined for abnormal external morphology. The incidence of abnormalities in treated and control populations is compared using the Chi-square test. All 17 chemicals were active to varying degrees in the test system. Most chemicals produced a unique response yielding individual patterns of abnormalities. These results suggest that Drosophila may have the potential to become a valuable teratogen screen, but further, more rigorous examination–particularly with nonteratogens–is required.

scholarly journals Redescription of Corydoras guapore Knaack, 1961 (Siluriformes: Callichthyidae), a midwater Corydoradinae species from the rio Guaporé basin

2015 ◽  
Vol 13 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Luiz Fernando Caserta Tencatt ◽  
Carla Simone Pavanelli
Keyword(s):  
Posterior Margin ◽  
Conservation Status ◽  
Original Description ◽  
External Morphology ◽  
Caudal Peduncle ◽  
Descriptive Information ◽  
Current Location ◽  
Pectoral Spine ◽  
Lateral Portion

Corydoras guapore was described from the rio Guaporé, Rondônia State, Brazil, based only in three specimens, two of them merely examined alive in an aquarium and apparently not preserved posteriorly. The current location of these two paratypes is uncertain. In the original description, no standard diagnosis was presented and the descriptive information available is scarce and based only in external morphology. Thus, the aim of this study is to provide a redescription of C. guapore based in several topotypes. Corydoras guapore can be distinguished from its congeners by the presence of a short mesethmoid, with the anterior tip poorly developed; posterior margin of pectoral spine with conical serrations directed towards the origin of the spine; and by the lateral portion of caudal peduncle almost entirely blackened. Information about C. guapore ecology and conservation status are also provided.

LARVAL AND ADULT STAGES OF BRITISH COLUMBIA ANOMURA

1937 ◽  
Vol 15d (10) ◽  
pp. 179-220 ◽  
Author(s):  
Josephine F. L. Hart
Keyword(s):  
British Columbia ◽  
Adult Stage ◽  
External Morphology ◽  
Hermit Crabs ◽  
Larval Stages ◽  
Close Affinity ◽  
Upogebia Pugettensis ◽  
Mode Of Life ◽  
Similar Mode ◽  
Superficial Similarity

The external morphology of the adult stage of four species of Anomura (hermit crabs), Upogebia pugettensis (Dana), Paguristes turgidus (Stimpson), Pagurus beringanus (Benedict) and Orthopagurus schmitti (Stevens) is compared and the larval stages described. Emphasis is placed on the value of larval stages in clarifying our understanding of the taxonomy and interrelationships of the group. This study seems especially important in the Anomura because of the modifications of the adults which fit them for so specialized a mode of existence. It seems probable that some of the similarities exhibited by them are due more to convergence, as a result of similar mode of life, than to close affinity. This is illustrated by the superficial similarity of the adults of Paguristes turgidus and Pagurus beringanus and the dissimilarity of their larvae, as contrasted with apparent differences between the adult Pagurus beringanus and Orthopagurus schmitti, whose larvae are alike. By a comparison of the least modified appendages (the mouth parts) of the adults, the same relationship becomes apparent as was suggested by a study of the larvae. It is therefore concluded that by a comparison of both the larval and adult phases a clearer understanding of the affinities of the species under consideration is obtained.

Multivariate analysis of hybridizing Cyprinidae from the Kananaskis Reservoirs, Alberta

1980 ◽  
Vol 58 (9) ◽  
pp. 1664-1673 ◽  
Author(s):  
G. A. Butcher
Keyword(s):  
Multivariate Analysis ◽  
Principal Components ◽  
Parental Species ◽  
Morphological Characters ◽  
Rhinichthys Cataractae ◽  
Canonical Variates ◽  
Couesius Plumbeus ◽  
Hybrid Group

Principal components and canonical variates analyses of hybridizing Couesius plumbeus (lake chub) and Rhinichthys cataractae (longnose dace) from Upper and Lower Kananaskis Reservoirs, Alberta, using 21 morphological characters, revealed two parental groups bridged continuously by an intermediate hybrid group. This morphological overlap between the hybrids and the parental species indicates that it is not always possible to positively identify "pure" parental individuals from the Kananaskis. Neither backcross nor hybrid F2 individuals could be identified from the analyses, although the Kananaskis R. cataractae showed effects suggestive of either selection or introgression, relative to known R. cataractae from widespread Alberta localities. Rhinichthys cataractae has also declined in numbers relative to C. plumbeus since last studied in 1961. Couesius plumbeus does not show similar effects suggestive of selection or introgression.

External Morphology, Oral Structure and Feeding Behaviour of Kaloula pulchra TADPOLES Gray, 1831 (Amphibia: Anura: Microhylidae)

2017 ◽  
Vol 5 (2) ◽  
pp. 97-103
Author(s):  
H.T. Lalremsanga ◽  
◽  
Saipari Sailo ◽  
R.N.K. Hooroo ◽  
◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Developmental Stages ◽  
Developmental Rate ◽  
External Morphology ◽  
Scanning Electron Micrographs ◽  
Plant Materials ◽  
Larval Stages ◽  
The Family ◽  
The Common ◽  
Scanning Electron

The external morphology and oral structure of various developmental stages in relation to feeding behaviour of Kaloula pulchra Gray, 1831 (Amphibia: Microhylidae) were studied with the help of light microscopyand scanning electron microscopy (SEM). Light and scanning electron micrographs revealed that the oral apparatus at different larval stages are devoid of jaw sheath, labial teeth and keratodonts, instead they have a terminally-oriented, as opposed to an antero-ventrally oriented mouth (umbelliform) known as semicircular labial flap. These features illustrate that the tadpoles within the family Microhylidae could be attributed to assistance in clarifying a certain taxonomic treatment in this family. Observation on the present results showed that tadpoles of Kaloula pulchra are nektonic suspension feeders and started feeding from stage 25 onwards. During the early stages of feeding, they feed mostly on detritus and plant materials and during the later stages of feeding they consumed both phytoplankton and zooplankton. At stage 42, the tadpole stopped feeding and the mouth part is degenerated and gradually transformed in to adult mouth. The preference of Bacillariophyceae and Cyanophyceae in the food habits of this explosive breeding species may be due to the common available food items in their microhabitat that enhanced the faster developmental rate within a short duration.

scholarly journals External Morphology of Larvae of Belgica antarctica Jacobs, 1900 (Diptera, Chironomidae) Obtained from Two Locations in Maritime Antarctica

Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 792
Author(s):  
Paraskeva Michailova ◽  
Julia Ilkova ◽  
Pavlo A. Kovalenko ◽  
Volodymyr A. Gorobchyshyn ◽  
Iryna A. Kozeretska ◽  
...  
Keyword(s):  
Instar Larva ◽  
External Morphology ◽  
Western Antarctic Peninsula ◽  
Fourth Instar Larva ◽  
Maritime Antarctica ◽  
Larval Stages ◽  
Belgica Antarctica ◽  
The Antarctic ◽  
First Time ◽  
Level Identification

The external morphology of the fourth-instar larva of the Antarctic endemic chironomid midge Belgica antarctica is described. Larvae were collected from Jougla Point (Wiencke Island) and an un-named island close to Enterprise Island, off the coast of the western Antarctic Peninsula. Light microscopy was used to examine and document photographically the structures of the mouthparts (mandible, mentum, premandible, labrum), antennae, pecten epipharyngis, clypeus, frontal apotome and posterior parapods. Measurements of the mouthparts are presented. The data obtained are compared with that available in the literature. A number of differences were identified relating to the size of the larvae, the number of teeth on the mandibles, the number of antennal segments and the length of the antennal blade. Malformations of the mandible and mentum are reported for the first time in this species. Features of larvae of taxonomic value that can be used to determine the species in larval stages are presented. These are of utility in using the larvae to reveal relationships with other species. Larvae are also important in ecological and genotoxicological studies, which require accurate species level identification.

A scanning electron microscopic study of the veliger larvae of the scallop argopecten purpuratus

1988 ◽  
Vol 46 ◽  
pp. 284-285
Author(s):  
G.C. Bellolio ◽  
K.S. Lohrmann ◽  
E.M. Dupré
Keyword(s):  
Morphological Description ◽  
Electron Microscopic ◽  
Larval Stages ◽  
Scanning Electron Microscopic Study ◽  
The Pacific ◽  
Argopecten Purpuratus ◽  
Veliger Larvae ◽  
20 Nm ◽  
Ethanol Series ◽  
Scanning Electron

Argopecten purpuratus is a scallop distributed in the Pacific coast of Chile and Peru. Although this species is mass cultured in both countries there is no morphological description available of the development of this bivalve except for few characterizations of some larval stages described for culture purposes. In this work veliger larvae (app. 140 pm length) were examined by the scanning electron microscope (SEM) in order to study some aspects of the organogenesis of this species.Veliger larvae were obtained from hatchery cultures, relaxed with a solution of MgCl2 and killed by slow addition of 21 glutaraldehyde (GA) in seawater (SW). They were fixed in 2% GA in calcium free artificial SW (pH 8.3), rinsed 3 times in calcium free SW, and dehydrated in a graded ethanol series. The larvae were critical point dried and mounted on double scotch tape (DST). To permit internal view, some valves were removed by slightly pressing and lifting the tip of a cactus spine wrapped with DST, The samples were coated with 20 nm gold and examined with a JEOL JSM T-300 operated at 15 KV.

An annotated checklist of mesoplodont whale species (Cetacea, Ziphiidae) discovered during the nineteenth century

2015 ◽  
Vol 42 (2) ◽  
pp. 226-235 ◽  
Author(s):  
G. N. H. Waller
Keyword(s):  
Nineteenth Century ◽  
Additional Data ◽  
Original Description ◽  
Type Specimen ◽  
External Morphology ◽  
Type Locality ◽  
Type Material ◽  
Beaked Whale ◽  
Registration Number ◽  
Annotated Checklist

Eight species of mesoplodont whales (genus Mesoplodon Gervais, 1850) named during the nineteenth century are based on valid descriptions. A checklist with the original description and type material for each of these species is provided. Additional data given may include type locality and illustrative sources, type material holding institution and type registration number(s). The only type specimen for which a record of external morphology was published relates to the 1803 stranding of Sowerby's beaked whale (Mesoplodon bidens).

Larval and juvenile development of the Iceland cockle Ciliatocardium ciliatum (Fabricius, 1780) (Bivalvia: Cardiidae)

2020 ◽  
Vol 324 (2) ◽  
pp. 242-251
Author(s):  
L.P. Flyachinskaya ◽  
P.A. Lezin
Keyword(s):  
Lateral Position ◽  
Larval Shell ◽  
Subtidal Zone ◽  
Larval Stages ◽  
Posterior Shoulder ◽  
Blade Shape ◽  
The Right ◽  
Lateral Structures ◽  
Juvenile Development ◽  
Concentric Structure

The paper considers the development of Ciliatocardium ciliatum from the stage of straight hinge to juvenile. In the White Sea the spawning of C. ciliatum begins at the end of June, larvae at different stages of development occur in plankton until the end of September. The earliest of the larvae found had shell lengths of 123–130 µm. The paper first examined the anatomy and structure of the larval shell of C. ciliatum. During the development, the main stages of organogenesis were described and special attention was paid to the formation of the digestive and muscular systems. The digestive system begins to function when the larva reaches a size of 170–180 µm. The digestive gland has a two-blade shape and is shifted to the right side. The foot is formed at a size of 230 µm, the gill rudiments appear when the larva reaches 270 µm. The development of the larval shell and larval hinge of the mollusc is considered in detail. The development of the larval shell of C. ciliatum is similar to the development of other family members. Throughout all the larval stages, the shell has a rounded shape with a low umbos, and the prodissoconch II has a clearly visible concentric structure. The C. ciliatum larval hinge is characterized by weak differentiation and the absence of pronounced cardinal teeth typical for other Cardiidae. However, the lateral structures of the castle – ridges and flanges – are well developed. The ligament begins to form at a size of 240–250 µm and occupies a lateral position. The settlement of the cockle takes place in September in the subtidal zone. After the metamorphosis, a large radial sculpture is formed on the dissoconch and a number of small spikes are formed at the rib of the posterior shoulder.

External morphology and internal anatomical characters of juveniles of the freshwater drum Aplodinotus grunniens

2018 ◽  
Vol 25 (6) ◽  
pp. 1161
Author(s):  
Haibo WEN ◽  
Xueyan MA ◽  
Pao XU ◽  
Bingqing ZHENG ◽  
Xinhua YUAN ◽  
...  
Keyword(s):  
External Morphology ◽  
Aplodinotus Grunniens ◽  
Anatomical Characters ◽  
Freshwater Drum
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