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Larval Morphology (larval + morphology)
Selected AbstractsParallel evolution of larval morphology and habitat in the snail-killing fly genus TetanoceraJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2006E. G. CHAPMAN Abstract In this study, we sequenced one nuclear and three mitochondrial DNA loci to construct a robust estimate of phylogeny for all available species of Tetanocera. Character optimizations suggested that aquatic habitat was the ancestral condition for Tetanocera larvae, and that there were at least three parallel transitions to terrestrial habitat, with one reversal. Maximum likelihood analyses of character state transformations showed significant correlations between habitat transitions and changes in four larval morphological characteristics (cuticular pigmentation and three characters associated with the posterior spiracular disc). We provide evidence that phylogenetic niche conservatism has been responsible for the maintenance of aquatic-associated larval morphological character states, and that concerted convergence and/or gene linkage was responsible for parallel morphological changes that were derived in conjunction with habitat transitions. These habitat,morphology associations were consistent with the action of natural selection in facilitating the morphological changes that occurred during parallel aquatic to terrestrial habitat transitions in Tetanocera. [source] Morphology of the prometamorphic larva of the spadefoot toad, Scaphiopus intermontanus (Anura: Pelobatidae), with an emphasis on the lateral line system and mouthpartsJOURNAL OF MORPHOLOGY, Issue 2 2002John A. Hall Abstract We provide a detailed description of the larval morphology of the Great Basin spadefoot toad (Scaphiopus intermontanus), a species with documented morphological variability in larval structures associated with feeding. We based our findings on laboratory-raised individuals fed a herbivorous diet. We characterized the morphology of the prometamorphic larva (limited to developmental stages 37 and 38) and then related our findings to the larval ecology of the species. Based on its morphology, such as slightly depressed body, dorsally positioned eyes, anteroventrally oriented oral disc, intermediate tail fin height and slightly attenuated tail tip, relative lack of ventral neuromasts (compared to Xenopus laevis), and pigmentation banding patterns, and habits, such as selection of breeding sites by adults and larval foraging behavior, S. intermontanus can be characterized best as belonging to a (lentic-) benthic guild of anuran larvae. Nevertheless, the larvae are capable of occupying a broader array of ecological niches. Because we characterized individuals raised on a herbivorous diet, our morphological descriptions apply only to the herbivorous S. intermontanus larva (and perhaps to those larvae that are dietary generalists and may feed carnivorously only infrequently). Our findings can serve as a baseline for future morphological and developmental comparisons with the carnivorous morphological variant of this species. J. Morphol. 252:114,130, 2002. © 2002 Wiley-Liss, Inc. [source] Comparison of Development and Larval Growth of Four Venerid ClamsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2005Young-Baek Hur The development and larval morphology of four venerid calms, Ruditapes philippinarum, Mactra veneriformis, Cyclina sinensis, and Meretrix lusoria, which cohabit the intertidal zone in western coastal Korea, were compared using laboratory culture techniques. At 87 ,m, the fertilized eggs of C. sinensis and M. lusoria were the largest and at 53 ,m, those of M. veneriformis were the smallest. D-shaped larvae of M. lusoriu were the largest and those of M. veneriformis were the smallest measuring at 135 ,m and 89 ,m, respectively. D-shaped larvae of R. philippinarum and M. lusoria had symmetrical shoulder angles and an elliptical ventral form, in contrast to the asymmetrical shoulder angles and round ventral forms of M. veneriformis and C. sinensis. In general, pediveliger larvae of all species in the study were yellow, but those of M. veneriforks and C sinenis were a more pronounced yellow. In between the early D-shaped and pediveliger stage, 7 and 17 d elapsed for M. lusonia and C. sinensis larvae, respectively. In the early larval stages for all species, the sheU length was longer than the height. However, shell length and height later became approximately the same size in all species except R. philippinarum, which exhibited a flat shape. These results indicate that for these four venerid clams, the different characteristics in larval growth and external morphology provide the evidence necessary for larval identification of natural seed production despite the fact that they spawn concurrently in the intertidal zone. [source] Phylogeny of Thalassinidea (Crustacea, Decapoda) inferred from three rDNA sequences: implications for morphological evolution and superfamily classificationJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2008L. M. Tsang Abstract The infraorder Thalassinidea is a group of cryptic marine burrowing decapods of which the higher taxonomy is often contentious. The present analysis attempts to reconstruct phylogenetic relationship among 12 of the 13 currently recognized families using partial nuclear 18S, 28S rDNA and mitochondrial 16S rDNA sequences. The infraorder is divided into two distinct clades, with the first clade consisting of Thalassinidae, Laomediidae, Axianassidae and Upogebiidae, and the second clade including Axiidae, Calocarididae, Eiconaxiidae, Callianassidae, Ctenochelidae, Micheleidae, Strahlaxiidae and Callianideidae. Within the first clade, the Upogebiidae is the basal family. The Axianassidae shows low affinity to other laomediid genera indicating that it is a valid family. The interfamilial relationships are less well resolved in the second clade. The Axiidae is paraphyletic with respect to Calocarididae and Eiconaxiidae. Thus, the status of these two latter families is not supported if the currently defined Axiidae is maintained. All three families appear to be basal in the thalassinidean clade. The Micheleidae is closely related to the Callianideidae and they form a sister group to the Strahlaxiidae. The monophyletic Callianassidae aligns with the Micheleidae + Callianideidae + Strahlaxiidae clade. The relationship among the Axiidae + Calocarididae + Eiconaxiidae clade, Callianassidae + Micheleidae + Callianideidae + Strahlaxiidae clade and the Ctenochelidae cannot be resolved which might be due to a rapid radiation of the three lineages. Our results do not support the generally used classification scheme of Thalassinidea and suggest that the infraorder might be divided into two superfamilies instead of three as suggested based on larval morphology, second pereiopod morphology in adults and gastric mill structure. The two superfamilies are Thalassinoidea (i.e. Thalassinidae, Laomediidae, Upogebiidae and Axianassidae) and Callianassoidea (i.e. Axioidea + Callianassoidea, as defined in Martin and Davis (2001) but excluding Laomediidae and Upogebiidae). It also appears that gill-cleaning adaptations are important in thalassinidean evolution while the presence of linea thalassinica is a result of parallel evolution. Résumé L'infraordre des Thalassinidea est un groupe de décapodes marins fouisseurs cryptiques dont la taxonomie au niveau supérieur est souvent controversée. Cette analyse tente de reconstruire les relations phylogénétiques entre 12 familles sur les 13 actuellement reconnues en utilisant les séquences partielles de rDNA nucléaire 18S, 28S et de rDNA mitochondrial 16S. L'infraordre est divisé en deux clades distincts, le premier comprenant les Thalassinidae, Laomediidae, Axianassidae et Upogebiidae, et le deuxième comprenant les Axiidae, Calocarididae, Eiconaxiidae, Callianassidae, Ctenochelidae, Micheleidae, Strahlaxiidae et Callianideidae. Dans le premier clade, les Upogebiidae est la famille basale. Les Axianassidae montre peu d'affinité avec les autres genres de laomedidés, ce qui indique que la famille est valide. Les relations interfamiliales sont moins bien résolues dans le second clade. La famille des Axiidae est paraphylétique par rapport aux Calocarididae et Eiconaxiidae. Ainsi le statut de ces deux dernières familles n'est pas supporté si la famille des Axiidae est maintenue dans sa définition actuelle. Toutes les trois familles apparaissent basales dans le clade thalassinidéen. La famille des Micheleidae est très proche des Callianideidae et elles forment un groupe frère des Strahlaxiidae. La famille monophylétique des Callianassidae s'aligne avec le clade Micheleidae + Callianideidae + Strahlaxiidae. La relation entre le clade Axiidae + Calocarididae + Eiconaxiidae, le clade des Callianassidae + Micheleidae + Callianideidae + Strahlaxiidae et la famille des Ctenochelidae ne peut être résolue, ce qui pourrait être dûà une radiation rapide des trois lignées Nos résultats ne supportent pas le schéma de classification généralement utilisé pour les Thalassinidea et suggèrent que l'infraordre pourrait être divisé en deux superfamilles au lieu de trois comme suggéré sur la base de la morphologie larvaire, de la morphologie du deuxième péréiopode de l'adulte et de la structure du moulin gastrique. Les deux superfamilles sont: les Thalassinoidea (c'est-à-dire Thalassinidae, Laomediidae, Upogebiidae et Axianassidae) et Callianassoidea (c'est-à-dire Axioidea + Callianassoidea, comme définis dans Martin et Davis 2001 mais excluant les Laomediidae et les Upogebiidae). Il apparaît aussi que les adaptations pour le nettoyage des branchies sont importantes dans l'évolution thalassinidéenne alors que la présence de la linea thalassinica est le résultat d'une évolution parallèle. [source] First-instar larval morphology in the subtribe Lydina (Coleoptera, Meloidae, Lyttini), with discussion on its systematic valueMITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 2 2006Federica Turco Abstract First-instar larvae of five species of Lydina, belonging to three genera , Lydus trimaculatus italicus Kaszab, L. europaeus Escherich, Oenas crassicornis (Illiger), O. tarsensis (Abeille de Perrin), and Alosimus chalybaeus (Tauscher) , are described, and new observations on two species previously described Oenas afer (Linnaeus) and Alosimus cirtanus (Lucas) are carried out. The larval morphology of Lydina, studied through light and scanning electron microscope and compared to that of other Lyttini genera, does not support the taxonomic value of the Lydina subtribe since no synapomorphies for this lineage are recognised. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A comparison of the expression of immunity-related rag 1 and ikaros genes with histogenesis of the thymus in Epinephelus malabaricus (Bloch & Schneider)AQUACULTURE RESEARCH, Issue 3 2008John Han-You Lin Abstract Expression of the immunity-related ikaros and rag1 genes during development signals the onset of lymphopoiesis in vertebrates. Partial sequences of ikaros and rag1 in Epinephelus malabaricus were cloned by degenerate primer-mediated reverse transcriptase polymerase chain reaction (RT-PCR). Their expression profiles in the thymus, head kidney, trunk kidney, spleen, intestine, brain, liver and pancreas, and the onset of expression at various developmental stages, were examined by RT-PCR using identical primers. Expressions of both ikaros and rag1 genes were detected as early as 3 days post fertilization (dpf). The thymus is thought to be the first organ of lymphopoiesis to develop in fish; its histogenesis in E. malabaricus was examined and used for comparison. To avoid the potential influence of environmental factors on different hatches, both age and larval morphology were used as indicators of maturation to define the stage of development. A bud-like thymus was observed at 9 dpf; lymphopoietic cells appeared at 19 dpf; and further development, such as cortex/medulla differentiation and the appearance of lymphocytes, occurred by 26 dpf. Trabecula development was detected at 41 dpf. Based on the histological evidence, the lymphoid cell expressed rag1 before the thymus developed, suggesting that extra-thymic lymphopoiesis takes place in E. malabaricus, and that a functional immune system might develop early in the metamorphosis stage. [source] The first known larva of the Australian genus Mystropomus Chaudoir (Coleoptera: Carabidae: Paussinae)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 2 2009Andrea Di Giulio Abstract The monogeneric subtribe Mystropomina Chaudoir (Carabidae: Paussinae: Ozaenini) contains two species endemic to Australia: Mystropomus subcostatus Chaudoir and Mystropomus regularis Bänninger. In this paper, we describe and illustrate the larva of M. subcostatus providing the first larval description in this subtribe, thereby filling an important gap in our knowledge of paussine larval morphology. We compare the structural features of this larva with the other known larvae in the subfamily and provide an identification key to larvae of Australian paussine genera. We find no external structural features that indicate that this larva lives with ants, as do many other members of the carabid beetle subfamily Paussinae. [source] | |||||||||||||