Extended Analysis of Hybridization in Sunfishes (Centrarchidae) Using an Adjusted Hybrid Index Method

1973 ◽  
Vol 30 (12) ◽  
pp. 1901-1904 ◽  
Author(s):  
Miles H. A. Keenleyside ◽  
R. K. Misra ◽  
David W. Bateson

Sunfish collected from Pinehurst Lake, Ontario, were sorted into three groups: bluegill (Lepomis macrochirus), pumpkinseed (L. gibbosus), and a group possessing some of the color patterns of each of the other two. Eleven morphological characters of each fish were analyzed by a hybrid index method, and by an adjusted index which allowed: a) calculation of sampling variances of individual and mean index estimates and, b) testing of hypotheses about the position of suspected hybrids relative to the parental populations. This method, applied to single characters and to combinations of characters, showed that the anomalous group resembled bluegills in four characters, pumpkinseeds in one, and were exactly intermediate in the others. The simplest explanation of these results is that the intermediate group was a population of bluegill × pumpkinseed hybrids.This use of the hybrid index permits increased precision over earlier methods in comparing suspected hybrid individuals with their putative parent populations.


1972 ◽  
Vol 29 (8) ◽  
pp. 1173-1180 ◽  
Author(s):  
Don E. McAllister ◽  
Pierre Jolicoeur ◽  
Hiroshi Tsuyuki

Ten morphological characters and two electrophoretic characters were studied in nearly 200 specimens of johnny and tessellated darters from the Ottawa area. The data were analyzed using a simple character index and principal component analysis. The frequency distribution of the character index was trimodal, and specimens could be resolved into three groups: those typical of johnny and tessellated darters, and a group of intermediates. The two extreme groups were interpreted as representing two valid species, Etheostoma nigrum Rafinesque and Etheostoma olmstedi Storer, and part of the intermediate group was inferred to consist of interspecific hybrids. Hybrids were estimated to constitute less than 7.6%. There was no clear evidence of backcrossing. Most specimens could be clearly identified with one or the other of the two species. A key is provided.



2021 ◽  
Vol 61 ◽  
pp. e20216156
Author(s):  
Flávio A. Bockmann ◽  
Roberto E. Reis

Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade.



1997 ◽  
Vol 35 (11-12) ◽  
pp. 107-112 ◽  
Author(s):  
A. M. Shaban ◽  
G. E. El-Taweel ◽  
G. H. Ali

In the present study, the effect of UV radiation on the inactivation of a range of microorganisms was studied. Each organism was seeded into sterile tap water and exposed to UV in batch experiments with changing turbidities. In addition, the effect of UV on microbial communities in river Nile water was examined. It was found that 1min contact time (0.5L/min flow rate) was effective against vegetative cells levels almost reaching zero (except with Staphylococcus aureus). On the other hand, spore-forming bacteria, Candida albicans and coliphage were more resistant to UV. This contact time caused coenobia cells in single form with Scenedesmus obliquus while for Microcystis aeruginosa colonies broke into smaller groups. Exposure of Nile water microbial communities to UV showed that yeasts and Aeromonas survived better than the other organisms while in the phytoplankton partial fragmentation occurred in some algal groups. The protective effect of turbidity differed between organisms, with increased contact time under conditions of stable turbidity having no effect on the organisms. At 20 NTU the UV radiation had no effect on the morphological characters of algal cells. In reactivation experiments, it is clear that photoreactivation, and not dark repair, takes place with bacterial cells. Only coliphage had no photoreactivation and dark repair responses although with coliphage and host, both reactivation processes worked well. Moreover, the irradiated algae regained their normal shape after 3 days in suitable media and enough light.



2021 ◽  
Vol 1771 (1) ◽  
pp. 012004
Author(s):  
Ling Chao Gao ◽  
Li Ming Yao ◽  
ZhiWei Yang ◽  
Fei Zheng


2005 ◽  
Vol 26 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Francisca do Val ◽  
Paulo Nuin

AbstractThe systematics and phylogenetic relationships of the family Leptodactylidae are controversial as is the intrafamilial phylogeny of the leptodactylids. Here we analyze the relationships of the leptodactylid subfamily Hylodinae. This subfamily has been considered to be monophyletic and composed of three genera, Hylodes, Crossodactylus and Megaelosia. In the present study 49 characters were used, based on different studies on Leptodactylidae phylogeny. Maximum parsimony methods with unweighted and successively weighted characters were used to estimate the phylogeny of the Hylodinae. Upon analysis, the data provided further evidence of the monophyletic status of the three genera, with Megaelosia being the basal genus and the other two genera being sister taxa. The analysis with successive weighting results in a more resolved topology of the species subgroups of the genus Hylodes and separates this genus from Crossodactylus and confirms that the hylodines are monophyletic.



1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.



Zootaxa ◽  
2021 ◽  
Vol 4958 (1) ◽  
pp. 489-502
Author(s):  
FILIPE MICHELS BIANCHI

The Carpocorini are distributed worldwide, and it is one of the most speciose tribes within the Pentatomidae with 127 genera and more than 500 valid species. Recently, Adustonotus Bianchi was described to contain eight species formerly placed within Euschistus Dallas. Among them, Adustonotus grandis (Rolston) and Adustonotus latus (Dallas) are remarkable for their large size. Herein, the phylogenetic position of a new taxon is inferred by a total evidence analysis based on 85 morphological characters and four molecular markers. Adustonotus graziae sp. nov. is described, and is recovered in a polytomic lineage, including A. grandis and A. latus. These species share a solid combination of features that enable them to be separated from the other Adustonotus species (e.g., large size, the humeral angles spatulate and exceptionally produced, and the capsula seminalis shortened). Illustrations of external and internal genitalia, and a distributional map are provided. 



2010 ◽  
Vol 3 (1) ◽  
pp. 63-96 ◽  
Author(s):  
Rodrigo Pereira ◽  
Satoko Narita ◽  
Daisuke Kageyama ◽  
Finn Kjellberg

AbstractArthropods are sexually dimorphic. An arthropod individual usually differentiates into a male or a female. With very low frequencies, however, individuals with both male and female morphological characters have repeatedly been found in natural and laboratory populations of arthropods. Gynandromorphs (i.e., sexual mosaics) are genetically chimeric individuals consisting of male and female tissues. On the other hand, intersexes are genetically uniform (i.e., complete male, complete female or intermediate in every tissue) but all or some parts of their tissues have either a sexual phenotype opposite to their genetic sex or an intermediate sexual phenotype. Possible developmental processes (e.g., double fertilization of a binucleate egg, loss of a sex chromosome or upregulation/downregulation of sex-determining genes) and causal factors (e.g., mutations, genetic incompatibilities, temperatures or endosymbionts) for the generation of gynandromorphs and intersexes are reviewed and discussed.



Author(s):  
Dirk Erpenbeck ◽  
Sue List-Armitage ◽  
Belinda Alvarez ◽  
Bernard M. Degnan ◽  
Gert Wörheide ◽  
...  

We present a 28S rDNA gene tree of selected Raspailiidae, Axinellidae and other demosponges to obtain insight into raspailiid phylogeny and character evolution. The Raspailiidae in our data set cluster in a well-supported clade, distinguished from Axinellidae, Agelasida and Hadromerida. Raspailia (s.s.), Eurypon, Sollasella, Aulospongus and Ectyoplasia form a Raspailiidae clade. Some Raspailia subgenera, in particular R. (Parasyringella), are not retrieved monophyletically. Trikentrion falls into the Thrinacophorinae, and not the Cyamoninae as earlier hypothesized. The axinellid genera Ptilocaulis and Reniochalina also cluster with Raspailiidae, distant from the other Axinellidae. The suitability of particular morphological characters for raspailiid phylogeny is discussed.



2021 ◽  
Vol 5 (2) ◽  
pp. 177-187
Author(s):  
Lourdes Y. Echevarría ◽  
Pablo J. Venegas ◽  
Luis A. García-Ayachi ◽  
Pedro M. Sales Nunes

We describe a new species of Selvasaura from the montane forests of the eastern slopes of the Andes in northern Peru, based on external and hemipenial morphological characters and previous phylogenetic analyses. The new species can be differentiated from the other two Selvasaura species in having keeled dorsal scales usually flanked by longitudinal striations, in adults and juveniles; adult males with a yellow vertebral stripe bordered by broad dark brown stripes on each side and a unilobed hemipenis surrounded by the branches of the sulcus spermaticus. The description of the new species contributes information about new states of diagnostic characters of Selvasaura and natural history.



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