scholarly journals Unusual Morphotypes of the Giant Barrel Sponge off the Coast of Barbados

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 663
Author(s):  
Joseph R. Pawlik ◽  
Denise C. Manker ◽  
James S. Evans ◽  
Patrick M. Erwin ◽  
Susanna López-Legentil
Keyword(s):  
Environmental Factors ◽  
Genetic Differentiation ◽  
Morphological Variation ◽  
Species Complex ◽  
Cylindrical Shape ◽  
Mtdna Coi ◽  
Tropical Reefs ◽  
Cryptic Species Complex ◽  
The Caribbean ◽  
Barrel Sponge

Giant barrel sponges (GBSs) belong to a cryptic species complex (Xestospongia spp.) and are found on tropical reefs worldwide. Over their range, including most of the Caribbean, GBSs have a cylindrical shape, with variation in height, diameter and surface complexity. However, off the southwest coast of Barbados, GBSs mostly exhibit a clam shape or a tub shape, interspersed with a few that have the normal barrel morphotype, suggesting that this variation is not due to environmental factors. Haplotype identification (mtDNA-COI) of six clam and six normal sponges indicated no clear genetic differentiation based on morphotype; hence, this morphological variation remains unexplained.

scholarly journals Phylogeographic Investigations of the Widespread, Arid-Adapted AntlionBrachynemurus sackeniHagen (Neuroptera: Myrmeleontidae)

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Joseph S. Wilson ◽  
Kevin A. Williams ◽  
Clayton F. Gunnell ◽  
James P. Pitts
Keyword(s):  
Genetic Differentiation ◽  
Species Complex ◽  
Evolutionary History ◽  
Mitochondrial Gene ◽  
Distinct Species ◽  
Mountain Building ◽  
Phylogeographic Pattern ◽  
Late Neogene ◽  
Cryptic Species Complex ◽  
Divergence Dates

Several recent studies investigating patterns of diversification in widespread desert-adapted vertebrates have associated major periods of genetic differentiation to late Neogene mountain-building events; yet few projects have addressed these patterns in widespread invertebrates. We examine phylogeographic patterns in the widespread antlion speciesBrachynemurus sackeniHagen (Neuroptera: Myrmeleontidae) using a region of the mitochondrial gene cytochrome oxidase I (COI). We then use a molecular clock to estimate divergence dates for the major lineages. Our analyses resulted in a phylogeny that shows two distinct lineages, both of which are likely distinct species. This reveals the first cryptic species-complex in Myrmeleontidae. The genetic split between lineages dates to about 3.8–4.7 million years ago and may be associated with Neogene mountain building. The phylogeographic pattern does not match patterns found in other taxa. Future analyses within this species-complex may uncover a unique evolutionary history in this group.

Complex spatial patterns of genetic differentiation in the Caribbean mustard hill coral Porites astreoides

Coral Reefs ◽  
2021 ◽  
Author(s):  
Florentine Riquet ◽  
Aurélien Japaud ◽  
Flávia L. D. Nunes ◽  
Xaymara M. Serrano ◽  
Andrew C. Baker ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Spatial Patterns ◽  
Porites Astreoides ◽  
The Caribbean

The Use of Protein Electrophoresis for Determining Species Boundaries in Amphipods

Crustaceana ◽  
1993 ◽  
Vol 65 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Barbara A. Stewart
Keyword(s):  
Gene Flow ◽  
Genetic Differentiation ◽  
Morphological Variation ◽  
Protein Electrophoresis ◽  
Species Boundaries ◽  
Allopatric Populations ◽  
A Value ◽  
Electrophoretic Data

AbstractThe use of protein electrophoretic data for determining species boundaries in amphipods is addressed. Analysis of published literature on genetic differentiation in amphipods showed that pairs of allopatric populations which have genetic identities (I) above a value of 0.85 probably represent intraspecific populations, whereas pairs of populations which have genetic identities below about 0.45 probably represent different species. It was recommended that if I values fall between 0.45 and 0.85, additional factors such as evidence of a lack of gene flow between the populations, and concordant morphological variation should be considered.

Description of Three Pristionchus Species (Nematoda: Diplogastridae) from Japan that Form a Cryptic Species Complex with the Model Organism P. pacificus

2012 ◽  
Vol 29 (6) ◽  
pp. 403 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Erik J. Ragsdale ◽  
Matthias Herrmann ◽  
Werner E. Mayer ◽  
Ralf J. Sommer
Keyword(s):  
Cryptic Species ◽  
Species Complex ◽  
Model Organism ◽  
Cryptic Species Complex

Influence of fishers’ behaviour on the catchability of surface tuna schools in the Venezuelan purse-seiner fishery in the Caribbean Sea

1999 ◽  
Vol 56 (3) ◽  
pp. 394-406
Author(s):  
Daniel Gaertner ◽  
Mauricio Pagavino ◽  
Jesus Marcano
Keyword(s):  
Environmental Factors ◽  
Daily Activity ◽  
Caribbean Sea ◽  
Catch Rate ◽  
Causal Network ◽  
Fine Scale ◽  
Network Approach ◽  
Logistic Regressions ◽  
The Caribbean ◽  
The Impact

The influence of Venezuelan skippers' behaviour on the catchability of surface tuna schools was modelled using logistic regressions. Data obtained from observers onboard purse seiners indicated that fishers' fine-scale decisions, such as chasing and setting a school, were influenced by (i) the skipper's skill, (ii) the fishing equipment used (e.g., whether a bird radar was used or not), (iii) the features of the tuna school, and (iv) some environmental factors. The connections among the decisions related to the fishing process and these variables were synthesized in a causal network approach. Results clearly showed that schools (i) composed by fishes under 2 kg and (ii) where biomass was lower than 5 metric tons were disregarded by fishers. Because fishers used these thresholds to decide when to set the net, modifications in their behaviour over the years may introduce serious biases in the analysis of any catch rate and abundance relationship. An average daily activity record of a purse seiner shows the proportion of time spent in searching and in setting activities and highlights the impact that the use of new fishing equipment may have on fishing power.

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