Asynchronous reproduction in three species of crocodilians in south-eastern Amazonia

We studied reproduction of three species of crocodilians, Paleosuchus trigonatus, Caiman crocodilus and Melanosuchus niger, in the Xingu River, near the Belo Monte hydroelectric dam. The periods of laying and hatching of eggs were estimated for each nest before (2013–2014) and after (2016–2017) the river was dammed and the reservoir was formed. Nesting of the three species occurred between August and December, but was largely asynchronous; nest construction peaked in September for P. trigonatus, October for M. niger and November for C. crocodilus. Reservoir filling had little effect on the laying period of any of the species. Nests of P. trigonatus and M. niger were always within 0–12 m of the bank, whereas nests of C. crocodilus, which nests later in the season when flooding is more likely, were up to 100 m from the nearest water body. There was no relationship between distance from water and the number of eggs in nests, suggesting that larger and presumably more experienced females do not lay at different distances from the bank in any of the species.     

The carcinofauna found in stomach contents of the flying gurnard (Dactylopterus volitans) on the continental shelf of the Campos Basin,Brazil

A total of 3109 crustaceans belonging to 50 taxa distributed in 42 families were found in 117 analysed stomachs of flying gurnard (Dactylopterus volitans). Samples were obtained in April 2008 by the R/V Gyre using a bottom trawl towed in 12 stations at 14–100 m depth on the continental shelf of the Campos Basin, Brazil. The carcinofauna was analysed and the order Calanoida (Copepoda) found to be the most important item in terms of relative abundance and frequency of occurrence, followed by the order Amphipoda (Peracarida), the infraorder Brachyura (Decapoda), the order Stomatopoda and the subclass Myodocopa (Ostracoda). In the order Calanoida, the species Pontellopsis cf. villosa (Pontellidae) represented 98.04% of total crustacean abundance. The diet of Dactylopterus volitans varied according to fish size, with higher diversity of Crustacea at smaller size classes, decreasing in larger fishes. A similar pattern regarding depth was obtained, with greater diversity of taxa in gurnard stomachs caught at shallower depths. Flying gurnard is considered a generalized carnivore of invertebrates, eating mobile macrobenthic organisms, such as crustaceans, and its diet varies with its life stage, without any specific group as its main food source.     

Parasite community of the golden cownose ray Rhinoptera steindachneri Evermann and Jenkins 1891 (Chondrichthyes: Myliobatidae), in Acapulco Bay,Guerrero, Mexico

The parasite community of the ray Rhinoptera steindachneri from Acapulco Bay was examined and quantified; analyses were based on the sex of the host and the date of sampling. A total of 171 specimens of R. steindachneri were examined during July–August of 2010, and May and July of 2012. Twenty-one species of parasites were found: three species of Monogenea; eight adult and one larval species of Cestoda; one larval species of Nematoda; five species of Copepoda; two species of Isopoda; and one species of Hirudinea. Cestodes had the greatest species richness (43% of the total species), followed by the copepods (24%). Two species of cestode, Glyphobothrium sp. and Rhinebothrium sp., were collected only from adult rays. At the component community level, species richness showed statistically significant variation between 13 and 16 species, which is similar to previous reports for other species of rays. The parasite component communities and infracommunities of R. steindachneri exhibited similar patterns: high species number and low numerical dominance by a particular species of parasite. The differences of body size of male vs. female rays, and a change in diet and feeding behaviour with the age of R. steindachneri, are likely important factors in the structuring of their parasite communities.     

Promoting Entrepreneurship through a Community Learning Model – Case Study: Green Businesses

This article presents a community learning model formulated by Engineers Without Borders Colombia with the aim of providing communities with tools to create sustainable productive solutions which have relevancy for members and for potential customers. The goal of this formulation is to promote learning processes that are guided by decisions made by community members to propose sustainable and replicable initiatives. The model applicability is evidenced through a case study devoted to strengthening community-led green businesses in the Guavio Province, Colombia by collecting lessons and conclusions. Ultimately, this collection will prove useful in replicating the learning model in other similar rural communities.

     

A Proposal for the Automatic Computation of Envelopes of Families of Plane Curves

Journal of Systems Science and Complexity - The idea of envelope of a family of plane curves is an elementary notion in differential geometry. As such, its implementation in dynamic geometry...     

Redescription of Retilaskeya horrida (di Monterosato, 1874) comb. nov. and a re-evaluation of the taxonomic affinity of the genus Retilaskeya (Caenogastropoda: Triphoroidea)

The family Cerithiopsidae H. Adams and A. Adams, 1853 is distributed worldwide, and comprises around 800 extant species divided into ~40 genera. The most speciose genus within the family is Cerithiopsis Forbes and Hanley, 1850, a taxon currently used as a general receptacle rather than as a proper phylogenetic lineage. We hereby redescribe the rare species Cerithiopsis horrida di Monterosato, 1874, review its nomenclature, known material, and distribution as well as figure the entire protoconch, operculum, and radula for the first time. Our results highlight extreme differences between ‘Cerithiopsis’ horrida and the Cerithiopsis type species Cerithiopsis tubercularis (Montagu, 1803) and strong morphological and radular similarities with species belonging to the genus Retilaskeya Marshall, 1978. A wide discussion lists several taxa that might be ascribed to the same group of species, which presumably constitute a different worldwide lineage. Pending relevant molecular phylogenetic studies of the Triphoroidea Gray, 1847, for morphological conformity we suggest transferring ‘Cerithiopsis’ horrida to the genus Retilaskeya, and the same action is presumably appropriate for its possible sister species ‘Cerithiopsis’ leopardus Rolán and Gori, 2013. Finally, Retilaskeya better conforms to Newtoniellidae Korobkov, 1955 than Cerithiopsidae.