Mosquitofish life history in a Mediterranean wetland

Little is known regarding the life history of Gambusia holbrooki in Europe, particularly in Italy, where it has been introduced in several wetlands since 1922. In order to increase the knowledge of its biology, we tried to clarify its life history in a Mediterranean wetland, comparing our results with those of other authors. The principal aim of this study was to describe the demographic potentialities of the studied population by modal progression analysis. Besides the curvature parameter (0.52 and 0.51 for females and males, respectively) and the asymptotic length values (39.01 and 30.45 for females and males, respectively), we observed a population divided into four age classes, for both sexes, and a longevity of 5 years, with only a limited number of mosquitofish reaching this age (due to a high mortality rate). In addition, reproduction observations were carried out for females. The most interesting aspect concerned the correlation between fecundity and body size, and the capacity of small females to absorb fertilized eggs.     

Metazoan parasite fauna of the round goby Neogobius melanostomus Pallas, 1811 (Perciformes: Gobiidae) collected from the Black Sea coast at Sinop,Turkey

Round gobies (Neogobius melanostomus) were collected from a small stream connected to the Black Sea coast of Sinop, Turkey and examined for metazoan parasites. A total of 122 gobies was investigated throughout a 1‐year period. Long‐term investigations can be useful for finding rare parasites and for determining the diversity and seasonality of parasites. Parasite species recovered were a Digenea gen. sp., Pygidiopsis genata, Ascocotyle sp., Gyrodactylus proterorhini, Dichelyne minutus, Hysterothylacium aduncum, Spiroxys sp., Neoechinohynchus rutilii, and Ergasilus sieboldi. Overall infection prevalence (%) and mean intensity values were 97.5% and 78.2±23.1 parasites per infected fish, respectively. Infection prevalence and mean intensity values for each parasite species in relation to season, fish size, and sex were also determined and discussed.     

Description of Thalamita crosnieri,a new species from Somalia with notes on T. cooperi Borradaile from Somalia and T. demani Nobili from Aldabra (Decapoda,Brachyura)

Summary

A new species, Thalamita crosnieri, is described from Somalia. It belongs to the T. woodmasoni group and is distinguished by the shape of the front and of the gonopod. T. woodmasoni Alcock is restricted to Andamans, southern India and Ceylon while T. crosnieri is known from the eastern coast of Africa and Madagascar. T. cooperi Borradaile (from Somalia) and T. demani Nobili (from Aldabra), belonging to the same group of species, have also been illustrated.     

Rehabilitation of Bryconaethiops yseuxi Boulenger, 1899 (Characiformes: Alestidae) from the Congo River basin,Africa

Bryconaethiops yseuxi Boulenger, 1899 Boulenger, G. A. 1899. Matériaux pour la faune du Congo. Poissons nouveaux du Congo.. Annales du Musée du Congo, Tervuren, Zoologie 1(4: Polypères, Clupes, Mormyres, Characins), : 59–96.  [Google Scholar], originally described from “Haut Congo”, is rehabilitated. The species was synonymized, successively with B. microstoma (Günther, 1873 Günther, A. 1873. New fishes from Angola.. Annals and Magazine of Natural History, London (Series 4), 12(68): 142–144. [Taylor & Francis Online] , [Google Scholar]) and B. macrops Boulenger, 1920 Boulenger, G. A. 1920. Poissons recueillis au Congo belge par l'expédition du Dr. C. Christy.. Annales du Musée du Congo (Série 1), 2(4): 1–38.  [Google Scholar], subsequently rehabilitated, and then again considered as a junior synonym of B. microstoma. Bryconaethiops yseuxi is here considered as a valid species, easily distinguished from all other Bryconaethiops species by its small size (maximum: 72.2 mm SL), 7.5 rows of scales between the dorsal‐fin origin and the lateral line; 11–13/1/8–12 gill rakers on the first gill arch and long dorsal‐fin and anal‐fin bases, respectively, 15.7–17.6% of SL and 22.7–25.9% of SL.