This study describes the morphology and arrangement of the cuticular structures of Hyalella castroi González, Bond-Buckup & Araujo, 2006 and Hyalella pleoacuta González, Bond-Buckup & Araujo, 2006, to identify specific characters that can be used in taxonomstudies of this genus. The entire cuticular surface of both species was examined by optical and scanning electron microscopy. The data obtained were compared with available information for other members of Peracarida, mainly Amphipoda and Isopoda. Five different types of cuticular structures, including 30 types of setae, four types of microtrichs, three types of pores, and some structures formed by setules and denticles were identified. The results were compared with other groups of gammarids, and peracarideans, such as Thermosbaenacea and Isopoda. The use of cuticular structures as a tool for taxonomic studies showed important results, not only at species level, but also at genus, and family levels

The freshwater amphipod genus Hyalella in Brazil has the second highest diversity in South America; it is only surpassed by the diversity found in th

We present an assemblage of terrestrial isopods in Parque Estadual de Itapuã, southern Brazil, and estimate the contribution of two species to the leaf litter processing. After one year of sampling, we obtained 3748 individuals of six species and four eco-morphologic groups (in order of abundance): Balloniscus glaber Araujo & Zardo, 1995, Atlantoscia floridana (van Name, 1940), Pseudodiploexochus tabularis (Giambiagi de Calabrese, 1939), Trichorhina sp., Alboscia itapuensis Araujo & Quadros, 2005 and Novamundoniscus gracilis Lopes & Araujo, 2003. Total monthly density corresponded to 368 individuals per square meter. The species A. itapuensis and N. gracilis represented less than 1% of total individuals. All the others showed aggregated distribution. Atlantoscia floridana and B. glaber had the highest proportion of individuals occurring together (88%) and a significant species association. Their monthly biomass averaged 4.92 kg ha-1 for B. glaber and 0.97 kg ha-1 for A. floridana. Consumption rates, obtained in the lab (in mg mg-1 day-1) were 0.34 ± 0.04 and 0.70 ± 0.18 for B. glaber and A. floridana, respectively and assimilation efficiency was about 30%. We estimated that both species together could process 860 kg leaves ha-1 year-1.

Many arthropods, including terrestrial isopods, are capable of entering a state of tonic immobility upon a mechanical disturbance. Here we compare the responses